RELAY 0870546 - Caterpillar

Illustration 1 g01404352
Circuit for the quick coupler (1) Pilot coupler control valve (1A) Manual operated coupler control valve (2) Horizontal coupler (3) Vertical coupler (4) Auxiliary control valveNote: The manual operated coupler control valve (1A) controls the horizontal coupler (2) .Note: The pilot coupler control valve (1) controls the vertical coupler (3) .The quick coupler secures work tools and the quick coupler releases work tools. The pilot hydraulic system supplies oil to the quick coupler.When the coupler cylinders are extended, the coupler pins are engaged. When the coupler cylinders are retracted, the coupler pins are disengaged.When the quick coupler switch is in the LOCKED position, the solenoid valve (1) is de-energized and there is no movement of the coupler. If the coupler is in the extended position, the pins will be held in place by the spring force. If the coupler is in the retracted position, the pins will be held in place by the spring force.Note: The difference between the manual valve (1A) with the horizontal coupler (2) and the solenoid valve (1) with the vertical coupler (3) is manual power and electrical power.Horizontal Coupler with Mechanical Operation
This coupler is for use on the 906H and 908H machines. The coupler will use pressure from the auxiliary circuit (4) in order to engage the coupler pins. The coupler cylinder has a manual operated coupler control valve (1A) that will be normally closed. This will cut off the supply pressure from the auxiliary circuit to the head end of the coupler cylinder (2). When the manual operated coupler control valve (1A) is actuated, auxiliary supply pressure will actuate the cylinder (2) in both directions. The coupler cylinder is a double acting, double piston cylinder which is mounted horizontally. There is no continual extension of the coupler pins as the cylinder is horizontal. The coupler can stroke within 3 seconds or less.Vertical Coupler with Electrohydraulic Operation
As the mechanical horizontal type, this coupler will use pressure from the auxiliary circuit (4) to engage the coupler pins. The coupler will have a pilot coupler control valve (1) that will be normally closed. The continual extension of the coupler pins will be done with spring pressure and a mechanical system. The coupler cylinder (3) is mounted vertically and the cylinder has an orifice fitting in the rod end in order to restrict the speed of the system.Operation of the circuit is a rocker switch in the operator console. Refer to Operation and Maintenance Manual, SEBU8028, "906H, 907H and 908H Compact Wheel Loaders", "Operator Controls" for additional information. The switch will energize the appropriate pilot auxiliary coil. The coil will pressurize the auxiliary line and the coil will energize the coupler. This will allow the supply pressure from the auxiliary circuit to flow to the coupler cylinder (3) .