CAT OPERATION PREVENTIVE MAINTENANCE & SERVICE GUIDE DBT RB2-88 ROOF BOLTER (A6474X196) - PDF

OPERATION, PREVENTIVE MAINTENANCE AND SERVICE GUIDE MODEL RB2-88 ROOF BOLTER

NOTICE THIS GUIDE CONTAINS IMPORTANT OPERATION AND SAFETY INFORMATION AND SHOULD BE KEPT AVAILABLE TO THOSE PERSONNEL INSTALLING AND OPERATING THIS EQUIPMENT.

A6474X196

NOTICE THIS GUIDE IS NOT INTENDED TO BE A COMPLETE OPERATING OR SERVICE MANUAL OR GUIDE. IT IS PREPARED ON THE BASIS THAT THE INDIVIDUAL OPERATING THIS UNIT IS TRAINED IN THE OPERATION OF UNITS OF THIS TYPE AND HAS HAD SPECIAL TRAINING TO OPERATE THIS UNIT. FURTHER, IT IS ASSUMED THAT THE INDIVIDUAL WILL TAKE NECESSARY PRECAUTIONS TO ENSURE SAFE OPERATION FOR HIMSELF AND FOR OTHERS. THE TEXT IN NO WAY COVERS ALL POSSIBLE CONTINGENCIES OR OPERATING PROCEDURES. THIS GUIDE IS DESIGNED TO BE OF GENERAL ASSISTANCE. IF PROCEDURES OR CONDITIONS ARE ENCOUNTERED WHICH ARE NOT INCLUDED IN THIS GUIDE, THE OPERATOR SHOULD GET EXPERT ASSISTANCE BEFORE ATTEMPTING TO OPERATE OR REPAIR THE MACHINE. FOR THE DBT AMERICA SERVICE DEPARTMENT, CALL (540)9804530.

DBT AMERICA ASSUMES NO RESPONSIBILITY FOR THE PERFORMANCE OR OPERATION OF THIS UNIT IF IT IS ALTERED IN ANY MANNER.

NOTICE SOME ILLUSTRATIONS IN THIS GUIDE MAY SHOW GUARDS OR COVERS REMOVED FOR PURPOSES OF CLARITY. NEVER OPERATE UNIT WITHOUT ALL GUARDS AND COVERS IN PLACE. SOME ILLUSTRATIONS IN THIS GUIDE MAY SHOW UNITS WITH OPTIONAL EQUIPMENT INSTALLED. THIS OPTIONAL EQUIPMENT MAY BE PURCHASED FROM YOUR LOCAL DBT AMERICA DEALER. SOME ILLUSTRATIONS IN THIS MANUAL MAY BE OF PROTOTYPE MODELS. PRODUCTION MODELS MAY VARY IN SOME DETAIL. CONTINUING IMPROVEMENT AND ADVANCEMENT OF PRODUCT DESIGN MAY CAUSE CHANGES TO YOUR MACHINE WHICH MAY NOT BE INCLUDED IN THIS PUBLICATION. EACH PUBLICATION IS REVIEWED AND REVISED, AS REQUIRED, TO UPDATE AND INCLUDE THE CHANGES IN LATER ADDITIONS. DBT AMERICA RESERVES THE RIGHT TO MODIFY OR MAKE CHANGES WITHIN A SPECIFIC MODEL GROUP WITHOUT NOTICE AND WITHOUT INCURRING ANY LIABILITY TO RETROFIT UNITS PREVIOUSLY SHIPPED FROM THE FACTORY. CONTACT YOUR DBT AMERICA DEALER FOR MAINTENANCE THAT IS NOT COVERED IN THIS PUBLICATION.

OPERATION, PREVENTIVE MAINTENANCE AND SERVICE GUIDE MODEL RB2-88 ROOF BOLTER

A6474X196 REVISION 2 June, 2003 DBT America 4041 Wurno Road Pulaski, VA 24301

THIS GUIDE IS TO BE USED ONLY WITH THE MODEL RB2-88 ROOF BOLTER. OTHER MODELS IN THIS SERIES MAY HAVE OPERATING FEATURES UNLIKE THE MODEL RB2-88.

TABLE OF CONTENTS Page IMPORTANT SAFETY INSTRUCTIONS..................................................................................... 1 MAJOR HAZARDS .................................................................................................................... 2 SAFETY PRECAUTIONS AND GUIDELINES .......................................................................... 4 OVERVIEW ................................................................................................................... 4 PRE-START INSPECTION ........................................................................................... 4 STARTING ..................................................................................................................... 4 OPERATION ................................................................................................................. 4 STOPPING .................................................................................................................... 5 MAINTAINANCE ........................................................................................................... 5 INTRODUCTION ........................................................................................................................ 7 SECTION 1 - GENERAL INFORMATION ................................................................................. 9 CONTROLS AND INDICATORS ............................................................................................. 17 OPERATOR’S COMPARTMENT ...................................................................................... 17 FIRE SUPPRESSION ACTUATORS .......................................................................... 17 STOP/START SWITCH................................................................................................. 18 PANIC BAR (Operator’s Compartment) ...................................................................... 18 TRAM PEDAL .............................................................................................................. 19 VALVE BANK CONTROL LEVERS (Operator’s Compartment) ................................ 19 CABLE REEL CONTROL LEVER ............................................................................... 19 STEERING WHEEL .................................................................................................... 20 GAUGE BLOCK .......................................................................................................... 20 P.T.O. DIVERSION VALVE (Optional) ........................................................................ 21 JET FILL DIVERSION VALVE (Optional) .................................................................... 21 BOOM ARM CONTROLS ............................................................................................ 21 POSITIONING CONTROLS (Left Boom) .................................................................... 22 POSITIONING CONTROLS (Right Boom) ................................................................. 23 CRADLE SWING CONTROL LEVERS ....................................................................... 23 CRADLE LIFT CONTROL LEVERS ............................................................................ 23 SUPPORT ARM CONTROL LEVERS ........................................................................ 23 UP-FRONT STEERING ............................................................................................... 23 DRILLING CONTROLS ............................................................................................... 23 DRILL SUMP CONTROL LEVER ............................................................................... 24 BOOM FEED CONTROL LEVER ............................................................................... 24 FAST FEED CONTROL LEVER ................................................................................. 24 ROTATION CONTROL LEVER .................................................................................. 24 INCH TRAM CONTROL LEVER ................................................................................. 25 PANIC BARS (Booms) ................................................................................................ 25 EMERGENCY STOP BUTTON (Left Boom) ............................................................... 25 STOP/START SWITCH (Right Boom) ......................................................................... 25 CONTROLLER BOX CONTROLS ............................................................................... 26 LIGHT SWITCH LEVER .............................................................................................. 26 CIRCUIT BREAKER LEVER ....................................................................................... 26 “OPTIONAL” DOLLY BAR CONTROL LEVERS ......................................................... 26

TABLE OF CONTENTS (Continued) Page SECTION 2 - OPERATION ...................................................................................................... 27 PRELIMINARY CHECKS .................................................................................................. 27 BEFORE OPERATING MACHINE .................................................................................... 27 TO OPERATE MACHINE .................................................................................................. 28 DRILLING .......................................................................................................................... 31 EXTENSION STEELS SELECTION .................................................................................. 33 DRILLING WITH EXTENSION STEELS ........................................................................... 34 DUAL RELIEF VALVE ...................................................................................................... 36 FUNCTION .................................................................................................................. 36 LIMITING TORQUE ..................................................................................................... 36 LIMITING THRUST ..................................................................................................... 36 MECHANICAL FUNCTIONS ....................................................................................... 36 RESIN BOLTS ............................................................................................................. 37 DRILL OPTIONS AND ADJUSTMENTS .......................................................................... 38 INSTALLATION OF MECHANICALLY ANCHORED ROCK BOLTS .............................. 39 INSTALLATION OF FULLY GROUTED RESIN BOLTS ................................................. 41 SHUTDOWN PROCEDURE .............................................................................................. 43 SAFETY PRECAUTIONS FOR UNDERGROUND OPERATION .................................... 44 GENERAL DRILLING AND BOLTING SAFETY ......................................................... 44 TRAMMING SAFETY RULES ..................................................................................... 44 SHUTTING DOWN THE ROOF BOLTER .................................................................. 45 HAZARD ZONE ........................................................................................................... 46 TOWING A DISABLED MACHINE ................................................................................... 47 SECTION 3 - GENERAL MAINTENANCE INSTRUCTIONS .................................................. 49 BEFORE MAINTENANCE OR SERVICING ............................................................... 49 MAINTENANCE CHECK LIST .......................................................................................... 50 PERIODIC MAINTENANCE PROCEDURES ................................................................... 51 EVERY SHIFT ............................................................................................................. 51 DAILY .......................................................................................................................... 55 WEEKLY ...................................................................................................................... 58 EVERY THREE MONTHS ........................................................................................... 60 EVERY SIX MONTHS ................................................................................................. 62 YEARLY ....................................................................................................................... 63

TABLE OF CONTENTS (Continued) Page LUBRICATION CHART ..................................................................................................... 64 LUBRICANT SPECIFICATIONS ....................................................................................... 66 SECTION 4 - MECHANICAL FUNCTIONS ............................................................................. 69 GENERAL .......................................................................................................................... 69 MECHANICAL OPERATION ............................................................................................ 69 PRIMARY POWER SOURCE ..................................................................................... 69 TRAM AND STEERING SYSTEM .............................................................................. 70 DRILLING ROTATION ................................................................................................ 71 CRADLE, BOOM, AND SUPPORT ARM ASSEMBLIES ............................................ 72 PRIMARY POWER BOOM OPERATION .................................................................... 73 CRADLE ....................................................................................................................... 74 SUPPORT ARM OPERATION ..................................................................................... 75 CRADLE, BOOM, AND SUPPORT ARM ASSY: PINS, BUSHINGS, & SLIDERS ...... 76 TURNTABLE ................................................................................................................ 77 DUST COLLECTION SYSTEM .................................................................................... 78 CABLE REEL ............................................................................................................... 79 MECHANICAL COMPONENTS ........................................................................................ 80 REEL DRIVE ............................................................................................................... 80 PUMP DRIVE ............................................................................................................... 81 TRAM REDUCER ......................................................................................................... 82 MULTIPLE DISC BRAKE ............................................................................................. 83 DRILL BOX ................................................................................................................... 84 DUST SYSTEM VACUUM BLOWER ........................................................................... 85 DUST COLLECTORS .................................................................................................. 87 SECTION 5 - HYDRAULIC FUNCTIONS ................................................................................ 89 PURPOSE .......................................................................................................................... 90 GENERAL .......................................................................................................................... 90 BASIC ELEMENTS OF HYDRAULICS ............................................................................ 96 HYDRAULIC CIRCUITS .................................................................................................. 102 TRAM CIRCUITS ............................................................................................................. 102 REAR TRAM CIRCUIT .............................................................................................. 104 FRONT TRAM CIRCUIT ........................................................................................... 105 INCH TRAM CIRCUIT ............................................................................................... 106 STEERING CIRCUIT ................................................................................................. 107 ROTATION (DRILLING CONTROL) VALVE BANK CIRCUIT .................................. 108 ROTATION CIRCUIT ................................................................................................ 109 FAST FEED CIRCUIT ............................................................................................... 110 FEED (BOOM LIFT) CIRCUIT .................................................................................. 111 CRADLE VALVE BANK CIRCUIT ............................................................................. 112

TABLE OF CONTENTS (Continued) Page SUPPORT ARM CIRCUIT ......................................................................................... 113 CRADLE SWING CIRCUIT ....................................................................................... 114 CRADLE LIFT CIRCUIT ............................................................................................ 115 CABLE REEL CIRCUIT ............................................................................................. 116 HYDRAULIC COMPONENTS ......................................................................................... 117 DOUBLE TANDEM PUMP ........................................................................................ 117 GEAR TYPE HYDRAULIC MOTORS ....................................................................... 118 TRAM MOTORS ........................................................................................................ 119 STEERING VALVE .................................................................................................... 121 CONTROL VALVES .................................................................................................. 122 UNIT CONTROL VALVE OPERATION ..................................................................... 123 MOTION CONTROL VALVE ..................................................................................... 124 DUAL RELIEF VALVE ............................................................................................... 125 PILOT RELIEF VALVE .............................................................................................. 126 CARTRIDGE RELIEF VALVES ................................................................................. 127 PORT RELIEF VALVES ............................................................................................ 128 PILOT OPERATED CHECK VALVES ...................................................................... 130 SHUTTLE VALVES .................................................................................................. 130 FLOW CONTROL VALVE .......................................................................................... 131 FLOW LIMITERS ........................................................................................................ 132 HYDRAULIC JACKS .................................................................................................. 133 HYDRAULIC FLUID FILTER ...................................................................................... 134 PRESSURE GAUGES ............................................................................................... 134 SECTION 6 - ELECTRICAL FUNCTIONS ............................................................................ 135 GENERAL ........................................................................................................................ 136 SEQUENCE OF OPERATION, AC MACHINE ............................................................... 136 AC MOTOR ............................................................................................................... 139 STARTER (CONTROLLER) BOX (AC) ..................................................................... 140 STARTER BOX COMPONENTS, AC MACHINES ......................................................... 141 CIRCUIT BREAKER .................................................................................................. 141 STARTER .................................................................................................................. 141 HEADLIGHT SWITCH ............................................................................................... 141 TRANSFORMER ....................................................................................................... 141 THERMAL OVERLOAD RELAY ............................................................................... 141 CONTROL STATION SWITCH (START/STOP SWITCH) ........................................ 142 EMERGENCY STOP SWITCH ................................................................................. 143 CABLE REEL ............................................................................................................ 144

RB2-88 ROOF BOLTER

DBT AMERICA

IMPORTANT SAFETY INSTRUCTIONS This guide provides important information to familiarize you with safe operating and maintenance procedures for the Model RB2-88 Roof Bolter. Even though you may be familiar with similar equipment, you MUST read and understand this guide before operating this unit.

Safety is everyone's business and must be one of your primary concerns. Knowing the guidelines covered in the following paragraphs will help provide for your safety, for the safety of those around you, and for the machine's proper operation.

LOOK FOR THESE SYMBOLS WHICH POINT OUT ITEMS OF EXTREME IMPORTANCE TO YOU AND YOUR CO-WORKERS’ SAFETY. READ AND UNDERSTAND THOROUGHLY. HEED THE WARNING AND FOLLOW THE INSTRUCTIONS.

WARNING WARNING SAFETY NOTES MUST BE FOLLOWED. YOUR MISTAKE MIGHT RESULT IN SERIOUS INJURY OR DEATH TO YOURSELF OR OTHERS.

CAUTION CAUTION SAFETY NOTES ARE ALSO VERY IMPORTANT. THEY POINT OUT TO YOU WHERE YOUR MISTAKES COULD CAUSE PHYSICAL HARM TO YOU OR OTHERS, OR DAMAGE TO THE MACHINE.

NOTICE NOTICE IS USED TO NOTIFY PEOPLE OF INSTALLATION, OPERATION, OR MAINTENANCE INFORMATION WHICH IS IMPORTANT BUT NOT HAZARDRELATED.

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MAJOR HAZARDS AREA WHERE HAZARD CAN OCCUR

HAZARD WHAT CAN HAPPEN IF PRECAUTIONS AND SAFEGUARDS ARE NOT OBEYED

SAFEGUARDS HOW TO AVOID THE HAZARD

ENTIRE MACHINE

Movement of machine can run over or crush body parts between machine and other objects and cause irreparable injury or death.

Keep alI people out of Hazard Zone (Figure 25). Use extreme caution when moving machine. The machine should be properly shutdown (see page 43) before the operator leaves the operator's compartment.

OPERATOR'S AREA (Cab)

Operation of machine with head, arms, or hands outside of operator's compartment could cause irreparable injury or death if body parts strike or are crushed between machine and outside objects.

Keep head, arms, hands, inside operator's compartment at alI times.

Keep the machine’s protective canopy securely in place at all times.

OPERATOR'S AREA (Positioning Controls)

Movement of machine can run over or crush body parts between machine and other objects and cause irreparable injury or death.

Boom positioning controls are for maneuvering machine between bolt holes only, never pass beyond last row of permanent supports. Machine must be operated from tram station for long distance moves.

DRILL BOOM ASSEMBLY

Drill boom could crush persons, hands, feet, or legs in between drill boom and face or rib of mine.

Turning drill box could catch clothing, belts, tools, etc., pulling persons into the drilling assembly.

Keep alI persons, hands, feet, or Iegs away from drilling assembly during drilling operation. Machine must be properly shutdown (see page 43) before servicing and securely supported before working around or under the drill boom.

OPERATOR’S AREA (Drilling ControIs)

Operation of drilling controls with head, feet, arms, or hands outside of protective canopy area, could cause irreparable injury or death if body parts are struck or crushed by falling debris.

Keep head, feet, arms, hands, under protective canopy at alI times during bolting or drilling operations.

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MAJOR HAZARDS AREA WHERE HAZARD CAN OCCUR

HAZARD WHAT CAN HAPPEN IF PRECAUTIONS AND SAFEGUARDS ARE NOT OBEYED

SAFEGUARDS HOW TO AVOID THE HAZARD

UNDERNEATH DURING SERVICE

Machine raised for service could fall, crushing persons body, hands, feet, or legs underneath.

If machine must be raised for service, it must be securely blocked so that all wheels may safely turn (see Maintenance page 49).

ELECTRICAL (Trailing Cable, Controller, Motors, Etc.)

Electrical shock could cause severe injury or death.

The electrical system should be maintained by certified electricians. The power should be disconnected and locked out at the power center before servicing the trailing cable, motors or controller.

HYDRAULIC

If part of a hydrauIic circuit is removed while there is a load on a cylinder in the circuit, the cylinder could drop the load.

Securely block or remove any load from the cylinder before disconnecting the hose or circuit.

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SAFETY PRECAUTIONS AND GUIDELINES OVERVIEW Before you operate, maintain or in any other way, use this unit READ and STUDY this guide. KNOW how to safely use the unit's controls and what you must do for safe maintenance.

ALWAYS wear or use the proper safety items required for your personal protection.

KNOW and follow the safety procedures of each mine when operating this unit.

If you have ANY QUESTIONS about the safe use or maintenance of this unit: ASK YOUR SUPERVISOR - NEVER GUESS - ALWAYS CHECK

PRE-START INSPECTION Read this entire guide BEFORE attempting to operate this unit. You should be familiar with the controls and their functions before the unit is energized.

INSPECT your machine by doing a pre-operational inspection. Have any malfunctioning, broken or missing parts corrected or replaced before use.

VERIFY that all maintenance has been performed.

VERIFY that all the instruction and safety labels are in place and readable. important as any other equipment on the machine.

These are as

CLEAN any foreign material from the operator's compartment.

THIS Model RB2-88 Roof Bolter was shipped from the factory equipped with protective canopies.

These canopies MUST be securely in place before operating the unit.

STARTING DO NOT operate any levers or pedals (located inside the operator’s compartment) from outside the operator's compartment to keep the machine from hitting you or other personnel.

FOLLOW the instructions in the OPERATION section of this guide (page 27) when the machine is to be used.

DO NOT operate any levers or pedals if anyone is in the Hazard Zone (page 46).

BE familiar with the operation of the Panic Strips and be prepared for the sudden stop when the panic strips are struck.

OPERATING ALWAYS make sure that no person or obstruction is in your line of travel BEFORE starting the unit into motion.

NEVER climb onto, or climb out of the machine while it is in motion.

DO NOT operate the machine with any part of your body outside of the operator's compartment in order to prevent body parts from being crushed between the machine and outside objects.

USE extreme caution and be observant when working in close quarters or in congested or blindtravel areas.

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NEVER carry passengers to prevent the passengers from being thrown off or crushed between the machine and outside objects.

NEVER grasp any object when it is rotating in the drill box.

ALWAYS look in all directions BEFORE changing your direction of travel.

ALWAYS use the automated temporary roof support assembly during drilling and bolting operations.

ALWAYS remain under drill station canopies during drilling and bolting operations.

ALWAYS follow all safety rules of each particular mine when operating the machine.

If problems or equipment malfunctions are encountered while operating the unit, it must be properly shutdown (see page 43) and the problem repaired. Continuing to use malfunctioning equipment can not only be unsafe for the operator and other personnel, but can lead to further damage to the unit as well.

STOPPING DO NOT leave the operator's compartment with the unit running. ALWAYS properly shutdown the unit (page 43) before leaving the operator's compartment.

ALWAYS park the unit on solid, level ground. If this is not possible, park the unit at a right angle to the slope to prevent accidental movement of the machine.

Use proper flags, warnings or barriers when parking in areas of traffic. Chock all four wheels in both directions whenever possible.

MAINTENANCE AVOID, whenever possible, servicing, cleaning or examining the machine in congested areas.

AVOID, whenever possible, servicing or providing maintenance to the unit unless the wheels are adequately chocked to prevent accidental movement of the unit.

DO NOT alter the electrical or hydraulic settings from that indicated in this operation guide or as set at the factory.

ALWAYS replace damaged or lost decals or metal instruction plates. Refer to the Parts Manual for the proper location and part number of decals and plates.

DISCONNECT and lock out power at the power center before performing service or maintenance to prevent electrical shock or accidental start-up or movement of machine.

ALWAYS follow all safety procedures of each particular mine when performing maintenance.

It is important that any procedure not specifically recommended in this guide be thoroughly evaluated from the standpoint of safety before it is implemented.

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INTRODUCTION

MODEL RB2-88 ROOF BOLTER FIGURE 1

The DBT America Model RB2-88 Roof Bolter can be one of the most useful and safe machines found underground today, IF IT IS OPERATED CORRECTLY BY A PROPERLY TRAINED OPERATOR. Before operating the Model RB2-88 Roof Bolter, study the illustration (Figure 8, page 17 and Figure 17, page 22) to become familiar with the controls and read the description of each control.

If a word is in quotation marks and capital letters, such as "OFF" or "ON," that word is found as a label on the machine.

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DBT AMERICA

SECTION 1 - GENERAL INFORMATION PURPOSE OF THIS GUIDE This guide provides operating and maintenance information for operators of the Model RB288 Roof Bolter. Maintenance and lubrication procedures are those normally performed by maintenance personnel. The techniques of roof bolting are beyond the scope of this guide and no such information is included. The guide is divided into six (6) sections:

SECTION 1 - GENERAL This section contains general information about the roof bolter.

SECTION 2 - OPERATION This section explains pre-operation, start-up, and basic operating procedures.

SECTION 3 - MAINTENANCE This section explains the periodic maintenance procedures; it also includes lubrication requirements.

SECTION 4 - MECHANICAL This section explains the major mechanical components and assemblies, and explains their function.

SECTION 5 - HYDRAULIC This section explains the hydraulic circuits and the operation of major hydraulic components.

SECTION 6 - ELECTRICAL This section explains the electrical system and the operation of major electrical components.

OPERATION - FAMILIARIZATION In operation, the roof bolter is trammed to the bolting location from the relative safety of the tramming cab. When the intended location of the first row of bolt holes is reached, the operator and his assistant move to the front (cradle) controls. An "inch tram” control at the front of the machine, used in conjunction with the cradle swing controls, allows for accurate final positioning of the machine. Once the machine is properly positioned, the operators raise the support arms to the mine roof. They then lower the cradle stab feet to the mine floor and begin operating.

The operator then moves from the cradle controls to the drilling controls, which are located under the drill station canopies Leavinq the dual relief valve in the "OFF” position (or turning it “ON” for resin bolting), each operator drills a starter hole, using a pilot bit. Operators then complete the drilling with a longer bit and extensions as necessary. Switching the dual relief to the “ON” position (or turning it “OFF” for resin bolting) each operator installs a bolt and torques it into place.

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NOTICE THROUGHOUT THIS GUIDE THE TERMS RIGHT-HAND AND LEFT-HAND (OR RIGHT AND LEFT) ARE USED TO DESCRIBE THE LOCATION OF COMPONENTS, THEY REFER TO POSITION RELATIVE TO AN OPERATOR SEATED IN THE TRAM CAB AND FACING FORWARD (SEE FIGURE 2 BELOW.)

FIGURE 2

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DBT AMERICA

GENERAL MACHINE LAYOUT FIGURE 3

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GENERAL HAZARD LABEL PLACEMENT FIGURE 4

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HAZARD LABELS FIGURE 5 13

DBT AMERICA

RB2-88 ROOF BOLTER

HAZARD LABELS FIGURE 6

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DBT AMERICA

HAZARD LABELS FIGURE 7

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DBT AMERICA

CONTROLS AND INDICATORS OPERATOR'S COMPARTMENT

WARNING BEFORE OPERATING ANY PEDALS OR LEVERS ON THE ROOF BOLTER, ALWAYS MAKE SURE THAT NO ONE IS IN THE HAZARD ZONE (FIGURE 25, PAGE 46). DO NOT OPERATE ANY LEVERS OR PEDALS (LOCATED INSIDE THE OPERATOR’S COMPARTMENT) FROM OUTSIDE THE OPERATOR'S COMPARTMENT. In the operator's compartment are the controls and indicators used in the normal operation of the machine (Figure 8). These include: the fire suppression actuator, stop/start switch, panic bar, tram pedal, cable reel control lever, cradle lift control levers, steering wheel, gauge block, P.T.O. diversion valve (optional) and jet fill diversion valve (optional).

OPERATOR’S COMPARTMENT FIGURE 8

CAUTION THIS UNIT IS EQUIPED WITH A TRAM STATION CANOPY. BE CAREFUL NOT TO HIT YOUR HEAD WHEN ENTERING OR EXITING THE TRAM STATION. FIRE SUPPRESSION ACTUATORS - The two fire suppression (remote) actuators (Figure 9) are located to the operator's right while sitting in the reverse seat and on the left rear corner of the machine. This particular suppression system is pneumatically actuated and extinguishes with dry chemicals. To actuate the fire suppression system from either of the two actuators, pull the safety pin and strike downward on the plunger. Immediately after the plunger is struck, dry chemical will be dispensed throughout the machine.

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FIRE SUPPRESSION ACTUATORS FIGURE 9 STOP/START SWITCH - The pump stop/start switch (Figures 8 and 10) is located to the operator's left, if seated in the forward tram seat. The stop/start switch is used to start the hydraulic pumps electric motors. To start the electric motors, depress the “START” button.

Release the “START” button once the electric motors start. To “STOP” the electric motors, depress the “STOP” button.

STOP/START SWITCH FIGURE 10

WARNING CHECK TO SEE THAT MOTORS ARE RUNNING IN THE CORRECT DIRECTION. IF EITHER MOTOR IS RUNNING IN WRONG DIRECTION, SHUTDOWN MACHINE AT ONCE (FOR SHUTDOWN PROCEDURE SEE PAGE 43).

WARNING THE PANIC BAR SHOULD ONLY BE ACTUATED IN EMERGENCY SITUATIONS. BE PREPARED FOR A SUDDEN STOP WHEN PANIC BAR IS ACTUATED. PANIC BAR (Operators Compartment) - The panic bar (Figure 8) is located to the operator's left while sitting in the tram forward seat and to the operators right while sitting in the tram reverse seat. The panic bar is used to break the control circuit only in emergency situations, stopping all motors.

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RB2-88 ROOF BOLTER

DBT AMERICA

NOTICE THE ROOF BOLTER'S TRAM SPEED IS VARIABLE. THIS MEANS THAT THE FARTHER THE TRAM PEDAL IS DEPRESSED THE FASTER THE ROOF BOLTER WILL TRAVEL. TRAM PEDAL - The tram pedal (Figure 11) is used to regulate the speed of the roof bolter. It is operated by the left foot when seated in the tram forward seat and by the right foot when seated in the tram reverse seat. To tram forward depress the foot pedal on the forward side of the pedal and to tram in reverse depress the pedal on the reverse side of the pedal.

TRAM PEDAL FIGURE 11

NOTICE ONLY SPRING CENTERED VALVE SECTIONS ARE USED ON THE RB2-88 ROOF BOLTER. THIS MEANS THAT ONCE THE CONTROL LEVER IS RELEASED BY THE OPERATOR THE CONTROL LEVER AUTOMATICALLY RETURNS TO THE CENTERED (NEUTRAL) POSITION. VALVE BANK CONTROL LEVERS (Operator's Compartment) - In the operator's compartment located below and to the left of the forward tram seat is a group of control levers (Figures 8 and 12). These control levers control the cable reel and the elevation of both left and right cradles (optional). The hydraulic system pressure relief valve is set at the factory at 900 PSI, and should not be changed.

CABLE REEL CONTROL LEVER - The cable reel control lever (Figure 12, page 20) is used to control the cable reel when paying out or when picking up cable during tramming operations. To pay out cable while tramming forward move the valve handle toward the front of the machine. To pick up cable while tramming in reverse move the handle toward the rear of the machine.

CAUTION BE CAREFUL OPERATIONS.

NOT

TO

DAMAGE

TRAILING

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CABLE

DURING

TRAMMING

DBT AMERICA

RB2-88 ROOF BOLTER

CABLE REEL VALVE BANK FIGURE 12 STEERING WHEEL - The steering wheel (Figures 8 and 13) is used to steer the machine. To steer right while moving forward (left while moving in reverse), rotate the steering wheel in a clockwise direction. To steer left while moving forward (right while moving in reverse), turn steering wheel in counter clockwise direction.

STEERING WHEEL FIGURE 13 GAUGE BLOCK - The gauge block (Figures 8 and 14) is located to the operator's right while sitting in the tram reverse seat. The gauge block consists of (4) four pressure gauges which provides a means of measuring oil pressure in individual circuits.

GAUGE BLOCK FIGURE 14

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DBT AMERICA

P.T.O. DIVERSION VALVE (Optional) - The P.T.O. diversion valve (Figures 8 and 15) is located to the operator's right while sitting in the tram reverse seat, it provides the roof bolter operator or other qualified individual in the work area with optional capability to power accessory equipment within the work area. To activate the P.T.O. pull the lever towards the operator and to deactivate push the lever back to its original position.

P.T.O. DIVERSION VALVE FIGURE 15 JET FILL DIVERSION VALVE (Optional) - The jet fill diversion valve (Figures 8 and 16) is Iocated to the operator's right while sitting in the tram reverse seat. The jet fill option provides the operator with an automatic controlled hydraulic oil replenishing system. To activate the P.T.O. pull the lever towards the operator and to deactivate push the lever back to its original position.

JET FILL DIVERSION VALVE FIGURE 16 BOOM ARM CONTROLS - On the outside of both right and left booms are the controls and indicators (Figure 17) for drilling operations and maneuvering machine between bolt holes.

These include: the positioning controls, drilling controls, inch tram control, up-front steering controls, panic bar, stop/start switch, emergency stop, and dual relief valve.

CAUTION WHEN OPERATING THE ROOF BOLTER FROM CONTROLS ON BOOM ARM, NEVER PASS BEYOND LAST ROW OF PERMANENT SUPPORTS. OPERATE ROOF BOLTER FROM THE TRAM STATION FOR PLACE-CHANGE OR OTHER LONG DISTANCE MOVES.

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BOOM CONTROLS FIGURE 17 POSITIONING CONTROLS (Left Boom) - The positioning controls (Figures 17 and 18) on the left boom include: the cradle swing, cradle lift, and support arm.

POSITIONING CONTROLS (LEFT BOOM) FIGURE 18

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POSITIONING CONTROLS (Right Boom) - The positioning controls (Figures 17 and 19) on the right boom include: the cradle swing, cradle lift, support arm and up-front steering.

POSITIONING CONTROLS (RIGHT BOOM) FIGURE 19 CRADLE SWING CONTROL LEVERS - The cradle swing control levers (Figures 18 and 19) for both right and left booms operate in the same manner. They control the swing of both booms individually inward and outward. To swing the boom in the outward direction, pull the control lever towards the operator and to swing the boom inward, push the control lever away from the operator.

CRADLE LIFT CONTROL LEVERS - The cradle lift contol levers (Figures 18 and 19) for both right and left booms operate in the same manner. They control the elevation of both cradles individually. To raise the cradle, pull the control lever toward the operator and to lower the cradle, push the control lever away from the operator.

SUPPORT ARM CONTROL LEVERS - The support arm control levers (Figures 18 and 19) for both right and left support arms operate in the same manner. They control the elevation of both support arms individually. To raise the support arm pull the control lever toward the operator and to lower the support arm push the control lever away from the operator.

UP-FRONT STEERING - The up-front steering control lever (Figure 19) is for maneuvering machine between bolt holes during drilling operations only. To steer machine to the right, pull the control lever toward the operator and to steer the machine to the left push the control lever away from the operator.

WARNING DURING DRILLING AND BOLTING OPERATIONS OPERATOR MUST REMAIN UNDER DRILL STATION CANOPY AT ALL TIMES. DRILLING CONTROLS - The drilling controls (Figures 17 and 20) located on the outside and to the front of each boom are used to control the drilling and bolting operations. These levers control the drill sump, boom feed, rotation and fast feed.

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DRILLING CONTROL VALVE BANK FIGURE 20 DRILL SUMP CONTROL LEVER - The drill sump control lever (Figure 20) provides the operator with approximately 12” of drill box adjustment for straight line bolting or to correct misalignment of drill box. To move the drill box forward, push the control lever away from the operator and to move the drill box backward, pull the control lever towards the operator. When the control lever is released it will automatically return to the neutral position.

BOOM FEED CONTROL LEVER - The boom feed control lever (Figure 20) is used for raising and lowering the elevation of the boom at normal operating speed. To raise the boom push the control lever away from the operator and to lower the boom pull the control lever towards the operator. When the desired elevation of the boom is met release the control lever and it will automatically return to the neutral position.

FAST FEED CONTROL LEVER - The fast feed control lever (Figure 20) provides the operator with a means of increasing the speed (beyond the normal speed that is delivered by the boom feed) of the boom elevation. To raise the boom push the control lever away from the operator and to lower the boom pull the control lever towards the operator. When the desired elevation of the boom is met release the control lever and it will automatically return to the neutral position.

ROTATION CONTROL LEVER - The rotation control lever (Figure 20) is used to control the rotation of the drill box. To start the drill box rotating in (CW) clockwise direction, push the control lever away from the operator and to start the drill box rotating in (CCW) counterclockwise direction pull the control lever towards the operator. To stop the rotation of the drill box release the control lever and it will automatically return to its neutral position.

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WARNING THE INCH TRAM CONTROL LEVER IS FOR MANEUVERING ROOF BOLTER BETWEEN BOLT HOLES ONLY. MACHINE MUST BE OPERATED FROM TRAM STATION FOR PLACE-CHANGE OR OTHER LONG DISTANCE MOVES. WHEN OPERATING THE ROOF BOLTER FROM CONTROLS ON BOOM ARM, NEVER PASS BEYOND LAST ROW OF PERMANENT SUPPORTS. INCH TRAM CONTROL LEVER - The inch tram control lever (Figures 17 and 21) is located on the outside and to the rear of the right boom. The inch tram control lever is used for maneuvering the machine between bolt holes during drilling operations only. To tram machine forward pull the tram control lever towards the operator. To tram the machine in reverse push the control lever away from the operator.

INCH TRAM CONTROL LEVER FIGURE 21

WARNING THE PANIC BARS SHOULD ONLY BE ACTUATED IN EMERGENCY SITUATIONS. BE PREPARED FOR A SUDDEN STOP OF ALL ROOF BOLTER OPERATIONS WHEN PANIC BAR IS ACTUATED. PANIC BARS (Booms) - The panic bars (Figure 17) located to the outside of each boom are used to shutdown the machine only in an emergency situation. The panic bars are not intended as an “ON-OFF” switch for normal operation. To actuate panic bar(s) strike in a downward motion with hand.

EMERGENCY STOP BUTTON (Left Boom) - The emergency stop button (Figure 17) located on the outside of the left boom, it is used to shutdown the machine only in emergency situations.

The emergency stop button is not intended as an “ON-OFF” switch for normal operation. To actuate the emergency stop switch strike the panic bar in a downward motion with hand.

STOP/START SWITCH (Right Boom) - The stop/start switch (Figure 17) located on the outside of the right boom is used to start the hydraulic pump's electric motor's. To start the electric motor's, depress the “START” button, release the button once the electric motor's have started.

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To “STOP” the electric motor's, depress the “STOP” button. The stop/start switch is also used in conjunction with the right boom panic bar as an emergency stop switch, to actuate strike in a downward motion on the panic bar.

CONTROLLER BOX CONTROLS - The controller box (Figure 22) located on the left rear of the machine has two control switche levers. These switches control the lighting system and the circuit breaker reset.

CONTROLLER (STARTER) BOX FIGURE 22 LIGHT SWITCH LEVER - The light switch lever (Figure 22) located on the left side of the controller box, activates either pair of the machines headlights. One pair is located on the front end (boom end) and the other pair is located on the rear end of the machine.

CIRCUIT BREAKER LEVER - The circuit breaker lever (Figure 22) located on the front cover of the controller box is used to reset the circuit breaker when it has tripped. If the circuit breaker has tripped, the reset lever must be moved to the “RESET” position first, and then to the “ON” position.

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SECTION 2 - OPERATION WARNING FAILURE TO READ AND UNDERSTAND ALL OPERATING INSTRUCTIONS BEFORE STARTING THE ROOF BOLTER COULD RESULT IN SERIOUS INJURY OR DEATH TO THE OPERATOR OR PERSONS AROUND THE MACHINE OR CAUSE DAMAGE TO THE MACHINE. READ ALL INSTRUCTIONS CAREFULLY BEFORE ATTEMPTING TO START OR OPERATE MACHINE. UNDERSTAND THE FUNCTION(S) OF ALL CONTROLS BEFORE STARTING THE ROOF BOLTER. READ AND FOLLOW THE INSTRUCTIONS ON ALL WARNING TAGS ON THE MACHINE. OBSERVE ALL REGULATIONS AND SAFETY PRECAUTIONS. NEVER OPERATE A ROOF BOLTER WHICH HAS BEEN DAMAGED OR IS NOT OPERATING PROPERLY. ANY PART OF THE ROOF BOLTER WHICH DOES NOT FUNCTION PROPERLY CAN BE A HAZARD. REPORT IT IMMEDATELY TO YOUR SUPERVISOR. MAKE SURE THAT NO ONE IS IN THE HAZARD ZONE (FIGURE 25, PAGE 46) BEFORE STARTING THE ROOF BOLTER.

PRELIMINARY CHECKS Before applying power to the machine, make a visual inspection for components or assemblies which may have been damaged during shipping.

Remove blocks, chains, tools, etc. which may have been left on or around the machine.

Check the fluid and lubricant levels at the following points (see Lubrication Chart, Figure 47): 1. HYDRAULIC OIL LEVEL - Check level in sight gauge.

2. BLOWER - Check oil level.

3. DRILL BOXES - Check oil level.

4. HYDRAULIC FILTERS - Check indicator.

5. TORQUE HUBS - Check oil level.

BEFORE OPERATING MACHINE 1. Inspect machine completely and repair all defects before proceeding.

2. Clear machine operating area of personnel.

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TO OPERATE MACHINE 1. Inspect machine for any damage.

2. Check power rating. This information can be found on plate located on the control box cover and on the serial number plate.

3. Check control valve positions. All valve levers must be in the neutral position before starting machine.

4. Follow trailing cable back to power source, inspect the condition of the trailing cable and make sure cable is correctly identified at breaker, fuse or nips connection. Make sure all connections are secure.

5. Turn machines circuit breaker switch to the "ON” position and turn light switch "ON” to the intended direction of travel.

WARNING NEVER OPERATE ANY LEVERS OR PEDALS (LOCATED INSIDE THE OPERATORS COMPARTMENT) FROM OUTSIDE THE OPERATORS COMPARTMENT. THIS MACHINE IS EQUIPED WITH A CANOPY. BE CAREFUL NOT TO HIT YOUR HEAD WHEN ENTERING OR LEAVING THE OPERATORS COMPARTMENT. THIS MACHINE MUST NOT BE OPERATED WITHOUT THE CANOPY IN PLACE.

6. Get into the operators compartment in proper position, facing intended direction of travel.

7. Depress electrical start button and check to see that electric motors are running in proper direction - this information is marked near each blower clutch control. If the motors are running in wrong direction, shutdown machine at once.

WARNING DO NOT OPERATE MACHINE IF ALL PANIC BARS ARE NOT OPERATIONAL.

8. Strike the panic bars to confirm that they are operational.

NOTE: By striking either panic bar the circuit breaker should trip-out.

9. Observing all safety precautions, carefully test each hydraulic circuit controlled from the valve banks except the tram circuit. Visually check machine for proper operation and loose parts.

Note any unusual noises.

10. Check dust collection system for proper suction. If necessary - empty canisters and replace filters.

11. Before tramming machine from the rear tram area (operator’s compartment), the cradles stab feet must be completely elevated to provide ground clearance.

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WARNING DO NOT OPERATE THE ROOF BOLTER WITH ANY PART OF YOUR BODY OUTSIDE THE OPERATOR'S COMPARTMENT TO PREVENT HAVING BODY PARTS CAUGHT BETWEEN THE MACHINE AND OUTSIDE OBJECTS. BE SURE NO ONE IS IN THE HAZARD ZONE (FIGURE 25, PAGE 46) BEFORE OPERATING ANY LEVERS OR PEDALS.

WARNING THE INCH TRAM AND STEERING CONTROLS LOCATED ON THE RIGHT BOOM ARE FOR MANEUVERING MACHINE BETWEEN BOLT HOLES ONLY. LONG DISTANCE MOVES MUST BE MADE FROM INSIDE THE OPERATOR'S COMPARTMENT. 12. Get into the operator's compartment in proper position (Figure 23), facing the intended direction travel.

OPERATOR POSITION FIGURE 23 13. Move the steering wheel slowly back and forth to get the feel of how the machine will steer.

WARNING THE FARTHER THE FOOT PEDAL IS DEPRESSED, THE FASTER THE ROOF BOLTER WILL TRAVEL.

CAUTION THE TRAILING CABLE MUST BE HANDLED WITH CARE WHILE TRAMMING MACHINE.

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WARNING MAKE SURE NO ONE IS IN THE HAZARD ZONE (FIGURE 25, PAGE 46). BEFORE TRAMMING MACHINE. 14. The roof bolter is now ready to tram. Slowly depress the foot pedal in the intended direction of travel.

NOTICE THE ROOF BOLTER CAN BE STOPPED AT ANY TIME IN CASE OF AN EMERGENCY

BY STRIKING THE PANIC BAR. BE PREPARED FOR A SUDDEN STOP WHEN THE PANIC BAR IS STRUCK. NOTE: While tramming the following precautions should be observed.

A. Operator must be positioned fully within the confines of the cab in order not to take the risk of getting caught between machine and rib or other obstacle.

B. Trailing cable must be handled with care.

C. Alert other workers of intentions.

D. Face direction of travel.

E. Maintain adequate clearance between machine and rib.

F. Know physical conditions of route.

G. Be especially cautious when rounding corners.

CAUTION DO NOT PERMIT THE BUILD-UP OF MUD OR OTHER MATERIAL TO COLLECT UNDER OR AROUND THE CABLE REEL. 15. Be careful not to damage trailing cable while tramming. Turn cable reel control to “ON” when picking up cable; turn cable reel control “OFF” when paying out cable.

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DRILLING CAUTION NEVER EXCEED THE DRILL ROD MANUFACTURER'S RECOMMENDATIONS FOR DRILL TORQUE AND THRUST. EXCESSIVE TORQUE AND THRUST CAN CAUSE THE DRILL ROD TO BUCKLE OR BREAK, THEREBY CREATING A HAZARD FOR PERSONNEL IN THE VICINITY OF THE ROOF BOLTER.

CAUTION DURING DRILLING AND BOLTING OPERATIONS OPERATOR MUST WATCH DRILL ROD AND REGULATE BOOM FEED CONTROL TO PREVENT DRILL ROD BUCKLING.

WARNING DURING DRILLING AND BOLTING OPERATIONS OPERATOR MUST REMAIN UNDER DRILL STATION CANOPY AT ALL TIMES.

NOTICE IF YOU ARE NOT SURE HOW MUCH DUST IS IN THE DUST COLLECTOR TANKS, EMPTY THE TANKS. DO NOT OVERLOAD THE DUST COLLECTOR CAPACITY. 1. Be sure the dust collection system is operating efficiently before proceeding to drill.

2. Position machine for drilling/bolting cycle.

3.

A. Lower cradle to floor BEFORE setting support arm to floor.

B. Keep support arm control lever in “UP” position to maintain roof contact while drilling.

C. Center cradle control lever.

4. Lower drill boom to floor.

5. Insert the 12” spotter drill, provided with your machine, into the drill chuck by grasping drill just below the bit.

6. Release your hold on the spotter drill.

7. Place one hand on the drill feed control lever. Place other hand on the fast feed control lever.

Raise the drill to about one foot from mine roof using the fast feed. Then raise the drill to contact with the roof using slow feed.

8. Move your hand from the boost lever to the rotation lever. Start rotation.

9. Drill a “spotter” or pilot hole two or three inches deep. Then reverse the boom feed lever to lower the drill out of the hole.

10. When the spotter drill clears the hole, stop rotation.

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CAUTION THE SPOTTER DRILL IS THE ONLY DRILL WHICH MAY BE SAFELY ROTATED COMPLETELY OUT OF THE HOLE. STOP ROTATION ON ALL OTHER DRILLING BEFORE COMING OUT OF THE HOLE. 11. While maintaining the downward travel of the boom, shift your hand from the rotation control lever to the fast feed control lever.

12. Continue the boom's downward travel until the drill box is nearly touching the floor. Then center both boost and feed control levers.

13. Remove the spotter drill.

CAUTION EXAMINE DRILL ROD FOR DEFECTS; DO NOT USE A DRILL ROD THAT IS BENT OR DAMAGED. 14. Examine drill rod for defects; do not use a drill rod that is bent or damaged. lnsert drill rod in drill chuck.

15. Guide the drill rod while slowly elevating the drill boom. As the bit nears the roof, reduce the boom elevating speed to a very slow rate so you can easily guide the bit into the pilot hole.

BE VERY CAREFUL OF YOUR HANDS AT ALL TIMES. 16. Continue to feed very slowly until the bit reaches the top of the pilot hole. Do not jam the bit.

Center the feed control lever. The drill rod is now retained at both ends: the base in the drill chuck, and the bit end in the pilot hole.

17. With one hand on the feed control lever and the other hand on the rotation control lever, you are now ready to start drilling in a normal, safe fashion.

WARNING NEVER GRASP ANY OBJECT WHEN IT IS ROTATING IN THE DRILL BOX.

Judging the proper feed rate requires some experience. Too little feed rate can cause rapid bit wear by permitting the bit to be ground by the rock rather than the bit penetrating and cutting the rock.

Too high a feed force, with relief pressures to high, can cause the drill rod to buckle.

Remember, buckling is most likely to occur when drilling is started with most of the full length of the drill rod exposed. As the drill penetrates into the roof, the wall of the hole stabilizes the drill rod, and a gradual increase in feed force can safely be provided to achieve maximum drilling rates.

Too high a feed force in soft rock can cause the bit to bite too deeply; if relief pressure is set to high, the bit shank or drill rod may be twisted off. With rotation relief set properly, the drill rotation will stall when feed is to high.

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In soft rock, too high a feed rate may permit the drill penetration to run ahead of the dust collector. This condition is easy to diagnose. You will notice intermittent bursts of dust around the drill rod at the hole. This condition is called "puffing”.

Another symptom of too high a feed rate in soft rock, beyond the collection capability of the dust system, is called “plastering”. In this condition, the drill cuttings not pulled into the drill rod are packed or plastered against the wall of the hole under the bit. With the "plastered” hole under the bit smaller than the bit, it can be very difficult to remove the drill rod from the hole. It is very particularly difficult to remove extensions.

18. When the drill penetration nears the boom feed stops, or when the desired drill depth is reached, reverse feed direction. Maintaining rotation while lowering the drill boom helps to clean the hole. However, stop rotation before the drill rod is completely out of the hole.

WARNING IT IS IMPORTANT TO STOP ROTATION BEFORE THE DRILL IS OUT OF THE HOLE TO AVOID WHIPPING OF THE DRILL ROD AS IT ROTATES CLEAR OF THE HOLE. THE DRILL CHUCK WILL PREVENT THE DRILL ROD FROM BEING HURLED, BUT IF YOU ARE NOT STANDING CLEAR YOU COULD BE STRUCK BY THE WHIP CIRCLE OF THE DRILL ROD. ALSO, THE WHIPPING DRILL ROD MAY BE CUT OR SCORED

BY THE WHIPPING MOTION. SCORING WILL PROVIDE A WEAK SPOT ON THE DRILL ROD. It is good practice to reverse drill feed just short of the boom stops. If the drill feed is stopped by the boom stops, the continued rotation will dull the bit by grinding against the back of the hole.

19. With rotation stopped, grasp the drill with one hand while continuing to lower the drill boom.

Continue the down travel of the boom to provide all available clearance for installing extension sections or the roof bolt.

EXTENSION STEELS SELECTION 1. Extension steels, two or more sections, are required when the desired drilling depth exceeds the available feed length of one section of the drill. The extension sections consist of the following: A. Driver - The section which has the 1 1/8” square base to fit the roof bolter drill box chuck.

B. Lead Extension - The section which has provision for bit attachment. At the end opposite the bit, the lead extension has a coupling arrangement which connects to the driver.

C. Middle Extension - One or more used when desired drilling depth exceeds the depth which can be obtained with driver and lead extension. This piece has a coupling arrangement, one end male, the other end female, to connect driver to lead extension.

2. Where extension steels are required, it is important to use the longest extension section lengths which will clear within the hole length obtained with the starter and the top of the roof bolter drill box.

Note: Use of the longest lengths of sections which will clear may eliminate the need for an additional middle extension to obtain the desired drilling depth.

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3. When planning for drill steel lengths to be used with the Long-Airdox Roof Bolter, several factors should be considered.

A. Starter length - Mining height minus 12”. The 12” allows for the height of the standard drill box, length of drill drive shank, and working clearance.

B. Driver length – DBT AMERICA recommends the driver length to be 6” less than starter length.

C. Lead and Middle Extension Length - Mining height less 18” is recommended.

DRILLING WITH EXTENSION STEELS 1. Insert “driver” into drill chuck.

2. Insert "lead extension” into hole and push upward until the base of the lead extension clears the top of the driver.

3. Line up and couple lead extension and driver.

WARNING DO NOT USE MACHINE POWER TO ROTATE DRIVER INTO ALIGNMENT WITH LEAD EXTENSION.

NOTICE BIT SIZING IS IMPORTANT. THE FOLLOWING INFORMATION ON BIT SIZING IS PROVIDED ONLY AS A GENERAL GUIDE. SPECIFIC REQUIREMENTS WILL VARY WITH MINE CONDITIONS. BE SURE TO CHECK WITH MSHA AND STAFF OFFICIALS TO BE SURE THAT YOUR BOLTING OPERATION IS PERMISSIBLE. To facilitate manual insertion and removal of extensions, it is common practice to use a larger bit on the starter steel than is used on the lead extension. For 1 3/8” expansion shells used with mechanical bolts, it is generally permissible to use 1 1/2” starter steel bit (or starter bit). For 1” resin bolts, it is usually permissible to use 1 1/32” starter bit.

Bit suppliers usually paint the starter bit and lead extension bit (finisher bit) different colors. In addition, the bit size is usually forged into the bit body. Another identification required by MSHA is provided at the base of the bit shank. The starter bit has a flat shank base; the finisher has a pyramid at the shank base.

It is important to use only the finisher bit for the upper portion of the hole because the anchorage provided by either expansion shells or resin is dependent on the proper size hole.

Even though resin bolts usually anchor over the full length, the upper anchorage is considered the most important.

Where one or more middle extensions are required, bit sizing is very important to the ease of removal of the middle and lead extensions. Worn bits drill smaller holes than new bits. If you have drilled a portion of the hole with a worn bit and it is necessary to change for the remainder of the desired hole depth, be sure to ream the “worn bit hole” with the new bit. The worn bit hole can be reamed with the new bit by providing full rotation speed and feeding slowly to the back of the hole.

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You can force the new bit to the back of the hole with machine power, but you cannot force the bit out of the hole since extensions do not couple rigidly. Therefore, be sure to ream the hole first.

It may be permissible to use three bit sizes where multiple extensions are required. Consult your bit supplier for advice in this matter. They may recommend 1 5/8” starter, 1 1/2” intermediate, and finally 1 3/8” for the finisher when standard expansion shells are used with long bolts.

4. With expansion and driver coupled, move your hands back to the feed and rotation controls.

As instructed previously, ease both controls in starting both rotation and feed.

You will be elevating the drill steels through a few inches of previously drilled hole, so approach the back of the hole with the bit gradually - Do not jam the bit.

Proceed with drilling as described previously.

5. As was described with the starter steel, when extension drills near the boom feed stops or when the desired drill depth is reached, reverse feed direction. Maintain rotation while lowering the drill boom until the extension coupling joint is out of the hole several inches.

Stop rotation and stop boom down travel. Grasp the extension with one hand and grasp boom feed control with the other hand.

Lower the drill boom pulling the driver out of the extension coupling.

A. If the desired hole depth has been drilled, maintain your grip of the extensions with one hand while removing the driver from the drill chuck with the other hand.

B. If additional hole depth is required, maintain your grip of extensions with one hand while picking up and coupling middle extension with other hand.

With both hands, lift drill string up into the hole until base of middle extension clears the top of the driver.

Release one hand and line-up driver with extensions. Ease extensions down out of the hole engaging coupling with driver.

CAUTION BE CAREFUL OF YOUR HANDS! DRILL STEEL EXTENSIONS ARE HEAVY. DO NOT PUT YOUR HANDS OR FINGERS BETWEEN THE END OF THE EXTENSIONS IN THE HOLE AND THE TOP END OF THE DRIVER. IF STEELS HANG IN THE HOLE, THEY CAN RELEASE AND DROP AT ANY TIME!

If you have problems with hanging steels, review the instructions previously presented. The more common causes and remedies have been outlined to keep the drill sections free from hanging in the hole. However, if water and voids are encountered in your roof drilling conditions, additional steps may be required to keep the drill steels free.

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DUAL RELIEF VALVE FUNCTION The dual relief valve (Figure 24) provides a means of limiting both drill feed force and drill rotation torque. Its purpose is to help torque all roof bolts correctly, equally, and safely.

DUAL RELIEF FIGURE 24 The dual relief valve consists of two individual relief valves enclosed in the same housing.

Depending on the position of the control lever, either both valves are in service or neither valve is in service.

LIMITING TOROUE - When the dual relief valve is “ON” drill rotation is limited by the relief valve in the drill rotation circuit. This valve is factory-set so the drill rotation drill output is 190 ft. lbs.

The relief valve setting will be approximately 950 PSI at this torque. When the relief valve opens, it causes a two-way valve to open and connect the drill rotation circuit to tank. The use of the pilot operated two-way valve allows smoother, more accurate operation than would be provided by a relief valve alone. The setting of the relief valve can be adjusted to meet individual mine conditions.

LIMITING THRUST - Drill thrust is regulated by the remaining relief and two-way valve combination, connected in the boom elevation circuit. The thrust with which the bolt is held against the bearing plate at the roof is important for maintaining consistent bolt torques. If the operator uses too much thrust, much of the torque is lost to friction. If the operator does not use enough thrust, the bolt can pull itself out of the chuck.

The use of the dual relief valve helps avoid both of these problems. When brought into use, the thrust control side of the dual relief will dump at about 150 PSI. This setting is usually high enough to maintain good bolt-chuck contact. The thrust control setting can also be adjusted to meet individual mine conditions.

USE MECHANICAL FUNCTIONS - Keep dual relief valve in “OFF” position while drilling hole. In this position, valve allows enough torque and thrust to achieve maximum penetration rate.

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Turn dual relief valve “ON” before starting rotation to install bolt. Valve helps keep all bolts torqued equally.

RESIN BOLTS - Turn dual relief valve “ON” while drilling hole. Valve limits torque and thrust to help prevent the smaller diameter drill rod from buckling and creating a hazard.

Turn dual relief valve “OFF” before installing bolt. In this position, valve allows enough thrust to push pin through resin cartridge and enough torque to mix resin.

NOTICE THE DUAL RELIEF VALVE IS PRESET AT THE FACTORY FOR DRILLING WITH 1 1/8” DIAMETER DRILL ROD UNDER NORMAL CONDITIONS. IT WILL USUALLY BE NECESSARY TO LOWER THE "THRUST" PRESSURE SETTING WHEN WORKING WITH THE SMALLER DIAMETER DRILL ROD USED IN RESIN BOLTING. IT IS VERY IMPORTANT THAT BOTH SIDES OF THE DUAL RELIEF VALVE BE SET FOR THE TYPE OF BOLTING SYSTEM AND THE ROOF CONDITIONS WHERE THE ROOF BOLTER IS BEING OPERATED.

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DRILL OPTIONS AND ADJUSTMENTS NOTICE BE SURE YOUR ROOF BOLTER IS SET UP AND ADJUSTED FOR YOUR CONDITIONS. Since conditions vary extensively from mine to mine, or even between mine sections, DBT America recommends that you contact your Service Supervisor to be sure the roof bolter hydraulic pressures correspond safely to the ratings or specifications of your drilling tools.

Soft drilling usually requires high rotation speed and low feed force. Hard drilling conditions require just the opposite: slower rotation speed and higher feed force. DBT America provides as standard a rotation speed of approximately 475 RPM and feed hydraulic pressure relief set to limit the feed force on the drill to about 2,000 lbs.

DBT America standard speed and feed force limits provides a range which suits most conditions where 1 3/8” holes are drilled in rock strata which vary in hardness. Most mining conditions require drilling through soft to medium-hard shales for several feet with about 2’ of harder rock to be drilled for good expansion sheel anchorage. The operators usually develop skills to achieve maximum penetration rates with reasonable bit wear.

If your conditions are consistently very soft drilling, your Service Supervisor may recommend replacement of the hydraulic drive unit for the drill rotation to provide higher speed.

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INSTALLATION OF MECHANICALLY ANCHORED ROCK BOLTS Important factors toward successful mine roof support with rock or roof bolts should be remembered and practiced by the roof bolter operators.

1. Roof bolts support mine roof in two principle ways: A. With the expansion shield anchored in a firm rock, the bolt suspends weaker rock layers which rest on the bearing plate and cap (header, half header, scab board, etc.) board.

B. With the expansion shell anchored in a firm rock and the bearing plate drawn against the rock at the roof line, the weaker rock layers are bound together to serve as a solid laminated beam.

2. In order for roof bolts to be effective roof support: A. The cut must be bolted as soon as possible after mining. The greater the delay the greater the roof layers have an opportunity to sag and separate.

B. The proper torque must be applied to the bolt (within a narrow range) to pre-tension the bolt and compress the rock layers. The torque applied to the bolt is prescribed by experience in your mining condition. The torque is usually determined by the quality of the anchorage rock.

C. All bolts must be torqued consistently. Otherwise, the high torqued bolts will carry all the loading. Consistent torque distributes the roof load over all the bolts evenly.

NOTICE IMMEDIATELY AFTER THE FIRST BOLT IS INSTALLED, CHECK FOR REQUIRED TORQUE READING WITH AN APPROVED CALIBRATED TORQUE WRENCH. READING SHOULD BE WITHIN LIMITS OF APPROVED ROOF CONTROL PLANS. CHECK EVERY FOURTH BOLT. IF TORQUE LIMITS CANNOT BE OBTAINED, OR IF BOLT ANCHORAGE IS DIFFERENT THAN NORMAL, NOTIFY YOUR SUPERVISOR IMMEDIATELY. 3. Roof bolts are inserted into the hole manually. Always use a bolt wrench which fits the drill chuck properly. Push the bolt into the hole manually far enough to insert the bolt head into the drill chuck.

WARNING NEVER USE THE ROOF BOLTER DRILL BOX ROTATION TO JOIN THREADED BOLT EXTENSIONS. While pushing the bolt toward the roofline, watch carefully to try to detect any side flexing which would indicate the shell is jamming and the bolt is about to buckle.

Important - When long plates or boards are used with the bearing plate as part of your bolt assembly, stop boom feed with the plate or board just short of the roof. Turn the plate or board to desired direction, remove your hand completely: then push on up solid with the roof.

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WARNING NEVER PLACE YOUR FINGERS BETWEEN THE BEARING PLATE OR BOARD AND THE ROOF. 4. Now that the bearing plate and bolt head are firmly contacting the mine roof, turn on dual relief valve (bolt torque control).

NOTICE THE BOLT TIGHTENING WRENCH IS RETAINED AT THE BASE BY THE DRILL CHUCK. THE TOP OF THE WRENCH IS RETAINED FIRMLY AGAINST THE ROOF

BY THE CONTACT WITH THE ROOF BOLT HEAD. THERE IS NO NEED TO HOLD THE WRENCH WHILE TIGHTENING THE BOLT. 5. With the bolt torque in the "ON” position, push in feed lever with one hand and with the other hand push in rotation lever to torque the bolt. Keep rotation engaged until the rotation stalls.

NOTICE THE DUAL RELIEF VALVE PROVIDES TWO FUNCTIONS. IT LIMITS ROTATION TORQUE TO THE PRESET VALUE REQUIRED FOR YOUR CONDITIONS. SECOND, IT LIMITS THE BOOM FORCE ON THE WRENCH TO A CONSISTENT LOW FORCE PROVIDED TO MAINTAIN FIRM CONTACT OF THE WRENCH AND BOLT HEAD. The boom force applied to the wrench is controlled so that the rotation torque is not absorbed in friction between wrench, bolt head, and bearing plate. Without the thrust control, it is nearly impossible to maintain consistency in bolt torques.

6. With the bolt installed, center rotation control and reverse feed control to "DOWN” direction.

With the drill boom lowered to about level position, center boom feed control.

7. Remove wrench.

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INSTALLATION OF FULLY GROUTED RESIN BOLTS 1. Resin bolt systems operate much as was discussed for mechanical bolts. However, resin bolts do not depend solely upon anchorage at a single point because the resin forms a bond between the bolt and all of the surrounding strata.

Resin bolt systems have proven to be effective in many mine roof conditions where mechanical bolts have failed.

However, procedures differ somewhat as specified by the various resin manufacturers.

Principle differences between resin manufacturers' procedures usually involve mixing time and the amount of time thrust is held on the assembly to permit setup.

Your resin supplier, and your DBT America Service Supervisor should be called in to assist in a safe transition from mechanical bolts to resin.

2. Drilling procedures provided previously apply to drilling for resin bolt installation. However, drill thrust and rotation torque must be set with relief limits within the mine tool suppliers recommendations. The small diameter drill steels commonly used for resin installation are very easily buckled.

3. Drilling thrust for drilling the 1” resin hole is often lower than thrust required to push the resin bolt into the resin cartridges. Likewise, rotation torque for drilling is often less than the torque required for mixing the resin after the bolt is inserted.

Your service supervisor can assist in setting up your roof bolter so that resin hole drilling is done with the dual relief on. The dual relief (normally used for mechanical bolt installation) can be set for boom thrust and rotation torque limits corresponding to limits of your drilling tools.

When installing the resin bolt, turn the dual relief "OFF”. Higher boom thrust and rotation torque (provided by system relief settings) is then available for inserting the pin and then mixing the resin.

4. Following are general procedures for installing resin bolts. provided by your resin supplier.

Specific instructions must be

A. After hole has been drilled, insert wrench in drill chuck.

NOTICE HOLE DEPTH IS VERY CRITICAL WITH RESIN BOLTS. THE DEPTH MUST BE LONGER THAN THE BOLT BUT NO MORE THAN 1 OR 2 INCHES LONGER.

NOTICE THE WRENCH USED FOR RESIN BOLT INSTALLATION SHOULD BE NO LONGER THAN NECESSARY TO CLEAR WITHIN THE DRILL CHUCK, AND THE WRENCH SURFACE MUST REACH THE ROOF LINE. DBT AMERICA RECOMMENDS AN OVERALL WRENCH LENGTH 12 INCHES.

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B. Insert necessary resin cartridges into the hole.

C. Insert the resin bolt head into the wrench. It is helpful if the boom elevation is preset so that there is just enough clearance to insert the resin bolt. The upper end of the resin bolt is then positioned under the hole, and you can permit the resin cartridge to slip out of the hole and rest on top of the bolt.

Guide the bolt with one hand while slowly elevating the boom. When the bolt end is started in the hole, release your hold on the bolt.

D. Push the bolt into the hole. Watch for any indication of bowing of the bolt which is a warning of buckling. If no bowing is observed, continue pushing the bolt to a point with the bearing plate 1/2’ to 1” below the roof line. Center boom elevation control.

E. Rotate the bolt for fifteen to twenty seconds at about half rotation speed (200 to 250 RPM).

F. Stop rotation; push the bolt upward solid against the roof and hold for the time specified by the resin manufacturer.

G. Lower the boom; remove the wrench; turn dual relief to "ON” position ready for drilling the next hole.

CAUTION RESIN MAY CAUSE SKIN IRRITATION TO SOME PEOPLE. YOU MIGHT CONSIDER THE USE OF LONG SLEEVE CLOTHING, GLOVES, AND A FACE SHIELD IN ADDITION TO SAFETY GLASSES WITH SIDE SHIELDS.

WARNING A RESIN BOLT, USUALLY MADE FROM CONCRETE REINFORCING ROD MATERIAL, HAS PROJECTIONS ALONG ITS LENGTH. THESE ARE REQUIRED FOR EFFICIENT RESIN MIXING AND FOR AN EFFECTIVE BOND BETWEEN THE RESIN AND THE BOLT. UNDER NO CIRCUMSTANCES ATTEMPT TO HOLD A ROTATING BOLT. SEVERE INJURY OR DEATH COULD OCCUR.

WARNING SPECIAL CARE SHOULD BE EXERCISED WHEN WORKING WITH THE BENDABLE RESIN BOLTS USED IN LOW COAL. BE SURE TO FOLLOW BOLT AND RESIN MANUFACTURER'S RECOMMENDATIONS.

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RB2-88 ROOF BOLTER

DBT AMERICA

SHUTDOWN PROCEDURE The roof bolter must be properly shutdown before leaving the area or before performing any maintenance or service. Some maintenance or service procedures may require additional steps to insure the safety of the maintenance personnel working on or around the machine and will be listed in the maintenance section of this guide.

1. Park the roof bolter in its designated parking area out of traffic, on flat, solid ground. if it is not possible to park the machine on flat ground, park the machine at a right angle to the slope.

WARNING ALWAYS CHECK BEFORE LOWERING THE CRADLES, BOOMS, AND THE SUPPORT ARMS TO MAKE SURE NO ONE HAS ANY PART OF THEIR BODY NEAR MOVING PARTS OF MACHINE.

CAUTION THIS UNIT IS EQUIPED WITH A TRAM STATION CANOPY. BE CAREFUL NOT TO HIT YOUR HEAD WHEN ENTERING THE TRAM STATION. 2. Completely lower cradle and booms to the bottom.

3. Completely lower support arms.

4. Relieve hydraulic pressures and set control levers to neutral.

5. Properly tend to trailing cable.

6. Turn circuit breaker lever to "OFF” position.

7. Turn power "OFF” at main distribution box.

8. Immediately report any defects or unsafe conditions to your supervisor.

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SAFETY PRECAUTIONS FOR UNDERGROUND OPERATION In addition to the preceding instructions for operating the roof bolter, observe the following special precautions after the roof bolter is taken underground.

1. Communication is a key element in maintaining safety. Exact instructions and warnings should be given to, and thoroughly understood by each workman. Good communications between the entire crew must be maintained throughout the shift.

2. Check the condition of the trailing cable before turning power on at the power source.

3. This machine must be maintained in a permissible condition, following all state and federal laws.

4. Make a visual check of the roof bolter before energizing. Look for loose bolts, covers, locking devices, damaged parts, and cracked or broken lenses. Any part of the machine which does not function properly is a hazard. Report it immediately to your immediate supervisor.

5. Prior to operation, make sure the working area is safe. Make a visual inspection of roof and ribs and take all steps necessary to insure safety.

GENERAL DRILLING AND BOLTING SAFETY 1. Before beginning the drilling or bolting operation, carefully pay out the trailing cable and provide enough slack in the cable to allow adequate clearance and safe maneuverability.

WARNING EXPOSING ANY PART OF YOUR BODY FROM UNDER THE DRILL STATION CANOPY DURING DRILLING OR BOLTING OPERATIONS CAN CAUSE SEVERE INJURY OR DEATH. KEEP ARMS, LEGS, AND HEAD UNDER DRILL STATION CANOPY.

WARNING DO NOT OPERATE ROOF BOLTER WITHOUT DRILL STATION CANOPIES. OPERATING WITHOUT DRILL STATION CANOPIES CAN RESULT IN SEVERE INJURY OR DEATH.

TRAMMING SAFETY RULES 1. Communicate your intentions to the workmen affected by the movement of the roof bolter.

2. Check the position of the trailing cable to be sure there is sufficient slack to finish the operation.

3. Note the condition of the roadways and physical surroundings of the route.

4. Position the cradles, booms, and support arms for tramming.

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5. Position your body completely inside the operator's compartment, facing the intended direction of travel.

6. Position the roof bolter in the center of the roadway to allow maximum safe clearance.

Consistently maintain clearance, which is critical to the safe movement of the roof bolter.

7. Be especially careful when tramming for long distances, through intersections, in narrow entries, or over uneven bottoms.

8. Remember that careless operation of a roof bolter can lead to roof falls or accidents.

9. Always stop and check behind before passing through ventilation curtains to avoid hitting other machinery or workmen on the other side of the curtain.

10. Because of limited visibility, be especially careful when turning corners.

SHUTTING DOWN THE ROOF BOLTER 1. At the end of the shift, park the roof bolter at a designated parking area. Provide sufficient clearance and avoid parking the roof bolter near ventilation curtains where collisions with workmen or other equipment might result.

2. Properly shutdown the roof bolter (see Shutdown Procedure, page 43).

45

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RB2-88 ROOF BOLTER

HAZARD ZONE FIGURE 25

46

RB2-88 ROOF BOLTER

DBT AMERICA

TOWING A DISABLED MACHINE WARNING IT IS NOT POSSIBLE, WITHIN THE SCOPE OF THIS GUIDE, TO ANTICIPATE ALL POSSIBLE ARRANGEMENTS FOR TOWING A DISABLED UNIT. BEFORE ATTEMPTING TO TOW ANY VEHICLE, YOU MUST TAKE ALL POSSIBLE PRECAUTIONS TO PROTECT THE OPERATORS AND ANY ONE AROUND BOTH VEHICLES FROM BEING INJURED BY EITHER THE TOWING VEHICLE, THE TOWING DEVICES OR THE VEHICLE BEING TOWED. THE PRIMARY TOWING DEVICE USED (CABLES, BARS, ETC.) AND THE TOWING VEHICLE (SCOOP, TRACTOR, ETC.) MUST BE STRONG AND HEAVY ENOUGH TO MAINTAIN CONTROL OF BOTH VEHICLES THROUGH ALL BOTTOM CONDITIONS TO BE ENCOUNTERED AT ALL TIMES. SAFETY CHAINS OR OTHER SAFETY DEVICES MUST BE USED IN CASE OF FAILURE OF THE PRIMARY TOWING DEVICE. ALL OPERATORS MUST BE ALERT AT ALL TIMES TO PREVENT EITHER UNIT FROM "RUNNING AWAY" OR RUNNING OUT OF CONTROL DURING TOWING. 1. Couple the towing vehicle securely to the disabled vehicle.

2. Rotate all four torque hubs on the roof bolter to the free wheeling position.

WARNING AT NO TIME DURING TOWING SHOULD ANYONE RIDE IN OR ON THE VEHICLE BEING TOWED OR STAND IN BETWEEN THE TOWING VEHICLE AND THE DISABLED VEHICLE. 3. Begin towing the vehicle 4. Once the destination is reached, stop both vehicles and chock in both directions at all four wheels of the disabled vehicle for additional stability. Rotate all four torque hubs back to the drive position.

WARNING FAILURE TO CHOCK ALL FOUR WHEELS ON THE DISABLED VEHICLE BEFORE REMOVING THE TOWING DEVICE COULD ALLOW THE DISABLED VEHICLE TO ROLL AWAY UNCONTROLLED.

47

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RB2-88 ROOF BOLTER

48

RB2-88 ROOF BOLTER

DBT AMERICA

SECTION 3 GENERAL MAINTENANCE INSTRUCTIONS Long reliable service and the safety of those working with this Roof Bolter can only be ensured by conscientious periodic maintenance of the machine.

Anyone performing maintenance on this machine should be trained to operate it and must be familiar with this DBT AMERICA Guide.

All electrical work must be supervised and inspected by a MSHA certified electrician.

BEFORE MAINTENANCE OR SERVICING: 1. SHUTDOWN the roof bolter on level ground (see Shutdown Procedure page 43).

2. Disconnect the power. The circuit breaker must be in the "OFF" position. If work is to be done inside the electrical connection box, the power should be disconnected.

3. Test the controls to be sure that the roof bolter will not operate.

4. Chock all four (4) wheels in both directions.

During maintenance or servicing, if the drive motors are to be run, the roof bolter must be jacked clear of the ground and securely blocked. All four wheels must be free to rotate.

DO NOT perform maintenance in a congested area. This could endanger the maintenance person or others in the vicinity. The maintenance area should be as clean as possible.

Whenever a potential problem is uncovered during a periodic maintenance check, it is imperative that it be corrected immediately by a qualified service person.

CLEANLINESS cannot be overemphasized as the essential ingredient of a good maintenance program. Machines should be kept as free as possible of dirt and debris which could impede performance or infiltrate systems and cause premature wear or failure.

WARNING DO NOT MOVE ANY HYDRAULIC CONTROL LEVER UNLESS YOU ARE CERTAIN THAT NO ONE COULD BE HURT BY THE MACHINE'S MOVEMENT. DO NOT DISCONNECT A HYDRAULIC CIRCUIT FROM A CYLINDER WHILE THERE IS LOAD ON THE CYLINDER. DISCONNECT THE POWER BEFORE WORKING ON ANY PART OF THE ELECTRICAL SYSTEM.

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MAINTENANCE CHECK LIST (For Specific Instructions, See Page 51) (For Lubricant Specifications, See Pages 66 And 67) (For Lubrication Chart, See Page 64)

ITEM OR LOCATION EVERY SHIFT Electrical Cables And Conduits; Hydraulic Hoses And Fittings; Tires; Lights; Warning Tags; Reflectors Operation Of All Switches, Panic Bars And Hydraulic Controls Hydraulic Oil Level Hydraulic Oil Filter Indicators Drill Box Cradle, Boom And Support Arm Assembly Auger Retainer (Optional) Drill Bit Condition Dust System Cable Reel First Bolt Installed DAILY Blower Belts Hinge Pins, Jack Pins, Jack Anchors And Sliders Entire Machine (Nuts And Bolts) Auger Retainer (Optional) Blower Cable Reel Cradle, Boom And Support Arm Assembly Drill Box Torque Hubs Fire Suppression Turntable Roller

INSPECT

ADJUST

CHANGE

LUBRICATE

• •

A/R

• • • • • • • • •

A/R

• •

A/R

• • • • • • • • •

WEEKLY Hydraulic Pressure Settings Electrical System Trailing Cable Cable Reel (Drive Chain) Drill Box Explosion Proof Housings Tires And Wheel Mounting Bolts

• • • • • • •

EVERY THREE MONTHS Blower Torque Hubs Electric Motor

• • •

EVERY SIX MONTHS Hydraulic Fluid Pumps

•

A/R A/R A/R

A/R A/R A/R A/R •

A/R A/R A/R

• A/R A/R A/R

A/R • A/R

A/R A/R • • • •

YEARLY Cable Reel A/R - Perform service as required.

A/R •

50

• • • • •

RB2-88 ROOF BOLTER

DBT AMERICA

PERIODIC MAINTENANCE PROCEDURES EVERY SHIFT

CAUTION DO NOT ALLOW WATER TO ENTER THE ELECTRICAL CONTROLLER AT ANY TIME DURING SERVICE OR MAINTENANCE, THE CONTROLLER COVER SHOULD BE IN PLACE AND SECURED.

WARNING DO NOT DISCONNECT A HYDRAULIC CIRCUIT FROM A CYLINDER WHILE THERE IS LOAD ON THE CYLINDER. DISCONNECT THE POWER BEFORE WORKING ON ANY PART OF THE ELECTRICAL SYSTEM. \

1. Wash down the roof bolter and remove all foreign material from the operator's compartment and drill station work areas.

2. Check torque on installed bolts with a torque wrench of known accuracy. if torque is consistently too high or too low, reset the dual relief valve (Figure 26). If torque varies erratically, check dual relief valve for proper operation and cleanliness. Also make sure hydraulic system oil is clean.

DUAL RELIEF FIGURE 26 3. Check drill bit condition (replace worn drill bits).

4. Inspect all electrical cables, conduits, hydraulic hoses, fittings, tires, and lights for signs of wear or damage. Repair or replace any found damaged.

5. Visually inspect the condition and readability of all warning tags, labels, and reflectors.

Replace any found missing or damaged.

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6. Inspect the dust system (Figure 27).

A. Inspect hoses and fittings and replace any found damaged.

B. Clean-out dust boxes and inspect filter (replace if required).

C. Inspect blower drive belt (replace or adjust if required).

D. Check suction at drill chuck with vacuum gauge.

DUST SYSTEM FIGURE 27

WARNING DO NOT MOVE ANY HYDRAULIC CONTROL LEVER UNLESS YOU ARE CERTAIN THAT NO ONE COULD BE HURT BY THE MACHINE'S MOVEMENT. 7. Check the operation and condition of all hydraulic controls.

8. Check the operation and condition of all hydraulic controls.

9. Check the auger-retainer (optional) condition . Make sure mounting bolts are tight and there are no cracks or excessive wear in the assembly.

10. Visually inspect cradles, booms, support arms, and drill boxes condition for cracks or excessive wear.

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RB2-88 ROOF BOLTER

DBT AMERICA

11. Check the hydraulic oil level (Figure 28) by looking at the sight glass located on the frame behind the right rear wheel. (For Fluid Specifications see pages 66 and 67).

HYDRAULIC OIL LEVEL FIGURE 28 12. Check the hydraulic oil filter indicators (Figure 29). The hydraulic oil filters are located below and between the valve banks on each drill boom. The filter indicator remains clear as long as the element is not restricted. Once the element becomes restricted, the indicator will turn red, indicating the element is clogged and requires changing. After changing the element, the indicators button must be reset by pushing in on the button.

HYDRAULIC OIL FILTER FIGURE 29

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RB2-88 ROOF BOLTER

13. Check the operation and condition of all switches and panic bars (Figure 30).

PANIC BARS AND SWITCHES LOCATION FIGURE 30 14. Inspect cable reel (Figure 31) for build-up of mud or other material under or around the reel.

CABLE REEL INSPECTION FIGURE 31

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RB2-88 ROOF BOLTER

DBT AMERICA

DAILY 1. Check blower belt condition and tension (Figure 32). Replace worn belts and readjust tension as required.(Tension should be adjusted to a maximum of 1” deflection). Check oil level in blowers as indicated on Lubrication Chart (Figure 47, page 64).

BLOWER BELT ADJUSTMENT FIGURE 32 2. Inspect all hinge pins, jack pins, jack anchors, and sliders for excessive wear or cracks.

Lubricate points as indicated on Lubrication Chart (Figure 47, page 64).

3. Visually inspect the entire machine, checking for loose nuts or bolts. Pay particular attention to high stress areas.

4. Check the auger-retainer (optional) condition, make sure mounting bolts are tight and that there are no cracks or excessive wear in the assembly. Lubricate points as indicated on Lubrication Chart (Figure 47, page 64).

5. Lubricate cable reel stub shaft, drive gear and spooler (Figure 33). Lubricate points as indicated on Lubrication Chart (Figure 47, page 64).

CABLE REEL LUBRICATION FIGURE 33 6. Lubricate cradle, boom, and support arm assemblies. Lubricate points as indicated on Lubrication Chart (Figure 47, page 64).

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7. Visually inspect drill box for excessive wear or oil leakage. Check oil level (Figure 34) and lubricate points as indicated on Lubrication Chart (Figure 47, page 64).

DRILL BOX LUBRICATION FIGURE 34 8. Check the fire suppression system.

A. Inspect the hoses, fittings, and nozzles and replace any found damaged.

B. Check the extinguisher tanks (Figure 35) for signs of damage or corrosion.

C. Check the nozzle openings. The slot should be packed with silicone grease. If the nozzles are open or need to be repacked, the lines should be checked for blockage and blown clear before repacking them with silicone grease.

D. Remove the fill cap (Figure 35).

E. Check that the extinguisher is filled with free-flowing Ansul multi-purpose A,B,C dry chemical to a point not more than 3” from the bottom of the fill opening.

F. Replace the fill cap.

FIRE SUPPRESSION TANK AND NOZZLE FIGURE 35

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RB2-88 ROOF BOLTER

DBT AMERICA

9. Inspect torque hubs and Check oil level (Figure 36). (For Lube Specifications see pages 66 and 67).

TORQUE HUB OIL LEVEL FIGURE 36 10. Inspect the turntable roller (Figure 37) and lubricate as indicated on Lubrication Chart (Figure 47, page 64).

TURNTABLE ROLLER INSPECTION FIGURE 37

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WEEKLY 1. Check hydraulic pressure settings and condition of suction hoses of pumps. damaged or worn hoses and readjust pressure setting if necessary.

Replace

WARNING ELECTRICAL SYSTEM REPAIRS MUST BE PERFORMED OR SUPERVISED BY AN MSHA CERTIFIED ELECTRICIAN. 2. Check electrical system for permisibility.

3. Unreel the entire trailing cable and carefully check its condition. Replace trailing cable if excessively worn or damaged.

4. Inspect, clean, and lightly oil cable reel drive chain (Figure 38).

CABLE REEL DRIVE CHAIN LUBRICATION FIGURE 38 5. Check the tires and wheel mounting bolts (Figure 39). The mounting bolts should be torqued to 130 ft. lbs. If equipped with pneumatic tires, check the tire pressure and condition.

WHEEL MOUNTING BOLTS FIGURE 39

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DBT AMERICA

WARNING EXTREME CAUTION MUST BE OBSERVED WHEN WORKING INSIDE THE ELECTRICAL CONTROLLER TO PREVENT ELECTRICAL SHOCK. YOU MUST FOLLOW THE SAFETY PROCEDURES LISTED AT THE BEGINNING OF THIS SECTION (PAGE 49).

6. Remove covers on explosion proof housings (Figure 40). Make sure that all connections are tight and that housing interiors are clean and dry. When replacing covers, be sure to check for permissible fit.

EXPLOSION PROOF HOUSINGS FIGURE 40 7. Drain and replace oil in drill boxes (Figure 41).

A. Fill drill box with clean light mineral oil.

B. Run gear box for five minutes.

C. Drain and refill with correct oil (see pages 66 and 67 for Lube Specifications).

DRILL BOX LUBRICATION FIGURE 41

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EVERY THREE MONTHS 1. Lubricate blower (Figure 42) until clean grease flows from operation relief valve.

BLOWER LUBRICATION FIGURE 42 2. Inspect the electric motors (Figure 43).

A. Be sure the machine circuit breaker is in the “OFF” position.

B. Remove the inspection covers.

C. Inspect the windings, commutators, brushes, armature, and terminal leads. Lubricate the electric motors as indicated on the Lubrication Chart (Figure 47, page 64).

ELECTRIC MOTORS FIGURE 43

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DBT AMERICA

3. Replace oil in the torque hubs (Figure 44).

TORQUE HUB OIL LEVEL FIGURE 44

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EVERY SIX MONTHS 1. Check flow on pumps with flowmeter (Figure 45).

HYDRAULIC PUMPS FIGURE 45 2. Drain hydraulic tank and replenish with fresh oil (for Lube Specifications see pages 66 and 67).

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DBT AMERICA

YEARLY 1. Inspect cable reel collecting rings, contactor points, brushes, and bearings (Figure 46). Clean and repack bearings when reel is disassembled.

CABLE REEL INSPECTION FIGURE 46

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LUBRICATION CHART FIGURE 47

64

RB2-88 ROOF BOLTER

Ref.

Location

DBT AMERICA

Lubricant

No. Of Places

Remarks

Frequency

1 2 3

Tram Mount Pivots Cylinders Hydraulic Oil Reservoir

Spec 100-3 Spec 100-3 Spec 100-1

2 4 1

4 5

Breather, Oil Reservoir Tram Drive Reducers Planetary

-------------Spec 100-6

1 2

6

Oil Filter

--------------

1

7

Blower (Drive End)

Spec 100-3

1

Grease Until Clean Grease Flows From Relief.

8

Blower (Gear End) Electric Motor

Spec 100-8 Spec 100-3

1 1

Spec 100-3

1

Spec 100-3

4

Light Coat Of Grease On Sliding Surfaces.

Every Shift

11

Grease Fitting On Cable Reel Flange Bearing Sliding Surfaces For Roof Support Tubes And Sumping Drill Box Cable Reel Drive Chain

Check Oil Level Lube Armature Bearings Through Grease Fitting On Ens Of Motor. Use 25cc Per End. Remove Fittings And Allow Motor To Run For At Least One Hour Then Reinstall Fittings.

See Note

2

Light Coat Of Lube

Weekly Periodically

12

Cable Reel Spooler Shaft

1

Light Coat Of Lube

Every Other Shift

13

Cable Reel Spooler Bearing Drill Box

Any Good Quality Chain Lube Dri-Slide Or Similar Dry Lube Spec 100-3

2

See Note

Every Other Shift Every Shift

9 10

14 15 16 17 18 19 20

21 22 23 24

Drill Box Carrier Pins Lift Arm Pin (Drill Boom) Leveling Bracket Pin Boom Arm Pin (Upper) Boom Arm Pin (Lower) Radius Arm/ATRS Pin Connecting Link Pin (Upper) Connecting Link Pin (Lower) Support Arm Pin Sliding Bearings For Drill Boom Base Pin Safety Arm Pin

See Note See Note 833 Liters Check Sight Gauge, Add Fluid If Necessary Clean Filter When Required Turn Wheel Unit Until Check & Fill Plugs Are At 3 & 9 O’clock, Then Remove Plugs.

Fill In One Plug Until Oil Flows From Second (Case Is Half Full).

25 Micron Element

40W Non Detergent Spec 100-3 Spec 100-3 Spec 100-3 Spec 100-3 Spec 100-3 Spec 100-3 Spec 100-3

1

Check Oil Level

4 2 4 2 2 2 2

See Note See Note See Note See Note See Note See Note See Note

Spec 100-3

2

See Note

Spec 100-3 Spec 100-3

1 4

See Note

Spec 100-3 Spec 100-3

1 2

See Note See Note

65

Every Shift

Every Other Shift

Each Shift As Necessary Every 250 Hours Of Operation Daily Every Three Months

Every Shift

DBT AMERICA

RB2-88 ROOF BOLTER

LUBRICANT SPECIFICATIONS SPEC. 100-1 - ANTI-WEAR HYDRAULIC OIL ASTM GRADE 315 SUPPLIER

BRAND NAME

SUPPLIER

BRAND NAME

1. AMOCO OIL CO.

AMOCO AW OIL NO. 68

2. GULF OIL 3. MOBIL OIL CORP.

HARMONY 68 AW MOBIL DTE-16

10. TEXACO LUBRICANTS CO. 11. EXXON 12. PENNZOIL

TEXACO RANDO OIL HD 68 NUTO H 68 PENNZBELL AW 68 HYDRAULIC OIL

4. CHEVRON U.S.A.

CHEVRON HYDRAULIC OIL AW ISO 68

13. STANDARD OIL CO. STD. OIL CO.OF OHIO BORON OIL CO BP OIL INC.

5. SUN OIL'COMPANY

SUNVIS 868

6. UNOCAL76

UNAX AW 68

14. LUBRICATION ENGINEERS 15. CONOCO INC.

7. SHELL OIL COMPANY

SHELL HYDRAULIC OIL #33 HULDRAULIC AW 68 CENTRAULIC AW 68 DURO AW S-315 OIL

8. CENTURY LUBRICATING OILS, NC. 9. ATLANTIC RICHFIELD CO.

INDUSTRON 53 INDUSTRON 53 ENERGOL HLP-C68 6120 MONOLEC HYD. OIL

16. HYDROTEX

SUPER HYDRAULIC OIL 68 SYSTEMS 5K 68

17. PHILLIPS

MAGINUS A OILS 81350

18. MINERS OIL

HYDRAULIC OIL 68AW

SPEC. 100-3 - EXTREME PRESSURE BEARING GREASE NLGI GRADE #2 1. AMOCO OIL CO 2. GULF OIL 3. MOBIL OIL CORP. 4. CHEVRON U.S.A. 5. SUN OIL COMPANY

6. UNOCAL 76 7. SHELL OIL COMPANY 8. CENTURY LUBRICATING OILS, INC.

AMOLITH GREASE 2 EP RYKON PREMIUM GREASE 2 EP GULFCROWN GREASE EP#2 MOBILUX EP-2

9. TEXACO, LUBRICANTS CO.

TEXACO MULTIFAK EP 2

10. EXXON

LIDOK EP 2

11. PENNZOIL

CHEVRON DURA-LITH GREASE EP-2 NLGI 2 SUN PRESTIGE 742EP

12. LUBRICATION ENGINEERS 13. CONOCO INC.

MULTIPLEX EP2 ALVANIA EP-2 HULLITH EP2 MULTIPURPOSE GREASE OR REPLEX 2 OR UNIWRL 2 OR UNIWRL EMB OR HULLITH GP 2 OR HULLITH EP 2

14. HYDROTEX 15. PHILLIPS 16. ATLANTIC RICHFIELD

PENNLITH EP 712 GREASE 3752 ALMAGARD VARIPURPOSE LUBRICANT EP CONOLITH GREASE NO. 2 OR SUPER STA GREASE NO. 2 LC-65 HYPLEX PHILUBE EP GREASE LITHOLINE H EP-2 GREASE

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RB2-88 ROOF BOLTER

DBT AMERICA

SPEC. 100-6 - EXTREME PRESSURE GEAR OIL (SAE 90) SUPPLIER

BRAND NAME

SUPPLIER

BRAND NAME

1. AMOCO OIL CO.

AMOCO AW PREMAGEAR EP 320

10. TEXACO LUBRICANTS CO.

2. GULF OIL 3. MOBIL OIL CORP.

EP LUBRICANT HD 320 MOBIL GEAR 632

11. EXXON 12. PENNZOIL

4. CHEVRON U.S.A.

CHEVRON GEAR COMPOUND EP ISO 320

13. LUBRICATION ENGINEERS

5. SUN OIL'COMPANY 6. UNOCAL76

SUNEP 320 EXTRA DUTY NL GEAR LUBE 6EP OMALA 75

14. CONOCO INC. 15. HYDROTEX

HULBEST EP-6

17. MINERS OIL

MEROPA 320 or TEXACO MULTIGEAR EP 80W-90 SPARTAN EP 320 SUPER MAXOL EP 220 GEAR LUBE or PEN GEAR #320 605 ALMASOL VARIPURPOSE GEAR LUBRICANT GEAR OIL 320 932 INDUSTRIAL GEAR LUBE PHILUBE ALL PURPOSE GEAR OIL 85W-90 GEAR OIL EP220

PENNANT NL S-1000

18. CITIES SERVICE

7. SHELL OIL COMPANY 8. CENTURY LUBRICATING OILS, NC. 9. ATLANTIC RICHFIELD CO.

16. PHILLIPS

CITGO EP COMPOUND 110

SPEC. 100-8 - HYDRAULIC AND GENERAL PURPOSE OIL HEAVY / R & O INHIBITED SUPPLIER

BRAND NAME

SUPPLIER

BRAND NAME

1. AMOCO OIL CO.

AMERICAN INDUSTRIAL OIL NO. 150 HARMONY 150 DTE OIL EX. HEAVY CHEVRON MACHINE OIL AW ISO 150M or CHEVRON MACHINE OIL R&O ISO 150 SUNVIS 961 UNAX RX 700 or TURBINE OIL 700 TURBO 150 CENTRAULIC R & O 150

10. TEXACO LUBRICANTS CO. 11. EXXON 12. PENNZOIL 13. LUBRICATION ENGINEERS

REGAL OIL R & O 150

16. PHILLIPS 17. MINERS OIL

DECTOL R & O 76 SYSTEM 1 150, SYSTEM 5K 150 MAGNUS OILS 700 ISO 150

DURO 600 or S-100

18. CITIES SERVICE

CITGO PACEMAKER 150

2. GULF OIL 3. MOBIL OIL CORP. 4. CHEVRON U.S.A.

5. SUN OIL'COMPANY 6. UNOCAL76 7. SHELL OIL COMPANY 8. CENTURY LUBRICATING OILS, NC. 9. ATLANTIC RICHFIELD CO.

14. CONOCO INC. 15. HYDROTEX

67

TERESSTIC 150 PENNZBELL RO 150 6405 MONOLEC TURBINE OIL

DBT AMERICA

RB2-88 ROOF BOLTER

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SECTION 4 - MECHANICAL FUNCTIONS GENERAL This section of the manual is divided into two parts: Mechanical operation and Mechanical Components. The first deals with the mechanical operation of the machine in general terms.

The second deals more specifically with individual mechanical components,

MECHANICAL OPERATION PRIMARY POWER SOURCE - All of the roof bolter's functions are hydraulically powered (Figure 48) (with the exception of lighting and dust collection).This hydraulic power is supplied by two multiple section (tandem type) hydraulic pumps. Both pumps are of two sections and are driven from the front ends of the electric motors. Dust collection blowers are belt driven and mounted at the back ends of these motors.

PRIMARY POWER SOURCE FIGURE 48

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TRAM AND STEERING SYSTEM - RB2-88 roof bolters are equiped with four wheel drive and automotive type rear wheel steering (Figure 49). The system uses four tram motors (one for each wheel). These motors drive the wheels through planetary reducers at a ratio of about 25:1 or 30:1. The front drive assemblies are rigidly mounted to the machine chassis and include multiple disc parking brakes between the tram motors and reducers. These brakes are applied by spring tension and released by hydraulic pressure. While pressure is present in the tram circuit (during tramming), the brakes are released: while pressure is absent (when parked or when drilling and bolting) the brakes are applied. The rear wheel assemblies are pivoted (for steering) from a bolster, and the bolster is pivoted (to cope with uneven terrain) from the machine chassis. The bolster itself is an axle-like subframe designed to support the rear end of the chassis.

Flow limiters are used in the machine's tram tram circuits. One set of these limiters reduces wheel spin while allowing some differential action at each axle. The other set regulates flow through the inch tram circuit (providing a consistent slow speed).

Steering of the two rear wheels is controlled by a hydraulic steering cylinder and a tie rod.

Fluid to the ends of the cylinder is metered by the power steering control valve.

TRAM AND STEERING SYSTEM FIGURE 49

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DRILLING ROTATION - Rotational force for drilling (Figure 50) is supplied by the gear type drilling rotation motors. These motors are mounted directly to the drill boxes. Each drill box serves to multiply torque while providing a chuck for driving a drill steel or wrench. The torque available at the chuck is determined by hydraulic pressure to the rotation motor. A system of relief valves allows chuck torque to be varied to suit conditions. Drill chuck speed is determined by rate of hydraulic oil flow; this can be controlled by the operator by means of the rotation flow control valve.

DRILLING ROTATION FIGURE 50

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CRADLE, BOOM, AND SUPPORT ARM ASSEMBLIES - The cradle, boom, and support arm assemblies (Figure 51) are mounted to turntables at the front end of the machine. The booms and support arms incorporate slider and hinge linkages to provide straight line vertical motion for the drill boxes and support boxes or rings. Each cradle, on the other hand, incorporates a simple pivot since straight line motion is not necessary for its function. Individual portions of these assemblies are described on the following pages.

CRADLE, BOOM AND SUPPORT ARM ASSEMBLY FIGURE 51

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BOOM OPERATION - The boom (Figure 52) serves to feed the drill box toward the roof during the drilling and bolting sequence. As shown below, the boom linkage is designed so that the motion of the drill box is along a generally vertical straight line. A hydraulic cylinder provides the feed force to the boom. The load applied by this cylinder is transfered partly to the ground through the foot of the cradle, partly to the machine chassis. The feed force of each boom is regulated by two hydraulic relief valves (one in the dual relief valve, one in the control valve bank). Under normal operation, this arrangement provides two distinct feed forces (one for bolting, one for drilling). However, both settings are variable over a wide range to accomodate unusual conditions.

BOOM OPERATION FIGURE 52

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CRADLE - The cradles (Figure 53) serve to provide support for the machine during the drilling and bolting operations. The boom lift and the support arm lift cylinders are anchored to the foot of each cradle so that drilling thrust is fed partially into the ground, and partially into the machine's chassis. A cradle lift cylinder raises the cradle for tramming.

The general form of the cradles are; all of the locating points for the support arm and the boom(slider tracks and hinge points) are suspended from the subframe.

CRADLE FIGURE 53

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SUPPORT ARM OPERATION - The support arm (Figure 54) is designed to provide temporary roof support during the drilling and bolting sequence (when used as an integral part of an approved roof control plan). Like the boom, the support arm incorporates a slider and hinge linkage for vertical straight line motion of the support ring. The support box, however, is allowed to tilt somewhat forward to conform to an uneven roof. A link chain is provided to prevent the support ring from rotating beyond the effective distance.

A pilot operated check valve in this hydraulic circuit prevents the support arm from retracting when forced down externally, as in a roof fall.

SUPPORT ARM FIGURE 54

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CRADLE, BOOM, AND SUPPORT ARM ASSEMBLY: PINS, BUSHINGS, AND SLIDERS Illustrated below (Figure 55) are typical arrangements for the various pivots and sliders used on the machine. Generally, critical wear points are bushed and provided with grease fittings for ease in lubrication. Where nuts are used to retain hinge pins, they are of the elastic locking (Spot Lok) type.

CAUTION SPOT LOK AND NYLON FASTENERS ARE SUBJECT TO WEAR: THEY LOOSE SOME OF THEIR HOLDING POWER WITH EACH REUSE. HENCE, DO NOT REUSE SPOT LOK FASTENERS IN ANY HIGH STRESS AREAS.

TYPICAL SUPPORT ARM CONNECTING LINK TYPICAL CRADLE, BOOM AND SUPPORT ARM HARDWARE FIGURE 55

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TURNTABLE - The RB2-88 roof bolter is equiped with turntables (Figure 56) which permit horizontal swinging of each cradle and boom assembly. The movement of each cradle and boom assembly is controlled by a hydraulic swing cylinder which is connected between the chassis and an anchor point on the turntable. The turntable is mounted on a vertical king pin with tapered roller bearings. A roller, bushing mounted near the edge of the rotation portion of the turntable, accepts much of the cantilevered load which would otherwise have to be handled by the king pin bearings.

TURNTABLE FIGURE 56

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DUST COLLECTION SYSTEM - RB2-88 roof bolters are equipped with a dual dust collection system (Figure 57) with one leg per drill head. Each dust collection system serves two functions.

It clears the hole of dust while drilling is in progress, which increases cutting speed and efficiency. At the same time, by collecting this dust before it can become airborne the collection system effectively deals with a potential health and safety hazard.

Intake to the dust collection system is through an opening in the drill steel, just below the cutting bit. From there, dust laden air and debris is drawn through the drill box hub and flexible tubing into the dust collector. The dust collector separates the dust out of the air, and the clean air is drawn out of the collector by the system blower. This blower exausts through a muffler, which lowers the operating noise level. The blower is driven by the electric motor and a v-belt. A relief valve at the intake to the blower prevents system vacuum from becoming excessive.

DUST COLLECTION SYSTEM FIGURE 57

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CABLE REEL - The RB2-88 roof bolter is provided with a cable reel (Figure 58) to simplify cable handling. The cable reel is driven by a hydraulic motor, through a gear reduction followed by a chain and sprocket reduction. The tension applied to the cable during windup is set by a relief valve in the hydraulic motor circuit.

CABLE REEL FIGURE 58

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MECHANICAL COMPONENTS REEL DRIVE - The reel drive assembly (Figure 59) provides two stage speed reduction as well as a means for adjusting drive chain tension. A gear set serves for the first stage of speed reduction; the chain drive acts as a further reduction. The reel motor mounting plate is slotted to allow for adjustment of chain tension. Adjusting screws are provided to simplify the adjusting procedure and to help maintain the selected position of the mounting plate. A grease fitting provides a convenient method for lubing the bushing in the spur gear/sprocket.

CABLE REEL DRIVE FIGURE 59

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PUMP DRIVE - The double tandem hydraulic pumps are driven directly from the machines electric motors (Figure 60). The motor has a internal, removable spline insert and the pump has a splined shaft that connects it to the motor.

PUMP DRIVE FIGURE 60

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TRAM REDUCER - RB2-88 roof bolters use four (one at each wheel) planetary gear reducers (Figure 61) in their tram systems. The name “Planetary” derives from the motion of the gears within the reducer case. Just as the planets in our solar system spin about their axes as they revolve around the sun, the cluster (planet) gears in the gearbox spin on their axles as the carrier revolves around the input (sun) gear.

Free wheeling or gear disengagement can be attained by rotating the external hub 90°.

TRAM REDUCER FIGURE 61

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MULTIPLE DISC BRAKE - Tram brakes (Figure 62) are used on RB2-88 roof bolters to ensure that the machine remains stationary while parked and during drilling and bolting operations. The brake units are installed between each hydraulic motor and speed reducer on the front axle of each machine. Braking force is applied by six pairs of compression springs inside the brake housing. Hydraulic pressure is used to release the brake.

MULTIPLE DISC PARKING BRAKE FIGURE 62

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DRILL BOX - The drill box (Figure 63) is a specialized bevel gear reducer. The bevel pinion is supported by two tapered roller bearings. The bevel gear is supported by a tapered roller bearing and is splined to the bevel gear hub which is, in turn, is supported by a tapered roller bearing. A chuck (not shown) is splined to the upper end of the hub and serves to transmit rotational force to the drill steel or wrench. Dust is pulled through the hollow chuck and hub and out of the side of the drill box, near the bottom. A face seal at the lower end of the hub prevents the dust collection vacuum from sucking oil out of the gear case. Another lip seal at the top of the hub prevents the entry of dirt and dust into the case.

STANDARD DRILL BOX FIGURE 63

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DUST SYSTEM VACUUM BLOWER - Each dust system blower (Figure 65) employs two double-lobe impellers mounted on parallel shafts and rotating in opposite directions within an impeller case closed at the ends by headplates. As the impellers rotate, air is drawn into one side of the impeller case and forced out the opposite side.

Effective sealing of the blower inlet area from the discharge area is accomplished by use of very small operating clearances. Resulting absence of moving contacts eliminates the need for internal lubrication. Clearances between the impellers during rotation are maintained by a pair of accurately machined timing gears, mounted on the two shafts extended outside the air chamber.

In position 1 (Figure 65), a volume of air (A) is being delivered into the outlet port. At the same time, space (B) between the righthand impeller and impeller case is filling with an equal volume. This space is about to be sealed off by the clockwise rotation of this impeller, for the delivery to the outlet port.

In position 2 (Figure 64), volume (A) continues to discharge into the outlet port, while volume (B) is being moved in the direction of the outlet port. The space between the impeller and the impeller case is beginning to fill.

In position 3 (Figure 64), volume (B) is discharging into the outlet port, and the cycle is ready to begin again.

BLOWER OPERATION FIGURE 64

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BLOWER EXPLODED VIEW FIGURE 65

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DUST COLLECTORS - The RB2-88 roof bolter is equiped with a three stage dust collection system (Figures 66 and 67) contained in a single housing. Dust enters the collector through a hose on the side or back and is carried into the first stage cyclone. This cyclone removes over 95 percent of all incoming dust and water and deposits them in the main dust storage chamber.

TYPICAL DUST BOX FIGURE 66 Fine dust exits the top of the first stage cyclone through an air expansion chamber where it goes to the second stage separator. The second stage separator tubes are reverse-flow mini cyclones which remove over 84 percent of the fine dust from the air. Thus, less than 1 percent of the total incoming dust passes out the top of the second stage and through a hose to the final filter stage.

The third stage filter is a heavy-duty, pleated paper cartridge type element. Dust collected on this filter is fine (less than 15 microns in size), yet is removed with an efficiency of over 99.9 percent. Clean air passes through the final filter to the exit manifold and outlet hose.

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DUST COLLECTION STAGES FIGURE 67

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SECTION 5 - HYDRAULIC FUNCTIONS

GENERAL HYDRAULIC SYMBOLS FIGURE 68 89

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PURPOSE This portion of the RB2-88 instruction Guide is divided into three parts. The first provides an introduction to general hydraulic principles and schematic reading; the second deals with the functioning of the roof bolters hydraulic circuits; and the third details the operating principles of the individual components which make up these circuits.

GENERAL A schematic diagram is a “roadmap” to show the fluid flow between and through components in a circuit and between different circuits on a machine. A schematic does not represent the actual physical installation of the components. Pipe fittings, for example, are omitted from schematics. Also, there is not necessarily any connection between the location of symbols on the schematic and the components on the machine.

Hydraulic components are represented on a schematic diagram by symbols. Figure 68 explains the meanings of various hydraulic symbols you will encounter while tracing the circuits of the RB2-88 roof bolter covered in this guide.

The component symbols are linked together on a schematic diagram by lines that represent the hydraulic hoses and pipes on the machine. Lines can be shown crossing in three different ways .

The schematic symbol for a valve shows the position of the valve within the circuit as well as its function. When looking at a valve's schematic symbol, first look at the valve's “envelope” (the square or rectangle that encloses the valve's flow symbols). If the valve has two segments: the valve has two positions;

a three position valve is shown by a three segment envelope:

When interpreting the valve symbol, the envelope is imagined to move from one position to another relative to the lines leading into and out of the valve symbol:

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Often, the lines leading into and out of the valve symbol will be labeled :

In this case, T stands for tank, P for pump (or pressure), and C1 and C2 are the cylinder (or work or load) ports.

The lines and arrows within the valve symbol show where the flow goes when when the valve is in each of its positions.

The symbol shows that when the valve is centered, both cylinder ports are connected to tank and the pressure port is blocked. Additional flow symbols are added to show the flow conditions when the valve is shifted in either direction:

In this case, when the valve is shifted to the right, the pump output is connected to port C2, and C1 is connected to tank. When the valve is shifted to the left, the pump output goes to C1, and C2 is connected to tank. If ports C1 and C2 were connected to a hydraulic motor, the motor would freewheel when the valve is centered, would be powered in one direction when the valve is shifted to the right, and would be powered in the opposite direction when the valve is shifted to the left.

Additional symbols are added to the basic valve symbol to show how the valve spool (the moving part of the valve which, working with the valve body, directs flow through the valve) is moved, how its position is maintained, etc. For example, this valve:

is spring centered, as shown by the spring symbols at each end of the envelope. This two position valve is sprinq offset: it is held in its closed position by spring force.

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Another alternative for maintaining a spool position is a detent assembly. Here is the symbol for a three position valve with detents for all three positions:

There is a notch in the detent symbol for each detented position. The detent in use for the position in which the valve is drawn is marked with a short vertical line.

Symbols for springs and detents can be used in combination. For example, this valve symbol:

indicates that the valve is detented in its centered position and when shifted to the left. The spring returns the valve spool to center after the spool has been shifted to the right and the control is released.

Methods for actuating the valve are also shown by symbols added to the basic valve symbol.

A valve actuated manually by a lever would be shown like this:

If the valve is actuated by a knob attached directly to an extension of the spool, it could be shown like this:

Valves can also be actuated by pilot pressure. A pilot actuator usually takes the form of a miniature hydraulic cylinder, the piston of which is attached to the valve spool. Schematically, a pilot operated valve can be shown like this:

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The two pilot actuators shown indicate that the valve can be shifted in either direction by pilot pressure. The valve itself would probably have a single, double-acting actuator. (Remember that a schematic symbol is intended to show the function of a component, not its actual physical makeup). Another way of showing the same function is this:

Pilot pressure generally arrives at the pilot actuated valve by way of another valve (often called a pilot valve) and is shown schematically as a dotted line. Sometimes, this line alone is used to indicate pilot actuation of a valve, as here:

Valves can also be actuated by solenoids, as shown here:

Yet another alternative for valve actuation is servo control:

A servo circuit provides automatic control by the combination of an input signal (an operator moving a valve handle, for example) and feedback from the system's output. The feedback could take the form of an electric, hydraulic, or mechanical signal which could indicate a speed, a force, or a position of a element of the system.

Often, a servo valve can make a smooth transition from one position to another, rather than acting like a snap action switch. This feature can be indicated by using dashed lines between the envelope segments:

Sometimes, this same feature is indicated by lines parallel to the valve symbol envelope:

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Due to space reasons, the servo actuator symbol is often shown on only one end of the valve envelope, even though the actuator can shift the valve spool in either direction. For example, this symbol:

indicates that the valve can be controlled either manually or by the servo actuator. It is assumed that the actuator can move the valve spool in either direction.

Pressure control valves (relief valves, pressure reducing valves, sequence valves, etc.) are shown in a somewhat different way than are the direction control valves we've been discussing.

These valves are generally shown as a single section envelope with a flow indicating arrow which is imagined to move as the valve operates:

The valve will usually be shown offset by a spring:

If the spring force is adjustable, an arrow is drawn at an angle through the spring symbol:

The pressure which shifts the valve spool is depicted as a dashed line:

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A typical pressure relief valve can be imagined to work this way:

A pressure reducing valve operates this way:

A sequence valve, which operates much like a relief valve, works like this:

Schematic symbols like the ones we've discussed, and others, are used in the following introduction to hydraulic principles. Later in the section, a schematic symbol is placed near the illustration of each component to associate the symbol with the component.

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BASIC ELEMENTS OF HYDRAULICS “Power hydraulics” is the study of a confined, pressurized fluid. On DBT America roof bolters, the fluid is hydraulic mineral oil or in some cases, a fire-resistant fluid. The roof bolters use hydraulic fluid to transmit power from a pump to a motor or a hydraulic cylinder (jack).

A basic hydraulic circuit (Figure 69) consists of a tank (reservoir) to store the fluid, a pump to move the fluid, and a motor or cylinder to perform work. The pump draws fluid out of the tank and moves it to the motor. The fluid passes through the motor and causes it to rotate. The fluid then returns to the tank to be used again. This basic circuit can be modified in many ways. It is important to remember that every hydraulic circuit is a variation on this basic circuit.

FIGURE 69 The circuit could be modified to run two hydraulic motors instead of just one (Figure 70). In this example, the pump continues to deliver the same amount of hydraulic fluid into the circuit.

However, the fluid is now divided into two equal flows, with one flow going to each motor. Each motor will now turn only half as fast as it did in the first example, because the speed with which any hydraulic device operates is related to the rate of oil flow in the circuit. REMEMBER: SPEED DEPENDS ON FLOW RATE, NOT ON PRESSURE. The flow rate is measured in gpm "gallons per minute.” If the pump in the example delivers 50 gpm, each motor has 25 gallons of fluid flowing through it each minute.

FIGURE 70

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Another way to modify a circuit is to change the pressure in it (Figure 71). It is important to note that a pump does not generate pressure; a pump merely moves fluid from one place to another. Pressure develops when the moving oil runs up against an obstruction. In Figure 69, for instance, there is no pressure to speak of being developed: the pump merely moves the fluid from one side of the tank to the other side.

FIGURE 71 In Figure 72, however, the situation changes. Instead of having a uniform flow through the circuit, the oil must now squeeze through a restriction. The restriction causes pressure to develop in the line between the pump and the restriction. The hydraulic principle demonstrated in Figure 72 can be seen in a common experience most of us have had with a water hose. If we have "low pressure” we can manage to shoot the stream of water further by using our thumb to partially block the end of the hose. The thumb acts like the restriction in Figure 72. Before we restrict the water flow, there is little pressure because the water does not encounter any obstructions. When our thumb closes off part of the hose outlet, the water cannot escape as easily as before. As a result, pressure develops in the hose. The water coming out of the hose then has more pressure behind it and the water spray goes further.

FIGURE 72

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In Figure 72, there is nothing in the circuit to hinder the flow once it gets past the restriction, so there is virtually no pressure between the restriction and the tank. Thus, the oil loses its pressure as it passes through the restriction, but pressure is maintained between the pump and the restriction. Because of this difference in pressure, it is said that a "pressure drop” occurs across the restriction. All valves, fittings, and actuators cause a pressure drop in a flowing circuit.

As shown in Figure 72, the pressure can vary in different parts of the same circuit. The "operating pressure” is the pressure developed between a pump and a hydraulic device such as a motor, cylinder or even a restriction, as in our example. (A stalled motor or a jack which has "bottomed out” is a complete restriction and the oil pressure will rise in the circuit until it reaches the relief valve setting). When we refer to an 800 psi circuit, we mean that the circuit's maximum operating pressure is 800 psi.

Figure 73 shows how a relief valve can be used to limit the operating pressure in a simple circuit. As in Figure 72, the restriction causes pressure to rise in the line between the pump and the restriction. If the pressure rises to the relief valve setting, the relief valve will open, diverting flow to tank. By providing an alternate path for flow, the relief valve reduces the effect of the restriction and limits the operating pressure. Relief valves can be used to limit motor torque or cylinder thrust, or to protect components from excessive pressure.

FIGURE 73 In each simplified example we’ve discussed, the circuit is in operation whenever the pump is running. Of course, this is not a very practical arrangement. (Imagine trying to use a roof bolter that began to tram, drill, and retrieve its cable as soon as the pump motor was turned on!) Control valves are the solution to this problem. Figures 74, 75, and 76 demonstrate some ways in which control valves can be used to direct flow.

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ON - OFF CONTROL FIGURE 74

FWD. - OFF - REV. CONTROL FIGURE 75

FWD. - OFF - REV. WITHFLOW THROUGH CENTER FIGURE 76

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Let's see if we can throw some components together and come up with a useful circuit.

Suppose we want to devise a tram circuit for a roof bolter. First we'll have to decide on pump size and operating pressure, based on machine weight, desired speed range, maximum expected grade, etc. We'll assume we've done the calculations necessary and found that we need a 35 gpm pump operating at a maximum pressure of 1000 psi (Figure 77).

FIGURE 77 We'll need a control valve to provide forward and reverse tram. Since we don't want to be using power unnecessarily when we're not tramming, we'll use a valve with flow through center.

We'll power two tram motors for two wheel drive (Figure 78). And there we have it (a simple tram circuit).

FIGURE 78 Under ideal conditions, the circuit would work just fine. But conditions in a mine are far from ideal. Traction can be a problem since the bottom is often slippery and uneven. What would happen to our roof bolter if one of our two drive wheels was lightly loaded on a slippery surface?

It would spin, of course. Unfortunately, hydraulic fluid is lazy stuff; it always takes the easy way out. With one wheel spinning, all 35 gpm will go back to tank through that tram motor. The motor at the wheel with good traction would receive little, if any, fluid, and the roof bolter would be stopped dead in its tracks.

Here's the same basic circuit (Figure 79), modified to limit wheel spin:

FIGURE 79

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The flow limiters limit the maximum flow to each motor to 20 gpm. Since the motors get only 17.5 gpm each when running at full speed on a good surface, the flow limiters do not come into play during normal operation. However, should one wheel begin to spin, the flow to that wheel's motor is limited to 20 gpm. Of the 35 gpm coming from the pump, 15 gpm would be forced to flow through the other tram motor. The effect is to provide power to both wheels even under adverse conditions.

The tram circuit we've just discussed is similar to (but much simpler than) than that used on the RB2-88 roof bolters. The actual RB2-88 tram circuit, as well as the machine's other circuits, are discussed on the following pages. When examining a hydraulic circuit, look for the FLOW and the PRESSURE. Ask yourself the questions, "Where does the fluid go?” and “How is the pressure created?” On the pages that follow, you will see different ways of varying both flow and pressure in a circuit, but remember that all hydraulic circuits are only variations on the most basic circuit discussed earlier.

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HYDRAULIC CIRCUITS Figure 80 shows a typical hydraulic schematic of the RB2-88 roof bolter. You will find it helpful to refer back to the schematic diagram when reading about a particular circuit or component. This will enable you to see how the individual circuits are interrelated.

Following the complete schematic are descriptions of the machine's individual circuits. These descriptions are accompanied by schematic illustrations.

TRAM CIRCUITS The RB2-88 roof bolters incorporate a number of useful features into their tram circuits: • Limited slip circuitry - by reducing wheel spin, full effect of four wheel drive is achieved; • Motion control - provides dynamic hydraulic braking and ensures that the bolter will not “run away” on downhills; • Inch tram at right hand front controls - provides a consistent slow speed for accurate positioning of bolter; • Automatic parking brakes - ensure that the machine remains stationary while parked and during drilling and bolting operations.

Motion control and automatic parking brakes operate on the front wheels only; the limited slip circuitry affects all four wheels during normal tramming; likewise, the inch tram circuit supplies fluid to all four wheel motors.

The front and rear normal speed tram circuits are hydraulically independent (each circuit has its own pump and control valve). (The only hydraulic link between the two is through the inch tram circuit.) The control valves are, however, mechanically linked so that the two circuits operate together. We'll discuss the tram circuits in order of complexity: rear tram circuit first, front tram circuit next, and finally the inch tram circuit (which operates on both the front and rear wheels).

WARNING DO NOT MOVE ANY HYDRAULIC CONTROL LEVER UNLESS YOU ARE CERTAIN THAT NO ONE COULD BE HURT BY THE MACHINE'S MOVEMENT. DO NOT DISCONNECT A HYDRAULIC CIRCUIT FROM A CYLINDER WHILE THERE IS A LOAD ON THE CYLINDER.

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HYDRAULIC SCHEMATIC FIGURE 80 103

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REAR TRAM CIRCUIT - The rear tram circuit (Figure 81) is supplied with fluid by the 40 gpm section of the double tandem pump. From the pump, fluid flows to the rear tram control valve, which can either shut off flow to the tram motors or direct flow through the motors in the forward or reverse direction. An inlet relief valve in the rear tram control valve sets the maximum circuit pressure at 1800 psi. The rear tram control valve is of the flow-through center type so that no pressure is developed between the pump and the valve when the valve is centered. This valve design also allows flow from the 40 gpm section of the double tandem pump to be used elsewhere on the machine.

Port relief valves are used at each outlet port of the control valve and serve two functions.

First, they protect the circuit downstream of the valve from excessive pressures when the valve is centered. (Such pressures could develop if the tram motor was rotated by an external force such as machine inertia, or from the hydraulic shock that would occur if the control valve were quickly centered). Second, these port reliefs serve as back-ups for the main relief while the control valve is in either of its open positions.

From the control valve, fluid is directed to the tram motors through 24 gpm flow limiters.

These flow limiters are used for limited slip tramming action and will prevent all 40 gpm of pump delivery from going through a single tram motor if the related wheel is spinning. At least 16 (40 24 = 16) gpm is forced to go through the motor at the wheel with better traction. This 16 gpm flow is sufficent to propel the bolter at about 2/3 normal speed.

The 24 gpm flow value chosen for the tram flow limiters gives a good compromise between straight line traction (limited slip) and turning responce (differential action). They will allow the outside wheel to turn about twice (actually 24/11) as fast as the inside wheel when the bolter is negotiating a bend, yet will also provide effective limited slip action.

After flowing through the tram motors, fluid returns to tank through the tram control valve.

REAR TRAM CIRCUIT FIGURE 81

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FRONT TRAM CIRCUIT - Although motion control and automatic parking brakes add some complexity to the front circuit (Figure 82) that is not present in the rear circuit, many of the components used in the two circuits are similar.

The 40 gpm section of the double tandem pump supplies fluid to the front tram control valve.

As in the rear circuit, the control valve is of flow through type, includes an 1800 psi inlet relief valve, and uses two port reliefs.

From the control valve, fluid is directed to the automatic parking brakes and to the motion control valve. The motion control valve will not permit fluid to return to tank from the tram motors until pressure in the line from the control valve reaches 300 psi. This function of the motion control valve serves two purposes. First it establishes a back pressure in the circuit that is sufficient to completely release the automatic parking brakes before any movement of the tram motors can take place. This reduces wear on the parking brakes. (These brakes are released by hydraulic pressure and applied automatically by spring tension). Second, the motion control valve ensures that the movement of the bolter is at all times under the control of the operator. In particular, any tendency for the machine to “run away” on downhills is eliminated. If the speed of the bolter exceeds the speed that the operator is calling for (according to his positioning of the tram control valve pedal) the pressure in the line supplying the motors will drop. This occurs because the motor's demand for fluid begins to exceed the supply from the control valve. When the pressure drops below 300 psi, the motion control valve restricts the flow out of the motor and prevents the machine from going any faster.

The motion control valve also serves to protect the "downstream” circuit from excessive pressures by acting as a 2000 psi relief valve. Normally, this relief would rarely come into play since the main circuit relief in the tram control valve is set at 1800 psi. However, this relief valve can act as a back-up for the main relief, and will also protect the downstream circuit from damage while the control valve is centered. (It serves the same purpose as a port relief valve).

Notice that the lines from the tram control valve to the motion control valve tee to a shuttle valve which controls flow into the automatic parking brakes. This shuttle valve permits flow from either side of the control valve to the brakes but will block flow from one port of the control valve to the other. Both sides of the tram control valve must be piped to the brakes so that the brakes will release during both forward and reverse tram. If a simple tee were used instead of the shuttle valve, all of the flow from the control valve would bypass the tram motors, and the machine would go nowhere.

A needle valve is used to drain the brake units to tank after the control valve is centered. The small amount of fluid that flows through the needle valve (if properly adjusted) during normal tramming has an insignificant effect on tram speed.

The operation of the flow limiters in the front tram circuit is as described for those in the rear circuit.

FRONT TRAM CIRCUIT FIGURE 82

105

DBT AMERICA

RB2-88 ROOF BOLTER

INCH TRAM CIRCUIT - The inch tram circuit (Figure 83) receives its supply of fluid from a 40 gpm section of the double tandem pump. The inch tram control valve is located in the right hand cradle valve bank. Lines tee from each working port of the control valve (one line to the rear circuit through a 6 gpm flow limiter, the other to the motion control valve through another 6 gpm flow limiter). Because of these limiters, the front and rear circuits receive about 1/6 of the flow that they would during normal tramming. The motion control valve and automatic brakes operate exactly as they do during normal tramming. The limited slip circuitry, on the other hand, is inoperative during inch tramming since the flow rate during inch tramming never reaches the 24 gpm at which the anti-spin flow limiters have their effect. A mid-inlet relief valve in the right hand cradle control valve bank sets maximum pressure in the inch tram circuit at 1200 psi.

INCH TRAM CIRCUIT FIGURE 83

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RB2-88 ROOF BOLTER

DBT AMERICA

STEERING CIRCUIT - RB2-88 roof bolters are equipped with hydraulic power steering. This steering system provides accurate steering control with low effort. The steering circuit (Figure 84) receives its fluid from a 15 gpm section of the double tandem pump. A 1250 psi relief valve, located in the supply line from the pump, establishes maximum circuit pressure. Between this relief valve and the steering control valve is a priority valve, set at 650 psi. The priority valve will not allow fluid into the steering control valve unless the pressure in the supply line from the pump is at least 650 psi. This valve maintains pressure in the support arm circuit, which is supplied by the same pump section. In operation, the steering is much like that on an automobile (except that the roof bolters's wheels do not straighten themselves out after making a turn). The operator must turn the steering control wheel to resume straight line travel, rather than simply letting it slip through his hand as he might do in a automobile. If for some reason the supply to the steering control valve should fail, the steering will still operate (but with much greater effort). This is possible because a check valve in the steering control valve allows the metering section to act as a manually powered pump, drawing its fluid from tank and delivering it to the steering cylinder.

STEERING CIRCUIT FIGURE 84

107

DBT AMERICA

RB2-88 ROOF BOLTER

ROTATION (DRILLING CONTROL) VALVE BANK CIRCUIT - The machine uses two identical rotation valve banks (one per side). Included in these valve banks are controls for feed, boost, and rotation. The schematic for one of these valve banks is shown below (Figure 85). The boom feed valve is supplied by a 15 gpm section of the double tandem pump. A 40 gpm section of the double tandem pump supplies the rotation valve with fluid. This 40 gpm supply arrives at the rotation valve by way of the front or rear tram valve (front tram valve - R.H., rear tram valve L.H.). By adding this 40 gpm flow to the normal 15 gpm flow for the feed valve, the boost valve can roughly triple the speed of the feed function. Maximum pressure in the feed circuit is established by a mid-inlet relief valve normally set at 900 psi. (This setting can be varied to adjust feed force.) Maximum pressure in the rotation circuit is limited by an inlet relief valve set 1800 psi.

(Changing this setting will change rotation torque.) The individual circuits controlled by a rotation valve bank are described on the following pages.

ROTATION (DRILLING CONTROL) VALVE BANK CIRCUIT FIGURE 85

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ROTATION - The rotation circuit (Figure 86) supplies the drill rotation motor with fluid under controlled pressure and flow. The circuit consists of a control valve, an inlet relief valve, a portion of the dual relief valve, a flow control valve, the rotation motor, and, of course, interconnecting piping. The control valve is a four way directional control valve.

When the dual relief valve is in the "OFF” position, torque at the drill head is limited by the inlet relief valve (variable to suit mine conditions). When the dual relief valve is in the "ON” position, torque is limited to a lower value (also variable to suit conditions).

The flow control valve is used to limit the rotation speed of the drill head. Of the 40 gpm flow to the rotation control valve a portion can be diverted back to tank through this flow control valve (the more the flow through the flow control valve, the slower the drill speed).

ROTATION CIRCUIT FIGURE 86

109

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RB2-88 ROOF BOLTER

FAST FEED CIRCUIT - The fast feed circuit (Figure 87) serves to increase the operating speed of the machine's rotation valve bank functions. The circuit operates by adding together the 40 gpm and 15 gpm supplies for the rotation valve bank. By providing a 50 gpm flow, the boost circuit can roughly triple the speed of the functions normally supplied with 15 gpm , and can increase rotation speed by about 40%.

FAST FEED CIRCUIT FIGURE 87

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FEED (BOOM LIFT) CIRCUIT - The feed circuit (Figure 88) supplies the boom lift cylinder with fluid at controlled pressure and flow. The circuit includes a control valve, half of the dual relief valve, a flow control valve, the feed cylinder with pilot check valve, and related piping. The control valve is a four-way, three position directional control valve, with flow through center. A mid-inlet relief valve limits boom thrust during drilling. This valve is factory set at 1800 psi, although it should be reset, if necessary, to suit specific mining conditions.

The half of the dual relief valve that is not used for torque control is used for boom thrust control during bolt torquing. Generally, the dual relief is set to provide just enough force that firm contact between the wrench and bolt head is maintained during bolt torquing. (For resin bolting, the dual relief valve can be used to limit thrust during drilling to protect the smaller diameter drill rod).

The flow control valve limits feed speed (the speed of the upward motion of the boom). As the flow control is opened up, fluid is bled off to tank, slowing boom lift.

FEED (BOOM LIFT) CIRCUIT FIGURE 88

111

DBT AMERICA

RB2-88 ROOF BOLTER

CRADLE VALVE BANK CIRCUITS - Included in each cradle valve bank (Figure 89) are valves to control support arm lift, cradle swing, and cradle lift. The right hand cradle valve bank also includes the inch tram control valve (the operation of which has been described under the heading "INCH TRAM CIRCUIT”).

The support arm valves on both sides of the machine are supplied with fluid from the same pump section (a 40 gpm section of the double tandem pump). Right hand and left hand cradle lift and swing controls receive fluid from 40 gpm sections of the double pumps respectively. A midinlet relief valve establishes maximum pressure for the cradle lift and swing functions; a sequence valve located remotely from the valve bank limits pressure in the support arm circuit.

Parallel supplies to the cradle lift and swing valves allow both functions to operate at the same time, if desired. Flow through from these valves is used to supply the feed valve in the rotation valve banks. Actuating a cradle valve will cut off supply to the feed valve, since they are supplied in series with the cradle valves.

The individual cradle valve bank circuits are described on the following pages.

CRADLE VALVE BANK CIRCUIT FIGURE 89

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SUPPORT ARM CIRCUIT - The support arm circuit (Figure 90) provides a means for controlling the elevation (lowering and raising) of the support arm. The circuit includes a support arm control valve, a support arm cylinder assembly with pilot operated check valve(s), and related piping.

The supply for the circuit comes from a 15 gpm section of the double tandem pump. A circuit pressure of 700 psi is established by the sequence valve. Since the supply line to the support arm control valve deadends in the valve, this 700 psi pressure is maintained even when the control valve is centered. The support arm control valve is self-centering and will return to a neutral position automatically. Even if the cradle settles into the bottom while drilling, the support arm will rise to compensate, provided the control valve is left in the spring return “UP” position.

SUPPORT ARM CIRCUIT FIGURE 90

113

DBT AMERICA

RB2-88 ROOF BOLTER

CRADLE SWING CIRCUIT - The cradle swing circuit (Figure 91) controls the horizontal (side to side) movement of the cradle assembly. included in the circuit are the cradle swing valve, the swing cylinder, an orifice fitting, the mid-inlet relief valve, and related piping. Supply of fluid to the control valve is at 15 gpm, and the mid-inlet relief valve establishes maximum circuit pressure at 900 psi.

Depending on handle position, the cradle swing control valve directs fluid to the rod end or blind end of the double acting swing cylinder, or blocks flow to and from both ends. An orifice fitting in the line into the blind end of the cylinder regulates swing speed.

These cylinders have integral relief valves as well as pilot operated check valves. The relief valves will protect the cylinders from excessive pressures that could be caused either by thermal expansion of the oil contained within a cylinder or by an external force acting on the cylinder (bumping a cradle into the rib while tramming, for example). As a result, the relief valves significantly increase the reliability of the swing cylinders by reducing the possibility of rod breakage. In order for these relief valves to function, it is necessary to use a control valve which has both cylinder ports open to tank when the spool is centered.

The integral check valves provide an important safety feature. These valves will prevent unintended horizontal (sideways) movement of the cradle even if one of the hydraulic hoses leading to a swing cylinder should leak or fail.

CRADLE SWING CIRCUIT FIGURE 91

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CRADLE LIFT CIRCUIT - The cradle lift circuit (Figure 92) controls the elevation (raising and lowering) of the cradle assembly. A single acting cylinder is used to raise the cradle: fluid is pumped into the blind end of the cylinder to lift the cradle and gravity takes care of lowering it.

The control valve can direct flow into the cylinder, block flow into or out of the cylinder, or allow fluid to escape to tank during cradle lowering. The rate at which fliud can escape from the cylinder is limited by a flow control in the line between the valve and the cylinder. This flow control prevents the cradle from lowering at an unsafe rate.

A port relief is used to protect the circuit from excessive pressures while the control valve is closed. This relief would dump if the cradle began to sink into a soft bottom during drilling, for example. While the cradle lift control valve is in the "UP” position, the mid-inlet relief valve prevents excessive pressures from developing.

CRADLE LIFT CIRCUIT FIGURE 92

115

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RB2-88 ROOF BOLTER

CABLE REEL CIRCUIT - The cable reel circuit (Figure 93) provides a method for controlling the rotation of the cable reel. The circuit consists of a control valve, a relief valve, the reel motor, and related piping. The control valve is a four-way, detented, three position directional control valve.

A handle stop locks out one of the three positions to ensure that the motor will only be powered in the direction that retrieves the cable.

Centering the control valve joins the lines from both sides of the motor, permitting the motor to rotate freely. This allows cable to be payed out.

Shifting the valve to the "ON” position causes fluid to flow through the reel motor in the direction which retrieves the cable. The circuit relief valve limits reel torque, and therefore cable tension, during retrieval of the cable. This relief valve should be set so that a person can pull cable off the reel with the control valve in the retrieve position. This setting should provide sufficient tension for retrieval of the cable without posing a safety hazard from excessive tension.

CABLE REEL CIRCUIT FIGURE 93

116

RB2-88 ROOF BOLTER

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HYDRAULIC COMPONENTS DOUBLE TANDEM PUMP - The double tandem pump (Figure 94) consists of two gear type hydraulic pumps on a common shaft. One pump section displaces 15 gpm and the other displaces 40 gpm.

A gear pump develops flow by carrying fluid between the teeth of two meshed gears. One gear is driven by the drive shaft and turns the other. The pumping chambers formed between the gear teeth are enclosed by the pump housing and thrust plates.

A partial vacuum is created at the inlet as the gear teeth unmesh. Fluid flows in to fill the space and is carried around the outside of the gears. As the teeth mesh again at the outlet the fluid is forced out.

GEAR TYPE HYDRAULIC PUMP FIGURE 94

117

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RB2-88 ROOF BOLTER

GEAR TYPE HYDRAULIC MOTORS - The hydraulic motors used on RB2-88 roof bolters (Figure 95) for reel drive and rotation are gear type and are all of similar construction.

A gear motor develops torque through pressure on the surfaces of gear teeth. The two gears mesh and rotate together, with only one gear coupled to the drive shaft. The direction of any gear type motor can be reversed by simply reversing the direction of oil flow.

GEAR TYPE HYDRAULIC MOTOR FIGURE 95

118

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TRAM MOTORS - The main working element of the RB2-88 tram motor (Figure 96) is the Geroler displacement mechanism. This mechanism consists of a six lobed rotor, moving in a housing containing seven rollers. The spaces between the rotor, rollers, and housing form seven working chambers. As the rotor moves, the volume of these chambers changes. A disc valve, driven by the rotor, opens the port into each chamber to input when the volume of that chamber is at its minimum. Fluid entering the chamber drives the rotor around until maximum chamber volume is reached. At that point, the chamber's port is opened to tank (again, under control of the disc valve) and the chamber exausts until minimum volume is reached. All seven chambers in the motor are working all the time - each one at a slightly different point in its cycle from the next one. (For simplicity, the illustration below shows the operation of a single chamber). As a result, this type of motor can displace a large volume for its physical size, and produces high torque at low speed.

TRAM MOTOR OPERATION FIGURE 96

119

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RB2-88 ROOF BOLTER

TRAM MOTOR FIGURE 97

120

RB2-88 ROOF BOLTER

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STEERING VALVE - The steering valve (Figure 98) is used to meter fluid, in controlled quantities, to the steering cylinder. A gerotor displacement element, mechanically coupled to the steering column, does the metering. The coupling of the steering column with the metering section takes place through a spring centered spool-and-sleeve valve. Turning the steering wheel opens this valve and allows fluid from one of the machine's pump sections to flow into the geroter. As the geroter is turned (at this point, the vast majority of effort is is being supplied by pump pressure) a metered quantity of fluid is delivered to the steering cylinder. All of the work of steering is accomplished by the machine's hydraulic pump.

If, for some reason, the pump supplying the steering valve should fail, manual control of steering is still possible. A check valve in the steering valve housing allows the geroter to act as a pump, drawing its fluid from tank. Turning the wheel will pump this fluid to the steering cylinder at the same volume as during normal operation. The effort involved will, of course, be much greater than normal.

STEERING VALVE FIGURE 98

121

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RB2-88 ROOF BOLTER

CONTROL VALVES - Control valves (Figure 99) are used on the RB2-88 roof bolter both singly (as in the tram valves), and in banks of more than one valve (as in the rotation valve bank). All of the control valves are of similar design. Each unit control valve section has threaded working ports, but otherwise has no provision for connection of hydraulic fittings. Therefore, regardless of whether a unit control valve is used alone or in a group, an inlet section and outlet section are required. The inlet section provides a connection point for the line from the pump, and often incorporates a relief valve as well. The outlet section provides a tank port and flow through port.

Most of the valves used on RB2-88 roof bolters are of the flow through center type. This type of valving has two principle benefits. First, it allows the output of one pump section to be used for multiple functions. Second, the pump output can flow to tank with very little restriction when no control valves are actuated. This last feature means that negligible horsepower is used - and little heat is generated - when all control valves are centered.

CONTROL VALVE FIGURE 99

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UNIT CONTROL VALVE OPERATION - (See Figures 100 and 101) A typical valve bank has two flow passages running horizontally through the inlet section and all working sections. Flow is through the upper passage in the entire bank from inlet through outlet if all spools in the bank are in the neutral position.

UNIT CONTROL VALVE OPERATION FIGURE 100 If any spool of a unit control valve is moved to an operating position, through-flow in the upper passage is blocked at this point and flow is diverted into the parallel passage. The entire parallel passage is pressurized by this action, since it is dead-ended in the outlet section. Pressurized fluid then forces open the check valve in the base of the actuated unit control valve and flows out the open working port. Return flow into the unit control valve is diverted to the tank return passage.

UNIT CONTROL VALVE OPERATION FIGURE 101

123

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RB2-88 ROOF BOLTER

MOTION CONTROL VALVE - The motion control valve (Figure 102) will not permit fluid to return to tank from the tram motors until pressure in the line from the tram control valve reaches 300 psi.

This function of the motion control valve serves two purposes. First, it establishes a back pressure in the circuit that is sufficient to completely release the automatic parking brakes before any movement of the tram motors can take place. This reduces wear on the parking brakes.

Second, it provides hydraulic braking by blocking flow out of the tram motors (which prevents the machine from moving) unless there is pressure in the line from the control valve.

The motion control valve can also act as a pair of 2000 psi relief valves. These act much like port reliefs, protecting the circuit downstream of the tram control valve when the tram control valve is centered. For example, if the tram valve is rapidly closed while the roof bolter is underway, the momentum of the machine can cause a severe pressure buildup in the return line from the tram motors. Under this condition, the motion control valve will act as a "brake valve”, maintaining enough pressure to quickly slow the machine while preventing the buildup of excessive pressures.

MOTION CONTROL VALVE FIGURE 102

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RB2-88 ROOF BOLTER

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DUAL RELIEF VALVE - The dual relief valve (Figure 103) consists of a manually operated rotary valve, two pressure relief valves, and two pilot operated straightway valves in a single housing.

The pressure setting on the two relief valves can be varied to suit mine conditions. One limits boom thrust, and the other limits drill box torque.

DUAL RELIEF FIGURE 103

125

DBT AMERICA

RB2-88 ROOF BOLTER

PILOT RELIEF VALVE - A pilot relief valve (Figure 104) is used for pressure control in the circuits supplied by the 15 gpm section of the double tandem pump.

A pilot relief valve operates in two stages. The pilot stage in the upper valve body contains the pressure limiting valve - a poppet held against its seat by an adjustable spring. The port connections are made to the lower body, and diversion of the major volume of oil is accomplished by a “balanced piston” in the lower body.

Pressure at the inlet port acting under the piston is also sensed on its top by means of the orifice connecting the two sides. At any pressure less than the valve setting, the piston is held on its seat by the light spring. When the valve setting is reached, the poppet is forced off its seat, lowering pressure in the upper chamber. The restricted flow through the orifice into the upper chamber maintains the pressure in the lower chamber. This difference in pressure above and below the piston causes it to raise off its seat, permitting flow to tank.

PILOT RELIEF VALVE FIGURE 104

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RB2-88 ROOF BOLTER

DBT AMERICA

CARTRIDGE RELIEF VALVES - Cartridge relief valves (Figure 105) are used at various locations throughout the roof bolter. All main inlet relief valves used in valve banks are of this type; the relief valve for the cable reel drive motor circuit on most machines also utilizes a cartridge type valve.

These cartridge relief valves are of the direct acting type. Normally, sealing is accomplished between the fixed poppet and the floating seat, under spring tension. When pressure under the floating seat exceeds the valve setting, the seat is forced off of its poppet, against the tension of the spring. This permits flow to tank. A chamber in the floating seat is enclosed at one end by an o-ring sealed piston, and at the other end by a disc with a small hole in its center. This orifice serves to regulate the flow into and out of the chamber. By this means the motion of the floating seat is snubbed, giving smoother valve action and less seat wear.

CARTRIDGE RELIEF VALVE FIGURE 105

127

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RB2-88 ROOF BOLTER

PORT RELIEF VALVES - Port relief valves (Figure 106) are used on some of the roof bolter's directional control valves. They can take either of two general forms: crossover reliefs - in which one working port relieves to the other; and tank reliefs - in which a working port relieves directly to the tank port.

The crossover relief valve and the tank relief valve differ only in the location of their ports, and in the manner in which they function when installed in the directional valve body. The check valve is used, in the crossover type, to allow free flow in one direction, and restricted flow in the other - flow into the end port is permitted only if the fluid pressure is above the valve setting. In the tank relief type, the check valve functions only when replenishing of a cylinder is required something that could happen if a cylinder were forced in one direction or the other while the control valve was centered.

These relief valve cartridges are illustrated below (Figure 106). The operation of these valves, as installed in a control valve, is depicted on the following page (Figure 107).

PORT RELIEF VALVES FIGURE 106

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PORT RELIEF VALVES FIGURE 107

129

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RB2-88 ROOF BOLTER

PILOT OPERATED CHECK VALVES - Pilot operated check valves (Figure 108) are used in the boom lift and support arm circuits. This type of valve allows free flow in one direction and blocks flow in the other direction as long as there is no pressure at its pilot port. When the pilot port is pressurized, the valve will permit flow in either direction. The valve used in the boom lift circuit has a provision for manually releasing the load when no pressure is present at the pilot port.

These valves should be serviced as complete units on either a new replacement part or service exchange basis.

PILOT OPERATED CHECK VALVES FIGURE 108 SHUTTLE VALVES - Shuttle valves (Figure 109) are used in the roof bolter's tram circuit. These valves allow both working ports of the front tram valve to be connected to the parking brakes while preventing flow from one working port to the other. The operation of a shuttle valve is illustrated below (Figure 109).

SHUTTLE VALVE FIGURE 109

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FLOW CONTROL VALVE - Flow control valves (Figure 110) are used in the boom feed and drill rotation circuits for speed control. The cross section of a flow control valve is illustrated below.

These valves are of the variable orifice type, and incorporate a check valve for free flow in the reverse direction. The end of the valve stem is tapered, so that as it is withdrawn from the valve seat the area, available for flow increases.

FLOW CONTROL VALVE FIGURE 110

131

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RB2-88 ROOF BOLTER

FLOW LIMITERS - Flow limiters (Figure 111) are used in the roof bolter's tram circuits for limited slip action, and at various other locations. These flow limiters have virtually no effect on flow until the unit's rating is reached. As the flow increases to the limiting value, the regulating action of the limiter comes into play. A pressure drop across the orifice (1) in the piston (2) causes the piston to move against the tension of the spring (3). Even the slightest increase in flow will cause the piston to move further to the right, decreasing the throttling area (4). The decreased throttling area restricts flow to compensate for the variation. By this method, the flow limiter restricts flow to a fixed value regardless of pressure variations.

FLOW LIMITER FIGURE 111

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HYDRAULIC JACKS - (See Figure 112) A variety of hydraulic jacks are used for various functions on the roof bolter. Depending on the function, some are single-acting (cradle lift for example) and others are double-acting (boom lift, for example).

Basically, all hydraulic jacks consist of a barrel with two end caps, a piston, and a piston rod.

The end cap of the jack from which the piston rod protrudes is the "rod end”, and the other end is the "blind end”.

When hydraulic fluid enters the blind end port (A) of a hydraulic jack, the fluid pushes the piston in the direction which causes the piston rod to extend, and the jack extends. When hydraulic fluid enters the rod end port (B) of a double-acting hydraulic jack, the fluid pushes the piston in the direction which causes the piston rod to retract into the cylinder barrel, and the jack retracts. Single-acting hydraulic jacks are retracted by simply providing the hydraulic fluid in the blind end of the jack with a route for escape, and allowing the weight of the object lifted to physically push the jack closed, forcing the hydraulic fluid from the blind end of the jack in the process. Hydraulic jack thrust is a function of oil pressure, and jack speed is determined by the volume of oil flow.

TYPICAL HYDRAULIC JACK FIGURE 112

133

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RB2-88 ROOF BOLTER

HYDRAULIC FLUID FILTER - Two hydraulic filters (Figure 113) are used in the roof bolter's hydraulic system. Both are of the low pressure type, and filter the hydraulic fluid returning to tank.

Oil enters each filter through the inlet port and moves between the filter housing and the element. As long as the element is clean, oil then passes through the element where any contaminants are trapped. The oil then moves through the center of the filter and through the outlet port.

If the element is too clogged for the oil to get through, pressure builds up at the inlet port until it forces the bypass valve poppet off its seat. Dirty oil then passes directly to the outlet port and into the tank.

These filters are equipped with dirt alarms. Once the element becomes restricted, the indicator will turn red, indicating the element is clogged and requires changing. After changing the element, the indicator's button must be reset by pushing in on the button.

HYDRAULIC FLUID FILTER FIGURE 113 PRESSURE GAUGES - A group of pressure gauges (Figure 114) provides the operator with a constant means of oil pressure measurement in individual circuits. The group of gauges consists of four gauges and a gauge block.

PRESSURE GAUGES FIGURE 114

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SECTION 6 - ELECTRICAL FUNCTIONS

GENERAL ELECTRICAL SCHEMATIC SYMBOLS FIGURE 115

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GENERAL This section of the manual is divided into three parts: General Sequence of Operation, AC Machines Electrical components RB2-88 roof bolters use 660 vac power sources. The machines are equipped with two electric motors. Each motor powers a dust collection blower from one end, and a hydraulic pump from the other end. Standard machines are equipped with two headlights (one at each end).

Available optionally are complete illumination systems utilizing flourescent lamps.

The RB2-88 roof bolter starter box (controller) has two overload relays which are used for motor protection. Each motor uses a single relay: all three phase leads pass through the relay's heaters.

SEQUENCE OF OPERATION, AC MACHINE (Refer to Schematic and Wiring Diagram, Figures 116 and 117) Provided the trailing cable is energized, throwing the circuit breaker handle to the "ON” position (you may need to reset it first) makes power available to the line side contacts of the motor starter. At the same time, power is made available to the primary windings of a step down transformer. The secondary coil of this transformer (24v) supplies the control circuit and the headlight circuit. Two fuses protect the headlight circuit, the control circuit, and the secondary winding of the transformer.

Pushing either start button (they're wired in parallel) supplies current to the coil of the motors' linestarter, through the normally closed contacts of the thermal overload relays. (These overloads are in series, so that if anyone trips, the circuit is broken.) Once the starter is energized, main contacts in the starter close to complete the line voltage circuit to the motors. At the same time auxiliary contacts close to bridge the start button so that the button can be released without deenergizing the linestarter.

The motors will stop if any of the following occur: • any stop button is pressed (this breaks the 24 -volt circuit to the linestarter coil).

• the circuit breaker trips or is switched off (this breaks the three phase line circuit).

• any overload trips (this breaks the 24 volt circuit to the linestarter coil).

The headlights are energized through a double pole double throw switch. This switch has three positions (FWD, OFF, REV) and will energize the front, the rear, or either headlight, depending on its position.

136

RB2-88 ROOF BOLTER

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ELECTRICAL SCHEMATIC, AC FIGURE 116

137

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RB2-88 ROOF BOLTER

ELECTRICAL WIRING DIAGRAM, AC FIGURE 117

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AC MOTOR - The electric motors used on AC roof bolters (Figure 118) are air cooled, three phase, squirrel cage units utilizing explosion proof housings. They are supplied with 440v 60hz.

The stator shaft is supported on ball bearings, and grease channels are provided for lubrication of these bearings.

TYPICAL 30 KW AC MOTOR FIGURE 118

139

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STARTER (CONTROLLER) BOX (AC) - The starter box (Figure 119) contains the circuit breaker, motor starter, headlight switch, overload relays and control transformer. These components are described on the following page. The starter box case is an MSHA approved explosion proof enclosure, and must be maintained in good condition to remain permissible.

STARTER BOX (CONTROLLER), AC FIGURE 119

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STARTER BOX COMPONENTS, AC MACHINES CIRCUIT BREAKER - The circuit breaker used on AC roof bolters is the thermal magnetic trip type. It can be tripped by either a long term slight overload or a short term severe overload. The breaker's continuous rating is 225 amps. The instantaneous trip is set at 500 amps.

STARTER - The starter is a standard three pole magnetic contactor equipped with thermal overload relays. The starter's contacts are of the double break type, and are silver alloy faced.

The movable contacts are attached to an arm which is in turn attached to a movable armature, via a rod and bracket. When the contactor coil is energized, the armature is drawn upward, forcing the movable contacts into firm contact with the stationary contacts. Contact springs, between the contact arm and the movable contacts, ensure uniform contact pressure.

HEADLIGHT SWITCH - The headlight switch is mounted to the side of the starter box. The switch is a rotary, dual pole dual throw (three position) design. It can serve to energize either the front or rear headlight and has a center "OFF" position.

TRANSFORMER - The transformer is mounted to the back of the starter box, and provides a 24 volt supply for the control circuit and the headlight circuit. Two fuses are mounted from the transformer, and serve to protect both the transformer secondary and the headlight and control circuitry from excessive current.

THERMAL OVERLOAD RELAY - The thermal overload relay reacts to long term overloads in the motor circuit. Overload protection is provided by a switch actuated by a bimetallic snap action disc. This disc consists of two dissimilar metals laminated together and pressed into a concave shape. When heated to a predetermined temperature by a heating element, the disc snaps into its convex position, opening the switch contacts. The heating element (heater) is in series with the motor: current flowing through the motor must also flow through the heater. A long term overload will cause the temperature of the heater to rise to a point sufficient to trip the overload switch.

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CONTROL STATION SWITCH (START/STOP SWITCH) - The control switch assembly (Figure 120) consists of two momentary contact pushbutton switches (one normally open, and one normally closed) contained in an MSHA approved explosion proof enclosure. The switch actuating pushrods are adjustable to provide for positive action while allowing for manufacturing tolerances. Like any explosion proof enclosure, this component must be maintained in good condition to remain permissible.

CONTROL STATION SWITCH FIGURE 120

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DBT AMERICA

EMERGENCY STOP SWITCH - The emergency stop switch (Figure 121) consists of a momentary action, normally closed, pushbutton switch housed in an MSHA approved explosion proof enclosure. The emergency stop switch must be maintained in good condition to remain permissible.

EMERGENCY STOP SWITCH FIGURE 121

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RB2-88 ROOF BOLTER

CABLE REEL - The cable reel (Figure 122) provides a method for controlling the machine's trailing cable. The cable is pulled off the reel as the machine moves forward. When the machine backs up, the operator actuates the hydraulic reel motor control valve, and the trailing cable is retrieved under controlled tension. A collector assembly (housed within an explosion proof enclosure) serves to provide an electrical connection between the trailing cable and the machine's circuits.

CABLE REEL FIGURE 122

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THE DBT AMERICA PRODUCT FOR WHOM THIS MANUAL WAS PREPARED WAS DESIGNED AND BUILT TO PROVIDE RELIABLE PERFORMANCE UNDER TYPICAL MACHINE OPERATING CONDITIONS. DBT AMERICA DESIGNERS AND ENGINEERS HAVE CAREFULLY DEVELOPED OR SPECIFIED EACH PART WITH MATERIAL COMPOSITION AND TOLERANCES APPROPRIATE TO THE PART'S INTENDED USE. THIS PRODUCTS' MSHA CERTIFICATION WAS GRANTED BASED ON THE INCORPORATION OF APPROVED DBT AMERICA PARTS. DBT AMERICA IS COMMITTED TO PROVIDING THE BEST SERVICE AND SUPPORT TO ITS CUSTOMERS. THAT IS WHY IT HAS:

• DEVELOPED, SELECTED AND MADE AVAILABLE TECHNICALLY CORRECT AND APPROVED REPLACEMENT PARTS FOR ITS PRODUCT LINES.

• ESTABLISHED AN EFFECTIVE NETWORK OF SALES AND SERVICE FACILITIES IN THE U.S. AND ABROAD.

• INSTALLED AND MAINTAINS A COMPUTERIZED PARTS STOCKING SYSTEM TO ENSURE HIGH AVAILABILITY LEVELS REPLACEMENT COMPONETRY AND SUBASSEMBLIES.

FOR

• ADOPTED A UNIQUE CHANGEOUT SYSTEM COVERING MAJOR COMPONENTS TO MINIMIZE CUSTOMER COSTS AND DOWNTIME.

WE RECOMMEND THAT YOU PURCHASE DBT AMERICA RENEWAL PARTS TO MAINTAIN YOUR EQUIPMENT IN ITS ORIGINALLY APPROVED CONDITION, A MANDATORY MSHA REQUIREMENT. SINCE MSHA REGULATIONS MAKE IT INCUMBENT UPON THE MINE OPERATOR TO MAINTAIN ALL PERMISSIBLE EQUIPMENT AND MACHINERY IN ITS APPROVED CONDITION, IT IS ESSENTIAL THAT PROPER PROCEDURES AND REPLACEMENT PARTS ARE USED DURING REPAIR OR REBUILDING OF APPROVED EQUIPMENT AND MACHINERY.