CONTROL GP-HOIST 2151557 - Caterpillar

Introduction
Illustration 3 g03369879
Main control valve (front view) (1) Main control valve (4) Right travel control valve (5) Left travel control valve (6) Line relief valve (attachment) (8) Line relief valve (attachment) (9) Attachment control valve (10) Swing control valve (11) Line relief valve (boom cylinder rod end) (12) Boom control valve (14) Line relief valve (boom cylinder head end) (13) Boom drift reduction valve (15) Line relief valve (bucket cylinder head end) (16) Bucket control valve (17) Line relief valve (bucket cylinder rod end) (18) Line relief valve (stick cylinder head end) (19) Stick control valve (20) Line relief valve (stick cylinder rod end)Main control valve (1) is located in the hydraulic system between the hydraulic pump and actuators (cylinders and motors). Depending on the machine operation, components and passages in the valves control, oil flow, and pressure in the circuits from the main pump (25) so that the actuators operate at optimum speed and in the correct direction. These functions also limit the pressure within the hydraulic system.Main control valve (1) has two distinct paths of supply oil.
The following control valves are in parallel in main control valve (1) .
Right travel control valve (4)
Left travel control valve (5)
Attachment control valve (9) .
Swing control valve (10) .
Boom control valve (12) .
Bucket control valve (16)
Stick control valve (19) The following components are also installed in main control valve (1) .
Line relief valves
Line relief valve (6) for the attachment cylinder
Line relief valve (8) for the attachment cylinder
Line relief valve (11) for the rod end of the boom cylinder
Line relief valve (14) for the head end of the boom cylinder
Line relief valve (15) for the head end of the bucket cylinder
Line relief valve (17) for the rod end of the bucket cylinder
Line relief valve (18) for the head end of the stick cylinder
Line relief valve (20) for the rod end of the stick cylinder
Drift reduction valve
Boom drift reduction valve (13) prevents boom cylinder drift, when main control valve (1) is in the NEUTRAL position.The oil from main pump (25) , is delivered through inlet port (P) , parallel feeder passage (28) , and return ports (T) and (T2) to hydraulic tank (26) .The following four configurations are the functions of main control valve (1) .
Main control valve (1) is in the NEUTRAL position. No load is placed on cylinders and motors.
Individual valve operation
Prevention of cylinder drift with the load check valve.
Limit the circuit pressure with the relief valve operation.The description of some components that are installed on main control valve (1) or in main control valve (1) will be listed separately. Refer to the appropriate sections that are in this module for further information on the components.Main Control Valve Operation In Neutral Position
Illustration 4 g03369971
Main control valve (neutral position) (1) Main control valve (2) Return line (4) Right travel control valve (5) Left travel control valve (7) Return passage (9) Attachment control valve (10) Swing control valve (12) Boom control valve (13) Boom drift reduction valve (16) Bucket control valve (19) Stick