COVER AS 3533754 - Caterpillar

Illustration 1 g01520499
Location of toggle switch, lever and ball valves (4) Control valve (5) Lever (6) Ball valves (OPEN position) (9) Spool valve (10) Line (11) Solenoid valve (16) Line (17) Pilot drain line (23) Toggle switch
Illustration 2 g01520517
Partial hydraulic schematic (1) Main control valve (2) Stick I control valve (3) Stick II control valve (4) Control valve (5) Lever (6) Ball valves (7) Counterweight lifting cylinder (8) Check valve (9) Spool valve (10) Line (11) Solenoid valve (12) Proportional valve for negative flow control (13) Idler pump (14) Drive pump (15) Pilot pump (16) Line (17) Pilot drain line (18) Pilot manifold (19) Hydraulic lockout solenoid (20) Hydraulic tank (21) Drain line to hydraulic tank (22) Relief valveEnabling the Removal Device for the Counterweight
The hydraulic activation control lever must be in the LOCKED position in order to activate the counterweight removal circuit. Ball valves (6) must be in the OPEN position. The counterweight removal circuit is enabled by toggle switch (23) . Toggle switch (23) energizes solenoid valve (11) . Solenoid valve (11) shifts downward and pilot oil flows through solenoid valve (11) to line (10) . Pilot oil in line (10) shifts valve (9) . Pump oil flows from line (16) through spool valve (9) to control valve (4) .Pilot oil also flows through line (10) to Stick II control valve (3) and a shuttle valve in the NFC line to the drive pump regulator. Pilot oil pressure from solenoid valve (11) and the NFC signal are sent to the shuttle valve. The highest pressure is sent to the pump regulator in order to destroke the pump. This ensures that the pump flow to the counterweight cylinder is at a minimum flow.Counterweight Lower Operation
When lever (5) is pulled down, control valve (4) shifts downward. Pump oil flows through control valve (4) to the rod end of lift cylinder (7) . Oil drains from the head end of the lift cylinder and flows through relief valve (22) , ball valve (6) and control valve (4) . The oil flows through control valve (4) and line (21) to the hydraulic tank. The counterweight is lowered. Refer to Illustration 2.Counterweight Raise Operation
Illustration 3 g01521479
When lever (5) is pulled up, control valve (4) shifts upward. Pump oil flows through ball valve (6) to relief valve (22) . Pump oil flows through check valve (8) and to the head end of lift cylinder (7) . Oil drains from the rod end of lift cylinder (7) to control valve (4) . The oil flows through control valve (4) and line (21) to the hydraulic tank. The counterweight is raised. When lever (5) is placed in the NEUTRAL position, check valve (8) prevents the oil in the head end of lift cylinder (7) from flowing out of the lift cylinder. Refer to Illustration 3.Relief Operation of the Cylinder Head End
When counterweight lift cylinder (7) is pushed downward by an outside force the oil pressure in the head end of the lift cylinder increases. The oil pressure