The hydraulic control console must be activated in order for the pilot valves (joysticks) to function.
When the left pilot valve (joystick) is moved forward, the stick will move out. When the left pilot valve (joystick) is moved backward, the stick will move in. The pilot valve (joystick) will return to the HOLD position when the pilot valve (joystick) is released from either position.
ReferenceRefer toOperation and Maintenance Manual, "Joystick Controls" for more information on the operation of the pilot valves (joysticks).
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| Illustration 1 | g01279843 |
Partial hydraulic schematic (1) Stick cylinder (2) Stick control valve (3) Main control valve (4) Pilot control valve (Swing and Stick) (5) Oil line for stick out operation (6) Oil line for stick in operation (7) Main pump (8) Hydraulic line (9) Pilot manifold | |
Stick In
When the pilot valve (joystick) is moved backward, pilot oil (5) shifts the spool of the stick control valve (2). Oil is routed from the pump (7) to the main control valve (3). The pump receives oil from the hydraulic tank through the hydraulic line (8). The oil from the main pump flows through the stick control valve to the head end of the stick cylinder (1). This causes the cylinder rod to extend. The extending of the stick cylinder rod causes the stick to move in.
Stick Out
When the pilot valve (joystick) is moved forward, pilot oil (6) shifts the spool of the stick control valve (2) in the opposite direction. Oil is routed from the pump (7) to the main control valve (3). The pump receives oil from the hydraulic tank through the hydraulic line (8). The oil from the main pump flows through the stick control valve to the rod end of the stick cylinder (1). This causes the cylinder rod to retract. The retracting of the stick cylinder rod causes the stick to move out.
Refer to the Systems Operation, "Main Control Valve" for more information on the main control valve and the stick control valve.