Abstract: A gas shock absorber has a pressure tube which defines a working chamber. A piston divides the working chamber into an upper working chamber and a lower working chamber. A series of extension passages extend through the piston and are opened and closed by an extension valve assembly. A first and a second series of compression passages extend through the piston and are opened and closed by a first and a second compression valve assembly, respectively. A rod guide assembly is located between the pressure tube and a piston rod. The rod guide assembly includes an oil chamber for sealing and lubricating the piston rod.

Abstract: The present invention relates to a hydropneumatic shock absorber. This new telescopic system comprises an outer sliding tube, an inner sliding tube and structure for adjusting the braking level of the shock absorber in expansion. Fastened on the base of the outer sliding tube is the bottom of a barrel on which rests an elastic structure, such as a counter-acting spring, which pushes on the inner sliding tube in the expansion stroke. The inner sliding tube carries at its internal end a bell which cooperates with a stop spring when in the expansion stroke. The liquid filled barrel contains an axially movable piston connected to the closure plug assembly with the piston contains a first valve, which opens only in the compression phase, and a second valve, which acts as variable throttle and is controlled by the padded end of a screw axially placed within the support tube. By acting on a screw, the expansion braking level of the shock absorber can be adjusted.

Abstract: A piston valve assembly for regulating the flow of fluid through a mono-tube fluid vehicle damper is provided. The assembly includes a piston rod and a piston end having opposing first and second surfaces secured to the piston rod by a connector. A first outer annular seat is spaced radially from the piston rod and extends from the first surface. At least one first fluid passageway connects a first opening between the piston rod and the first outer annular seat and the second surface for providing fluid communication therebetween. A first blow-off valve has a hollow cylindrical portion with a first flange extending transversely from an end thereof with the first flange adjacent to the first outer annular seat when the first blow-off valve is in a closed position. The piston rod and connector secure the blow-off valve to the piston end. The first blow-off valve is movable to an open position away from the first surface.

Abstract: A piston for a piston/cylinder assembly is fastened to a piston rod and axially movably arranged in a working cylinder filled with damping medium. The piston having damping valves for the tension and compression movements of the piston in the cylinder and having a first and second group of passage ducts respectively for the tension and compression directions. The outlet sides of each of the first and second passage ducts open into a control edge covered by valve disks. The first and second passage ducts run axially parallel over at least part of their length, wherein the inlet and outlet regions of each of the first and second passage ducts being arranged axially one behind the other and one of the first and second groups of passage ducts emerges on the end face and the other of the first and second groups of passage ducts emerges radially outward on each side of the working piston.

Abstract: A gas spring includes a cylinder containing a fluid at least part of which is a compressed gas. The cylinder receives a piston that is affixed to a piston rod and divides the cylinder into two working chambers. The piston has a one-way valve that is cycled in response to the direction of motion of the piston and pressure-control valve consisting of a spring and a valve body. In a partial stroke region of the piston a bypass allows fluid flow past the one-way valve and the pressure-control valve. The partial stroke region is adjoined by a bypass-free stroke region, the gas spring being arrested in the bypass-free stroke region. The spring of the pressure-control valve has a temperature-dependent elastic force, the elastic force of the spring increasing with increasing operating temperature, owing to which the compressive force necessary for opening the pressure-control valve increases to an equal extent.

Abstract: Apparatus for preventing the unwanted extension of a hydraulic lock when the lock is subjected to relatively high dynamic loads. The lock includes a hydraulic cylinder having a piston slidably mounted therein. The piston is secured to a piston rod which passes outwardly through one end wall of the cylinder. The lock is placed in tension when the piston rod is being extended and in compression when the rod is being retracted. A flow channel is formed in the piston through which fluid is exchanged from one side of the piston to the other. A manually operated spring biased control valve is mounted in the flow channel which is normally held closed by a set spring. Fluid is allowed to flow when the valve is manually opened or when the lock is placed in tension by some external force that overcomes the biasing force of the set spring. A velocity sensitive restrictor is also mounted in the flow channel that closes the channel when the lock is placed in tension by a dynamic force above a predetermined velocity.

Abstract: A gas shock absorber has a pressure tube which defines a working chamber. A piston divides the working chamber into an upper working chamber and a lower working chamber. A series of extension passages extend through the piston and are always left open. A series of compression passages extend through the piston and are opened and closed by a compression valve assembly. A rod guide assembly is located between the pressure tube and a piston rod. The rod guide assembly includes an oil chamber for sealing and lubricating the piston rod.

Abstract: A pneumatic movement damper has a cylinder closed on one side, a piston that slides within the cylinder and is connected to a piston rod, a packing mounted on the piston and a throttle passage arranged in the piston for connecting the two cylinder spaces separated by the piston and the packing. The piston has a conical seat that widens away from the piston rod and a flange part adjacent to the largest diameter of the conical seat. The packing has a truncated recess that matches the conical seat and can move within limits in the axial direction between the flange part and a ring-shaped flange arranged on the piston rod at an axial distance from the flange part. Radial grooves are provided in the faces of the flange part and ring-shaped flange normal to the axis of the cylinder and oriented towards the packing. The groove provided in the flange part has a smaller cross-section than the groove arranged in the ring-shaped flange and forms the throttle passage.

Abstract: A damper provides tunable variable rates in both extension and compression operation. A piston is carried in a cylinder tube separating out extension and compression chambers. The piston carries a first valving assembly that is tuned to provide a first damping level when fluid flows through the piston from the extension chamber to the compression chamber and a second valving assembly that is tuned to provide a second damping level when fluid flows through the piston from the compression chamber to the extension chamber. A control valve assembly is mounted to move with the piston. When the control valve assembly is closed, fluid flow between the compression and extension chamber flows substantially only through the first and second valving assemblies and when the control valve is open at least some fluid flows between the compression and extension chambers through a secondary valve assembly without passing through the first and second valving assemblies.

Abstract: A shock absorber utilizes a single flexing disc assembly includes a flexing disc which is capable of performing the flexing disc function normally required for allowing the passage of fluid between the two sides of a shock absorber while also providing the blow off function. The flexing disc is backed by a ridge formed on a spring seat. The ridge defines a ring that is concentric with the central long axis of the piston rod. Under normal rebounding conditions, the pressure of rebounding damping fluid builds to the point that the flexing disc is opened somewhat by flexing to allow normal bleedthrough. However, in the event that the rebound pressure builds to a higher, predetermined value, the valve flexes to an extreme degree against the ridge formed on the spring seat. In this manner, the ring acts as a fulcrum, and a quantity of damping fluid is allowed to pass thereby until normal rebound pressure values are reached.

Abstract: A damping cylinder having a staged rate of movement. The cylinder includes a tube, a rod extending from the tube, and a piston carried by the rod within the tube. A liquid at least partially fills the cylinder, and the piston travels within the liquid. A port through the piston permits the liquid to flow through the piston as the piston moves within the cylinder. The piston also carries a normally open flapper valve over the port. If the flow rate of the liquid through the piston is below a preselected maximum rate, the flapper valve remains open. If the flow rate of the liquid exceeds the preselected maximum rate, the flapper valve closes over the port to prohibit flow beyond the maximum rate. In preferred embodiments, a pair of flapper valves is included to limit the rate in both directions, and a bleeder bypass port is included to permit reduced rate movement of the piston after either or both of the flapper valves close.

Abstract: The present invention relates to a hydropneumatic shock absorber. This new telescopic system comprises an outer sliding tube, an inner sliding tube having an adjustable braking level of the shock absorber in expansion. Fastened on the base of the outer sliding tube is the bottom of a barrel on which rests counter-acting spring, or other elastic device, which pushes on the inner sliding tube in the expansion stroke. The inner sliding tube carries at its internal end a bell which cooperates with a stop spring when in the expansion stroke. The liquid filled barrel contains an axially movable piston connected to the closure plug assembly of the inner sliding tube by a support tube. The piston contains a first valve, which opens only in the compression phase, and a second valve, which acts as variable throttle and is controlled by the padded end of a screw axially placed within the support tube.

Abstract: A dampener (628) for a shock absorber of a vehicle, such as a bicycle, is mounted within a telescoping front fork including a stanchion tube (116) and a coaxial slide tube (618). The dampener includes an internally received hydraulic fluid sleeve (640) that defines a hydraulic chamber (648) in which a piston assembly (732) is disposed. Movement of the piston assembly through hydraulic fluid within the hydraulic chamber is selectively adjusted by metering the flow of bypass hydraulic fluid to the back side of the piston assembly by adjusting a responsive valve assembly (670) disposed longitudinally within the stanchion tube. The responsive valve assembly includes a piezoelectric bender (702) that is controlled by circuitry (712) to change its biasing relative to a valve member (694) in response to sensed velocity and/or displacement of the piston assembly.

Abstract: A pressurized gas spring, which exerts an expulsion force on the piston rod entailing a maximum extension velocity of the piston rod, includes braking means effective at a velocity of motion due to external forces above the maximum extension velocity for limiting the velocity of motion to a desired measure.

Abstract: The device comprises a cylinder (1) which is divided in two variable volume chambers (3,4) by a piston (2,2'), which has conduits (5,5') for the passage of a fluid from one chamber to the other, and spring means (15) for pushing the piston in a predetermined direction, tending to cause a pressure increase in one of the chambers; the piston is mounted on a rod formed of two aligned rod elements (7,8), with means (9) for bringing closer and separating their adjacent extremities; it comprises means for providing a controlled fluid leak through the conduits (5,5') of the piston, said means consisting of a groove (25) provided in the piston (2') or washers (12,13) which can be deformed due to the existence of an undercut (33) in one of the rod elements. It provides for the automatic return of the seat and/or the back of the seat to a predetermined position when the passenger leaves the seat.

Abstract: A vibration damper, whose cylinder tube is divided into two work chambers by a piston, is attached to a piston rod. A damping valve includes a damping valve body. Embossed areas have been formed into the main body of the damping valve body. The damping valve embossed areas serve as valve support surfaces with fluid passages, which fluid passages are covered by valve disks on the valve support surfaces. The damping valve body is disk-shaped, whereby the damping valve is equipped with at least one restrictor plate, which restrictor plate partially covers the inlet side of the fluid passages for at least one direction of flow, whereby the restrictor plate has recesses for the embossed areas of the damping valve body.

Abstract: The orientation insensitive, non-cavitating differential, bi-directional damper has a tubular body defining a closed, elongated chamber that has a first end and a second end. A piston assembly is disposed in and is movable within a portion of the chamber. One end of a piston shaft is connected with the piston assembly and the other end of the shaft extends out of one end of the chamber. Another assembly is disposed in the chamber between the piston assembly and the other end of the chamber. A floating piston is disposed in the chamber and is movable in the chamber between the other assembly and the other end of the chamber. The portion of the chamber between the other end of the chamber and the floating piston is filled with gas while the remainder of the chamber is filled with fluid. The floating piston is spring biased toward the other assembly. Orifices in the piston assembly control the rate of fluid flow across the piston assembly when the piston assembly moves relatively to the tubular body.

Abstract: An adjustable damping shock absorber includes a pressure tube with a piston valve assembly slidably disposed within it. The piston valve assembly includes a compression valve assembly which is biased to a closed position and an extension valve assembly which is also biased to a closed position. The damping rate for the shock absorber is adjusted by selectively changing the biasing load of one or both of the valve assemblies. When the biasing load is increased, a firm damping for the shock absorber is produced. When the biasing load is decreased, a soft damping for the shock absorber is produced.

Abstract: A two-stage shock absorber having a pressure tube within which a valve assembly is slidably disposed. A piston rod is attached to the valve assembly and extends out of the pressure tube. In a first embodiment, a ring which is slidably disposed within the pressure tube engages the valve assembly after a specified amount of movement of the valve assembly with respect to the pressure tube In both an extension and compression movement of the shock absorber. The engagement of the ring with the valve assembly reduces the fluid flow through the valve assembly to switch the shock absorber from soft damping to firm damping. In a second embodiment, the ring switches the shock absorber from soft damping to firm damping only during an extension movement.

Abstract: An improved shock absorber for a vehicle suspension system that incorporates an internal damping arrangement that permits a smooth transition between first and second damping rates. The mechanism includes a metering rod that is mounted in such a way that it will self-adjust in its position relative to a bore extending through the piston rod. An arrangement is disclosed for mounting the pistons on the piston rod so as to permit control of their positions without necessitating threaded adjusting devices.

Abstract: A damping mounting structure for use between two members for isolating motion changes which incorporates a plurality of dampers connected between the two members with spring members operating in parallel with the dampers to provide stiffness and where the springs are pneumatic to provide proper stiffness when the load is heavy without damage to the springs and/or to provide variable stiffness when desired.

Abstract: A shock absorber (10) is longitudinally compressible and extendable under the influence of vehicle suspension loads. The shock absorber (10) includes a tubular structure (16) which defines upper and lower hydraulic fluid chambers (52, 50) above and below a piston (18). A control rod (28) is supported for movement longitudinally through the piston (18) simultaneously with compression and extension of the shock absorber (10). The control rod (28) and the piston (18) together define a hydraulic fluid flow path extending through the piston (18) between the upper and lower fluid chambers (52, 50).

Abstract: An air or gas sprung and dampened shock absorber for a bicycle is set forth comprising a cylinder having a closed end and an open end forming a compression chamber, a shaft having a closed end and an open end, the open end of the shaft being reciprocally received within the cylinder through the open end of the cylinder, a piston sealingly positioned in the open end of the shaft and slidably and sealingly positioned adjacent an inner surface of the cylinder forming a rebound chamber in the shaft and a gas spring chamber formed between an outer surface of the shaft and an inner surface of the cylinder wherein the gas spring chamber communicates with the rebound chamber during at least a portion of the compression and rebound stroke of the shock absorber. The shock absorber further includes a compression plate sealingly received in the shaft with an axial position of the compression plate being selectively moveable within the shaft for varying a total volume of the shock absorber.

Abstract: A shock absorber utilizes a single flexing disc assembly includes a flexing disc which is capable of performing the flexing disc function normally required for allowing the passage of fluid between the two sides of a shock absorber while also providing the blow off function. The flexing disc is backed by a ridge formed on a spring seat. The ridge defines a ring that is concentric with the central long axis of the piston rod. Under normal rebounding conditions, the pressure of rebounding damping fluid builds to the point that the flexing disc is opened somewhat by flexing to allow normal bleedthrough. However, in the event that the rebound pressure builds to a higher, predetermined value, the valve flexes to an extreme degree against the ridge formed on the spring seat. In this manner, the ring acts as a fulcrum, and a quantity of damping fluid is allowed to pass thereby until normal rebound pressure values are reached.

Abstract: Vibration damper with adjustable damping force, comprising a pressure tube filled with damping medium, in which a piston on an axially movable piston rod divides a work chamber into a chamber closer to the piston rod and a chamber farther from the piston rod, whereby there is a flow of damping medium between the two work chambers, which flow is divided into a main stream and side stream, a damping valve device consisting of a damping valve body with one main damping valve in each direction of flow, each of which is formed by a main stage valve body and a pilot stage valve which actuates the main stage valves, an adjustable actuator which controls a flow connection between a control chamber and a work chamber, and the main stage valve carries the flow of the main stream and the pilot stage valve carries the flow of the side stream in both directions of flow, characterized by the fact that the side stream in the pilot, stage valve flows through a non-return valve system, that the pilot stage valve has two contr

Abstract: A damper includes a piston that carries a relatively compact control valve for controlling fluid flow through the piston. The control valve provides a variable amount of damping by regulating damper fluid flow between the extension chamber and the compression chamber of the damper during extension and compression strokes. Pressure regulation across the piston is controlled through two alternate flow paths as determined by the control valve. Damping through the first flow path is relatively soft and is determined according to the deflective characteristics of first and second single bi-directional annular disc valves in parallel. Damping through the second flow path is relatively firm and is determined solely by the second bi-directional single annular disc.

Abstract: An adjustable shock absorber having a movable sealing piston located within the shock absorber for sealing fluid and a suspension adjuster connected to the shock absorber for moving fluid between the adjuster and the shock absorber so as to change the overall length of the shock absorber without changing the stroke length.

Abstract: A railway buffer capsule comprising a hollow cylindrical plunger slidably mounted in a cylinder. The cylinder is closed at one end. The plunger is closed at its outer end, and in its inner end is formed a fixed area orifice of flow restricting dimensions. A floating piston slides in the bore of the plunger and separates a liquid reservoir from the remainder of the interior of the plunger which comprises a gas containing space. A stepped piston has its larger diameter exposed to pressure in the reservoir and its smaller diameter end adapted to seat and close the orifice and be exposed to compression chamber pressure. The combination of the stepped piston and the orifice is a multiplier valve which multiplies the resistance of the compressed gas to lengthwise compression of the buffer.

Abstract: An adjustable damper is provided with a variable electrically controlled damping rate being effected through the use of a sliding spool control valve carried on the piston in cooperation with a passive damping valve also carried on the piston to provide a compact and unitized assembly. Damping fluid flow through the piston passes through both the control valve and the passive damping valve.

Abstract: A hydraulic ball coupling assembly (1) comprises an inner hub (2) and an outer hub (3) disposed for relative coaxial rotational engagement. The inner hub (2) includes a continuous sinuate recessed track (4) extending circumferentially around the cylindrical outer surface (5). The outer hub (3) includes a plurality of uniformly spaced axially extending grooves (6) on the inner cylindrical surface (7). The grooves (6) extend in a direction substantially normal to the general effective direction of the sinuate track (4). A slider (10) is reciprocally disposed within each groove (6) and located in the intersecting region (11) of the sinuate track (4) and the respective groove (6) such that relative rotation of the inner and outer hubs (2, 3) causes each slider (10) to oscillate axially within its respective groove (6) while traversing the track (4).

Abstract: A damping valve, in particular for a vibration damper for a motor vehicle, has a damping valve body with at least one admission channel for each direction of flow through the valve body. The admissions channel connectes a top side and a bottom side of the damping valve body to one another. There can also be a valve plate on a valve seat surface, whereby the valve plate can lift up from the valve seat surface, and the admission channels from the top side and bottom side of the damping valve can have an initial choke inside the connection path. The cross section of the initial choke is defined by the width of an influx opening of the admission channel and the average radial distance between an edge, which determines the valve plate contour, and the inflow opening.

Abstract: A hydraulic strut for a motor vehicle for providing a movement guiding and dampening function can generally have a cylinder, with a piston disposed in the cylinder to divide the cylinder into at least first and second chamber portions, with a piston rod extending from the piston out of the cylinder. The cylinder can be sealed at both ends, and can preferably be filled with hydraulic fluid. The piston can preferably define a flow connection between the two fluid chambers, and this flow connection can typically have some sort of valve arrangement therein for controlling flow of fluid between the first and second chamber portions.

Abstract: Shock absorber with adjustable damping force, comprising a pressure tube filled with damping medium, in which a piston on an axially movable piston rod divides a work chamber into a piston-side and a non piston-side chamber, whereby there is a damping medium flow between the two work chambers, which is divided into a main flow and a bypass flow, a damping valve device consisting of a damping valve body, with a main stage valve for each flow direction, each of which is formed by a main stage valve body, and a pilot stage valve which activates the main stage valve, an adjustable actuator, which controls a flow connection between the control chamber and a work chamber, whereby the control chamber is limited axially by the first and second spring-loaded main stage valve bodies, whereby the first main stage valve body, during the inflow from the closed valve position into an open position, is moved axially into the control chamber toward the second main stage valve body, which is held in the closed valve position

Abstract: An adjustable suspension system which has a shock absorber affixed to the suspension system, a movable sealing piston located within a shock absorber for sealing fluid and a suspension adjuster connected to the shock absorber for moving fluid between the adjuster and the shock absorber. A conduit connects the suspension adjuster and the shock absorber. The conduit also includes a hose connecting the suspension adjuster with the shock absorber. A shock housing is adjacent to and outside the shock body. The shock housing surrounds the periphery of the shock body. The shock housing and the shock body define a passageway for fluid. The shock body has a portion that defines at least one port hole between the shock cap and the sealing piston. The shock absorber includes a fluid chamber defined by a shock cap, a shock body, and the sealing piston.

Abstract: An elastomeric shock absorber having enhanced damping characteristics comprises a casing filled with a compressible elastomer; a piston rod immersed in the elastomer; a piston head mounted on the piston rod and the piston head is provided with connecting ports communicating with the front and back spaces of the piston and is also equipped with a mobile member. The mobile member is located between a surface from which the connecting ports emerge as well as a ring or like stop block. The stop block is mounted on a section of the piston head facing a flow chamber, wherein the piston head moves into and out of an outer cylindrical surface of the casing and wherein at least one groove is provided on an inner surface of the casing, which together with the outer cylindrical surface of the piston head form a flow chamber shaped as a solid of revolution, the solid of revolution being selected from the group comprising a cone, a ring, a torus and any combination thereof.

Abstract: A shock absorber has an arrangement for bringing about different kinds of damping characteristics, in response to external controls and independently of how the piston speed varies. The shock absorber comprises a piston which works in a cylinder (2) and which has a passage between upper and lower sides (1a, 1b) of the piston. The changes in the damping characteristics are obtained by a restriction in a channel through which a shock absorber medium or fluid flows. A first valve element (7) exerts an influence on the restriction in response to a first pressure which is created by a pilot flow running between the upper and lower sides at the piston. The pilot flow is determined by a second valve element (8) which is controllable by electrical control signal.

Abstract: This invention relates to a hydraulic damper arranged between a vehicle chassis and a wheel axle for use in attenuating a vibration transmitted from a road surface. A leaf valve and a main valve are provided at an inner seat and an outer seat having different heights to each other arranged at outlet ports of a piston in such a way as they may be opened or closed, the leaf valve is supported at its base end by a stopper provided with a tapered or curved surface at is upper surface. The main valve is arranged in such a way as it may be floated up and down in opposition to the outer seat. A load of the main valve is set only with an inertia of a spring, so that an attenuation force can be stabilized, and the leaf valve is supported by the tapered or curved surface of the stopper when flexed, resulting in that no cracks are generated.

Abstract: A frame having rear suspension system for a two-wheel cycle such as a bicycle or motorbike. The suspension system includes a tubular shock absorber whose outer tubular housing is integrated into a cast or machined lower lug. Several of the main frame tubes and the pedal shaft bearings are also mounted to this lug. By integrating the outer tube of the shock absorber into the tube junction lug, a substantial savings in weight and components is obtained in the chassis assembly while still providing a suspension system.

Abstract: A hydraulic positioner of the type having a piston movable in a hydraulic cylinder and a valve actuatable for releasing the piston for movement in the chamber is provided with a continuously adjustable mechanism for limiting the stroke of the piston. The cylinder and the stroke limiter share a common tubular housing which is partitioned to define the hydraulic chamber, thereby simplifying the device.

Abstract: A hydraulic dashpot for motor vehicles. It has a cylinder that accommodates a fluid. A shock-absorbing piston travels back and forth in the cylinder and divides it into two displacement chambers. The piston is connected to a rod that extends through a centering component at one end of the cylinder. A hydraulic decompression-stroke limiter consists of a cup-shaped recess below the rod-centering component and of another piston on the piston rod above the shock-absorbing piston. Channels extend through the stroke-limiting piston and are blocked off in the decompression-stroke direction. The object is a less expensive dashpot. The stroke-limiting piston consists of a thin stroke-limiting disk with a diameter slightly shorter than the critical diameter of the recess and resting on a thicker support.

Abstract: In an artificial leg for a person having an upper thigh cut and a knee joint lost, a cylinder disposed between upper and lower leg members, which are coupled through a pivotable joint, for controlling bending and straightening of the joint by an air cushion for convenience of walking. The cylinder includes a cylindrical sleeve closed at both ends and a piston having a piston rod and sliding in the sleeve, and has its structure improved by using as a cushion one of two inner cavities separated by the piston, which encloses the piston rod, thereby buffering butting between the upper and lower leg members to remove unpleasant shock resulting at the end of straightening the joint.

Abstract: A valve for controlling a liquid in an hydraulic vehicle shock absorber includes a displacement machine mounted within a passageway in a piston moveable in a cylinder of the shock absorber. The displacement machine includes at least one operative body rotatable by flow of the liquid. A brake is provided for braking the movement of the rotatable body of the displacement machine thereby causes a reduction in the flow velocity of the liquid passing through the valve and a desired damping force. The brake is actuated by an actuating unit.

Abstract: In the disclosed hydraulic shock absorber, damping force characteristics are adjusted in accordance with the frequency of stroke, and the damping force is made small at the time when the directions of stroke are changed from one to the other. Cylinder upper and lower chambers are communicated with each other through main hydraulic fluid passage and first and second bypass passages. During the extension stroke, the second bypass passage is cut off by a check valve, and a shutter in the first bypass passage is slid in accordance with the frequency of stroke by the fluid flowing through an orifice passage to regulate the passage area of the first bypass passage. During the contraction stroke, the first bypass passage is cut off by a check valve, and a shutter in the second passage is slid in accordance with the frequency of stroke by the fluid flowing through an orifice passage to regulate the passage area of the second bypass passage.

Abstract: A pneumatic, rotary, rack and pinion actuator with counter-pressure actuated damping device. The actuator comprises first and second rack and piston assemblies reciprocable inside corresponding pneumatic cylinders, which engage on the opposite sides of a pinion and output shaft. Each rack and piston assembly is provided with an axially extending duct opening at opposite ends into a drive chamber and a counter-pressure control chamber, respectively; counter-pressure control and damping means are provided in the piston-assemblies and cylinders, comprising a throttling valve opening into the control chamber and a check valve in said ducts; a thrust pin member protrudes in the control chamber and into the duct end to open the check valve and feed in a controlled manner pressurised air from the drive chamber into the control chamber, before each rack and piston assembly reaches the end of its stroke.

Abstract: This invention relates to an above knee prosthesis which employs a hydraulic damper to passively regulate the angular velocity or rotation of the artificial knee joint. A programmed microprocessor recognizes common gait patterns from information received from bending moment strain and knee angle sensors on the prosthesis. The microprocessor, under the control of a rule-based program, reacts at various transition points in the gait by activating a motor which in turn adjusts a valve assembly in the damper. The valve assembly is capable of variably and separately damping the knee joint motion in each of flexion and extension at the same time. Gait is improved because of the improved extent of control of knee action. In addition, distinct routines such as stair descending and sitting down can also be practiced.

Abstract: The invention provides a hydraulic shock absorber for controlling an attenuating force in a very low speed range and a medium or high speed range of the speed of a piston. A leaf valve for the high speed range and another leaf valve for the medium or high speed range are disposed for opening and closing movement at an exit end of a port formed in a partition wall member such as the piston. The leaf valve for the low speed range is supported at a rear face of an inner peripheral portion thereof for up and down floating movement on an upper face of a valve stopper. In the medium or high speed range, the leaf valve for the low speed range is deflected to move the inner peripheral portion thereof floatingly, which prevents the leaf valve from being deflected excessively and hence prevents a possible break of the leaf valve.

Abstract: A dual-tube shock absorber having a damping piston, which is joined to a vehicle body via a piston rod; an inner cylinder, guiding the damping piston, that is disposed in an outer cylinder which is connected to the vehicle axle and that together with the damping piston encloses an upper and a lower liquid-filled pressure chamber; a check valve which enables a liquid flow from an compensation chamber enclosed by the outer and inner cylinders to the lower pressure chamber; and a line, joining the upper pressure chamber to the compensation chamber, in which line a device is disposed that effects the damping of the shock absorber and is preferably electrically adjustable. To assure a long service life of the device, which is preferably embodied as a throttle valve, and to facilitate the laying of control cables, the line is extended through the damping piston, and the device is integrated with the damping piston.

Abstract: A hydraulic damper has a dashpot piston reciprocating in a cylinder bore. Piston rods extend axially from both sides of the piston. Sealing structures at both ends of the cylinder connect to the cylinder and sealingly engage the piston rods to form two symmetrical hydraulic working chambers divided by the dashpot piston. A narrow passage through the piston provides a restricted fluid flow path between the two working chambers for hydraulic damping of piston motion. A cavity in the first piston rod is provided with a spring-biased, sliding reservoir piston forming a pressurized hydraulic fluid reservoir connected to the midpoint of the narrow passage between working chambers by a narrow conduit. Both narrow passage and conduit have fixed dimensions and no valves. A cavity in the second piston rod contains a spring centering mechanism.

Abstract: A two-stage shock absorber comprises a casing having a low level damping piston rod therein an end portion of which has two spaced apart flanges thereon with a low resistance fluid path formed therebetween. A floating ring piston is slidingly seated about the piston rod between the flanges and has high resistance throughbores therein. When vibrational forces become excessive to a point where one or the other of the flanges engages against the floating ring piston, the low resistance fluid path is closed off by the floating piston and the high resistance throughbores engage within the fluid flow system to cause a shift from primary low level damping to a high level damping. Once pressure within the system equalizes and the ring piston is no longer in contact with either of the flanges, low level damping resumes.

Abstract: The hydraulic damper according to the invention has at least one restricted communication passage (47) between its two working chambers (8, 9) whose cross section is controlled by a viscous restriction valve (51) positioned via a control pressure of a fluid of a control damper with at least one secondary chamber (41, 42) delimited in a secondary cylinder (39) by a control piston (40), which cylinder and control piston are integrally attached, one to the main body (1), the other to the damping piston (4) of the damper, such that the damping law of the control fluid positioning said valve (51) is linked to the relative displacements of the main body (1) and damping piston (4).Application to the equipping of elastic-return struts with integral damping, in particular for helicopter rotors and blades. FIG. 2.