GUARD AS 4W5968 - Caterpillar

Illustration 1 g01089136
Pipelayer hydraulic system (1) Lubrication outlet port (2) Lubrication inlet port (3) Winch for the boom (4) Winch motor for the boom (5) Lubrication outlet port (6) Lubrication inlet port (7) BOOM RAISE port (8) BOOM LOWER port (9) Brake release port (10) Return manifold (11) Lubrication inlet port (12) QUICK-DROP port (13) Lubrication outlet port (14) Hook winch (15) Lubrication outlet port (16) Hook winch motor (17) Combination valve (18) Brake release port (19) Lubrication inlet port (20) Port for winch speed (21) Drain port (22) Brake release port (23) HOOK LOWER port (24) HOOK RAISE port (25) LOWER motor port (26) RAISE motor port (27) Speed control valve (hook winch motor) (28) Hook pilot control valve (29) Boom pilot control valve (30) Counterweight cylinder (31) Counterweight control valve (32) Boom kickout valve (33) Auxiliary hydraulic pump (34) Main hydraulic pump (35) Oil cooler (36) Accumulator (37) Distribution manifold (38) Load sensing manifold (39) LOWER motor port (40) RAISE motor port (41) Brake release port (42) Hook control valve (43) Boom control valve (44) Manifold (45) Shutoff valve (AA) Pump pressure (PP) Pilot pressure (LL) Return oilOperating Principles
The hydraulic system is a continuous flow system that permits a minimum flow in the system when hook control valve (42), boom control valve (43) and counterweight control valve (31) are not in the activated position. Main hydraulic pump (34) and auxiliary hydraulic pump (33) work together to supply oil pressure to the hydraulic components.Counterweight Circuit
Auxiliary hydraulic pump (33) supplies oil for the counterweight hydraulic circuit and lubrication for the winches. When counterweight control valve (31) is operated, the oil goes to counterweight cylinder (30). The return oil from the cylinder exits valve (31) and the oil goes to oil cooler (35) in order to lower the oil temperature. When counterweight control valve (31) is in the HOLD position, the oil supply to valve (31) passes through the valve and the oil goes directly to oil cooler (35). The oil passes through oil cooler (34) to distribution manifold (37) for lubrication of the winches.Note: If oil cooler (35) ever becomes frozen or plugged, a bypass in counterweight control valve (31) reroutes the oil directly to distribution manifold (37) .Pilot Circuit
Main hydraulic pump (34) supplies oil for the boom and hook control valves and the pilot circuit. The oil from pump (34) travels to manifold (44). A portion of the oil travels through manifold (44) to the pilot circuit. Accumulator (36) is charged with this oil to the pilot pressure. After the accumulator is charged, the oil exits manifold (44) and pressure is sent to the pilot control valves. Speed control valve (27) controls the speed of hook winch motor (16). Hook pilot control valve (28) controls the operation of hook winch (14). Boom pilot control valve (29) controls the operation of winch (14) for the boom.Note: Shutoff valve (45) controls the flow of pilot oil to the controls. When valve (42) is in the OFF position, all of the