Abstract: In order to provide a unitary, rugged and simplified engine knock sensor assembly for internal combustion engines, which is readily tunable after manufacture to particular frequency characteristics of a given engine, the invention provides a cantilevered bending oscillator which is clamped together with a suitable electrical contact in an axial channel of a metallic cylindrical socket. The radial clamping forces are permanently provided by deformation of the socket material, for example by mortising, or other dimensional changes of the socket material. A number of embodiments is presented. The invention also includes a method for simultaneously producing two separate electrical contacts from a single contact element.

Abstract: The invention relates to devices using transducer elements comprising a film of piezoelectric polymer arranged between electrodes. The transducer element in accordance with the present invention is in the form of a thermoformed protuberance. These devices are used for detecting and generating elastic compression waves, for infrared radiation, and for storing electrical energy.

Abstract: The present invention is an inertial rate of turn sensor of the vibratory type employing force feed back techniques for maintaining the free end of a cantilever in a nulled lineal path, constant with respect to the casing of the instrument. The current required to maintain the constant lineal path is then a measure of the amplitude of the rate of turn of the case and the phase sense of that current defines the sense of rotation of the case and therefor of the craft.

Abstract: An accelerometer utilizes a pair of SC-cut crystals which respond differentially to acceleration inputs. Each crystal exhibits a highly temperature sensitive resonant mode and a relatively temperature insensitive resonant mode. Both modes are excited simultaneously by an oscillator. The difference frequency data between respective modes of each crystal, as well as the difference frequency data between the two modes of one of the crystals, is processed to obtain a temperature compensated value of acceleration.

Abstract: A piezoelectric knock sensor comprises a flexing plate at one end of a generally cylindrical case with a mounting stud extending perpendicularly therefrom and a piezoelectric element attached to the flexing plate within the case for flexure with the flexing plate. When the sensor is attached to a component of a multicylinder, internal combustion engine, the case vibrates interactively with at least a portion of the component through the flexing plate and exhibits both an interactive resonance with the component for a wide resonance peak and response to transverse as well as axial vibrations. The sensor is thus capable of resonant response to knock-induced vibrations from all the cylinders even if the characteristic knock frequencies of the individual cylinders differ over a range too great to be encompassed by a self-resonant sensor. In addition, the sensor has the comparatively high output level of a piezoelectric device and simple construction suitable for mass production.

Abstract: A knocking detector for an internal combustion engine includes a vibration unit comprising an inertial mass member and springs which are mounted in a housing attached to an engine body. The spring constants of the springs are so selected that the resonant frequency of the vibration unit becomes substantilly equal to the frequency of vibration due to knocking of the engine, and the vibration of the vibration unit is detected and converted into an electric signal.

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: An electronically tunable resonant accelerometer is shown wherein the frequency of a resonant peak may be adjusted over a range of frequencies. A piezoelectric element of the accelerometer is used with a seismic mass to generate an output voltage in response to reciprocating motion of the accelerometer. In a compression mode, a feedback loop applies a feedback voltage to a second piezoelectric element mechanically coupled to the first mentioned piezoelectric element. In a cantilever mode, a feedback loop applies a feedback voltage to another location along the first mentioned piezoelectric element which is formed from two bonded piezoelectric elements.

Abstract: A lightweight accelerometer in a casing or housing, having a very small base member to mechanically contact a surface, vibrations of which are to be determined; a piezoelectric element connected to the base, a seismic mass connected to the piezoelectric element, at least one thin circular diaphragm peripherically fixed to the housing, and with the base, the piezoelectric element, and the seismic mass fixed on, and axially symmetric to, the center of diaphragm and a soft pad member on the housing providing support on and dynamically isolating the housing from the vibrating surface. Several embodiments are disclosed and in each embodiment vibrations are directly transmitted from the vibrating body or surface to the piezoelectric element through the base, a very small half of a steel sphere.

Abstract: A short period seismometer sealed in a housing with an oil-immersed frame supporting a mass suspended for displacement along an axis of sensitivity of the instrument, one end of the mass being merely guided and constrained for axial movement, and the other end of the mass being supported by a spring disc assembly clamped in the frame at its periphery and attached to the mass at its center, the disc assembly including a piezoelectric disc bonded to a spring metal disc on the opposite face thereof from the mass and the piezoelectric disc having a diameter about 0.68 times the diameter of the spring metal disc to achieve optimum output signal, the mass restoring force being concentrated in the spring disc assembly, and the constraining guide at the other end of the mass contributing only insignificantly to the restoring force.

Abstract: A piezoelectric flexible arm member is mounted to a base at one end and supports a torque coil in a magnetic field at its other end. The torque coil comprises a seismic element disposed to be moved in accordance with acceleration forces applied thereto. A voltage is produced across the piezoelectric flexure arm when movement of the torque coil causes it to flex. The torque coil may include means to induce a signal in a position detector circuit representative of the position thereof. Both the signals from the piezoelectric member and the position detector may be used as error signals in a servo amplifier system to provide restoring forces to the torque coil and to produce an output signal representative of acceleration forces. A third conventional error signal may also be employed in the system.

Abstract: There is disclosed a transmitter for detecting and transmitting peak amplitudes of a cyclic voltage developed by a transducer responsive to vibration. The transmitter includes an input amplifier receiving the transducer output signal in circuit to a voltage peak detector which generates a voltage signal responsive to the peak of the amplified transducer signal, a voltage peak integrator which develops an analog output voltage signal responsive to a predetermined, stored number of pulses of the pulse voltage signal and output amplifier which generates an output current signal proportional to the summed pulses of the voltage signal. The transmitter operates at a steady current drain of a few milliamperes and develops an output current signal in the 4-20 milliampere range whereby it can be directly coupled to most electrical instrumentation.

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 pressure sensitive switch including a poly (vinylidene fluoride) (PVF.sub.2) sheet arranged to be compressed and laterally outwardly distended under a load carrying on each major surface thereof contact means for receiving a signal generated by the sheet when compressed and distended two thick blocks of solid elastomeric material between which is sandwiched the sheet, and means for compressing and laterally outwardly distending both blocks by relative motion toward each other thereby in the absence of tension forces compressing and laterally outwardly distending the sheet sandwiched therebetween to generate the signal.

Abstract: A piezoelectric acceleration transducer has a piezoelectric element with a plane surface arranged in contact with a mass. The mass and the piezoelectric element are held in fixed relationship to each other by a support structure arranged in such a manner that inertia forces effective on said mass are directed to be effective perpendicularly on the plane surface of the piezoelectric element. A bearing point or line is provided between the mass and the support structure in such a position that the directional sensitivity of the transducer may be determined by said position.

Abstract: A piezo electric transducer employs a stack of piezo electric crystals interposed between electrodes and maintained under compression to develop an electrical charge which instantaneously corresponds to the acceleration of the device. One or two electrical resistors in series with the piezo electric crystal stack output develops a charge which instantaneously corresponds to the velocity of the device. The velocity responsive charge is delivered to a charge converter which may be located remotely from the piezo electric transducer. The charge converter generates an electrical signal having a voltage which is proportional to the instantaneous velocity of the device. The assembly permits use of high-sensitivity piezo electric crystals.

Abstract: A piezoelectric transducer for use as an accelerometer has a polarized piezoelectric element sandwiched between a spigot and a sleeve. The element is hollow and conical, or frusto-conical so that the sandwiching effect can be achieved by means of axial clamping, as by a screw. This avoids the use of solders or adhesives and thus allows high temperature operation.

Abstract: A piezoelectric polymer transducer for converting mechanical energy into electrical energy includes a transducing means formed of a polymeric piezoelectric layer of material that is connected at its ends to a support means in such fashion that it can readily vibrate. The piezoelectric layer is coated on at least an outer portion of each of its planar surfaces with conductive electrodes and a weight is attached to the piezoelectric layer to act as an inertial mass to accentuate bending of such layer in response to movement of the support means.

Abstract: A motion detector that includes one or more sensing units fastened by at least one end to an interior portion of a housing. The sensing units are flexible so that they readily bend in response to movement of the detector, and a small weight is mounted on each sensing unit to accentuate such bending. Each sensing unit includes a thin strip of poled, polymeric piezoelectric material having planar surfaces. Conductive electrodes are carried on only the portions of such surfaces adjacent the end (ends) of the sensing unit fastened to the housing. An electronic circuit is connected across the conductive electrodes for sensing electrostatic charges that are produced by the bending of the piezoelectric material of the sensing units and for providing a signal indication of such bending.

Abstract: The transducer of this invention utilizes an annular lithium niobate crystal operated in the compression mode with the sensitive axis of the crystal arranged at an angle of about -51.4.degree. to the Z, or optical, axis of the crystal in the first and third quadrants of the Y-Z plane of the crystal. This accelerometer has high efficiency and operates effectively over a wide range of temperatures, including high temperatures above 1000.degree. F.

Abstract: A lithium niobate piezoelectric single crystal transducer having selected rotational orientations with respect to X, Y and Z rectangular coordinate axes. Compressional mode accelerometers having low or zero shear and torsion sensitivity are provided in which the crystal is oriented, in IRE notation, as (a) a (yxl) +38.6.degree. cut or symmetrical equivalents thereof, such as (zxl) (b) a +60.degree./+51.4.degree. cut. Shear mode accelerometers having low or zero compression sensitivity are provided in which the crystal is oriented, in IRE notation, as (a) (xyl) +31.7.degree. cut, or symmetrical equivalents, and (b) an (xyl) +76.7.degree. cut.