Abstract: A hydraulic damper is provided with a damping force adjusting mechanism. The damper includes a piston slidably positioned with a closed ended cylinder which functions to divide the interior of the cylinder into two chambers. Communication between the two chambers is provided by passageways partially defined by apertures and bores within the piston. Fluid flow between the two chambers via the passageways serves as the damping force. The damping force is made adjustable by a rotary valve positioned within one of the passageways which functions to vary the effective cross-sectional area of that passageway thus functioning as a damping force adjusting element. A device is provided to vary the damping force adjusting mechanism from the exterior of the hydraulic damper in accordance with a predetermined damping force.

Abstract: A vehicle height adjusting apparatus in which a sensor means detects the distance between the body and axles of a vehicle while the vehicle is parked or moving. A signal comparator divides the vehicle height detection range into a plurality of detection zones based on the sensor signals; a pulse converter circuit converts the signals into pulse signals of the detection zones; an integrator circuit integrates the pulse signals for a period of time; a determination circuit determines the vehicle height level and a fluid circuit controls the inflow and outflow of fluid into and out of a suspension device.