Piston valve assembly for a shock absorber

Claim 1

A shock absorber piston construction comprising, a piston body having means thereon connected to one end of an associated piston rod, said piston body being formed with first and second sets of axially extending, circumferentially spaced flow ports, said first set of flow ports being greater in number than said second set of flow ports and said second set of flow ports being spaced radially outwardly from said first set of flow ports, a first annular axially extending valve seat being coaxial with said body on one side thereof adjacent said first set of flow ports, a first valve member engageable with said first valve seat to block fluid flow through said first set of flow ports, a plurality of circumferentially spaced valve seats on the opposite side of said piston body, said plurality of valve seats defining radial flow paths therebetween which are communicable with said first set of flow ports, said valve seats defining individual chambers at the ends of said second set of flow ports, each of said chambers being larger in cross-sectional area than the associated flow port terminating therein, with the sum of the cross-sectional areas of said chambers being of a predetermined ratio with respect to the sum of the cross-sectional areas of said second set of flow ports, a second valve member in the form of a flat annular valve disc extending radially of said body directly adjacent said plurality of valve seats and engageable therewith to block fluid flow through said second set of flow ports, said second valve member being movable between a first position permitting a first magnitude of fluid flow through said second set of flow ports and a second position permitting a second magnitude of fluid flow through said second set of flow ports, and at least one spring disc disposed on the axially opposite side of said second valve member from said piston body for resisting movement of said second valve member from said first position toward said second position.