Rockshox, Inc.

Mike McAndrews

Paul H Turner

A shock absorbing fork for a bicycle or other two-wheeled vehicle of the type having a pair of telescoping struts, with upper tubes which are interconnected by an upper crown to a steerer tube at an upper end portion thereof and lower tubes which are which mount a wheel axle at a bottom end thereof. Within at least one of the telescoping struts a spring arrangement and/or a hydraulic damping arrangement is provided which is acted upon as the upper tube and the lower tube move toward each other for absorbing impact shocks experienced by the wheel of the bicycle. For shock absorbing forks in which no hydraulic damping arrangement is provided or it is contained within a separate cylinder or cartridge which isolates its hydraulic damping fluid from walls of the telescoping tubes, so that damping fluid cannot be used as a source of lubricant for the telescopic tubes, according to the invention, a predetermined free quantity of liquid lubricant is provided in the bottom of the lower tube in a volume that small enough so as not to be directly acted upon by the upper tube even during maximum (inward) compressive telescoping of the strut, but which is sufficient to migrate along the length of the lower tube without being directly acted upon by the reciprocating motion of the tubes relative to each other.

Fork suspension with oil bath lubrication

A front fork for bicycles which has a shock absorbing system having both a spring type shock absorbing unit and a hydraulic shock damping unit with variable and adjustable damping characteristics that will allow a wide range of adjustments for adapting the suspension to widely differing circumstances of rider weight and riding experience and has a spring type shock absorbing system which can be interchangeably be used with both stacked elastomeric pad and coil spring type spring shock absorbing units. Stacked elastomeric pad arrangements are provided which allow the pad stack to be exchanged as a unit with another pad stack or with a coil spring and an adjustment mechanism allows the performance characteristics of a particular pad stack to be changed. Alternatively, a leaf spring arrangement can be provided formed of pairs of oppositely facing convex-concave carbon fiber composite leaf springs can be employed to produce a unit that is especially light in weight. Furthermore, the spring unit, whether coil, pad, or leaf type, is able to co-act with the upper end of a piston rod of a hydraulic damping unit.

Bicycle fork suspension with exchangeable spring unit

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.

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Santa Cruz, CA, United States of America

Mike McAndrews