Abstract: A rotatable machine component with a ring of resilient material secured to it in the vicinity of at least one axially projecting collar. The collar has a continuous annular groove around it that cuts into its contour radially, and the ring is secured in the groove just by snapping into it. The ring and the rotatable component rest loosely against each other, when the component is not rotating, without internal tension in the ring.

Abstract: A manifold converter comprises a housing constructed of two metal shells welded at their mating edges; a catalyzer carrier unit installed in the housing in a manner to define therein upstream and downstream portions with respect to the catalyzer carrier unit; and a sealing mat disposed between the catalyzer carrier unit and the housing to achieve a hermetical sealing therebetween. A binding structure is further employed for binding a given portion of the housing where the sealing mat is located. With this binding structure, undesired permanent expansion of the housing caused by the inevitable thermal expansion is suppressed or at least minimized.

Abstract: An apparatus (32) for modifying the percussive sound emanating from a drum (10) includes a hollow skirt (34) having a first end (36) and a second end (38) that define openings (40) and (42) that are in opposition and communication with each other. The skirt (34) is generally configured to be conical or quasi-conical in shape, the first end (36) forming the base of the conical shape and the second end (38) forming the vertex. The opening (42) is large enough for a stand (24) upon which the drum (10) is mounted to pass through. The material or materials selected for the skirt (34) depends upon the desired tonal results of the apparatus.

Abstract: There is presented an underwater vehicle tailcone assembly including a ford flange, a first tubular sheath extending rearwardly from the forward flange, and elastomer material bonded to inner and outer surfaces of the first sheath to form a forward chamber wall. The assembly further includes an aft flange, a second tubular sheath extending forwardly from the aft flange, and elastomer material bonded to inner and outer surfaces of the second sheath to form an aft chamber wall. The assembly still further includes a rigid housing wall disposed between a rearward end of the forward chamber wall and a forward end of the aft chamber wall. The forward chamber wall, the housing wall, and the aft chamber wall form a continuous tailcone wall from a forward edge of the forward flange to a rearward edge of the aft flange.

Abstract: A mute for stringed instruments such as banjos, guitars, and the like which allows the volume of the sound generated by plucking the strings to be varied without changing the pitch of the instrument. This device comprises a small, elongated cloth bag filled with tiny metallic balls. The bag is sufficiently long that when it is properly mounted on the bridge of the instrument, the bag extends past the points where the two outermost strings cross the bridge, the two outermost strings being disposed proximate opposite ends of the bridge. In use, the beg is mounted partially on the upper edge of the bridge and partially on the strings. The degree of muting, as well as the duration of individual notes once played, varies with the position of the bag on the bridge. The pitch of the strings, however, does not vary.

Abstract: The present invention relates to acoustic and vibration attenuation compoe material, particularly to damping tiles of the Type VI class 1, suitable for use in aircraft, ship and submarine applications, that is inexpensive, does not result in an unacceptable weight penalty, and is conformable-in-place to complex curvatures. The present acoustic and vibration attenuation composite comprises a constraining layer of at least one ply of graphite fabric together with curable phenolic resin bonded to a viscoelastic layer.

Abstract: A method and article for damping acoustic energy caused vibrations comprises forming a damping surface comprising an alloy containing from about 13.5 to about 24.5 atom percent tin with the balance being essentially titanium or a titanium-chromium alloy containing from about 52 to about 56 atom percent chromium, about 8 to about 12 atom percent aluminum, and the balance essentially titanium.

Abstract: A vibration damping support stand for a loud speaker enclosure system wherein the enclosure defines bottom and top and opposite side walls. A framework includes a pair of oppositely-facing upstanding parallel standards movable toward and away from each other. A horizontally-extending inwardly-facing support arm projects inwardly from each standard toward the other arm for jointly supporting a base upon which the bottom wall of the enclosure may be seated. A side pad is mounted on the inboard face of each standard for embracing a respective enclosure side wall. An upper pad is adapted for bearing upon the enclosure top wall. Resilient tensioners are strategically located between each standard and the upper pad and between each standard and the base. The arrangement accomplishes reducing and draining off of any enclosure vibrations and allows speaker performance which is relatively free of confusing spurious resonances.

Abstract: An acoustic damping device having a hollow cone partially filled with an acoustic damping medium. The cone is composed of solid material such as wood. The acoustic damping medium can be a particulate solid, such as metal powder, or a liquid. The acoustic damping device is placed between a speaker and a speaker platform to reduce the amount of vibrational interference that reaches the speaker.

Abstract: An elongate chain member having first and second ends is arranged for biased securement relative to the first and second ends for mounting peripherally about a brake rotor during a training procedure to dampen vibrations and audible noise. The invention is arranged to further include vibration dampener blocks within individual links of the chain member.

Abstract: A double-wall hollow body comprises an inner hollow body and a cooperating outer hollow body. The outer hollow body is frictionally attached to the inner hollow body, and is radially spaced from the inner body so that an annular space is formed between the two bodies. Acoustic-damping insulating material is contained within the annular space, and forms an interlayer between the inner and outer bodies. An end of the double-wall hollow body is formed by respective ends of the inner and outer hollow bodies that rest directly against each other without insulating material. The inner hollow body is separated over an entire circumference from the outer hollow body by the insulating interlayer. Various methods of manufacturing the foregoing double-wall hollow body are also described. For instance, to apply the insulating material to the inner hollow body, such body may be heated and then rolled into the insulating material.

Abstract: Material for providing acoustic protection against a source of noise, the material comprising a substrate and resonators, wherein said resonators formed on the substrate are constituted by thread-like and/or area-occupying composite elements whose structural characteristics (density, modulus of elasticity, shear modulus, damping factor, piezoelectric factor, etc. ...) and whose shape and/or size are selected to associate a predetermined resonant frequency with each resonator, and also to absorb the sound pressure energy from the noise source at said resonant frequency and dissipate it in the form of mechanical heat energy and/or electrical energy. The invention also relates to apparatus constituted by a wall including at least one layer of the above material.

Abstract: A vibration damping assembly incorporating an attenuating body formed from viscoelastic material is disclosed. The body may, in a preferred embodiment, be made up of a plurality of plates stacked together and separated with spacers. The viscoelastic material is preferably high impact polystyrene. The damping system is advantageously mounted on an enclosure panel of a loudspeaker to attenuate the vibrations of the panel, thereby minimizing audio signals which usually emanate therefrom and interfere with the desired speaker output.

Abstract: A drum damper for reducing drum overtones comprises a soft cushion (11) attached to a dense foam body (10). Anchors (16) attached to the inside of a drum by existing screws (23) allow a fastening strap (15) to hold the foam body, which has a sloped rear portion (12), securely inside the drum. The body urges the cushion in compression against the drum heat (22). The strap can be adjusted to control the amount of force it exerts against the sloped rear portion so as to control the force the body exerts against the cushion, and hence the cushion against the drum head. The tighter the cushion is compressed against the drum head, the greater the overtone reduction.

Abstract: A two-layer, vibration-absorbing and anti-corrosive, abrasion-resistant coating for rigid substrates, in particular for sheet metals in the underbody region of motor vehicles, for reducing the noise caused by impacting particles, comprises an inner layer, facing the substrate, of a polymer A and a plasticizer P.sub.1, and a covering layer of a polymer B and a plasticizer P.sub.2, such that either the polymers A and B have a different chemical composition and the polymer A is essentially incompatible with the plasticizer P.sub.2 and the polymer B is essentially incompatible with the plasticizer P.sub.1, or both layers contain essentially the same concentration of one plasticizer (P.sub.1 =P.sub.2), so that there is no risk of one layer being impaired by the plasticizer from the other layer.

Abstract: A vibration damper includes a suspended mass connected to a pipeline or similar structural member by a support ring and an assembly of interconnected, generally cylindrical damper members formed of an elastomer material suitable to be stressed in shear. The damper assembly is of modular construction so that the damper can be easily tuned to particular frequency and amplitude conditions of different pipes and spans, respectively.

Abstract: A muffler for an air-cooling system used for channeling air for cooling an electric motor comprises a housing mounted on the electric motor and formed with an air inlet; and an air outlet and an air passage extending between and connecting the inlet and the outlet. Air from outside the housing employed to cool the motor enters through the inlet, flows through the passage and exits through the outlet. Noise having a spectrum of frequencies including a relatively low main discrete frequency, which corresponds to a relatively long wave-length, and a plurality of higher frequencies is generated in the cooling air during operation of the motor and its cooling system. A baffle is positioned within the housing adjacent to the outlet to interrupt lines of sight from the air passage to the outside of the housing. The housing and the baffle are made of a metal or plastic and have sufficient mass to attenuate the higher frequencies of the noise spectrum to a substantial degree.

Abstract: A rotary machine having a machine body and a cover covering an opening of the body. The cover is fixed to the body by an improved vibration-absorbent structure. A peripheral edge of the cover which is adjacent to the body has plate-spring-shaped mounting brackets whose distal ends project from the edge. The end of the machine body which is adjacent to the cover has mounting portions that are grooves or holes. The bracket distal ends are inserted into the mounting portions through rubber vibration insulating members. With the structure, the cover is assembled at improved efficiency and is restrained from vibration.

Abstract: The present noise reduction system provides a tool and a method to dampen the vibration of sheet material such as a panel, a metal sheet or a skin while performing a manufacturing operation on it, for instance riveting, drilling, etc. This noise reducing tool is held in place by vacuum and thus avoids the disadvantages associated with gluing and mechanical or magnetic fixing devices. This noise reducing tool includes a flexible pad made of a metal back sheet with a vibration damping sheet adhered to it and having an air seal surrounding the damping sheet such that the pad is held against the panel by action of a vacuum intermediate the damping sheet and the panel.

Abstract: A damping treatment for bodies where the temperature may rise above 150.degree. C. consists of a number of stand-off cantilever, sandwich type dampers (1), consisting of a layer of viso-elastic material (3) sandwich between two rigid metal plates (4, 5), which are attached to a support (2) that can be attached to the body (7). The support (2) is thermally isolated from the body (7) and is positioned at a position of high amplitude of a radiating frequency that is to be reduced.

Abstract: A seismic isolator for absorbing earthquake vibrations is provided which comprises a laminated member arranged to be interposed between a structure and a foundation, the laminated member comprising thin steel sheets having concavities and convexities extending in a single direction, flexible sheets stacked alternately with the steel sheets, and upper and lower end plates, all these sheets and plates being unitarily and fixedly bonded together. The upper and lower end plates are fixed to the structure and the foundation, respectively, in such a manner that the concavities and convexities extend in a direction in which earthquake vibrations are to be isolated from the structure. The seismic isolator of the present invention is particularly suitable for use with a bridge.

Abstract: An intake manifold wherein separately produced sections of metallic or plastic material have neighboring surfaces defining a chamber which is adjacent the cavity of the manifold and is filled with a vulcanized elastomeric material which is bonded to the neighboring surfaces by a coupling agent, such as silane. The elastomeric material can be silicon rubber, nitryl rubber or polyacrylate rubber. The neighboring surfaces of the sections can form a tongue-and-groove connection which is adjacent the cavity of the manifold and is also adjacent the elastomeric material.

Abstract: Toilet bowls made of porcelain are conventionally disposed directly on the floor and/or attached thereto through rigid connections. When the toilet is used, acoustic vibratons are therefore transmitted from the bowl to the floor and spread all over the dwelling. In the case of a multiple unit residential building, the acoustic vibrations even reach the surrounding residential units and disturb their occupants. To overcome this drawback, the acoustically insulating method proposes to insert a strip of rubber foam between the base of the bowl and the floor and to attach the toilet bowl to the floor through a pair of fasteners each including a rubber link, whereby no acoustic short circuit is established between the bowl and floor to thereby considerably reduce the transmission of acoustic vibrations to the floor.

Abstract: A vibration-controlling member is made by containing a flake-shaped powdery substance having vibration controlling action in a retainer adhered to one surface of a surface sheet. Any external shock imparted to the member is subjected to the vibration controlling action due to a grain boundary friction of the powdery substance.

Abstract: A tower-type speaker cabinet assembly for plural speakers of a high fidelity audio system, including a vertically elongated tower cabinet having a pair of front wall segments adjacent the uppermost and lowermost ends of the tower speaker cabinet and an intermediate forwardly opening cavity extending between the upper and lower front wall segments, a pair of vertically spaced large subwoofer speakers in the respective upper and lower front wall segments with associated inner cabinets forming sound boxes therefor, and a swivelled movable center subcabinet spanning the vertical distance between said front wall segments, having a woofer, a mid-bass speaker and a pair of tweeters carried by a front wall portion of the center subcabinet in vertical alignment. The subcabinet has a range of swivel movement horizontally through predetermined angles about a vertical axis located a short distance rearwardly from the front wall of the swivelled subcabinet.

Abstract: A propeller thruster installation includes a propeller unit rigidly supported in an inner tunnel tube which in its turn is elastically coaxially supported in an outer tunnel tube which is rigidly secured to the hull of a ship. In order to reduce the transmission of noise and vibrations from the propeller unit to the interior of the ship an annulus between the outer and inner tunnel tubes is filled with, a continuously maintained "bubble curtain" of air.

Abstract: A mount capable of being pressed into an installed position in a hole in a plate. The mount has inner and outer concentric annular elements connected together by an intermediate flexible thermoplastic elastomeric web. The outer annular element has a peripheral groove which receives the plate and a deflectable wall with a chamfered outer surface and a series of slots. The flexible web permits the inner element to vibrate with respect to the plate and thereby isolate an item from the plate.

Abstract: To manufacture an anechoic coating which prevents a wall from reflecting acoustic waves, the wall is coated with an elastic material of low compressibility, which is highly absorbent under shear stresses, and then with a highly compressible layer of material. A set of plates covers the second layer and vibrates under the effect of the acoustic waves. Rods fixed to these plates transmit these vibrations to the first layer which is thus subjected to shear stresses and dissipates the energy of the vibrations, thus making it possible to avoid the sonar detection of submarines.

Abstract: A cover for use with a motor and handle extending from the motor comprising, a soft, resilient, fairly rigid, thermoplastic elastomeric material of one-piece construction. The cover has a first body portion having a sidewall and a dome extending from the sidewall defining a cavity to receive the motor, with the dome being spaced from the motor to define a chamber between said dome and motor which serves as a muffler to reduce noise. The cover has a hollow second body portion extending from the first body portion and having a bore to receive the handle.

Abstract: A base for a loudspeaker enclosure is formed of a lower base disk, an upper support disk and an interposed spacer element which together define an internal hollow space to which structure-borne sound is transmitted. The area of contact between the spacer element and the disks is relatively small is comparison to the area of the disks which defines the hollow space at top and bottom sides thereof. In a preferred embodiment, the disks are formed of a sound-insulating material, preferably rubber, and the spacer element is a spacer ring that peripherally defines the hollow space. Also, a bracing foot, preferably of an inverted frustoconical shape, may be carried upon the upper support disk, for which purpose a support plate is centrally mounted thereon.

Abstract: A rotary disc for a disc brake assembly in which a pair of nodes or antinodes in all the vibration modes are fixed to rotate integrally with the rotary disc, thereby to prevent a standing vibration mode of all the diametric nodes. A pair of diametrically opposed outer peripheral portions of the disc are made heavier and more rigid than the remaining outer peripheral portions of the disc.

Abstract: A tuned, convoluted, stainless steel conduit assembly is especially well adapted for use in hostile environments subject to vibrations which bring on fatigue failures. To prevent the conduit from having a uniform resonance throughout its length, the convolutions have a variable wall thickness. One way this variable wall thickness may be achieved is by forming the conduit walls by wrapping stainless steel tape in successive layers to form a multiple layered wall. The width of the tape may be such that some convolutions have more layers than other neighboring convolutions. A stainless steel sleeve or stocking loosely fits over the conduit and is clamped by one or more tuning bands onto the conduit to prevent vibration of the conduit at that clamped location.

Abstract: An arrangement for mounting a motor blower assembly in a canister vacuum cleaner uses a pair of resilient rubber rings, one each on the front and rear of the assembly, to isolate the motor from the vacuum cleaner housing. The front ring goes over the front of the fan casing and is trapped within the housing, while the rear of the motor has attached thereto an adaptor which fits within the complementarily shaped rear rubber ring. This rear rubber ring in turn fits within a complementarily shaped motor support, which is attached to a support abutment within the housing. In order to accommodate different size motors within the same housing and utilize the same mounting components, the support abutment is pre-drilled at various locations to accommodate the different size motors. Thus, the only fixed attachment to the housing is the rear support, which is isolated from the motor blower assembly by the rear rubber ring.

Abstract: Acoustic damping is provided by a dimensionally-recoverable article, either in single layer or constrained-layer form. The single layer, or the damping layer of a constrained-layer article, comprises a mixture of a damping component (generally having a high tangent delta value) and a hold-out component (generally having a significant crystallinity).

Abstract: An assembly for mounting an exhaust system and for connecting inlet means of said exhaust system to exhaust gas outlet means of an exhaust gas source structure of an internal combustion engine comprises a holder for carrying the exhaust system, metal bellows means fixed to the holder and secured to said exhaust gas source structure and connecting said exhaust gas outlet means to said inlet means, and a plurality of axial vibration dampers. In order to keep the deformations of the metal bellows within permissible limits and permit large forces to be taken up, six axial vibration dampers are provided, which are arranged around one or more metal bellows, only three of said vibration dampers have axes disposed in a plane, only two of said three axes are parallel to each other and the axes of the three other dampers intersect said plane and are parallel to each other or constitute a tripod having an apex spaced from said plane.

Abstract: A tuned convoluted conduit assembly is especially well adapted for use in hostile environments subject to vibrations which bring on fatigue failures. To prevent the conduit from having a uniform resonance throughout its length, the convolutions have a variable wall thickness. One way this variable wall thickness may be achieved is by forming the conduit walls by wrapping tape in successive layers to form a multiple layered wall. The width of the tape may be such that each alternate convolution has more layers than its two adjacent neighboring convolutions. A sleeve or stocking loosely fits over the conduit and is clamped by a band onto the conduit to prevent vibration of the conduit at that clamped location.

Abstract: A drive shaft has a noise absorber consisting of a rubber cup-shaped element inserted in the drive shaft and a plastic insert that presses the cup-shaped element against the interior wall against the drive shaft.

Abstract: A combination skid resistant and vibration dampening device formed from rubber-like material having a high coefficient of friction which is integrally bonded to cellular foam type material which has high impact absorption capacity.

Abstract: A vibration isolator particularly suited to isolating a closed cycle refrigerator in a cryopump includes a bellows having o-rings made of vibration damping material secured between the corragations of the bellows. A soft damping material maintains a low spring constant and also dampens all frequencies transmitted into the isolator.

Abstract: A dynamic absorber for a motor vehicle comprises the engine, radiator, air conditioning condenser and electric radiator fan all supported on a module support to form a module. The module is mounted on the vehicle body with elastic mounts with the center of gravity of the module located approximately at the anti-node of the vehicle body. Both the module and the idle speed of the engine are tuned to the first major beaming mode of the vehicle body.

Abstract: Acoustic noises are suppressed in a large format drafting plotter (10) utilizing a paper drive motor (22) mechanically coupled to a paper drive shaft (20) by a geared timing belt (26) from the motor to a pulley (24) on the drive shaft by suitably modifying the pulley. The pulley is modified by enlarging the drive shaft hole (38) in the center thereof so as to provide slip-mounting of the pulley on the drive shaft. A winged clamp (30) is provided, mounted on the pulley, and having a central portion (34) having an opening (36) therethrough for engaging a portion of the drive shaft and a tightening screw (40) for securing the winged clamp to the drive shaft. The winged clamp also has two opposed extensions (42), which are each maintained between a pair of bosses (44) on the outside surface (24a) of the pulley, and isolated therefrom by a pair of isolator pads (32) comprising a compliant material.

Abstract: Two arcuate panel sections having a dampening layer between two honeycomb layers form a module which is mounted in multiple elastomeric isolators located within channel members. Support brackets attached to the interior of the aircraft skin support the channels in the overhead area and along the port and starboard deck edge. The module is thereby spaced apart from the aircraft frame. There is a resulting diminution of acoustic transmission from the aircraft frame to its interior passenger area.

Abstract: A spring element comprises an elastomer block (5) interspersed with at least two sets of cylindrical or prismatic channels (1) which in turn intersect cavities (2) formed in the elastomer block (5), the greatest inside cross-section of which cavities in the plane located at right angles to the channel axis is greater than the cross-section of the channels in that plane, said sets of channels mutually crossing at different levels in space without mutually intersecting. By virtue of this mode of interspersing the elastomer spring element with cavities, an optimal distribution of compressive stresses in the spring element combined with an optimum acoustic damping are achieved.

Abstract: In a body subject to a cyclic energy of such a nature as to cause the body to mechanically vibrate with a principal motion in a first direction, a dry friction damper has a first sliding element fixed to the body, the first sliding element having a first rigid dry sliding surface extending in a second direction having a component perpendicular to the first direction. A second stationary element has a second rigid dry sliding surface extending in the second direction. A normal force is applied between the first and second surfaces, resulting in damping of vibrations by dry friction damping.

Abstract: A vacuum cleaner hose comprises alternating height corrugations which break up airflow and reduce or eliminate whistle during vacuum cleaner operation. The hose likewise provides a high degree of flexibility, crush and kink resistance, and returnability back to its original shape. The hose may be formed of a single non-reinforced member by an extrusion blow-molding process. In one embodiment, the widths of the corrugations alternate with the heights.

Abstract: The invention provides a vibration damping system in which a vibration damper made of materials which have different degrees of plastic deformation and which are integrally or unitarily joined is interposed between an equipment to be vibration-damped and a support for supporting the equipment.

Abstract: A conduit is adapted for use in an environment where it is subjected to excessive vibration. An example of such an environment is the exhaust system on an engine. To preclude material fatigue responsive to such vibration, successive convolutions are varied in height, thickness, slope, spacing, or a combination thereof. Hence, each incremental length of the conduit has a different resonant frequency as compared to the resonance frequency of its adjacent neighboring incremental lengths so that there is no overall high amplitude resonance along the entire length of the conduit, taken as a whole. On the other hand, once the resonance is sufficient to provide self-damping, efforts should be made to maximize the uniformity of vibration response so that bending forces will not be concentrated in one area of the conduit.

Abstract: An annular element is disposed within an outer tubular member of an insulator device in a manner to surround a recessed elastomeric body interposed between the outer tubular member and an inner tubular member. A channel formed in the outer periphery of the annular element is closed by the outer tubular member to define a passage which fluidly intercommunicates chambers defined by the recesses formed in the elastomeric body. The channel is sufficiently long and robust as to ensure the desired vibration damping and working life of the unit.

Abstract: A vibration isolating pipe wherein slits are cut along the axis of the pipe and the friction of the slit surfaces absorb vibrations. Applications are made to a motorcycle body frame and a motorcycle exhaust pipe.

Abstract: A ring damper for reducing vibration and structureborne noise propagation piping systems, comprising a metal ring that is clamped circumferentially around the outer surface of the pipe or duct, said ring defining an annular chamber or cavity that is stuffed with a combination of damping materials.