Shock absorber and suspension strut

Claim 1

A vibration damper mechanism comprising a cylinder having a predetermined quantity of hydraulic fluid sealed therein, an annular piston slidably mounted in the interior of said cylinder for dividing said cylinder into first and second variable volume chambers, a hollow piston rod having an open end secured to said annular piston and passing outwardly from said cylinder through said first chamber, stop means on said piston rod to limit outward movement of said piston rod from said cylinder, guide means for guiding said rod in sealed sliding engagement with an aperture in one end of said cylinder, the other end of said piston rod being closed to define a hydraulic fluid receiving chamber adjacent said open end and a gas chamber adjacent said other end, said hydraulic fluid receiving chamber in said hollow piston rod being disposed in permanent communication with said second chamber through the central opening in said annUlar piston to define a unified hydraulic fluid pressure chamber, a fluid flow limiting conduit means secured to said hollow piston rod and having an inlet end and an outlet end, said inlet end being disposed in communication with said first chamber adjacent said stop means between said stop means and said guide means and said outlet end being disposed in communication with the interior of said hollow piston rod, one way valve means for permitting restricted fluid flow from said unified chamber to said first chamber and one-way valve means secured to the outlet end of said conduit means to permit fluid passage from said first chamber to the interior of said hollow piston rod.