Abstract: A system and method for the reduction of noise radiated by a vibrating structure at a given frequency are disclosed. In systems of the invention, a radiation-cancelling device that acts like a resiliently supported mass with a significant sound radiating area is attached to the exterior surface of the structure to be quieted. Radiation from such a device, when constructed so that the motion of the vibrating structure provides the driving frequency for oscillation of the spring-mass system in the radiation-cancelling device and so that the natural frequency of the spring-mass system in the radiation-cancelling device is lower than the vibration frequency of the vibrating structure cancels the sound radiating from the (preferably) considerably larger vibrating surface to which it is attached. If appropriate, more than one radiation-cancelling device may be attached to a given vibrating structure in a system according to the invention.

Abstract: A noise damping device of a rotation driving apparatus includes a housing; and at least one rotating disk installed to be rotated by a driving source within the housing. The rotating disk and the housing are assembled to satisfy the following Equation &dgr;m<h<&dgr;m+1.5&dgr;f &dgr;m is the thickness of air layers which move from the rotation center of the rotating disk to the outside thereof and are distributed around the rotating disk when the rotating disk rotates at a normal operating speed. &dgr;f is the thickness of air layers which move from the outside of the rotating disk to the rotation center thereof and are distributed around the upper inside surface and the base surface of the housing, which face the rotating disk. h is the distance between the rotating disk and the upper inside surface or the base surface of the housing.

Abstract: The drive assembly is formed by an internal-combustion engine which is installed in a passenger car. By means of bearings, supports or the like, the internal-combustion engine is held in position in an assembly space. By means of a wall of a vehicle body, the assembly space is separated from a vehicle occupant compartment. For achieving favorable psycho-acoustic effects, a sound support is provided between the internal-combustion engine and the wall of the vehicle body, by which sound support the engine-mechanical structure-borne sound is transmitted into the vehicle body, specifically for a targeted perception by occupants in the vehicle occupant compartment.

Abstract: A sound generating or emitting machine having a component comprising a material with a high internal damping and tensile strength, the material comprising (1) a metallic base material, and (2) a metallic second phase with an at least partially martensitic structure. The material may also be an alloy comprising a base material in which additional alloy elements have a very low solubility.

Abstract: A noise reducer for construction machinery, which efficiently reduces noise at low cost with durability, is provided. For this purpose, lamination plates (8) which are the plates being laminated are bonded, discretely at a predetermined interval (a1), to a part of or the entire of a noise generating element. Lamination plates (8A, 8E) may be bonded discretely at a plurality of kinds of bonding intervals (a1, a2). The lamination plates (8) with the different number of laminations may be bonded according to a noise generating element.

Abstract: The present invention concerns a watertight apparatus capable of being immersed in a liquid, for example a watertight watch, including a case (1) with an inner chamber (10) communicating with the exterior, the chamber being separated from the exterior by a membrane (17) which can be deformed, defining, on one side, a non-watertight outer zone and, on the other side, a watertight inner zone, in which is housed, in association with the membrane, an acoustic transducer (22), the membrane being fixed by its peripheral edge (17A) in the chamber (10) and applied via elastic memeber (20) towards its periphery, but at a distance from the edge, against a support surface (12) arranged in the inner chamber (10).

Abstract: An arrangement for acoustically uncoupled mounting of slightly vibrating components on an anchoring part has a first sleeve which is adapted to guide through an opening of a component, a mounting screw which extends through the first sleeve, an uncoupling element adapted to be arranged between the component and the anchoring part, a second sleeve mounted coaxially to the first sleeve, a ring-shaped disc provided on each end of each of the sleeves, so that one of the discs is locatable between the anchoring part and the component at the other of the disc is locatable between the component and a head of the screw, the uncoupling element being adapted to be arranged between the component and a disc facing the anchoring part.

Abstract: A noise dampening shroud is configured to surround the generator of lithotriptor device to reduce the noise emissions caused as a result of the generation of acoustic shock waves during extracorporeal treatment of a patient. The shroud comprises an insulating body and a cover. The insulating body comprises sound dampening insulation and is configured to surround substantially all of the housing that typically encases the generator of convention lithotriptors. The cover is comprised of a thin pliant material configured to surround the insulating body and is provided with fasteners for removably securing the insulating body to the generator. When attached to the generator of a lithotriptor device, the shroud greatly reduces the noise emitting by the generation of acoustic shock waves and thereby minimizes the distraction and disturbance caused by such noise.

Abstract: A foot device for supporting electronic equipment thereon comprises a sleeve having an axial through bole, and a plurality of balls one by one in line provided in the hole wherein the bottom and top balls are extended above the axial through hole. As such, in use, the electronic equipment is supported by the extended ball of the foot device, while not in contact with supporting plane. This point based contact has the effect of suspending the electronic equipment in the air, thus eliminating interference. Further, the vibration generated by the electronic equipment is not absorbed and interfered by the supporting plane, resulting in a uniform transmission of vibration to all directions without damping or interfering for achieving a maximum quality.

Abstract: A vibration damped structure, which is excellent in vibration absorption and sound absorption effect, is provided by coating the surface of a structure to be damped with a mixture of molten photopolymerizable resin and a photopolymerization initiator and then subjecting the coated surface to irradiation, whereby a vibration damping coating is formed on said surface.

Abstract: The present invention relates to vibration damped laminate articles having improved force (torque and/or pressure and/or stress) retention and decreased or eliminated spring back. An area defining a through hole and/or the periphery of the article is welded. Methods of making the articles and fastening assemblies including the articles are provided.

Abstract: An in-wall speaker has a variably tuned vibration absorber to absorb and dissipate vibrations in the speaker and surroundings that tend to cause distortions. The vibration absorbing device, including a stack of viscoelastic damping plates, is secured to the speaker or connected structure via a trapezoidally shaped tuning plate, which provides a varying degree of cantilever in different portions of the stack of plates. The effect is to absorb vibrations over a broad range of frequencies.

Abstract: A process for production of a tube profile element having a swaged closed head end includes the steps of chamfering an unswaged end of a tube profile element having a first diameter to provide a chamfered end on the tube profile element having a chamfer angle of less than 45° relative to a longitudinal axis of the end portion of the tube profile element, supporting the tube profile element in a retaining tool such that an end portion of the tube profile element having the unswaged chamfered end thereon extends beyond the retaining tool, providing a swage tool having a negative die capable of swaging the end portion of the tube into a swaged closed head end having a maximum second diameter larger the first diameter of the unswaged end of the tube, and moving the swage tool toward the end portion of the tube and swaging the unswaged chamfered end of the tube, by the negative die of the swage tool, into the swaged closed head end of the tube profile element.

Abstract: A tuned vibration absorber and vibration-reduced pipeline system utilizing same. The tuned vibration absorber includes a support frame, a tuning mass mounted for pivotal movement relative to the support frame about a pivot; the tuning mass including a lever, and a spring contacting the lever. In the vibration-reduced pipeline system, the absorber's support frame is preferably secured atop of the pipeline section, preferably by at least one strap, to absorb vibrations thereof. In a preferred aspect, the tuning mass includes an arm extending from the pivot in a first direction and a weight repositionably mounted thereon. The lever extends from the arm along a second direction substantially orthogonal to the first direction. Preferably the line of action (along A--A) of the spring extends substantially parallel to the first direction. An adjuster is provided for readjusting a position of the tuning mass relative to said support frame due to drift in the spring.

Abstract: A hydraulic pump-motor having an end shield which deadens the sound generated by the pump-motor do thereby result in a quieter unit. The present invention provides a conventional hydraulic pump-motor having an electric motor coupled to a pumping mechanism wherein the motor includes an improved sound attenuating end shield design. Through the use of acoustically deadening materials such as cast iron and polypropylene plastic, the end plates of the present invention deaden the sounds stemming from the vibration of the pump-motor. In addition, the present invention provides an end shield design which allows the stator to be secured to the motor housing and the air gap between the rotor and the stator to be precisely measured prior to the installation of the end shield. The present invention therefore results in not only a quieter pump-motor but also a pump-motor with higher machining tolerances, improved efficiency, and lower production and maintenance costs.

Abstract: An acoustic panel having at least two compressible, flexible, acoustic foam damping layers separated by at least two rigid layers. In one preferred embodiment, a first rigid layer has a second flexible foam layer spray applied, with a further spray application of a rigid third layer, followed by a spray application of a flexible foam fourth layer, followed by a spray application of a rigid fifth layer, followed by a spray application of a sixth flexible foam layer, finally followed by a spray application of a rigid seventh layer. Sound transmission through this embodiment is especially well attenuated at high audio frequencies.

Abstract: An automobile interior component having sound-dampening characteristics has a contact area thereon which contacts a second interior plastic component during operation of the automobile resulting in noise. The interior plastic component has a thermoplastic elastomer self-adhered to the contact area to thereby dampen the noise created at the contact area. A method for making a sound-dampened interior plastic component includes extruding a body of thermoplastic elastomer through a die onto a contact area of an interior plastic automobile component and allowing the extruded body of thermoplastic elastomer to cool, solidify, and adhere to the interior plastic component.

Abstract: A method for reducing the amplitude of vibration and the pressure wave (6) from a radiating surface (5) and/or an incident surface (3) of a material exposed to mechanical and/or acoustic vibration. The material consists of an anisotropically shaped heavy resilient structure with an internal geometry capable of deflecting and localizing vibration (7) within the structure. A specific material may be incorporated into the areas where vibrational energy is localized in order to convert the vibrational energy into another form of energy.

Abstract: A plurality of Helmholtz resonators with varying physical characteristics are mechanically coupled within a structure to drastically reduced acoustic transmission through the structure or along a pipe. These mechanically coupled resonator structures produce much flatter broadband acoustic attenuation than uncoupled resonators.

Abstract: A plurality of acoustical absorption elements are mounted in a two-dimensional spaced array on an acoustically reflective surface of an machinery enclosure, in such a manner as to expose portions of the reflective surface between neighboring elements. The elements are preferably of a substantially standard size and shape in order to enhance production and inventory efficiency, although materials of various thickness may be provided to accommodate tuning for specific frequencies to be absorbed.

Abstract: A flexible plate is formed with a first rigidity about a first axis and a second rigidity about a second axis where the first and second axis are each perpendicular to a central axia about which the flexible plate is rotatable. The first rigidity is greater than the second rigidity such that the flexible plate may flex more easily about the second axis than the first axis, thus providing the flexible plate with an anisotropic flexural rigidity. In one embodiment, the flexible plate is formed with an eliptical intermediate portion. In another embodiment, the flexible plate includes first and second plates. Each plate has a central portion. The first plate has first foot portions and the second plate has second foot portions. The first and second foot portions have differing circumferential widths.

Abstract: A hybrid mode-scattering/sound-absorbing segmented liner system and method in which an initial sound field within a duct is steered or scattered into higher-order modes in a first mode-scattering segment such that it is more readily and effectively absorbed in a second sound-absorbing segment. The mode-scattering segment is preferably a series of active control components positioned along the annulus of the duct, each of which includes a controller and a resonator into which a piezoelectric transducer generates the steering noise. The sound-absorbing segment is positioned acoustically downstream of the mode-scattering segment, and preferably comprises a honeycomb-backed passive acoustic liner. The invention is particularly adapted for use in turbofan engines, both in the inlet and exhaust.

Abstract: A shock absorbing foot device adapted for supporting an audio equipment on a flat surface, including a base adhered to a flat surface, a receptacle fastened to the base by a screw joint and having a top open chamber, a steel ball mounted in the top open chamber of the base, a mounting plate adhered to a bottom side of an audio equipment and having a recessed bottom hole, and a support rod having a rounded top end inserted into the recessed bottom center hole of the mounting plate and secured in place by a shock absorbing ring, a flat bottom end inserted into the top open chamber of the receptacle and supported on the steel ball and secured in place by shock absorbing rings.

Abstract: A platform is interposed between an electronic component of a sound reproduction system and a support structure to absorb unwanted vibrational energy originating in the electronic component and thereby enhance the sonic performance of the electronic component, the platform having a body constructed of a plurality of layers integrated into the body and having densities progressing from higher densities at outer layers to lower densities at inner layers, with an inner layer recessed relative to the outer layers for facilitating the absorption of unwanted vibrational energy.

Abstract: A truss type extruded aluminum section is formed of a pair of planar plates and ribs, wherein hollow portions are formed within said section by the ribs and the planar plates. Vibration-damping resin is provided on the inner surfaces of hollow portions, and particularly on the inner surface of the planar plate and on a single surface of the inclined rib. With this arrangement, the vibration energy bending the planar plate and the rib is converted into a heat energy. In the case of manufacturing such truss type extruded aluminum vibration-damping section, for making easy the insertion of the vibration-damping resin in the hollow portion, the vibration-damping resin is stuck on a plastic film to form a long planar body. The plastic film serves as a cover or an adhesive. Moreover, in the case of directly inserting the vibration-damping resin sheet, the vibration-damping resin sheet is subjected to embossing on the adhesive-bonding side for allowing air to escape.

Abstract: An adjustable, isolation mounting system for center channel loudspeakers has a pair of front mounting feet and a single rear mounting foot extending from a bottom surface of a loudspeaker enclosure. The rear mounting foot is adjustable in height to provide mounting flexibility and stability, and also to adjust the listening axis from the loudspeaker to the listener for optimum sound quality. The rear mounting foot also has a swivel foot member mounted on its bottom end to provide a stable support on irregular mounting surfaces. The front mounting feet are made of a vibration isolating material to isolate vibrations of the loudspeaker enclosure from the mounting surface on which the loudspeaker is supported. A vibration isolating pad is bonded to a recessed bottom surface of the swivel foot member on the rear mounting foot to further isolate vibrations of the loudspeaker enclosure from the mounting surface.

Abstract: A composite shelf in a shelf frame supports a plurality of disk drives and attenuates vibrations in the shelf. In the composite shelf, there is a double wall having an outer wall and an inner wall for supporting the disk drives mounted on the shelf. A stiffener between the inner wall and outer wall strengthens the composite shelf to reduce flexure in the composite shelf when the shelf is loaded by disk drives mounted on the shelf. A damping layer is placed between the stiffener and one of the inner wall or outer wall. This damping layer attenuates vibrations in the composite shelf so as to reduce vibrations transmitted from the composite shelf to the disk drives supported by the composite shelf. A second damping layer is placed between the stiffener and the other wall. Both damping layers attenuate vibrations in the composite shelf so as to reduce vibrations transmitted from the composite shelf to the disk drives supported by the composite shelf. A third damping layer may be placed within the stiffener.

Abstract: An apparatus for counteracting vibrations includes a housing for attachment to a vibrating member. First and second bodies are connected to the housing by first and second springs, respectively, with a combined stiffness which defines a resonant frequency at which the first and second bodies oscillate with respect to the housing. Each of the first and second springs include a plurality of rods fixedly connected between a pair of rings. A lever engages the first and second bodies to vary a spacing between those bodies when force from an actuator is applied to the lever. The lever action alters the stiffness of the first and second springs which varies the resonant frequency of the vibration absorber.

Abstract: A coupling device is interposed between a component of a sound reproduction system and a supporting structure for the draining, transmission and dissipation of vibratory energy generated within the component while isolating the component from vibratory energy emanating from the support structure.

Abstract: An advanced sound reducing tape includes a surface treatment which results is reduced noise when the surface treatment comes into contact with various materials. The surface treatment comprises an arrangement of ridges and depressions disposed across a surface of the tape. The tape is vinyl based and therefore low in cost while providing a similar noise reduction as convention cloth tapes. The tape is typically utilized on a harness within an automobile and reduces squeaks when the harness including the tape comes into contact with interior portions of the vehicle which are typically polypropylene, ABS plastic or steel.

Abstract: A vacuum brake booster having sound absorbing members affixed to the front and rear shells to attenuate sounds caused by air movement in the brake booster. The front shell is joined to the rear shell to define the housing for the brake booster. The housing is divided into a first chamber and a second chamber by a wall structure. The first and second chambers in a first mode of operation are designed to be in communication with a first source of fluid (vacuum) having a first fluid pressure while in a second mode of operation the second chamber is in communication with a second source of fluid (atmospheric air) at a second fluid pressure. In the second mode of operation, a pressure differential is created across the wall structure to produce an output force corresponding to an input force associated with a desired braking application.

Abstract: A vibration-damping section with sound absorbing material includes a sound proof panel, sound absorbing material fixed on one surface thereof and vibration damping material stuck on the top surface or the bottom surface of the sound proof panel one surface of the sound absorbing material which is the opposite side of the sound proof panel can be covered with a porous panel, if necessary, and moreover a joint is provided for hanging and connecting sections for closely connecting themselves one another in a width direction.

Abstract: A pre-shaped, self-adhesive vibration-damping member for a deformed portion includes a vibration-damping layer having a contact face that is adapted to be brought into contact with the deformed portion and is shaped in advance such that the contact face matches the shape of the deformed portion, an adhesive layer on the contact face of the vibration-damping layer, and a releasing film of a material that is releasable from the adhesive layer protectively coveting the entire surface of the adhesive layer.

Abstract: A motor mount is described for preventing the transmission of noisy vibration of the motor on vehicle body parts on which the motor is mounted by its motor housing. The motor housing is held by a carrier part that surrounds it. The carrier part is surrounded at a radial distance by a mounting part at least in some areas. The mounting part is connected to the carrier part by an elastic sound-absorbing intermediate layer that is subjected substantially to tensile stresses.

Abstract: A vibration absorbing device for a speaker enclosure is tuned upon installation to the speaker enclosure to achieve maximum attenuation of vibrations in a selected frequency range. The vibration absorber, which includes a series of vibration damping plates separated by spacers, is positioned at varying degrees of overhang on a mounting plate on a panel of the enclosure until attenuation of the desired frequency band is maximized. Then the absorber is secured to the speaker enclosure with an appropriately sized permanent mounting plate.

Abstract: The present invention relates to a vibration damped laminate articles having improved force (torque and/or pressure and/or stress) retention, a method of making one article type and novel tools used to make the one article type. The first laminate comprises at least one layer of damping material between at least two substrate layers. At least one deformation area is present in the laminate wherein the substrate(s) are plastically deformed such that they are closer than non-deformed areas of the substrate and wherein the damping material has less mass than in a non-deformed area of the article; the deformation areas providing the areas of good force retention, for an attachment device attached thereto. The second laminate, which is not deformed, contains an additive of sufficient modulus, diameter and loading, in a vibration damping layer to provide improved force retention.

Abstract: The present invention relates to an apparatus that removes howling phenomena in a video display appliance capable of absorbing and damping vibrations arising from the output of a loudspeaker to remove the howling phenomena produced by the transfer of the vibrations to a cathode-ray tube. The apparatus includes a vibration-absorbing section mounted on the loudspeaker for absorbing vibrations generated and propagated from the loudspeaker due to the output of the loudspeaker, and a vibration-damping section having a predetermined space for receiving the vibration-absorbing section therein. The vibration-damping section disperses and damps the remaining vibrations passing through the vibration-absorbing section in the space.

Abstract: A rain gutter downspout noise attenuation apparatus is provided formed by a section of downspout made of sheet metal, or other suitable material, lined with artificial grass and a fastening screw or clip. The sheet metal, shaped in the form of a 160 degree angle, is designed as such that it easily fits into the base of the downspout, with the curve segment situating in the curve of the elbow.

Abstract: A retaining plate is disposed along and spaced apart by a predetermined distance from the surface of a noise source in an automotive vehicle component so as not to be displaced away from the surface of the noise source. A sheet-like elastic member is compressedly interposed between the noise source and the retaining plate. As a result, the effect of reducing the noise due to vibration is attained without substantially increasing the weight of the automotive vehicle components and without adversely affecting the sealability and other performances required to the components.

Abstract: A vibration attenuating device for loudspeaker enclosures and other mechanical vibrating bodies includes one or more damping plates of viscoelastic material positioned to receive vibration energy transferred from the vibrating body. The vibration energy is transferred away from the speaker enclosure or other body and is dissipated as heat due to the internal molecular structure of the viscoelastic material, suppressing noise normally produced by the vibrating body. In various different embodiments, the vibration damping device includes damping plates shaped or mounted in such a way as to provide for attenuation of a wide band of frequencies of vibration. The damping plates themselves may each have a configuration providing for continuously varying frequency response along the length or circumference of the plate, and there may be included a plurality of different-sized plates, each responding essentially to a different frequency band.

Abstract: An acoustic baffle for reflecting sound waves and rejecting background interference noise for use with a hydrophone array. The baffle utilizes a plurality of lenticular resilient elements embedded in a compliant foam elastomer compound. The embedded elements provide control of overall baffle compliance for submarine applications, particularly for high hydrostatic pressure operation. The resilient members are formed from pairs of resilient lenticular shaped elements which are integrally bonded to a highly damped constrained viscoelastic layer to provide uniform noise reduction performance over a broad frequency range. The pairs of elements are joined at their ends by compliant end caps which provide minimum constraint on the motion of the ends, thus limiting bending stresses in the elements.

Abstract: A vibration attenuating device for loudspeaker enclosures and other mechanical vibrating bodies includes one or more damping plates of viscoelastic material positioned to receive vibration energy transferred from the vibrating body. The vibration energy is transferred away from the speaker enclosure or other body and is dissipated as heat due to the internal molecular structure of the viscoelastic material, suppressing noise normally produced by the vibrating body. In various different embodiments, the vibration damping device includes damping plates shaped or mounted in such a way as to provide for attenuation of a wide band of frequencies of vibration. The damping plates themselves may each have a configuration providing for continuously varying frequency response along the length or circumference of the plate, and there may be included a plurality of different-sized plates, each responding essentially to a different frequency band.

Abstract: A muffler mounting assembly (20) for mounting an elongated muffler apparatus (21) to a vehicle (22) for vibratory isolation thereof. The mounting assembly (20) includes a mounting bracket (23) formed for mounting to the vehicle (22), and a muffler support bracket (25) supportively contacting a periphery of the muffler apparatus (21). A pair of isolation mounting devices (27, 28) couple the support bracket (25) to an end portion of the mounting bracket (23). Each mounting device (27, 28) is positioned at a location between the support bracket (25) and the mounting bracket (23), and at substantially opposite sides of the muffler longitudinal axis (26). Further, each mounting device (27, 28) is substantially aligned in a plane (30) extending through the center of gravity (CG) of the muffler apparatus (21).

Abstract: The invention relates to a driveshaft tube having improved sound deadening properties. This benefit is achieved by coating the inner cylindrical surface of the driveshaft tube with a sound deadening material. Preferably the coating material has a density of at least about 0.8 g/cc. A preferred coating material is a urethane elastomer. A coating between 0.010 inch (0.025 cm) and 0.125 inch (0.308 cm) thick is preferred. In the method for forming the driveshaft tube, preferably the coating material is applied as a liquid and allowed to harden. A preferred application method involves spray coating the inner cylindrical surface of the driveshaft tube. The end portions of the driveshaft tube are left uncoated to avoid the end yoke welds.

Abstract: A resonance absorber for the damping of structure-borne vibrations has a number of freely swinging slats with different resonance frequencies. The slats are arranged on a common base which can be connected with a body to be damped, and are constructed as double slats comprising a damping coating which is in each case squeezed between the two slats elements.

Abstract: An acoustic barrier for mounting to a barrier wall, such as a barrier wall between an engine compartment and a passenger compartment of a vehicle. The barrier wall has multiple indentations forming an uneven surface. The acoustic barrier comprises a decoupling layer and a mass layer. The mass layer has a series of projections formed on a rear surface, which coincide with the indentations of the barrier. When the decoupling layer is mounted to the rear wall of the mass layer, the projections alter the shape of the decoupling layer to conform with the shape of the barrier layer.

Abstract: A passive damping mechanism for a panel member in which a bonding layer is disposed on each side of the panel, a damping layer is disposed on each of the two bonding layers, and a constraining layer is disposed on each of the two damping layers. Each of the above-mentioned layers is coextensive with the respective panel surfaces to which it is attached. The bonding layers are preferably made of an aramid fiber material. The damping layers are preferably made of a viscoelastic material. The constraining layers are preferably made of an aluminum-graphite metal matrix composite material. In addition, the coefficient of thermal expansion of each bonding layer should match well with that of each constraining layer.

Abstract: A Vibration Isolation Module (VIM) for a towed acoustic streamer includes cylindrical masses attached at regular spacing to a central core of viscoelastic damping material, which may be extruded over a snubbed elastic strength member. Further snubbed elastic strength members may be attached around the outer diameter of the masses. Viscous "dash-pot" type dampers are installed within the masses. The space between the masses is filled with open cell plastic foam, around which is wrapped a layer of power and data cables. A jacket of damped thermoplastic is extruded over the cable layer and caps containing a fluid filling valve are attached at each end of the module, and the interior void is filled with a low density, high viscosity fluid. The "dash-pot" type dampers can be replaced by a stocking which, under extension, compresses the foam and forces fluid through pores of the foam, thus simulating the viscous damping of the "dash-pot" type dampers.

Abstract: In order to obtain optimum absorption and compensation of relative movements in an exhaust gas system while at the same time avoiding a transmission of movement and the occurrence of a resonance phenomena, a conduit element is proposed having a bellows and a metallic braided or knit jacket. The bellows is fashioned as a highly flexible bellows with an all around absorption of movement. The jacket is applied to the bellows so that the jacket solely follows substantially the wave crests of the bellows.

Abstract: The invention relates to an acoustic insulation screen. The screen comprises a cushion (5) consisting of a flexible bag (4) inflated with a gas under pressure and allowing the gas to flow freely inside the bag, said bag being selected so as not to transmit vibration energy from one point of the bag to another, and the gas being selected from gases in which the speed of sound is greater than the speed of sound in the air. The invention applies particularly to the protection of the payload compartment in a launcher.