subject: An Adjustable Rebound Damping Shock Absorber [print this page] The present invention relates to a shock absorber which has a variable rebound damping assembly independent of a piston assembly for use with automobiles, off-road vehicles, racing vehicles and motorcycles.
Various piston-type fluid filled shock absorbers have included apparatus for adjusting or controllably varying the shock absorbers' damping characteristics or cushioning effects during compression or rebound of the shock absorber. When the vehicle's springs compress, as occurs when the vehicle wheels strike a roadway elevation, the pistons of the shock absorbers move in their compression stroke, downwardly in the cylinders of the shock absorbers. When the vehicle's springs expand, the pistons of the shock absorbers move in their rebound stroke, upwardly in the cylinders.
The greater the degree to which the flow of fluid within the rebound chamber or the compression chamber is restricted, the greater the damping forces which are provided by the shock absorber. Accordingly, when the flow of fluid is relatively unrestricted between the rebound chamber and the reservoir, a "soft" rebound stroke is produced. Likewise, when the flow of fluid is restricted between the rebound chamber and the reservoir, a "firm" rebound stroke is produced.
These valves unseat only after a predetermined fluid pressure builds up in the compression or rebound chambers which overcomes the spring load and are generally located in the piston or a piston assembly. These shock absorbers can be adjusted to increase or decrease the spring pressure on the valve seat, but requires the removal of the shock absorber from the vehicle, the collapsing of the shock absorber, rotation of the piston against a retaining mechanism and reinstallation of the shock absorber on the vehicle. Others require careful adjustment and securing of the mechanism.
A high degree of adjustability of the shock absorber is highly effective when the track or road conditions are predicable and when the mechanic making the adjustment is thoroughly familiar with the effects of the adjustment. However,it has been difficult to provide means for accurately adjusting the spring load acting on the valve without greatly increasing the cost of the shock absorber.
An adjustable damping shock absorber has a piston and cylinder type shock absorber that utilizes an externally controlled flow path between the rebound chamber and the reservoir. Fluid through the flow path is metered by a three-setting valve that interacts with three bores through an inner cylinder head which provide fluid communication between the reservoir and the rebound chamber.
