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| Illustration 1 | g00475228 |
Load sense manifold (1) Manifold (2) Shuttle valve (3) Three-way pilot control valve (4) Shuttle valve (5) Shuttle valve (6) Shuttle valve (a1) HOOK LOWER port (pilot pressure) (b1) HOOK RAISE port (pilot pressure) (A1) HOOK LOWER pressure port (B1) HOOK RAISE pressure port (A2) BOOM LOWER pressure port (B2) BOOM RAISE pressure port (LS) Load sensing port (DR) Drain port | |
The load sense manifold is used in order to resolve the highest pressure that is required by either the boom or the hook winch. This pressure signal is sent to the load sensing port on the piston pump. The pump responds with the proper pressure in order to perform the task.
When the boom is being lowered or raised, a load sensing signal from the motor ports on the winch motor for the boom enters either port (A2) or (B2) . This pressure shifts shuttle valve (4) and the oil travels to shuttle valve (5) . The pressure shifts shuttle valve (5) to the right and the oil exits through port (LS) . This oil travels to the piston pump and the pump adjusts the output in order to fit the pressure that is required.
See Hydraulic Systems Operation, "Hydraulic Pump" for more information.
See Hydraulic Systems Operation, "Shuttle Valve" for more information.
If the hook is being lowered or raised, a pilot pressure enters either port (a1) or (b1) . This pilot pressure is from the pilot control valve for the hook winch. The pilot signal travels to shuttle valve (2) and the valve shifts in order to allow the oil to pass. This oil travels to three-way pilot control valve (3) and the pressure shifts this valve to the right. This opens a path for the load sensing pressure for the hook to travel to the piston pump.
See Hydraulic Systems Operation, "Three-way Pilot Control Valve" for more information.
The load sensing signal from the motor ports on the hook winch enters either port (A1) or (B1) . The oil travels to shuttle valve (6) and the valve shifts in order to allow oil to pass. This oil travels to three-way pilot control valve (3) . Since the pressure from ports (a1) and (b1) have opened valve (3) , the load sensing signal from shuttle valve (6) is allowed to pass. This oil travels to shuttle valve (5) and valve (5) shifts in order to allow the signal to pass. This signal exits through port (LS) and the pressure travels to the piston pump. The pump adjusts the output in order to fit the pressure that is required.
When the pressure is removed from ports (a1) and (b1) , valve (3) shifts to the left and the oil on the right side of valve (5) is allowed to drain through port (DR) .
If the hook and the boom are being operated at the same time, shuttle valve (5) shifts in order to allow the highest pressure to exit through port (LS) .