TWO-STAGE POWER HYDRAULIC CYLINDER Russian patent published in 2003 - IPC

FIELD: power hydraulic equipment and presses. SUBSTANCE: proposed hydraulic cylinder has common housing divided into two chambers by means of transversal partition; first-stage piston with rod is arranged in first chamber and second-stage piston with rod-plunger is arranged in second chamber forming hydraulic cavity in each chamber; rod-plunger of second-stage piston is mounted in central through hole found in transversal partition; hydraulic cavities of chambers are communicated with hydraulic pressure source through passages; passage connecting hydraulic pressure source with first-stage hydraulic cavity is provided with check valve; passage used for connecting the hydraulic pressure source with first-stage hydraulic cavity is made in form of cylindrical pipe union whose inlet end is rigidly secured in cover of housing; rod- plunger of second-stage piston is tubular; second-stage piston body has central hole; cylindrical pipe union is sliding fit in central hole and second-stage tubular rod-plunger; check valve is mounted in tubular rod- plunger of second-stage piston for engagement with end face of outlet end of cylindrical pipe union and seat surface made in final section of tubular rod-plunger; end face of cylindrical pipe union has through radial slots. EFFECT: enhanced reliability. 6 dwg