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| Illustration 1 | g00791136 |
The Illustration above shows the Hydraulic System for the Quick Coupler when the Pins are being Disengaged. (1) Diverter valve (2) Coupler cylinder (quick coupler) (3) Load control valve for coupler cylinder (4) Bank valve (5) Signal relief valve (6) Line (load sensing) (7) Work tool cylinder (8) Rear section of stabilizer control valve (9) Front section of stabilizer control valve (10) Stabilizer control valve (11) Stabilizer cylinder (right side) (12) Stabilizer cylinder (left side) (13) Load control valve for left side stabilizer cylinder (14) Load control valve for right side stabilizer cylinder (15) End section of bank valve (16) Joystick (17) Implement section of bank valve (frame leveling) (18) Dual stage relief valve (19) Relief valve (coupler tilt) (20) Implement section of bank valve (boom extend/retract) (21) Pilot control valve (22) Solenoid valve (23) Solenoid valve (24) Solenoid valve (25) Solenoid valve (26) Pressure reducing valve (27) Brake reservoir (28) Hydraulic tank (29) Piston pump (30) Filter (31) Line (load sensing) (32) Inlet section of bank valve (33) Metering pump (34) Compensating cylinders (35) Valve (quick coupler pins) (36) Implement section of bank valve (boom raise/lower) (37) Load control valve for telescoping cylinder (38) Boom cylinder (boom raise/lower) (39) Implement section of bank valve (coupler tilt) (40) Load control valve for boom cylinder (41) Relief valve (coupler tilt) (42) Relief valve (43) Telescoping cylinder (boom extend/retract) (44) Implement section of bank valve (auxiliary section) (45) Valve (46) Load control valve for frame leveling cylinder (47) Frame leveling cylinder (48) Load control valve for tilt cylinder (49) Tilt cylinder (coupler tilt) (PP) Pump delivery (CP1) Coupler pins (pressure oil) (CP2) Coupler pins retract (pressure oil) (R) Return oil (S) Suction oil (LS) Load sensing pressure | |
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| Illustration 2 | g00781671 |
Quick coupler (2) Coupler cylinder | |
The pins for the quick coupler are engaged and disengaged by coupler cylinder (2) which is mounted on the quick coupler. The cylinder is equipped with two pistons. The pistons are extended in order to engage the pins, and the pistons are retracted in order to disengage the pins.
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| Illustration 3 | g00791140 |
Location of the diverter valve on the machine boom with handle (50) in the upper position (1) Diverter valve (50) Handle | |
The coupler cylinder is supplied with oil from implement section (44) of bank valve (4) through diverter valve (1). Handle (50) on the diverter valve must be rotated to the upper position in order to operate the pins for the quick coupler. The handle on the diverter valve must be rotated to the lower position in order to operate an auxiliary work tool.
Implement section (44) of the bank valve has a three-position spool that is operated by solenoids. The spool has a spring centered hold position. In the spring centered hold position, the spool blocks both of the work ports.
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| Illustration 4 | g00793532 |
Location of the switch on the joystick (16) Joystick | |
Implement section (44) of the bank valve is controlled by the switch on joystick (16). Refer to Operation and maintenance manual, SEBU7371, "Joystick Control" for full details of the quick coupler controls and operating procedures.
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| Illustration 5 | g00758399 |
Location of the Switch on the Instrument panel | |
When the pins for the quick coupler are being disengaged, the switch on the joystick and the switch on the instrument panel must be pressed at the same time.
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| Illustration 6 | g00791139 |
Location of the dual stage relief valve, solenoid, and line to the valve in the inlet section of the bank valve (18) Dual stage relief valve (51) Solenoid (52) Line | |
When the switch on the instrument panel is pressed, solenoid (51) is energized. The solenoid opens valve (35) in order to allow oil (CP2) to flow through line (52) to dual stage relief valve (18). The dual stage relief valve then controls pressure in the system at a higher value (setting). The switch on the joystick energizes a solenoid on implement section (44). Oil (CP1) flows from the implement section through diverter valve (1) to the rod sides of coupler cylinder (2). Pressure in the rod sides of the coupler cylinder is used as pilot pressure to open load control valve (3). Return oil (R) from the coupler cylinder flows through bank valve (4) and filter (30) to hydraulic tank (28) .
The lower setting of dual stage relief valve (18) is associated with the operation of a work tool via an auxiliary circuit which can be connected to diverter valve (1) .
When the pins for the quick coupler are being engaged, the switch on the joystick is operated in order to offset the spool in the implement section. Oil flows from the implement section through diverter valve (1) and load control valve (3) into the coupler cylinder. As the pistons in the coupler cylinder extend, the pins are installed through the work tool and through the quick coupler frame.
When the pistons in the coupler cylinder reach full travel, the pressure in the implement system is controlled by relief valve (42) that is installed in the bank valve.
When the switch on the joystick is released, the spool for the implement section is spring centered. Pressure between the spool and the coupler cylinder is relieved to the hydraulic tank through the bank valve.
As the pressure is relieved the load control valve is closed by spring force, locking oil between the pistons. This locks the coupler pins in the engaged position.