Abstract: A semi-active device 20 is provided for damping motion between structures having multi-degrees of freedom. A magnetic field produced by a permanent magnet, a coil, or a combination thereof, change the rheological properties of an MR fluid 40 to effectively lock up the components and the structures to which they are attached to serve as a brake or damper of the associated compound motion. A system 21 employing the MR devices 20 includes a motion detection sensor 15 and a controller 19 to actuate the MR devices 20 when a predetermined motion threshold is exceeded.

Abstract: An adjustable damper 12 for providing surface effect damping of a first member 10 when moving relative to a second member 20 and providing means for user operated locking of said first member 10 relative to said second member 20 at an infinite number of positions. The damper 12 is particularly useful for locking a chair back in place relative to a chair seat and providing damping of the rotation of the chair back when not locked. This allows the chair back to return to its desired position relative to the seat at a controlled rotational rate. The damper 12 operates by compressing first plate 40 and second plate 50 against elastomers 36A and 36B such that center plate 30 is restrained from rotation relative to plates 40 and 50. A secondary surface effect damping element provides damping when the primary damping element is unlocked. Pin 38 rides in slot 32 and indents the periphery 34 of elastomer 36C bonded to the periphery of slot 32 to provide damping.

Abstract: A waveform generator (20) for generating an analog wave which is synchronized with a signal from an input source (22). The waveform generator (20) includes a phase-locked loop (24) for receiving an input source signal and multiplying said signal by a multiplier. The multiplied square wave signal is then provided to a frequency divider (28) and to a first clock input (39) of a first switched-capacitor filter (29). The frequency divider (28) outputs a divided output signal that is received as an input to the phase-locked loop (25) and by the first switched-capacitor filter (35). As a result, the first switched-capacitor filter (29) outputs a first analog wave of a constant amplitude which is phase synchronized with the input source signal. This waveform generator (20) allows the 3 dB point of the filter to move as the input frequency changes.

Abstract: An active isolator with a closed-loop feedback control system which uses an actuator in parallel spring relation to a static load spring to control the dynamic vibration transmitted from a vibrating device over a broad band frequency range. A collocated sensor is installed to sense the vibration of the isolated element and is amplified and fed, filtered and amplified again, reversed in sign and fed directly into the actuator. No external synchronizing signal or processor is needed. This simple active control is practical only where the combined series dynamic stiffness of the structure and vibrating body is much less than or much greater than the active mount's dynamic stiffness.

Abstract: A fluid mount (20) provides a flexible connection and fluid effects such as damping and/or fluid inertia for a supported member (22) attached to a supporting member (24) in a singular and unitary package. The fluid mount (20) includes a beam (34) and a laminated elastomer and shim construction bonded thereto, defining variable volume fluid chambers (44, 46, 48, 50) and interconnecting fluid passageways (52, 54). Fluid effects are provided in both a radial translational mode (loading at R) and a rotational mode (loading at T) to suppress vibrations of the supported member (22).

Abstract: A variable shock absorber assembly of the adaptive or semi-active type or an active actuator wherein the actuator, sensors, electronic controller and valving are integral to and integrated into one assembly and comprise one compact integral unit. Feedback control provides a signal proportional to and indicative of the actuator position and velocity. The compact system is temperature compensated by incorporating temperature sensors into the integrated assembly. The integrated system also provides diagnostics integral to the assembly and an LED mounted on the assembly for providing a visual indication of system condition.

Abstract: Three embodiments of a shock-isolating caster. A surface-effect damper engages at least one of a wheel element and an intermediate structural member to dampen vibration and shock loads which would otherwise be transmitted from the wheel element through the intermediate structure and mounting member to the equipment supporting cart. A first embodiment positions the damper between an outer wheel rim and an inner wheel hub. Second and third embodiments mount the wheel on a pivotable arm and dampen the movement of the arm. Capability to adjust damping levels is provided.

Abstract: A threadable dental floss (20) is shown in FIG. 3A for cleaning of a user's teeth when said user is wearing braces, bridgework, or the like. The threadable dental floss (20) includes a strand having a first end (26) and second end (26') and a semi-rigid threader (24 and 24') including a curvature formed substantially along its whole length (L'), integrally bonded to and attached to the strand member (22). The semi-rigid threader (24) preferably is made from low friction plastic in an injection molding process. Preferably, multiple sections of the threadable floss are interconnected in a chain-like fashion and are unwound from a dispenser including a spool (FIG. 3B). The user, without having to cut the strand (22), can separate a ready-to-use section of threadable floss (20) with an included curved threader section by simply exerting a small tensile force (2 pounds or less) on the floss chain.

Abstract: A control method for semi-active damper (32) which oscillates in real time (at the frequency of the moving member (22) motion or higher) between a high-damping On state and a low-damping Off state wherein the On and Off damping states are selected by the driver via a driver selectable switch (60) and overridden when the absolute velocity differential across the suspended body exceeds a threshold value and the signs are opposite. Damping bands can be set to a luxury, touring, or sport mode via the driver selectable switch (60). This system provides driver selectable ride feel and yet controls excessive roll and pitch due to vehicle maneuvers, braking, and acceleration by overriding the driver selectable setting whenever the absolute velocity differential threshold setting is exceeded and the directional signs are different. When the threshold is exceeded and the signs are opposed, the null band is adjusted to a narrower setting to initiate control of the damper.

Abstract: A hydraulic mounting system for mounting a first body relative to a second body, such as a vehicle cab to a chassis, including at least two hydraulic mounts, which are useful for controlling torque between the two bodies. The relative torque-induced displacements of the two bodies are controlled within specific limits in reaction to a pressure applied by a pressure source in response to the actuation of a valve. The valve acts in response to a sensor and the system can include a leveling valve arrangement, or a more sophisticated external electronic control, or respond to a programmed routine. The improved torque-control system behaves as though it is statically stiff for restraining torque and dynamically soft for both translational and rotational isolation purposes. In addition, the system can control torque and damping independent of the direction of application of the torque.

Abstract: A damping device which provides superior damping stiffness K", has linear damping characteristics as a function of amplitude and for which the temperature sensitivities of stiffnesses K*, K", K' have been minimized. The device includes a first second fluid-filled chambers which are interconnected by a passageway. The length and diameter of the passageway, as well as the fluid viscosity, are chosen to give the optimum damping characteristics. Further, a plurality of spring loaded pressure relief valves are integrated into the assembly to allow more flow area to open when a threshold pressure is encountered, thereby reducing the internal pressures and dynamic stiffness K* at cold temperatures.

Abstract: A mounting (20) which provides low vertical and lateral spring rates for excellent lateral and vertical vibration isolation yet provides a high roll stiffness for reacting torsional moments, while reducing isolator complexity and eliminating the need for a yoke or hanger. The mounting (20) includes a top member (34), a first arm (26) and a second arm (28) which are flexibly interleaved or attached. The first arm (26) is attached to a top member (34) by way of a pivot which can be a spring (30), the second arm (28) is also attached to the top member (34) by another pivot which can be a spring (32), and a third spring (36) attaches the arms (26) and (28) to each other. The arms (26) and (28) also attach to the supported member (22) preferably at their respective outboard ends (38), or at least one intermediate link can be used.

Abstract: A device for making electrical connection to a reciprocating element, such as to a voice coil of an actuator. An electrical flow path utilizing the helical centering springs as a primary element in conducting current ensures reliable current flow to a reciprocating element and avoids high-speed flexing of brittle wires. Hard-wired connections are utilized only between stationary elements. A second double-coil actuator embodiment employs a coaxial, substantially co-extensive pair of springs as the input and return current flow paths for each actuator.

Abstract: This invention relates to sealless designs of magnetorheological fluid dampers. With these sealless designs a piston rod extends above and below a piston head within a cylindrical housing and has frustoconical elastomer elements attached to and between the rod and housing to allow translation of the piston head and rod. The piston head has a coil contained radially therein that produces magnetic flux in and around the piston. The advantages of utilizing an MR fluid according to the invention include magnetic fields which are easily produced by low voltage electromagnetic coils, damping effects which are velocity independent, and higher yield strength obtained by the MR fluid capable of generating greater damping forces.

Abstract: Magnetorheological (MR) fluid dampers are optimized. Dimensional relationships involved in the flow of magnetic flux are related to an operational parametric ratio of magnetic flux density in the fluid to the flux density in the steel. A magnetic valve is utilized to change the flow parameters of the MR fluid and, hence, the operational characteristics of the damper. Several embodiments depicting improved piston designs, including spool as well as toroidal configurations, are disclosed. In addition, both single and twin-tube housing designs are presented.

Abstract: A method and apparatus for reducing suspension end-stop collisions is disclosed. The method and apparatus controls the operation of an isolation system having an adjustable damper assembly interconnecting relatively movable members to attenuate the transmission of forces therebetween, in which relative movement of the members is restricted beyond a certain limit by one or more end stops. Sensors monitor the conditions of the system such as the displacement, velocity and acceleration of the members. Damper command signals are provided to the damper assembly to adjust the damping characteristics of the assembly, as determined by the data, in accordance with both a primary control policy and an override control policy. The override control policy alters the damper command signals as necessary to increase the damping characteristics of the damper assembly at times when the isolation system is likely to meet or exceed the end stops in order to minimize the incidence of end-stop collisions.

Abstract: A method and apparatus for controlling suspension deflection in a semiactive damping system is disclosed. A semiactive control policy operates to set the damper force to a low magnitude when the relative position of the suspension members is within a "null band," and to a high magnitude when the relative position is within an "overshoot" band. The null band is a predefined range of displacement about the equilibrium position of the members and the overshoot band is a range about the end stops. When in the overshoot band, the high damper force limits the incidence of suspension end stop collisions that cause damaging shock inputs to the system. The high damper force is maintained once the overshoot band is entered until the relative position of the members again reaches the equilibrium position. One or more intermediate or "active" bands are defined to exist between the null and overshoot bands. When in the active band(s), the damper force is set to an intermediate magnitude to thus stiffen the suspension.

Abstract: Several improved embodiments of surface effect dampers that produce a damping force including both hysteretic and frictional components. Various improvements include an amplitude sensitive feature or decoupler mechanism to eliminate or greatly reduce the damping for low amplitude input conditions as compared to high amplitude inputs, provisions for increasing the damping force in a non-linear manner, and features for providing significantly greater damping in one direction than the other. Other embodiments include an improved rotational surface effect damper useful for damping rotational motion, and a multiaxial damper which can be used, for example, as a motor mount which has the capability for the piston to tilt relative to the axis of its piston rod, allowing accommodation of torsional rotation of the engine while not compromising vibration isolation.

Abstract: A special trackwork fastener (10) for supporting a railroad rail and attaching it to a support structure. The trackwork fastener (10) is modularly constructed and includes a top plate (20), resilient end portions (12) and (16), optional resilient center portion (14), and securing elements (18). The special trackwork fastener (10) has the versatility to be used in a large number of special trackwork situations such as turnouts, crossovers, crossings and switches or the like, which require a variety of lengths of trackwork fastener (10). The vertical compression stiffness and adjustability in length is provided by two opposed end portions (12),(16) and an optional center portion (14) which is molded or cut to length such that the portions collectively match the length of the top plate (20) and therefore the top plate (20) is fully supported along its length. The elastomer portions can be cored out to provide the desired compression stiffness.

Abstract: An improved service-life, low-profile, elastomeric mounting for placement between the side-frame-pedestal-jaw roof and the axle-box or axle-bearing adapter crown on a three-piece, railroad-car truck. The mounting minimizes the damaging compression induced edge strains resulting from the cocking motions imposed on the elastomeric mounting during railroad car braking and rocking. The addition of shims, specialized elastomer contouring, graded thicknesses of the elastomeric layers in combination with high shape factor of the elastomeric layers allows the compression induced edge strains to be significantly reduced and results in extended service-life of the elastomeric mounting.