Abstract: An ultrasonic probe for measuring liquids at high temperature and under high pressure. The ultrasonic probe comprises a leak-tight protective sleeve which has an end face closed by a thin metallic wall. The protective sleeve contained internal elements which are in particular a transducing piezoelectric plate and a damping cylinder. The piezoelectric element has one face which is in mechanical and electrical contact with the internal face of the thin sleeve wall and the other face which is supported on a damping cylinder. The thin sleeve wall of the sleeve end face is constituted by a metallic layer obtained by cathodic sputtering.

Abstract: An intrusion sensor uses thin film piezoelectric transducers to sense nea mechanical vibrations. A hose-like sheath contains a pair of insulating strips which carry conductive leaves on their outer surfaces. A series of longitudinally arranged segments of a thin film piezoelectric material are coupled to the leaves to provide signals representative of impinging mechanical vibrations. Since adjacent ones of the thin film segments are alternately polarized, signals are created only when the vibrations are nearby. Greater sensitivity to nearby vibrations is assured when each of the segments is fabricated from several layers of the thin film piezoelectric material.

Abstract: The construction and method of operating a signal generator which provides an electrical output in response to an input mechanism such as a loading by finger are disclosed. The generator has the appearance of a plate and includes a sandwich structure comprising a conductive substrate, a coating of piezoelectric material and usually a plurality of discrete electrodes joined to the exposed surface thereof. The coating is deposited on the substrate as a slurry and is chemically bonded to the substrate. In order to produce an electrical output signal, prescribed locations on the plate are subjected to a force such as can be applied by the touch of a finger and a voltage is generated across the piezoelectric coating between the point of contact on the substrate and the adjacent electrode. The output signal is used either directly or after being amplified to drive various functionally responsive devices.

Abstract: A cable supporting along its length one or more detector units, each comprising a bendable board which is much longer than it is wide and which supports near its center a piezoceramic transducer whose output is responsive to bending of the board, the cable being bared in the vicinity of each transducer and having its conductors connected with the two terminals of the piezoceramic transducer, the board and the portions of the cable immediately adjacent to the board being unitized by a heat shrunk tube which tightly conforms to the board and said cable portions and unifies them so that they become part of the cable with commensurate stiffness.

Abstract: A fluid pessure transducer comprises a plate-like crystal. The pressure gives rise to a force which is applied by two seatings situated by opposing edges of a crystal in a direction generally along the face of the crystal. The change in oscillating frequencies of a part of the crystal provides a measure of the force and hence the fluid pressure.In the past a second matched crystal has been employed to provide compensation for inaccuracy brought about by undesired frequency deviation due to ambient temperature change of the instrument. The present invention consists of a single crystal having on it two oscillating areas simulating the behaviour of the original pair of crystals. The single crystal facilitates manufacture of the device and improves the accuracy of the instrument.

Abstract: A piezoelectric resonator, particularly for pressure, acceleration, temperature and load transducers, consisting of a resonator core having holding discs on its opposite sides, said holding discs being formed of solid body layers, said layers consisting alternatively of materials having strongly different acoustic impedance for unit cross-sectional area.

Abstract: A self powered tire condition indicator system is disclosed. The system comprises a plurality of wheel mounted transmitting assemblies which communicate by a radio frequency transmission to a receiver located within the operator compartment of a vehicle. Each of the transmitting assemblies generates its own transmitting power by converting the mechanical compression of a flat tire into electrical energy. The electrical energy is used to generate an intermittent characteristic tone associated with a deflated tire condition by the frequency modulation of a carrier.

Abstract: A pressure sensing device comprising a ring surrounding or adapted to surround a body subjected to internal pressure; means to connect the ring physically to the body at spaced locations, the connecting means transmitting to the ring dilation and contraction movements of the body due to variation of pressure therein; said movement transmitted by the connecting means causing a portion of the ring between adjacent spaced locations to flex elastically in the manner of a bending beam, and an electrical transducer mounted upon said flexing portion of the ring, to produce electrical signals dependent on the pressure variation. One form of the device is adapted to clamp around an engine fuel line to sense fuel pressure. Another form of the device is adapted to measure engine cylinder pressure. In a further development of the invention these two forms of device are combined to feed information to engine analysing circuitry producing a visual display.

Abstract: The invention is a single crystal force transducer in which the crystal is simultaneously resonated in two different modes having substantially the same frequency-temperature characteristics and different frequency-force characteristics. The difference in the change between the two resonant frequencies with a force applied to the crystal is therefore a temperature compensated signal indicative of the applied force. In the preferred embodiment the two resonant modes are anharmonic modes having a plurality of antinodes angularly disposed to each other.

Abstract: A piezo-electric disc (e.g., a force transducer or a radio reference crystal) is mounted on its edge between two opposing anvils of material which is selected to plastically deform only under a relatively high proof load applied to the disc through the anvils while an extreme pressure lubricant is present between the edge of the disc and the anvils to provide seats of limited area for the edge of the disc.

Abstract: A device for detecting deformations in mine roofs wherein an open cylindrical casing having inner and outer threaded surfaces is threaded into the mine roof. A piezoelectric crystal is mounted within the casing to sense the deformations and stresses in the mine roof. Provision is made for mounting a plurality of piezoelectric crystals within the casing whereby stresses at varying locations are sensible.

Abstract: A transducer capable of measuring force or fluid pressure comprises one or more plate-like crystals; electrical means for exciting each crystal into resonance; a base upon which sits a first seating which supports the lower edge of said one crystal; a second seating disposed at the upper edge of the crystal so as to secure the crystal in a position perpendicular to said base; each seating comprising cylindrical or semi-cylindrical surfaces the cylindrical faces of which, are arranged to bear on the crystal edge so as to produce, in response to said force, a change of the resonant frequency of that crystal with respect to the other crystal or crystals.

Abstract: To provide a piezoelectric pressure pickup for a fuel injection line, a piezoelectric ceramic plate is mounted between two pressure plates within a pipe clamp which is clamped around the fuel line and has a low coefficient of expansion compared to that of the injection line. One side of the piezoceramic plate is acted upon through one of its pressure plates by a force transmission element and is braced on the other side with a leaf spring which is compressed by means of a pressure screw.