| |
| Illustration 1 | g03416673 |
|
Hydraulic schematic for BUCKET CLOSE (1) Bucket cylinder (2) Line (3) Line (4) Main control valve (5) Pilot line (6) Implement pressure switch (7) Passage (8) Passage (9) Bucket control valve (10) Passage (11) Check valve (12) Passage (13) Return passage (14) Parallel feeder passage (15) Pilot line (16) Return line (17) Pilot control valve (19) Drive pump (18) Swing brake solenoid valve (20) Idler pump (21) Pilot pump | |
| |
| Illustration 2 | g03416696 |
|
Main control valve (9) Bucket control valve | |
The oil delivery from drive pump (19) flows through parallel feeder passage (14) in main control valve (4) to bucket control valve (9). The bucket control valve does not utilize the output flow from idler pump (20).
When the joystick for the bucket is moved to the BUCKET CLOSE position, the pilot oil flows from pilot pump (21) through pilot control valve (17) to pilot line (5). The pilot oil flows through pilot line (5) to bucket control valve (9). Pilot oil shifts the spool of bucket control valve (9) downward.
When the bucket control valve is shifted downward, the oil flow from drive pump (19) in parallel feeder passage (14) flows through passage (12) to check valve (11). The oil flows through check valve (11), through passage (10), and to bucket control valve (9). The oil flows through bucket control valve (9), through passage (7), and through line (3) to the head end of bucket cylinder (1). The oil extends the cylinder rod of bucket cylinder (1). The bucket closes.
Return oil from the rod end of cylinder (1) flows through line (2) and passage (8) to bucket control valve (9). The oil flows from the bucket control valve through return passage (13) and through return line (16) back to the hydraulic tank.
| |
| Illustration 3 | g03416720 |
|
Hydraulic schematic for BUCKET OPEN (1) Bucket cylinder (2) Line (3) Line (4) Main control valve (5) Pilot line (6) Implement pressure switch (7) Passage (8) Passage (9) Bucket control valve (10) Passage (11) Check valve (12) Passage (13) Return passage (14) Parallel feeder passage (15) Pilot line (16) Return line (17) Pilot control valve (19) Drive pump (18) Swing brake solenoid valve (20) Idler pump (21) Pilot pump | |
The BUCKET OPEN operation is similar to the BUCKET CLOSE operation.
The oil delivery from drive pump (19) flows through parallel feeder passage (14) in main control valve (4) to bucket control valve (9). The bucket control valve does not utilize the output flow from idler pump (20).
When the joystick for the bucket is moved to the BUCKET OPEN position, the pilot oil flows from pilot pump (21) through pilot control valve (17) to pilot line (15). The pilot oil flows through pilot line (15) to bucket control valve (9). Pilot oil shifts the spool of bucket control valve (9) upward.
When the bucket control valve is shifted upward, the oil flow from drive pump (19) in parallel feeder passage (14) flows through passage (12) to check valve (11). The oil flows through check valve (11), through passage (10), and to bucket control valve (9). The oil flows through bucket control valve (9), through passage (8), and through line (2) to the rod end of bucket cylinder (1). The oil retracts the cylinder rod of bucket cylinder (1). The bucket opens.
Return oil from the head end of cylinder (1) flows through line (3) and passage (7) to bucket control valve (9). The oil flows from the bucket control valve through return passage (13) and through return line (16) back to the hydraulic tank.
The implement pressure switch sends an input signal to the machine ECM. When the joysticks are moved from the NEUTRAL position for a boom UP, stick IN, stick OUT, bucket IN, or a bucket OUT operation, pilot oil is directed to the implement pressure switch (6). The increase of pilot pressure activates the implement pressure switch. The implement pressure switch sends an electrical signal to the machine ECM. The switch information is used to control engine speed and pump control. Also, an electrical signal from the machine ECM energizes swing brake solenoid valve (18) in order to release the swing parking brake.
Note: The implement pressure switch (6) does not detect a boom lower or a swing operation.