DOOR AS 4717704 - Caterpillar

HANDLE RETURN MECHANISM
1. Plunger. 2. Handle. 3. Actuator assembly.Pressure air from the reservoir enters the valve body through the supply port (not shown) and is directed through passages in the body to air chambers (8) and (10). When the control handle is moved counterclockwise, the plunger (4) is moved to the left by the pin on the actuator assembly. This movement seats the left end of the plunger against valve (11), sealing exhaust port (14) from delivery port (13). The valve is also raised from its seat (12) in the valve body, allowing pressure air in air chamber (8) to pass through delivery port (13) to the left brake rotochamber applying the left brake.
SELECTOR BRAKE CONTROL VALVE
3. Actuator assembly. 4. Plunger. 5. Valve seat. 6. Plate. 7. Valve. 8. Air chamber. 9. Plate. 10. Air chamber. 11. Valve. 12. Valve seat. 13. Delivery port. 14. Exhaust port. 15. Delivery port. 16. Drilled passages.When the control handle is moved clockwise the valve plunger moves to the right actuating valve (7) in a similar manner. Pressure air passes from air chamber (10) through delivery port (15) to the right brake chamber applying the right brake. The delivery port (13) to the left brake chamber remains open to atmosphere through drilled passages and the exhaust port.Control Valve For The Retarder
The air control valve for the retarder controls the braking capacity of the retarder by letting air pressure go to the hydraulic control valve at a specific rate. When the handle for the control valve is moved toward the APPLIED position, the braking capacity of the retarder becomes higher.As the handle is moved toward the APPLIED position, head (1) and cam follower (2) are turned. This puts force on the top of regulating spring (4) through the cam follower and cam (3). The regulating spring moves piston (5) down, engaging the exhaust valve seat in the piston with the exhaust valve (6). The exhaust passage (11) is closed from delivery passage (9). The exhaust valve (6) and the inlet valve (10) are a rigid assembly. So, after the exhaust valve is closed, the inlet valve is moved off its seat. This lets air pressure from supply passage (12) go around the inlet valve to the delivery passage (9) to activate the hydraulic control valve for the retarder.The maximum air pressure from delivery passage (12) is 80 5 psi (5.6 0.4 kg/cm2).
RETARDER AIR CONTROL VALVE
1. Head. 2. Cam follower. 3. Cam. 4. Pressure regulating spring. 5. Piston. 6. Exhaust valve. 7. Spring. 8. Spring. 9. Delivery passage. 10. Inlet valve. 11. Exhaust passage. 12. Supply passage.When the air pressure below piston (5) becomes higher, it will lift the piston enough to permit the inlet valve to close on its seat. The supply passage (12) is closed. The exhaust valve (6) is still on its seat, preventing any loss of air pressure through the exhaust passage (11). The air pressure in the control valve both above and below the piston is the