Abstract: A relatively solid mounting surface, which may be part of a leveling gimb supports a piezoelectric bearing mount which has the properties of an acoustic transducer. The transducer has electrodes thereon which are powered from multi-phase electrical sources causing the bearing mount, and a bearing jewel which is rigid therewith, to move so as to dither the jewel in a rotary or other preselected fashion, thereby reducing bearing friction. Bandwidth, level and phasing sequence of the power sources are adjustable permitting optimized average dynamic motion and corresponding increased readout accuracy.

Abstract: A piezoelectric element for incorporation in pressure, force or acceleration transducers, in which at least two piezoelectric flat plates loaded in shear mode are arranged on both sides of a central support and are retained under compressive pre-tension by pressure distribution members bearing externally on the piezoelectric plates; a compression form member provided with a location hole for the support, the piezoelectric plates and the pressure distribution members is fitted over the pressure distribution members by direct or indirect shrinking the pressure distribution members are preferably made of two exact fitting cylindrical segments transmitting the tension forces evenly over the piezoelectric plates.

Abstract: Axes X', Y' and Z' of a resonator are established from the axes X, Y and Z of a quartz crystal by virtue of two rotational movements through angles .phi. and .theta., respectively. The resonator is energized to vibrate in accordance with the fundamental torsional mode. The angles of cut .phi. and .theta. are such that the first-order temperature coefficient is zero. The torsional mode may be coupled to a flexural mode in order to render the second-order temperature coefficient zero. The fork tines extend in the X' direction. In other embodiments the tines extend in the Y' direction and the rotation .phi. and .theta. are about the X and Z' axes, respectively.

Abstract: A gyroscopic device comprising a beam, column or other continuous unitary structure of consistent vibratory characteristics along its full length and including piezoelectric material. The piezoelectric effect is used both excite the structure into resonant vibrations along a first axis and then, when a rate of turn is applied along a second axis at right angles to the first, to detect that rate of turn by sensing vibrations set up in the beam in a direction parallel to a third, orthogonal axis due to Coriolis forces resulting from the applied rate of turn. The beam may be held at both ends, or may be supported at one end only with the other end free. The vibrations applied to and sensed within the beam by means of the piezoelectric effect may be parallel, transverse and radial relative to the beam axis, or may be in a rotary sense around that axis. A mode of vibration in which opposite faces of the beam oscillate in parallel directions but out-of-phase is also disclosed.

Abstract: A rotary actuator for converting electrical energy into rotating torque comprises a stator, a rotor, a pair of annular first piezoelectric elements contracting and expanding in the radial direction in response to the application of an electrical signal, and a plurality of second piezoelectric elements disposed between the first piezoelectric elements and a holding portion of the stator for causing displacement of the first piezoelectric elements in the circumferential direction in response to the application of the electrical signal. These piezoelectric elements are alternately energized to continuously rotate the rotor.

Abstract: A piezoelectric rotary actuator including: a rotatable member; a spiral member fixed at its inner end to the rotatable member; one or more piezoelectric layers attached on one or both sides of the spiral member; means for rotatably supporting the rotatable member relative to the outer portion of the spiral member; and an electrode for applying a voltage across the piezoelectric layer or layers, to bend the spiral and rotate the rotatable member.

Abstract: A windmill (10) has a member (12) which is torsionally displaceable and coupled to a transducer (62) to produce usable energy.

Abstract: A tuning fork-shaped quartz oscillator comprises a U-shaped quartz oscillator body which comprises of a pair of vibration arms having a rectangular cross section and a base connecting the vibration arms at one end. Four excitation electrodes are provided respectively on the four sides of each vibration arm, each electrode having a portion laid on two adjacent sides. The oscillator further comprises connecting means including a first input terminal and a second input terminal which supply drive voltage to the excitation electrodes so that the vibration arms keep vibrating in opposite phase relation in both a bending mode and a twisting mode.

Abstract: The invention relates to an acceleration pick-up which can be produced at favorable cost in large numbers, for which new constructional means are used. The apparatus consists of a mushroom-shaped support screw (6,56), which is inserted directly in the synthetic material housing (8) of the measuring device and which mounts and retains both the mass sensor arrangement (1, 2, 3, 4), the printed circuit board (15) as well as the housing cover (9). In the immediate vicinity of the mushroom-shaped head (7) at least one flat holding magnet (30) is likewise inserted directly in the synthetic material housing (8). In order to screen the sensor arrangement against disturbance effects, the inside of the synthetic material housing is coated with a conducting metal layer (26,28,66) for inner screening, which is connected to the screening of the connecting cable piezoelectric, piezoresistive, inductive or other systems can be used as sensor elements.

Abstract: A piezoelectric strain/force transducer is described, which is attached preferably by only one locking screw to a test specimen or machine part. The force transmitting member of the transducer comprises two bearing surfaces at a distance apart, which bear frictionally on the surface of the machine part and experience a change in spacing in the case of a change in length of the machine part. Due to this, a resilient member, which can be adapted to a desired sensitivity of the gauge, is tensioned and a set of piezoelectric plates held under precompression in the force-transmitting member are subjected to a corresponding shearing force. The piezoelectric plates are cut or polarized so that they respond piezoelectrically solely to shearing forces. The resulting piezoelectric charge is a measurement of the strain or mechanical stress of the machine part and can be used for monitoring or controlling machines or components, in particular those which are subjected to cyclic loads.

Abstract: An accelerometer having a base unit carrying one or more transducers and encapsulated in a housing. The base includes a base piece and a prism-shaped stud with a rectangular cross-section having shear sensitive transducing elements, with associated seismic masses, fixed on the opposite, wide faces of the stud. The stud is shaped like an inverted T, so that the cross-section of the lower T-bar part has the same thickness but a greater lateral dimension than the T-leg part which carries the transducing elements. The stud is affixed perpendicular to the base piece with high precision using the lower T-bar part of the stud as a guide, and is easily fastened to the base piece without the use of screws or cement.

Abstract: The vibration motor of the invention comprises a concentrator of torsional vibrations including at least two stages. The first one of the stages takes up vibrations from a piezoelectric cell while the second stage contacts a rotor. The concentrator is provided with means for transforming piezoelectric cell vibrations into torsional ones, said means being fashioned as rods provided on the side surface of the first stage. The rods are located in a plane normal to the concentrator axis and inclined each at an acute angle to a tangent at the point where the rod is attached to the line of intersection of the side surface of the first stage with said plane. The rods serve as resonators of longitudinal vibrations propagating therein.

Abstract: A method for the manufacture of a force transducer consisting of a base carrying a stud which carries a set of shear sensitive elements, each having a seismic or force transmitting mass attached to it, the masses being fixed to shear sensitive elements fixed to the stud by means of a cylindrical spring clip surrounding the force transmitting masses and supplying elastic force through the elements to be fixed to the stud, the method involving cutting of slots which are parallel to the axis of the rod with a depth greater than the height of the shear sensitive elements, insertion of shear sensitive elements into the slots, pressing of a cylindrical spring clip around the slotted part of the rod, and cutting radially into the rod so as to remove the material making up the bottom of said slots.

Abstract: A method and apparatus for transmission of ultrasound to and reception of ultrasound from a fluid from outside its container. An ultrasonic transducer generates sound waves longitudinally in a transmission bar that has a reflecting surface at such an angle with the ultrasonic path that the longitudinal waves are internally reflected as shear waves in the direction of an interface between the transmission bar and the fluid. The impinging of the shear-mode waves on the interface results in an efficient transmission of energy into the fluid and an efficient reception of echo signals from the fluid. Since longitudinal waves are coupled from the transducer to the metal, a rigid bond between transducer and metal is unnecessary. The coupling may be achieved by means of a liquid-filled interface that does not subject the delicate transducer to damage from stresses produced by differential thermal expansions.

Abstract: A detector of acoustic emissions from a structure includes a piezoelectric element responsive to both compressional wave energy and to shear wave energy from any direction so that the source of the acoustic emission may be determined.

Abstract: Elastic waves are propagated in a waveguide comprising an elongate central core region and an outer cladding region, the cladding region having a larger bulk shear elastic wave velocity than the core region. Transducers at respective ends of the waveguide couple between electrical signals and "shear" mode elastic waves in which the principal particle displacement is substantially perpendicular to a plane passing through the central longitudinal axis of the core region. The cladding region is sufficiently thick to ensure that the particle displacement profile is substantially zero at its outer surface. The waveguide is mounted in a medium suitable to mechanically support it and to protect it against external mechanical shock.

Abstract: A transducer for transmitting and/or receiving acoustic energy under water includes a head mass, a tail mass, and an active motor/generator section which includes piezoelectric elements active in the shear mode of operation. Another embodiment illustrates a transducer of a bender configuration.

Abstract: A dynamic pressure sensor employing piezoelectric ceramic elements in a shear mode. The ceramic elements are bolted in a sandwich-like assembly which includes collector plates to a support member; a piezoelectric compensating assembly is also bolted to this support member. The sensor provides high sensitivity and is particularly insensitive to vibration, case strains and the like.