Grapple Open/Close Operation
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| Illustration 1 | g01416385 |
(1) Proportional valve (2) Passage (3) Passage (4) Passage (5) Passage (6) Line (7) Main control valve (left) (8) Passage (9) Parallel feeder passage (10) Passage (11) Passage (12) Line (13) Proportional valve (14) Return line (15) Line (16) Line (17) Line (PS pressure to front and rear pumps) (18) Grapple cylinders (19) Pilot oil filter (20) Passage (21) Pilot line (22) Solenoid valve (hydraulic activation) (23) Line (24) Proportional reducing valve (PS pressure) (25) Passage (26) Rear pump (27) Valve (hydraulic activation) (28) Pilot line (29) Passage (30) Hydraulic tank (31) Pilot pump (32) Attachment valve (33) Flow compensator valve (34) Check valve (35) Passage (36) Passage (37) Passage (38) Passage (39) High pressure filter (option) (40) Front pump | |
The oil delivery for the open/close operation is supplied by the front pump (40) and the rear pump (26) .
The oil delivery from front pump (40) and rear pump (26) flows through lines (12) and parallel feeder passage (9) in main control valve (7) to grapple control valve (32) .
When the hydraulic activation control lever is in the UNLOCKED position, the oil delivery from pilot pump (22) flows through line (23) to pilot oil filter (19). The oil flows from the pilot oil filter through line (28) to the pilot oil manifold. The pilot oil flows through passage (25) to solenoid valve (22). The pilot oil flows from solenoid valve (22) through passage (20) to valve (27). The pilot oil flows from valve (27) through line (21), passage (2) and passage (5) to proportional solenoid valves (13) and (1).
Pilot oil from proportional solenoid valve (1) flows through passage (8) to grapple control valve (32). At the same time, pilot oil from proportional solenoid valve (13) flows through passage (11) to grapple control valve (32). Since the pressure of the pilot oil in passage (8) is equal to the pressure of the pilot oil in passage (11), the grapple control valve remains in the NEUTRAL position.
When the slider on the right joystick is moved downward to the GRAPPLE OPEN position, proportional solenoid valve (13) is energized and the valve begins to shift upward. Pilot oil in passage (11) flows through proportional solenoid valve (13) to passage (4). The oil flows from passage (4) through line (14) back to hydraulic tank (30). Since the pressure of the pilot oil in passage (11) is less than the pressure of the pilot oil in passage (8), grapple control valve (32) shifts downward.
Proportional reducing valve (24) is energized when the slider on the right joystick is moved upward. Pilot oil in passage (29) supplies pilot oil to proportional reducing valve (24). The machine ECM controls proportional reducing valve (24) in order to control the negative flow control pressure to the front and rear pumps. The output flow rate of the pumps is adjusted.
Supply oil from passage (9) flows through passage (10) to grapple control valve (32). The supply oil flows from grapple control valve (32) through passage (37) and check valve (34) to flow compensator valve (33) .
Since the supply oil is initially blocked by flow compensator valve (33), the oil flows through passage (36) and the oil pushes flow compensator valve (33) upward.
As flow compensator valve (33) shifts opens, supply oil flows from flow compensator valve (33) through passage (35) back to grapple control valve (32). The supply oil flows from grapple control valve (32) through line (16) to the rod end of grapple cylinders (18) and the grapple opens. As the grapple opens, oil is forced from the head end of grapple cylinders (18) through line (15) to grapple control valve (32). The return oil flows from grapple control through passage (38) and return passage (14) back to the hydraulic tank.
The GRAPPLE CLOSE operation is similar to the GRAPPLE OPEN operation.
When the slider on the right joystick is moved to the GRAPPLE CLOSE position, proportional solenoid valve (1) is energized. Pilot oil in passage (8) returns to hydraulic tank (30) and grapple control valve (32) shifts upward. The oil delivery from the rear pump now flows through line (15) to grapple cylinders (18) .
Grapple Rotate
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| Illustration 2 | g01416711 |
(1) Rotator motor (2) Line (3) Line (4) Makeup valve (5) Rotator valve (6) Line relief valve (7) Makeup valve (8) Line relief valve (9) Main relief valve (10) Passage (11) Control valve (12) Passage (13) Passage (14) Shuttle valve (15) Passage (16) Relief valve (17) Relief valve (18) Shuttle valve (19) Return passage (20) Supply passage (21) Line (load sensing signal) (22) Return line (23) Supply line (24) Pilot line (25) Solenoid valve (26) Solenoid valve (27) Pilot manifold (28) Front pump (29) Rear pump (30) Pilot pump (31) Hydraulic tank | |
Pilot oil is supplied from pilot pump (30) to pilot manifold (27). The pilot oil flows through the pilot manifold to solenoid valve (25) and solenoid valve (26).
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| Illustration 3 | g01134351 |
Left Joystick (32) Rotate counterclockwise (33) Rotate clockwise | |
By depressing slider (32), solenoid valve (25) is energized. Pilot oil flows through the solenoid valve to line (24) to rotator valve (5). The oil flows through passage (10) to control valve (11). Control valve (11) shifts downward.
Pump oil is supplied by front pump (28) and rear pump (29) through line (23) to rotator valve (5). The pump oil flows through passage (20) to control valve (11). The pump oil flows to rotator motor (1) through line (3). Line (3) is located on the right side of the stick.
When control valve (11) is shifted, signal oil is sent through passage (13) to shuttle valve (14) and relief valve (17). The oil then flows through passage (15) to shuttle valve (18). The oil in shuttle valve (18) flows through line (21) to the pump regulators. This is the load sensing signal to the pump. Relief valves (16) and (17) control the maximum pressure of the load sensing signal.
Hydraulic oil returns to hydraulic tank (31) from the motor through line (2) and line (22) .
Line relief valve (8) controls the oil pressure in the rotator circuit when the work tool is rotating clockwise. Main relief valve (9) controls the pressure in the rotator circuit.
To prevent cavitation in the rotator motor during travel stop, makeup oil is supplied to the rotator motor. When slider (32) is released, oil from the front pump (28) and the rear pump (29) is blocked by control valve (11). Since no oil delivery is supplied to rotator motor (1), the rotator motor will attempt to stop. However, the rotator motor will continue to rotate because of the inertia (weight and size) of the work tool. This causes a vacuum condition in line (2). The vacuum creates a pressure reduction in line (2) which allows oil to flow through makeup valve (4). This makeup oil prevents cavitation in the rotator circuit. The work tool rotates counterclockwise.
Note: Rotation of the work tool may be different between manufacturers.
When slider (33) is depressed solenoid valve (26) is energized and oil is sent through line (2) to rotator motor (1). Line (2) is located on the left side of the stick. Clockwise rotation functions in the same manner as counterclockwise rotation.