Abstract: A method of finishing concrete using a vibrating tool to consolidate a “dry shake” aggregate into the upper layer of the concrete. The use of the vibrating tool causes moisture within the concrete mass to migrate into the surface layer where the moisture may hydrate the aggregates in the dry shake mixture. The ability to cause upward migration of water in the concrete mass provides a larger window of finishability for the concrete. The vibrations also provide thorough consolidation of aggregates in the upper layer of the concrete mass helping to prevent delamination.

Abstract: A self-powered switching device using a prestressed flextensional electroactive member generates a signal for activation of a latching relay. The electroactive member has a piezoelectric element with a convex and a concave face that may be compressed to generate an electrical pulse. The flextensional electroactive member and associated signal generation circuitry can be hardwired directly to the latching relay or may be coupled to a transmitter for sending an RF signal to a receiver which actuates the latching relay.

Abstract: A piezoelectrically actuated vibratory motor comprises actuators that are mounted “vertically” with their edges attached to top and bottom mounting members. An oscillating voltage applied to the actuators causes them to contract and expand to move the attached mounting members in a direction essentially parallel to the faces of the actuators. The force transmitted to the mounting members at the edges of actuators is greater than the typical force taken at the center of a face of the actuator.

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 method for manufacturing high deformation piezoelectric actuators and sensors using a continuous tape manufacturing process is provided. The ceramic layer is dispensed between two metal/adhesive layers to form a composite tape and is tack welded together. Lengths of composite tape are heated and then cut into individual actuators. A special pattern punched in the tapes allows for ease of alignment of the layers of the actuators.

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 multi-segmented flextensional transducer includes a plurality of electroplated electroactive members which deform in concert when energized by an electrical field. Each electroactive member has a convex surface at both ends. A connection member with opposing concave surfaces is disposed between adjacent electroactive members. The electroactive members are arranged such that the convex faces of each intermediate electroactive member engage a concave face of an adjacent connection member, thus forming a cooperative array or "train" of electroactive members and connection members. The opposite ends of the train of electroactive members and connection members is received by a frame which holds the end electroactive members in fixed relative position. The electroactive members are high deformation flextensional piezoelectric elements.

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 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 mechanism comprised of piezoelectric elements which vibrate at a high frequency when a voltage is applied to them. The piezoelectric elements are mounted on a rib so that their free ends extend from the rib. When the piezoelectric elements are energized the free ends vibrate with a "wing-flapping" motion. Weights may be attached to the free ends of the piezoelectric element to increase the inertial component of vibration. In the preferred embodiment of the invention, the piezoelectric elements are prestressed. The invention will be an inexpensive substitute for other vibratory devices.

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.

Abstract: Vibrational energy is introduced into a portion of a liquid-solid work mixture at a natural resonant frequency of that portion of the mixture while that portion of the mixture is in a fluid or semi-fluid state. A vibrating apparatus imparts controlled vibrations either onto the surface or beneath the surface of the liquid-solid work mixture in sequential stages, the frequency of vibrations generally increasing with each subsequent stage, corresponding to an increase in the natural resonant frequency of the progressively-narrowing liquid portion at the top of the liquid-solid work mixture. A resonant frequency-indicative condition of the liquid portion of the work mixture adjacent the vibrator apparatus is sensed as the vibrator apparatus moves across the top surface of the liquid-solid mixture, and the output frequency of the vibrating apparatus is correspondingly adjusted in accordance with the sensed condition as the vibrator apparatus travels.

Abstract: Vibrational energy introduced into plastic concrete structures, such as concrete slabs, decks and similar or related concrete structures, at or near the natural resonant frequency of the liquid concrete mass, expedites the consolidation and setting of the concrete. A vibrating apparatus imparts controlled vibrations either onto the surface or beneath the surface of the concrete mass in sequential stages, the frequency of vibrations generally increasing with each subsequent stage, corresponding to the increase in the natural resonant frequency of the progressively-narrowing liquid concrete at the top of the structure. The relatively more consolidated and more dry concrete (typically near the bottom of the slab) is substantially unaffected by the non-resonant frequencies vibrations. In one modification, sensors determine the resonant frequency of the liquid concrete mass during each pass of the vibrator apparatus, and the frequency of the vibrating member is automatically adjusted, accordingly.

Abstract: Vibrational energy introduced into plastic concrete structures, such as concrete slabs, decks and similar or related concrete structures, at or near the natural resonant frequency of the liquid concrete mass, expedites the consolidation and setting of the concrete. A vibrating apparatus imparts controlled vibrations either onto the surface or beneath the surface of the concrete mass in sequential stages, the frequency of vibrations generally increasing with each subsequent stage, corresponding to the increase in the natural resonant frequency of the progressively-narrowing liquid concrete at the top of the structure. The relatively more consolidated and more dry concrete (typically near the bottom of the slab) is substantially unaffected by the non-resonant frequencies vibrations. In one modification, sensors determine the resonant frequency of the liquid concrete mass during each pass of the vibrator apparatus, and the frequency of the vibrating member is automatically adjusted, accordingly.

Abstract: A joint between adjacent concrete slabs for overcoming existing problems which occur due to large scale relative movement of adjacent concrete slabs which results from the slabs shrinking when aging. More specifically, a resilient finger joint for concrete slabs is provided which allows and adjusts for relative vertical movements of adjoining slabs with the joint including an arrangement for absorbing vibrations and impact loads encountered which result from traffic passing over the joint between adjacent slabs. The joint includes a plurality of fingers supported by a resilient bed. The fingers are positioned in staggered, interdigitated relation and each finger is associated with an anchor alongside of and partially overlapping one end of the adjacent finger with a pivot pin or shaft interconnecting the anchors and fingers with each finger including an end that is free of an opposing anchor but supported by the resilient bed.

Abstract: A paddle shaft assembly for a mixing apparatus including a quickly and easily removable quill shaft provided with a unique seal structure associated with the shaft and a unique mounting and handle structure to enable disassembly of the shaft in relation to a mixer drum and paddle assembly in the drum. The removable shaft is provided with a flanged end plate having keyhole slot connections to a flange on the end of a rotatable sleeve sealed in relation to the drum for removably supporting the shaft and a loop type handle attached to the end plate to facilitate manipulation of the end plate and shaft to remove and replace the shaft. A seal assembly is associated with the shaft, rotatable sleeve, end plate and flange to seal those areas of the shaft and sleeve to preclude passage of the material being mixed into the area between the shaft and rotatable sleeve, and between the flange and end plate.

Abstract: A concrete joint in concrete slab structures in which the joint includes an insert that is retained in centered position in a slot or recess formed in the upper surface of a concrete slab generally in alignment with a crack or fracture line extending downwardly from the slot or recess formed in the concrete slab. The bottom of the slot or recess is provided with a seal of cementitious material which extends completely across the bottom of the slot or recess and fills the crack or fracture line with the lower edge of the insert being inserted partially into the cementitious seal which is in the form of a quick setting sand and cement mixture which has high compression strength and low tensile strength and which will adhere to concrete surfaces but will not adhere to the insert. The space above the bottom seal on each side of the insert is then filled with a filler of an epoxy or similar material which encapsulates the spring clips and fills the slot or recess on both sides of the insert.

Abstract: A sensor mounted on a frame measures inclination of a sensitivity axis above two contact points on a surface on which the frame is positioned. The signal output of the sensor is converted to digital elevation readings of opposite polarity displayed through windows on opposite sides of a handle through which the frame is rotated about alternate contact points into measurement positions along a measurement line marked on the surface.

Abstract: The difference in elevation between two closely spaced points on a surface is sensed by an instrument that is sequentially positioned at equally spaced locations along a measurement line to provide data from which a surface profile may be plotted. The instrument frame mounts a sensor having a sensitivity axis parallel to a contact line connecting pivot contact points at which the instrument engages the surface to provide a readout adjusted and calibrated to be in terms of vertical distance between the two contact points.

Abstract: A pair of elongated, rigid electrical rods held by a frame in fixed parallel spaced relation to each other are connected to an ohmmeter circuit to measure linear resistance along one of the rods from a taut datum wire in contact with the rods. The other of the rods has a non-conductive pivot element at one end positioned in contact with a test surface at a point intersected by an axis parallel to said rods about which the frame is angularly displaced to bring the rods into gripping contact with the datum wire.