BOOM CYLINDER GP-LINES & 4I1876 - Caterpillar

Illustration 1 g00551584
(1) Wheel brake (2) Oscillating axle accumulator (3) Oscillating axle cylinder (4) Bottom swivel (5) Wheel brake valve (6) Wheel brake pedal (7) Brake cylinder (single acting) (8) Power brake valve (9) Brake light pressure switch (10) Parking brake (11) Spring accumulator (12) Wheel brake accumulators (13) Low brake pressure switch (14) Accumulator charging valve (15) Transmission (16) Top swivel (17) Oscillating axle operating brake valve (18) Downshift inhibitor (19) Low transmission clutch pressure switch (20) Parking brake solenoid valve (21) Transmission clutch accumulator (22) Transmission shift and parking brake control valve (23) Transmission shift solenoid (24) Parking brake relief valve (25) Pilot accumulator (26) Pilot manifold (27) Gear pump (brake and pilot) (28) Hydraulic tank (29) Control valve for pilot flow (separate auxiliary circuit) (30) Pilot pressure relief valveSystem
Illustration 2 g00551586
Wheel and parking brake components (5) Wheel brake valve (12) Wheel brake accumulators (16) Top swivel (17) Oscillating axle operating brake valve (21) Transmission clutch accumulator (22) Transmission shift and parking brake control valve (26) Pilot manifold (27) Gear pump (brake and pilot) (28) Hydraulic tankThe wheel and parking brake systems are hydraulically operated. The pressure for the brake systems is supplied by gear pump (27) that is mounted on the engine. The oil is supplied from the gear pump to wheel brake valve (5) .The accumulator charging valve in wheel brake valve (5) blocks the oil supply to wheel brake accumulators (12) when the cutoff pressure of15000 kPa (2175 psi) has been reached. When the pressure drops to approximately 12000 kPa (1750 psi), the accumulator charging valve allows oil to flow to wheel brake accumulators (12) .The oil pressure from port "N" on wheel brake valve (5) supplies oil to pilot manifold (26). Pilot manifold (26) directs oil to the control valve for pilot flow. The control valve for pilot flow supplies oil to the pilot circuit at a rate of 15 L/min (4 US gpm). The remainder of the oil is supplied to the attachments.The shuttle valve in wheel brake valve (5) directs the oil flow from gear pump (27) to both of the wheel brake circuits.When oscillating axle operating brake valve (17) is placed in position I, wheel brakes (1) are released and oscillating axle cylinders (3) are released. Pilot oil pressure is sent through top swivel (16) to oscillating axle cylinders (3). The oil opens the check valves inside the cylinders in order to unlock the oscillating axle cylinders. The oscillating axle cylinders now allow the front axle to oscillate.When oscillating axle operating brake valve (17) is placed in position II, wheel brakes (1) are released and the oscillating axle cylinders are in the LOCKED position.When oscillating axle operating brake valve (17) is placed in position III, all wheel brakes (1) are activated and the oscillating axle cylinders are in the LOCKED position. Position III is used for digging.