Abstract: An apparatus for sensing the acoustic energy responsive deformation of a workpiece surface by optical means, that is without physical contact with the workpiece surface, comprises the use of a laser light beam illuminating the workpiece surface portion along which the acoustic energy responsive deformation is manifest. The laser light incident upon the workpiece surface is reflected at the workpiece surface and, modulated responsive to the surface deflection, is transmitted to an optical phase interferometer and to a photoelectric means associated therewith. The output from the photoelectric means is transmitted to an evaluation unit. The improvement shown in this invention concerns means for maintaining the reflected light intensity at a predetermined level by comparing the reflected light intensity with a preset level and feeding a control signal to a light control means controlling the laser light intensity incident upon the workpiece surface.

Abstract: Laser light for producing acoustic waves in a specimen to be examined is carried to the specimen from a single laser by a plurality of fiber optic cables. The fiber optic cables have different path lengths to cause a specific time delay between adjacent fiber optic cables to focus and steer the sonic waves in a desired direction.

Abstract: An apparatus for maintaining the adjustment of coincidence and relative phase relationship of light beams in an optical interferometer comprises the passing of a measuring light beam and of a control beam through substantially the same paths of the interferometer. Any change in optical alignment of interferometer components from a set condition is manifest as a change of the electrical signal produced by photoelectric sensing means which receive the control beam. The change of the electrical signal is processed by an electrical circuit and fed to one or more positioning means supporting an optical component of the interferometer for causing a repositioning of such component to thereby restore the set condition. In a typical embodiment, the component is a reflective surface mounted on a set of piezoelectric positioning means.

Abstract: A method of friction welding thermoplastic materials, such as a reinforcing plate to the inner surfaces of oppositely disposed legs of a generally U-shaped workpiece, wherein a flexible force applying means applies a force in a direction normal to the direction of relative motion between the parts but in the plane of the mating surfaces for urging the legs of the U-channel into intimate contact with the edges of the reinforcing plate. During a weld time interval the parts undergo relative linear reciprocating motion while being urged in intimate contact by the flexible force applying means which causes the mating surfaces to soften under the influence of friction. After the weld interval, the parts are returned to their original position and are held in forced contact for a time sufficient for the mating surfaces to solidify. Upon solidification the force ceases and the welded parts are removed from the apparatus.

Abstract: The results of the non-destructive testing of objects with a beam of ultrasonic energy is enhanced by generating display control signals commensurate with a precisely defined region in the test object. These region related signals may be displayed as a "gate" bar on the screen of a cathode ray tube simultaneously with the display of echo related signals. Echo related signals having a magnitude greater than a threshold level, as also defined by the "gate" bar, are detected and may be employed to energize an alarm.

Abstract: An ultrasonic transducer probe for testing workpieces exhibiting compound surfaces includes a molded plastic body which precisely fits to the shape of such workpiece surfaces. Moreover, the body includes, as an integral part thereof, an indexing portion for accurately locating the transducer probe in relation to a predetermined workpiece test area to cause the transducer element embedded in the molded body to transmit ultrasonic energy in the predetermined test area. The transducer probe is secured to a manipulator for remote operation.

Abstract: A method and apparatus for determining by the pulse-echo method the acoustic velocity of a workpiece of known thickness utilize measurement of the transit time of the first rear wall echo signal and that of the second rear wall echo signal. The two transit times are then processed in a microprocessor which also controls the entire measuring cycle. For accurate measurement the transit time is defined as the time interval from the leading edge of the trigger pulse, which triggers the transmit pulse generator, to the time at which the respective echo signal exceeds a preset threshold amplitude.

Abstract: This invention relates to resonators as used in sonic or ultrasonic apparatus. Particularly with bar type resonators there is manifest a reduction of vibrational amplitude at the output surface from the central area toward the lateral edges. In the present arrangement the input surface is provided with pads to increase the mass ratio between the input and output sections for effecting substantially uniform motional amplitude along the entire output surface.

Abstract: A friction welding apparatus for joining thermoplastic materials, such as a reinforcing plate to the inner surfaces of oppositely disposed legs of a generally U-shaped workpiece, includes flexible force applying means for applying a force in a direction normal to the direction of relative motion between the parts but in the plane of the mating surfaces for urging the legs of the U-channel into intimate contact with the edges of the reinforcing plate. During a weld time interval the parts undergo relative linear reciprocating motion while being urged in intimate contact by the flexible force applying means which causes the mating surfaces to soften under the influence of friction. After the weld interval, the parts are returned to their original position and are held in forced contact for a time sufficient for the mating surfaces to solidify. Upon solidification the force ceases and the welded parts are removed from the apparatus.

Abstract: A method for closing an open end of a thermoplastic tube by applying ultrasonic energy to the end in a direction normal to the longitudinal axis of the tube. A horn adapted to undergo ultrasonic vibrations is provided and includes an open cavity disposed substantially at an antinodal region of longitudinal motion of the horn and oriented normal to the direction of longitudinal motion of the horn. The horn is rendered resonant along its longitudinal axis while the open end concomitantly is urged into the cavity in a direction normal to the direction of longitudinal motion of the horn thereby forming the end to the shape of the cavity.

Abstract: A power measuring arrangement is incorporated in a vibration welder at the area of welding workpieces. The arrangement comprises force and velocity sensing means, each providing respective electrical output signals which are multiplied to provide an output signal of the actual power available at the weld plane.

Abstract: When sensing the presence of ultrasonic energy in a workpiece portion by illuminating such portion with light from a single-mode frequency stabilized laser, the reflected light, frequency modulated by the Doppler effect due to the ultrasonic energy induced deflection of the workpiece portion, is passed through a gas filled light filter. The frequency modulated light is amplitude modulated by the filter by selecting the frequency of the laser to cause a point of operation which is located along a steep slope portion of the absorption curve characteristic of the filter. To increase the steepness of the slope portion of the filter, the present invention discloses the use of laser light to saturate the filter in a part region.

Abstract: Echo related signals, commensurate with the results of the non-destructive testing of an object with a beam of ultrasonic energy, are presented along with or alternately with textual information on the screen of a cathode ray tube. The textual information is derived from data permanently stored in a memory of a computer and combined with variable data also stored in a memory of the computer.

Abstract: Display of the results of non-destructive testing with a beam of ultrasonic energy is enhanced by exercising precise control over the horizontal sweep voltage which is applied to the deflection plates of a cathode ray tube on which the test information is displayed. The sweep voltage generator produces a sawtooth waveform which has a precisely selectable slope. The sawtooth voltage waveform slope may be adjusted by selecting the capacitance, which is charged from an adjustable constant current source, and by varying the charging current. A microprocessor, which stores information commensurate with various waveform slopes, will control the adjustment of the sawtooth waveform slope by comparison of the stored information with keyboard entered data corresponding to a desired slope.

Abstract: A method for securing a thermoplastic part to another part by applying ultrasonic energy to a projection of the thermoplastic part in a direction substantially normal to the longitudinal axis of the projection. The exposed end of the projection is urged into an open cavity disposed in a side wall of a horn adapted to undergo ultrasonic vibrations. The cavity further is disposed substantially at an antinodal region of longitudinal motion of the horn and oriented normal to the direction of longitudinal motion of the horn. The horn is rendered resonant along its longitudinal axis while the exposed end concomitantly is urged into the cavity.

Abstract: An ultrasonic half-wavelength resonator characterized by an input surface and an output surface both being disposed at antinodal regions of the longitudinal vibratory energy travelling through the resonator and a medially disposed nodal region is provided with a plurality of slots disposed in the resonator extending from a region near the input surface to a region near the output surface and passing through the nodal region. The slots being angled relative to the longitudinal axis of the resonator from the input surface to the output surface to provide substantially uniform motion along the output surface of the resonator.

Abstract: An ultrasonic seaming method and apparatus for continuously bonding thermoplastic material are disclosed. A movable anvil is disposed opposite the output end of a horn for providing a gap through which the thermoplastic material is conveyed. The anvil cyclically is moved away from the face of the horn and immediately thereafter is urged under slight adjustable pressure against the underside of the material and then is clamped in position for a predetermined period of time or an amount of material feed.

Abstract: An apparatus for pumping a laser by a source of light comprises a movable housing having a plurality of cavities each containing a respective light source for pumping the laser and a laser contained in a cavity of a stationary housing. The cavity of the stationary housing forms with a respective complementary cavity of the movable housing a cylindrical pumping chamber. Responsive to the failure of a lamp, the movable housing is indexed to bring a new lamp into operative relation with the laser.

Abstract: An ultrasonic thickness measuring apparatus comprises means for developing pulse counts responsive to the transit time of the ultrasonic search signal traversing the workpiece. The accumulated pulse count is displayed after each transit time interval and is used also to derive a correction factor which is inserted into the counter accumulating the counts during each time interval. This arrangement provides for the apparatus to almost immediately display a thickness value which nearly coincides with the final measurement value.