Abstract: A simple-to-construct noise-isolated fastening of an oil sump to a crankcase using an intermediate layer of elastic material. In this concept, the oil sump and crankcase are not connected by screws or bolts, but by spring clips which are lined with soft elastic material and which, in the connected condition, elastically engage shaped connecting flanges of the crankcase and oil sump.

Abstract: A device for damping an oscillatory system is described. The device comprises a first connection member connectable to part of a spring and a second connection member connectable to a surface on which the spring is mounted. One end of a first bearing member is rotatably mounted in the first connection member and the other end is fixed in a mounting block. One end of a second bearing member is rotatably mounted in the block to extend perpendicularly of the first bearing member. The other end of the second bearing member is fixed in part of a planar component which is pivotally connected by a flexible joint to a second planar component. The device is symmetrical about the pivot line so that a third bearing member and a fourth bearing member corresponding to the second and first bearing member, respectively, are provided between the second planar component and the second connection member.

Abstract: A vibration dampening stiffener beam (10, 10') is secured to a panel member, such as an electrical circuit board (12) that is supported at opposed ends. The beam (10, 10') extends across a mid portion of the board (12) whereat displacement of the board caused by vibration is at a maximum. The beam is an "I" beam or an inverted "T" beam. It has a mounting flange (22, 22') which is bonded or otherwise secured to the member (12) which it is to stiffen. An energy absorbing material (30) is placed on the sides of the web (24, 24') of the beam (10, 10"). This material (30) consists of thin metal constraining layers (32) bonded to each other and to the side surfaces of the web by means of a viscoelastic material (34).

Abstract: A hollow sound damping plate is arranged between a transformer core and an internal limiting surface of a transformer tank filled with insulating fluid. At least one compressive-force transmitting spring member (8) is arranged between the front wall (6) and the rear wall (5).

Abstract: The fuselage (cabin) (15) of a propeller (45) driven aircraft (10) is isolated from vibration associated with the wake (46) of the propeller by vibration isolators (50, 55 and 110) in the wing and tail surfaces of the aircraft.

Abstract: Flexible bellows are utilized between two systems, such as a pumping system and a process station, to partially absorb system vibrations and to compensate for misalignment between the systems. It is common practice to either clamp a rigid spacer between flanges of the two systems (FIG. 3B) to separate them from each other, or to maintain the bellows in unsupported relationship between these systems (FIG. 4B). In the former bellows arrangement, the rigid spacer transmits vibratory energy between the two systems and the bellows tends to function as an undamped or underdamped unit that resonates at its own frequency to create additional vibratory energy, transmitted to the systems. In the latter, unsupported bellows arrangement (FIG. 4B), the pressure differential prevalent between the fluid flowing through the bellows and ambient normally causes extension or retraction of the bellows and resulting misalignment problems.

Abstract: A technique for reducing noise generated by transverse vibrations in elongated members comprises the application of a friction element on a surface of the member. The friction element is forced against one or more surfaces of the member by a selected normal force and is provided in a vicinity of maximum distortion of the member when the member undergoes vibrations. A differential movement between the inner surface of the friction element and the outer surface of the member causes heat to be generated which dissipates the energy of such transverse vibrations.

Abstract: A noise-reduction device for a stationary induction apparatus which device comprises a sound insulation panel attached to reinforcing channels provided at the periphery of a tank of the stationary induction apparatus so as to block noises emitted from the outer surface of the tank, a weighty body attached to the sound insulation panel for reducing vibrations of the sound insulation panel and a dynamic damper of which the natural frequency can be adjusted to be made equal to the vibration frequency of the weighty body so as to cancel the vibrations of the weighty body.

Abstract: A speaker stand for supporting a speaker enclosure on the floor comprising a rigid planar member (11) supporting a waffled cushion pad (12) on the top surface with the pad including peaks 17 and valleys 19. Semiresilient rails (13, 14, 15, 16) positioned to the side of said pad support and stabilize the speaker enclosure such that the pad is depressed sufficiently to form air pockets between the pad and speaker enclosure in the areas of the valleys to attenuate vibratory motion and acoustic sound wave transmissions between the speaker and floor.

Abstract: A static induction apparatus including a vessel for containing a main body of the static induction apparatus, a plurality of reinforcing support members secured to side plates of the vessel and a sound reducing structure. The sound reducing structure includes a plurality of sound reducing members supported between the reinforcing support members and each including a sound insulating panel composed of high damping metal plate, a resilient plate formed of thin metal sheet material interposed between the sound insulating panel and the reinforcing members, and a weight member secured to the vicinity of the boundary between the sound insulating panel and the resilient plate.

Abstract: An ultrasonic sound absorbing material capable of operating at high temperatures and pressures, said material comprises a dense, rigid, permeable material such as sintered metal filled with a viscous fluid.

Abstract: Beam dampers comprising a stiff, lightweight, elongate beam and layer of viscoelastic material located along an attachment flange of the beam are disclosed. The flanges of the beam is attached by the layer of viscoelastic material to the skin of a structure whose skin vibrations are to be damped. While a beam having a cross-sectional I-shape is preferred, other cross-sectional shapes can be used, such as L, Z, U and T-shapes. Regardless of their shapes, the beam acts as a constraining element for the viscoelastic attachment layer. The beam is oriented such that it is stiff in a plane transverse to the plane of the skin, resulting in thickness deformation of the layer of viscoelastic material (rather than shear deformation) converting vibration energy into heat.

Abstract: Viscoelastically damped reinforced skin structures wherein a sandwich skin having a relatively thick core is supported by structural elements, such as stringers and frames, are disclosed. In one form (FIG. 1), a main skin (15) is supported by stringers (13) that are in turn supported by frames (11). The skin, stringers and frames are securely attached to one another by any suitable means, such as a bonding adhesive, rivets, bolts, etc. Located between the stringers are core layers (17) formed of honeycomb or foam materials. A first plate (21) overlies each core layer and extends to the flanges of the adjacent stringer. A second plate (25) overlies each adjacent pair of first plates. The core layer is viscoelastically attached (19 and 23a) to the skin and the first plate; and, the first plate is viscoelastically attached (23b, c and 27a, b) to the stringer flanges and to the second plate. Alternatively, a single plate (49, FIG. 3) can overlie the core layers (47) and the stringers (43).

Abstract: The running characteristics of a tire for a wheel are improved to provide a more quiet run, by attaching to an inner and/or outer surface of the tire vibration absorbing elements. Vibration absorbing elements may even be inserted into the tire material itself. The vibration absorbing elements are secured to the tire surface in a force and moment or torque transmitting manner by vulcanization or by a suitable adhesive. A strap may hold the individual absorbing elements together or the elements may form integral parts of the strap which is secured to the tire surface, for example, by a rubber vulcanizing operation. The vibration absorber elements may be secured to an inner tube instead of to the tire.

Abstract: A tuned sound barrier for machines which radiate sound primarily at a few constant, discrete frequencies includes an array of mechanical resonators distributed over the surface of a sound barrier. Each resonator of the array is tuned to present a high mechanical impedance to transmission of mechanical vibration at one of the discrete frequencies emitted by the source machine. The tuned sound barrier may be either a free-standing sound barrier or an attachment to a housing for the machine.

Abstract: This invention relates to an isolator for a large-sized static induction apparatus such as transformer and reactor. The static induction apparatus wherein a sound insulation panel is mounted through an elastic body on a reinforcing channel which is disposed on a side plate of an oil tank receiving a main device of the apparatus therein, is characterized by disposing a looped weight beam near that part of the sound insulation panel on which the elastic body is installed.With such construction, noise can be effectively reduced while imparting a satisfactory supporting strength to the mounting part of the sound insulation panel.

Abstract: A microphone mounting assembly including an elongated tubing, having a mounting flange including a channel for adjustable receiving said tubing, and sand sealingly received in said tubing for providing acoustic-dampening characteristics.

Abstract: A novel method of producing a vibration damping and sound absorbing coating on a rigid substrate is provided in which method a first coating of a viscoelastic material having after gelling a modulus of elasticity of 5.times.10.sup.6 to 5.times.10.sup.8 dynes/cm.sup.2 is sprayed onto the substrate whereafter there is sprayed onto said first coating a second coating of a viscoelastic material having after gelling a modulus of elasticity of 5.times.10.sup.7 to 5.times.10.sup.9 dynes/cm.sup.2, the modulus of elasticity of said second outer coating being at least 10 times greater than that of said first coating.

Abstract: The acoustical radiation from handling empty cans and containers is reduced to sound levels which decrease the risk of hearing damage for exposed personnel by this invention. The invention comprises the temporary use of damping end-caps comprised of viscoelastic material which eliminates metal to metal contact between containers, guides, and cables and which also dissipates vibratory and airborne acoustical energy in the containers, thereby reducing the acoustical radiation.The invention is applicable in particular to canneries and canning operations.

Abstract: The invention relates to a product (1,9) of metal formed with a hole (5,8,17), particularly a rock drill steel, and provided with an element (10,12,14,15,16,18) for damping sound producing waves in the product annoying for the human ear. The sound damping element is arranged in the hole in the product and has a cross section less than the cross section of the hole. The damping element has at least one contact surface loosely arranged relative to the wall of the hole and located between the nodes of the waves so as to create at least one wave damping effect.

Abstract: In a mining machine having a power driven cutter including metallic helical blade means having cutting bit means spaced along the exterior periphery thereof, the improvement which comprises the helical blade means having fixedly secured in surface-to-surface contact therewith energy absorbing layer means for dampening vibrations set up in the metal of the helical blade means when the cutter is in power operated cutting relation so as to materially reduce the operating noise level of the cutter within the mine.

Abstract: According to the invention the damping of vibration on the part of a structural material such as metal or concrete is effected by applying a limited amount of vibration-damping viscoelastic material between the two such structural parts, the vibration-damping material being being applied in lines, points or the like spaced from each other at distances less than one bending wavelength for the highest frequency range to be damped.