SWING MOTOR GP-MOUNTING & 0874823 - Caterpillar

Illustration 1 g00564294
Travel pilot control valve (1) Control pedal (2) Pedal (3) Rod (4) Seat (5) Spring (6) Spring (7) Spool (8) Passage (9) Passage (10) Spring (11) Spool (12) Return port (13) Return chamber (14) Passage (15) Passage (16) Pilot port (17) Passage (18) Port (19) Passage (20) Passage (21) Passage (22) Port
Illustration 2 g00564539
(23) Travel pilot control valveWhen control pedal (1) is moved to the FORWARD TRAVEL position, pedal (2) pushes down on rod (3). Pedal (2) also pushes seat (4) against the force of springs (5) and (6). Spool (7) moves down in order to open passage (19) by compressing spring (6) .As passage (19) is opened, the oil from pilot port (16) goes through passages (21), (19), (20) and (9), and out port (18) to the travel control valve. The pressure on the end of the travel control valve stem causes the travel control valve stem to move into the forward position.The oil from the chamber at the opposite end of the main control valve for travel comes back through port (22) and through passages (17), (15) and (14). The oil now flows into return chamber (13) and back to the hydraulic tank through return port (12) .When control pedal (1) is partially moved for fine travel operation, rod (3) moves down with seat (4). This causes spring (6) to shift spool (7) downward. Passage (19) opens and the oil pressure increases at port (18). Since the oil pressure is more than the force of spring (6), spool (7) moves up in order to open passage (8). The oil from port (18) goes through passages (9), (20) and (8) into return chamber (13). The oil pressure slightly decreases. Spool (7) is now held in a pressure modulating position in order to establish a balance between the pressure in port (18) and the force of spring (6) .When the control pedal is released, spring (5) pushes up on seat (4) and rod (3). The pedal returns the lever to the NEUTRAL position. The spool moves up. The oil in port (18) can now flow through passages (9), (20), and (8) through return chamber (13) and back to the hydraulic tank.When control pedal (1) is moved to the REVERSE TRAVEL position, the operation is identical to the forward travel position that was previously described.Travel Lock
Illustration 3 g00564545
(1) Travel lock (magnet)With the travel lock, it is possible to travel at high speed when the travel pedal has been released. This function should only be used for normal forward movement.Travel lock (1) is a magnet. The energized magnet retains the fully depressed travel pedal. The indicator in the switch is illuminated when the travel lock is activated. Maximum travel speed will be maintained until the operator performs one of the following steps:
Push down on the front of the travel lock switch.
Push down on the wheel brake pedal.
Push down on the travel speed pedal.Refer to Operation and Maintenance Manual, "Travel Lock Control".