Rotary hydraulic jack device

Claim 1

A rotary hydraulic jack device for controlling a clamping chuck comprising: a rotary cylinder body with a first and second end cover tightly fastened thereto; a piston slidably guided in said cylinder body defining therein two compartments tightly separated from each other; a rotary hydraulic joint having a stationary part and a rotary part formed by a tubular extension of said cylinder first end cover; first and second main pipes connected to said rotary part, said first main pipe carrying a pressurized fluid, said second main pipe providing a discharge path for a fluid; first and second valves located within the first cylinder body end cover of said rotary cylinder body, said first valve being connected between one of said compartments and said first main pipe, said second valve being connected between said second main pipe and the remaining compartment, said valves comprising: a housing, each of said housings being located opposite each other and symmetrical with respect to the rotational axis of said rotary cylinder, said housings having a first opening for communicating with one of said main pipes, and a second opening communicating with one of said compartments; a slide member located within each housing and positionable between first and second ends of said housing, said slide member having at one end a jet communicating with a first end of said housing, and an axial channel connecting said jet via port means with that portion of the housing which communicates with one of said main pipes, said axial channel having lateral openings for communicating with said second opening, said lateral openings being closed by a pressure-sensitive annular elastic ring serving as a check valve for permitting flow towards said second opening, said slide member further including a sealing joint opening upon movement of said slide member to permit return flow from said second opening, first and second auxillary pipes connecting the second ends of each housing with a main pipe supplying the other housing; said valves operating in response to pressure being applied to one of said main pipes, whereby a slide of a valve receiving said pressure is moved to the second end of said housing as fluid passes through said jet, and a slide of the remaining valve is moved to the first position as fluid enters said second end of the remaining valve through said auxillary pipes.