PIN AS 1239061 - Caterpillar

Illustration 2 g03189876
(12) Ejector pressure relief valve
(14) Ejector control valve
(15) Brake oil cooler relief valve
(20) Hoist proportioning solenoid for hold and retract
(21) Hoist proportioning solenoid for eject
(40) Actuators Ejector control valve (14) is located on the right side of the front frame.
Illustration 3 g03189878
(12) Ejector pressure relief valve
(14) Control valve (Ejector)
(16) Centering springs
(17) Stem
(20) Hoist proportioning solenoid for hold and retract
(21) Hoist proportioning solenoid for eject
(40) Actuators
Illustration 4 g03189877
(12) Ejector pressure relief valve
(14) Ejector control valve
(15) Brake oil cooler relief valve
(17) Stem
(19) Make up valve Oil flows from brake and pilot pump section of the gear pump (36) through check valve (32) to pilot oil pressure reducing valve (31). Pilot oil pressure reducing valve (31) maintains a constant pilot oil pressure to the parking brake, and to the steering and hydraulic pilot circuits. From pilot oil pressure reducing valve (31), the pilot oil flows through pilot oil filter (35). This oil is then divided.Some of the pilot oil flows to the parking brake circuit through check valve (27) and line (29). The rest of the pilot oil flows to the implement and steering solenoid valve (23).When implement and steering solenoid valve (23) is energized, pilot oil flows through lines (24) to steering metering pump and steering lockout valve. Also pilot oil flows to hoist proportioning solenoid for eject (21) and hoist proportioning solenoid for hold and retract (20).Hoist proportioning solenoid for hold and retract (20) and hoist proportioning solenoid for eject (21) are used to drain the pilot oil from the ends of stem (22). Draining the pilot oil allows stem (22) to move.Oil flows from hoist and brake cooling pump section (33) of the gear pump to ejector control valve (14). Ejector control valve (14) will direct pump oil to one of two locations. When the ejector plate is extended or retracted, ejector cylinders (4) and tailgate cylinders (5) receive the oil. When the ejector is not being used, the oil flows to the oil cooling system for the brakes.Brake oil cooler relief valve (15) limits the pressure in the brake oil cooling system. Brake oil cooler relief valve (15) will return oil to hydraulic tank (37) when brake oil cooling pressure is too high.Ejector pressure relief valve (12) limits the pressure to the rod end and the head end of ejector cylinders (4). Ejector pressure relief valve (12) will open when the pressure in the rod end and the head end of ejector cylinders (4) becomes too high. When ejector pressure relief valve (12) opens, make up valve (19) will open, and oil will return to hydraulic tank (37).HOLD Position
In the HOLD position, neither of the hoist proportioning solenoids are receiving current. The pilot oil is blocked by actuators (40). Centering springs (16) hold stem (22) so that oil in the head end of ejector cylinders (4) is blocked by stem (22).Stem (22) is in a position that allows pump oil to flow to