PLATE AS 3427434 - Caterpillar

Illustration 1 g00118123
Pilot Valve (STIC Steering)
(1) Handle
(2) Link
(3) Link
(4) Plunger
(5) Plunger
(6) Centering spring
(7) Centering spring
(8) Cap
(9) Cap
(10) Spring seat
(11) Spring seat
(12) Centering spring
(13) Centering spring
(14) Port (to hydraulic tank)
(15) Spring
(16) Spring
(17) Passage
(18) Passage
(19) Metering spool
(20) Metering spool
(21) Port (to neutralizer valve for left turns)
(22) Inlet (from selector valve and pressure control valve)
(23) Port (to neutralizer valve for Right turns)With the engine in operation, pilot oil flows from the selector and pressure control valve to the pilot valve (STIC Steering). Oil enters the valve at inlet port (22).The STIC steering control lever is attached to handle (1). When the STIC steering control lever is in the STRAIGHT AHEAD position, centering springs (6), (7), (12), (13), (15) and (16) keep the pivot plate in the CENTERED position.Pilot oil flows through inlet (22) to metering spools (19) and (20). In this position, the spools block the flow of oil to the steering control valve. This causes the oil to flow back to the hydraulic tank for the steering and brake systems.When the STIC steering control lever is moved to the LEFT TURN position, the pivot plate causes link (2) to move plunger (4) downward.As the plunger moves downward, the plunger overcomes the force of centering spring (6). This causes the spring to move downward. As the plunger moves downward