Patent ID: 8459173

Claim:
A bidirectional hydraulic system comprising: at least three movable units powered with multiple hydraulic cylinders; a bidirectional hydraulic pumping device configured to supply hydraulic power for the movable units; a switch valve configured to switch oil passages between the bidirectional hydraulic pumping device and the movable units wherein the switch valve comprises a valve block having a substantially rectangular shape, wherein multiple pairs of coupling holes are at multiple respective outbound valve positions on a top surface of the valve block, wherein each of the hydraulic cylinders connect with one of the outbound valve positions via an oil conduit, a rotating shaft extending horizontally through the valve block, wherein the rotating shaft is configured to select one of the outbound valve positions, and a motor connecting with the rotating shaft extending out of the valve block, wherein when one of the movable units is selected to work, the motor drives the rotating shaft to rotate, wherein the rotating shaft directs oil supply of the bidirectional hydraulic pumping device to a selected one of the outbound valve positions, wherein the selected one of the outbound valve positions directs the oil supply of the bidirectional hydraulic pumping device to the selected one of movable units; and a valve detecting element at an end of the rotating shaft, wherein the rotating shaft is configured to be positioned corresponding to the outbound valve positions, wherein the valve detecting element comprises multiple detecting plates mounted on the end of the rotating shaft, multiple detectors retained on the valve block and multiple partitioning rings partitioning the detecting plates, wherein each of the detectors straddles at an edge of one of the detecting plates.