Abstract: An anti-lock braking system includes a moveable member to be braked and a friction brake for applying a braking force. A controller actuates the friction brake in accordance with braking force demands. Braking force demands are determined by the controller by electrical input signals received from a signal generator that is mechanically linked to the brake pedal, as well as by signals from a slip sensor. The slip sensor records values from wheel speed sensor and computes values that may indicate a slippage condition. Based on the recorded and computed values, the slip sensor and sends electric signals to the controller. The friction brake includes a prestressed piezoelectric element that is lightweight, less cumbersome, and highly controllable as compared with prior anti-lock braking devices, and is actuated via electrical signals rather than a mechanical system.

Abstract: A thickness mode piezoelectric transformer is provided that has masses attached to opposing faces of the transformer. The end-masses increase the thickness of the transformer and decrease its resonant frequency. The end-masses increase the magnitude of resonant vibrations in the output layer(s) as well as the mechanical Q of the device to provide a low profile piezoelectric transformer with high power density. The preferably metal end-masses also act as high voltage output electrodes as well as heat sinks.

Abstract: A method for manufacturing a cofired multi-layer piezoelectric transformer device includes forming first and second green shapes of a sinterable ceramic composition and applying metallization layer therebetween. Upon cofiring, the composite structure comprises first and second electroactive members bonded together by a conductive layer therebetween. External electrodes are applied and the electroactive members are polarized in a thickness direction, between their two major faces. The first and second electroactive members are arranged such that deformation of one electroactive member results in corresponding deformation of the other electroactive member. The device provides substantial transformation ratios in which relatively high power may be transferred in relation to the size of the unit, operability over wide input and output frequency bandwidths, and electrical isolation of the input voltage and current from the output voltage and current.

Abstract: A composite structure is provided which resists corrosion and cracking due to water seepage and roadway use. The composite structure of reinforced concrete is wear resistant through bonding it to a liquid-impermeable overlay such as latex concrete with an adhesive imide. The imide has great adhesion to the concrete and has a thermal expansion and flexural strength comparable to the reinforced steel which prevents delamination of the imide and the overlay as road, bridge or deck roof is subjected to traffic and the elements.

Abstract: A small, lightweight, efficient, quiet electric shaver is provided in which one or more piezoelectric drivers are mechanically coupled to a cutting blade. The cutting action of the blade is generated by the piezoelectric drivers which, when electrically energized, oscillate at a predetermined frequency. The piezoelectric driver is electrically energized by a regenerative drive circuit. Hair shafts, which protrude from the surface to be shaved through a perforated foil member, are sheared at their base by the oscillating action of the blade.

Abstract: A method for manufacturing a multi-layer piezoelectric transducer having enhanced mechanical output displacement capability resulting from an increase in the amount of "pre-stress" applied to the electroactive (ceramic) layer by the pre-stress layer. The pre-stress layer is heated to a temperature above the temperature of the ceramic layer and bonded at an elevated temperature to the ceramic layer, such that, as the pre-stress layer subsequently cools down to ambient temperature, it applies a compressive stress to the ceramic layer. During the step of cooling the layers to ambient temperature, the temperature drop of the pre-stress layer is greater than the temperature drop of the ceramic layer, thereby increasing the amount of "pre-stress" applied to the electroactive (ceramic) layer by the pre-stress layer.

Abstract: A liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducer housing member, and into the exterior work medium. Acoustic waves are generated by electrically-actuated liquid-immersed piezoelectric elements housed within the device. The efficiency with which acoustic waves are transmitted from the interior of the device to the adjacent work medium is enhanced by providing an intermediate transducer housing member, disposed between the liquid in which the piezoelectric elements are immersed and the work medium, having acoustic impedances at its two major surfaces matching the respective acoustic impedances of the respective interfacing media and a continuous acoustic impedance gradient between those two surfaces.

Abstract: A laminated multi-layer piezoelectric transformer comprising two elements joined together with a conductive adhesive and having a bead of the conductive adhesive at the point of junction of the two elements on the exterior surface of the laminated multi-layer piezoelectric transformer and a mounting device for use therewith and comprising a conductive base having a first contact, and curvaceous arms extending at generally at right angles from the conductive base about said laminated multi-layer piezoelectric transformer, a portion of said arms contacting said bead and preferably designed to engage the distal ends of the arms of an insulating cap mounted on the opposing side of the laminated multi-layer piezoelectric transformer said cap having a second contact therein. This combination configured for mounting on a circuit board is also described.

Abstract: A piezoelectric motor has a piezoelectric transducer disposed within a motor housing. The piezoelectric transducer is constructed of one or more piezoelectric elements, the opposite ends of which are loosely secured within recesses in the interior walls of the motor housing. Electric contact plates disposed on opposite major surfaces of each piezoelectric element hold the center portions of the piezoelectric elements in fixed relationship to each other and provide a means of conducting electical energy to the respective faces of the piezoelectric elements. A moveable piston member is attached to one of the contact plates. When an alternating voltage potential is applied across the major surfaces of the piezoelectric elements, the center portions of each of the piezoelectric elements, as well as the piston attached thereto, reciprocates within the motor housing while the ends of each of the piezoelectric elements remain secured within the recesses in the interior walls of the housing.

Abstract: A contact device for securely and reliably attaching electrical leads to a laminated multi-layer piezoelectric transformer and comprising a pair of conductive lead attachment plates, disposed on opposite sides of the laminated multi-layer piezoelectric transformer, each having first and second surfaces, the first surface having at least one leg extending therefrom to contact the laminated multi-layer piezoelectric transformer at a node and the second surface being sufficient to permit secure and durable attachment of electrical leads thereto. A variety of geometric configurations of the contact device of the present invention suitable or adaptable to a variety of laminated multi-layer piezoelectric transformer geometries are also described. Such a device, useful for the attachment of a laminated multi-layer piezoelectric transformer to a circuit board, is also described.

Abstract: Fluorescent lamp excitation circuits are provided which use a resonating piezoelectric transformer along with complementary circuit components, to efficiently convert a DC first voltage to a transformer-output AC second voltage. In the preferred embodiment of the invention, A High Displacement Piezoelectric (HDP) transformer achieves sufficiently high voltage output to "cold fire" a gas discharge lamp. The disclosed circuit may be modified using conventional electrical sub-circuitry to pre-heat the cathodes of the lamp.

Abstract: An adhesive viscous liquid screed for dispensing a uniform thickness of an initially viscous liquid material onto a planar work surface in order to produce a film of predetermined thickness, length and width. The screed engages a planar horizontal application surface and a reservoir is filled with a liquid adhesive. As the screed is propelled forward along the application surface, the pressure on the adhesive due to gravity causes it to be forced out of the reservoir and through a first release orifice, thereby depositing a thin film of liquid adhesive. The height of the film is determined by the distance between the application surface and the bottom surface of a rib defining the release orifice and the width of the film is determined by the distance between the substantially vertical sides of the first release orifice.

Abstract: Circuits for use in ignition systems are disclosed which use a resonating piezoelectric transformer along with complementary circuit components, to efficiently convert a DC first voltage to a transformer-output AC second voltage. In the preferred embodiment of the invention, a High Displacement Piezoelectric (HDP) transformer converts a DC voltage into an AC voltage which is rectified into a DC signal of sufficiently high voltage to create a spark across the spark gap of a spark plug. The transformer circuit may be a "self resonating" circuit which relies on an initial pulse from turning on the DC power supply to cause the transformer to begin resonating. In a modified circuit the circuit is not "self resonating" and instead has a phase shift oscillator sub-circuit that provides small pulse signals to start the transformer resonating when the circuit is initially turned on.

Abstract: A method is disclosed for advantageously modifying the texture or character of a plastic work material by applying acoustic energy at the work material's natural resonant frequency via a transducer assembly including vibrating the transducer assembly in air to determine the natural resonant frequency of the transducer assembly; determining the natural resonant frequency of the work material and the transducer assembly together; subtracting the natural resonant frequency of the transducer assembly from the natural resonant frequency of the work material and the transducer assembly together to determine the natural frequency of the work material; and applying acoustic energy to the work material at the determined natural frequency of the work material. The transducer assembly includes piezoelectric actuators which provide the acoustic energy.

Abstract: A liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducer housing member, and into the exterior work medium. Acoustic waves are generated by electrically-actuated liquid-immersed piezoelectric elements housed within the device. The efficiency with which acoustic waves are transmitted from the interior of the device to the adjacent work medium is enhanced by providing an intermediate transducer housing member, disposed between the liquid in which the piezoelectric elements are immersed and the work medium, having acoustic impedances at its two major surfaces matching the respective acoustic impedances of the respective interfacing media and a continuous acoustic impedance gradient between those two surfaces.

Abstract: A peristaltic piezoelectrically actuated fluid pump including two or more pairs of piezoelectric deformable members that are self-actuated, a flexible hose member, a pump chamber, inlet and outlet ports for communicating the pump chamber with the exterior of the flexible hose member, valves for opening and closing the ports, and a power supply is provided. The diaphragm members may include a prestressed piezoelectric element which is durable, inexpensive and lightweight as compared with diaphragm members of prior diaphragm pumps of comparable discharge capacity, and is actuated via electrical signals from an outside power source. Each pair of piezoelectric diaphragm members is actuated out of phase with the other(s) so as to allow fluid to be pumped through the flexible hose member peristaltically.

Abstract: A piezoelectrically actuated fluid pump including a pump housing, a pump chamber, inlet and outlet ports for communicating the pump chamber with the exterior of the pump housing, valves for opening and closing the ports, a pre-stressed piezoelectric diaphragm member which is self-actuated, a piston member, and a power source is provided. The diaphragm member includes a prestressed piezoelectric element which is durable, inexpensive and lightweight as compared with diaphragm members of prior diaphragm pumps of comparable discharge capacity, and is actuated via electrical signals from an outside power source. The diaphragm member drives the piston member. No exterior mechanisms are necessary for driving the diaphragm member.

Abstract: A circuit including a transformer, preferably a laminated piezoelectric transducer, in combination with a positive feedback amplifier circuit, capable of serving: 1) to produce either an audible or ultrasonic signal; or 2) as an energy source capable of driving an auxiliary high voltage device with an initial and continuing low voltage source such as a battery.

Abstract: A method and apparatus for manufacturing prestressed piezoelectric actuators which maximizes output, and increases the precision and efficiency with which the multi-layer actuators are made. Individual layers of the piezoelectric actuators are automatically stacked and registered with respect to each other within press members prior to bonding the layers to each other with a thermoplastic adhesive. Compressive force is applied while heat is conductively transferred from a heating element to the actuator in order to raise the temperature of each of the layers above the melting point of the thermoplastic. The temperature of the heating element is then decreased until the temperature of the actuator layers drops to below the melting point of the thermoplastic adhesive, thereby bonding the layers. Compressive force is then released, and the actuators are removed, further cooled and polarized.

Abstract: A vibrating hand trowel for finishing plastic concrete. The vibratory mechanism includes piezoelectric elements which vibrate at a high frequency when a voltage is applied to them. The trowel as a whole includes a top piece including a cover plate and handle, and a bottom piece including the piezoelectric elements mounted on a rib and a flat bottom which contacts the concrete. The top and bottom piece are preferably attached by a series of screws. The vibrating trowel is pulled over the concrete creating a smooth, wet layer useful for lubrication of the area where the trowel and concrete are in contact. This layer develops because the vibrations cause water and air to rise to the top of the concrete. The invention will allow for easy finishing of plastic concrete because of its lightweight and simple design. The invention will also create a smooth finish of the hardened concrete.