Abstract: A push button switch assembly comprising a plurality of push button switch actuators includes a flexible, unstretchable electrically non-conductive belt for permitting only one of the push button switch actuators at a time to be in its activated position while the remaining switch actuators are all in their deactivated position. The switch assembly cover includes a molded detent spring for maintaining a switch actuator with a shaft having suitably axially spaced detents in its activated position when one of the detents engages the spring. The switch actuator comprises movable contacts aligned to engage respective stationary contacts disposed in the base of the switch assembly when the switch actuator is in its activated position. The belt is strung over tensioning risers disposed in a predetermined path on the base of the switch assembly at each side of a switch actuator. The switch actuator shaft further includes a groove for confining the belt therein.

Abstract: An ultrasonic cut and seal apparatus comprises a resonator having a removable tip which includes an inclined bore through which a filament is fed to the output surface of the resonator and upon the sheet material to be cut and sealed. The bore accurately guides the filament to the cut and seal region for causing the filament to be fused with the sheet material in the region adjoining the cut. The cutting and sealing is effected by the combination of an anvil exhibiting a cutting surface and at least one tapered sealing surface disposed opposite the output surface of the resonator when the sheet material is fed through the nip between the anvil and the resonant resonator.

Abstract: A method and apparatus for degating individual molded thermoplastic parts from runners use the combination of ultrasonic energy at a predetermined frequency and an anvil plate dimensioned to undergo flexural motion of a substantially large motional amplitude at a frequency less than that of the predetermined ultrasonic frequency for degating the parts from runners.

Abstract: An ultrasonic thickness gauge circuit includes a dual transducer probe and a logic circuit for providing square wave signals whose duration is equal to the time interval between the ultrasonic signal entering a workpiece to be measured and the reception of the ultrasonic signal reflected at the rear surface of the workpiece. When measuring thin wall thicknesses a measuring error arises due to the "V"-shaped transit path of the ultrasonic signals being greater than twice the wall thickness of the workpiece. A low-pass filter and a comparator are provided for modifying the square wave signals to effect correction. The modified signal is then used for providing clock pulses, the quantity of which is a measure of the wall thickness of the workpiece.

Abstract: An ultrasonic seal and cut method and apparatus comprises an ultrasonic sealing and cutting station which includes a horn adapted to be resonant at an ultrasonic frequency and an oppositely disposed anvil having a sealing surface and a cutting surface. As sheet material is passed through the station, the sheet material is cut and sealed in a marginal area adjacent to the cut. A substantially thermoplastic thread, either monofilament or multifilament, is fed together with the sheet material through the station in a position to cause the thread to fuse with the material in the marginal area. The provision of the thread permits the ultrasonic seal and cut method to be used for sheet material having a relatively low thermoplastic fiber content or exhibiting an open mesh weave, or being made of natural fibers.

Abstract: An automatic tuning circuit is provided for adjusting the frequency and phase of an oscillatory circuit in a power supply used for providing high frequency electrical energy to an electroacoustic converter. The oscillatory circuit includes an electrically variable inductance means in a feedback loop coupled between the output and an input of the oscillatory circuit and a switching device. The phase relationship of a signal indicative of the voltage across the switching device and a signal indicative of the state of the switching device and hence the current through the switching device is monitored. The inductance of the variable inductance means is adjusted responsive to the phase relationship of the signals indicative of voltage and current through the switching device for maintaining the two signals in phase during operation of the oscillatory circuit.

Abstract: An ultrasonic welding apparatus for providing a closure on plastic film bags wherein the end of the film bags is gathered, twisted or not twisted, and then welded to provide a hermetic seal, includes an anvil having a recess into which the gathered plastic material is placed for welding. The side of the recess is lined with low friction material, such as nylon or Teflon, to accomodate a sliding fit between the resonator and the anvil recess. Absent a close fit between the anvil side surface and the resonator side surface, bag material will escape into such space, thereby preventing a hermetic seal. The low friction material prevents destruction of the opposing surfaces subjected to high intensity vibrational forces.

Abstract: A resonant sensing device for measuring the hardness of a workpiece to be tested includes a diamond tipped rod adapted to be resonant and for determining the hardness of a workpiece to be tested is brought into forced contact with such workpiece. The difference in resonant frequency of the rod between its not-constrained condition and its constrained condition (forced contact) is a measure of the hardness of the workpiece. The present invention describes a circuit wherein during a first time interval an up/down counter accumulates the counts arising from the oscillations of the not-constrained rod. During the ensuing interval of the same duration, the counter counts down the accumulated count responsive to the oscillations of the constrained rod.

Abstract: The invention relates to a method for testing fuel element tubes by ultrasonic energy. For testing, each tube becomes disposed in the space between a transmit transducer and a receive transducer. The echo signals falling within a predetermined time interval are evaluated. Since the distance between the transducers may vary as the transducers move through the space between fuel element tubes, the transmitted signal reaching the receive transducer without passing through the tube may be confused with the revolving echo signal. Therefore, this invention discloses an arrangement for cyclically controlling the setting of the time gate before each such tube is in position between the transducers. To this end, the ultrasonic transit time of signals between the transmit transducer and the receive transducer is measured in the gap between the last tested tube and the next to be tested tube.

Abstract: The invention relates to an ultrasonic test instrument, in which a receiver amplifier is controlled in dependence upon time by means of a depth compensation signal or else the ultrasonic signal amplified independently of the depth is evaluated by means of a time-dependent variable threshold signal. The depth compensation signals and the time-dependent threshold signals are derived from the same digital signal values stored in a main memory. The test instrument comprises a microprocessor by means of which the digital signal values for each material requiring testing are automatically measured by the instrument itself in conjunction with whichever test probe is used provided a corresponding test block of this material is available.

Abstract: An improved vapor degreaser apparatus includes means for selectively disposing a desiccator assembly within a conventional water separator for drying and removing excess water from a solvent.

Abstract: A circuit for adjusting the sweep time provided by a sweep generator used in an ultrasonic test instrument is described. The adjustment takes into account three test parameters, i.e. the angle of propagation of the sound in the workpiece, the speed of propagation of sound in the workpiece, and the thickness of the workpiece. To this end, the quartz-stabilized frequency of an oscillator comprising an adjustable frequency divider is divided by the angle function value of the angle of sound propagation to which the test instrument is set. The divided frequency is fed to a frequency multiplier in a phase locked loop circuit, comprising an adjustable frequency divider by means of which the speed of propagation of the sound is adjusted. A succeeding time reference stage contains also an adjustable frequency divider by means of which the workpiece thickness is adjusted.

Abstract: This invention relates to ultrasonic test instruments using wide-band test probes of different nominal frequencies fo and discloses an arrangement wherein each wide-band test probe of different nominal frequency fo is coupled in circuit with a receiving amplifier having a frequency response V(f). The frequency response of the receiving amplifier is so selected that the product H(f) comprising the spectral distribution S(f) of the transmitter and the frequency response V(f) of the receiving amplifier is substantially constant approximately up the the nominal frequency fo of the test probe and has its maximum value in that range. For the transmitters conventionally used in ultrasonic test instruments, in which the transmission pulse is generated by a capacitor discharge, the frequency response V(f) of the receiving amplifier should have a linear rise of 6 dB/octave up to approximately the frequency fo.

Abstract: The invention concerns an ultrasonic test probe for use in connection with testing workpieces wherein the angle of propagation of the ultrasonic search beam is adjustable. The probe comprises a linear array of ultrasonic transducer elements and a plastic wedge. An acoustic lens disposed between the array and the wedge causes the individual ultrasonic beams to come to a focus at an acoustic energy exit aperture of the probe. The angle adjustment of the ultrasonic beams is accomplished by energizing in-phase a respective group of transducer elements forming the array.

Abstract: A programmable ultrasonic thickness and acoustic velocity measuring instrument is provided which includes automatic zeroing (calibrating) means, automatic temperature compensation and high temperature warning means, automatic probe identification means, means for automatically correcting the measurement readings for probe characteristics, means for storing and displaying of the minimum wall thickness during a predetermined time interval, and means for providing a display indicative of the difference between a measured thickness and a preprogrammed value.

Abstract: An ultrasonic test instrument includes a pulse generator, a receiver, a cathode ray tube screen display and a time gate means providing a gated time interval for viewing only echo signals which arise from a predetermined workpiece region under test. The time gated interval is shown as a horizontal gate bar display on the screen and the length of the bar being indicative of the gated time interval. Circuitry provided generates a reference signal to cause the gate bar to appear at a height commensurate with the echo signal received in the gated intervals having the highest peak amplitude. Unless reset, the amplitude of the gate bar remains at this peak value although subsequent echo signals may have a lower amplitude.

Abstract: A method for sealing the neck of a thermoplastic container to a thermoplastic cap superposed upon the neck and the cap having a lateral edge extending beyond the periphery of the neck using an ultrasonic welding apparatus includes an ultrasonic resonator having a domical internal cavity in its output end for reshaping the lateral edge of the cap in order to form a peripheral bead along the interface between the cap and the neck of the container.

Abstract: An ultrasonic test probe comprises a transducer and an electrical circuit, particularly means for generating the high voltage transmit pulse to the transducer, all disposed within the probe housing. The high voltage transmit pulse is produced by current flow through an electrical inductor. Other circuit components are also arranged within the probe housing.

Abstract: In an apparatus for receiving ultrasonic waves by optical means a laser beam illuminates a workpiece surface at which ultrasonic waves are manifest in the form of cyclically occurring surface deformations. The reflected light is transmitted to an optical interferometer as a measuring light beam and the beam exiting from the interferometer is converted to an electrical signal and amplified to provide a measuring beam responsive electrical signal. A portion of the laser beam immediately before being incident on the workpiece surface is also passed through the interferometer as a comparison beam. The exiting comparison beam light is converted to an electrical signal, amplified and time delayed to provide a comparison beam responsive electrical signal. By means of a subtracting circuit the comparison beam responsive electrical signal is subtracted from the measuring beam responsive electrical signal to provide a difference signal which is evaluated.

Abstract: A flexible cover, blind or shade is fabricated from thermoplastic rod or tubular members which are spaced from another on a support. The free-standing side is engaged by an ultrasonic resonator to bond the members to one another. The pressure exerted during bonding is of such magnitude as to compress and flatten the members to cause a thin web joining juxtaposed members, the web forming a flexible joint.