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| Illustration 1 | g01061606 |
The counterbalance valve (1) is located on the right hand frame rail underneath the floorplate.
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| Illustration 2 | g01065277 |
Counterbalance 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) is energized when the AccuGrade System is in the auto mode only. When solenoid (3) is 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
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| Illustration 3 | g01096956 |
(1) Counterbalance valve (2) Relief valve (3) Solenoid valve (4) Lift cylinders (5) Lift control valve (6) Bank valve (7) Pilot valve | |
When the Accugrade System commands the blade to lower, pilot valve (7) remains in the neutral position. Bank valve (6) sends a pilot signal to the lower side of the lift control valve (5). High pressure oil is then sent to the head end of lift cylinders (4). Solenoid valve (3) blocks 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.
Operation of the Counterbalance Valve in Blade Raise
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| Illustration 4 | g01096958 |
(1) Counterbalance valve (2) Relief valve (3) Solenoid valve (4) Lift cylinders (5) Lift control valve (6) Bank valve (7) Pilot valve | |
When the AccuGrade System commands the blade to raise, the check valve in solenoid valve (3) allows oil to flow to the rod end of the lift cylinders. No restriction to flow is created in the counterbalance valve.