Abstract: A hydropneumatic spring usable as steplessly blockable setting device comprises a by-pass connection in its piston. In this by-pass connection there is arranged a shut-off valve actuatable from the exterior. Furthermore the by-pass connection can be opened by excess pressure in each of the two working chambers. In this way the setting of length of the hydropneumatic spring can be altered by predetermined inward and/or outward thrust forces even when the shut-off valve is closed.

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 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.

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: In an arrangement of gas springs as weight counter-balance and retaining device for a part pivotable substantially about a horizontal axis such as a flap, lid or door, a simple construction is required which guarantees two stable open positions for the pivotable part. This is guaranteed in that two gas springs are arranged where the first of the two gas springs possesses an outward thrust force acting over the entire range of displacement of the pivotable part, while the second gas spring possesses an outward thrust force acting over a part of the displacement range and an additional force-free displacement range.

Abstract: A taper connection between a chair column and a seat plate is proposed. The external taper of the chair column adjoins a cylindrical section of the chair column. The internal taper of the seat plate, fitted together with the external taper of the chair column, protrudes beyond the transition between cylindrical section and external taper.

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: 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.

Abstract: 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.

Abstract: A gas spring particularly for jumping stilts comprises a working cylinder and a plunger. In the working cylinder there is a working chamber containing a mass of gas. A gas exchange chamber is fixed with respect to the working cylinder. An exchange passage connects the working chamber and the gas exchange chamber. A gas exchange valve is provided in the exchange passage. An exchange operating handle is provided separate from the plunger.

Abstract: In a cylinder piston device two working chambers on both sides of a piston are interconnected by a fluid passage. This fluid passage includes in series a first passage section and a second passage section. The first passage section comprises a first bore and a second bore in parallel. The first bore is always open. The second bore is opened and closed by a throttling valve body in response to the direction of axial movement of the piston. The second passage section is opened or closed selectively by a closure body controlled from outside the cylinder.

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: A fluid-operated actuating device of the type including an actuating cylinder member, an axially movable actuating piston rod member, and actuating fluid connection means for introducing actuating fluid to and removing actuating fluid from the actuating cylinder member so as to adjust the relative axial position of the actuating cylinder and piston members and including structure for damping the movement of the piston rod member with respect to the cylinder member.

Abstract: A shock absorber comprises a cylinder and a piston rod passing through at least one end of the cylinder. A piston unit is mounted on the piston rod and divides the cavity within the cylinder into two working chambers. A damping fluid is contained within the cylinder. The working chambers are interconnected across the piston unit by first and second branch flow passages arranged in parallel. First and second flow valves are associated with these first and second flow passages, respectively, and operate to dampen movement of the piston rod in at least one direction in dependency on the velocity of movement. The first branch passage flow valve is normally open and closes only when a predetermined velocity of movement is exceeded. The second branch passage flow valve is normally closed and opens only when the pressure differential between the working chambers exceeds a predetermined value. Closing of the first branch passage flow valve increases the 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: 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 for height adjustment of drawing-tables or the like includes an arrangement for hydraulically locking the gas spring against sudden collapse due to overloading or loss of internal gas pressure. The hydraulic locking mechanism includes a pressure responsive valve which operates, in response to an excess pressure differential between the gas spring cavity and the pressurized gas chamber, either to prevent flow of the hydraulic locking medium out of the cylinder cavity or to restrict such flow to a slow, safe rate.

Abstract: A piston for a pneumatic, hydraulic or hydropneumatic fluid-filled cylinder includes a constantly open throttled passage therethrough comprised by at least one spiral-shaped throttled channel extending in a plane perpendicular to the piston axis. The spiral configuration of the throttled channel permits the use of a relatively large flow cross section in the channel, thereby preventing clogging of the throttling passage by contaminants entrained in the damping medium, while still providing the desired 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.