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| Illustration 1 | g01155598 |
Rotator Control Valve (HOLD Position) (1) Plug (2) Port to left side of rotator (3) Port to right side of rotator (4) Plug (5) Pilot oil chamber (6) Spring (7) Spring (8) Pilot oil chamber (9) Passage to tank (10) Signal passage (11) Springs (12) Port (13) Spring cavity (14) Passage (15) Passage (16) Pump passage (17) Spool (18) Chamber (19) Signal passage (20) Passage to tank (21) Control spool (22) Solenoid valve (23) Solenoid valve (24) Stroke limiters | |
The rotator control valve is located between the tong control valve and the end cover. Pump oil flows from the tong control valve into the rotator control valve through passage (16). Passage (16) is common in all control valves for the grapple and the passage has no outlet.
The grapple rotate switch is mounted on the grapple control lever. The grapple control lever is attached to the pilot valve. When the grapple rotate switch is in the HOLD position, solenoids (22) and (23) block the pilot oil from flowing to either chamber (5) or (8). Centering springs (6) and (7) keep control spool (21) in the HOLD position.
Oil flows into passage (15) through openings in spool (17). The oil then flows into chamber (18). The pressure in chamber (18) then rises.
As the pressure in chamber (18) rises, this pressure acts against spool (17). The pressure overcomes the force of springs (11) and spool (17) moves left. As spool (17) moves left, oil flows from passage (16) into passage (14). The oil in passage (14) is blocked by spool (21) .
As spool (17) moves left, slots in the spool begin to close. When the slots close oil flow from passage (16) to passage (14) is restricted. Oil flows from signal passage (10) into spring cavity (13) through port (12) .
Oil is now metered through the slots in spool (17) in order to maintain pressure in chamber (18) and passage (16) above the pressure in signal cavity (10). This pressure is lower than pump pressure in passage (16) .
In the HOLD position, spool (17) blocks the oil in passage (14) from flowing into either port (2) or port (3). The oil in the rotator motor and the oil lines are also blocked at ports (2) and (3) .
Since no oil is flowing to the rotator, oil in passages (9), (10), (12), (19), and (20) returns to the hydraulic tank.
Rotator (CLOCKWISE Position)
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| Illustration 2 | g01155598 |
Rotator Control Valve (CLOCKWISE Position) (1) Plug (2) Port to left side of rotator (3) Port to right side of rotator (4) Plug (5) Pilot oil chamber (6) Spring (7) Spring (8) Pilot oil chamber (9) Passage to tank (10) Signal passage (11) Springs (12) Port (13) Spring cavity (14) Passage (15) Passage (16) Pump passage (17) Spool (18) Chamber (19) Signal passage (20) Passage to tank (21) Control spool (22) Solenoid valve (23) Solenoid valve (24) Stroke limiters | |
When the grapple rotate switch is in the CLOCKWISE position, solenoid (22) is energized. Solenoid (22) then shifts and routes pilot oil to chamber (5). The pilot oil acts against spool (21). The pressure of the pilot oil overcomes the force of springs (7) and spool (21) moves right. Pump oil flows from the tong control valve into the rotator control valve through the passage (16). Oil flows into passage (15) through the openings in spool (17). The oil then flows into chamber (18). The pressure in chamber (18) then rises.
As the pressure in chamber (18) rises, this pressure acts against spool (17). The pressure overcomes the force of springs (11) and spool (17) moves left. As spool (17) moves left, oil flows from passage (16) into passage (14) .
As spool (21) starts to move right, oil flows past the spool into signal passage (10) and back to the pump control. This causes the pump to upstroke.
When spool (21) moves to the right far enough, the oil flows from passage (14) past the spool into port (2). Most of this oil flows into the rotator motor. This causes the motor to rotate clockwise.
Some of the oil in port (2) flows into signal passage (10). As the motor rotates, oil from the opposite side is forced outward. This oil flows into port (3), past spool (21) and into passages (19) and (20). The oil then flows from passage (20) back to the hydraulic tank.
When the grapple rotate switch is in the CLOCKWISE position, pressure in passage (12) is equal to the pressure in passage (10). The rest of the oil in port (2) flows through passage (10) to the secondary resolver in the arch control valve.
Stroke limiters (24) are mounted to end caps of the rotator control valve. Stroke limiters (24) restrict the travel of control spool (21). This regulates the flow of the oil to the rotator, which controls the speed of the rotator.
If the pressure of the resolver oil from the rotator is higher than the pressure of the resolver oil from any other circuit, the final resolver will shift. This allows the rotator oil to flow to the pump compensator valve. Now, the rotator oil is used to adjust the pump output that is required by the load.
When the operator releases the grapple rotate switch, pilot oil flow is blocked. Spring (7) at the right side of spool (21) will return the spool to the HOLD position. This blocks oil flow to the rotator motor and return flow from the rotator motor. The rotator will now remain in this position until the operator moves the grapple rotate switch again.
Rotator (COUNTERCLOCKWISE Position)
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| Illustration 3 | g01155598 |
Rotator Control Valve (COUNTERCLOCKWISE Position) (1) Plug (2) Port to left side of rotator (3) Port to right side of rotator (4) Plug (5) Pilot oil chamber (6) Spring (7) Spring (8) Pilot oil chamber (9) Passage to tank (10) Signal passage (11) Springs (12) Port (13) Spring cavity (14) Passage (15) Passage (16) Pump passage (17) Spool (18) Chamber (19) Signal passage (20) Passage to tank (21) Control spool (22) Solenoid valve (23) Solenoid valve (24) Stroke limiters | |
When the grapple rotate switch is in the COUNTERCLOCKWISE position, solenoid (23) is energized. Solenoid (23) then shifts and routes pilot oil to chamber (8). The pilot oil acts against spool (21). The pressure of the pilot oil overcomes the force of springs (6) and spool (21) moves left. Pump oil flows from the tong control valve into the rotator control valve through passage (16). Oil flows into passage (15) through the openings in spool (17). The oil then flows into chamber (18). The pressure in chamber (18) then rises.
As the pressure in chamber (18) rises, this pressure acts against spool (17). The pressure overcomes the force of springs (11) and spool (17) moves left. As spool (17) moves left, oil flows from passage (16) into passage (14) .
As spool (21) starts to move left, oil flows past the spool into signal passage (19) and back to the pump control. This causes the pump to upstroke.
When spool (21) moves left far enough, the oil flows from passage (14) past the spool into port (3). Most of this oil flows into the rotator motor. This causes the motor to rotate counterclockwise.
Some of the oil in port (3) flows into signal passage (19). As the motor rotates, oil from the opposite side is forced outward. This oil flows into port (2), past spool (21) and into passages (10) and (9). The oil then flows from passage (9) back to the hydraulic tank.
When the grapple rotate switch is in the COUNTERCLOCKWISE position, pressure in passage (12) is equal to the pressure in passage (19). The rest of the oil in port (3) flows through passage (19) to the secondary resolver in the arch control valve.
Stroke limiters (24) are mounted to end caps of the rotator control valve. Stroke limiters (24) restrict the travel of control spool (21). This regulates the flow of the oil to the rotator, which controls the speed of the rotator.
If the pressure of the resolver oil from the rotator is higher than the pressure of the resolver oil from any other circuit, the final resolver will shift. This allows the rotator oil to flow to the pump compensator valve. Now, the rotator oil is used to adjust the pump output that is required by the load.
When the operator releases the grapple rotate switch, pilot oil flow is blocked. Spring (6) at the left side of spool (21) will return the spool to the HOLD position. This blocks oil flow to the rotator motor and return flow from the rotator motor. The rotator will now remain in this position until the operator moves the grapple rotate switch again.