HOUSING AS-FLY 6I2384 - Caterpillar

Illustration 2 g03551737
(1A) Limit switch to activate the brake lights Brake control valve (service) (2) controls the flow of pressurized oil. When service brake pedal (1) is depressed, rod (3) actuates the service brake control valve. The position of the brake pedal causes a specific pressure at the service brakes. As the position of the pedal changes, the pressure at the service brake also changes. There is a limit switch located at (1A). When the brake pedal is activated, the brake pedal activates limit switch (1A). The limit switch will send an electrical signal to the brake lamps causing the brake lamps to turn on.Disengaged Position
Illustration 3 g03859175
View from bottom of the machine
Service brake pedal in the DISENGAGED position
(4) Piston
(5) Tank port
(6) Outlet to left service brakes
(7) Passage
(8) Drain port
(9) Cavity
(10) Lower valve spool
(11) Tank port
(12) Outlet to right service brakes
(13 ) Cavity
(14) Spring
(15) Supply for the right brakes
(16) Lower valve spool passage
(17) Passage
(18) Upper valve spool passage
(19) Supply for the left brakes
(20) Upper valve spool
(21) Spacer
(22) Ball
(23) Retainer
(24) Spring
(25) Spring
(26) Low bias spring When the service brake pedal is in the disengaged position, the right and the left service brakes are drained to the tank. Oil flows from the service brakes through outlet (6) and outlet (12). The oil flows through passage (7) and passage (17) into the tank return port (5) and tank return port (11).Partially Engaged Position
Illustration 4 g03859298
View from bottom of the machine
Service brake pedal in the PARTIALLY ENGAGED position
(4) Piston
(5) Tank port
(6) Outlet to left service brakes
(7) Passage
(8) Drain port
(9) Cavity
(10) Lower valve spool
(11) Tank port
(12) Outlet to right service brakes
(13 ) Cavity
(14) Spring
(15) Supply for the right brakes
(16) Lower valve spool passage
(17) Passage
(18) Upper valve spool passage
(19) Supply for the left brakes
(20) Upper valve spool
(21) Spacer
(22) Ball
(23) Retainer
(24) Spring
(25) Spring
(26) Low bias spring When the brake pedal is depressed, the rod on the pedal assembly pushes piston (4) downward. Piston (4) applies a force on spring (25) and spring (24). The force of spring (25) and spring (24) moves retainer (23) and ball (22). Movement of retainer (23) and ball (22) causes upper valve spool (20) to move away from the seat in spacer (21).The movement of upper valve spool (20) causes the movement of lower valve spool (10) and the compression of spring (14). When valve spool (20) and valve spool (10) move, oil flow through passages (7) and (9) to tank return ports (5) and (11) is blocked.This allows pressurized oil from the supply port (15) and supply port (19) to flow through passages (7), (18), (17) and (16). The oil then flows through passages (6) and (12) in order to engage the service brakes. At the same time, pressurized oil flows through passage (16) and passage (18) and into cavities (9) and (13). The oil pressure at the service brakes has the same pressure as the oil in cavities (9) and (13).Oil pressure in cavity (13) and the force of spring (14) act to balance lower valve spool (10) against the force