Fork suspension with variable hydraulic damping

Abstract

Shock absorbing fork, especially a front fork, for a two-wheeled vehicle, particularly a bicycle, of the type having a pair of telescoping struts and a hydraulically damped shock absorbing arrangement disposed within each of the telescoping struts, the shock absorbing arrangement having a piston which divides a hydraulic fluid containing cylinder into upper and lower chambers, a valve regulating flow of hydraulic fluid through the piston between the upper and lower chambers, and a piston rod connected to the piston. Among the improvements of the invention is the provision of a spring for absorbing shocks that acts on the piston of the hydraulic shock damping arrangement upon compression of the telescopic struts, and a location sensitive flow control arrangement having a flow path extending between opposite sides of said piston and a flow adjusting element which is displaceable into and out of said flow path as a function of the extent which the spring is compressed by compression of the telescopic struts. As a result, flow through the flow path is progressively changed as the struts are compressed and the damping characteristics of the hydraulic damping arrangement are progressively varied. Furthermore, a compression damping adjuster shaft having an axially adjustable abutment member thereon to hold the resilient pad against a spring disc of the compression valve of the piston under a holding pressure which is adjustable by axial displacement of the abutment member. Additionally, the entire hydraulically damped shock absorbing arrangement is formed as a self-contained replaceable cartridge unit.