Spring suspension system for vehicles provided with automatic load compensation

Claim 1

A resilient suspension system for wheeled vehicles having a chassis and provided with automatic load compensation means including a compression spring operably connected with a wheel axle or guide rail and operably related to the chassis via a piston-cylinder unit including a fixed component secured to the chassis and a moving component together with a liquid cushion of variable size within a pressure space of the piston-cylinder unit with such pressure space being so connected in dependence on load variations by means of a level-regulating device either with a source of pressure or a drain at the distance between the chassis and wheel axle or guide rail is set to a predetermined value, in which the improvement comprises said level-regulating device including a slide means, said fixed component having a head in which said slide means is slidably mounted, said slide means having an end face projecting into the pressure space and being admitted therein by the pressure in the pressure space and a spring bearing against the movable component, said slide means having an opposite eNd face subjected to the action of a constant lower atmospheric pressure and a further spring tending to displace the slide means to a position in which it provides communication between the pressure space and the drain and said first-named spring in conjunction with the pressure in the pressure space tending to displace said slide means into a position in which said pressure space is connected with the source of pressure.