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| Illustration 1 | g01060582 |
Hydraulic system for the fan and for the coupler (1) Coupler cylinder (2) Solenoid valve (coupler) (3) Solenoid valve (coupler) (4) Gear pump (5) Fan drive motor (6) Hydraulic tank (A) Supply line to bank valve (B) Line to the hydrostatic pump case | |
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| Illustration 2 | g01060621 |
(7) Switch for the solenoid valves | |
The hydraulic system for the coupler is controlled by a switch (7) in the cab of the machine. The switch controls the solenoid valves (2) and (3).
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| Illustration 3 | g01060626 |
Typical gear pump (3) Solenoid valve (coupler) (4) Gear pump | |
The rear section of the gear pump (4) supplies oil to the system. When the switch in the cab (7) is not activated, the solenoid valves (2) and (3) are in the positions that are shown in illustration 1. The supply oil from the gear pump flows to both the fan drive motor (5) and to the coupler cylinders (1). The cylinder rods extend and the rods engage the coupler pins into the work tool. This secures the work tool to the machine. The cylinders will remain extended by hydraulic pressure. Once the cylinders are completely extended all of the oil from the rear section of the gear pump will flow to the fan drive motor.
The supply oil causes the fan drive motor to turn. Then, the oil flows to the tank (6). The pressure of the system is limited by the relief valve in the fan drive motor (5). The excess oil that passes through the relief valve flows to the tank (6).
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| Illustration 4 | g01060629 |
Hydraulic system for the fan and for the coupler (1) Coupler cylinder (2) Solenoid valve (coupler) (3) Solenoid valve (coupler) (4) Gear pump (5) Fan drive motor (6) Hydraulic tank (A) Supply line to bank valve (B) Line to the hydrostatic pump case | |
When the switch (7) in the cab is activated, the two solenoid valves (2) and (3) shift to the positions that are shown in illustration 4. Supply oil from the gear pump flows only to the valve (2). The valve (2) directs the oil flow to the rod ends of the coupler cylinders (1) in order to retract the cylinders. When the cylinders retract, the coupler pins are pulled out of the work tool and the work tool can then be removed.
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| Illustration 5 | g01060642 |
(1) Coupler cylinder (8) Pilot controlled check valve (9) Thermal pressure relief valve | |
The coupler cylinders (1) contain pilot controlled check valves (8) that allow the cylinder rods to be retracted when the lines are pressurized. When the supply oil is flowing to the rod end of the cylinders the pilot line of the pilot operated check valve is charged. This shifts the check valve in order to allow the oil from the head end of the cylinders to flow to the tank. If the engine fails or a line brakes the coupler pins cannot disengage because the pilot line of the pilot operated check valve is not charged. The check valve cannot shift. This prevents oil from flowing from the head end of the cylinder through the check valve and to the tank.
The thermal pressure relief valve (9) releases excess pressure in the cylinder that is due to high temperatures of the oil.