KIT-GASKET 4437601 - Caterpillar

Illustration 1 g03371235
Stick lowering control valve (1) Stick lowering control valve (2) Stick cylinderStick lowering control valve (1) is located on the head end of stick cylinder (2) .Stick lowering control valve (1) prevents the stick from falling if a hydraulic supply line fails or if a supply tube fails.Note: Stick lowering control valve (1) is supplied only when there is a boom lowering control valve.ReferenceFor information on lowering the boom manually, see Operation and Maintenance Manual, "Equipment Lowering with Engine Stopped".
Illustration 2 g03371250
Simplified hydraulic schematic (stick lowering control valve) (1) Stick lowering control valve (2) Stick cylinder (3) Main control valve (4) JoystickOperations for Stick Lowering Control Valve
Illustration 3 g03371257
(1) Stick lowering control valve (2) Stick cylinder (3) Main control valve (4) Joystick (5) Inlet port (6) Sealing face (7) Outlet port to rod end of stick cylinder (8) Spool 1 (9) Chamber (10) Passage to drain (11) Piston (12) Inlet port for pilot oil (13) Chamber (14) Spool 2 (15) Relief valve (16) ChamberSTICK IN Operation
When joystick (4) is moved to the STICK IN position, the pump oil flows from main control valve (3) to stick lowering control valve (1) . The pump oil flows through port (5) . Pilot oil will move spool (8) downward. Pump oil then flows through the passage to outlet port (7) and to the head end of stick cylinder (2) .STICK OUT Operation
When joystick (4) is moved to the STICK OUT position, pilot oil flows from joystick (4) to port (12) . Pilot oil will move piston (11) downward. When piston (11) moves downward, hydraulic oil from chamber (9) flows through passage (10) . Pump oil will open spool (8) . Hydraulic oil then flows from port (7) to port (5) and back to the tank.Stick Hold
When joystick (4) is moved to the NEUTRAL position, stick cylinder (2) is held in position. Spool (8) moves upward due to spring force in chamber (9) . Spool (8) will then seal against sealing face (6) . Spool (8) prevents oil from leaking from port (7) to port (5) .Relief Operation of the Cylinder Rod End
When the stick is pushed inward by an outside force, the oil pressure in port (7) increases. The oil pressure is sensed at relief valve (15) . When oil pressure overcomes the relief valve setting, relief valve (15) allows oil to fill chamber (16) . The oil pressure in chamber (16) moves spool (14) downward. Oil then flows from chamber (9) to passage (10) . Pump oil will open spool (8) . Hydraulic oil will then flow from port (7) to port (5) and back to the tank. The opening of port (7) lowers the hydraulic oil pressure until the hydraulic oil pressure is lower than the relief valve setting.