Propel - Straight Forward/Reverse

PROPEL MOTION

Propel motion is controlled by placing the propel transfer switch in the propel mode and actuating the left or right joystick. To propel in a straight forward direction, push forward on both the left and right joysticks at the same time. The speed is increased as the levers are displaced farther from neutral. To propel straight in reverse, pull equally both joysticks to the rear.

NOTE: The control stop pushbutton must be pressed before the propel transfer switch can be activated.

DANGER: THE HOIST BRAKE MUST BE SET WHENEVER IN THE PROPEL MODE.

Propel - Straight Forward/Reverse

SWING MOTION

In standard configuration, Swing motion is controlled by the operator’s right joystick. To swing in either direction, move the joystick lever in the direction of swing. Practice swinging in each direction until a “feel” is developed for start-up and stopping.

NOTE: The joy stick also controls the hoisting and lowering of the dipper through forward and backward motions.

DANGER: Each motion - hoist or swing - is fully operational throughout the complete movement of the other motion.

NOTE: When this joystick is used for propelling the machine, the hoist and swing motions are electrically locked out.

NOTE: The following represents the standard configuration.

PROPER SWING MOTION

Proper swing motion means smooth control and an efficient swing cycle. The swing motion is begun toward the haulage unit when the dipper is filled and is clear of the bank.

DANGER: EXTENSIVE DAMAGE TO THE DIPPER HANDLE AND DIPPER CAN OCCUR IF THE MACHINE IS ROTATED BEFORE THE DIPPER CLEARS THE BANK.

The swing motion begins with acceleration to an optimum point at which the excavator is brought to a stop over the haulage unit. Maximum efficiency and minimum swing machinery wear are direct results of mastering the swing motion.

NOTE: Improper swing motion results in erratic control and an inefficient swing cycle.

DANGER: THE DIPPER SHOULD NEVER BE POSITIONED OVER PERSONNEL, TRAIL CABLES, RELATED ELECTRICAL EQUIPMENT OR OTHER EQUIPMENT. When the dipper is loaded, accidental tripping of the dipper door could result in death or serious injury to personnel and extensive damage to equipment. Empty dippers may contain small fragments of material that can be extremely dangerous when dropped from a considerable height. On long moves open the door on an empty dipper and lower the dipper to a point that permits moving without striking the ground.

Time is required to accelerate any motion from zero to working speed and also to decelerate from working speed back to zero. THE TIME EXPENDED FOR ACCELERATING AND DECELERATING THE SWING REPRESENTS THE MAJOR PART OF THE ENTIRE DIG CYCLE. Therefore, the swing arcs must be kept to a minimum to obtain maximum operating efficiency. As an example: assuming that a 90° swing results in 100 percent of the maximum output, increasing the swing arc to 180° reduces output to 70 percent, while decreasing the swing arc to 45° increased the output to 126 percent. Therefore, a swing arc of 90° or less should usually be used.

Haul units should be positioned so their center line is approximately under or not more than slightly outside the swing path of the boom point. This substantially reduces the amount of dipper maneuvering required of the operator when positioning the dipper for dumping. Positioning of the haulage unit inside or outside the boom point makes it necessary to retract or crowd the dipper handle and dipper, which breaks the operator’s natural rhythm.

A clean, level pit floor must be maintained. A good operator will always clean the floor before moving into the bank. A clean and level floor grade is a requisite to safe and stable machine operation and reduces damage to crawler links and related components.

DANGER: “SWEEPING” SHOULD NEVER BE ATTEMPTED WITH THE MACHINE. Sweeping consists of lowering the dipper to the ground and using the swing motion of the machine to move the dipper from side-to-side and “sweep” the pit floor. THE DIPPER, DIPPER HANDLE AND BOOM STRUCTURES CAN BE DAMAGED BY SWEEPING. A bulldozer or loader should be used to help the machine operator maintain a clean pit floor in conjunction with the shovel.

STEERING

To make a gradual forward right turn, move the LEFT joystick (crowd) forward and leave the right joystick (hoist) in neutral.

To make a gradual forward left turn, move the RIGHT joystick (hoist) forward and leave the left joystick (crowd) in neutral.

Whenever possible, gradual turns should be made in short increments of 15° to 20° maximum. Propel straight for a short distance (usually 1/2 the length of the crawler belts) to clear the crawler belts of stone and other debris; then make another 15° to 20° turn. Continue until the turn is completed.

NOTE: When steering in soft material such as sand, clay, etc., increments of less than 15° to 20° should be used to minimize material build up on the crawler belt roller path.

COUNTER-ROTATION TURNS

Although possible, a single sharp turn should be avoided to minimize material build up on the crawler belt roller path. This results in high loading of the crawler belt and associated propel components.

To make a sharp right turn, move the LEFT joystick forward and pull the RIGHT joystick to the rear.

To make a sharp left turn, move the RIGHT joystick forward and pull the LEFT joystick to the rear.

CAUTION: When using the counter-rotation method for turning, have a helper ensure that the trail cable does not get fouled and/or torn from the machine.

NOTE: The ability of the machine to turn sharply is dependent on the surface on which the machine is setting. A soft surface will cause the crawlers to dig-in and machine to bogdown.

CAUTION: The propel brakes are released when either joystick is moved from neutral. The propel brakes are set when both joysticks are returned to neutral.

When moving the machine in a straight line, propel forward, which is in the direction of the take-up axle to reduce strain on the crawler belts and propel mechanism. When not possible and propelling to the rear, make sure the trail cable is clear of the machine and follow the signals given by the helper. The machine should be rotated in a position to allow the operator to face the direction of travel.

NOTE: Turning when propelling to the rear requires that the master control be positioned in a direction opposite the actual direction in which the turn takes place.

The machine should be moved close to the bank in short and frequent moves to maintain digging efficiency. Movement should occur between the loadings of haul units.

POSITIONING THE MACHINE

There are two basic methods for positioning the machine at the working face of the bank: the “back-up method” and the “drive-by method”. Both methods are acceptable and effective.

BACK-UP METHOD

When using the back-up method, position the machine at the bank with the front of the machine facing the digging face. The haul units are spotted on both sides of the machine. The bank can be excavated until a 180° circular area of material has been removed from the bank. Once the material is removed, a 90° or greater swing will be required in order to load the haul units, requiring the machine to be moved.

To reposition the machine, propel to the rear, away from the bank, at an approximate 45° angle to the bank. When the machine is centered in-line with the untouched edge of the previous excavation, propel straight toward the bank and position the machine for further digging.

The back-up method will minimize the swing arc and reduce moving time, produce less bank toe area clean up and simplify handling of the trail cable, cable standard and trail cable boat.

DRIVE-BY METHOD

NOTE: If mine conditions or equipment prevent the use of the following procedures, use the “Back-up Method” instead.

Position the machine crawlers parallel to the bank with the outer set of crawler tracks directly in line with the bank toe.

The haul units must approach the machine from the front, making a turn away from the machine as the unit’s front wheel approaches the outside crawler. Haul units then stop in a position to allow backing toward the point of the bank for loading. During the load cycle, swing arc is to one side only and should not exceed 90°. The cycle time from one full haul unit to the next empty unit should not exceed the cycle time between successive dipper loads to each unit.

During the load cycle, the swing arc should not exceed 90°. The time between finishing one truck to the first digging cycle of the next should not exceed that of any cycle during a load.