Shock absorber, piston and valve structure

Claim 1

In a shock absorber including a cylinder having a chamber containing a shock absorbing medium, a piston assembly comprising a piston attached to a piston rod end, said piston assembly having a rearward side and a forward side, said piston rod attached to said rearward side of said piston assembly, a hub portion integrally attached with said piston assembly and extending forwardly from said rearward side, a plurality of circumferentially spaced axial openings in said piston, an annular valve plate axially slideable on said hub portion, a plurality of circumferentially spaced axial apertures in said plate, said valve plate has a rearward facing annular channel in its rearward side connecting said apertures together to evenly distribute the pressure of shock absorbing medium compressed between said openings, the width of said channel being greater than the diameter of said apertures but less than the diameter of said axial openings, means for limiting the rearward movement of said valve plate relative to said hub, said valve plate moving against said forward side of said piston during forward movement of said piston to cover said openings except for the areas thereof aligned opposite said apertures, the total crosssectional area of said openings in said piston being greater than the total aligned cross-sectional area of said openings after said valve plate engages said hub thereby producing a throttling effect, and said valve plate moving away from said forward side of said piston during rearward movement of said piston to uncover said openings and effect more rapid return movement of said piston.