Stick Out
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| Illustration 1 | g00952530 |
Hydraulic schematic for STICK OUT (1) Stick lowering control valves (2) Stick cylinders (3) Passage (4) Line (5) Load check valve (6) Passage (7) Line (oil flow to stick cylinder head end) (8) Line (oil flow from stick cylinder rod end) (9) Line (10) Block (11) Main control valve (12) Return passage (13) Return passage (14) Load check valve (15) Return passage (16) Center bypass passage (17) Stick II control valve (18) Center bypass passage (19) Check valve (20) Passage (21) Check valve (22) Boom II control valve (23) Passage (24) Stick I control valve (25) Center bypass passage (26) Pilot line (27) Parallel feeder passage (28) Pilot line (29) Return line (30) Pilot control valve (stick and swing) (31) Pilot line (32) Pressure reducing valve (boom priority) (33) Left pump (34) Pilot pump (35) Right pump (36) Pilot line | |
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| Illustration 2 | g00946680 |
Main control valve (17) Stick II control valve (24) Stick I control valve | |
When the stick hydraulic circuit is operated independently of other hydraulic circuits, stick I control valve (24) and stick II control valve (17) are operational for the STICK OUT operation. When the stick I control valve and the stick II control valve are operated, the oil delivery from right pump (35) and left pump (33) is combined. The oil delivery from both pumps flows to stick cylinders (2) in order to perform a stick operation.
The oil delivery from right pump (35) flows through parallel feeder passage (27) in main control valve (11) to stick II control valve (17). The oil delivery from left pump (33) flows through center bypass passage (25) in main control valve (11) to stick I control valve (24) .
When the joystick for the stick is moved to the STICK OUT position, the pilot oil flows from pilot control valve (30) through pilot line (36). The pilot oil flow then divides into two flow paths. Part of the pilot oil flows through pilot line (26) to stick I control valve (24) in main control valve (11). The remainder of the pilot oil flows through pilot line (31), pressure reducing valve (32), and pilot line (28) to stick II control valve (17) in the main control valve.
The pilot oil in pilot line (26) shifts the spool of stick I control valve (24). The oil delivery from left pump (33) that is in center bypass passage (25) flows through load check valve (14), passage (20), passage (23), block (10), and line (7) to stick lowering control valves (1). The oil delivery from the left pump then flows through passage (6), load check valve (5), and passage (3) to the head end of stick cylinders (2) .
The pilot oil in pilot line (28) shifts the spool of stick II control valve (17). The oil delivery from right pump (35) in center bypass passage (16) cannot flow through stick II control valve (17) to center bypass passage (18) and return passage (15). Part of the oil delivery from the right pump now flows through check valve (19) and the stick II control valve to line (9). The remainder of the oil delivery from the right pump flows through parallel feeder passage (27), check valve (21) and the stick II control valve to line (9). All of the oil delivery from the right pump in line (9) flows to block (10) and combines with the oil delivery from the left pump. The combined pump oil flows to the head end of stick cylinders (2). This combined pump oil causes the cylinder to extend at an increased rate of speed.
Return oil from the rod end of the stick cylinders flows through line (8) and return passage (12) to stick I control valve (24). The return oil then flows through return passage (13) and return line (29) to the hydraulic tank.
Stick In
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| Illustration 3 | g00952534 |
Hydraulic schematic for STICK IN (1) Stick lowering control valves (2) Stick cylinders (7) Line (oil flow to stick cylinder head end) (8) Line (oil flow from stick cylinder rod end) (10) Block (11) Main control valve (12) Return passage (13) Return passage (14) Load check valve (15) Return passage (16) Center bypass passage (17) Stick II control valve (20) Passage (22) Boom II control valve (24) Stick I control valve (25) Center bypass passage (30) Pilot control valve (stick and swing) (32) Pressure reducing valve (boom priority) (33) Left pump (34) Pilot pump (35) Right pump (37) Check valve (38) Valve (39) Passage (40) Pilot line (41) Return line (42) Pilot line (43) Pilot line (44) Pilot line (45) Check valve (46) Stick regeneration valve (47) Stick unloading valve (48) Pilot line (49) Pilot line (50) Pilot line | |
When the joystick for the stick is moved to the STICK IN position, pilot oil from pilot control valve (30) flows through pilot line (50). The pilot oil flow then divides into several flow paths. Part of the pilot oil flows through pilot line (43), and pilot line (44) to stick I control valve (24). The pilot oil in pilot line (42) flows through pilot lines (40) to stick lowering control valves (1). The remainder of the pilot oil flows through pilot line (51) to stick regeneration valve (49) .
Note: The stick regeneration valve does not function for material handlers.
Note: Stick II control valve (17) is not functional for a STICK IN operation. The oil delivery from the right pump flows through center bypass passage (16) to the hydraulic tank and the negative flow control line. The right pump will remain at standby pressure.
Since the pilot oil pressure has caused the spool in stick I control valve (24) to shift downward, the oil delivery from the left pump flows through center bypass passage (25), load check valve (14), stick I control valve (24), passage (12), and line (8) to the rod end of stick cylinders (2) .
The return oil from the head end of the stick cylinders flows through stick lowering control valves (1). Pilot oil pressure opens valve (38) and check valve (37) in the stick lowering control valves. The return oil flows through passages (39) and return line (41) to the hydraulic tank.