Damping device in pressurized fluid cylinders

Claim 1

In a hydraulic cylinder having a reciprocable piston, an arrangement for end position damping of the piston stroke, comprising a closure member connected to the piston and adapted to enter, during a damping process, into an outlet opening in front of the piston, and a ring serving as a non-return valve and arranged in an annular groove in a wall defining the outlet opening so as to prevent the flow of hydraulic liquid through an annular passage between the wall defining the outlet opening and the closure member during entry of said closure member into said outlet opening, while permitting a hydraulic liquid flow in the opposite direction during the return stroke of the piston, said groove having two axially spaced side walls, and said ring being made in one piece and having a substantially C-shaped cross-section so as to permit a resilient radial deformation, the radially inner portion of said ring being undivided circumferentially and the radially outer portion of said ring being provided with circumferentially distributed by-pass openings, and said ring being axially movable in said groove, whereby during the damping process an intermediate portion of said ring is in contact with one of said side walls to prevent the flow of hydraulic liquid through said passage and the radially outer portion of the ring is in contact with the other of said side walls during the return stroke of the piston so as to permit said hydraulic liquid flow substantially axially in said annular passage and said groove.