Abstract: A hydro-pneumatic suspension system includes one or more hydraulic suspension cylinders mounted between the vehicle body and the axle. Each cylinder includes a piston chamber and rod chamber, each of which are connected to an accumulator and which can be connected to a pressure source and a tank by valve systems. The valve system for the rod chamber includes a first solenoid valve and a hydraulically and electrically actuated proportional pressure adjusting valve. The proportional valve is exposed to rod chamber pressure and to tank pressure. The rod chamber pressure can be applied on the proportional valve either directly as control pressure or can be detected with a sensor, and can be used to control the proportional valve. Such a system can influence the dependency of the suspension stiffness on the axle load and can be used to adjust the stiffness to ballast conditions and operating or driving states.

Abstract: A buckling restrained brace includes an elongate, hollow sleeve, an elongate yielding core extending substantially through the length of the sleeve, and a buckling constraining element between the yielding core and the inner surface of the hollow sleeve and spaced apart from at least one surface of the yielding core, leaving a gap therebetween. The buckling constraining element may be spaced apart from and, thus, the gap may exist between two or more surfaces of the yielding core. Additionally, an inner sleeve, or liner, may be positioned between the buckling constraining element and the yielding core, with the liner being spaced apart from at least one surface of the yielding core. The buckling restrained brace is useful in absorbing loads, such as seismically induced loads, that are exerted upon a steel frame.

Abstract: A vehicle suspension system is designed such that its equation of motion can be decoupled. Such a suspension system is provided with actuators, and the actuators are optimally controlled to reduce vibration of the suspension system.

Abstract: A method and system for calculating a control function for a structural system (10) that can be used to determine an appropriate control force to apply to an active member (18) within a stationary member (12) on the structural system (10). An active member (18) and a stationary member (12) are defined as a two-mass system in which the active member (18) and the stationary member (12) move in opposite directions. The stationary member (12) is mounted to an isolation subsystem (14) that is composed of six isolators (28) at multiple degrees of freedom. The isolation subsystem (14) is softer than the stationary member (12), active member (18) and a spacecraft surface (16) due to a damping element (32) of the isolation subsystem (16). The isolation subsystem (16) is mounted to the spacecraft (16) and decouples the spacecraft (16) from the stationary member (12) and thus the active member (18). An accurate control force for the active member (18) can be determined based upon the above structure (10).

Abstract: The present invention is a computer controlled display device. In one embodiment, the display device includes a flat panel display having an input for receiving display data. Additionally, a moveable assembly may be coupled to the display. The moveable assembly may provide at least three degrees of freedom of movement for the flat panel display device. Additionally, the moveable assembly may have a cross-sectional area, which is substantially less than a cross-sectional area of a display structure of the flat panel display.

Abstract: A shock absorber includes a gas compartment within its reservoir compartment. The gas compartment contains gas at a pressure beyond atmospheric pressure. The gas compartment may be defined by an elastomeric bladder which separates the fluid and gas in the shock from one another, and prevents the fluid from becoming aerated during operation of the shock. Because the shock absorber is pressurized beyond atmospheric pressure, the shock absorber provides a “spring assist” to the main suspension spring. The bladder acts as diaphragm and pressure in the bladder is directly transmitted to the fluid. As the main chamber of the shock absorber is replenished with fluid from the reservoir chamber, the gap in the reservoir chamber is taken up by the ever-expanding bladder, and no cavitation occurs in another embodiment, the bladder is replaced by a member mounted for reciprocal sealing movement within the reservoir compartment.

Abstract: An electromagnetic suspension apparatus for an automotive vehicle, employs an electromagnetic actuator interleaved between a sprung mass and an unsprung mass and arranged in parallel with a suspension spring element, and an electric motor built in the electromagnetic actuator for driving the electromagnetic actuator. A motor controller calculates a displacement input, such as a suspension stroke acceleration and a suspension velocity, transmitted to the electromagnetic actuator, and controls the motor to bring a suspension damping force closer to a desired damping force suited for the displacement input. The motor controller calculates an internal inertia force of the electromagnetic actuator, and corrects or compensates for a motor output by the internal inertia force of the electromagnetic actuator.

Abstract: A hydraulic governor device for use with a rotational shaft of a door assembly for controlling a rotation of said rotational shaft.

Abstract: A damper device comprising a first mode having a first level of damping, a second mode having a second level of damping corresponding to a predetermined function, a sensor system having a first output corresponding to a normal position and a second output corresponding to an end stop approaching position, and a control system operable for receiving the first output and the second output and executing the first mode and the second mode. The damper device is operable in the first mode when the control system receives the first output and is operable in the second mode when the control system receives the second output.

Abstract: A hollow elastomer shell with an apex end and a base end with the apex end and the base end having support surfaces thereon to provide compressive support and a pressure equalizer to maintain substantial pressure equalization between the interior of the elastomer shell and the exterior of the elastomer shell to prevent a fluid pressure differential between the interior of the hollow elastomer shell and the exterior of the hollow elastomer shell from prematurely limiting an elastomeric response of the shock isolator.

Abstract: A shock absorber includes a valve assembly with a low speed oil flow circuit and a mid/high speed oil flow circuit. Both circuits control fluid flow through the valve assembly in the same direction. The low speed oil flow circuit is tunable in order to provide low speed damping to improve both the vehicle control and handling. The tuning of the low speed oil flow circuit is accomplished by supporting a low speed valve disc on a chordal edge at a position radially inward of its outer edge to control the rate at which the low speed oil flow circuit opens. The valve assembly of the present invention can be located within either a base valve assembly or a piston valve assembly.

Abstract: A shock isolator for use in a compressive mode comprising a pyramid-shaped elastomer having a cavity therein with the pyramid-shaped elastomer having a base supporting a set of triangular shaped sidewalls that each terminate at a pyramid-shaped apex to create a one-piece elastomer mount so that a force applied to the pyramid apex is transmitted to the base through an offset axis while shock and vibration forces are attenuated by the shear resistance of the shock isolator.

Abstract: The invention comprises a frictional damping strut. The strut comprises an inner cylinder that slides within an outer casing. A spring biases the inner cylinder away from the outer casing in an axial direction. A first wedge member cooperatively engages a second wedge member. The first wedge member having a frictional engagement with the inner cylinder such that when the inner cylinder is pressed into the outer casing the first wedge member bears upon the second wedge member causing the first wedge member to radially expand, thereby increasing a frictional force between the first wedge member and the inner cylinder. A second spring preloads the first wedge member against the second wedge member. A belt tensioner may incorporate the damping strut to preload a belt and damp belt oscillations.

Abstract: An adjustable shock absorber is provided that includes a body having a fluid passageway with first and second passages in fluid communication with one another. A valve assembly is arranged between the passages and includes a plunger that is adjustable between a plurality of positions corresponding to a plurality of fluid flow positions. The valve assembly includes a metering valve having a orifice in a disc, and the plunger includes a needle with a portion disposed in said orifice to provide flow area. The flow area is changed when the plunger moves. The valve assembly also includes a blow-off valve in which the disc is biased to a closed position by a spring arranged between the plunger and the disc. Movement of the plunger changes the loading on the spring. An adjustment knob has a cammed surface that cooperates with the plunger so that as the adjustment knob is rotated the cammed surface moves the plunger.

Abstract: An adjustable vehicle suspension strut configured to be arranged between a wheel assembly and a body of a vehicle, the adjustable strut including a tube. A piston is slidably carried in the tube on a piston rod. A coil is carried on the piston adjacent a first flow passageway in the piston to produce a magnetic field thereacross and a control valve is carried on the piston controlling fluid flow through a second flow passageway in the piston. The control valve is positioned at the distal end of the rod upstream of the first flow passageway.

Abstract: A vibration isolator with non-circular seating features that allow a payload to be attached to a support plate without twisting cables of the isolator. The cables couple the support plate to a piston that can move within an air charged housing. The support plate may have a non-circular shoulder that can sit within a non-circular seat of the housing when the isolator is deflated. The non-circular shapes prevent rotation of the support plate and twisting of the cables when the payload is attached to the deflated isolator. The vibration isolator may also have anti-rotation features to prevent twisting of the cables when the isolator is charged and the support plate is in a fully extended position.

Abstract: A surface effect damper comprising a housing having a wall that defines a chamber, the housing having a first end, a second end and an axis; at least one contact element movable through the chamber between the housing ends in a first direction and in a second direction; and at least two damping elements substantially surrounding each contact element, each of the at least two damping elements being movable away from the axis and into frictional engagement with the wall as the at least one contact element is moved in a first direction and each of the at least two damping elements being movable toward the axis as the at least one contact element is moved in a second direction.

Abstract: A piston rod for use in a magnetorheological dampening device having a surface finish that renders the device resistant to wear at the elastomeric seal/piston rod interface. The piston rod has a surface finish of Ra<0.065 &mgr;m and &Dgr;a≦1.4°, as measured using a Gaussian filter with a 0.08 mm cut-off length. There is further provided a method of achieving the surface finish, including rotating the piston rod while moving an abrasive tape against the outer surface of the rod.

Abstract: The invention concerns a spring barrel module having two chambers. A spring is located in the first chamber and a damper in the second chamber. The unidirectional damper is implemented by a clutch means that connects the damper plate to the spring shaft when the tightened spring is released, whereby the rotation of the damper slows down. Correspondingly, the clutch loosens the connection between the damper plate and the spring shaft when the spring is tightened. In low temperatures (e.g. below 0° C. degrees) the damper fails to dampen the rotation. The unidirectional feature of the damper improves both usability and durability. Breakage of the mechanical components of the spring barrel is prevented by an overload clutch, which means that the spring barrel module will tolerate even relatively rough handling of the equipment.

Abstract: A damper assembly is provided including a telescopic damper having a piston rod extending from a first end. A mount assembly is mounted on the piston rod. A dust tube is provided the damper assembly including a substantially closed end, the closed end positioned between the telescopic damper and the mount assembly. The closed end of the dust tube includes an opening for receiving the piston rod and a rate surface for contacting a bumper portion of the mount assembly when the damper assembly contracts.

Abstract: An arrangement forms part of a shock absorber (1) and is intended to produce distinct longitudinal displacements of an element (7) in response to longitudinal displacements of a screw (15). The displacement directions of the screw and the element diverge and the displacement of the element is designed to occur against the action of a force (14) on the element. The screw is designed with a tapered or inclined surface (17) and the element, or a part related thereto, is pressed against the surface by the said force (14) Interacting sections of the surface and the element, or the part, are designed with structures that produce the said distinct longitudinal displacement positions of the element when acted upon by the member. In this way the element actuation function and that of producing the distinct positions can be incorporated into a relatively simple and compact construction.

Abstract: A suspension system for a motorcycle, comprising a motorcycle main frame, a swing arm pivotally mounted to the motorcycle main frame about a pivot axis, and an air-bag suspension system. The air-bag suspension system includes at least one air-bag constructed of an elastomeric material. The air-bag is housed within a housing assembly and is secured at one end to a piston located within the housing assembly and at its other end to an upper plate or end cap of the housing assembly. The housing assembly is attached to a shock absorber, and the shock absorber is attached at its forward end to the cross member plate of the motorcycle main frame and is pivotally attached at its rearward end to the lower transverse cross member of the swing arm.

Abstract: The braking mechanism comprises a toggle lever, a brake pad, and an incline. An incline actuates the braking mechanism by forcing an extension of the toggle lever. As the toggle lever extends, it pushes the brake pad closer to the surface to be slowed. Multiple toggle levers may be used to distribute the force across the brake pad. This configuration allows a single input from the incline to actuate both toggle levers. By adjusting the width of the incline actuating the toggle lever, the force on the brake pad may be adjusted.

Abstract: A shock absorber is comprised of a cylinder defining a chamber therein, the cylinder containing a fluid; a piston rod sealingly projecting into the cylinder and being axially displaceable with respect to the cylinder; a piston being attached to the piston rod, the piston being slidably disposed within the cylinder to sealingly divide the cylinder into first and second chambers; means for permitting fluid communication between the first and second chambers; the means for permitting fluid communication being disposed in at least a portion of the piston. The fluid is comprised of a polyol ester the polyol component of which is a hindered polyol and the carboxylic acid component is a mono-carboxylic acid having from about 5 to about 18 carbon atoms.

Abstract: A damper includes a barrel axially slidably mounted on a shaft, an elastic ring mounted inside the barrel around the shaft, arched pressure blocks mounted abutted against one another inside the elastic ring around the shaft, each arched pressure block having an axially extended sloping groove, steel balls respectively arranged in the sloping groove of each arched pressure block in contact with the periphery of the shaft, a rigid locating ring mounted inside the barrel to support the steel balls in the sloping groove of each arched pressure block, a screw cap threaded into one side of the barrel, a compression spring stopped between the screw cap and the locating ring, a hollow adjustment screw member threaded into one side of the barrel to support the steel balls in the sloping groove of each arched pressure block against the locating ring.

Abstract: A vehicle suspension apparatus according to the invention includes a vehicle suspension strut and a continuous position sensor coupled to the vehicle suspension strut and adapted to provide information indicative of a continuous position of a first portion of the vehicle suspension strut relative to a second portion of the vehicle suspension strut. The continuous position sensor includes a magnet coupled to the first portion of the vehicle suspension strut and a sensing mechanism coupled to the second portion of the vehicle suspension strut and responsive to the magnet to provide an output indicative of the continuous position of the first portion relative to the second portion.

Abstract: The compensator consists of at least one flexible and preferably elastic braiding (8), fitted up outside onto the cylinder (1) of the shock absorber, seal-fastened with its own ends onto said cylinder by means of suitable fastening means (19, 10) and carried out in such a way as to contain a chamber with variable volume (C) occupied by oil and communicating with at least one of the inside chambers of the shock absorber, for instance with the chamber with the larger volume, by means of holes provided on said cylinder.

Abstract: A device and method for transferring steering responsibility from a first electro-mechanical actuator to a second electro-mechanical actuator comprises a cylinder and a first piston slideably disposed within the cylinder. A second piston is slideably disposed within an interior chamber of the first piston. A first locking sleeve is disposed within the interior chamber, a second locking sleeve is disposed within the interior chamber in opposition to the first locking sleeve, a first spring is disposed within the interior chamber interposed between the first locking sleeve and the first piston, and a second spring is disposed within the interior chamber interposed between the second locking sleeve and the first piston. The pistons and the locking sleeves also each include at least one groove disposed therein. Snap rings may be disposed within the grooves. A damping mechanism may also be incorporated into the structure of the device.

Abstract: The housing of a shock absorber is constructed to include an inner chamber surrounded by an outer chamber. The inner chamber is divided by the piston to which the piston rod is connected into two portions. One of these portion has a number of orifices that fluidly connect that portion to the outer chamber. A piston slidably and movably fitted along the length of the outer chamber divides the outer chamber into two compartments, one of which is in fluid communication with the portion of the inner chamber to which it is connected by means of the orifices. An incompressible fluid is provided in the fluidly interconnected compartment and portion. A biasing force acts against the piston in the outer chamber by means of a pressurized gas provided in the other compartment of the outer chamber. With the shock absorber thus constructed, when the piston rod moves, the piston to which it is connected would force an exchange of fluid between the inner chamber and the outer chamber, which acts as a reservoir.

Abstract: The invention relates to a generator of dynamic loads comprising a main mass/spring system composed of a main mass comprising at least one main mass element of mass M2 and of at least one main spring element of stiffness K2. The device is one which comprises an additional mass/spring system, which is coupled to the main mass/spring system and which is composed of an additional mass of mass m3 and of at least one additional spring element of stiffness K3, the assembly exhibiting a first and a second resonant frequency f0 and f2 respectively, and an anti-resonant frequency f1, with f0<f1<f2.

Abstract: A controllable pneumatic apparatus including a pneumatic actuator coupled with a linear-acting brake including a field responsive medium. The pneumatic actuator has a housing with a gas cavity, a first piston slidably disposed in the gas cavity subdividing the gas cavity into first and second gas chambers, and an output member coupled to the first piston. The linear-acting controllable brake includes a medium containing cavity subdivided into a first and second chambers, and a second piston rigidly interconnected with, and longitudinally aligned with, the first piston. A passageway interconnects the first and the second chambers and a field responsive medium (e.g., a magnetic fluid) is contained in the passageway. A field generator produces a field to change a rheology of the medium and cause a braking force to be applied to the output member to control motion thereof. A preferable control method implements motion control based upon the kinetic energy and the braking force in the system.

Abstract: The present invention is directed to shock absorbers, including position-sensitive shock absorbers (2) in which the position-sensitive damping can be different during compression and rebound strokes, and shock absorbers (60) with damping adjusters (80, 118) which vary the damping provided during compression and rebound strokes. The position-sensitive shock absorber includes a cylinder (4) within which a piston (122) is movably mounted for movement between the first and second ends of the cylinder. Bypass openings (24-32) open into the cylinder interior (6) at axially spaced-apart positions. The bypass openings are coupled by a bypass channel (38). A flow valve (40, 42) may be positioned along the bypass channel permitting fluid flow from the first opening to the second opening and restricting fluid flow from the second opening to the first opening.

Abstract: A device for transferring steering responsibility from a first electro-mechanical actuator to a second electro-mechanical actuator comprises a cylinder and a first piston slideably disposed within the cylinder. A second piston is slideably disposed within an interior chamber of the first piston. A first locking sleeve is disposed within the interior chamber, a second locking sleeve is disposed within the interior chamber in opposition to the first locking sleeve, a first spring is disposed within the interior chamber interposed between the first locking sleeve and the first piston, and a second spring is disposed within the interior chamber interposed between the second locking sleeve and the first piston. The pistons and the locking sleeves also each include at least one groove disposed therein. Snap rings may be disposed within the grooves. A damping mechanism may also be incorporated into the structure of the device.

Abstract: The invention is based on a vehicle transmission with a hydrodynamic retarder (1), the stator (3) of which is supported on a transmission housing (2) and the rotor of which is coupled with the vehicle input drive part of the transmission. The proposal is, that the stator (1) be pivotally anchored in the transmission housing (2) to rotate about the axis of rotation (17) of the rotor within a limited angular area. Further that said stator (1) is supported on at least one spring element (5, 6) on the transmission housing (2), whereby at least one spring element (6) acts upon a regulating piston (8) of the pressure regulation valve (7).

Abstract: The invention relates to an air-controlled damper which attenuates the motion of movable components. Sealing between the movable components is effected by a separation means which is fixed to the cylinder and the piston in the hollow space of the cylinder.

Abstract: A damped mechanical joint assembly comprises two damping members, a joint body positioned therebetween and rotatable relative thereto; and a retainer for maintaining engagement of the damping members with opposite damping surfaces of the joint body. The joint body is provided with a plurality of damping cylinders positioned around the joint rotation axis in a uniformly angularly spaced circular pattern, and each damping cylinder comprises a pair of piston chambers, each opening onto opposite damping surfaces, and a constricted passage connecting the piston chambers. Each of the piston chambers is provided with a piston assembly slidably positioned therein, and each damping cylinder is filled with fluid between the piston assemblies. Each damping member is provided with a circular groove comprising a plurality of uniformly angularly spaced ramped depressions separated by groove barriers. The number of damping cylinders preferably differs from the number of depressions by at least two.

Abstract: An energy absorbing device adapted to be connected between a motor vehicle bumper and a motor vehicle frame includes a liquid filled cylinder having a piston therein connected to the impact receiving device. The cylinder is provided with a plurality of weakened areas along the length of the cylinder which will rupture in sequence upon application of force by the piston to the liquid, thereby dissipating the force applied to the impact receiving means. A spring or an explosive device may be provided between the piston and closed end of the cylinder or the interior walls of the cylinder may be roughened to provide additional resistance to the movement of the piston within the cylinder. Additionally, the liquid expelled from the cylinder can be channeled through various devices to apply a reverse force to the impact receiving device.

Abstract: The present invention relates to a high pressure servo-mechanism to be installed in a civil or architectural structure to alleviate dynamic reaction of the protected structure and to prevent the possible damages to the structure by earthquakes or typhoons thus assuring the security of human lives and properties inside the structure.

Abstract: The invention relates to a damper valve for use on a coupler for hydraulic lines, in particular those which connect a hydraulically actuated servomotor of a servo control to a servo valve. According to the invention, all the elements having a damping effect are arranged captively in the coupler.

Abstract: A vibration proofing structure having a first base and a first oil damper mounted thereon having a first tank mounted on the first base, first pistons arranged in the first tank, and a first rod having a first end mounted on the first pistons and a second end outwardly extending from the first tank. The structure further includes a second oil damper including a second tank, second pistons arranged in the second tank and a second rod having a first end mounted on the second pistons and a second end outwardly extending from said second tank. A second base is provided on which the second end of the second rod is mounted. The first and second oil dampers are juxtaposed to each other and the first rod is connected to the second tank so as to permit the first and second oil dampers to rotate relative to each other.

Abstract: Vibrations of pipes or other components installed in a container such as a tank intended for holding liquids, are damped by surface area damping bodies, e.g. plates with through-holes that are immersed in the liquid in the container. These plates are rigidly connected to the pipes or components to be damped. The vibration damping plates are constructed of metal, for example, and the through-holes reduce the mass and advantageously affect the damping effect. The materials for making the perforated damping plates are selected to be compatible with the content of the containers, such as a fuel in a tank in a spacecraft. The surface area ratio of all cross-sectional areas of the through-holes to the total plate surface area is optimized to achieve a maximum damping effect. These perforated plates are secured to pipes, braces, filters, ducts, or other internal components of fuel tanks of land vehicles, aircraft, and spacecraft.

Abstract: A damping unit comprising: a mass body supported at a position close to a shaft end of an operating shaft in such a manner as to be movable in a direction orthogonal to an axis of the operating shaft, the operating shaft of a working head; wirelike resilient members, an end of each resilient member supporting the mass body, the other end thereof being fixed in parallel with the axis of the operating shaft; fluid chambers disposed so as to enclose the resilient members; and a high-viscosity fluid being charged into the fluid chambers.

Abstract: In a horizontally and vertically acting vibration damper, there is arranged within the damper housing filled with damping medium a series of annular discs, at least one of which is assigned to the damper strut and which are horizontally and vertically movable relative to one another as a whole, the two movements being designated as telescopic. Some of the discs have at their outer edge a driver, so that the horizontal or radial movement of the annular discs can be transmitted to adjacent annular discs after a predetermined travel has been exceeded. By an appropriate calculation of the diameter of the discs, these can be arranged nested one in the other, so that, even with large movements, small constructional sizes are guaranteed.

Abstract: An aircraft landing gear damping mechanism improvement of a damper containing piston means in a chamber of a housing, an orifice in the piston means and Belleville springs disposed in the chamber between the wall of the chamber and the piston means on opposite sides thereof. The improvement comprises means, e.g. in the form of a member having slots therein, and disposed between one end of the Belleville springs and the adjacent chamber wall, providing fluid communication of the inner cavity and outer cavity of the chamber below and above the Belleville springs.

Abstract: A dampener for devices such as a leveling valve in which the dampener is a separate self-contained member formed of a piston cylinder part and a cap connected to each other and having a piston mounted in the chamber between the parts. The cylinder chamber occupied by the piston contains a viscous fluid that passes over the edge of the periphery of the inner wall of the chamber as the piston is moved from one end to the other. The two parts of the dampener are preferably constructed of transparent material so that it can be determined whether the space between the piston and the walls of the chamber is completely filled with a viscous fluid or whether there are any air bubbles or the like in the chamber. A temporary opening is provided in the cylinder cap for escape of air when the two parts are connected together. Extending from both sides of the piston are hubs exposed to the exterior of the dampener.

Abstract: An abutment with a damping device, more particularly for automatic machining or conveying equipment, comprising an abutment member which is able to be moved from a first abutment position as far as second end abutment position while subjected to a damping action. A fluid power operated setting member can move the damping device (which is connected with the abutment member) perpendicularly to the direction of the abutment action and is able then to move the abutment out of an abutment plane and back into it. The damping device has in this case at least one damping piston adapted to run in at least one damping cylinder, there being a choke device which damps the piston movement and provides resistance for the ingoing or outgoing air during piston movement. Both the setting member and also the damping device operate by a fluid power effect, individual adaptation of the damping properties being possible for workpieces with different masses and/or different speeds of movement.

Abstract: A fail-safe variable damping suspension system for a motor vehicle controls the oscillatory spring movements of each wheel via a permanent magnet rotary electric machine which is connected to machine control circuitry by normally open contacts of a relay. In the event of failure of the suspension system, the relay is released and the machine takes the form of a permanent magnet alternator which is connected to a defined load via normally closed contacts of the relay. Thus, in the event of a failure of the suspension system, the machine control circuitry is disabled and all shock absorbers are set to a fail-safe mode by the defined load upon closure of the normally closed contacts of the relay.

Abstract: A rate controllable damping mechanism is disclosed. The mechanism includes a chamber disposed within a housing; an element mounted for movement within the chamber; a damping material, preferably a low melting temperature metal alloy, in the chamber for preventing the movement of the element at a first temperature and for damping the movement of the element at a second temperature; and a heater for selectively increasing the temperature of the damping material from the first temperature to the second temperature. Controlled damping is effectuated by heating the fluid material until it reaches a molten state at which the resultant fluid damps the movement of the element in a conventional manner. A novel method is also disclosed for structural stress relief.

Abstract: The oil supply system for a fluid squeeze film damper carries a high frequency check valve mounted in serial flow relation to a low frequency check valve, wherein the low frequency check valve is disposed between the source of oil and the high frequency check valve so as to maintain the stiffness of the oil film and high level of the average oil pressure.

Abstract: A vibration damper is provided for a towed body usable more particularly as head section of an underwater antenna towed by a boat and containing detection and measuring instruments.The damper of the invention comprises at least one piece with high loss angle in contact with a traction element so that vibrations perceived by the traction element cause deformations of said piece.