Abstract: A longitudinally controllable adjustment device, in particular a gas spring partially filled with a fluid has a piston disposed on a piston rod. In order to achieve simple manufacture and assembly and high operational safety, a valve housing for receiving a valve is provided on the piston rod. Further, the piston axially covers to total valve. The piston is secured to the piston rod by deformation, which simultaneously results in a pre-stressing of a seal sealing in four directions. The piston rod with the valve is compressed against a seal in the piston, which seal sealingly abuts on an annular bottom of a receptacle, on the receptacle, on the valve and on the valve body.

Abstract: A gas spring has a cylindrical housing and a piston rod mounted coaxially within it and sealingly extended out of same. The piston rod has a tapering cooperating with a seal in its pushed-in position. The seal is designed to be radially resilient and has an axially-operating radially resilient supporting ring which has webs extending parallel with the axis elastically movable radially to the axis, against which the seal applies. The purpose of this design lies in reducing the thrust force of the gas spring when the piston rod is pushed in, which should result at the same time in a reliable sealing in all operational positions.

Abstract: A lockable elevating mechanism for the continuous adjustment of chair seats or the like comprises a guide tube, in which a length-adjustable, lockable gas spring is slidably guided. The piston rod of the gas spring is connected to the bottom plate of the guide tube. The housing of the gas spring is guided by means of a guide sleeve in the guide tube, the guide sleeve having a central carrying tube, in which slide sleeves are arranged with space. The carrying tube is surrounded by a carrying sleeve held in the guide tube. Thus a gas spring is obtained, on the one hand, which is free of bracing, resistant to wear and with good sliding qualities, and, on the other hand, the manufacturing of the guide sleeve is favorable in terms of material expenditure.

Abstract: A gas spring substantially comprises a cylindrical housing, closed on one end, and a piston rod located concentrically in it and extending in a sealed manner from its other end, the piston rod being provided on its end located in the housing with a piston assembly resting on the inner wall of the housing and being guided in a damped manner. In order to attain a relatively broad hysteresis, which is desirable when the gas spring is used for retaining the upper parts of sun-tanning benches or automobile hatchbacks or the like, the piston assembly has a friction damping liner resting against the inner wall of the housing and made of an expanded plastic, which is open-celled and impregnated with lubricant on its friction face resting on the inner wall.

Abstract: A piston for a piston cylinder unit, particularly a gas spring, is to be provided with a piston ring and comprises a portion extending at least from the piston ring groove to a free end and consisting of a plurality of segments separated from one another by longitudinal slots. This portion is provided with a bore the diameter of which is at the free end smaller than the diameter of the related portion of the piston rod. It is the purpose of these measures to enable simple assembly of the piston ring in the piston ring groove and at the same time to ensure reliable seating of the piston ring.

Abstract: A fluid-filled piston-cylinder unit with a tubular fluid-filled housing closed at one end and with a piston rod emerging from the other end comprising, for guiding the said piston rod, a guide bush which is sealed on the one hand against the inside wall of the housing and on the other against the piston rod by the use of seals. Provided at the inner end of the piston rod there is a guide piston. In order on the one hand to avoid surface pressure between the piston rod and the guide bush and on the other to achieve an adequate length of guidance for the piston rod itself, the guide bush is provided with at least one spacer extending in axially parallel manner beyond the seals and in the direction of the guide piston and the cross-section of which is substantially smaller than the cross-section of the guide bush.

Abstract: A gas spring adjustable in length has a housing and a piston rod brought out at one end. Disposed at the opposite end is a valve by means of which movements of longitudinal adjustment of the piston rod relative to a housing filled with a pressure medium are released or stopped. These gas springs are principally used for the vertical adjustment of chairs or tables. In order to make said vertical adjustment more comfortable, a damper valve is disposed in the valve effecting in different manner in each instance the throttling on the insertion of the piston rod into the housing or on the extraction of said piston rod out of the housing.

Abstract: A gas spring with end positions damping has a cylindrical housing filled with a fluid under pressure, in which a piston rod, sealingly extending from one end of the housing, is disposed to be coaxially slideable and on the inner end of which a piston is attached. To create an end position damping that is simple in structure, and which can be used purely pneumatic, purely hydraulic or hydropneumatic, an auxiliary piston in the form of a throttle piston is slidingly disposed on the piston rod, which is supported via an energy accumulator towards the end of the housing where the piston rod exits. The piston abuts against this auxiliary piston at the end of the extension movement of the piston rod. Its throttle effect is larger during movement in the direction toward the end where the piston rod exits than in the opposite direction.

Abstract: An adjustable-length gas spring has a compressed gas-filled housing in which a piston with a piston rod is sealingly guided. At one end of the housing is provided a valve with a valve pin for connecting or separating two housing chambers, the valve pin being movable into the housing against the force exerted thereon by the gas pressure with the valve in the open position. The pin is movable against such force when the valve is in the closed position. There is also a permanent release mechanism for securing the valve pin when the valve is in the open position. In order to permit a particularly simple operation of the gas spring, the permanent release mechanism is formed by a bi-stable locking mechanism constructed in the manner of a mechanical flip-flop and which is coupled to the valve pin, being operated by the insertion thereof into the housing.

Abstract: A frictional damper, includes a circular-cylindrical casing and a ram which is coaxially displaceable in the casing and the inner end of which is provided with a cylindrical friction piston. On its external face, the friction piston is provided with one or more friction elements which are elastically pressed against the inner wall of the casing. To obtain a uniform surface pressure over the entire friction surface of the friction element or elements during the entire life of the frictional damper, the friction piston is provided with a bushing having a circular-cylindrical external shape and of counter-holder flanges or disks which project radially from the bushing and delimit the latter at a fixed axial extent. Moreover, at least one annular-cylindrical friction sleeve which has a closed circumference, is made of an elastically yielding material and is under tension in its inner circumferential zone, is provided on the bushing.

Abstract: A friction damper, especially for washing machines with a spin cycle, consists of a housing (1) having a substantially circular cylindrical inner wall and a tappet (2) that can be pushed coaxially into the housing, extending at one end out of the housing and at the other end being provided with a friction piston. The friction piston is provided with friction elements pressed elastically against the inner wall of the housing (1), and securing elements (4, 8) are formed on the respective ends of the tappet (2) and housing (1). To attain a considerable reduction in the damping forces once there has been a passage through the critical rpm level, the housing (1) is made of plastic.

Abstract: An adjustable-length gas spring has two compressed-gas-filled cylinders concentrically surrounding one another, with a piston and piston rod disposed in the inner cylinder thereof. A valve for effecting communication between housing chambers divided by the piston is provided at one end of the cylinders. This valve has a valve body, which is sealed with respect to the cylinders by means of outer ring seals.

Abstract: A height-adjustable office chair having an incline-adjustable seat and back includes a bearing device to which is connected a length-adjustable seat pneumatic spring connected by an articulated joint to the seat structure, a length-adjustable back-rest pneumatic spring connected to the back by an articulated joint, and a height-adjustable pneumatic spring. The actuating rods of all three of these pneumatic springs are in the bearing device and are controlled by an actuating lever movable both horizontally and vertically. Vertical movement of the actuating lever controls the height-adjustable pneumatic spring. Horizontal movement of the actuating lever serves to control one of two intermediate levers which are respectively arrestable and lockable by a detent lever located above the height-adjustable pneumatic spring.

Abstract: A lengthwise adjustable gas spring consists of a housing containing gas under pressure, which is formed by an outer tube 2 and a coaxially disposed inner tube 3 with an annular channel 4 therebetween. A closed piston 5 sealed against the inner tube and axially movable within same, is connected to a piston rod 9, which extends through a seal formed by a plug 10 at one end of the housing. A valve 23 is disposed at the other end of the housing and is used for the regulated connection via the annular channel 4 of two partial housing chambers 20a and 20b disposed on either side of the piston within the inner area of the housing. A valve lifter 22 is embodied within the valve body and is sealed against the valve body and opens or closes gas transfer ports. The valve body 23 and the plug 10 are axially supported against the inner tube 3 and are sealed against the inner surface of the outer tube 2. In order to avoid use of separate seals, the valve body e.g.

Abstract: A pneumatic spring for use, for example, as a lifting device or support strut for a chair or the like with provision for the adjustment of axial extent. The pneumatic spring is substantially composed of a telescoping cylinder-piston assembly containing a gas and/or fluid under compression. A releasable valve assembly permits the relative position of the piston with respect to the housing to be adjusted arbitrarily. In order to provide for a terminal spring stiffening in the position of near full insertion of the piston rod, the invention provides that a pin extending from the main piston enters a central volume which is thereby sealed off from the remainder of the internal volume. Accordingly, the gas in the remaining available volume is compressed more highly and exerts an increased opposing force on the primary piston during its final insertion.

Abstract: A securing device for releasably attaching the columns or legs of chairs, tables and the like. The securing device is fixedly mounted to the underside of the chair seat or table top and includes a receiver in which the column or leg is inserted. A gripper shoe can be advanced radially against the column to hold it in place. The radial displacement of the gripper shoe is caused by the force exerted by an eccentric stack of discs of different size which are assembled into an integral body that is rotated about an axis, thereby forcing the larger eccentric discs into camming engagement with mating extensions of the gripper shoe. Upon release of the eccentric, the column may be pushed out of its receiver by the upward motion of a handle which pivots about a ball joint resting on the eccentric body and exerts an axial downward force on the column to be removed.

Abstract: A gas spring suitable as a lifting means for a car hatchback includes a device to hold the gas spring piston rod in its extended position with the hatchback fully open. Such holding device comprises a pair of check valves associated with the guide piston of the gas spring whereby one such check valve is spring-biased closed so that a substantial closing force is required to initiate closing of the hatchback.

Abstract: A height-adjustable chair or table pedestal having a hydraulically lifting cylinder and a piston rod telescopically extending therefrom is characterized by having the lower end of the piston rod mounted in the base of the device, with an energy source, hydraulic pump means and a lifting mechanism mounted as a sub-assembly out of view on the underface of the chair or table.

Abstract: A length-adjustable gas spring is provided with a by-pass valve comprising a piston sealing element and a depression in the inner tube of the gas spring so that when the piston sealing element is pushed to a position adjacent the depression, the valve is opened.

Abstract: A gas spring, particularly adapted as a lifting means for hatch backs or trunk lids of motor vehicles, comprises a piston rod acting as a displacement piston, a housing cylinder containing a compressed gas, a guide piston near one end of the piston rod and in slidable relationship with the interior of the cylinder housing, characterized in that the piston rod is provided with an extension projecting beyond the guide piston, the closed end of the cylinder housing having a complementary receptacle for the piston rod extension, whereby when the piston rod is fully retracted into the cylinder housing, the extension enters the complementary space in the housing in a sealing manner, a valve being provided to permit the escape of fluid from the space as the extension passes thereinto, whereby the force acting to extend the piston rod is reduced to zero or nearly zero in the vicinity of the fully retracted position of the piston rod.