Abstract: An instrumented tool holder is described wherein a multicomponent force sensor embedded in said tool holder beneath the cutting insert is so oriented that the resultant of cutting forces applied to the cutting insert will pass through the approximate center of the force sensor during a machining operation.

Abstract: Differential-pressure measuring apparatus comprising a casing providing a closed chamber filled with fluid and divided into two sections by a pressure-responsive element. The input pressures are applied to the two chamber sections respectively to develop a corresponding force on the pressure-responsive element. A sealed evacuated housing of non-magnetic material is in one chamber section and contains a double-tuning-fork (DTF) the resonant frequency of which varies with longitudinal tension force applied to the DTF. The force developed by the pressure-sensitive element is coupled by magnetic elements through the wall of the housing and to the DTF so as to control the resonant frequency of the DTF in accordance with the differential pressure to be measured. The DTF is activated to produce an output signal reflecting the differential pressure.

Abstract: An improved differential pressure transducer is provided having static overpressure protection means. The overpressure protection means includes spring-loaded element being shiftable in response to an overpressure condition.

Abstract: Individual single crystal elements stacked one above the other are aligned with their optical (Z) axes parallel to each other, and are provided with contact electrodes on opposite surfaces normal to their electrical (X) axes. Contact electrodes of the same polarity are conductively connected by two bridge electrodes that are applied to opposite sides of the assembled stack of individual crystal elements in the form of a conductive coating, and are provided with a lead leaving the sensor element. Contact electrodes of the opposite polarity are recessed in the vicinity of the bridge electrode serve the other polarity.

Abstract: An AT-cut quartz resonator pressure transducer includes a generally disc-shaped resonator section, a housing surrounding the resonator section and joined to the perimeter thereof, with the walls of the housing extending in opposite directions generally normal to the plane of the resonator section. Selected portions of the sidewalls are made thinner than the remaining sidewall portions so that when the housing is immersed in a fluid, a non-uniform stress will be produced in the resonator section. The housing and resonator section are formed so that the frequency of vibration of the resonator section is substantially independent of temperature and relatively independent of temperature transients.

Abstract: A vibrating beam force transducer includes a piezoelectric beam structure supported at first and second ends, and an oscillator for inducing a vibration in the piezoelectric beam. To permit adjusting the bias frequency of the beam, an adjustment mass is formed at the center of the beam, the adjustment mass made of piezoelectric material. Part of the adjustment mass can be broken off to adjust the bias frequency. The first and second ends are attached to the a support structure by first and second legs at each end of the beam, the legs having an angle therebetween, thereby forming an A-frame mount.

Abstract: A low cost piezoresistive pressure transducer utilizing premolded elastomeric seals and adapted for automatic assembly, and a method of producing the transducer. A piezoresistive stress sensitive element in the form of a diaphram of semiconductor material having a thickened rim is held at its rim between a pair of premolded elastomeric seals in a thermoplastic housing. Electrical connections with external circuitry are made with strain relief jumpers which connect conductive regions on the element outside the seals to conductors which pass through the housing wall.

Abstract: A piezoelectric transducer including a polarized piezoelectric material film, which also has a reinforcing material incorporated into the mass and which prevents any deformation of the film in certain given directions.The invention also relates to a pressure sensor using such a transducer.This sensor can be used both as a pressure sensor and as a pressure gradient measuring device.

Abstract: A cylinder pressure transmitter has a body with a chamber open at one end accommodating pressure responsive piezoelectric means. A cup-shaped diaphragm member has a side wall secured with a laser weld to a neck portion of the body which is formed as a rim around the chamber opening. The bottom of the member extends over the opening and has a slightly domed portion exposed to the pressure in a cylinder of an internal combustion engine to serve as a diaphragm responsive to variations in cylinder pressure to apply corresponding pressure forces to the piezoelectric means, thereby to provide initial electrical signals corresponding to the cylinder pressures. Electronic means are carried on the body to amplify the initial electrical signals for transmission to computer control means at a location remote from the cylinder for regulating engine operation to improve performance.

Abstract: A thin, piezoelectric membrane provided on both surfaces with electrodes, which may be disc-shaped or ring-shaped, is made to oscillate in the piezoelectric manner and the membrane is arranged to have some exterior force or pressure applied thereto, whereby changes in the frequency of oscillation are in response to the size of the force exerted on the membrane.

Abstract: An automatic locking device for linkages subjected to undesirable mechanical stresses comprises a transducer with transmits an electrical signal as a function of the mechanical stress received, and feeds it to a coil which generates an electromagnetic field causing locking of the linkage.

Abstract: Piezoelectric polymer film, when conformably adhered to inner or outer curved surfaces of an inflated balloon, for example, acts as a speaker when the metallized coatings of the film are suitably connected to the output of an audio device. The film may be in the form of an helical strip, or individual strips elastically serially connected, or may itself form the inflatable material. Amplifying and impedance matching means may be interposed between the audio output and film coatings.

Abstract: A tactile sensing apparatus having a piezoelectric energizing layer with a plurality of conductors disposed on one surface of a piezoelectric material and a plurality of conductors disposed on the opposite surface of the piezoelectric material, the plurality of conductors having electrical connections connected to electrical energizing means. An electrical insulating layer disposed adjacent the piezoelectric energizing layer. A second piezoelectric sensing layer is disposed adjacent the insulating layer, and has conducting surfaces disposed on opposite surfaces thereof. The conductors in the piezoelectric energizing layer provide N.times.M energizing areas with N+M electrical connections to the energizing layer. Further apparatus may include an oscillator, an optional amplifier and a switching means or multiplexer for the input signal.The apparatus may optionally have more than one piezoelectric energizing layer as well as more than one piezoelectric sensing layer. PVF.sub.

Abstract: Electrodes with leads deposited on different surfaces of a piezoelectric polymeric film or films are easily and quickly electrically connected by forming a continuous channel through the film and lead to form a pierced lead, and then applying an electrically conductive material, by any one of several known processes, onto the film over the channel to thereby form a connecting lead, the conductive material being permitted to penetrate the channel to effect a continuity of conductive material between the pierced lead and connecting lead.

Abstract: A piezoelectric coaxial cable comprises a central stretchable electrical conductor (1), preferably formed from a low melting point metal alloy, a piezoelectric intermediate layer (2), preferably formed from a vinylidene fluoride polymer which has been stretched and radially polarized to render it piezoelectric, and an outer electrical conductor (3).The intermediate layer has a ratio R of its internal radius to its external radius which is preferably not more than 0.5 and especially not more than 0.4. This construction enables coaxial cables to be formed without voiding or breaking of the internal conductor during stretching.

Abstract: An electrode terminal structure for a polymer piezoelectric element is provided. The polymer piezoelectric element comprises a polymer piezoelectric film and a pair of electrode films formed on both sides of the piezoelectric film. A conductor plate and an insulating plate are successively disposed at a part near the periphery on one surface of the polymer piezoelectric film element. The thus stacked part is sandwiched between a double-layered conductor plate and the entire stacked structure is pressure bonded to form the above-mentioned electrode terminal structure.

Abstract: Disclosed is an externally loaded pressure sensor using a pair of SAW devices formed on the wall of an interior cavity. The difference frequency of these devices is used as a temperature-compensated measure of hydrostatic pressure on the sensor exterior. The termal response time of the sensor is shortened by matching to each other the sensor wall thicknesses adjacent the two SAW devices, e.g., by making these wall thicknesses approximately the same by means of forming an external flat on the sensor body.

Abstract: A load sensor includes a fixed rigid portion, a movable rigid portion spaced from the fixed rigid portion and adapted to receive an applied load, and a shear-deformable member provided between the two rigid portions. The shear-deformable portion is provided with a transmission and a reception transducer constituting an elastic surface-wave oscillator. When a load is applied to the movable rigid portion, weight is sensed based on a deviation in the oscillation frequency of the elastic surface-wave oscillator. The fixed and movable rigid portions, as well as upper and lower beams interconnecting these portions, constitute a load-sensitive element. The latter has a side face which is closed off by a pliable membrane for sealing the shear-deformable element disposed within the load-sensitivie element. Alternatively, a corrugated bellows is connected across the fixed and movable rigid portions to seal the shear-deformable member within the bellows.

Abstract: Disclosed is an externally loaded pressure sensor using a pair of SAW devices formed on the wall of an interior cavity. The difference frequency of these devices is used as a temperature-compensated measure of hydrostatic pressure on the sensor exterior. The cavity wall immediately adjacent the long sides of at least one of the SAW devices is rounded, to improve pressure sensitivity without unacceptable increase in stresses or other adverse effects.

Abstract: The invention involves the design of a piezoelectric pressure transducer d for measuring pressure-time characteristics in gun tubes during the propellent ignition and burning process. The transducer utilizes one or two Z-cut tourmaline crystals as the piezoelectric pressure sensing element which produces a finite amount of electrical charge for a given change in pressure. The tourmaline crystals are incapsulated in a mechanical fixture which provides means for mounting in the gun tube, electrical terminals for connecting to signal conditioning and recording instrumentation, and insulators for electrically insulating the transducer from the weapon ground. A needle valve is also incorporated in the transducer which provides means for replenishing the thermal protecting material around the crystal assembly without removing the transducer from the weapon.

Abstract: An improved cylinder pressure transmitter provides an electrical signal corresponding to pressure in a cylinder of an automotive internal combustion engine during engine operation and furnishes the signal to computer control means for use in regulating spark advance to improve engine efficiency and performance and reduce engine knocking. The pressure transmitter includes means for mounting piezoelectric means in sealed relation to an engine cylinder to be responsive to variations in cylinder pressure during engine operation to provide initial electrical signals representative of pressure variations in the cylinder and includes high temperature electronic means carried by the mounting means and electromagnetically shielded with the piezoelectric means within the mounting means for amplifying those initial signals to provide low impedance signals for transmission to computer control means at a location remote from the cylinder.

Abstract: An anemometer comprises an array (10) of piezoelectric pressure sensors (12), each of the sensors being mounted (e.g., on a circular mast 14) to face into a different wind direction. Electrical means are used to address each of the sensors (via contact wires (26, 28) for determining which of the sensors is generating, within a given time period, the greatest output voltage, thereby indicating the direction of the wind during such time period. In one arrangement, the amplitude of such greatest output voltage is used, via a look-up table, to determine the speed of the wind during such time period. In another arrangement, a separate, additional sensor is used to determine the wind speed.

Abstract: A touch control apparatus for an electronic keyboard instrument, comprises a sensor having: an elongated insulating sheet having a set of conductive pattern films on a surface thereof, the elongated insulating sheet being folded and the set of conductive pattern films being formed to be spaced apart from each other; and a pressure-sensitive element sandwiched in a space defined by the folded elongated insulating sheet to be in contact with the conductive pattern films. The pressure sensitive element is deformed when a key of the instrument is depressed to deliver an electrical output through the conductive films representing the magnitude of the key depression. The apparatus is superior in easiness of handling the sensor and of assembling the apparatus.

Abstract: In a piezoelectric pressure indicator comprising a casing, a pressure receiving member at the bottom of the casing, piezoelectric elements mounted on the pressure receiving member, an acceleration compensating weight and acceleration compensating piezoelectric elements, both piezoelectric elements being connected such that the voltage produced thereby cancel with each other, thereby compensating for an effect of acceleration, an uppermost acceleration compensating element is formed with a perforation, and a lead wire for deriving the voltage is connected to the electrode of a lower imperforate acceleration compensating piezoelectric element to extend through the perforation of the imperforated element. In a modification, the pressure receiving member is covered by a heat resistant protective layer made of ceramic.

Abstract: An apparatus for measuring pressure within a conduit is disclosed preferably comprising a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing the fluid to be measured through the tube; two active piezoelectric films disposed in intimate contact with the tube on opposite sides thereof; first electronic means for energizing the first of the films to cause the tube to resonate at its natural frequency, and second electronic means connected to the other of the films to monitor the frequency of the tube.

Abstract: A diaphragm-type pressure sensor employs a monocrystalline wafer as a pressure-responsive diaphragm. The wafer has a central active area surrounded by a first bonding area on one side and a second bonding area on the other side. The first bonding area is attached by a first layer of bonding material to a base, and the second bonding area is attached by a second layer of bonding material to a cap. The inside diameter of the first bonding layer is greater than the inside diameter of the second bonding layer by an amount of at least approximately six times the thickness of the diaphragm. This disparity between the respective inside diameters of the two bonding layers results in the relief of radially-directed tensile loading on the first bonding layer when a pressure to be measured is applied to the first side of the diaphragm. Consequently, the probability of a fracture occurring in this bonding layer is minimized.

Abstract: The present invention provides a barometer which includes a frequency control circuit connected to the input of the piezoelectric oscillator, a current-voltage converter connected to the output of the piezoelectric oscillator, a phase comparator connected to the output of the frequency control circuit and to the output of the current-voltage converter, a voltmeter connected to the current-voltage converter, a voltmeter connected to the phase comparator, a low-pass filter connected to the phase comparator, and input means for applying the output of the low-pass filter to the frequency control circuit. In the construction described above, the ambient pressure of the gas around the piezoelectric oscillator is represented by the a.c. voltage value of the piezoelectric oscillator.

Abstract: A cylinder pressure transmitter has means mounting piezoelectric means to provide an electrical signal corresponding to the pressure of a cylinder of an internal combustion engine and has electronic means on the mounting means to amplify the signal for transmission to computer control means for regulating engine operation to improve performance. The electronic means are mounted on an insulating substrate which is secured to a rigid support in a housing. Guide means and locating means provided on the housing and on the mounting means cooperate in mounting the housing on the mounting means and contact means on the piezoelectric and electronic means fit together in an improved manner to provide reliable interconnection between the electronic and piezoelectric means and to retain that interconnection even when subjected to engine vibrations.

Abstract: Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation.

Abstract: A transducer for detecting stress waves comprises a piezo-electric member which is mounted on a brass backing member and carried by a boron nitride support member. The piezo-electric member is deformed under the influence of stress waves to generate an electrical output, the magnitude of which is indicative of the magnitude of the stress waves.

Abstract: The invention provides a sensor comprising a plate resting on two supports by simply bearing thereon, for creating in said plate uniform bending stresses in a defined zone of said plate. Detector means for detecting the stresses undergone by said plate may be placed in said zone without their location being defined with precision.

Abstract: A cylinder pressure transmitter has means mounting piezoelectric means to provide an electrical signal corresponding to the pressure of a cylinder of an internal combustion engine and has electronic means on the mounting means to amplify the signal for transmission to computer control means for regulating engine operation to improve performance. The electronic means are mounted on an insulating substrate which is secured to a rigid support in a housing. Contact means, guide means, and locating means provided on the housing and on the mounting means cooperate to mount the housing on the mounting means to provide reliable interconnection between the electronic and piezoelectric means and to retain the interconnection even when subjected to engine vibrations.

Abstract: A cylinder pressure transmitter has means mounting piezoelectric means to provide an electrical signal corresponding to the pressure in a cylinder of an internal combustion engine. A metal diaphragm is arranged to be movable in response to variations in cylinder pressure. Rigid metal motion transfer means and rigid motion transfer means of a material of relatively lower thermal conductivity are arranged in sequence between the diaphragm and the piezoelectric means to accurately transfer movements of the diaphragm to the piezoelectric means while retarding transfer of heat from the cylinder environment to the piezoelectric means through the diaphragm. Preferably the diaphragm is formed of a clad metal laminate.

Abstract: Disclosed is a washer type pressure sensor suitable for attachment to an opening for inserting an ignition plug of an engine. The sensor is provided with a pair of ring piezoelectric elements opposed to each other through a ring electrode. A first and a second pressure receiving ring plate are disposed on an upper and a lower surface of the piezoelectric elements, respectively. The first pressure receiving plate is provided with a cylindrical protecting portion extending from the inner periphery thereof to protect an inner periphery of the sensor.

Abstract: A liquid sensor mounted on the side wall of a liquid tank for detecting the existence of liquid in the tank. The sensor includes an element which generates a vibration in the direction of its thickness, of energy-trapped type for detecting the existence of liquid. The element consists of electrodes provided on both sides of a piezo-electric substrate, one side of the element for contacting the liquid in the tank being covered with a liquid-proof coating. The existence of liquid is detected from the change in resonance impedance or antiresonance impedance resulting from the liquid contact.

Abstract: In a pressure transducer of the piezoelectric type, a resonator (10) is made up of a pellet (16) mounted inside an element designed to be subjected to the action of a pressure on its exterior face (18). The pellet (16) and the element (12) are cut in the same quartz block, using a cut which provides two vibration modes. The forces resulting from the external pressure are transmitted to the edge of the pellet (16) by connecting bridges (22, 23) whose orientation is chosen so that one of the vibration modes has maximum sensitivity to the forces while the other mode has a practically zero sensitivity.

Abstract: A piezoelectric fluid pressure fluctuation frequency sensor, preferably for a vortex-shedding flowmeter. A piezoelectric transducer is located in a sensor chamber between and in physical contact with a diaphragm and a chamber surface. Pressure fluctuations in a von Karman vortex street outside the diaphragm compress the transducer, between the diaphragm and the chamber surface. The transducer generates a responsive electrical signal which is representative of the pressure fluctuations.

Abstract: A device is provided through which a set of information concerning tactile interaction between a manipulator and an object to be recognized is provided to the user. Several configurations are described, based on the piezo- and pyro-electric (ferroelectric) properties of polymeric materials, such as the polymer polyvinylidene fluoride (PVF.sub.2 or PVDF), different polypeptides and copolymers of PVF.sub.2 and TrFE. By arraying in a proper way various sensing layers, each featured by different sensory capabilities, a laminated sensor structure is obtained, able to provide a set of tactile information. The multilayered structure of the proposed device is inspired to that of the human skin, which includes superficial (epidermal) and deep (dermal) sensors.

Abstract: A piezo-electric transducer type pressure sensor such as a silicon pressure sensor or the like is provided in a low path of fluid located in the midway between a valve section and a nozzle ejection port in a fluid ejection gun. When foreign matters in the fluid block the nozzle and hence the ejection from the nozzle becomes an abnormal condition, a fluid pressure variation produced in the flow path between the valve section and the nozzle ejection port is detected in the form of an electric signal by means of the piezo-electric transducer type pressure sensor.

Abstract: A quartz resonator pressure transducer includes a generally disc-shaped resonator section, a housing surrounding the resonator section and joined to the perimeter thereof, with the walls of the housing extending in opposite directions generally normal to the plane of the resonator section. Selected portions of the sidewalls are made thinner than the remaining sidewall portions so that when the housing is immersed in a fluid, a non-uniform stress will be produced in the resonator section. The housing and resonator section are formed so that the frequency of vibration of the resonator section is substantially independent of temperature and relatively independent of temperature transients.

Abstract: In a piezoelectric transducer (10) an external element (12) of tubular form receives a pressure, notably a pressure to be measured, on its external face (16). It is cut in a quartz crystal in one piece with a plate (25) capable of vibrating under the action of an electric stress and extending in a plane parallel to the longitudinal direction of the tubular element inside the latter. Each of the longitudinal edges of the plate is connected by a transverse connecting element (30, 31) to the internal face (14) of the tubular element so as to transmit forces (F1 and F2) resulting from the application of the external pressure to the plate (25) in a direction substantially parallel to its plane and perpendicular to the axis of the tubular element (12).

Abstract: A piezoelectric force/pressure sensor capable of detecting the magnitude of static and dynamic force or pressure applied thereto, utilizes first and second transducers each having a piezoelectric member with opposed first and second surfaces; an electrode fabricated upon each of the first and second surfaces of each of the first and second piezoelectric members; and a member fabricated of a material of known resiliency having first and second opposed surfaces each attached to one of the electrode-bearing first and second surfaces of a different one of the piezoelectric transducers. A first of the piezoelectric transducers is excited to vibrate in the thickness mode. The vibrations are coupled through the interposed elastic middle layer and are transformed to provide an electrical output from the sensor which is responsive to the force/pressure applied along the axis of the transducer-resilient member-transducer sandwich.

Abstract: A mechanism for converting a weight into a frequency by means of a tuning fork vibrator having a pair of elongated plate-like vibrating strips extending in parallel with each other, a lever unit with a power pivot, fulcrum pivot and a load pivot, and a base portion, both ends of the tuning fork vibrator being coupled with the power pivot of the lever unit and the base portion, respectively by means of thin plate-like members. The weight to be converted is applied to the load pivot of the lever unit and is transferred to the tuning fork vibrator by means of the lever unit. All the parts of the mechanism are formed integrally from a single plate.

Abstract: An integrated array of pressure transducers capable of producing an analog output voltage representative of the applied pressure is proposed. The individual transducing elements (16) are defined by a three-layer structure including a thin layer of piezoelectric material (10) disposed between a reference potential plate (12) and a plurality of electrodes (15) contained in a silicon substrate (14). A force applied to a localized portion of the reference plate will cause a deflection of the piezoelectric material towards the electrodes on the substrate, inducing a capacitive charge on the electrode in the localized area. This capacitance is stores at a node A associated with the transducing element, and may be interrogated by a sensing circuit (18) located in the silicon substrate. Since the induced charge is directly proportional to the applied force, a measurement of the output voltage from node A will yield a direct indication of the localized force applied to the sensor.

Abstract: Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation.

Abstract: Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation.

Abstract: A method and apparatus for measuring force or other parameters and temperature. The apparatus includes an oscillator and a vibratory element, such as a quartz crystal, which is caused to resonate by the oscillator at two frequencies f.sub.1 and f.sub.2 selected from the fundamental frequency and its overtone frequencies of the vibratory element. The vibratory element is selected so that the two frequencies f.sub.1 and f.sub.2 both vary with variation in force (or other parameter) applied to the element and with variation in temperature of the element, and so that the magnitude or scale factor of variation for frequency f.sub.1 is different from that for frequency f.sub.2. The apparatus also includes a detection device for detecting the frequencies f.sub.1 and f.sub.

Abstract: Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation.

Abstract: A multilayer electrostrictive element has electrostrictive sections (31) defined by internal electrodes (32) in a stack, with a peripheral surface which has a predetermined outline perpendicularly of an axis of the stack, each internal electrode with an outline which is approximately congruent with the predetermined outline (constant cross-section). In order that external electrodes (33, 34) may readily be connected to the internal electrodes grouped by twos, each internal electrode may have a peripheral end which is partly recessed from the predetermined outline, as in FIG. 8. Alternatively, the internal electrodes of each group may be connected together by a conductor rod which passes through the electrostrictive sections, preferably along their edges, contacting alternate electrodes. For a great number of internal electrodes, an element may be manufactured by laminating conductive-paste-printed green sheets transversely of the stack axis and then sintering the lamination.

Abstract: Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation.