Abstract: A drive device of a vibration actuator to cause stable driving of a vibration actuator without causing the occurrence of a cogging phenomenon. In a drive device of a vibration actuator using mechanical vibrating motion of an electromechanical energy converting element which converts electrical energy into mechanical energy, the drive device includes a control circuit to output a control signal of a frequency to drive the electromechanical conversion element, a drive circuit to impress on the electromechanical conversion element an alternating voltage of the same frequency as the drive signal, and a direct current power supply to supply electric power to the drive circuit. The drive circuit has an inductive element connected in series or in parallel with the electromechanical conversion element, and a switching element to open and close at the same frequency as the control signal, connected such that the voltage of the direct current power supply is impressed thereon.

Abstract: A drive device for a vibration actuator which stably drives the vibration actuator and prevents the occurrence of the cogging phenomenon. The vibration actuator provides a drive force by supplying a voltage to an electromechanical energy converting element which converts electrical energy into mechanical energy to produce mechanical vibratory motion. The drive device for the vibration actuator includes a voltage generating device to generate an alternating voltage which is impressed on the electromechanical energy converting element, and a voltage control device to control the alternating voltage of the voltage generating device such that the current supplied to the electromechanical energy converting element from the voltage generating device becomes constant. The voltage control device changes the output voltage value of the voltage generating device according to the excitation state of the electromechanical conversion element.

Abstract: A pulse action facial massager apparatus including a headset assembly for mounting to a user's head. A pair of flexible extension fingers extending from opposite sides of the headset assembly each of which is operably coupled to a vibrating device each generating an independent vibrating action. A tip portion of each extension finger is manually movable for selected contact at independent portions of the user's head. Hence, the respective vibrating device transmits the vibrating action thereof along the extension finger to the respective tip portion. Each vibrating device includes a motor that is controlled by an electronic controller mounted on the headset assembly. The controller permits user-variation of the repetition rate and duty cycle of the motors. This permits the user to vary the vibrational patterns produced by the present invention. In an automatic mode, duty cycle is automatically varied by a sawtooth waveform to produce a dynamically changing pattern of massage intensity.

Abstract: The invention provides a method of operating a dental scalar system having a vibrating scaling tip by continuously monitoring the amplitude and frequency of vibration of the tip which provides scaling power to a tooth in a patient's mouth. The amplitude and frequency of vibration of the tip is continuously adjusted to maintain a substantially constant scaling power. Preferably, the insert is vibrated at its resonant frequency and the system provides a substantially constant tip motion while the user varies the applied pressure between the tip and the tooth.

Abstract: A vibration motor comprising a stator and a rotor together with excitation means for deforming said stator in a vibratory mode enabling it to rotate the rotor, the motor being characterized in that the stator and/or the rotor include(s) a shape memory alloy in the vicinity of or at a zone of mutual contact between the rotor and the stator.

Abstract: A powered surgical tool includes a motor, a motor control module for controlling the actuation of the motor, and a trigger assembly for allowing the user to enter user-selected commands indicative of desired motor rotation. The trigger assembly includes a number of moving magnets located adjacent the sealed housing that contains the circuitry forming the motor control module. There are a set of magnetic field sensors in the motor control module housing. As the magnets are displaced in response to the user's actuation of the switches, the sensors generate signals representative of the user-selected motor commands. The motor control module further includes a motor control circuit and a direction controller circuit that allow the motor to be driven in either forward, reverse or oscillatory rotation.

Abstract: A drive device for a vibration motor which provides constant efficient driving with a simple circuit and control sequence. The drive device for the vibration motor includes a charging circuit which impresses a predetermined voltage on an electromechanical energy conversion element, a discharge circuit which causes discharge of the electromechanical energy conversion element via an inductive element, a control circuit which alternately connects the charging circuit or the discharge circuit to the electromechanical energy conversion element, and a period detection circuit which detects the period of the resonant frequency of a circuit formed by the electromechanical energy conversion element and the inductive element.

Abstract: Piezoelectric actuators bonded on S-shaped brackets extending between a support and a payload, improve vibration isolation therebetween by attenuating resonant vibrations under computer dynamic control relying on predetermined dynamic resonant characteristics and H-Infinity control methods. The system can also be used for pointing the attitude of a payload on a supporting platform. Bonded piezoelectric ceramic actuators bend aluminum portions of the brackets to adjust the attitude and position of the payload respecting the support well suited for improved optical communications, observation and telemetry. The system is enables concurrent vibration isolation and directional control.

Abstract: A method and apparatus for controlling the oscillatory motion of a test device by using amplitude and DC offset feedback for control purposes. The force applied to the test device is monitored by a load sensor and compared to a preset desired amplitude load setpoint to determine the positive peak amplitude of a sinusoidal control signal. The DC offset feedback is monitored by sampling the value of a displacement feedback signal a number of times for each cycle of movement. The values of the samples are averaged to determine a calculated DC offset. The calculated DC offset is compared to a desired DC offset, which is determined from a preset desired displacement setpoint. The difference between the calculated DC offset and the desired DC offset is then used to control the load applied to the test device to maintain the desired oscillatory movement.

Abstract: A rocking motor comprises a coil wound around a hollow coil bobbin. A rotor is rotatably mounted at a position close to an end portion of the coil bobbin. The rotor has a center shaft and a permanent magnet and is magnetized with two poles such that the positions of the poles are located close to the coil and the magnetization angle is greater than 90 degrees but less than 180 degrees. The positions of the poles of the rotor and the coil are adjacent to one another so that a rotary torque can be efficiently obtained by a magnetic force generated by the coil. The rocking motor can generate a high power output with a relatively low power supply and its operational performance is not adversely affected by an external magnetic field.

Abstract: A reaction force generating apparatus is provided which generates a reaction force for a rotationally operated member to be manually or mechanically operated. An alternating motor is provided that has a stator with three-phase coils; a rotor including permanent magnets; and a rotational axle extending from the center of the rotor and having a rotationally operated member attached to its one end. A direct voltage is supplied to the three-phase coils of the alternating motor, thereby producing a magnetic field on the stator. The magnetic field is oriented in one direction and cooperates with the permanent magnets to generate an electromagnetic attraction force for maintaining the operated member in a predetermined angular position. When the operated member is moved, a torque, or reaction force, is generated to restore the initial position of the operated member.

Abstract: A power supply for vibrating compressors comprises a voltage booster circuit portion having voltage changing means for boosting the DC voltage of a commercially available battery and changing the boosted voltage, and an AC voltage generating circuit portion for supplying the boosted DC voltage to the vibrating compressor. The AC voltage generating circuit portion comprises a MOSFET or bipolar transistor for driving a vibrating compressor, a timer IC for generating pulses to cause the MOSFET or bipolar transistor to switch, a forced operation circuit for detecting a timing at which a counter electromotive force generated by the vibrating compressor during the OFF period of the MOSFET or bipolar transistor is recovered to the neighborhood of 0 volts and forcibly reversing the output of the timer IC, and a driver for driving the MOSFET based on the output of the timer IC or a base-current supply circuit for controlling the bipolar transistor.

Abstract: The present invention relates to a method for driving an ultrasonic motor of the type which includes a vibrator for causing a flexural vibration wave in response to a pair of AC driving voltage signals, and a rotor in contact with the vibrator and moved by the flexural vibration wave. The rotational speed of the ultrasonic motor is controlled by using a feedback signal and a data table, the feedback signal indicating the current rotational speed of the ultrasonic motor, and the data table storing values of the feedback signal as a standard function of the rotational 21 speed. The method includes the step of sampling the feedback signal and detecting the rotational speed in a plurality of rotation states of the ultrasonic motor. The method obtains an approximate function representing the relationship between the sampled feedback signal and the detected rotational speed of the ultrasonic motor, and calculates correction coefficients for adjusting the approximate function to the standard function.

Abstract: A fingertip massager transmits a pulsating action through the fingertips of the user to an area being massaged. Vibrating pulsators are attached to the user's fingers for vibrating same. A controller attached to the user's wrist controls the vibration of the vibrating pulsators, including the vibration rate. Flexible connection tubes connect the controller and the vibrating pulsators. The pulsating circuit includes variable square wave circuitry for producing dual alternating voltage outputs and pulsating circuitry for producing a vibrating motion.

Abstract: An adaptive process control system selectively controls vibrations in a given medium in real time. Unwanted vibrations present at a point being monitored in a given medium are sensed, and the system generates an appropriate offsetting vibration that is applied to the medium at a convenient location, which may be remote from the monitored point. The system includes a vibration sensor, such as one or more accelerometers, that sense both input and output vibrations present within the medium; at least one vibration generator, such as an electromagnetic shaker, that generates appropriate offsetting vibrations that are applied to the medium at one or more appropriate locations; and a neural network controller that controls the vibration generator(s) so as to force the sensed vibration at the monitored point(s) to a desired level. The adaptive vibration cancellation provided by the invention takes place in real time, and without the need to process time-consuming complex mathematical algorithms.

Abstract: A control system for mixing materials in a container. A screw-driven pressure plate clamps the container during mixing. Current of the clamping motor driving the screws is monitored and control circuitry allows multiple speed, multiple current draw, automatic switch-over operation of the clamping motor. Circuit components are automatically checked, and control over a mixing or clamping operation is assumed if necessary.

Abstract: An arrangement is provided for removing foreign substances from a mirror. A vibrator for vibrating the mirror includes a vibration controlling unit for supplying power to the vibrator. As the vibration controlling unit is located close to the vibrator, the length of the conductive wire which transmits the power can be minimized so as to reduce radio noise. The heat generated by the vibration control unit can be radiated sufficiently through a metallic case member and the vibration controlling unit can be disposed in the closed, small space between the mirror and the housing. Therefore, the size of the housing can be reduced so as to minimize the space which surrounds the vibration control unit. Further, the vibration control unit can be protected from contamination due to the closed case member.

Abstract: The present invention relates to a vibration wave motor of the type in which an electro-mechanical energy conversion element is disposed on a vibration member and a frequency voltage is applied to the element to form a travelling vibration wave on the vibration member and a moving member is driven by the vibration wave. In the present invention, when the motor has assumed a resonance or the vicinity thereof when speed adjustment is being effected with the frequency of the periodic voltage changed, the change of the frequency to any frequency exceeding the then frequency is inhibited so that the drive frequency is not changed to a value exceeding the resonance frequency.

Abstract: A converter has a body housing a rotatable shaft constituting a drive on which an eccentric weight such as a ferrous metal ball is carried. An end is connected at one end to the shaft while its opposite arm supports the weight in fixed relationship to the shaft so that the weight travels concentrically as the shaft turns. Bearings rotatably mount the ends of the shaft to the housing body cavity defined by outer sidewalls supporting at least four spaced-apart electromagnets. The electromagnets are spaced radially about the drive shaft so as to permit the arm and weight to rotate about the turning axis in response to electrical energization of the electromagnets in a predetermined sequence. The magnetic flux pulls and pushes the weight along its circular travel path.

Abstract: A drive circuit including a power stage [PSH/PSV] and a control stage therefor to co-operate to supply energy in a controlled manner with regard to a reference value to an inductive load when connected in operation, means [R21, R41/R25, R42] in the power stage to produce a lower level signal indicative of the energization of the load, means [HPR/VPR] to generate a reference value for the energization signal representing a required energization, means [U3.3/U3.4] to compare the energization signal and the reference value and generate an error signal representing any difference therebetween and means [U2.1/U2.3, U2.4] to apply said error signal to said control stage to alter the energy supplied to the load towards the required condition, the reference value may also be related to the frequency at which the load is energized (SE, FBF, OSC, D4).

Abstract: Disclosed is a motor having a rotor driven by a vibrator generating a vibration of rope skipping motion. The rotor has a friction portion which is in contact with the friction portion of the vibrator so as to be given the vibration of rope skipping motion by the friction portion of the vibrator, and a supporting portion which is provided at a position spaced apart from the friction portion and which is in contact with a portion of the vibrator. Thus, the motor is constructed compactly.

Abstract: A circuit for driving an ultrasonic motor which is driven by being applied with multi-phase alternating voltages comprises: a digital oscillator for providing a signal having a frequency higher than that of said alternating voltages; a frequency divider for dividing the frequency of the output signal of the digital oscillator into a desired frequency to provide a basic clock signal; a plurality of presetting circuits, each of independently presetting a delay time for generating a plurality of delay clocks which are delayed with respect the basic clock by different delay times; a plurality of delay circuits, each connected with a respective one of the delay time presetting means for generating a plurality of different delayed clock which are delay with respect to said basic clock by different periods of delay time in accordance with the preset delay time; and voltage generators which generates multi-phase alternating voltages from the basic clock and plurality of the delayed clocks for applying the multi-phase

Abstract: An apparatus for cancellation of vibrations in a device. A first matrix (51) combines the vibration signals from a plurality of locations to produce mode signals indicative of individual modes of vibration of said device. An adaptive element in response to said mode signals generates mode vibration attenuation signals corresponding to said mode signals. A second matrix (56) combines the mode vibration attenuation signals to produce vibration attenuation signals for generating vibration attenuation forces.

Abstract: The apparatus includes a driver (86). The driver (86) includes a front portion (90) which is adapted to receive a riveting die (92), and a rear portion (88) which is a copper plate. The copper plate (88) is receptive to the establishment of magnetic field currents therein. The actuator further includes a coil (72) which is positionable in close proximity to the copper plate (88) of the driver (86). The apparatus further includes a bank of capacitors having a stored charge so as to produce a current pulse through the coil (72) when the capacitors are connected to the coil (72). Still further, the apparatus includes a control means for selectively connecting the stored charge from the capacitors to the coil. The copper plate (88) is relatively thick compared to that used in high voltage electromagnetic actuators, such that the present apparatus requires only a relatively low voltage in order to produce the required high forces to accomplish the desired riveting.

Abstract: A flat brushless motor utilizable as a warning means in a portable communication device such as a pocket bell. The flat brushless motor is such that the center of gravity of the back-yoke (5a) is displaced from the center of rotation so that, by the rotation of the unbalanced back-yoke (5a), vibrations can be generated and, by the elimination of a weight or the like for generating the vibrations, the manufacture in a flat and compact size as well as the reduction in number of component parts can be attained.

Abstract: A combination vibration generator and dampener having magnetic suspension and servo-control along three axes includes a hollow outer body fixed to a structure whose vibration is to be controlled, and an inner body which is essentially spherical in shape and which is inside the hollow outer body. Six active magnetic bearing elements are diametrically disposed in pairs along three orthogonal axes and serve to hold the inner spherical body inside the hollow outer body without direct contact between the inner and outer body. At least three position detectors detect the position of the inner body relative to the hollow outer body while at least one vibration detector device detects vibration forces on the structure whose vibration is to be controlled.

Abstract: A structural magnetic vibration controller and a method for actively controlling vibrations through the use of a magnetic coupling between a damper mass and a stationary component of rotary machinery wherein the stiffness and damping characteristics of the magnetic coupling are controlled as a function of the relative movements between a first electromagnet carried by the machinery and a second electromagnet carried by the damping mass.

Abstract: The electrical termination impedance of a variable reluctance electro-mechanical transducer is changed automatically in response to the frequency of vibration applied to the transducer, to provide the optimum electrical termination impedance which produces the highest effective mechanical impedance at said frequency. The transducer includes magnetic cores interconnected by a spring formed by cutting a relatively thin medial annulus in a relatively thick flat disk. A digital logic circuit uses a signal counter and NAND gates to determine the frequency and close the appropriate fast-acting relay in a parallel array of capacitor-relays. A negative-impedance electrical termination provides a high mechanical impedance over a broad band of frequencies. A shunting circuit eliminates spurious resonances by providing substantially no shunting in the transducer-terminating circuit at resonant frequency, and substantial shunting in the terminating circuit at other frequencies.

Abstract: The apparatus includes a driver (86). The driver (86) includes a front portion (90) which is adapted to receive a riveting die (92), and a rear portion (88) which is a copper plate. The copper plate (88) is receptive to the establishment of magnetic field currents therein. The actuator further includes a coil (72) which is positionable in close proximity to the copper plate (88) of the drive (86). The apparatus further includes a bank of capacitors having a stored charge so as to produce a current pulse through the coil (72) when the capacitors are connected to the coil (72). Still further, the apparatus includes a control means for selectively connecting the stored charge from the capacitors to the coil. The copper plate (88) is relatively thick compared to that used in high voltage electromagnetic actuators, such that the present apparatus requires only a relatively low voltage in order to produce the required high forces to accomplish the desired riveting.

Abstract: A system for shaking water off a surface includes an electromagnetically operable driver unit for driving a member having the surface. The driver unit is connected to a control unit which controls oscillation frequency to be generated by the driver unit. The control unit adjusts the frequency of oscillation transmitted to the member for matching the oscillation frequency with the resonating frequency of the member for effectively shaking the water off the surface.

Abstract: A circuit for phase control of an AC-DC motor for a machine operated in defined (preferably two) load conditions with a controllable current flow control valve located in series with the motor and associated triggering pulse stage. The circuit includes a measuring circuit designed as a rectifier circuit with filter link for detection of the load current flowing through the load path of the current flow controller or through the motor as well as a threshold value circuit which determines a first basic desired value of the triggering voltage level at the triggering pulse stage at low load current values (idling). If a triggering threshold, adjustable at the triggering value circuit, is exceeded, then the triggering voltage level is switched over onto a second firmly or permanently adjusted value, so that the motor now operates at nominal load with nominal rpm through the current flow control valve, now controlled to be fully advanced.

Abstract: An arrangement to controllably vibrate a resiliently supported body including electromagnetic drive means energizable to vibrate the body, means to control the device means, means to detect the actual vibration of the body, the control means including digital signal processing means to produce a control pulse train representing a required phased difference from the detected vibration to control the energization of the drive means with an independently set phase difference from the detected frequency to sustain the vibration of the body.

Abstract: The electrical termination impedance of a variable reluctance electro-mechanical transducer is changed automatically in response to the frequency of vibration applied to the transducer to provide the optimum electrical termination impedance which produces the highest effective mechanical impedance at said frequency. The transducer includes magnetic cores interconnected by a spring formed by cutting a relatively thin medial annulus in a relatively thick flat disk. A digital logic circuit uses a signal counter and NAND gates to determine the frequency and close the appropriate fast-acting relay in a parallel array of capacitor-relays. A negative-impedance electrical termination provides a high mechanical impedance over a broad band of frequencies. A shunting circuit eliminates spurious resonances by providing substantially no shunting in the transducer terminating circuit at resonant frequency and substantial shunting in the terminating circuit at other frequencies.

Abstract: Mechanical resonance of the vibratory feeder is maintained by minimizing a phase angle difference between substantially sinusoidal drive voltage and current wave forms. The mass flow rate of material being fed is controlled by controlling the electrical power applied to the vibratory feeder compared with a desired electrical power computed from a desired flow rate. The preferred embodiment includes synthesized drive wave forms which are variable in frequency and amplitude in order to maintain the vibratory feeder in mechanical resonance at the desired flow rate. Resonant operation and accurate material flow are accomplished without use of electromechanical vibration sensors and control is accomplished using the magnitude and phase relationships between the applied voltage and current drive wave forms.

Abstract: A motor-compressor comprising a vibration motor (1) having a rotationally vibrating drive shaft (4) and a compressor (2) having at least one piston (10) which is linearly reciprocated by the motor shaft (4) is suspended in the housing (14) by means of springs (15) so that the points of attachment (17) of the springs are coplanar with and as close as possible to the axis (16) of the rotation, to which the motor- compressor is subjected in operation. This counteracts the imbalance forces to a maximum extent and minimizes the dynamic forces on the housing.

Abstract: Disclosure is made of an electromagnetic vibrator comprising a housing (1) having a cover (6), which accommodates a striker (2) and an excitation coil (3) producing an alternating magnetic field which makes the striker (2) reciprocate along the geometrical axis of the excitation coil (3), the striker (2) being arranged freely in the housing (1) and comprising a permanent magnet (4) having an end surface in a plane parallel to a base (5) of the excitation coil (3) which is located, when the magnetic field of the excitation coil (3) and the magnetic field of the permanent magnet (4) are interacting, at a distance from the base (5) of the excitation coil (3), which is equal to 0.6-0.7 of the height of the excitation coil (3).

Abstract: A vibrator for providing revolving vibration to a body to be vibrated such as a dispersion table of a vibration feeder or a sieve stack of a screening machine. In this vibrator, it is possible not only to control the amplitude of vibration but also to obtain a uniform vibration amplitude everywhere in the vibrating body inclusive of its center. A unique feature of this vibrator involves a plurality of armatures fixed to and around a vibrating member and actuated by associated electromagnets energized with multiphase a.c. power.

Abstract: A load support servomechanism circuit controls the armature of a shaker apparatus. The circuit includes a position sensor, peak detectors connected to outputs of the position sensor, an A/D converter connected to outputs of the peak detectors through a switching bank, a power supply and a microprocessor which provides clock, read, write and ready signals and which automatically controls the position of the armature through solenoids operating on an exhaust valve and a pressure valve. Manual operation of the shaker armature is also provided.

Abstract: Vibration isolation between a source (1) and a mounting (3) is provided by means of a vibration-cancelling actuator (4a) with a shear isolator (5) placed in series with the source (1). Mechanical and magnetic actuators are disclosed, a preferred mechanical actuator including its own shear isolation with a ratio of compliance in shear and axial directions of at least 50:1.

Abstract: An electromagnet hammer of the type described in U.S. Pat. No. 4,215,297 is autosynchronized by triggering the discharge thyristor in response to the detection of the position of the armature by a proximity detector, or by direct detection of the zero passage of the negative amplitude of the discharge current, or at a reference point representing the position of the armature, with a delay equal to at least half the period of the natural period of oscillation of the armature/plunger and its elastic suspension.

Abstract: A control arrangement for vibratory conveyors, including bowl and linear types, in which the vibration frequency is set by the behavior of the conveyor and not by an applied frequency. A sensor, SC, senses the behavior of the conveyor and a frequency, of controlled amplitude and phase, is derived from the sensor output to energize conveyor drive means, AV and AH1 to AH3. User controls (HA, VA, PA) for amplitude and phase can be mark/space adjusters (HMS, VMS, DMS) effective on the base circuits of transistors connected to electromagnetic actuators. Low voltage operation (less than 50v) is provided without proportionally increased current, partly by energy recovery from the inductors in the actuators. Two levels of protection against supply ripple are included (RT, RLA) and the actuator drive can be stabilized against supply variation (MSC). The low-voltage operation provided is both safer and more efficient than mains voltage operation.

Abstract: A blocking oscillator for a reciprocating electromagnetic actuator having a solenoid coil, a detection coil for generating a control signal in response to a charge in the magnetic field generated by the solenoid coil, a silicon Darlington amplifier responsive to the control signal to control the current through said solenoid coil, and a diode connected in series with the collector of the Darlington amplifier rendering the Darlington amplifier immune to reverse voltage and transient signals.

Abstract: A vibrating armature motor, which includes a voltage source, an armature, an electromagnet having at least one exciter coil disposed adjacent the armature, a spring for rotationally biasing the armature, a sensor element for sensing the rotational velocity of the armature and for generating a signal proportional to the sensed velocity, a variable duty cycle pulse generator for generating a stream of triggering pulses, the duty cycle of the triggering pulses being dependent upon the sensor signal, and an electronic switch for controlling the current flow from the voltage source through the exciter coil in response to the triggering pulses.

Abstract: A control arrangement for vibratory conveyors, including bowl and linear types, in which the vibration frequency is set by the behavior of the conveyor and not by an applied frequency. A sensor, SC, senses the behavior of the conveyor and a frequency, of controlled amplitude and phase, is derived from the sensor output to energize conveyor drive means, AV and AH1 to AH3. User controls (HA, VA, PA) for amplitude and phase can be mark/space adjusters (HMS, VMS, DMS) effective on the base circuits of transistors connected to electromagnetic actuators. Low voltage operation (less than 50v) is provided without proportionally increased current, partly by energy recovery from the inductors in the actuators. Two levels of protection against supply ripple are included (RT, RLA) and the actuator drive can be stabilized against supply variation (MSC). The low-voltage operation provided is both safer and more efficient than mains voltage operation.

Abstract: Circuitry is disclosed for driving the transducer assembly of a dental handpiece at its resonant frequency. The circuitry includes a variable frequency oscillator and a peak-detecting processor which allows the oscillator to sweep through a continuum of frequencies until maximum current in the transducer driving coil is sensed.

Abstract: A method of, and apparatus for, energizing electromagnetic vibrators. An electromagnetic vibrator, driven by an electromagnet, is energized directly from an electric mains supply line carrying alternating current at a particular frequency. The electromagnet is operated at a fraction greater than one-quarter, and preferably equal to two-thirds or two-fifths, of the supply frequency such that the current drawn from the mains supply is substantially alternating current.

Abstract: A control system is disclosed for use with a device, such as a vibratory bowl feeder, having a bowl or other member mounted for vibratory motion and including an electromagnetic driver for vibratorily driving the part. The control system includes a detector for detecting the vibratory frequency of the part, which tends to vibrate at its resonant frequency, and causes energizing pulses of power to be supplied to the driver supplied at a frequency equal to the detected frequency. Thus, the driving frequency is made equal to the resonant frequency and follows changes in such frequency to obtain maximum performance. The power to the drivers is also switched so that during alternate pulses the current flows through the driver coil in opposite directions to inhibit buildup of residual magnetism in the coil core. The control system uses a phase-locked loop circuit and other parts comprised of components most of which are available as standard integrated circuits.

Abstract: Apparatus for continuously feeding selected ratios of materials to be mixed together. Accurate proportioning of the component materials is facilitated through the advantages of the invention. Since all ingredients are introduced continuously in the selected ratios, overrun problems are resolved and the exact amount of the mix required can be produced. Dry particulate materials in granular, pellet or powdered form and also liquid components of a mixture are contemplated by the invention. Thus the inventive device accomplishes the precise control of the blending of dry granular, slurry and liquid components on a continuous feed basis. The invention achieves this result through the maintenance of precise voltage ratios rather than voltage levels. Applicability is to vibrators delivering dry materials, augers delivering dry and/or slurry materials and also to pumps delivering liquid materials.

Abstract: A vibrator mechanism, including a transducer and driving circuit, particularly adapted to vibrating a waterbed, includes two independently controlled vibration sources, each of which can generate vibration of varying amplitude and frequency. These two sources are typically mounted at opposite ends of a waterbed frame and vibrated at different frequencies so that interference waves may be produced within the water of the bed to produce a pleasing effect for the user. Additional circuitry is described which provides a time varying frequency and amplitude for each of the vibrators, and this circuitry is in turn controlled by a clock circuit so that, by using the time varying frequency and amplitude, the user may be slowly lulled to sleep or slowly awakened using the vibration within the waterbed as a stimulus for controlling the rate of falling asleep and waking up.

Abstract: A vibrator motor is coupled to the frame of a body support structure to vibrate the latter. The motor is energized by a train of triangular pulses modulated by a triangular pulse signal having a lower frequency than that of the triangular pulse train.