Hydraulic-Actuating Device for Motor Vehicles Patent, 1982
From the patent description: A hydraulic-actuating device for use in motor vehicles, whereby hydraulic actuators are positioned to replace conventional shock absorbers, the actuators being mounted between the frame structure of the vehicle and its associated wheel-suspension unit, wherein each hydraulic actuator includes a support or guide plate and a coil spring.
The actuator is arranged to be movably engaged with the vehicle frame structure by means of the coil spring member which is supported by the lower arm member of the vehicle-suspension unit of each wheel, the guide plate being interposed between the spring member and the rod of the actuator.