Abstract: A stop valve device (36) mounted in the by-pass (32, 36) of a vibration damper between a high pressure part section (32) and a low pressure part section (32a) has a stop valve (38) which can be moved by an external control (46) into an opening preparation state in which the actual opening can be brought about in dependence upon the pressure prevailing in the high pressure part section when the pressure falls below a predetermined value

Abstract: For a double-tube vibration damper which comprises an axially proceeding groove in the cylinder for by-passing the piston valves, a piston is provided which possesses a satisfactory sealing and guidance function in the cylinder. This is achieved in that the piston comprises a rigid piston ring arranged in a piston groove and acting as sealing ring against the cylindrical surface, while the piston comprises a second piston ring groove for the reception of a guide ring consisting of a piston ferrule. In this case at least one relief passage is provided which connects the second piston ring groove and/or the space situated between the piston ring grooves with the working chamber remote from the piston rod.

Abstract: In gas springs, shock absorbers and the like, the cylinder member may be provided with an interconnection groove on its internal face. This groove is to interconnect two working chambers on both sides of a piston member movably received within the cylinder member. This interconnection groove is produced by a roller member introduced into the cavity of the cylinder member and having an axis substantially perpendicular to the axis of the cylinder member. The roller member has an annular elevation on its circumferential surface which is to engage the internal face of the cylinder member. A support face profiled according to the profile of the external face of the cylinder member is brought into contact with the external face of the cylinder member. The elevation of the roller member is angularly aligned with a metal receiving groove of the support face.

Abstract: A cross-flow controlling valve for a hydropneumatic vehicle suspension has a casing formed with three ports of which two communicate with longitudinally terminal portions of a bore in the casing. A piston is freely slidable in the bore between two terminal positions. Longitudinally spaced shoulder portions of the bore bound a transversely open, longitudinal groove in the piston which is longer than the intermediate portion of the casing bore connecting the terminal bore portions. Each shoulder portion is dimensioned to bound a throttling gap connecting the groove with one of the terminal bore portions when the shoulder portion is received in the intermediate bore portion. The groove in the piston permanently communicates with the third casing port.