Abstract: A pneumatic strut for use as an opening power assist mechanism for a motor vehicle tailgate has a piston rod extending from a piston contained within a cylinder. The piston separates the cylinder into two work chambers, each containing a gas charge under pressure. A bypass opening is active to connect the work chambers during the initial opening displacement of the tailgate to automatically open the tailgate through a first opening angle range. A second valve can be externally actuated to connect the two work chambers to further selectively open the tailgate into a second opening angle range. To close the tailgate, a third, directionally dependent valve can automatically connect the two work chambers during the closing displacement of the tailgate.

Abstract: According to an illustrative example of the invention, a gas spring is combined with a telescopic tube which is axially slidable on the cylinder of the gas spring. The piston rod and the telescopic tube are provided at the respective most remote ends thereof with fastening eyes. The telescopic tube can be fixed in a plurality of positions with respect to the cylinder. For such fixation, the cylinder is connected with a carrier within the telescopic tube between opposite end walls of the cylinder and the telescopic tube. A locking bolt is guided within the carrier in a direction transverse to the axis of the telescopic tube. The locking bolt is engageable with a corresponding plurality of openings in the telescopic tube. The locking bolt is biased by a spring into an engagement position with respect to a respective opening and can be released from such engagement by being inwardly pressed by an operator.

Abstract: According to an illustrative example of the invention, a gas spring is combined with a telescopic tube which is axially slidable on the cylinder of the gas spring. The piston rod and the telescopic tube are provided at the respective most remote ends thereof with fastening eyes. The telescopic tube can be fixed in a plurality of positions with respect to the cylinder. For such fixation, the cylinder is connected with a carrier within the telescopic tube between opposite end walls of the cylinder and the telescopic tube. A locking bolt is guided within the carrier in a direction transverse to the axis of the telescopic tube. This locking bolt is engageable with a corresponding plurality of openings of the telescopic tube. The locking bolt is biased by a spring into an engagement position with respect to a respective opening and can be released from such engagement by being inwardly pressed by an operator.

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 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 embodiment of the invention disclosed, a pressurized gas spring is arranged to provide three different damping-rate states as the piston rod is progressively urged axially outward of the cylinder. A first damping-rate stage is provided by an axially movable ring carried by the piston structure, a second stage is provided by an axially movable sleeve member slidably mounted on the piston rod for engagement at its inner end with the piston structure, and a third stage is provided by entry of the outer end of the sleeve member into a damping cylinder mounted adjacent the end wall of the cylinder through which the piston rod extends. The three damping-rate stages act cumulatively increasingly to slow outward movement of the piston rod.

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: 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: In the illustrative embodiments disclosed, an improved pressure-adjustment valve assembly for a pneumatic spring includes a valve channel connected at one end to the interior and at the other end to the exterior of the spring cylinder. The valve channel is preferably defined in part by a bore in an integral part of the cylinder and in part by a cap member removably mounted on such integral part. A valve body is axially movable within the valve channel between open and closed positions, coacting when in the closed position with a surrounding sealing ring to seal the cylinder against fluid leakage. The valve body is shaped to insure long seal lifetime. All components of the valve structure are designed and constructed to facilitate manufacture, use and assembly of the valve and to permit use of readily available materials.

Abstract: A gas spring includes a cylinder having two axial portions of different cross section and two pistons mounted on a common piston rod and respectively matching the cross sections of the cylinder portions. The pistons are spaced on the piston rod so that they are either both in the wider cylinder portion or respectively received in the two portions. A first throttling passage permits flow of fluid between the two cylinder compartments separated by the larger piston, and a second throttling passage by-passes the smaller piston only during movement inward of the smaller cylinder portion to permit flow of fluid out of that cylinder portion. A valve arrangement is biased for sealing the two parts of the cylinder cavity separated by the smaller piston when the latter is in the smaller cylinder portion, but does not move inward of that portion. The valve arrangement responds to a sufficient, axially applied force for connecting the two cavity parts.

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: A pneumatic spring conductively connecting a heater on the window pane in the tail gate of a station wagon to a battery is mounted between ball-and-socket joints whose plastic socket parts are equipped with barbs permitting insertion of the ball part without tools, but preventing accidental release.

Abstract: The pneumatic spring which holds the rear gate of a station wagon in the open position transmits electric current to heating filaments in the window of the rear gate by way of terminals on the piston rod and the cylinder of the spring, the terminals being connected by a contact spring in the cylinder cavity in the closed position of the rear gate.