Abstract: In a double-tube vibration damper the cylinder engages by a terminal edge thereof an engagement face of a piston rod guiding and sealing unit. When the piston rod moves in the outward direction with respect to the cylinder, a high pressure occurs in the working chamber adjacent the piston rod guiding and sealing unit. Due to this high pressure damping liquid jets may escape between the terminal edge of the cylinder and the engagement face of the piston rod guiding and sealing unit. These liquid jets may cause foaming within the annular space defined between the cylinder and a container surrounding the cylinder. In view of avoiding such foaming, an annular cover member is provided between the cylinder and the container, which annular cover member prevents the direct entrance of liquid jets into the annular space between the cylinder and the container.

Abstract: A piston rod particularly for shock absorbers and spring devices has been shown in the illustrative embodiments. The piston rod comprises a tubular member which tubular member is provided with at least one extension of reduced diameter. The extension is intended for being fastened to associated structural members. In view of fluid-tightly closing the interior of the piston rods on at least one of their ends, a closure member is provided within the cavity defined by the extension of reduced diameter. The closure member is fastened to the piston rod by the reduction of the diameter of the piston rod.

Abstract: A hydropneumatic damping device particularly for spring legs of automotive vehicles comprises an inner cylinder, an outer container, a central cavity within the inner cylinder, an annular cavity between the inner cylinder and the outer container, a piston rod with a piston unit, venting passage means between the central cavity and the annular cavity extending across a cavity-closing unit and check valve means associated to said venting passage means. The check valve means comprises an annular check valve member in frictional sliding engagement with the piston rod for axial movement with the piston rod towards a sealing position during inward movement of the piston rod and towards an opening position during the outward movement of the piston rod. First and second abutment means are provided for defining the sealing and the opening position of the annular check valve member, respectively.

Abstract: In a shock absorber unit for vehicles of the double-tube type a piston rod guiding member is provided at respective first ends of a cylinder and a container surrounding the cylinder. The first end of the container engagingly surrounds a radially outer face of the piston rod guide member. The container is tube-shaped and has substantially constant wall thickness along its total length. The radially outer surface of the piston rod guiding member is provided with at least one radially inward directed recess or at least one radially outward directed projection. The first end of the container is deformed such as to engage this projection or recess respectively. A sleeve member engagingly surrounds the first end of the container. This sleeve member is also provided with a deformation which deformation is in engagement with the deformation of the container.

Abstract: A piston-cylinder unit for shock absorbers or the like is formed with a tubular container surrounding the cylinder and with a piston rod guide and sealing unit mounted at one end of the container with a support for the cylinder at the other end of the container. In order to effect a satisfactory sealing action at the fixing points of the cylinder, the cylinder is formed with a radial indentation.

Abstract: A shock absorber assembly including a cylinder having a piston and piston rod mechanism movable relative thereto is formed with a hydraulic-mechanical damping system interposed in an annular space defined between the piston rod and the cylinder. The damping characteristics of the system are varied in accordance with the relative movement of the piston rod out of the cylinder by a damping mechanism which includes a spring, an annular member and a damping component operating to vary the cross-sectional area of the damping passage defined therethrough.