LINES GP-F PRM 4645141 - Caterpillar

Counterbalance Valve Operation
Illustration 1 g01079067
View of the front of the machineCounterbalance valve (1) is located on the front of the machine behind the radiator grill.
Illustration 2 g01078568
(1) Counterbalance valve (2) Relief valve (3) Solenoid valve (4) Solenoid valveCounterbalance valve (1) creates a back pressure that equals the weight of the blade in the circuit for the rod end of the lift cylinder when the lift control valve is in the Lower position. Solenoid (3) and solenoid (4) are energized when the AccuGrade System is in the auto mode only. When solenoids (3) and (4) are not energized and the blade lift control valve is in the raise position, oil is allowed to move freely through the counterbalance valve. Operation of the Counterbalance Valve in Blade Lower
Illustration 3 g01079061
(1) Counterbalance valve (2) Relief valve (3) Solenoid valve (4) Solenoid valve (5) Lift cylinders (6) Lift control valve (7) Bank valve (8) Pilot valveWhen the Accugrade System commands the blade to lower, pilot valve (8) remains in the neutral position. Bank valve (7) sends a pilot signal to the lower side of the lift control valve (6). High pressure oil is then sent to the head end of lift cylinders (5). Solenoid valves (3) and (4) block the return oil from the rod end to the tank. The oil must go through relief valve (2). Relief valve (2) will not allow oil to flow until pressure reaches the blade carry pressure. This creates a back pressure between the rod end of the lift cylinder and the counterbalance valve.The counterbalance valve is used to make the pressure requirements similar for the blade raise and blade lower functions. The AccuGrade System needs similar pressures for both the blade raise and the blade lower in order to function properly. Two solenoids are used in the counterbalance valve in order to handle the flow requirements that are needed when the AccuGrade System is not active.Operation of the Counterbalance Valve in Blade Raise
Illustration 4 g01079063
(1) Counterbalance valve (2) Relief valve (3) Solenoid valve (4) Solenoid valve (5) Lift cylinders (6) Lift control valve (7) Bank valve (8) Pilot valveWhen the AccuGrade System commands the blade to raise, check valves in solenoid (3) and solenoid (4) allow oil to flow to the rod end of the lift cylinders. No restriction to flow is created in the counterbalance valve.