Abstract: In a gas spring, the piston rod extends through one end of a container. Sealing rings are provided at this end of the container. These sealing rings are in sealing engagement with the piston rod and possibly also in sealing engagement with the inner surface of the container. Axially subsequent sealing rings are made of different caoutchouc materials. These different caoutchouc materials have different coefficients of permeation.

Abstract: In a gas spring the piston rod is guided through one end of a container. Adjacent to this one end two sealings are provided in axial direction one behind the other, namely an axially outer sealing and an axially inner sealing. A liquid chamber is defined between the axially outer sealing and the axially inner sealing. The axially inner sealing comprises a sealing ring of elastomeric material. This sealing ring comprises a radially outer root portion and a radially inner lip portion. The root portion engages an internal circumferential surface of the container tube. The lip portion engages an external circumferential surface of the piston rod. The axial dimension of the root portion is substantially larger than the axial dimension of the lip portion. The sealing ring may be deflected by pressure differences on both sides of the sealing ring such that a fluid exchange is possible between both axial sides of the sealing ring when the pressure difference exceeds a predetermined value.

Abstract: 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.

Abstract: In the illustrative embodiment of the invention as described an engine bonnet is articulated to the framework of a motor car. A gas spring is articulated to both the framework and the bonnet. The gas spring balances part of the weight of the bonnet when the bonnet is to be opened by hand. In case of an accident the framework and/or the bonnet may be crushed in longitudinal direction of the car. In such case the piston rod of the gas spring is pushed inward of the cylinder beyond the normal innermost operational position and a retaining device becomes effective so as to prevent the piston rod from returning towards its outermost operational position.

Abstract: A continuously adjustable levelling column for chairs comprises a guide tube having a lower end and an upper end. A telescopic tube is guided within the guide tube and has a tapered upper end portion extending beyond the upper end of the guide tube. A gas spring is accommodated within the telescopic tube. This gas spring is axially fixed within the telescopic tube. The upper end of a container of the gas spring abuts through a distance piece a support face at the upper end of the tapered portion of the telescopic tube. A piston rod passing through the lower end of the gas spring is axially fixed with respect to the lower end of the guide tube. A locking control pin extends through the upper end of the gas spring and is engageable through a transmission pin by a control handle.

Abstract: In a steplessly adjustable hydropneumatic device the spring chamber of which is arranged at the piston rod exit end and which works with a liquid locking, a very simple hydraulic locking is obtained even for high traction stressing upon the piston rod in that both an annular separator piston and the partition are arranged in the inner chamber of the container, which is penetrated by the piston rod. For the hydraulic traction locking in the case of traction forces exerted suddenly upon the piston rod a valve device is provided which cooperates with the piston rod.

Abstract: For a temperature-compensated gas spring, which consists of a container in which a concentrically arranged cylinder is arranged, where a main pressure chamber is separated in sealing manner from an auxiliary pressure chamber by a piston which is connected with a piston rod, a damping arrangement is provided for controlling the outward thrust speed. This is effected in that a damping chamber is arranged in which a damping piston provided with damping valves slides, the damping piston being arranged on an auxiliary piston rod which is in axially fixed connection with the piston rod.

Abstract: A flap member, e.g. a trunk lid of a motor vehicle, is pivotally mounted on a framework, e.g. a motorcar framework. The flap member is assisted in its upward movement by a gas spring. The thrust of the gas spring biases the flap member towards an upper position. In this upper position further upward movement of the flap member is locked by a relief pressure valve between the working chambers of the gas spring. By applying external force to the flap member assisting the thrust of the gas spring, the flap member may be moved beyond said upper position while opening said relief pressure valve. If the external upward directed force ceases the relief pressure valve closes again and the flap member is maintained in the new position by the thrust of the gas spring and the locking action of the relief pressure valve. When the flap member is to be lowered, an external force is applied opposite to the trunk lid and as a result thereof a direction-responsive is opened in parallel to the relief pressure valve.

Abstract: In the illustrative embodiments of the invention disclosed, the piston unit of a gas spring incorporates a meander-shaped fluid passage for interconnecting the working chambers on either side of the piston unit so as to dampen movement of the piston rod relative to the cylinder. The meander-shaped passages may be constituted by a sequence of passage sections arranged at right angles to one another and, in one embodiment, are formed in the end faces of the piston member so as to lie in planes transverse to the axis of the cylinder. If desired, additional fluid passage units may be connected in series to provide an enhanced damping effect.

Abstract: In the illustrative embodiments of the invention disclosed, the piston unit of a gas spring incorporates a meander-shaped fluid passage for interconnecting the working chambers on either side of the piston unit so as to dampen movement of the piston rod relative to the cylinder. The meander-shaped passages may be constituted by a sequence of passage sections arranged at right angles to one another and, in one embodiment, are formed in the end faces of the piston member so as to lie in planes transverse to the axis of the cylinder. If desired, additional fluid passage units may be connected in series to provide an enhanced damping effect.

Abstract: A gas spring arrangement in which conductive terminals on the cylinder and piston rod of a gas spring are connected by a conductive path insulated from the cylinder and piston rod. The path may be provided in part by contact elements on the cylinder and piston rod outside the cylinder cavity which engage each other when the piston rod approaches its axially terminal position during inward movement into the cavity. The path may also be provided in part by an insulated conductor helically wound on the piston rod in the cavity or outside. It may also include an axially elongated conductor secured to the axial cylinder wall outside the cavity.

Abstract: A gas spring of the piston-and-cylinder type in which the two compartments of the cylinder cavity, separated by a piston assembly, are connected by a first passage. A valve arrangement on the piston assembly defines a second passage between the compartments and closes in response to movement of the piston assembly away from a terminal position in the cylinder while opening in response to movement of the piston assembly towards the terminal position. Releasable locking structure carried in part by the cylinder and in part by the piston assembly cooperates to close the first passage when the piston assembly approaches the terminal position, thereby to hold the piston assembly in such terminal position.

Abstract: A gas spring arrangement in which conductive terminals on the cylinder and piston rod of a gas spring are connected by a conductive path insulated from the cylinder and piston rod. The path may be provided in part by contact elements on the cylinder and piston rod outside the cylinder cavity which engage each other when the piston rod approaches its axially terminal position during inward movement into the cavity. The path may also be provided in part by an insulated conductor helically wound on the piston rod in the cavity or outside. It may also include an axially elongated conductor secured to the axial cylinder wall outside the cavity.

Abstract: In the illustrative embodiments of the invention described, a pneumatic cylinder-and-piston device includes a unitary piston structure for providing two different damping rates in dependency on the direction of movement of the piston within the cylinder. Fluid flow across the piston is preferably controlled, to effect the different damping rates, by use of an elastic sleeve which at one end is carried by the piston and which at the other end engages, suitably under fluid pressure, the inner surface of the cylinder.

Abstract: A gas spring in which a valve permits flow of a pressurized fluid between two compartments of a cylinder cavity separated by a piston for movement of a piston rod attached to the piston outward of the cavity while inward movement of the piston rod is normally blocked by a mechanism which responds to a predetermined, axial, inward force applied to the piston rod for releasing the same.

Abstract: In the illustrative embodiment of a current-carrying pneumatic spring disclosed, flow of electric current between external terminals on the cylinder member and piston rod member of the spring is provided by a contact element fixed on one of the members and carrying one or more contact faces which are resiliently biased into sliding engagement with an axially elongated face portion of the other member. Flow of electric current between the external terminals may thereby be provided over a range of positions or over all positions of axial movement of the piston rod member inward and outward of the cylinder cavity.

Abstract: The tail gate of a station wagon carries an electric lamp for automatically illuminating the adjacent portion of the body compartment when the tail gate is open. The lamp is energized from the battery of the vehicle through a pneumatic spring which biases the tail gate toward the open position. The two fastening eyes of the spring insulate the piston rod and cylinder of the spring from the tail gate and body of the vehicle respectively. A switch sealed in the spring conductively connects the piston rod and cylinder, otherwise insulated from each other, when the spring holds the tail gate open, terminals on the piston rod and cylinder outside the cylinder cavity being connected to the battery and the lamp respectively.

Abstract: The piston in a gas spring of the piston-and-cylinder type is prevented from moving from one of its terminal positions under the pressure of the gas in the cylinder by a plunger on the piston projecting toward the closed cylinder end and received in an axial recess of a brake member on the cylinder by cooperating engagement elements on the plunger and brake member which may provide a friction fit or impede fluid flow into the recess.

Abstract: The cylinder cavity of a pneumatic suspension element of the piston-and-cylinder type in which the escape of compressed gas from the cylinder cavity is prevented by a liquid in a portion of the cylinder cavity through which the piston rod passes is charged with compressed gas and liquid through resiliently sealed gaps about the piston rod and/or through a porous partition separating the liquid-filled cavity portion from the gas-filled portion.

Abstract: The height of a chair and the inclination of its back support may be varied by changing the respective, effective lengths of two pneumatic springs whose assembly forms the chair leg. The cylinder of one spring is coaxially received in the cylinder or the hollow piston rod of the other spring, and relative axial movement of the received spring and the receiving element of the other spring is limited or entirely prevented. A valve connects the two compartments separated in the cylinder of each spring and may be operated by a mechanism separate from the valve operating mechanism of the other spring.