Air powered hydraulic jack with load sensing auto shut-off air control

摘要

The invention provides an improved fluid motor powered lift system having a valve arrangement for reducing or interrupting the fluid flow supplied to the motor when the pressure in the lift system exceeds a predetermined pressure. A valve arrangement is provided to shut-off or throttle back the fluid supplied to the fluid motor when the fluid pressure in the lift reaches a predetermined level. When the pressure in the lift system exceeds the predetermined level, pilot pressure is supplied to an automatic shut-off valve, and this in turn reduces fluid flow to fluid air motor thereby reducing or preventing pump pressure.