Hydraulic cylinder for providing reciprocation of a hydraulic jack

Claim 1

A hydraulic fluid circuit system for providing pressurized control fluid to provide cyclic operation of a double-action hydraulic jack, said system including a hydraulic jack cylinder, a piston mounted in said hydraulic cylinder for reciprocation, said piston having a first face defining one side of a first chamber in said hydraulic chamber and a second face on an opposite side, said second face being smaller than said first face and defining one side of a second chamber in said hydraulic cylinder, a piston rod extending from said second face and being at least partly contained within said second chamber, said hydraulic cylinder, piston and piston rod comprising said hydraulic jack, a fluid reservoir, a distributor valve means positionable in first and second positions, a first conduit connecting said distributor valve means to one of said chambers, a second conduit connecting said distributor valve means to said fluid reservoir, a third conduit connecting said distributor valve means to a fluid accumulator which comprises a source of pressurized fluid, a conduit connecting said second chamber to the output of a pump to provide movement of said piston toward said first chamber when said first chamber is below a predetermined pressure level, said distributor valve means including means defining a passageway providing communication between said first conduit and said third conduit while simultaneously blocking said second conduit when said distributor valve means is in its said first position, said distributor valve means further including means directly communicating said first conduit with said second conduit while simultaneously blocking said third conduit when said diStributor valve means is in its second position, a fluid-actuated rotary engine having an inlet and an exhaust, coupling means coupling said rotary engine to said distributor valve means for moving said distributor valve means between said first position and said second position, a fourth conduit connecting the inlet of said rotary engine to the fluid accumulator, a flow restriction means mounted in said fourth conduit, a fifth conduit connecting the exhaust of said rotary engine to said fluid reservoir, calibrated pressure responsive valve means mounted in said fifth conduit between said fluid reservoir and said exhaust of the rotary engine, a sixth conduit connecting the first conduit to a portion of the fifth conduit between said rotary engine exhaust and said calibrated valve means and a non-return valve mounted in said sixth conduit for allowing hydraulic fluid to pass from said fifth conduit toward said first conduit.