FLANGE 8E8549 - Caterpillar

Illustration 1 g02426456
(1) Cab floorplate
(2) Hydraulic shuttle valve (resolver valve)
(3) Straight travel pedal assembly
(4) Pilot control valve (auxiliary pedal) The hydraulic control is bolted to cab floorplate (1) on the right side of the travel pedals. The hydraulic control consists of hydraulic shuttle valve (2), straight travel pedal assembly (3) and pilot control valve (4).The auxiliary pedal is operated by depressing the pedal forward or backward. Depressing the pedal forward causes the machine to travel straight forward. Depressing the pedal backward causes the machine to travel in straight reverse.
Illustration 2 g02426536
Travel pedal assemblies
(3) Straight travel pedal assembly
(5) Left travel pedal
(6) Right travel pedal
Illustration 3 g02426636
Partial Schematic (Forward Travel)
(2) Hydraulic shuttle valve (resolver valve)
(4) Pilot control valve (auxiliary pedal)
(7) Pilot control valve (left travel)
(8) Pilot control valve (right travel)
(9) Manifold for pilot supply oil
(10) Left travel motor
(11) Right travel motor
(12) Main control valve
(13) Pilot oil manifold
Illustration 4 g02428157
Pilot Control Valve
(14) Pilot oil supply port
(15) Passage
(16) Rod
(17) Seat
(18) Spring
(19) Spring
(20) Stem
(21) Passage
(22) Port The description that follows is for forward travel. The operation is similar for reverse travel.When the hydraulic activation control valve is activated, pilot oil is supplied to manifold (9). Pilot oil flows from manifold (9) to port (14) of pilot control valve (4). The pilot oil at port (14) flows into passage (15).When pedal (3) is depressed forward, rod (16) and seat (17) are pushed down against the force of springs (18) and (19). When stem (20) moves down, passage (21) is opened to passage (15).As passage (21) is opened, the pilot oil in passage (15) flows through passage (21) to port (22).The pilot oil flows from port (22) through hydraulic shuttle valve (2).
Illustration 5 g02428159
Hydraulic Shuttle Valve
(23) Inlet port for straight travel
(24) Inlet port for right travel
(25) Inlet port for left travel
(26) Outlet port
(27) Outlet port
(28) Check ball
(29) Check ball The pilot oil flows to port (23). The pilot oil pressure pushes check ball (28) and check ball (29) against port (24) and port (25). The check balls prevent pilot oil flow from port (24) and port (25). The pilot oil flows out of port (26) and port (27).The pilot oil flows to main control valve (12). The pilot oil shifts both of the travel control valves which provides main pump oil equally to the travel motors. The machine travels forward.