Abstract: In a position detecting device which detects a piston rod based on the time elapsed from a point at which an ultrasonic wave is emitted from an ultrasonic wave sensor toward a lower end surface of the piston rod reciprocatingly moved linearly by supply and discharge of a working oil with respect to a hydraulic cylinder to a point at which the ultrasonic wave reflected by the lower end surface of the piston rod is received by the ultrasonic wave sensor, if the working oil's temperature is detected by a temperature sensor, then a microcomputer sets the strength of the ultrasonic wave emitted from the ultrasonic wave sensor in accordance with the temperature of the working oil so as to accurately detect the position of the piston.

Abstract: A fixing member is inserted under pressure into a central hole of an ultrasonic vibrator, a case and a center axle are fixed by a screw, a bearing is fixed on an end portion of the center axle, a rotor is mounted to rotate by the bearing, a connection member is fixed to the rotor, projections are formed on the edge of a disk of the connection member, spaces are formed between the projections respectively, a contact member is composed by inserting ends of divided parts into spaces of the connection member, and a ring-like elastic member is mounted on the contact member which is pressed on the ultrasonic vibrator.

Abstract: A sensor chamber is formed a side portion of a liquid supply inlet of a housing, a sound pressure sensor is mounted in the sensor chamber, ultrasonic waves from an ultrasonic vibrator provided in the housing are detected by the sound pressure sensor, and a defect of the ultrasonic vibrator is detected when the output of the sound pressure sensor becomes less than a predetermined value.

Abstract: Two digital reflectional signals of different depth ranges are displayed on two divided pictures in a display, whereby the conditions of the water and the bottom in the lake or pond can be detected. Therefore, the fish sonar is suitable for fishing for black bass.

Abstract: Reflected digital signals of a surface of the water, fish and a bottom are displayed by a usual scale on a half portion of the display board, reflected digital signals of fish and a bottom are reversely read from the second buffer function and are displayed at an enlarged scale on a second half portion of the display board, whereby the surface of the water is displayed on the upper portion of the display board and the bottom of the water is displayed on the lower portion of the display board and the flasher display is very easy to understand and fish inhabiting near the bottom and the bottom are displayed on an enlarged scale.

Abstract: An ultrasonic wave having a narrow directive angle and an ultrasonic wave having a wide directive angle are transmitted in water by two ultrasonic transducers, echo signals to the ultrasonic waves having the narrow and wide angles are displayed by the two luminous elements in unity in a flasher display, whereby the condition of fishes in the water can be seen widely.

Abstract: A plurality of small bubbles are continuously generated by transmitting to washing water in a vessel, a high frequency ultrasonic wave from an ultrasonic vibrator which generates a high frequency output from a high frequency oscillator and intermittently transmitted low frequency ultrasonic waves from ultrasonic vibrators wherein the intermittent low frequency ultrasonic waves are produced from low frequency outputs from low frequency oscillators for short periods of time. The plurality of small bubbles are destroyed by the intermittent ultrasonic waves and the pressure from the sound of the ultrasonic waves in the washing water is thereby increased and washing performance is improved.

Abstract: Intervals of timing pulses generated by a timing pulse generating means are changed by an interval changing means, interference signals from a second vibrator having the same intervals of the timing pulses being eliminated by changing the interval of the timing pulses by the interval changing means.

Abstract: The present invention is directed to an ultrasonic driving member comprising a rotor having slide projections in contact with an edge face of a piezoelectric vibrator.

Abstract: A drive circuit is used in a Langevin type ultrasonic bolt-tightening motor in which a motor drive voltage having a given frequency is applied to a piezo-electric element in a stator section, the resulting longitudinal and torsional vibrations being effective to rotate a motor section. The drive circuit has a longitudinal vibration sensor for detecting the longitudinal vibration in the stator section, a torsional vibration sensor for detecting vibration in the stator section and a frequency controller for controlling the frequency of the motor drive voltage such that the phase difference between the detection signals of the longitudinal and torsional vibration sensors becomes 90 degrees so as to provide maximum efficiency. Thus, the frequency of the motor drive voltage can be feedback controlled to maintain an optimum drive frequency despite the varying of the optimum drive frequency due to changes in various factors.

Abstract: Ultrasonic waves of a low frequency and a high frequency are alternately emitted from one vibrator to liquid in a tank, cavitation generated due to the ultrasonic wave of the low frequency is eliminated and changed to small cavitation for forming the next large cavitation due to the ultrasonic wave of the high frequency and next the ultrasonic wave of the low frequency is emitted to the liquid in a tank and large cavitation is formed, whereby the cleaning effect is improved.

Abstract: When output signals of different multi-frequencies are supplied to one vibrator every short time interval, ultrasonic waves generating from the vibrator having continuing frequencies in which frequencies between separated resonance frequencies are supplemented. Therefore, the cleaning effect is improved by the ultrasonic waves.

Abstract: In the present invention, an electrode in both end portions of a piezoelectric vibrator is respectively divided in two, alternative current voltage is supplied to each of electrodes of the both end portions, whereby reversible circumferential progressive wave arises on the both end portions or side portion of a state consisting of the piezoelectric vibrator. A member to be driven is composed on each of the both end portions or the side portion of the stator.

Abstract: A stator is composed by two metal blocks, a piezoelectric vibrator and vibrators, and two electrodes, in which one electrode is divided in two at least, the metal blocks, the piezoelectric vibrator or vibrators and two electrodes are fixed by means of a bolt or means of adhesive thing, and a member to be driven composed on the nut or the end or side portion of the stator.

Abstract: A rotary member rotatably supports a plurality of balls, disks or rolls which are pressed on a stator by a pressure member. When the stator generates progressive wave, the balls, disks or rolls are rolled on the stator and the pressure member by the progressive waves. Since the balls, disks or rolls are rolled on the stator and the pressure member, the wear of the stator, the pressure member and the balls, disks or rolls is decreased. Lubricative oil may be applied to the circumference of the balls, disks or rolls of the rotary member.

Abstract: A stator consists of a cylindrical piezoelectric vibrator and electrodes respectively divided in two in its inside and outside portions. When alternative current voltage is applied to respective one of divided electrodes in the inside and outside portions, reversible progressive waves generate on the end and side portions of the stator. When a rotary member is combined with the end or side portion of the stator, the rotary member can reversibly be moved.

Abstract: An ultrasonic cleaning device comprises an ultrasonic pump having a hollow cover forming a spouting port in a narrow portion thereof, an ultrasonic vibrator in a wide portion thereof and a liquid supply port in a side portion thereof. An oscillator is connected to the ultrasonic vibrator. One part of the ultrasonic wave from the vibrator is passed through the spouting portion straight and the other part of the ultrasonic wave is reflected on the inside of the cover and is passed through the spouting port. An object or objects are opposed to the spouting port of the cover.