PULLEY-CRANKSHAFT 1691821 - Caterpillar

Function of Switches on Joysticks
Left Joystick
Illustration 1 g01258276
Functions of the switches on the left joystick (1) Grapple rotate counterclockwise (2) Grapple rotate clockwise (3) Horn (4) Magnet (On/Off)Right Joystick
Illustration 2 g01258280
Functions of the switches on the right joystick (5) Cab raise (6) Cab lower (7) Manual low idle (8) SmartBoom temporary disable switchOperation of Pilot Control Valve
Illustration 3 g00955145
Cross section of joystick (9) Port for bucket open (10) Port for boom lower (11) Port for bucket close (12) Port for boom raise (13) Port for swing left (14) Port for stick out (15) Port for swing right (16) Port for stick in (17) Control spool (18) Plunger (19) Return spring (20) Control spring (21) Passage (22) Line to tank (23) Line from pilot pump (24) Line to main control valve (25) PlateEach pilot control valve has four valves that control two operations. The left pilot control valve has two valves for the stick and two valves for the swing. The right pilot control valve has two valves for the boom and two valves for the bucket.When the joystick is moved to the right, plate (25) tilts to the left. Plate (25) pushes down on plunger (18). The seat pushes control spring (20) and return spring (19). The force of the control spring (20) moves control spool (17) downward and passage (21) is opened. The oil can go through the passages and out of port (24) through the line to the main control valve. The oil pressure that is generated at the pilot control valve moves the main control valve spools. This permits oil flow to the implements.The oil at the opposite end of the main control valve stem flows through the port return passage and to the return chamber and through port (22) to the hydraulic tank.Return spring (19) in the pilot control valve provides the necessary force in order to allow the joysticks to return to the NEUTRAL position when the joysticks are released.When the joystick is actuated, control springs (20) are compressed. This causes control spool (17) to move downward. Control spool (17) controls the pilot oil pressure to the main control valve. The pilot pressure that is delivered to the main control valve is proportional to the travel distance of the joystick. Movement of the main control valve stems causes a change in the flow rate of oil to the implements and/or the motors that is proportional to the change in pilot pressure.
Illustration 4 g00970775
The pilot pressure that is delivered to the main control valve is proportional to the travel distance of the joystick. This is shown in Illustration 4. The amount of change in the flow rate from the main control valve to the implements and/or motors is proportional to the change in pilot pressure from the joysticks.