Abstract: Hydro-pneumatic shock absorber of the kind comprising a fluid-containing cylinder which is divided into two chambers of variable volume by a piston mounted on a piston rod, there being also provided a compensation chamber for displaced fluid, a compressed gas pressure being maintained within said compensation chamber, wherein the aforesaid piston is secured to the middle of the piston rod which projects through a gland at each end of the cylinder, at least one of said two chambers of variable volume communicating with said compensation chamber by means of a communication port.

Abstract: A process for manufacturing highly wear-resistant, undistorted, axially symmetrical parts formed of a hardenable metal wherein the parts are subjected, in succession and while being rotated, to a surface pressure polishing process and to a surface hardening process without any further treatment.

Abstract: A shock-absorber piston of the kind having diametrically opposed valve ports which are adapted to be obturated by a resilient valve plate which can be deflected to an open position against a supporting plate. The valve plate and supporting plate are at least partly accommodated within a groove formed in an axial end face of the piston. The groove extends across the whole diameter of the piston and the inner face of the supporting plate is accommodated wholly within said groove.