Patent ID: 7143875

Claim:
In a hydraulic damper having a cylinder, a piston movable in a reciprocating manner within said cylinder, hydraulic chambers provided at opposite sides of said piston, and an on-off control valve provided in a passage for connecting both said hydraulic chambers and being on-off controlled to change a damping coefficient, a damping coefficient switching-type hydraulic damper, characterized by providing a mechanical drive means, between a piston rod and said on-off control valve, said mechanical drive means structured so that a first damping coefficient is attained with said on-off control valve maintaining a closed state for movement of said piston in one direction, and a second damping coefficient is attained with said on-off control valve once opened at a time when the movement of said piston is turned in an opposite direction, and afterwards, is switched to the first damping coefficient with said on-off control valve closed again, said mechanical drive means being comprising a straight gear provided at the piston rod of said cylinder, and a crank mechanism that works with said straight gear to on-off control said on-off control valve.