Abstract: In the illustrative embodiments of the invention disclosed, the extension rce of a gas spring is controlled as a function of temperature by varying the volume of the working chamber entered by the piston rod, and thus the gas pressure within the working chamber, as a function of temperature.

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: In the illustrative embodiments of the invention described, a main gas spring unit used to raise and lower a movable leg rest member of a bed construction includes a further gas spring device axially connected end-to-end to the main gas spring unit. The addition of the gas spring device allows the leg rest member to be raised, with only a small manual effort, to a higher level than is possible with the main gas spring unit alone. Preferably the internal force exerted on the piston rod of the main gas spring unit is greater than the internal force exerted on the piston rod of the gas spring device. The cylinder members of the main gas spring unit and the gas spring device may be formed by a common tubular member, with the two units being separated by a common movable wall. Alternatively, the cylinder members can be separate self-contained members that are rigidly attached at adjoining end walls thereof.

Abstract: In the illustrative embodiments of the invention described, a pressurized fluid device of the cylinder and piston rod type includes, at one end thereof, an elastomeric closure member which is movable, under the force of the fluid to be introduced into the device, away from a sealing position with respect to the cylinder, and piston rod to a position in which the fluid is admitted into the cylinder for purposes of charging the same. Upon completion of the charging, or fluid-filling, step the closure member is returned to the sealing position either by movement of the piston rod alone or in conjunction with the action of the fluid pressure within the cylinder.

Abstract: In the illustrative embodiments described, a pneumatic spring includes selectively releasable structure, located in part at the outer end of the piston rod and in part at the corresponding end of the cylinder, for retaining the piston rod at or near its innermost position within the cylinder. The retaining structure carried by the cylinder preferably constitutes a sleeve surrounding the piston rod, and the structure carried by the piston rod may include projections for coacting with shoulders on the sleeve. Alternatively, the sleeve and piston rod may be formed with cooperating recesses for receipt of an external pin-like securing bracket.

Abstract: In the illustrative embodiments described, a cylinder-piston device such as a gas spring includes a novel piston rod-piston unit assembly which embodies a snap-on type construction for facilitating the connection and disconnection of the piston unit to and from the piston rod. Resilient tongue members carried by the piston unit are formed with detent-like abutment members at their free ends, which abutment members snap behind an engagement shoulder, formed for example by a disc or groove, on the piston rod to hold the piston unit on the rod. The free ends of the tongue members are also formed with bevelled surfaces which coact with the piston rod to cam the tongue members radially outward as the piston unit is urged onto the piston rod, so that the abutment members are first displaced away from and then snap behind the abutment shoulder.

Abstract: A pneumatic spring having a cylinder and a piston rod biased axially outward of the cylinder by compressed gas in the cylinder cavity may be stopped in an axially intermediate position of the rod by engagement of respective radial faces on an abutment member mounted on the rod for axial movement and on a rigid abutment member fixedly mounted on the cylinder and projecting into the normal axial path of the other abutment member which may be deflected manually from its normal path for release of the rod.

Abstract: A gas spring of the cylinder-and-piston type having a throttling passage in the piston has a cup-shaped receptacle coaxially mounted on the piston about the piston rod and a plunger mounted on the annular end wall of the cylinder through which the piston rod passes. The plunger enters the receptacle when the piston rod approaches the outer end of its stroke, and fluid can be displaced by the plunger from the receptacle only through a narrow gap between respective walls of the plunger and receptacle for supplemental damping action.