 | |
| Illustration 1 | g01898315 |
 | |
| Illustration 2 | g01898316 |
Load Sensing Signal System for 584 Forwarder (1) Implement control valve (2) Resolvers (load sensing) (check valve) (3) Accumulator (brake) (rear) (4) Manifold (rear brake and differential lock) (5) Valve (steering and blade) (6) Hydraulic oil tank (7) Manifold (front brake and differential lock) (8) Piston pump (power train) (9) Accumulator (brake) (front) (10) Valve (load sensing dump) (pilot) (11) Pressure tap (implement piston pump) (supply pressure) (12) Valve (standby pressure) (13) Valve (high pressure cutoff) (14) Piston pump (implement) | |
When a function is activated or deactivated, the output of the implement pump must change in order to match the required flow and the required pressure. The load sensing signal system controls the output of the pump.
The load sensing signal system is composed of the following components:
- Piston pump (implement)
- Implement control valve
- Steering valve
- Brake and differential lock valve (front)
- Brake and differential lock valve (rear)
- Pressure relief valve (maximum signal pressure)
- Pressure relief valve (steering signal pressure)
 | |
| Illustration 3 | g01899094 |
(15) Pilot button | |
When the engine starts, there is no pressure in the load sensing signal system. This will assist the starting of the engine by decreasing the load on the engine.
Note: The hydraulic system and the brake system are not active until the pilot button (15) is depressed. The pilot button will turn red in order to indicate that the hydraulic system is active. The normal color of the light is yellow. When the pilot button is in the off position the parking brake will apply and the ladder will lower.
When the operator pushes the pilot button, electrical current flows to load sensing valve (10). The load sensing valve allows signal pressure oil to flow to the piston pump (14) .
The piston pump (implement) (14) is at maximum output. As the piston pump begins to pump, the pressure in the signal system increases. This will also charge accumulators (3) and (9). The pump strokes to low pressure standby until a function is activated.
If a function that is controlled by implement control valve (1) is activated, the function will send another load signal into the load sensing system.
A resolver network (2) in the implement control valve (1) allows the highest signal pressure in the implement control valve to flow to a resolver. The resolver allows the higher signal pressure from the implement control valve to be sensed by the pump.
The load signal from implement control valve (1) then flows to valve (12). Valve (12) limits the maximum pressure of the load signal from the hydraulic system to piston pump (14). Therefore, pressure relief valve (13) limits the high pressure of piston pump for the hydraulic system.
Note: The pressure setting of pressure relief valve (12) is below the pressure setting of the pressure cutoff valve (13) in piston pump.
Note: The switch for the engine must be in the ON position in order to lower the boom when the engine is stopped.