Abstract: A piston and cylinder device wherein the piston comprises an annular metal core with a peripheral groove for receiving an annular seal. The metal core has a peripheral overlay of nylon which provides a bearing surface at each side of the peripheral groove and the overlay follows the contour of the periphery of the metal core including the walls of the peripheral seal receiving groove.

Abstract: A multiple element seal ring system comprising a pair of pressure non-deformable split rings and a deformable expander ring adapted to be received in a groove. The split rings are provided with relatively narrow inner surfaces spaced from the groove bottom wall to provide clearances of short axial extent therebetween for restricting deformation of the expander ring within its elastic limits.

Abstract: A hydraulic strut primarily for use in an off-highway vehicle suspension system having a pair of liquid springs connected together in tandem in axial alignment for providing two distinct spring constants to the suspension system. The spring constants are provided to operationally correspond to the loaded and unloaded condition of an off-highway vehicle such as large dump trucks and other similar equipment. Each liquid spring includes a cylinder filled with pressurized hydraulic fluid with a displacement rod reciprocably slidable in a sealed manner through one end of the cylinder means. The free ends of the two displacement rods are connected between the chassis and body portion of the vehicle to provide composite suspension afforded through the different spring constants. In addition, each liquid spring includes a dampening head attached to its respective displacement rod so as to provide spring suspension to the vehicle in a controlled and desired manner.