Stabilus Gmbh

Martin Siemann

Herbert Freitag

Castor Fuhrmann

Hans-Josef Hosan

Helmut Morgen

Jürgen Kessler

Wolfgang Luhn

Manfred Zirbs

Willi Wildemann

A positioning device is e.g. used for positioning the door of a motor vehicle in an opened position. The positioning device comprises e.g. a cylinder and a piston rod which extends inward and outwards of the cylinder through one end thereof. A flank face is provided at the inner wall surface of the cylinder. The piston rod carries a piston. The piston is provided with a counter-arresting ring which engages the flank face in a predetermined position. When the piston passes across the arresting flank of the cylinder, the counter-arresting ring is moved radially inwards with respect to the axis of the piston rod against elastic resistence. So, an increased resistance occurs against the axial movement of the piston rod with respect to the cylinder. This increased resistance against axial movement positions the door with respect to the body frame of a motor vehicle in a predetermined opened position and avoids that the door is closed unintentionally. Af the flank face and the arresting ring are enclosed within the cavity of the cylinder, they are not subject to environmental conditions, which might deteriorate their positioning function after a period of use. Lubricating agent may be provided within the cavity for lubricating the flank face and the arresting ring. As such lubricating agent is enclosed within the cavity of the cylinder, there is no risk for the vehicle driver to be polluted by the lubricating agent.

Positioning device

In a hydraulic positioning device a piston divides the cavity within a cylinder into two working chambers. The piston is connected with a piston rod passing through one end of the device and with a volume compensating rod through the other end of the device. The piston rod is provided with a passage which can be opened and closed by a valve so as to allow optional adjustment and blocking of the piston rod. The hydraulic liquid within the working chambers is subjected to volume variation in response to varying temperatures. With the aim of compensating such volume variations a partition at one end of the cylinder is supported by an abutment of the cylinder through an axially deformable compensating body having preferably a deformation force--deformation path characteristic which is responsive to temperature.

Temperature-compensating hydraulic positioner

In a fluid-operated device such as a gas spring a piston rod is axially movably guided through a passage in an end wall of the gas spring. A sealing disc of elastomeric material is axially compressed between two supporting faces and engages the piston rod with a convex radially inner edge. The apex of the edge is substantially midway of the axial thickness of the sealing disc. Preferably the sealing disc has also a radially outwardly convex sealing edge which is in sealing engagement with a stationary face surrounding the sealing disc.

Seal for pneumatic, hydraulic or hydropneumatic units

Gas springs are frequently used for assisting the movement of a movable construction unit, e.g. a boot lid with respect to a stationary construction unit, e.g. a motor car frame. In view of facilitating the closing operation of the boot lid, the pressure in the gas spring is sometimes selected such that the gas spring cannot fully overcome the gravitational forces acting onto the boot lid. In such cases the gas spring cannot fulfill the function of maintaining the boot lid in the upper terminal, i.e. the fully opened position without additional provision. In order to enable the gas spring to maintain the boot lid in the upper terminal position, the gas spring is constructed such that in the outer terminal position of the piston rod with respect to the cylinder an increased resistance is exerted by the gas spring against pushing the piston rod inwards of the cylinder. A simple and economic hydraulic circuit is proposed in view of achieving such increased resistance.

Gas spring

In a pneumatic or hydropneumatic tension spring which consists of a container in which a cylinder is concentrically arranged and a liquid and/or gas filling under pressure has an inward force upon a piston rod, between a working chamber on the piston rod side and an annular chamber a damper device is arranged which generates a greater damping effect in the inward movement of the piston rod than in the outward movement of the piston rod. Due to this measure a damped inward movement of the piston rod is achieved while the extraction of the piston rod can be effected without appreciable damping.

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Bad Breisig, Germany

Martin Siemann