Stick Out
 | |
| Illustration 1 | g03560057 |
Hydraulic schematic for STICK OUT (1) Pilot control valve (stick and swing) (2) Pilot line (3) Stick cylinder (4) Line (oil flow to stick cylinder rod end) (5) Line (oil flow from stick cylinder head end) (6) Return line (7) Valve (8) Stick drift reduction valve (9) Passage (10) Pilot line (11) Boom II control valve (12) Return passage (13) Stick I control valve (14) Return passage (15) Load check valve (16) Passage (17) Center bypass passage (18) Return passage (19) Pilot line (20) Main control valve (21) Passage (22) Center bypass passage (23) Parallel feeder passage (24) Check valve (25) Check valve (26) Stick II control valve (27) Center bypass passage (28) Drive pump (29) Idler pump (30) Pilot pump | |
 | |
| Illustration 2 | g02157976 |
Main control valve (8) Stick drift reduction valve (13) Stick I control valve (26) Stick II control valve | |
When the stick hydraulic circuit is operated independently of other hydraulic circuits, stick I control valve (13) and stick II control valve (26) are operational for both the STICK IN operation and the STICK OUT operation. When the stick I control valve and the stick II control valve are operated, the oil delivery from idler pump (29) and drive pump (28 ) is combined. The oil delivery from both pumps flows to stick cylinder (3) in order to perform a stick operation.
The oil delivery from drive pump (28) flows through parallel feeder passage (23) in main control valve (20) to stick II control valve (26) . The oil delivery from idler pump (29) flows through center bypass passage (17) in main control valve (20) to stick I control valve (13) .
When the joystick is moved to the STICK OUT position, the pilot oil flows from pilot control valve (1) through pilot line (2) . The pilot oil flow then divides into two flow paths. Part of the pilot oil flows through pilot line (10) to stick I control valve (13) in main control valve (20) . The remainder of the pilot oil flows through pilot line (19) to stick II control valve (26) in the main control valve.
The pilot oil in pilot line (10) shifts the spool of stick I control valve (13) . The oil delivery from idler pump (29) that is in center bypass passage (17) flows through load check valve (15) , passage (16) and passage (9) . The oil delivery from the idler pump then enters stick drift reduction valve (8) . Valve (7) shifts upward and the oil delivery flows through line (4) to the rod end of stick cylinder (3) .
The pilot oil in pilot line (19) shifts the spool of stick II control valve (26) . The oil delivery from drive pump (28) in center bypass passage (22) cannot flow through the stick II control valve to center bypass passage (27) and return passage (6) . Part of the oil delivery from the drive pump now flows through check valve (24) and the stick II control valve to passage (21) . The remainder of the oil delivery from the drive pump flows through parallel feeder passage (23) , check valve (25) , and the stick II control valve to passage (21) . All of the oil delivery from the drive pump in passage (21) combines with the oil delivery from the idler pump in passage (9) . The oil then flows to stick drift reduction valve (8) . The combined pump oil flows to the rod end of stick cylinder (3) . This combined pump oil causes the cylinder to retract at an increased rate of speed.
Return oil from the head end of the stick cylinder flows through line (5) and return passage (12) to stick I control valve (13) and stick II control valve (26) . The return oil then flows through return passage (14) and return line (6) to the hydraulic tank.
Stick In (Slow)
 | |
| Illustration 3 | g03583663 |
Hydraulic schematic for STICK IN (slow without regeneration) (3) Stick cylinder (4) Line (oil flow from stick cylinder rod end) (5) Line (oil flow to stick cylinder head end) (13) Stick I control valve (26) Stick II control valve (28) Drive pump (29) Idler pump (30) Pilot pump (31) Stick regeneration valve (32) Spring (33) Spring | |
When the joystick for the stick is moved less than half of the travel distance for STICK IN, low pilot oil pressure is supplied to stick I control valve (13) and stick II control valve (26) .
When the stick is moved at a low speed, stick I control valve (13) opens. The pilot pressure will not shift stick II control valve (26) or stick regeneration valve (31) . The force of spring (33) in stick I control valve (13) is less than the force of spring (32) in stick II control valve (26) . Because of the low pilot oil pressure, stick I control valve (13) will open and stick II control valve (26) will remain closed.
The oil delivery from idler pump (29) now flows to the head end of stick cylinder (3) . Without the oil delivery from drive pump (28) , the cylinder rod movement slows down when the stick is moved to the STICK IN position. The low speed operation of the stick is performed.
Stick In (Fast)
 | |
| Illustration 4 | g03560063 |
Hydraulic schematic for STICK IN (fast with regeneration) (1) Pilot control valve (stick and swing) (3) Stick cylinder (4) Line (oil flow to stick cylinder rod end) (5) Line (oil flow from stick cylinder head end) (6) Return line (7) Valve (8) Stick drift reduction valve (12) Return passage (13) Stick I control valve (14) Return passage (15) Load check valve (17) Center bypass passage (18) Return passage (20) Main control valve (22) Center bypass passage (23) Parallel feeder passage (24) Check valve (25) Check valve (26) Stick II control valve (28) Drive pump (29) Idler pump (30) Pilot pump (31) Stick regeneration valve (34) Pilot line (35) Pressure reducing valve for boom priority (36) Pilot line (37) Pilot line (38) Passage (39) Stick unloading valve (40) Passage (41) Passage (42) Boom II control valve (43) Passage | |
The STICK IN operation contains a regeneration circuit. When the joystick for the stick is moved to the STICK IN position, stick regeneration valve (31) and stick unloading valve (39) are operational in the stick hydraulic circuit. The return oil from the rod end of stick cylinder (3) is supplied to the head end of the stick cylinder. The regeneration circuit makes more effective use of the return oil from the stick cylinder. This action allows the oil delivery from the idler pump and the drive pump to perform other implement functions during a STICK IN operation.
When the joystick for the stick is moved to the STICK IN position, pilot oil from pilot control valve (1) flows through pilot line (34) . The pilot oil flow then divides into several flow paths. Part of the pilot oil flows through pilot line (36) to stick I control valve (13) . The pilot oil in pilot line (37) also flows to stick drift reduction valve (8) . Part of the pilot oil flows through pilot line (36) to stick regeneration valve (31) and to boom II control valve (42) . The remainder of the pilot oil flows through pressure reducing valve for boom priority (35) and pilot line (36) to stick II control valve (26) .
Since the pilot oil pressure has caused the spool in stick I control valve (13) to shift up, the oil delivery from idler pump (29) flows through center bypass passage (17) , load check valve (15) , stick I control valve (13) and passage (12) to line (5) .
The pilot oil pressure in pilot line (36) has caused the spool in stick II control valve (26) to shift up. Part of the oil delivery from drive pump (28) that is in center bypass passage (22) flows through check valve (24) and stick II control valve (26) . The remainder of the oil delivery from the drive pump flows through parallel feeder passage (23) , check valve (25) and stick II control valve (26) . All of the oil delivery from the drive pump combines with the oil delivery from the idler pump and flows to line (5) . The combined pump oil flows to the head end of stick cylinder (3) .
The return oil from the rod end of the stick cylinder flows through line (4) to stick drift reduction valve (8) . Valve (7) in the stick drift reduction valve shifts LEFT and the return oil enters passage (43) . Part of the return oil in passage (43) flows through stick I control valve (13) , return passage (14) , and return line (6) to the hydraulic tank. The remainder of the return oil flows through the regeneration circuit to the head end of the stick cylinder.
Stick Regeneration Valve
 | |
| Illustration 5 | g02173173 |
Stick regeneration valve (12) Passage (20) Main control valve (31) Stick regeneration valve (43) Passage (44) Port (45) Check valve | |
The stick hydraulic circuit contains a regeneration circuit. This regeneration circuit allows the return oil from the rod end of the stick cylinder to be supplied to the head end of the stick cylinder during the STICK IN operation.
When the joystick for the stick is moved to the STICK IN position, pilot oil flow from the pilot control valve (stick and swing) flows through pilot line (36) and into port (44) . Stick regeneration valve (31) shifts to the left. The return oil from the rod end of the stick cylinder flows through passage (43) and through the throttling slots on valve (31) to check valve (45) . Check valve (45) opens and the return oil flows through passage (12) . The return oil from the rod end of the stick cylinder in passage (12) combines with the oil delivery from the idler pump and the drive pump. This combined oil flow now flows into the head end of the stick cylinder.
Stick Unloading Valve
 | |
| Illustration 6 | g02310882 |
Stick unloading valve (12) Passage (20) Main control valve (31) Stick regeneration valve (38) Return passage (39) Stick unloading valve (43) Passage (44) Port (45) Check valve (46) Passage (47) Spring | |
Stick unloading valve (39) works with stick regeneration valve (31) in order to relieve high pressure in the head end of the stick cylinder during a STICK IN operation.
When the joystick for the stick is moved to the STICK IN position, pilot oil flow from the pilot control valve (stick and swing) flows through pilot line (36) to port (44) . Stick regeneration valve (31) shifts to the left. The return oil from the rod end of the stick cylinder flows through passage (43) and through the throttling slots on valve (31) to check valve (45) . Check valve (45) opens and the return oil flows through passage (12) . The return oil from the rod end of the stick cylinder in passage (12) combines with the oil delivery from the idler pump and the drive pump. This combined oil flow now flows into the head end of the stick cylinder.
Because of the volume of oil that is forced into the head end of the stick cylinder during the regeneration cycle of the STICK IN operation, the pressure of the oil in the head end of the stick cylinder increases. The high-pressure oil acts on the end of stick unloading valve (39) . When the force of the high-pressure oil becomes greater than the force of spring (47) , the stick unloading valve shifts to the right. The return oil from the rod end of the stick cylinder in passage (43) flows past the throttling slots on stick regeneration valve (31) . The oil then flows to stick unloading valve (39) , return passage (38) and into the return circuit to the hydraulic tank. The return oil from the rod end of the stick cylinder is quickly unloaded. At this time, the regeneration circuit for the stick cylinder is inoperable.
When the oil pressure at the head end of the stick cylinder decreases, the oil pressure that acts on the end of stick unloading valve (39) also decreases. The force of spring (47) shifts the stick unloading valve to the left. The return oil from the rod end of the stick cylinder is supplied to the head end of the stick cylinder. The regeneration circuit is again operable.