Cat Electric Rope Shovel 7295 Engineering Data Manual – PDF DOWNLOAD

Engineering Data BI011160

8

Engineering Data

Always refer to the safety information in Section 1 of this manual before starting any maintenance procedure on this machine.

Capscrew (Bolt) Grade ............................................................................................................... 3 Bolt Tightening ........................................................................................................................... 4 Torque Wrench Method ........................................................................................................... 4 Table 1 - Lubricated or Plated Threads or with Hardened Washers .............................................. 4 Table 2 - Dry Threads .................................................................................................................. 5

Turn-of-nut Method .................................................................................................................. 6 Table of Snug Tight Torque Values ............................................................................................. 6

Split Flange Assembly Procedure ............................................................................................. 8 Torque Table For Split Flange Assembly .................................................................................... 10

Wire Locking Capscrews ......................................................................................................... 11 Patterns for Wirelocking Capscrews .......................................................................................... 11

Procedure For Use Of Mechanical Tensioner On Crawler Rods .......................................... 12 Connecting Rods - Crawlers to Truck Frame .............................................................................. 13

Torque Nut Removal Procedure ............................................................................................. 14 Thread Lubrication................................................................................................................. 14 Torque Nut Helpful Hints ......................................................................................................... 15 Locking Assemblies .................................................................................................................. 16 Locking Assembly Removal .................................................................................................. 18 Pinion And Hub Installation ...................................................................................................... 19 Removal From A Shaft .......................................................................................................... 19 Mounting A Pinion Or Hub On A Shaft .................................................................................... 19 Hub Adapter Pre-heat Advance Requirements ................................................................ 22 Motor Coupling Pre-heat Advance Requirements ............................................................ 23 SM141490-EN

7295 Electric Rope Shovel

8-1 November 2012

Engineering Data BI011160

Maintenance Welding ............................................................................................................... 24 Welding Electrodes ............................................................................................................... 25 Repair Welding Of Cracks .................................................................................................... 26 Joint Preparation for Repair of Cracks ....................................................................................... 26

Preheat ............................................................................................................................ 27 Welding Technique .......................................................................................................... 28 Repair Welding Of Broken Parts ........................................................................................... 29 Repair Welding Swing Rack Teeth ........................................................................................ 30 Preparation ...................................................................................................................... 31 Swing Rack Welding Electrodes ..................................................................................... 32 Preheat ............................................................................................................................ 32 Welding Procedure .......................................................................................................... 33 Welding And Cutting Equipment ............................................................................................. 35 Stress Relieving & Temperature Measuring Equipment ..................................................... 36 Wire Rope Care And Maintenance .......................................................................................... 38 Storage .................................................................................................................................. 38 Checking Diameter ................................................................................................................ 38 Correct Method for Checking Wire Rope Diameter ..................................................................... 38

Handling Wire Rope .............................................................................................................. 39 Improper Methods for Uncoiling Wire Rope ................................................................................ 40

Seizing Wire Rope ................................................................................................................ 41 End Preparations/Terminations ............................................................................................. 43 Wire Rope Clips .................................................................................................................... 44 Wire Rope Clip Application .............................................................................................. 45 Wedge Sockets ............................................................................................................... 47 Inspection of Sheaves and Drums ........................................................................................ 48 Examples of Sheave Groove Conditions ..................................................................................... 48 Groove Gauge for New or Re-Worked Sheaves .......................................................................... 49 Inspecting for Worn Sheave ....................................................................................................... 50

Breaking In A New Wire Rope ................................................................................................ 50 Inspection Data ..................................................................................................................... 50 Guideline to Inspections and Reports .............................................................................. 51 Wire Rope Stretch vs. Rope Life ................................................................................................55 Examples of Broken Wires ........................................................................................................ 58

Seals ........................................................................................................................................... 59 Seal Installation ..................................................................................................................... 59 Split Seal Installation ................................................................................................................. 60

Gearcase Sealing .................................................................................................................. 61

8-2 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Capscrew (Bolt) Grade The grade classification of a capscrew (bolt) is identified by the marks on the head as shown below:

Use the SAME GRADE washer and nut as the capscrew. NEVER SUBSTITUTE A LESSER GRADE CAPSCREW IN PLACE OF THAT WHICH IS SPECIFIED.

SM141490-EN

7295 Electric Rope Shovel

8-3 November 2012

Engineering Data BI011160

Bolt Tightening Torque Wrench Method The following tables show torque values for bolt grades 2, 5 and 8 with UNC threads only. Table 1 lists torque values for lubricated or plated threads and for using hardened washers. Table 2 lists those for dry threads.

Table 1 - Lubricated or Plated Threads or with Hardened Washers

8-4 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Table 2 - Dry Threads

The bolts should be tightened to the specified total value in increments, alternating from bolt to bolt to assure gradual, even pull-up of mating parts. Tightening should progress systematically from the most rigid part of a joint to its free edges.

Circular bolt patterns should be tightened in a diametric crosshatch pattern while applying torque in increasing values to ensure proper pull-up of parts.

SM141490-EN

7295 Electric Rope Shovel

8-5 November 2012

Engineering Data BI011160

Turn-of-nut Method

THIS TIGHTENING PROCEDURE IS ONLY APPLICABLE FOR BOLT GRADES 5 AND 8 WITH UNC THREADS. For bolts with other than UNC threads, contact the manufacturer.

NOTE: When using this procedure the bolt threads and the surfaces under the bolt head and nut must be lubricated. This procedure is applicable only if the joint and under head surfaces for bolt and nut are machined for parallelism.

1.

The bolts should be brought to a “snug tight” condition to ensure that the parts of the joint have good contact with each other. “Snug Tight” is defined as the tightness attained by torquing a bolt to the value specified in the table on the following page. Snug tightening should progress systematically from the most rigid part of the joint to its free edges while alternating from bolt to bolt to assure gradual even pull up of the mating parts. After all bolts have been snugged, the first bolts tightened at the most rigid part of the joint should be rechecked for proper torque retention. If these bolts are loose due to pull up of the joint, the snug tightening sequence should be repeated for all bolts in the connection. This rechecking and re-torquing procedure should be repeated as many times as is required until the joint is completely pulled up and all bolts are at the specified “snug tight” torque.

Tightness of the mating surfaces of the joint should then be verified by using feeler gauges.

Table of Snug Tight Torque Values

8-6 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

2.

The nuts and bolts should then be matched marked by center punching the bolt end and nut. On rod bolts match mark both rod ends and nuts. The bolts and nuts should then be tightened additionally by the applicable amount of nut rotation as specified in chart above. It is not necessary to follow any particular bolt to bolt sequence during this portion of the “turn of the nut” tightening.

NOTE: Nut rotation is read between the punch mark on the bolt and the punch mark on the nut.

For rod bolts, nut rotation is the cumulative total rotational movement between punch marks on both ends of the rod bolt.

SM141490-EN

7295 Electric Rope Shovel

8-7 November 2012

Engineering Data BI011160

Split Flange Assembly Procedure

The 4 bolt split flange connection consists of four main components.

— Body of Flange Head (part of hose or tube) — O-Ring — Pair of Split Flange Clamps — Bolts and Lockwashers To assemble split flange connection: 1.

Ensure that all sealing surfaces are free of burrs, nicks, scratches or any foreign particles.

2.

Lubricate the o-ring with light grease or oil and insert into groove.

3.

Position flange head and clamp halves.

4.

Apply retaining compound to the bolt threads. Place lock washers on bolts and insert through clamp halves.

5.

Hand tighten bolts.

8-8 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

NOTE: Refer to the TORQUE TABLE for proper torque values. All torque values apply to Grade 5 (Metric Grade 8.9) hardware or above with lubricated threads.

6.

Tighten all bolts in a diagonal sequence in three incremental steps. Use the appropriate torque value specified in the TORQUE TABLE.

7.

Clean components before marking, then apply a legible mark with a permanent marker or paint across each bolt and clamp.

SM141490-EN

7295 Electric Rope Shovel

8-9 November 2012

Engineering Data BI011160

Torque Table For Split Flange Assembly

8 - 10 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Wire Locking Capscrews Wire locking of capscrews is used when maximum lock assurance is required when periodic visual inspection is not possible.

The illustrations below show the recommended wire locking methods for various right hand thread capscrew patterns. For patterns not shown, wire lock the screws “in pairs”. For odd numbered patterns, wire lock the screws in pairs except the remaining 3 capscrews wire lock together

Patterns for Wirelocking Capscrews

Use 14 gauge soft annealed lock wire. Thread the wire through the capscrew head so that tightening stress on the wire will exert a tightening torque on the direction of capscrew thread. (The illustrations show lock wire threading for right hand threaded capscrews. Reverse the lock wire patterns shown for left hand capscrews.)

SM141490-EN

7295 Electric Rope Shovel

8 - 11 November 2012

Engineering Data BI011160

Procedure For Use Of Mechanical Tensioner On Crawler Rods NOTE:

Steps 2 - 5 are to be done in the rod sequence pattern shown below.

1.

Lubricate the threads and spin the tensioner onto the main thread until it seats against the washer (supplied with the torquenut).

2.

Tighten 4 jackbolts at 90° apart as indicated in Sequence Fig. 1 on all studs with a partial torque (88 Ft-Lbs). This serves to seat the flange. If using an air impact, use a reduced setting or lightly pulse the trigger at the full setting.

3.

At 100% target torque, (175 Ft-Lbs), tighten the same 4 jackbolts on all the studs.

4.

At 100% target torque, (175 Ft-Lbs), tighten all the jackbolts in a circular pattern as shown in Sequence Fig. 2. Tighten jackbolts on all the studs.

5.

Repeat Step 4 until all jackbolts are stabilized (less than 10° rotation). This usually requires 2-4 additional passes. If using air tools, switch to a torque wrench when socket rotation is small. Use the torque wrench to stabilize at the target torque (175 Ft-Lbs).

6.

Repeat Step 5 for all studs after 20 hours of digging operation.

8 - 12 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Connecting Rods - Crawlers to Truck Frame

SM141490-EN

7295 Electric Rope Shovel

8 - 13 November 2012

Engineering Data BI011160

Torque Nut Removal Procedure

THE PROPER REMOVAL OF TORQUE NUTS REQUIRES FOLLOWING STRICT PROCEDURES. LONGER ANCHOR BOLTS AND RODS REQUIRE GREATER CARE. If some jackbolts are completely unloaded prematurely, the remaining jackbolts will carry the entire load of the fastener. This may cause the jackbolts to become extremely hard to turn or even deformed.

NOTE: It is a good practice to spray the entire fastener and jackbolts with a penetrating type lubricant prior to attempting removal. This step will be critical if rust exists on the components.

1.

Turn the first jackbolt counter-clockwise until it feels loose, but no more than 1/2 turn.

2.

Repeat the loosening with the rest of the jackbolts. Use the reverse of the star pattern used to tighten the jackbolts. This will minimize loading on the last few jackbolts.

3.

Repeat the entire loosening pattern, turning each jackbolt no more than 1/2 turn at a time, until the torque nut can be spun off the rod or bolt by hand.

After removal of the torque nut: •

Remove all jackbolts from the torque nut. Clean, inspect and lubricate the toque nut, hardened washer and the jackbolts for later reassembly.

NOTE: On smaller torque nut fasteners it may be possible to utilize impact tools to speed removal after performing step 2 above. However, DO NOT USE IMPACT TOOLS FOR THE INITIAL LOOSENING PROCEDURE. Longer anchor bolts may require several repetitions of the initial loosening process prior to switching to impact tools for assistance.

Thread Lubrication For the main studs of torque nut fasteners any standard anti-seize compound may be used. A thin, brush-on type application, or aerosol spray lubricant is acceptable.

Jackbolts are pre-lubricated from the factory with either moly or graphite lubricants depending on the intended use. Ensure lube is present on these surfaces and apply additional lube (PN: MP390331) as needed. Similar lubricants may be used on the jackbolt tips and hardened washer during installation.

8 - 14 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Torque Nut Helpful Hints Prior to Tightening: 1.

Threads: Check all threads of the main stud to verify that the torque nut will spin on freely prior to installation. If a restriction is found, use a lapping compound on the main threads or chase the threads in either the torque nut or the main stud using a good die or tap. THE UNRESTRICTED MOVEMENT OF THE torque nut ON THE MAIN STUD IS CRITICAL IN THE INSTALLATION PROCESS.

2.

Spacers: The torque nut should be positioned at the end of the main stud when installation is complete in order to minimize exposed threads which could be damaged. This will also serve to minimize any difficulty in reaching the jackbolts and avoid the need for thinwall, or deepwell sockets. A spacer or stacked washers can be used beneath the hardened washer to accomplish this. The spacer will also allow a step-over of a damaged area on stud from repeated installations.

3.

Gaps: Back off the torque nut to provide a gap of 1/16 to 1/8 inch between the torque nut and the hardened washer prior to beginning the torque application process. This will allow additional jackbolt extension which provides easy access for jackbolt tip lubrication prior to removal. When closing a gap between flanges, or where long fasteners are used, there may be insufficient jackbolt stroke to allow this step.

4.

Sockets: Use only six-point quality sockets in good condition. Worn sockets will eventually round out the corners of the jackbolts possibly causing damage or injury.

While Tightening: 5.

Do not tighten a jackbolt completely prior to moving on to the next jackbolt. As the torque nut is tightened, the first jackbolt that was tightened in that sequence will have a tendency to loosen. It will be faster to make multiple passes by moving quickly between jackbolts.

6.

Overshoot the Target Torque as indicated PRIOR to the final tightening. This will quicken the tightening sequence by stabilizing previously tightened jackbolts sooner. BE CERTAIN NOT TO “STABILIZE” THE JACKBOLTS AT THIS HIGHER TORQUE VALUE!

While Removing: 7.

Removing the jackbolts too quickly during disassembly may increase the removal torque of the remaining jackbolts. If a jackbolt should become jammed, re-tighten several jackbolts to either side to even the tension on the torque nut.

8.

If a jackbolt tip “mushrooms” its tip must be cut off with a cutoff wheel or abrasive disc, then the jackbolt removed.

SM141490-EN

7295 Electric Rope Shovel

8 - 15 November 2012

Engineering Data BI011160

Locking Assemblies To install a locking assembly:

1.

Clean and lightly oil all parts of the locking assembly, the shaft or pin and the housing bores.

Be sure the bores to be connected are properly aligned.

2.

Loosen all socket head capscrews on the locking assembly.

3.

Install the locking assembly and the shaft or pin into the housing. Carefully note any measurements required to align the locking assembly.

8 - 16 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

4.

Tighten the capscrews of the locking assembly evenly. Do not tighten each screw all at once. Instead, gradually tighten each one and proceed with the entire set, using a crisscross pattern, and repeat until all screws are tight. Refer to the proper section of the maintenance manual for the specific torque required.

Where pilot bushings are used: 1.

Insert the locking assembly as stated above - except remove all socket head capscrews.

2.

Insert 3 pilot bushings, equally spaced. Insert the longer capscrews supplied with the pilot bushings.

3.

Tighten the capscrews using the same procedure required for the locking assembly capscrews.

4.

Once the pilot bushing is has been properly tightened, remove the longer socket head capscrews and the pilot bushings. Replace the capscrews in the locking assembly with the socket head capscrews that came with the locking assembly.

5.

Tighten all capscrews using the procedure above. Retain the pilot bushings and longer capscrews for future use.

SM141490-EN

7295 Electric Rope Shovel

8 - 17 November 2012

Engineering Data BI011160

Locking Assembly Removal

For series 1015 assemblies with a center collar: 1.

Loosen all capscrews on the locking assembly by at least 2 turns in 1/4 turn increments.

2.

Transfer all the capscrews to the push-off threads provided in the clamp collar and in the center collar.

3.

Progressively tighten all screws in a diametrical pattern - except the screws adjacent to the slit in the clamp collar - these should be tightened one after the other.

For series 4000 assemblies with NO center collar: 1.

Loosen all capscrews on the locking assembly by at least 2 turns in 1/4 turn increments.

2.

The locking assembly incorporates a self-releasing taper, which should allow the assembly to be removed. However if the thrust rings jam, tap on the heads of 3 equally spaced capscrews to positively release the connection.

3.

Insert pullout screws in the threads under the cadmium plated locking screws to remove the assembly.

8 - 18 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Pinion And Hub Installation Removal From A Shaft

A properly mounted pinion, brake drum or coupling will have an interference fit with the shaft causing it to release suddenly and violently when broken loose. Loosen the shaft nut just enough to allow the pinion, brake drum or coupling to free itself. The shaft nut will stop the pinion or coupling and avoid injury to personnel.

NOTE: When removing the pinion, brake drum or coupling from a motor shaft, always use a suitable puller to avoid causing damage to either the pinion, coupling, motor frame, bearings or shaft. Do not heat the pinion, brake drum or coupling before pulling and do not use wedges between them and the bearing cap. To prevent damage to the antifriction bearings, avoid the use of a sledge hammer on the puller.

Mounting A Pinion Or Hub On A Shaft Successful operation of the gearing largely depends on the proper mounting of the pinion, brake drum or coupling on the shaft.

NOTE: Mounting pinions, brake drums or coupling by heating them in boiling water and driving them on the shaft with a blow from a heavy sledge hammer is not recommended. This results in uncontrolled advance of the pinion or coupling on the shaft. Too great an advance can cause breakage of the pinion, brake drum or coupling core, while insufficient advance can cause slippage and wear in spite of the presence of the key. In addition, hammer blows can injure the finished surface of the anti-friction bearings.

Pinions, brake drums or couplings must be mounted to a definite advance on the shaft, without hammer blows. This requires heating them to a higher temperature than is obtainable with boiling water, and is based on a difference in temperature between them and the shaft. The following is the recommended method for mounting pinions, brake drums or couplings: 1.

Thoroughly clean the pinion, brake drum or coupling seating surface on the shaft and the bore of the pinion, brake drum or couplings. Use toluol or percholoethylene; do not use kerosene.

Solvents may be toxic or flammable. Adequate ventilation must be provided to minimize fire and health hazards. Use away from sparks, heat or flame to prevent fire or explosion. Follow the manufacturer’s instructions.

SM141490-EN

7295 Electric Rope Shovel

8 - 19 November 2012

Engineering Data BI011160

2.

Remove any scoring from either part. Spot the cold pinion, brake drum or coupling on the shaft by hand to obtain at least a 75% fit. Check the fit with bluing. Remove the pinion, brake drum or coupling.

3.

Break all sharp edges of the key and the keyway with a fine file, so there will be a radius of about 1/64 inch at each edge. Fit the key to the shaft, taking care to avoid upsetting the metal of the shaft adjacent to the key. If previously upset, file lightly, checking the fit with bluing until a 75% fit results. Try the pinion, brake drum or coupling on the shaft to make certain it does not bind on the key.

4.

Mount the pinion, brake drum or coupling cold by placing it on the shaft and snapping it into position by hand. Measure the “cold” position of the pinion, brake drum or coupling using a micrometer depth gauge. Mark the places where the depth gauge was resting so measurements can be made from the same position after the pinion, brake drum or coupling has been mounted. The following figure illustrates the method of using the depth gauge.

5.

Remove the pinion, brake drum or coupling from the shaft and heat it in a suitable oven to the temperature specified. If the pinion, brake drum or coupling is heated in oil, the bore must be thoroughly cleaned before mounting. To avoid the cleaning, the use of an oven is recommended.

Use suitable protective equipment when handling hot items.

The pinion, brake drum or coupling temperature is indicated as a temperature difference between the shaft and pinion; this temperature difference is estimated only and can be adjusted to maintain the specified advance. Heat the pinion, brake drum or coupling in the oven until the temperature is uniform at the required number of degrees above the shaft temperature. For example, if the shaft temperature is 25oC (77oF) and the estimated difference is 125oC (225oF), heat the pinion, brake drum or coupling to 150oC (320oF) for mounting.

8 - 20 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Pinion, brake drum or coupling temperature must never exceed 190oC (374oF).

Some accurate method must be provided for quickly measuring the temperatures of the pinion, brake drum or coupling and shaft before mounting them. This is best done with a hand pyrometer (refer to the figure). When a hand pyrometer is not available, a centigrade thermometer can be used by placing putty over the bulb to hold it against the pinion or coupling. Heat the pinion, brake drum or coupling a few degrees above the desired temperature before removing it from the oven. Wait until it has cooled to the temperature desired, remove the thermometer and quickly mount the pinion, brake drum or coupling as described below.

6.

After making sure the bore is clean, quickly mount the hot pinion, brake drum or coupling on the shaft. When it is nearly engaged with the taper fit (but not actually in contact), snap it forcible into place with a quick push. It is important that the hot pinion, brake drum or coupling be instantly snapped into position before it has cooled appreciably; otherwise it will immediately “freeze” to the shaft and cannot be adjusted further.

7.

Check the “hot” or shrunk-on position of the pinion, brake drum or coupling on the shaft, using the micrometer depth gauge. The actual advance is the difference between depth gauge readings at the hot and cold positions. To control the stresses in the pinion, brake drum or coupling, the advance must be within the limits specified in the table below.

If the advance is not within the limits given, the pinion, brake drum or coupling should be pulled and remounted.

8.

Assemble the lockwasher and nut, tighten firmly and lock. Where a lockwasher is not used, retaining compound must be used to keep the nut tight during operation.

When a lockwasher is used, the nut must be firmly tightened against it, then the tab on the lockwasher must be bent against the flat of the nut. This is required to keep the nut tight during operation.

SM141490-EN

7295 Electric Rope Shovel

8 - 21 November 2012

Engineering Data BI011160

Hub Adapter Pre-heat Advance Requirements

8 - 22 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Motor Coupling Pre-heat Advance Requirements

SM141490-EN

7295 Electric Rope Shovel

8 - 23 November 2012

Engineering Data BI011160

Maintenance Welding These recommendations for repair welding apply to the major structural members of the machine.

The high cyclic loading characteristics of the machine are considered in the design and material selected for the construction of the machine. However, due to unusual operational conditions that may be encountered and to the great number of cyclic loadings that may be applied to the machine, fatigue cracks or other abnormalities may occur. Early detection of these conditions through regular machine inspection helps to avoid problems or emergency breakdowns.

Maintenance welding is applied to the repair of cracked or broken structural components.

Reconditioning of broken parts by the application of heating, cutting and welding processes requires attention to a number of details, careful adherence to the repair procedure and observance of federal, state and local safety regulations.

WELDING AND THERMAL-CUTTING OF METALS INVOLVE THE GENERATION OF TEMPERATURES UP TO THOUSANDS OF DEGREES AT WHICH METALS MELT AND VAPORIZE. When proper precautions are taken to protect personnel and property against the heat, evolved gases and fumes, electric shock and radiation, no harm will result either to personnel or property. In gas heating and cutting, the handling and storage of compressed gases present other hazards that also must be protected against to provide a safe working environment.

Safety precautions should conform to the latest edition of ANSI standard Z49.1, Safety in Welding and Cutting, published by the American Welding Society.

Reconditioning of failed members requires attention to a number of details and careful application of the repair procedure. Only in certain cases is it necessary to strengthen members by added reinforcement.

REINFORCING STRUCTURAL MEMBERS SHOULD BE MADE ONLY UPON RECOMMENDATION BY THE MANUFACTURER. IMPROPERLY APPLIED REINFORCEMENTS CAN HAVE AN ADVERSE EFFECT ON THE PERFORMANCE AND LIFE OF THE STRUCTURE. A broken member is best repaired by making a complete penetration weld, preferably by welding from both sides, using the correct welding electrode and observing all precautions such as preheat, back-gouging, etc. The complete penetration groove weld should be ground flush with the base metal on both sides to remove all surface irregularities. An alternate procedure incorporates backup bars to ensure sound, complete penetration welds in the repair area. Be sure to follow all applicable safety measures and federal, state and local regulations.

8 - 24 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

A complete penetration weld repair conditioned by grinding instead of adding reinforcement is favored to maintain the original pattern of stress flow designed into the structural members. Addition of reinforcement which is not part of the design can reduce fatigue strength because of the change in geometry from the original structure.

Effective repair welding of cracked, broken or bent structural members of the machine involves knowledge of the types of steel used, proper welding electrodes and recognized good welding practice. The chemical composition, mechanical properties and thickness of the steel determine the welding electrode to be used and the preheat temperature required.

Welding Electrodes With the exception of the boom, weld repairs on the various structures of the machine can be made with two basic classifications of shielded metal arc electrodes: E7018 and E8018-C1. Both are low hydrogen electrodes which deposit weld metal having excellent properties at strength levels with 70,000 to 80,000 PSI, and impact properties from -20o to -75oF. These are all-position electrodes which produce high quality welds for repairing the structural components of heavy machinery.

NOTE: Although these electrodes are of superior quality, care must be exercised in their application. Low hydrogen electrodes are highly susceptible to moisture pickup after removal from sealed containers. To maintain low hydrogen, crack-resistant properties, they must be stored in electrode ovens at 250oF up to the time of use. Small portable rod ovens at the welder’s side are ideal. Use of dry low hydrogen electrodes cannot be over-emphasized.

Cracks caused by hydrogen are extremely fine and occur invisibly below the surface in the base metal heat affected zone, as shown. Therefore, they are not detectable at the time of welding.

SM141490-EN

7295 Electric Rope Shovel

8 - 25 November 2012

Engineering Data BI011160

These cracks can propagate in service and lead to ultimate failure of the part. It is necessary to adhere strictly to recognized good welding practice regarding the handling, storage and use of low hydrogen electrodes. To avoid underbead cracks, remove all oil or grease or other contaminates from the surface and be sure the steel is dry.

Preheat to the required temperature. Use only dry electrodes taken from the electrode oven. After exposure to the air, the electrodes must be returned to the oven. Time limit outside the oven is four hours for E7018 and two hours for E8018-C1 electrodes.

Repair Welding Of Cracks

Joint Preparation for Repair of Cracks

Remove the entire crack by arc air-gouging or grinding. Prepare a V-groove of approximately 4560o included angle for rewelding. If cracked through the full thickness and if it is possible to make the repair from both sides, a double V preparation is preferred. When welding from both sides, back-gouging for complete penetration is always recommended.

When it is not physically possible to back-gouge and weld the second side, an alternate approach must be taken. Sometimes it is possible to gouge through to completely remove the crack, then fit a backup bar on the underside to facilitate making a complete penetration weld.

NOTE: The backup bar must fit tightly to the underside otherwise poor welding conditions conducive to cracking may occur.

8 - 26 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

When it is not possible to fit a backup due to limited accessibility to the underside, it is advisable to remove a portion of the defective plate and weld in a new piece, using back up bars on all sides to ensure complete penetration welds.

A further alternative is to gouge through, removing the crack, and then weld small stringer beads to close the gap and prepare a groove for a repair weld. In this case, the repair weld will be essentially full penetration, but will be less than perfect on the under side. The other methods are preferred in the order described, that is, welding both sides, welding against a backup bar, or completely replacing a section of plate.

Preheat When preheating, apply heat to a broad, general area surrounding the repair location. A soaking heat that penetrates the material through its full thickness is preferred to high surface temperature quickly applied. Electrical resistance or radiant heating is suggested since the heat source can be left operating during welding to maintain the minimum preheat temperature. Preheat temperatures up to 400oF, depending upon the steel analysis, are adequate under most conditions for major repairs. As previously stated, preheat temperatures are determined by the type of steel in the structure. Temperatures should be measured with temperature indicating crayons.

SM141490-EN

7295 Electric Rope Shovel

8 - 27 November 2012

Engineering Data BI011160

Welding Technique

Maximum electrode sizes are 1/4 inch for flat position, 3/16 inch for horizontal position and 5/32 inch for vertical and overhead positions. Use a split weave as soon as bead width is large enough to accommodate beads side by side. Throughout all welding be certain thorough fusion with the base metal and adjacent weld beads is obtained on all weld passes. Clean off all slag between passes and all craters before starting the next electrode.

Inspect closely for cracks, undercut or overlap of beads, and gouge out or grind flaws where they occur before continuing. It is very important on highly loaded parts, particularly members subject to cyclic or dynamic stresses, to obtain sound repair welds.

The presence of any stress risers on the surface of a part is detrimental to fatigue life and can result in future cracking. Therefore, it is essential that the finished repair be smooth and well blended into the base metal. Repair weld any undercuts, grind off overlapped weld beads and blend out any notches or gouges. The best condition in a repair weld location is provided by grinding the repair smooth and flush with the surface of the base metal. Final grinding direction is to be identical with the direction of applied load on the structure. Refer to the figure.

8 - 28 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Repair Welding Of Broken Parts All recommendations given for repair of cracks apply to repair of broken parts, with additional corrections. Depending on the size and cross-section of the part, a specific sequence of welding procedures may be required in making the repair. These techniques include back-step welding sequence, block welding sequence, alternating from side to side, welding simultaneously on opposite sides, etc. All of these precautionary measures are intended to minimize shrinkage stresses and subsequent distortion or cracking during welding. The method to follow should be determined after a careful analysis of the situation and by approaching the problem with common sense. Generally a procedure which has proven successful in previous experience could logically be applied in most cases.

Use of doubling plates, stiffeners or other reinforcements to strengthen a member which has cracked in service, must be carefully considered before that repair measure is decided upon. Additional material added for strengthening alters the configuration and geometry of the member, possibly with a pronounced effect on the fatigue life of that structure. Many times, such attempts at strengthening by adding plates only serves to “chase the crack someplace else.” The stress flow in the part has been altered, creating a location for stress concentration. Attachments requiring fillet welds across a tension member for example, are poor repair methods. A sound repair weld, carefully made and smoothly blended into the base metal on all sides, is preferable to additional reinforcements. Any application of reinforcements requires careful consideration regarding total overall effect on the structure during service, and should be done only after consulting the manufacturer.

SM141490-EN

7295 Electric Rope Shovel

8 - 29 November 2012

Engineering Data BI011160

Repair Welding Swing Rack Teeth The following is a suggested method for the repair of cracked or broken swing rack teeth. The repair method should produce satisfactory results and provide a serviceable swing rack, provided the procedure is carefully followed in all details. The welding procedure is essentially the same for the three conditions shown.

8 - 30 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Preparation 1.

Clean off the swing rack in the area of the tooth to be repaired to remove all traces of grease, oil or dirt. Wash down thoroughly with a solvent cleaner and wipe dry with clean rags.

2.

Grind to completely remove the crack and prepare a groove for welding as shown in the figures.

3.

Dye penetrant test for complete crack removal.

4.

In the case of a broken tooth, grind the fracture surface on the swing rack smooth and round off edges as shown.

SM141490-EN

7295 Electric Rope Shovel

8 - 31 November 2012

Engineering Data BI011160

Swing Rack Welding Electrodes 1.

All welding is to be done using oven dry E11018-M low hydrogen electrodes. Connect an electrode drying oven as close as possible to the work area. Set the oven temperature at 300oF. As sealed containers of electrodes are opened, place the entire contents of the container in the oven. Remove no more electrodes than can be consumed in one-half hour.

If all electrodes are not used in 1/2 hour, return them to the oven. Discard any electrodes which have been wet.

Preheat 1.

Two levels of preheat are required for tooth repair, 250oF minimum for butter welding and 175oF minimum for filling in the groove. Temperatures should be measured with temperature indicating crayons.

2.

Preheat will be difficult to maintain because of the mass of metal in the swing rack to draw the heat away from the repair area. It is therefore recommended to apply heat to a large section of the swing rack to offset this quench effect. A section covering at least 3 teeth on either side of the tooth being repaired should be heated so that the minimum preheat temperature is obtained at the repair location. It is suggested that electrical resistance heaters be applied behind the teeth as shown, if such physical arrangement is possible. If the repair area cannot be heated to the required minimum temperature by this arrangement, supplementary heat must be applied from the tooth side of the swing rack.

Electrical resistance heaters can be applied, or heat provided by oxy-propane torches.

Adjacent areas of the swing rack should be covered with heavy insulation to avoid heat loss.

8 - 32 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

NOTE:

Contract services are available for field application of resistance heating equipment.

Suggested source: Stresstech Box 11 Red Wing, MN 55066 (612) 388-7117

3.

During welding, the repair area must be continually checked with temperature indicating crayons to be sure that the minimum temperature is being maintained. Do not weld at temperatures below the specified minimums.

Welding Procedure 1.

Refer to the previous butter-welding figures. The purpose of the butter weld layer is to provide a buffer between the weld required to fill the groove and the alloy cast steel. This technique is essential in preventing heat affected zone cracking in the cast steel which otherwise is likely to occur due to the shrinkage of the weld as the groove is filled. Butter welding permits the repair weld to be made at the preheat temperatures specified. Much higher temperature would otherwise be required for crack free welding.

2.

Butter welding is done using 1/8 inch diameter E11018-M electrodes at a minimum preheat temperature of 250oF. (See section under WELDING ELECTRODES regarding use of the electrode drying oven.) Horizontal weld beads are applied to completely cover the cavity or surface to be welded. The edges of the butter weld must overlap the adjacent surface about ½ inch. This is to prevent subsequent welding from impinging upon the cast steel.

3.

Before starting the butter weld, position a piece of thin mild steel plate under the bottom end of the tooth. This is to provide a shelf for starting the weld and to avoid irregular weld beads at the bottom which would become stress risers to cause cracking when the tooth is loaded in service.

4.

Apply the butter weld, progressing with horizontal beads from bottom to top. Use care to keep the butter weld layer as smooth and regular as possible. When finished, remove all slag and grind any high spot which could trap slag when welding to fill the groove. In the case of repairing a broken tooth the prepared tooth segment is butter welded separately before positioning for final welding in place.

5.

Filling the groove is done with 1/8 inch or 5/32 inch E11018-M electrodes at a minimum preheat temperature of 175oF. (See section under WELDING ELECTRODES regarding the use of the electrode drying oven.) Weld vertically up using a split layer technique as soon as the groove is wide enough to accommodate 2 or more beads. Refer to the butterweld figures for the approximate weld bead sequence.

6.

For replacing a tooth segment as shown, it will be necessary to prepare a tooth profile template. The template must be carefully made to fit the rack teeth as accurately as possible. Use the template to position the tooth segment prior to tack welding. When welding the tooth segment in place alternate welding from side to side to control distortion.

Check frequently with the template.

SM141490-EN

7295 Electric Rope Shovel

8 - 33 November 2012

Engineering Data BI011160

7.

When groove welding is finished check carefully for low spots and fill in as required. Grind the weld smooth and flush with the adjacent tooth surfaces. Use the tooth profile template to check grinding of a welded-on tooth segment. Grinding of the radius at the root of the tooth is very important. Avoid any nicks, gouges or grinding marks in a vertical direction.

Grind a smooth radius using small diameter (peanut) grinders. Failure to achieve a smooth, notch-free radius may result in future cracking at the root of the tooth.

8.

After the swing rack has cooled to ambient temperature, dye-penetrant test the repaired tooth for soundness.

8 - 34 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Welding And Cutting Equipment The welding and cutting equipment needed for general repair welding is listed below.

WELDING MACHINES, Arc - 600 ampere (for Welding and Air Arcing) OXY ACETYLENE TORCHES with Gauges - 150' Long Hoses HEATING TORCHES, Butane (for Boom Welding) ARC AIR ATTACHMENTS (for use with 600 Ampere Welding Machines) WELD RODS - E7018, E8018, E11018 - 1/8", 5/32". 3/16", 1/4" C02 - Welding Grade - 45oF Max. Dew Point OXYGEN - Cutting, and Heating ACETYLENE WELD FLUX CHIPPERS - Pneumatic with Chisels and Spare Parts BLOWERS, Ventilating (for Compartment Welding,) GRINDERS, Wheel - Air Powered w/Wheels TARPAULINS - Fireproof (for Boom Welding Shelters) HIGH TEMPERATURE GLOVES CUTTING GOGGLES, Dark SOAPSTONE MARKERS ANTI-SPATTER COMPOUND TEMPILSTIKS - 200o and 400o

SM141490-EN

7295 Electric Rope Shovel

8 - 35 November 2012

Engineering Data BI011160

Stress Relieving & Temperature Measuring Equipment The equipment recommended for stress relieving, after repair welding, is listed below.

TEMPERATURE MEASURING EQUIPMENT SPEEDOMAX, “W” Multipoint, Potentiometer Recorder POWER REQUIREMENT - 120 Volts, 60 or 50 Hz. RANGE - 0 to 1500oF CALIBRATION - Chromel-Alumel Thermocouple Wire ACCURACY RATING - 0.3% of Electrical Span CHART SPEED - 2" per Hour THERMOCOUPLE SELECTION - Six (6) Points FLUORESCENT LIGHTING MANUFACTURER - Leeds & Northrup Company THERMOCOUPLE EXTENSION WIRE DUPLEX WIRES - Chromel-Alumel - Type K - 16 AWG Stranded LENGTH - Total External Resistance for both Wires including Thermocouple not to exceed 2500 Ohms or 410 Feet.

WIRE RESISTANCE - Nominal Resistance, Ohm per Foot at 20oC (66oF) - Chromel - Ohms Alumel - .0683 Ohms.

WIRE INSULATION - each Conductor Enamel, Asbestos (Twisted Pair) Overall Asbestos Braid WIRE CODE -Alumel, Negative Wire (Red); Chromel, Positive Wire (Yellow) OVERALL COLOR - Yellow CATALOG No. 16-59-17 POLARITY DISCONNECT CHROMEL-ALUMEL COMPENSATED CONNECTION JACK Color Code (Yellow) - Catalog No. 040419 PLUG Color Code (Yellow) - Catalog No. 040434 CABLE CLAMP - Catalog No. 072513 ADAPTER - Catalog No. 076794 THERMOCOUPLE ELEMENT CHROMEL-ALUMEL - Type K - Swaged One (1) Inch Stripped CHROMEL POSITIVE WIRE Color Code (None) ALUMEL NEGATIVE WIRE Color Code (Red)

8 - 36 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

CATALOG No. 8784-K-1-3-12"-D 1.

588003 Kaopak Flex Heaters

2.

588004 Kaopak Collector Streamer Type

3.

Kaopak Blankets 3, 5, or 6 Pocket Size as needed for Size Pipe being Stressed Relieved

Thermocouple Assembly, Complete Catalog No. 8784-K-1-3-12"-Q Temperature Indicating Pellets (Tempil° Pellets) Indicating Temperature: 1050°F, 1100°F, 1200°F, and 1250°F. (Several of each temperature)

SM141490-EN

7295 Electric Rope Shovel

8 - 37 November 2012

Engineering Data BI011160

Wire Rope Care And Maintenance Storage Reels of wire rope stock may be kept on hand for a considerable length of time. This is particularly true of slow-moving special ropes that may not be disposed of completely for several years.

Consequently, wire rope should be stored in an area that is well-ventilated and stable with regard to temperature and humidity.

Do not store rope in contact with the bare ground or expose it to the elements. Excessive atmospheric vapors will condense moisture on the rope causing corrosion. If exposed to the direct sun, next to a boiler or in similarly warm conditions, the original lubrication will dry out and lose its preservation properties.

Similarly, storage in a dusty or chemical laden environment may coat the surface of the rope with corrosive materials or even deteriorate the fiber core. If it should be necessary to store rope outside, the reel should be set on blocks or raised off the ground, and covered with a waterproof covering.

Checking Diameter It is critical to check the diameter of the delivered rope BEFORE installation on the machine. This is to ensure that the rope diameter meets the specified requirements for the given machine or equipment. An UNDERSIZE diameter rope will bring about a condition where stresses are exceeding design limitations. This will increase the possibility of injury or machine damage as the chances of breaking the rope will be increased. Use of an OVERSIZE diameter rope will bring about premature wear of that rope. The rope constantly being pinched and compressed in the grooves of the sheaves and drum causes this.

Correct Method for Checking Wire Rope Diameter

When checking it is imperative that the actual rope diameter is measured. This is defined as the diameter of the circumscribing circle, or its largest cross-sectional dimension. To ensure accuracy this measurement should be made with a wire rope caliper to obtain the outside dimension of 2 diametrically opposing strands of the rope. When measuring a rope with an odd number of outer strands, special techniques must be employed. Refer to the manufacturer of the product for accurate information.

8 - 38 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Handling Wire Rope When re-reeling wire rope from a horizontally supported reel to a drum, keep in mind that a wire rope has a “memory” to be considered. If at all possible, it is preferable for the rope to travel from the top of the reel to the top of the drum during this process. The same would hold true for the bottom of the reel to the bottom of the drum. Re-reeling in this manner will avoid putting a reverse bend into the rope as it is being installed. If a rope is installed so that a reverse bend is induced, it may cause the rope to become “cranky” and, consequently, more difficult to work with.

There are several methods, which can be used to uncoil rope from a spool or coil. The particular situation, or application, will determine the method used.

One method begins by placing the coil or spool on a vertical unreeling stand. The stand consists of a base with a fixed vertical shaft. On this shaft there is a “swift” or rotating sleeve” consisting of a plate with inclined pins. This is positioned so that the coil or spool may be placed over them allowing the coil or spool to rotate in the horizontal axis. The whole swift and coil then rotate as the rope is pulled off without adding twist or the possibility of kinks. This method is particularly effective when the rope is to be wound on a vertical drum.

The most common, and the easiest uncoiling method is merely to hold one end of the rope while rolling the coil along the ground like a hoop.

SM141490-EN

7295 Electric Rope Shovel

8 - 39 November 2012

Engineering Data BI011160

NOTE: Avoid unreeling and uncoiling methods that are likely to provide kinks. Such IMPROPER procedures should be strenuously avoided in order to prevent the occurrence of loops.

These loops, when pulled taut, will inevitably result in kinks. No matter how a kink develops, it will damage strands and wires, resulting in a kinked section that must be cut out. Proper and careful handling will keep the wire rope free from kinks.

Improper Methods for Uncoiling Wire Rope

8 - 40 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Seizing Wire Rope While there are numerous ways to cut wire rope, in every case, certain precautions must be observed. It is critical that before any cut is made proper seizings must be applied on both sides of the location where the cut is to be made. Carelessly or inadequately seized, ends may become distorted and flattened. This will also prevent the strands at the ends from loosening or fraying.

Subsequently, when the rope is installed there may be an uneven load distribution to the strands.

This will create a condition that will significantly shorten the life of the rope.

There are two widely accepted methods of applying a seizing, which are illustrated. The seizing material itself should be soft, or an annealed wire or strand. Seizing wire diameter, and the length of the seize, will be dependant on the diameter of the wire rope. But the length of the seize should never be less than the diameter of the rope in use. Normally, for a preformed rope, one seize on each side of the cut is sufficient. For ropes that are not preformed, a minimum of two seizings on each side is recommended; and these should be spaced six rope diameters apart.

For larger wire ropes: lay one end of the seizing wire in the groove between two strands; wrap the other end tightly in a close helix over a position of the groove using a seizing iron (a round bar 1/2" to 5/8" dia. x 18" long) as shown. Both ends of the seizing wire should be twisted together tightly, and the completed seize should appear as shown. Seizing widths should not be less than the rope diameter.

The procedure illustrated below is the second of the two accepted methods for placing seizing on wire rope. This method is normally used on smaller ropes.

SM141490-EN

7295 Electric Rope Shovel

8 - 41 November 2012

Engineering Data BI011160

8 - 42 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

End Preparations/Terminations There may arise a need for special end preparations in order to compensate for certain applications such as tight drum openings, or other complicated reeving systems. When these situations are encountered a number of basic designs (and combinations) are available to choose from. Whenever possible end preparations should be removed after final installation.

“Beckets” are what is referred to when we discuss a termination utilized to pull the operating rope into place. The rope end must be fastened to a mechanism so that force and motion are transferred efficiently without distortion of the wire rope. End terminations become items of great importance for transferring these forces. Each basic type of termination has its own individual characteristic.

Hence, one type will usually fit the needs of a given installation better than others. It should be noted that not all end terminations will develop the full strength of the wire rope being utilized. To lessen the possibility of error, the wire rope industry has determined terminal efficiencies for various types of end terminations. Four commonly used beckets are illustrated.

SM141490-EN

7295 Electric Rope Shovel

8 - 43 November 2012

Engineering Data BI011160

Wire Rope Clips Wire rope clips are widely used for making end terminations. Clips are available in two basic designs; the U-BOLT and FIST GRIP. The efficiency of both types is approximately the same.

NOTE: When using U-BOLT clips, extreme care must be exercised to make certain that they are positioned correctly. The important factor is that the U-BOLT clip be applied in order that the “U” section is in contact with the dead end of the rope. Also, the tightening and re-tightening of the nuts must be accomplished as required.

8 - 44 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Wire Rope Clip Application The following is the recommended method of applying U-Bolt clips in order to get the maximum holding power from the installation: 1.

Turn back the specified amount of rope from the thimble. Apply the first clip a distance of one base width from the dead end of the wire rope (U-bolt over the dead end - live end rests in the clip saddle). Tighten nuts diametrically and evenly to recommended torque.

2.

Apply the next clip as near the loop as possible. Snug down the nuts, but do not tighten.

3.

Space additional clips (if required) equally between the first two. Turn on nuts evenly to take up rope slack. Continue to tighten all nuts evenly (on all clips) until recommended torque is reached.

NOTE: Apply the initial load to the strand of rope, and then re-tighten nuts to the recommended torque. This is accomplished because the rope will stretch and be reduced in diameter when loads are applied. Inspect periodically and tighten to recommended torque each time.

A termination complying with the above instructions, using the number of clips shown, has approximately an 80% efficiency rating. This rating is based upon the nominal strength of the wire rope. If a pulley is used in place of a thimble where the rope turns back, add one additional clip.

The number of clips shown is based upon using right regular or lang lay wire rope, 6 x 19 class or 6 x 37 class, fiber core or IWRC, IPS or EIP. If Seale construction is to be used for sizes 1 inch and larger, or similar large outer wire type construction in the 6 x 19 class, add one additional clip.

The number of clips shown also applies to right regular lay wire rope, 8 x 19 class, fiber core, IPS,

SM141490-EN

7295 Electric Rope Shovel

8 - 45 November 2012

Engineering Data BI011160

sizes 1-1/2 inch and smaller; and right regular lay wire rope, 18 x 7 class, fiber core, IPS or EIP, size 1-3/4 inch and smaller.

For other classes of wire rope not mentioned, it may be necessary to add additional clips to the number shown. If a greater number of clips are used than shown in the table, the amount of rope turn-back should be increased proportionately. THE ABOVE IS BASED ON THE USE OF CLIPS ON A NEW ROPE.

Failure to make a termination in accordance with the aforementioned instructions, or failure to periodically check and re-tighten to recommended torque, will cause a reduction in the efficiency rating.

The correct spacing and number of clips is shown above.

8 - 46 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Wedge Sockets One of the more popular field end attachments for wire rope is the wedge socket. Attachment and the dismantling of this device is both easy and simple.

1.

Inspect the wedge and socket; remove all rough edges/ burrs that might damage the rope.

2.

Welded ends of the rope should be cut off prior to assembly. This will allow the rope strands to distort slightly as they bend sharply around the wedge. If the welded end were not removed the minimal sliding of the strands would be restricted and evidenced further up the rope. This may result in the development of high strands, wavy rope and uneven loading.

3.

Place the socket in an upright position and bring the rope around it in a large, easy to handle loop. Care must be taken to make certain that the live-loaded-side of the rope is in line with the ears.

4.

The dead end of the rope should extend from the socket for a distance of six to nine times the rope diameter. The wedge is now placed in the socket.

5.

Secure the socket and carefully apply a gradually increasing load to the live side of the rope in order to pull the wedge into position. Only tension sufficiently to hold the pieces in place.

SM141490-EN

7295 Electric Rope Shovel

8 - 47 November 2012

Engineering Data BI011160

6.

After checking alignment increase the load GRADUALLY until the wedge is properly seated.

Avoid sudden shock loads.

NOTE: This is the recommended procedure. If variations are made to suit special conditions, they should be carefully evaluated beforehand.

Inspection of Sheaves and Drums Machines should receive periodic inspections, and the results concerning their over-all condition recorded. Such inspections usually include the drum, sheaves, and any other parts that may come into contact with the wire rope. These are considered high wear items. As an additional precaution, any rope-related working parts, particularly those in the areas described below, should be re-inspected prior to the installation of a new wire rope.

Examples of Sheave Groove Conditions

These cross-sections are illustrating three sheave-groove contact areas. “A” is correct, “B” is too tight, and “C” is too loose.

The very first item to be checked when examining sheaves and drums is the condition of the grooves. To accurately check the size, contour and amount of wear, a groove gauge is used. As shown in the figure, the gauge should contact the groove for about 150 degrees of arc when in optimal condition.

There are two types of groove gauges in general use. The two differ by their respective percentage over nominal.

8 - 48 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Groove Gauge for New or Re-Worked Sheaves

For new or re-machined grooves, the groove gauge is nominal plus the full oversize percentage.

The gauge carried by most wire rope representatives today is used for worn grooves and is made nominal plus 1/2 the oversize percentage.

This latter gauge is intended to act as a sort of “no-go” gauge. Any sheave with a groove smaller than this must be re-grooved or, in all likelihood, the existing rope will be damaged.

SM141490-EN

7295 Electric Rope Shovel

8 - 49 November 2012

Engineering Data BI011160

Inspecting for Worn Sheave

These sheave-groove cross-sections represent three wire rope seating conditions: “A” - a new rope in a new groove; “B” - a new rope in a worn groove; and “C” - a worn rope in a worn groove.

Breaking In A New Wire Rope A new wire rope requires careful installation. Adherence to the previously covered procedures is highly recommended. After the rope has been installed, and the ends secured in the applicable manner, the mechanisms should be started carefully and then permitted to run through a complete cycle of operation at greatly reduced speed. During this trial operation, a very close watch should be kept on all working parts such as sheaves, drums and rollers to ensure the rope runs freely. Be vigilant to ensure there are no obstructions as it makes its way through the system. If no problems are apparent, the next step should include several run-throughs of the normal operational cycle under light load conditions at a reduced speed. This procedure allows the component parts of the new rope to gradually adjust to the actual operating conditions.

Inspection Data It is essential to maintain a well-planned program of periodic inspection. Frequently, there are

8 - 50 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

statutory and/or regulatory agencies that incur additional requirements that must be adhered to.

Refer to the suggested procedures that follow.

Abrasion - Bending and crushing represent the ABC’s of wire rope abuse. It is the primary goal of a good inspection practice to uncover such conditions early enough that corrections may be made, or ropes replaced safely with minimum effort. When any sudden degradation indicates a loss of original rope strength, a timely decision is required as to allowing the rope to remain in service.

Such a decision can only be made by an experienced inspector. His/her determination should be based on: 1.

Details of the equipment’s operation.

2.

Frequency of inspection.

3.

Maintenance history.

4.

Consequences of failure.

5.

Historical records of similar equipment.

To ensure sufficient information can be obtained, the following pages contain guidelines that should be adhered to.

Guideline to Inspections and Reports (Equipment, Wire Rope and Wire Rope Slings) 1.

Maintain all inspection records and reports for the length of time deemed appropriate.

2.

Prior to daily use, the following procedure should be followed. a.

Check all equipment functions.

b.

Lower load blocks and check hooks for deformation or cracks.

c. During lowering procedure and the following raising cycle, observe the rope and the reeving. Particular notice should be paid to kinking, twisting or other deformities. Drum winding conditions should also be noted. d. Check wire rope and slings for visual signs of any unsafe condition, including broken wires, excessive wear, kinking or twisting, and severe corrosion. Particular attention should be given to any new damage during operation.

3.

Periodic inspections consistent with applicable standards are recommended with a signed report by an authorized and competent inspector. These Periodic Reports should include inspection of the following: a.

All functional operating mechanisms for excessive wear of components, brake system parts and lubrication.

SM141490-EN

7295 Electric Rope Shovel

8 - 51 November 2012

Engineering Data BI011160

b.

Limit switches.

c.

Crane hooks for excessive throat opening or twisting, along with a visual for cracks.

d.

Wire rope and reeving for conditions causing possible removal.

e. Wire rope slings for excessive wear, broken wires, kinking, twisting and mechanical abuse. f.

All end connections such as hooks, shackles, turnbuckles, plate clamps, sockets, etc. for excessive wear, and distortion.

4.

At least one annual inspection with signed report must be made for the following: a.

Crane hook for cracks.

b.

Hoist drum for wear or cracks.

c.

Structural members for cracks, corrosion and distortion.

d.

For loose structural connections such as bolts, rivets, and weldments.

8 - 52 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Wire Rope Inspection Criteria The following is a fairly comprehensive listing of critical inspection factors. It is not, however, presented as a substitute for an experienced inspector. It is rather a user’s guide to the accepted standards by which ropes must be judged.

Abrasion Rope abrades when it moves through an abrasive medium or over drums and sheaves. Most standards require that rope is to be removed if the outer wire wear exceeds 1/3 of the original outer wire diameter. This is not easy to determine and discovery relies upon the experience gained by the inspector in measuring wire diameters of discarded ropes.

Reduction in Rope Diameter: Any marked reduction in rope diameter indicates degradation. Such reduction may be attributed to: •

Excessive external abrasion.

•

Internal or external corrosion.

•

Loosening or tightening of rope lay.

•

Inner wire breakage.

•

Ironing or milking of strands.

In the past, the determination on the continued service of a rope was largely dependent on the rope’s diameter at the time of inspection. Recently this practice has undergone significant modification.

Previously, a decrease in the rope’s diameter was compared with published standards of minimum diameters. The amount of change in diameter is, of course, useful in assessing a rope’s condition.

But, comparing this figure with a fixed set of values can be misleading. These long-accepted minimums are not, in themselves, of any serious significance since they do not take into account such factors as: •

Variations in compressibility between IWRC and Fiber Core.

• Differences in the amount of reduction in diameter from abrasive wear, or from core compression, or a combination of both.

•

The actual original diameter of the rope rather than its nominal value.

As a matter of fact, all ropes will show a significant reduction in diameter when a load is applied.

Therefore, a rope manufactured close to its nominal size may, when it is subjected to loading, be reduced to a smaller diameter that stipulated in the minimum diameter table. Yet, under these circumstances, the rope would be declared unsafe although it may, in actuality, be safe.

SM141490-EN

7295 Electric Rope Shovel

8 - 53 November 2012

Engineering Data BI011160

As an example of the possible error at the other extreme, we can take the case of a rope manufactured near the upper limits of allowable size. If the diameter has reached a reduction to nominal or slightly below that, the tables would show this rope to be safe. But it should, perhaps, be removed.

Evaluations of the rope diameter are first predicated on a comparison of the original diameter when NEW and subjected to a KNOWN load with the current reading under comparable circumstances.

Periodically, throughout the life of the rope, the actual diameter should be recorded while the rope is under equivalent loading and in the same operation section. This procedure, if followed carefully, reveals a common rope characteristic: after an initial reduction, the diameter soon stabilizes. Later, there will be a continuous, albeit small, decrease in diameter throughout its life.

Core deterioration, when it occurs, is revealed by a more rapid reduction in diameter and is time for removal.

Deciding whether or not a rope is safe is not always a simple matter. A number of different but interrelated conditions must be evaluated. It would be dangerously unwise for an inspector to declare a rope safe for continued service simply because its diameter had not reached the minimum arbitrarily established in a table, while at the same time, other observations lead to an opposite conclusion.

Because criteria for removal are varied, and because diameter in itself, is a vague criterion, the table of minimum diameters has been deliberately omitted from this publication.

Rope Stretch All ropes will stretch when loads are initially applied.

8 - 54 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Wire Rope Stretch vs. Rope Life

As a rope degrades from wear, fatigue, etc., (excluding accidental damage), continued application of a load of constant magnitude will produce varying amounts of rope stretch. A “stretch” curve plotted for stretch vs. time displays three distinct phases: PHASE 1. - Initial stretch, during the early (beginning) period of rope service, caused by the rope adjustments to operating conditions (constructional stretch).

PHASE 2. - Following break-in, there is a long period-the greatest part of the rope’s service lifeduring which a slight increase in stretch will take place over an extended time. This results from normal wear, fatigue, etc. On the plotted curve stretch vs. time-this portion would almost be a horizontal straight line inclined slightly upward from its initial level.

PHASE 3. - Thereafter, the stretch occurs at a quicker rate. This means that the rope has reached the point of rapid degradation, a result of prolonged subjection to abrasive wear, fatigue, etc. This second upturn of the curve is a warning indicating that the rope should soon be removed.

Corrosion Corrosion, while difficult to evaluate, is a more serious cause of degradation than abrasion. Usually, it signifies a lack of lubrication. Corrosion will often occur internally before there is any visible external evidence on the rope surface. Pitting of wires is a cause for immediate rope removal. Not only does it attack the metal wires, but also prevents the rope’s component parts from moving smoothly as it is flexed. Usually, a slight discoloration because of rust merely indicates a need for lubrication.

SM141490-EN

7295 Electric Rope Shovel

8 - 55 November 2012

Engineering Data BI011160

Severe rusting, on the other hand, leads to premature fatigue failures in the wires necessitating the rope’s immediate removal from service. When a rope shows more than one wire failure adjacent to a terminal fitting, it should be removed immediately. To retard corrosive deterioration, the rope should be kept well lubricated. In situations where extreme corrosive action can occur, it may be necessary to use galvanized wire rope.

Kinks Kinks are permanent distortions caused by loops drawn too tightly. Ropes with kinks must be removed from service.

Bird Caging Bird caging results from torsional imbalance that comes about due to mistreatment such as sudden stops, rope being pulled through excessively tight sheaves, or wound on too small a drum for a given rope diameter. This is cause for rope replacement unless the affected section can be removed.

Localized Conditions Careful attention must be paid to wear at the equalizing sheaves. During normal operation this wear is not visible. Excessive vibration, or whip can cause abrasion and/or fatigue. Drum crossover and flange point areas must be carefully evaluated. All end fittings, to include splices, should be examined for worn or broken wires, loose or damaged strands, cracked fittings and worn or distorted thimbles and tucks of strands.

Heat Damage After a fire, or exposure to elevated temperatures, there may be discoloration, or an apparent loss of internal lubrication. Fiber core ropes are particularly vulnerable. Under these circumstances the rope should be replaced.

Protruding Core If, for any cause, the rope core protrudes from an opening between the strands, the rope is unfit for service and should be removed.

Damaged End Attachments Cracked, bent, or broken end fittings must be eliminated. The cause should be sought out and corrected. In the case of bent hooks, the throat openings must be measured at the narrowest point and should not exceed 15% over normal. Twisting to be no greater than 10 degrees.

8 - 56 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Peening Continuous pounding is one of the causing of peening. The rope can strike against an object, such as some structural part of the machine, or it beats against a roller, or itself. Often this can be avoided by placing protectors between the rope and the object it is striking. Another common cause of peening is continuous working under high loads over a sheave or drum. Where peening action cannot be controlled it is necessary to have more frequent inspections and be prepared for premature rope replacement.

Scrubbing Scrubbing refers to the displacement of wires and strands as a result of rubbing against itself or another object. This, in turn, causes wear and displacement of wires and strands along one side of the rope. Corrective measures should be taken as soon as this condition is observed.

Fatigue Fracture Wires that break with square ends and show little surface wear have usually failed as a result of fatigue. Such fractures can occur on the crown of the strands, or in the valleys between the strands where adjacent strand contact exists. In almost all cases, these failures are related to bending stresses or vibration.

If diameter of the sheaves, rollers or drum cannot be increased, a more flexible rope should be used. But, if the rope in use is already of maximum flexibility, the only remaining course that will help prolong its service life is to move the rope through the system by cutting off the dead end. By moving the rope through the system, the fatigued sections are moved to less fatiguing areas of the reeving.

Broken Wires The number of broken wires on the outside of a wire rope are an index of 1) its general condition, and 2) whether or not it must be considered for replacement. Frequent inspection will help determine the elapsed time between breaks.

SM141490-EN

7295 Electric Rope Shovel

8 - 57 November 2012

Engineering Data BI011160

On occasion, a single wire will break shortly after installation. However, if no other wires break at that time, there is no need for concern. On the other hand, should more wires break, the cause should be immediately investigated.

On any application, valley breaks (where the wire fractures between strands) should be given serious attention. When two or more such fractures are found, the rope should be replaced immediately.

NOTE: No valley breaks are permitted in elevator ropes.

Once broken wires appear within a rope operating under normal conditions many more will show up within a relatively short period. Attempting to squeeze the last measure of service from a rope that is beyond the allowable number of broken wires will create an intolerably hazardous situation.

Examples of Broken Wires

A wire broken under a tensile load that has exceeded its strength is recognized by the “cup and cone” configuration at the fracture point (Rope A). The necking down of the wire at this point shows that failure occurred while the wire retained its ductility. Shear-tensile fracture (Rope B) occurs in wire subjected to a combination of transverse and axial loads. Fatigue breaks are usually characterized by squared-off ends perpendicular to the wire either straight across or Z-shaped (Ropes C and D).

Electric Arc Rope that has either been in contact with a live power line or been used as “ground” in an electric welding circuit, will have wires that are fused, discolored and/or annealed, and must be removed.

8 - 58 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Seals Oil and grease seals are critical to machine availability. Careless storage, handling, removal and installation can contribute to reduced service life of machine components and higher cost of operation.

Seals come in all sizes, shapes and materials. Wherever possible, the manufacturer has specified the use of the most common solid molded element type seals for use on electric rope shovels.

All types of oil and grease seals have a limited shelf life. Store seals in a cool, dry location protected from direct sunlight. Keep in sealed containers or packaging until ready to use. Seals keep lubricant clean and contained in their respective housings, bearings or passageways. Always handle seals carefully to prevent exposure to nicks, bends or pinching. Do not wash them in solvents as some solvents may destroy properties of the seal.

Seal Installation Solid molded seals are installed at time of manufacture with interference fit between seal and bore.

This method of installation creates an oil tight fit. When partial disassembly of a machine component involves removal of solid molded seal before reassembly inspect it carefully for cuts, nicks or cracking. Replace with a split seal if complete disassembly is inconvenient or with a new solid molded seal. Split seals, especially those made with interference fit at butt, also install with compression at the joint. Split seals used as substitutes for solid molded seals should be replaced at next major component overhaul.

Do not cut a solid seal and reuse for a split seal.

Check shaft for scratches, burrs or surface roughness that may cut or score the lip of seal. Be aware of sharp threads keyways or splines over which the seal must travel. Protect seal lip by covering these interferences with tape.

Inspect the bore area for surface roughness, dirt or burrs. Remove and clean as required. The bore and shaft need .0625 in. (1.588 mm) chamfer to accommodate a leak free installation. If shaft or bore do not have chamfer, carefully provide one by trimming inside flange of seal.

Determine the correct direction for lip installation and start the seal into the cavity by finger pressure, then tap evenly all around until seated or flush with the housing face. (Tap only on outer edge of seal with hammer on wood block.)

A double seal, installed back to back can be used to retain grease or oil plus be more effective in preventing egress of contaminants.

SM141490-EN

7295 Electric Rope Shovel

8 - 59 November 2012

Engineering Data BI011160

Split Seal Installation

Follow this installation procedure for split seals: •

Remove garter spring and separate at the hook and eye.

•

Open the seal, ends sideways, for installation on shaft as shown by moving the butt ends along the axis of the seal.

•

Lubricate spring and install around shaft. Connect ends and insert spring in lip groove with spring ends 90o away from butt joint.

Do not trim or cut ends of split seals or pull ends apart. This will destroy seal.

Gearcase seals used for all oil tight gearcase assemblies require surface preparation on one side of case flanges with a 1/100 inch thick Form-a-Gasket #3 (Permatex Co.) coating. If using a manila paper gasket always replace with a new one, never reuse. Apply Form-a-Gasket #3 to both sides of the paper gasket. Tighten gearcase cover bolts until seal material “squeezes out” at joint.

When surface finishes range up to 250 micro-inches, a compression type gasket seal is recommended. This material (VELLUMOID) available in standard thickness inches (mm) 1/64 (.397), 1/32 (.794), 1/16 (.063), and 1/8 (.125) should also be installed with Permatex applied to both sides.

8 - 60 November 2012

7295 Electric Rope Shovel

SM141490-EN

Engineering Data BI011160

Gearcase Sealing Use the information in the following image to properly seal gearcase halves and /or covers.

NOTE:

Before applying any sealants or gaskets, clean all mating surfaces of all dirt, rust and scale.

SM141490-EN

7295 Electric Rope Shovel

8 - 61 November 2012

Engineering Data BI011160

8 - 62 November 2012

7295 Electric Rope Shovel

SM141490-EN