Abstract: A shock absorber includes the typical fluid valving in the piston and in the base valve assembly which is designed to provide a firm damping characteristic for the shock absorber. A stepper valve assembly includes a bypass fluid passage between the upper working chamber and the reserve chamber which when opened provides a soft damping characteristic during an extension movement of the shock absorber. The stepper valve assembly also includes a bypass fluid passage between the lower working chamber and the reserve chamber which when opened provides a soft damping characteristic during a compression movement of the shock absorber. The stepper valve assembly selectively opens and closes the bypass fluid passages to adapt the shock absorber to changing vehicle conditions.

Abstract: An adjustable damping shock absorber includes a pressure tube with a piston valve assembly slidably disposed within it. The piston valve assembly includes a compression valve assembly which is biased to a closed position and an extension valve assembly which is also biased to a closed position. The damping rate for the shock absorber is adjusted by selectively changing the biasing load of one or both of the valve assemblies. When the biasing load is increased, a firm damping for the shock absorber is produced. When the biasing load is decreased, a soft damping for the shock absorber is produced.