Abstract: A vibration-damped machine and method including beam being capable of gross movements in space relative to a stationary frame, means including a motor for causing the beam's gross movements; the gross movements tending to induce vibration into the beam, sensors for providing a signal representative of the induced beam vibration, an linear-acting inertial actuator mounted to the beam, and control means for receiving the signal and generating an output signal to actively drive the linear-acting inertial actuator at the appropriate phase, frequency and magnitude to damp induced beam vibrations. Embodiments of the vibration-damped machine are illustrated for a gantry robot, a horizontal machining center, an adhesive dispenser and a pivoting robot. The linear-acting inertial actuator is preferably controlled according to an inertial damping control method where the actuator is forced to behave as a damper attached to ground.

Abstract: A vibration damper little depending on temperature, capable of damping plural resonance vibrations over a wide frequency region as well as damping a specific frequency vibration is provided. The vibration damper comprises a housing formed of a rigid material, having an internal space and fixed to a vibration transmitting member, an elastic body inserted in the internal space not bonded thereto with a gap in a direction of vibration of the housing, and a weight integrally supported by the elastic body so as not to touch the housing. The elastic body and the weight form a dynamic damper.

Abstract: A wire rope isolator having a pair of opposed mounting blocks, each having parallel holes formed therein so that the holes in one block are perpendicular to holes in the second block. One block contains two parallel holes passing through the block while the second contains three parallel holes, one of which passes through the block and the remaining holes being blind holes passing inwardly from opposite sides of the block. One end of the rope is secured in one blind hole and the rope is threaded through the block in a clover leaf pattern and the opposite end secured in the other blind hole.

Abstract: An active vibration isolator includes a vibration isolation platform on which an object to be isolated from vibration is mounted, an air-spring actuator which supports the vibration isolation platform, the air-spring actuator including a valve, which is subjected to feedback drive, a vibration measurement device which measures vibration of the vibration isolation platform and outputs acceleration and velocity signals, a position measurement device which measures position of the vibration isolation platform and first, second and third feedback loops. The first feedback loop feeds back an output of a force measurement device, which measures a working force applied by the air-spring actuator to the vibration isolation platform, thereby controlling the working force supplied by the air-spring actuator. The second feedback loop has a PI compensator and signals of the vibration measurement device are fed back to an input side of the compensator, for producing damping and spring effects which act upon the platform.

Abstract: The present invention relates to a device for reducing vibration generated on the structure (2) of a rotary-wing aircraft, particularly a helicopter. According to the invention, the device (1A) comprises at least one flapping mass (3) connected to the structure (2), at least one controllable actuating device (5A) capable of causing the flapping mass (3) to flap, and a control unit (UC1) intended to control the actuating device (5A) in such a way that it causes the flapping mass (3) to flap at a frequency and at an amplitude which allows the vibrations to be reduced and minimized.

Abstract: A vibration isolator for isolating a load from a floor. The vibration isolator may have an active isolator assembly that isolates the load in a first direction and a passive isolator assembly that isolates the member in a second direction or directions. The active isolator assembly may include a single actuator that is coaxially aligned with a sensor. The sensor and actuator can be connected to a controller which together provide active isolation of the load. The passive isolator assembly may include a pendulum that is coupled to a dashpot. Providing a system with just one actuator significantly reduces the cost of the vibration isolator with respect to isolators of the prior art.

Abstract: A magnetic particle damper apparatus is provided for damping motion between two relatively movable members. The damper apparatus comprises first and second conductor members each attachable to one of the relatively movable members. The conductor members are disposed with confronting surfaces having a gap therebetween filled with a quantity of magnetic particles. A magnetic element is attached to one of the conductor members, producing magnetic flux which is substantially confined to a magnetic flux path defined by relatively magnetically permeable regions and relatively magnetically non-permeable regions of the conductor members to flow across the gap and through the magnetic particles. The magnetic field causes the magnetic particles along the flux path to adhere to one another and to the confronting surfaces of the conductor members producing a force opposing relative motion between said movable members and dissipating energy when the conductor members move relative to one another.

Abstract: A wire rope isolator includes a wire rope and a pair of mounting blocks. The mounting blocks comprise of a pair of cylindrical elongated end flanges that are connected tangentially to each other by a web that has a thickness that is less than the diameter of the flanges thereby allowing the lower section of each flange to extend downward from each web. A hole passes axially through each flange. Wire rope is passed through each flange hole so that the lower surface of each web faces that of the other web and the pair of flanges of one mounting block are offset 90° to the pair of flanges of the opposing mounting block. Four U-shaped half loops of wire rope, with sufficient slack to impart elastic qualities to the wire rope, are formed. The U-shaped half loops extend outward at angles of about 45° from the mounting blocks in a cloverleaf formation.

Abstract: A vibration isolator is mounted on a floor of an ambulance and includes a lower frame movably mounted on the floor and an upper frame vertically movably mounted on the lower frame via a link mechanism. The vibration isolator also includes a plurality of magnetic springs interposed between the upper and lower frames and each having a plurality of permanent magnets with like magnetic poles opposed to each other. A vertical vibration of the upper frame is restrained by the plurality of magnetic springs, and the front side of the vibration isolator is lifted upon receipt of a forward acceleration.

Abstract: The invention relates to the field of damping in load-carrying members, particularly those load-carrying members that carry a load between a plurality of masses that are subject to induced cyclic distortion or vibration. According to an aspect of the invention, a damped structural member is provided that carries a load between a first mass and a second mass. The damped structural member comprises a load-carrying member that carries the load between the first and second masses, and at least one damping member nested with the load-carrying member. The damping member and the load-carrying member move relative to each other during cyclic distortion of the load-carrying member thereby dissipating distortion energy at a damping interface between the damping member and the load-carrying member. The damping member bears essentially only cyclic loads induced by cyclic bending mode movement of load-carrying member. A method for damping a structural member is also provided.

Abstract: The invention relates to the use of low-density granular fill with a specific gravity less than 1.5, placed in hollow cavities built into turbomachinery blades, vanes, and shafts. The granular fill provides effective damping at lower frequencies than conventional passive damping treatment due to its low bulk compressional sound speed. Selected materials used for the granular fill treatment are chosen for specific turbomachinery needs, including temperature of operation. Rotation speed is also a factor because it induces on the granular material an apparent hydrostatic pressure associated with the centripetal acceleration, and sound speed in granular materials is a function of pressure raised to the power 1/n. Preferred designs for placement of low-density granular material in appendages and shafts are found using an iterative design tool based on the Direct Global Stiffness Matrix method.

Abstract: A fluid mounting (20) for isolating or damping vibration between a vibrating member (21) and a structure (23). In one aspect, the fluid mounting (20) includes inner (22) and outer (24) members, a flexible element (26), first (28) and second (30) operating chambers, a fluid passageway (32) interconnecting operating chambers (28, 30), and a partitionless volume compensator (36) including a compensator chamber (38) separated into a gas-filled portion (40) and a fluid-filled portion (42). Notably, the chamber (38) is devoid of any separating barrier. At least one lock passage (44) interconnects the fluid-filled portion (42) with one of the first and second operating chambers (28, 30), and a working fluid (34). Preferably a bubble trap depression (46) focuses any gas bubbles into the lock passage (44). In another aspect, mounting (20) may include laminated shim construction with sloping profiles thereon to prevent bubble trapping.

Abstract: A vibration isolator for isolating a load from a floor. The vibration isolator may have an active isolator assembly that isolates the load in a first direction and a passive isolator assembly that isolates the member in a second direction or directions. The active isolator assembly may include a single actuator that is coaxially aligned with a sensor. The sensor and actuator can be connected to a controller which together provide active isolation of the load. The passive isolator assembly may include a pendulum that is coupled to a dashpot. Providing a system with just one actuator significantly reduces the cost of the vibration isolator with respect to isolators of the prior art.

Abstract: A passive, multi-axis, highly damped, shock load isolation mount which can serve as a complete one-piece mount, particularly of a spacecraft to its launch vehicle or launch vehicle adaptor structure, or can serve in multiplicity as necessary to provide a complete shock load isolation mounting system. When used as a one-piece mount or used in multitude as a system, the invention provides substantial reduction in the shock load transmission to a payload from its support base for both axial loads and lateral loads. The unique multi-layered, opposed beam, contorted load path flexure design combined with a shear wall type constrained layer damping treatment provides substantial shock load isolation in a durable, reliable, lightweight, and compact form.

Abstract: By a controller 18 which receives signal input from a first sensor 16 for detecting the vibratory state of an object O to be isolated from vibration and from a second sensor 17 for detecting the vibratory state of an intermediate mass element 13, a signal is outputted to a power input portion 12 of a piezoelectric element 11 to cause a voltage variation such that the intermediate mass element 13 vibrates to cancel out the vibrations of the object O in an acting direction.

Abstract: An anti-vibration apparatus is equipped with a plurality of active support legs which support an anti-vibration table and which are able to actively operate to control the motion of the anti-vibration table in a horizontal plane. The apparatus is further equipped with a pressure feedback loop for detecting the internal pressure of an air spring provided in each of the plurality of active support legs and for feeding a signal, which is based on the detected internal pressure of the air spring, back to the control system of the anti-vibration apparatus.

Abstract: A vibration damping apparatus includes a plurality of actuators for removing vibration of a table as an object of vibration damping, a detection device for detecting a vibration status of the table, an acquisition device for acquiring compensation amounts for a plurality of directional elements, from the vibration status detected by the detection device, and an allocation device for allocating an actuator-driving force corresponding to a compensation amount for a predetermined directional element, among the compensation amounts acquired by the acquisition device, to an actuator having a small amount of driving force, allocated based on a compensation amount for another directional element.

Abstract: A foot structure for an apparatus including a two part bolt member and a slide cup. The bolt member first part is fixed to the apparatus and the second part loosely engages the first part, with an elastic member therebetween. The slide cup has, at an upper portion, a recess for slidably supporting an end of the second part of the bolt member, and a lower portion movable on a floor surface.

Abstract: In the manufacture of a pressed-in torsional vibration damper, the contact surfaces of the components arranged concentrically with one another are coated, before the elastomeric spacer ring is inserted, with an adhesive which is then activated by fitting the components together. The adhesive is subsequently cold-cured or catalytically activated.

Abstract: A self-tuning type vibration damping apparatus for damping vibration of a vibration damping target includes a sphere, and a sphere case attached to the vibration damping target to movably accommodate the sphere.

Abstract: Disclosed are methods and apparatuses for varying stiffness and/or damping characteristics of a vibration isolation system based on the machine's control signal which indicates the motion status of at least one movable component of a machine supported by the vibration isolation system. The motion status of the movable component can be monitored via parameters such as the electrical power being injected into the motor of the movable component. More stiffness and/or damping are provided to absorb shocks generated while the movable component accelerates or decelerates and less stiffness and/or damping are provided while the movable component moves at a nominally constant speed or stands still.

Abstract: A device for damping vibration of a vibrating structure, particularly a helicopter cyclic control system, comprises a straight tubular shaft having a metal weight retained within the inside bore of one end, the remainder of the shaft being unweighted, and two elastomeric lined mounting brackets for securing the unweighted portion of the shaft to the vibrating structure, the bracket closest to the unweighted shaft end holding the shaft end with a tighter fit than the other bracket.

Abstract: Undesirable vibrations are controlled in a mechanical structure by confining the vibrations to one or more specified areas of the structure and then dissipating the confined energy by damping. Vibration confinement is achieved using a confinement device which effectively applies both translational and torsional forces to the structure. The strength of the translational and torsional forces, and the position of the confinement device are chosen to select a vibrational energy confinement region. Damping elements are concentrated in the vibration confinement region to dissipate the confined vibrational energy. Judicious selection of the confinement region permits the structure to avoid the transfer of vibrational energy to particularly sensitive portions of the structure, or to direct vibrational energy to a portion of the structure. Optimization procedures are presented for designing structures having optimized placement and selection of the vibration confinement device and damping devices.

Abstract: A damping device is provided for damping relative displacements between first and second structural elements. The device includes a cylinder which is stationary relative to the first structural element and defines two chambers separated by a wall. A fluid is contained within the chambers. A passage is provided to interconnect the two chambers and at least one both-way valve is provided which shuts off the passage. When the pressure in one of the chambers increases due to movement of the structural elements, the passage is opened to enable the fluid to flow from one chamber to the other.

Abstract: A rotation damper with a housing, a rotor which is rotatably mounted in the housing and which, with the housing, forms at least one gap into which a viscous medium is enclosed, and an axle or shaft which is connected to the rotor and which at least at one end projects out from the housing. There is further provided a filler opening, for the viscous medium, which is formed in the housing and which at least over part of its length comprises a uniform circular cross section and a closure element comprising a circular linear sealing edge, the diameter of which is somewhat larger than the inner diameter of the filler opening in the region of the uniform cross section.

Abstract: A Multi-Directional Tuned Vibration Absorber (MDTVA) (23) including a first tuning mass (32) vibrating at a first resonant frequency fn1 along a first axis, a second tuning mass (34) vibrating at the first resonant frequency along said first axis and also at a second resonant frequency fn2 along a second axis, a base member (21), a first spring (35) flexibly interconnected between the base member (21) and the first tuning mass (32), the first spring (35) substantially restricting motion of the first tuning mass (32) to motion along a first axis only, and a second spring (36) flexibly interconnected between the first tuning mass (32) and the second tuning mass (34), the second spring (36) substantially restricting relative motion between the first tuning mass (32) and second tuning mass (34), such that the relative motion of said second tuning mass (34) at said second frequency fn2 is along the second axis which is substantially perpendicular to the first axis.

Abstract: A flexure bearing unit in a linear drive compressor that supports a piston on a yoke for reciprocating movement within a housing includes a plurality of flat discs each provided with a central opening through which extends the piston and a plurality of outer openings receiving parts of the yoke. The flexure bearing is provided with a plurality of first supports each disposed between adjacent flat discs at the outer peripheral portions of the flat discs for supporting opposite sides of the flat discs at the outer peripheral portions of the flat discs. The flexure bearing is also provided with a plurality of second supports each provided between adjacent flat discs at the inner peripheral portions of the flat discs for supporting opposite sides of the flat discs at the inner peripheral portions of the flat discs. The flat discs each include a plurality of spirally extending slits which each possess oppositely located ends.

Abstract: The present invention relates to a device for reducing the vibrations of the rotor of a rotary-wing aircraft, having an oscillating mass (M1), elastically held radially on the hub (4) of the rotor in the vicinity of its axis (X-X) and fixed to an articulated rod (10) substantially longitudinal to said axis (X-X).According to the invention, said device includes:an adjustment oscillating mass (M2), mounted so that it can move on the rod (10) and having an adjustment position for which the frequency of the resonator formed by said oscillating masses (M1, M2) is matched to the frequency of said vibrations; anddrive means (18) for bringing the adjustment oscillating mass (M2) into said adjustment position.

Abstract: A device for the vibration isolation with level control of an object with respect to a base, having a pneumatic spring and a completely mechanically decoupled control loop comprising a position sensor which operates in a contact-free manner, an electronic controller and an electrically controllable flow valve allowing a contact-free level control with adjustable control parameters.

Abstract: A magnetic spring has at least two permanent magnets (2 and 4) spaced from each other in a kinetic mechanism. At the time of input and at the time of output, the geometric dimensions between the two permanent magnets are changed by the kinetic mechanism or an external force. The change in geometric dimensions is converted into a repulsive force in the kinetic mechanism, thereby (1) making the repulsive force from a balanced position of the two permanent magnets greater at the time of output than at the time of input, or (2) deriving a damping term of the magnetic spring to provide nonlinear damping and spring characteristics.

Abstract: A vibration damping arrangement for a gondola of a type having a supporting unit attached to a cable, a hanger suspended from the supporting unit and a carriage suspended from the hanger. A vibration damping device includes an elongated hollow housing. A bottom plate of the housing defines a down-wardly arcuate oscillation track which extends in a direction perpendicular to the cable. A vibration damping body is movably located on the oscillation track such that it can naturally oscillate on the oscillation track in the longitudinal direction of the oscillation track upon vibrations of the carriage. The vibration damping device is located under a seat inside the carriage, suspended from a bottom of the carriage, supported by the hanger above a roof of the carriage or mounted on the roof of the carriage in such a manner that it does not extend beyond width and length of the carriage. The vibration damping device does not substantially occupy a passenger room so that comfortableness is not degraded.

Abstract: A fluid mounting (20) for isolating or damping vibration between a vibrating member (21) and a structure (23). In one aspect, the fluid mounting (20) includes inner (22) and outer (24) members, a flexible element (26), first (28) and second (30) operating chambers, a fluid passageway (32) interconnecting operating chambers (28, 30), and a partitionless volume compensator (36) including a compensator chamber (38) separated into a gas-filled portion (40) and a fluid-filled portion (42). Notably, the chamber (38) is devoid of any separating barrier. At least one lock passage (44) interconnects the fluid-filled portion (42) with one of the first and second operating chambers (28, 30), and a working fluid (34). Preferably a bubble trap depression (46) focuses any gas bubbles into the lock passage (44). In another aspect, mounting (20) may include laminated shim construction with sloping profiles thereon to prevent bubble trapping.

Abstract: A low force actuator that is used in conjunction with semi-active and passive suspension systems to provide for improved suspension and ride control for vehicles, and which overcomes stiction and provides limited active capability. The low force actuator is sized to counter the small, high frequency forces (caused by road input disturbances and stiction effects) that act on, or are transmitted between sprung and unsprung masses of the vehicle. The present invention provides for two low force actuators. The first comprises a proof mass low force electromagnetic actuator that may be connected to either the sprung or unsprung mass. In either configuration the proof mass provides an extra degree of freedom for the suspension system that decouples ride and holding control actions of the vehicle. The second comprises a differential force actuator that uses an electromagnetic actuator to provide a force between the sprung and unsprung masses of the vehicle.

Abstract: A vibration isolation and precision pointing device, and a related method for its operation, for reducing vibrational disturbances on a payload platform, which is subject to vibration transmitted from a base platform and to other possible vibrational disturbances applied directly to the payload itself or to the payload platform. The invention includes a complementary combination of passive isolation and active isolation in parallel between the base and payload platforms, together with a precision positioning system that greatly reduces vibration at very low frequencies. Each isolation device, of which there are three pairs arranged to damp vibration in three axes, includes, in one embodiment, a passive spring to reduce coupling of vibration at higher frequencies and to fulfill a static load bearing function, and an active actuator element, in the form of a voice coil actuator, for applying active compensation over a selected bandwidth of frequencies below that over which passive isolation is most effective.

Abstract: A mechanical stop for a moving body that minimizes bounce of the moving body after the body has hit the stop. The mechanical stop includes a flat plate having a plurality of generally triangular sectors defined by radial slits. The slits or triangular sectors prevent excessively large diaphragm stresses in the material of the plate and also reflect the flexural waves in the plate in such a way that the waves have difficulty returning to the contact area where the moving body has hit the stop and are maximally dissipated by internal friction of the plate. The mechanical stop may include a lever between the moving body and the flat plate to change the effective mass of the moving body, a spring to mediate the impact of the moving body, a relatively rigid support for the lever to minimize moments produced in a base for the flat plate, and straight line plate supports for some or all of the sectors of the flat plate to provide desirable reflections for the flexural waves in the plate.

Abstract: An ETVA (electrically-tunable vibration absorber) has a vibratable mass with a mechanical spring suspension supplemented by an electromagnetic spring simulation that can be adjusted electrically to vary the self-resonant frequency of the vibratable mass and tune it to a disturbing frequency that is to be suppressed. A flux path from the electromagnet traverses an air gap between a pair of oppositely-facing matching magnetic pole arrays, one of which is attached to the vibratable mass while the other pole array is substantially attached to the object structure that is being treated to suppress vibration.

Abstract: A vibration damping and isolation apparatus including a passive damping mechanism and an active enhancement mechanism. The passive damping mechanism operates to dissipate vibratory and shock forces applied to the vibration damping and isolation apparatus. The passive damping mechanism includes first and second spaced damping elements. A first resilient structure connects the first damping element to the second damping element to define a primary fluid chamber between the first and second damping elements. The passive damping mechanism further includes a second resilient structure that defines a secondary fluid chamber which is in fluid communication with the primary fluid chamber via a fluid flow orifice. A fluid fills the primary fluid chamber, the secondary fluid chamber and the fluid flow orifice.

Abstract: In order to meet the demands of simplicity and reliability in active control systems for flexible structures, an inexpensive active truss element and control law has been developed. A decentralized switching control law is used along with a compressible fluid in the truss element in order to dissipate energy during the motion of the structure. However, the energy is not absorbed in the same manner as a conventional viscous damper. The truss element retains its maximum stiffness, but has a resettable nominal unstressed length. Energy is absorbed in the working fluid of the truss element through heat transfer to the environment when the nominal length is reset at the proper switching times. The control law is insensitive to changes in structural parameters such as mass, stiffness, and damping.

Abstract: A damping control system for a stabilizer bar with an electronic shock absorber between a low arm and the stabilizer bar for controlling the rolling of the vehicle. Included are a potentiometer, a vehicle speed sensor, a steering angle sensor, an electronic control unit and a voltage amplifier.

Abstract: Disclosed is a vibration damping and isolation apparatus having a passive damping mechanism. The passive damping mechanism includes an outer tubular member and an inner member. The inner and outer members are linearly movable relative to one another upon application of forces to the damping apparatus. The inner member is spaced from the outer member by a fluid shear gap that is filled with a viscous fluid. Fluid pressure of the viscous fluid remains constant while the viscous fluid dissipates the forces by direct fluid shear upon relative linear movement of the outer and inner members.

Abstract: A seat of a vehicle is connected to the vehicle body by a support linkage that enables movement of the seat. A hydraulic actuator is connected between the seat and the vehicle body to produce motion which counteracts the influence of the vehicle body movement on the seat. An air bag, coupled between the seat and vehicle body, has a variable spring preload to compensate for differing masses placed on the seat. A motion sensor detects movement of the seat and a displacement sensor detects seat displacement. A force sensor detects a force exerted on the actuator by an operator sitting in the seat. A controller responds to the motion and displacement sensors by operating the actuator to nullify effects of the movement of the vehicle body from acting on the seat, and responds to the force sensor by varying the spring preload of the air bag to maintain the force exerted on the actuator to within a defined range.

Abstract: A vibration damping arrangement for a gondola of a type having a supporting unit attached to a cable, a hanger suspended from the supporting unit and a carriage suspended from the hanger. A vibration damping device includes an elongated hollow housing. A bottom plate of the housing defines a downwardly arcuate oscillation track which extends in a direction perpendicular to the cable. A vibration damping body is movably located on the oscillation track such that it can naturally oscillate on the oscillation track in the longitudinal direction of the oscillation track upon vibrations of the carriage. The vibration damping device is located under a seat inside the carriage, suspended from a bottom of the carriage, supported by the hanger above a roof of the carriage or mounted on the roof of the carriage in such a manner that it does not extend beyond width and length of the carriage. The vibration damping device does not substantially occupy a passenger room so that comfortableness is not degraded.

Abstract: A flex-plate tuned vibration absorber (35) including a tuned mass (43) flexibly suspended by one or more flex plates (58). In one aspect the tunable vibration absorber (TVA) (35) is adaptive in that the position of the mass is adaptively moveable with respect to its initial position, thereby effectuating a change in the TVA's resonant frequency. In one embodiment, the tuned mass (43) moves along a rigid frame (53). In another, movement of the mass (43) statically stresses a preferably disc-shaped flexible plate (58) thereby changing its stiffness. Preferably, a reducer (78) gears down the speed of the motor (64). In another aspect, a TVA system includes a base sensor (40) providing a base vibration signal, a mass sensor (38) for providing a vibration signal of the tuned mass (43), and an electronic controller (42) for generating a control signal to the TVA (35). The TVA finds application for absorbing vibration in vibrating structures, such as in aircraft.

Abstract: An isolation coupling which provides for isolation of torsional vibration, from a drive component to a drive component, such as a driven shaft, due to non-constant drive forces. The vibration isolation coupling includes a drive assembly connected to the drive component, and a driven assembly connected to the driven component. The drive assembly and the driven assembly are axially aligned, such as being mounted on the shaft of the drive component for example. A member, having torsional compliability, interconnects the drive assembly to the driven assembly. Accordingly, vibrations imparted to the drive assembly are isolated from the driven assembly by such torsional compliability of the member.

Abstract: A damping mounting structure for use between two members for isolating motion changes which incorporates a plurality of dampers connected between the two members in a closed geometric shape and which uses cross connections between the dampers located on opposite sides of the geometric shape so that translation motion between the two members is damped less than rotational motion between the two members and an accumulator to provide pressurization of the system but to prevent loss of pressure due to slow rotational vibrations, one-way valves are connected between the system and the accumulator to allow fluid flow only from the accumulator to the system and not from the system to the accumulator and pressure relief or burp valves are used to allow short duration fluid flow from system back to the accumulator when a predetermined system over-pressure is exceeded.

Abstract: A new apparatus and method for dynamically absorbing resonant vibration in jet engine blades and other rotating turbomachine components over all engine speeds is disclosed. A distributed pendulum (a pendulum having its axis of motion inside its body instead of at an end) is mounted inside a jet engine blade to function as a centrifugal pendulum. A centrifugal pendulum can be tuned so that its natural frequency linearly tracks the rotational speed of the engine or other turbomachine in which it is mounted and can absorb resonant vibrations from turbomachine components whenever the frequency of a source of vibratory excitation from a so-called speed line of the turbomachine coincides with a resonant frequency of the component. The equations of motion of a distributed pendulum are derived to show that a distributed pendulum small enough to fit inside a turbomachine component can be tuned to track a turbomachine speed line by adjusting its mass distribution about its axis of motion.

Abstract: An active vibration canceler, including a canceler mass that is attached by a spring device to a supported bearing. The canceler mass is movable by a plunger coil arrangement and a permanent magnet so as to result in at least partial suppression of relative movements of the supported bearing in at least one frequency range. The spring device joins the canceler mass and the supported bearing for relative movement in one direction. The spring device includes at least three leaf springs arranged in at least two planes, which leaf springs, in the idle position, extend circumferentially in the same direction.

Abstract: A flexibly-mounted active vibration absorber (AVA) which has a secondary controllable mass M.sub.3. If the passive resonance of mass M.sub.2 of the tuned absorber is insufficient to control the input vibration, a secondary mass M.sub.3 is vibrated at a frequency, amplitude and phase sufficient to make up the deficiency in mass M.sub.2. Many embodiments are described which depict variations on the first spring used for flexibly mounting the AVA, the actuators used to drive the AVA, and the attachment features for attaching to a vibrating member. Further in another aspect, means for counterbalancing the moments produced by the AVA are described.

Abstract: The invention is uniquely "passive-active" in that it brings to bear, sequentially and complementarily, passive vibration control followed by active vibration control. A conventional mount (such as an air mount) is accommodated so as to include, at the mount's foundation-securing plate, at least one motion sensor and at least one vibratory actuator. Each sensor is correlated with an actuator. For each sensor-actuator pair, the electrical feedback loop includes generation by the sensor of a signal resulting from the local vibration of the foundation-securing plate, generation by a processor/controller of a signal derived from the sensor's signal, and exertion upon the foundation-securing plate by the sensor's paired actuator of a vibratory force commanded by the processor/controller's signal. Many preferred embodiments of the inventive apparatus, system and method collocate each sensor with its paired actuator and implement a conventional vibration suppression algorithm involving collocated velocity feedback.

Abstract: A dynamic vibration absorber comprises a movable portion including a movable weight portion, a movable portion magnet assembly provided with a movable inside magnet and a movable outside magnet which are mounted to the movable weight portion through a yoke so as to alternately provide different magnetic poles, a fixed portion fixed to an object to be damped, a fixed portion magnet assembly provided with a fixed portion inside magnet and a fixed portion outside magnet mounted to the fixed portion through a yoke so that the fixed portion magnet assembly has magnetic poles different from those of the movable portion magnet in opposed positions, respectively, and a conductor plate disposed in a gap defined between the fixed portion magnet assembly and the movable portion magnet assembly.