Hydraulic shock absorber with two-way action

Claim 1

A hydraulic shock absorber with two-way action, with a pressure tube arranged in a housing and at least partially filled with hydraulic oil, and with a plurality of throttle openings which are distributed over the length of the pressure tube and connected on one hand to a pressure space of the pressure tube and on the other hand to cavities (12, 13, 14) radial gaps (28, 19) and axial gaps (26, 27) of the housing, with piston rod seals (38, 39) at the ends, characterized in that: (a) a pair of pistons (18, 19), each provided with a solid piston rod, (22, 23) are associated with the common pressure space (16) of the pressure tube (6); (b) the piston rod seals (38, 39) are at least nearly completely relieved of the pressure of pressure medium; (c) a compression return spring is mounted in said pressure space, between said pistons, and the ends thereof are seated against the respective adjacent piston; (d) each of said pistons has a channel means extended therethrough for connecting the respective adjacent radial cap at its end of the pressure tube with the pressure space (16) in the pressure tube; and; (e) each of the pistons has a check valve mounted in the channel means therein for normally closing off flow of hydraulic oil through said channel means during a shock absorbing movement of a piston inward of the pressure tube, and for allowing flow of hydraulic oil through said channel means from said cavities and gaps and back to said pressure space in the pressure tube during a retroactive outward movement of a piston in the pressure tube.