Pilot Operated Machines
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| Illustration 1 | g01213419 |
(1) Joystick for the loader (2) Pilot lines from the joystick (3) Return Line (4) Supply line (5) Return manifold (6) Accumulator (7) Pressure reducing valve (8) Pump oil (9) Joystick for the backhoe (10) Joystick for the backhoe (11) Control valve for the pilot shutoff | |
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| Illustration 2 | g01213425 |
The lock valve is located on the inside of the frame by the left rear tire. (11) Lock valve and (12) Rear axle | |
Note: The pilot lock valve (11) is only on the machines with pilot operated controls.
Oil from the pump enters the pressure reducing valve (8) through line (8). Oil from the pressure reducing valve flows to the accumulator (6) and pilot lock valve (11). When the machine is off or the switch for the pilot lock valve is engaged, the power is blocked to the solenoid. Then, the valve spring is applied. In the lock position, the pilot lock valve blocks the pilot oil to the joysticks. In the unlock position, power is sent to the solenoid on the pilot lock valve. This allows oil to flow to the joysticks through line (4). Pilot lines (2) from the joysticks control the bank valves for the loader and the backhoe.
Accumulator (6) remains pressurized after the engine is turned off. This allows the operator to use the joysticks to lower the equipment with the engine stopped.
Note: The pressure in the accumulator will only last for a short period of time. The ignition switch must be in the on position before the pilot lock valve can be deactivated.
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| Illustration 3 | g00832869 |
Hydraulic lock switch | |
The solenoid for the pilot shutoff is de-energized when the top of the switch is pressed. When the solenoid for the pilot shutoff is de-energized, the pilot operated controls for the loader and for the backhoe are deactivated and no movement of the machine can be made by using the pilot operated controls. The pilot shutoff does not affect the operation of the stabilizers.
The solenoid for the pilot shutoff is energized by pressing the bottom of the switch. When the solenoid for the pilot shutoff is energized, the pilot operated controls for the loader and for the backhoe are activated. Movement of the machine can be made by using the pilot operated controls.
Mechanically Operated Machines (If equipped)
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| Illustration 4 | g01127024 |
(1) Line to signal resolver network (2) End cover for the bank valve (3) Hydraulic lockout valve (4) Auxiliary control valve (5) Hydraulic tank return passage (6) Line from the signal resolver in the boom control valve (7) Pump supply passage (8) Pump supply inlet (9) Flow control valve | |
Note: The hydraulic lockout valve is only on the machines with mechanically operated backhoe controls.
Oil from the hydraulic pump enters pump supply line (8) and flows to the flow control valve (9) in the end cover for the bank valve (2). When the pump supply pressure overcomes the force of the spring in the flow control valve, flow control valve (9) shifts in order to allow the pump supply oil to flow into the bank valves for the backhoe. The pump supply oil flows into the pump supply passage (7). Pump supply passage (7) is common to all of the valves in the bank valve for the backhoe.
The hydraulic oil that is used by the backhoe control valves is returned to the hydraulic tank through the hydraulic tank return passage (5) .
Hydraulic lockout valve (3) is mounted on the end cover for the bank valve (2). The end cover for the bank valve is mounted to the auxiliary control valve (4). When the solenoid for the hydraulic lockout valve is energized, hydraulic lockout valve (3) shifts. When hydraulic lockout valve (3) shifts, the pilot oil that shifted the flow control valve is vented to the tank and the spring in flow control valve (9) shifts the flow control valve. When flow control valve (9) shifts, pump supply oil is again blocked from entering the bank valves. When the pump supply oil is blocked from entering the bank valves, none of the backhoe control levers will activate the hydraulic circuits for the backhoe.