Abstract:
A piston assembly for a gas spring or damper includes first and second orifice plates that are axially spaced apart from each other. First and second low-friction rings are positioned between the first and second orifice plates. The first and second low-friction rings are separated from each other by a resilient member, which reacts between the first and second low-friction rings to eliminate dead-band operation as the piston assembly moves between extension and compression positions.
Abstract:
A pneumatic counterbalance spring includes a hollow cylinder defining a first internal chamber divided into a compression compartment and an extension compartment by a piston movably mounted in the chamber. The compression compartment contains pressurized gas and a seal assembly mounted on the piston prevents the gas from escaping into the extension compartmint. A piston rod is slibably mounted in the open end of the cylinder and has its inner end connected to the piston. The piston rod includes a hollow portion defining a second internal chamber which is fluidly connected to the compression compartment by a flow passage. As a result, the compression compartment has an effective volume of A+B, where A represents the volume of the compression compartment and B represents the volume of the piston rod internal chamber. This design is advantageous in applications where a low spring rate is desired and where the length of the spring needs to be minimized. A gas permeable insert may be positioned in the flow passage to provide restricted rate flow of gas through the flow passage. Alternatively, a check valve may be provided for providing restricted rate flow of gas through the flow passage during the extension stroke and a tree, by-pass flow of gas through the flow passage during the compression stroke.
Abstract:
A pneumatic spring counterbalance extensible link including a closed end cylinder with an end connector a piston and rod assembly within the cylinder and maintained therein by the crimped over end portion of the cylinder retaining a rod bushing and rod to cylinder seal. The cylinder is pressurized prior to assembly of the complete piston and rod into the cylinder. The piston assembly includes orifice by-pass arrangements either in the piston periphery or in a piston ring, and the piston may include a fail-safe provision in the event the orifice is clogged. A crimping die assembly is used in assembling and completing final assembly of the counterbalance components while simultaneously maintaining the link in a pressurized environment, utilizing sealed arrangement between the crimping dies to maintain pressurization of the interior of the dies and the counterbalance components prior to assembly of the components. A dual force embodiment of the counterbalance unit is disclosed and utilizes a floating sealed piston below the main piston and rod assembly entrapping pre-charged gas in the space between the floating piston and the closed end of the cylinder.
Abstract:
A gas spring and a retractable device cooperate to provide a two-way assist mechanism for controlling movement of a body panel. The retractable device includes a spring assembly received within a tube that is attached to the gas spring. The body panel is attached to a vehicle frame with a pivotal connection. One of the gas spring and retractable device is connected to the vehicle frame and the other of the gas spring and retractable device is connected to the body panel. The retractable device acts as a solid link as the body panel moves from a closed position towards an open position. Once a center of gravity of the body panel rotates beyond the pivotal connection, the retractable device resists further movement of the body panel until a fully open position is achieved.
Abstract:
A seal that is particularly suitable for use in a gas spring and other high pressure hydraulic and pneumatic sealing applications and that minimizes the leakage of relatively high pressure gas and lubricating oil from the rod end of the gas spring or the other applications. The generally annular seal body includes radially inwardly and outwardly facing surfaces and non-concave axial facing surfaces. Lobes for sealing, wiping and directing enhanced forces project radially beyond the planes of the radially inwardly and outwardly facing surfaces. The seal also includes a wiper insert that has a parabolic shaped radially outwardly facing surface and a radially inwardly facing surface, and that is secured in a recess adjacent to the front corner of the seal body's radially inwardly facing surface. When the seal body is compressed for use, the compression induced stresses in the seal body result in the formation of an effective gas and oil seal because, in part, one of the corners of the insert's radially inwardly facing surface is forced against the adjacent surface of the piston rod.
Abstract:
A self centering, bi-directional, non-cavitating damper that includes a cylindrical damper body and a piston assembly having a piston reciprocally movable in the damper body and a piston rod connected and movable with the piston. A tube is connected with the piston rod and is spaced about and radially from the damper body so that the tube and damper body may move axially, relative to each other, but are normally positioned in centered positions with respect to each other. First and second plastic washers are positioned between the damper body and the tube. At least one coil compression spring is positioned between the damper body and the tube and biases the washers apart axially to their normal positions. Each washer is prevented from moving apart beyond its normal position, but is movable toward the other washer, against the bias of the spring, when relative movement, from their normal positions, occurs between the damper body and the tube.
Abstract:
An adjustable speed gas spring primarily adapted for use as a part of a door closing mechanism. The gas spring includes a piston assembly which is disposed within an elongated fluid chamber and which upon relative rotation of the shaft with respect to the tubular body, permits the user to adjust the shaft extension velocity. The gas spring is fully functional in any shaft orientation.
Abstract:
A transversely mounted, single pneumatic spring, and dual bell crank and idler link assembly providing a compact counterbalance for hinged closures such as automobile trunk lids. In an automobile trunk installation, the assembly is installed with the spring in lateral disposition in the forward upper portion of the trunk, thus being effectively concealed. Alternative pneumatic spring enhancements, e.g., a multi-output force feature and a pressure decay compensation feature may be incorporated in the spring unit to enhance opening of the lid and to improve life expectancy of the pneumatic spring by minimizing and effectively negating pressure loss due to leakage of gas past the shaft seal. Excess spring cylinder length can provide space or volume zones used for the enhancement features. Structure which provides a multiple output force for the pneumatic spring, utilizes positioning of the spring shaft end bushing and seal to vary the working volume by changing effective cross-section area of the piston shaft near the end of a compression stroke. The extra cylinder length enables a sealed partition wall to separate extra volume and the operative volume part of the cylinder. The extra volume is filled with a supply of gas under higher pressure than that of the spring operative gas pressure and, in conjunction with permeability characterisitcs of the spring shaft seal and the partition wall seal, enables compensation for leakage from the cylinder. Multiple force output provisions can be used in a substantially vertically disposed spring, filled with a predetermined quantity of oil, and used as a liquid-pneumatic shock absorber. A supplemental orifice type disc valve unit can be used in such a shock absorber, located near the closed end of the spring cylinder.
Abstract:
A seal that is particularly suitable for use in a gas spring and other high pressure hydraulic and pneumatic sealing applications and that minimizes the leakage of relatively high pressure gas and lubricating oil from the rod end of the gas spring or other application. The generally annular seal body includes a number of convex sealing lobes on its radially inwardly and outwardly facing surfaces. All of the sealing lobes have a predetermined radius and project radially beyond the plane of their respective surfaces. The axial facing surfaces of the seal body are generally flat or non-concave. The seal also includes a wiper insert secured in a recess in one corner of the radially inwardly facing surface of the seal body. When the seal body is compressed between the relatively movable, annularly spaced piston rod and cylinder of a gas spring or application, the compression induced stress in the seal causes the seal body and insert to form an effective gas and oil seal.
Abstract:
A seal that is particularly suitable for use in a gas spring and other high pressure hydraulic and pneumatic sealing applications and that minimizes the leakage of relatively high pressure gas and lubricating oil from the rod end of the gas spring or other applications. The generally annular seal body includes a number of convex sealing lobes on its radially inwardly and outwardly facing surfaces. All of the sealing lobes have a predetermined radius and project radially beyond the plane of their respective surfaces. The axial facing surfaces of the seal body are generally flat or non-concave. The seal also includes a wiper insert secured in a recess in one corner of the radially inwardly facing surface of the seal body. When the seal body is compressed between the relatively movable, annularly spaced piston rod and cylinder, the compression induced stress in the seal causes the seal body and insert to form an effective gas and oil seal.