Abstract: A cable puller is provided to pull rope or cable where the cable puller includes a puller frame, a capstan rotatably mounted on the puller frame around a first axis of rotation, an output shaft rotatably mounted to the puller frame and coupled to the capstan, The capstan is configured to rotate when the output shaft is driven. A shift motor is configured to drive a cam to engage gearing coupled to the output shaft to a gear position comprising a low speed position, a medium speed position, and a high-speed position.

Abstract: A control assembly for selectively controlling actuation of an electric motor arranged to power a hand-held power tool based on combined performance of two dissimilar operator actions and a hand-held power tool including such a control assembly. A switch member may be closed responsive to an enabling action including a first of the two dissimilar operator actions. A throttle control member becomes operable responsive to actuation of the throttle control member past a first movement threshold, i.e. a second dissimilar operator action, while the switch member is in the actuated state. The throttle control member remains repeatedly operable above a second movement threshold, even if the switch member is opened. Actuation of the throttle control member to below the second movement threshold will render the throttle control member non-operable until renewed combined performance of the first and second dissimilar operator actions.

Abstract: A rotor for a vertical axis wind turbine generator features a flywheel having first and second faces located opposite one another across a thickness of the flywheel, and a circumferential perimeter edge joining the first and second faces together around the central axis at a perimeter of the flywheel. A series of cavities are spaced radially inward from the circumferential perimeter edge and open into the flywheel from the first face on a path disposed circumferentially about the central axis. A series of permanent magnets carried in the cavities have the opposing poles of adjacent magnets facing in the same axial direction. The recessed magnet configuration avoids the separate magnet-retention means required for flush-mount configurations, and increases the performance of the generator.

Abstract: The invention relates to a magnetic coupling assembly for associating a first rotatable shaft to a second rotatable shaft, the magnetic coupling assembly comprising:—a rotatable first hub to be connected to the first rotatable shaft, the first hub comprising a magnet rotor comprising a plurality of permanent magnets;—a rotatable second hub to be connected to the second rotatable shaft, the second hub comprising a conductor housing comprising at least one conductor positioned at a distance from a side of the magnet rotor facing the second rotatable shaft; wherein at least one of the second hub and first hub comprises an inner hub part and an outer hub part, wherein the hub parts are configured to allow the outer hub part to be axially movable over the inner hub part to adjust the axial position of the at least one conductor relative to the magnet rotor.

Abstract: The present invention discloses an electronic inductance circuit for the power supply of a 2-wire bus intercom system and a device thereof. The electronic inductance circuit comprises a main circuit path along an inductor and a source terminal and a drain terminal of a FET between the input terminal and the output terminal of said electronic inductance circuit, in which said inductor is connected to said source terminal of said FET; a resistor and a freewheeling diode individually connected to said inductor in parallel; and a secondary circuit path along a capacitor connected with a second resistor in series between said input terminal and said output terminal, which is connected to said main circuit path in parallel. The solutions of the present invention achieve larger direct current power supply for the 2-wire intercom system and stable alternating current impedance with fast response to the DC power supply.

Abstract: A press machine includes a controller including a top-dead-center detector adapted to: rotate a main shaft in a predetermined direction selected from a normal rotation direction and a reverse rotation direction to place a slide at a first position displaced relative to a top dead center of the slide by a predetermined height; while outputting and counting pulses from an angle detector, rotate the main shaft in a direction opposite to the predetermined direction to move the slide to a second position located at the same height as the first position beyond the top dead center; and rotate the main shaft from the second position in the predetermined direction by an amount corresponding to a half of the counted pulses to detect the top dead center.

Abstract: This invention describes a method by which Broadband Spectrum Analysis can be performed in the RF and Microwave frequency range with significantly higher speed, accuracy, and flexibility than existing RF and Microwave Spectrum Analyzers. This is done by eliminating the need for the filtering of the incoming signal, a process called preselection that needs to track in frequency with the scanning local oscillator in the instrument. By eliminating this requirement, this invention makes possible the identification and analysis of very broadband signals in a single sweep using an Adaptive Sweep Methodology and a Simultaneous Sweep capability that the present invention makes possible.

Abstract: A roller device for a traction mechanism drive, with a roller element for introducing a torque provided via the traction mechanism and a driven shaft for driving an auxiliary unit of a motor vehicle. The roller device further has a magnetic coupling for torque transfer between the roller element and the driven shaft. The magnetic coupling has a primary-side unit connected to the roller element having a primary magnetic element and a secondary-side unit connected to the driven shaft with a secondary-side magnetic element. The magnetic elements are permanent and/or electromagnetic elements and the torque transfer is realized by magnetic fields of the primary and secondary-side magnetic elements. At least one magnetic element of the two units for changing the magnetic field overlap of the magnetic fields of the primary and secondary-side magnetic elements is arranged movably within its unit by the centrifugal forces occurring during operation.

Abstract: A magnetic-controlled actuator (100) with an auto-locking function for joints of a manipulation arm mainly includes an inner-layer stator (10), an inner-layer mover (20), an outer-layer mover (30), an outer-layer stator (40), and a fixing shaft (50). The inner-layer mover (20), the outer-layer mover (30), and the outer-layer stator (40) have a plurality of permanent magnets, respectively. The fixed shaft (50) simultaneously penetrates through the inner-layer stator (10), the inner-layer mover (20), the outer-layer mover (30), and the outer-layer stator (40) forming a coaxial arrangement. The inner-layer mover (20) rotates relatively to the inner-layer stator (10) to output power from the actuator (100). Therefore, a cogging effect, which is produced due to interaction of the permanent magnets between the outer-layer mover (30) and the outer-layer stator (40), is automatically produces a high cogging torque for the actuator (100).

Abstract: An enhanced dual rotational electric motor/generator includes an armature that rotates about a central axis in one direction, a stator that rotates about the central axis in an opposite direction, an axle that extends along the central axis and is secured to the armature, an axle support, a rotational output alignment mechanism for converting the opposite rotations of the armature and stator into a common rotational output direction, and an electrical connection mechanism that supplies functioning electrical communication between the motor/generator and external electrical circuitry while operating the motor/generator.

Abstract: An electrical machine with torque limitation which is only slightly larger structurally than an identical machine without torque limitation and is thus as compact as possible has a stator with windings and a rotor supported movably relative to the stator, recesses distributed over the circumference and extending axially are present on the rotor surface, and a driver, located coaxially relative to the rotor and extending axially, is located in the air gap between the rotor and the stator, and exciter magnets on the upper driver face toward the stator and driver magnets on the inner driver face toward the rotor are located in such a way that upon rotation of the driver, the rotor is likewise capable of being set into rotation as a result of the rotary field generated by the windings and by the driver magnets.

Abstract: A bearing (32) for a coordinate measuring instrument including a slide (36) which can be axially displaced in relation to a fixing device (34) and which can be supported opposite the fixing device by means of at least one air bearing (38, 40). In order to be able to utilize the bearing for all axes of the coordinate measuring instrument while simultaneously using outer surfaces of the slide as mounting surfaces for sensors, the invention provides that a force that works counter to the air bearing can be generated by a magnetic field (42, 44).

Abstract: The present invention provides a method and system for stabilizing a rotor about its geometric center in a magnetic bearing system at a constant rotor speed. In the method, the controller for controlling the magnetic bearing uses an adaptive control algorithm which simultaneously identifies and compensates for synchronous sensor runout and rotor mass unbalance while determining a control action that drives the rotor rotating at a constant speed to its geometric center. The identification of sensor runout and mass unbalance is by varying the magnetic stiffness which is achieved by perturbation of the bias currents in opposing electromagnet coils in a manner that does not alter the equilibrium of the rotor while it is rotating at a constant speed.

Abstract: A drive for the compressor of a vehicle air conditioner has a magnetic clutch for mechanically driving the compressor shaft within a predetermined range of torque and a rotatable input element on the magnetic clutch to be rotated by the vehicle motor at varying speeds with changes in the vehicle motor's speed. The drive includes a first electromagnetic element on the rotatable input element and a compressor shaft on the output side of the magnetic clutch for supplying torque to drive the compressor. Also, there is a second electromagnetic element on the compressor shaft with a magnetic field between the first and second electromagnetic elements to rotate the compressor. An electric control is provided for varying the electrical power to the electromagnetic clutch as the vehicle motor changes speed to vary the magnetic field and torque being applied to rotate the compressor shaft.

Abstract: An actuator for an HVAC system includes a motor coupled by an electrically operated clutch to a gear train which drives an output connector. A spring is connected to the transmission to drive the output connector to a normal position in the event of a power failure. A control apparatus is connected to the transmission and provides the combined functions of a magnetic eddy current brake and a motion sensor.

Abstract: A motor, encoder/resolver, and/or dynamic brake assembly in which the dynamic brake, when part of the assembly, is mounted on a rear cover plate of a modular housing for the auxiliary components. When a resolver or encoder is part of the assembly, the motor shaft extends only a short distance beyond the resolver/encoder housing module; far enough to be engaged by the armature of the dynamic brake if the brake is part of the assembly. In an assembly that does not use a dynamic brake, the same rear cover plate is used to close the encoder/resolver housing module.

Abstract: A method for fabricating piezoelectric resonators on a substrate such that the resonant frequency of one resonator is shifted by a small amount from another of the resonators. By means of differential fabrication of the electrodes, the thickness of the metal in an electrode for one resonator is increased relative to that of another resonator to obtain the shift in resonant frequency. The frequency of a single resonator also may be adjusted to a specific frequency by the addition of a differential layer of metal to one of the electrodes comprising the resonator. Mask alignment errors in the differential fabrication process cause non-uniformities in the thickness of the metal in the electrode which non-uniformities significantly degrade the performance of the resonator. The areas of non-uniform thickness of electrode that degrade the performance are removed in this process.

Abstract: An eddy current drive has an electromagnet and an armature. Either one of the electromagnet or the armature is coupled to a motor shaft so as to rotate therewith, while the other is coupled to a load portion. The motor can rotate at a continuous speed, while the speed of the load portion can vary by varying the energization of the electromagnet, so as to vary the coupling between the electromagnet and the armature. The rotation of the motor shaft generates electrical current that is used to energize the electromagnet. The amount of the electrical current that is provided to the electromagnet can be varied to vary the output speed of the load portion. The electrical current can be generated by a member that rotates in unison with the electromagnet. A rotary coupler provides a speed control signal to vary the amount of current that is provided to the electromagnet. The rotary coupler can also provide power from the rotating generator to a stationary controller.

Abstract: An eddy current drive has an electromagnet and an armature. Either one of the electromagnet or the armature is coupled to a motor shaft so as to rotate therewith, while the other is coupled to a load portion. The motor can rotate at a continuous speed, while the speed of the load portion can vary by varying the energization of the electromagnet, so as to vary the coupling between the electromagnet and the armature. The electromagnet is energized by way of bearings. The bearings provide a rotary coupling. In another embodiment, an electrical generator is provided. The rotation of the motor shaft generates electrical current that is used to energize the electromagnet. The amount of the electrical current that is provided to the electromagnet can be varied to vary the output speed of the load portion.

Abstract: A brushless shaft mounted eddy current drive has a coil mounted to bearings by way of a coil mount. The bearings are located on a hub. The coil mount is anchored to a fixed object. The pole pieces are coupled together by a nonmagnetic material to form a cavity that receives the coil. In another embodiment, a brushless drive has a coil rotatably mounted in a cavity within the pole pieces. A rotary inductive coil is mounted to the pole pieces about a stationary inductive coil. Alternating current is provided to the stationary coil to induce current into the rotary coil. In still another embodiment, an alternator is used to induce current into the rotating coil. In still a further embodiment, a brushless drive incorporates a liquid conductive rotatable coupler in the hub. In still another embodiment, the brushless drive energizes the coil in the electromagnet by way of bearings. The bearings are mounted onto a shaft that is coupled to the electromagnet.

Abstract: An electric variable speed drive includes a hub member, a driven member, a magnetic coupler, and a rotary electrical connector. The hub member is mounted for rotating with the shaft of a prime mover. The driven member is rotatably supported on the hub member by bearings, and includes a mechanical output portion such as a pulley. The magnetic coupler includes an electric coil and magnetic poles which are mounted for rotating with one of the hub and the driven members. An armature is mounted to the other of the hub and driven members. An electric current is passed through the electric coil to magnetically couple the hub member to the driven member. The extent of the magnetic coupling between the hub and driven members is determined by the electric current passing through the electric coil.

Abstract: A drive has a hub with first and second end portions and a shoulder located thereon. An armature and sheave assembly is located on bearings on the hub first end portion. The armature forms a cavity for receiving an electromagnet, which abuts against the shoulder. Slip rings are coupled to the electromagnet by way of a fan and a slip ring shaft. The slip rings, which are adjacent to the second end of the hub, can be of a small diameter to extend brush life. In addition, the same size slip rings can be used on different sizes of the drive. Two piece brush holders are provided for each brush. Each brush holder can be disassembled into its respective pieces for cleaning. The brush holders and slip rings can be protected from the environment by a cover.

Abstract: A brushless shaft mounted eddy current drive has a coil mounted to bearings by way of a coil mount. The bearings are located on a hub. The coil mount is anchored to a fixed object. The pole pieces are coupled together by a nonmagnetic material to form a cavity that receives the coil. In another embodiment, a brushless drive has a coil rotatably mounted in a cavity within the pole pieces. A rotary inductive coil is mounted to the pole pieces about a stationary inductive coil. Alternating current is provided to the stationary coil to induce current into the rotary coil. In still another embodiment, an alternator is used to induce current into the rotating coil. In a still further embodiment, a brushless drive incorporates a liquid conductive rotatable coupler in the hub.

Abstract: In an electrically-powered tool, the driving motor of the tool and a switching element for a phase control circuit for controlling the number of revolutions of the motor are connected in series. The switching element is fixed to a field core of the motor. In the phase control circuit for the switching element, a bias resistance between the base and the emitter of a pulse phase controlling transistor for changing the amplification degree by the output from a pulse generating circuit for generating pulses having frequencies corresponding to the numbers of revolutions of said motor is connected in parallel with a capacitor for effectively slowly starting said motor, a first amplifier for changing the output in response to the number of revolutions of said motor and for stabilizing the rotation of said motor, and a second amplifier for producing output upon falling of the number of revolutions of said motor below the preset number of revolution and for limiting overload current.

Abstract: A shaft mounted eddy current variable speed drive or clutch has a hub which is adapted to be mounted on the shaft of a prime mover, such as an electric motor, and drives an armature. The hub includes an annular armature. A driven magnetic body is mounted for rotation on the hub and includes an array of poles magnetically associated with the armature through a working air grap and are energized from an electric coil mounted on the magnetic body. A slip ring assembly is also mounted on the magnetic body as well as an output pulley through which power is taken from the body. A non-rotating brush holder assembly, as well as a magnetic speed pick-up are mounted on a support bracket which bracket is, in turn, piloted to and mounted on the hub through a bearing. A torque arm prevents the rotation of the brush assembly and magnetic pick-up.

Abstract: The invention is an improved control mechanism for winches as used on cranes and similar devices having a single motor driving the shaft of a winch drum through a pair of eddy current clutches. Gear trains attached to the two clutches are operative to drive the drum's shaft in opposite directions. An electronic control generates an output signal indicative of a commanded speed and direction of drum rotation while a tachometer generates a signal indicative of the actual speed and direction of drum rotation. The electronic control system compares the commanded and actual speed as well as the direction of rotation and generates signals energizing the two clutches. The combined action of the two clutches stabilizes the rotational speed of the drum and its direction of rotation in accordance with the commanded input.

Abstract: An apparatus for generating a pulse train depending on the speed of a rotary system. The external field of a coupling magnet in a slipping clutch in the rotary system is sensed to provide a measure of speed.

Abstract: A control circuit for controlling the shaft speed of a motor having clutch and brake devices comprises a speed detector for detecting the actual rotating speed of the motor and generating a first pulse signal having a period in inverse proportion to the actual rotating speed, a speed selector for setting the desired-speed of the shaft, a signal generator for generating a second pulse signal having a period in inverse proportion to the desired-speed from the speed selector, a first means for detecting the ratio of the period of the first signal to the period of the second signal, and a second means for controlling the operation of the clutch and brake devices in response to the detected ratio.

Abstract: An elastic surface wave device comprises a substrate of dielectric material, a thin layer of piezoelectric material, a plurality of electrodes and a thin layer of dielectric material. The piezoelectric layer is spaced from the electrodes with the thin dielectric layer formed therebetween and is so arranged as to facilitate the employment of a known photo-etching method to form the electrodes.

Abstract: Quartz crystal vibrators of small size which vibrate in the shear mode consist essentially of a vibrating portion and a support portion, both of which lie in the same plane. As a consequence, they are readily manufactured on a production basis and can be shaped so as to minimize the effect of variation in ambient temperature.

Abstract: An automatic electronic remote control system is provided which is particularly adapted to control the operation of clutches for a hydraulic torque converter in a vehicle. Responsive to operating conditions, the system produces different control signals depending on whether the ratio of the frequencies of two series of pulses is above or below a predetermined value, the pulse frequencies being related to the rotational speeds of the input and output axes of the converter. The system includes two n-bit binary ring counters which respectively receive the two series of pulses, one of the countersbeing effective to control the other so that a signal representing the actual value of the ratio in question is produced in binary form. This signal is decoded to produce the control signal referred to above.

Abstract: A device for converting electric into acoustic vibrations and vice versa, provided with a diaphragm, comprising at least one layer of a piezoelectric polymer material, which is polarized in a transverse direction and which at either side is provided with electrodes, the diaphragm being undulated in at least one orthogonal section, whilst each flank of the undulation is polarized in the same direction over its entire width and in the operating condition the direction of the applied electric field relative to the direction of polarization in adjoining flanks are alternately parallel and anti-parallel. Two types of embodiments are possible.

Abstract: An electro-mechanical transducer comprises a LiNbO.sub.3 -piezoelectric substrate containing as an impurity at least one material selected from the group consisting of Ta, Ta.sub.2 O.sub.5, Pd, SiO.sub.2, TiO.sub.2, V.sub.2 O.sub.5 and V, and at least two electro-mechanical transducing interdigital electrode pairs, provided on said LiNbO.sub.3 -piezoelectric substrate.

Abstract: A piezoelectric transducer element which can be used in force and pressure transducers is made from a quartz element which is prestressed within the transducers. The prestress is applied within a certain orientation with respect to the lattice plane (0 4 4 3). The transducer may include both disc and rod-shaped quartz elements.

Abstract: A bulk wave acoustic wave device with electrodes fabricated on a crystal in the form of arrays each having a plurality of closely spaced electrodes, one array being angularly disposed with respect to the other to provide at least one pair of matching electrodes notwithstanding uncontrolled beam wander within the crystal.

Abstract: A bulk acoustic wave delay line including a body of acoustic wave supporting material and having at least one planar surface capable of reversably converting longitudinal wave mode acoustic energy to shear wave mode acoustic energy, the delay line also including at least one transducer for converting electromagnetic wave energy to acoustic wave energy and vice versa for propagating said acoustic wave energy along a path, a major portion of which supports shear wave mode energy and which path is at least partially defined by the mode converting planar surface, the planar surface being treated to increase the attenuation of propagating acoustic wave energy thereat by a predetermined amount, the attenuation provided at said planar surface being relatively frequency independent as compared to the attenuation per unit time of the propagating acoustic wave energy in the delay line body whereby triple transit signal suppression is significantly increased while still maintaining a relatively wide band frequency respo

Abstract: This disclosure concerns a particularly oriented plate-like monocrystalline piezoelectric body of lithium niobate for use as a substrate in an acoustic surface wave filter device, wherein the orientation of the piezoelectric body of lithium niobate is responsible for a substantial reduction in spurious responses including plate modes. More specifically, the piezoelectric body comprises a plate of lithium niobate having a crystalline lattice orientation as determined by a 46.degree. (ZYW) cut. It has been determined that such a piezoelectric body may be employed as a substrate in an acoustic surface wave filter device to effect an improved filter response in that unwanted spurious responses including those caused by plate modes are removed or substantially reduced from the acoustic signals prior to their conversion into electrical output signals.

Abstract: In acoustic surface wave devices the bottom of the substrate is provided with a plurality of discrete recesses to attenuate and/or scatter bulk waves.

Abstract: An electro-acoustic transducer with a piezoelectric diaphragm supported by a support member having a curved portion for imparting a suitable resiliency and/or tension to said diaphragm to improve acoustic characteristics without reducing efficiency of the electro-mechanical conversion effected by the transducer.

Abstract: Disclosed is a method for fabricating an acoustic surface wave device having reduced temperature coefficient of propagation delay within a desired range of operating temperatures. In one embodiment the device includes a piezoelectric substrate comprising X-propagating Y-cut quartz having a cut angle at which point of zero temperature coefficient of propagation delay is at a temperature which is higher than the desired range of operating temperatures. There is included on the substrate in the desired path of the propagating surface wave a deposit of conductive material which has the effect of lowering the temperature at which the point of zero temperature coefficient of propagation delay occurs, thereby reducing the magnitude of the temperature coefficient of propagation delay within the desired range of operating temperatures.

Abstract: The particular anisotropy of a specific propagation surface orientation on a single crystal lithium tantalate substrate member is utilized to achieve low diffraction, low spurious response surface acoustic wave (SAW) propagation. The preferred embodiment utilizes a propagation surface that substantially coincides with a plane defined by the Euler angles Lambda = 0.degree., Gamma = 166.65 (+0, -0.3).degree., and Theta = 90.degree..

Abstract: A piezoelectric electro-acoustic transducer which includes a support means, a piezoelectric diaphragm supported at its edge portions by the support means comprising at least a pair of fixing members arranged to oppose each other, and a resilient backing member brought into a contact with the diaphragm to impart to the diaphragm a suitable tension and/or resiliency. The resilient backing member has an area smaller than the substantial vibration area of the diaphragm so that portions of the diaphragm are left free from contact with the resilient backing member, whereby, it has become possible to improve the frequency characteristics and consequently obtain improved sound characteristics.

Abstract: A wafer of lithium niobate metallized on both major surfaces is bonded to a magnesium aluminate spinel bulk acoustic delay line. The lithium niobate layer is divided into two separate electrically and mechanically isolated transducers using ion beam milling. The bulk acoustic delay line has a surface arranged to reflect a propagating acoustic wave generated by one of the divided transducers to the other of the transducers, the one transducer serving as an input and the other as an output. The acoustic delay line is suitable for broad band operation at microwave frequencies with at least 50 db isolation between the two ports.

Abstract: Disclosed is an acoustic surface wave device having reduced temperature coefficient of propagation delay within a desired range of operating temperatures. In one embodiment the device includes a piezoelectric substrate comprising X-propagating Y-cut quartz having a cut angle at which point of zero temperature coefficient of propagation delay is at a temperature which is higher than the desired range of operating temperatures. There is included on the substrate in the desired path of the propagating surface wave a deposit of conductive material which has the effect of lowering the temperature at which the point of zero temperature coefficient of propagation delay occurs, thereby reducing the magnitude of the temperature coefficient of propagation delay within the desired range of operating temperatures.

Abstract: An acoustic surface wave device is disclosed which comprises a crystal of Tl.sub.3 VS.sub.4, Tl.sub.3 NbS.sub.4, or mixtures thereof having at least one surface at least 1/2 cm long, a surface wave generating transducer mounted on the surface, and a surface wave receiving transducer mounted on the surface positioned to receive a surface wave generated by the surface wave generating transducer.The device transmits surface waves at a low velocity and high coupling efficiency and can be used in a delay line, a filter, an FM discriminator, an oscillator, or other device.

Abstract: At least three pairs of opposing electrodes on the two major faces of a poelectric or electrostrictive transducer element having a gap which is adapted to change in response to selected control voltages applied across the three pairs of electrodes. The pairs of electrodes are electrically insulated from one another and one pair of electrodes covers substantially one half of the major faces across from the gap, while the other two pairs of electrodes are disposed on the major faces of the transducer adjacent the gap and respectively covering substantially quarter sector portions of the transducer surface. By the mechanical bonding of electrical switch contacts for example to the opposing end faces at the gap, switch actuation is provided by the application of control voltages across all three pairs of electrodes, causing the gap to diminish and thereafter shorting the pairs of electrodes or applying a reverse control voltage to widen the gap.

Abstract: An elastic surface wave propagation device is disclosed which is composed of a substrate for elastic surface wave propagation and at least one transducer disposed on the major surface of the substrate for converting an electric signal into an elastic surface wave or vice versa. The substrate is formed of quartz crystal and the major surface of the substrate is 43.degree. rotated Y cut plane of the quartz crystal. The angle between the direction of propagation of the elastic surface wave and the X-axis direction of the quartz crystal is selected to be in the range of 8.degree. to 12.degree. so that spurious components are sufficiently suppressed or negligible.

Abstract: An acoustic surface wave device comprising a monocrystalline body of piezoelectric material having a launching and receiving transducer applied to a planar ASW propagation surface. The piezoelectric material and the orientation of the propagation surface and the axial propagation direction relative to the crystal axes are selected to provide zero piezoelectric coupling between the transducers and a longitudinal axial bulk wave and that one of the two shear axial bulk waves that has substantially no component of particle motion perpendicular to said propagation surface. A method of manufacturing the aforesaid ASW device is also disclosed.

Abstract: A small low frequency acoustic receiver which is formed into a cylinder or ing by use of a plurality of separate elements of piezoelectric material. Each element is secured with its sides in face-to-face relationship with an electrode between each joined face in contact with each adjacent element. The electrodes are alternately connected into an electrical circuitry for transmitting electrical signals to a receiver.Other construction techniques may be used to assemble separate elements in a cylindrical arrangement. Over a band of very low frequencies, the cylinder or ring has a high sensitivity (i.e., it produces a large electrical signal) to sound incident in the axial direction compared with its sensitivity in the radial direction. Over this band of very low frequencies the sensitivity of the cylinder or ring is relatively constant for sound incident in the axial direction.

Abstract: A cutterhead assembly suitable for forming a topographic signal-representative pattern in a recording medium such as a disc is constructed with non-parallel external surfaces so as to provide a response relatively free of undesired resonant modes over a relatively wide frequency range. The cutterhead includes a cutting stylus supported in a stylus mount. The stylus mount and therefore the stylus are driven by a piezoelectric element which is mounted on a supporting pedestal. A resilient mounting means is utilized to fasten the supporting pedestal to a mounting bracket.