Abstract: For sensing the presence of an ultrasonic wave propagated within a workpiece at the surface of such workpiece, the workpiece surface is illuminated with a laser beam and opto-electric means, such as an interferometer, are used to sense the minute workpiece surface deformation caused by the ultrasonic wave front. In order to sense the ultrasonic waves which are incident upon the workpiece surface at an oblique angle, the workpiece surface is illuminated in a pattern of equidistantly spaced strips. The spacing of the strips is determined by the angle of the ultrasonic wave and the wavelength of the ultrasonic wave. The resulting electrical signals are processed simultaneously or in sequence.

Abstract: A method and apparatus for producing on the surface of a workpiece an ultrasonic pulse wave without physical contact comprise the use of a laser beam illuminating a small, striplike, portion of the workpiece surface and such portion being moved with uniform motion along a linear axis over a predetermined distance. The angle of propagation of the resulting ultrasonic wave is a function of the propagation velocity of sound in the workpiece and the velocity of the illuminated portion along the linear axis.

Abstract: In a pulse echo ultrasonic velocity measuring apparatus timing gate signals corresponding to the transit time of search signals traveling through a workpiece are generated. The quantity of fixed frequency pulses occurring during successive timing gate signals is counted and accumulated using time interval averaging techniques until a predetermined quantity of pulses commensurate with the thickness of the workpieces is accumulated. Concurrently, the quantity of search signals required to accumulate the predetermined quantity of pulses is counted. The quantity of search signals counted is commensurate with the acoustic velocity of the workpiece.

Abstract: A pulse-echo ultrasonic transducer probe includes a substantially centrally disposed axial bore running therethrough and a radial slot extending from the bore to the periphery of its housing. A slotted cap dimensioned to rotatably fit over the top of the housing is provided with a hollow semi-circular stem extending into the bore, the slot of the cap being aligned with the longitudinal opening of the stem. The slot of the cap and that of the transducer, when passing a surgical instrument through the bore into an opaque body, are rotatably adjusted so that they are out of registry with one another for supporting the surgical instrument and for maintaining the instrument in the center of an ultrasonic search beam. Subsequently, after the instrument has reached the desired position in the body the slots are brought into registry for providing removal of the transducer probe from around the instrument.

Abstract: A pulse peak detector circuit for use in measuring the peak amplitude of a fast rise time, narrow pulse width pulse as in commonly encountered in an ultrasonic non-destructive testing instrument includes two amplifying means. A first amplifying means compensates small amplitude signals for the characteristics of a unidirectional current conducting means forming a part of the detector circuit while the second amplifying means provides conventional amplification of the applied signal.

Abstract: A method and apparatus for ultrasonic nondestructive testing of workpieces include automatic compensation of echo responsive electrical signals commensurate with preprogrammed test parameters. The test parameters include at least one of the following: depth dependent correction of the individual DGS (distance, gain, size) values for each respective probe; correction for material related properties of the workpiece and coupling medium; correction for temperature affecting the testing of the workpiece. Preferably, a compensating signal generated commensurate with the sum of the correction signals is used for varying either the gain of a receiver amplifier or a predetermined level provided to a comparator circuit or both. Embodiments disclosed are applicable for processing both analog and digital echo responsive electrical signals.

Abstract: A real-time ultrasonic imaging system includes a display which is compensated for the non-ideal characteristics of the search beam profile. Echo responsive electrical signals are provided to a preprogrammed computing means for being processed to compensate for the characteristics of the test probe. The processed signals are displayed as being in focus at all distances from the probe, thereby resulting in an image exhibiting improved resolution.

Abstract: In order to increase the speed at which a workpiece is tested by the ultrasonic pulse-echo method, the dead time between individual measurement time intervals is shortened by providing a minimum predetermined time interval selected for the specific test conditions. When an echo responsive signal is manifest in the receiving circuit, in order to prevent the occurrence of phantom echo signals arising in the following measuring interval, the generation of the succeeding transmit signal is inhibited for the predetermined time interval after receipt of the last echo responsive electrical signal of the measuring interval having an amplitude exceeding a predetermined minimum amplitude. The test speed therefore, is made adaptive to the condition of the receipt of the number of echo responsive electrical signals exceeding a predetermined minimum amplitude.

Abstract: In an ultrasonic pulse-echo test circuit a probe means is coupled via a liquid filled coupling path to a workpiece which undergoes motion relative to the probe means. For each search signal transmitted by the probe means the transit time of such signal is measured from the time of transmission by the probe means to the receipt of the workpiece rear surface responsive echo signal. A computer coupled to receive the transit time values is programmed to classify transit time changes as fast occurring changes, caused by changes in coupling path length, or as slow occurring changes, caused by workpiece thickness changes. A defect gate forming a part of the test circuit is controlled by adjusting its opening responsive to a change in coupling path length and its closing responsive to a workpiece thickness change.

Abstract: An ultrasonic imaging apparatus is disclosed having a display selectably interchangeable between a shades of gray image presentation and an edge enhanced image presentation to facilitate distance measurements of the image on the display screen. A first filter network processes echo responsive electrical signals for preserving echo amplitude information in a shades of gray image presentation and a second filter network processes the echo responsive electric signals for enhancing only the leading edge of the electrical signals.

Abstract: The time interval between two consecutive pulse signals, as occurring for instance in nondestructive ultrasonic pulse-echo testing, is measured by measuring with a counting frequency the width of the interval start pulse signal and the width of the interval stop pulse signal at respective base lines, and the time interval between both stated signals. Using either two different counting frequencies having a ratio of two to one, or utilizing summing and dividing means the time interval between the start and the stop pulse signals is determined with negligible error.

Abstract: In a pulse-echo ultrasonic circuit an ultrasonic search signal is periodically transmitted into a workpiece. The ensuing pair of echo signals (entrant and rear surface reflection respectively) are fed to a timing circuit for providing a timing signal responsive to the time interval between the two echo signals. A fixed pulse width pulse generator is triggered responsive to the search signal. The output from the fixed pulse width generator and the timing signal from the timing circuit are selectively fed to a converter circuit for providing an output signal indicative of workpiece thickness or workpiece acoustic velocity. The converter circuit includes adjustable parameters comprising current magnitude and resistance to provide suitable calibration. Similar calibration is achieved also by varying the repetition rate of the search signal.

Abstract: This invention relates to immersion ultrasonic pulse-echo testing of tubes or bars for internal defects wherein means are provided to continuously monitor the operation of the test channel. As ultrasonic energy enters the workpiece, the round workpiece surface causes acoustic energy scatter responsive echo signals which are sensed by the transmitter probe, are amplified and applied to a threshold circuit. If the amplitude of the scatter responsive signal falls below a predetermined level, an output signal indicative of "loss of operation" is produced. Means are provided to inhibit such output signal in the event of only a momentary decrease of the scatter responsive signal below a predetermined value.

Abstract: A clock circuit comprising a synchronizable voltage controlled oscillator in combination with a programmable address means, which address means is adjusted commensurate with the acoustic velocity of the workpiece, provides clock pulses from the oscillator having a stable and accurate acoustic velocity dependent frequency. An entrant surface responsive electrical signal responsive to an ultrasonic search signal entering the workpiece is also provided to the clock circuit for assuring that the clock pulses are synchronized with the receipt of the electrical signal.

Abstract: A delicate workpiece, such as a semiconductor wafer is cleaned by supporting the workpiece on a shaft which is rotated. A film of liquid solvent is caused to continuously flow across the exposed workpiece surface while the workpiece is in rotation and ultrasonic energy is applied to the liquid film for causing cavitation in the solvent, thereby effecting cleaning of the workpiece surface. Upon shutting off the solvent and the ultrasonic energy, the workpiece is dried by spinning it at high speed.

Abstract: An ultrasonic pulse echo real time imaging system comprises a segmented transducer array formed by a plurality of juxtaposed transducer elements. Successive scans are performed by forming a first predetermined quantity of juxtaposed elements and incrementally shifting said first quantity along said array and subsequently shifting a second quantity of elements along the array, said first and said second quantity being different, for example four and three elements respectively. If the respective quantities are shifted incrementally by one element, the beam axis is stepped by one-half element width only, thereby providing improved image resolution. The image presentation on a cathode ray tube makes use of the interlacing feature, specifically the B-scan presentation line raster responsive to alternate array scans is interlaced.

Abstract: The invention refers to a method of joining two non-fusible workpieces using frictional energy. A first workpiece having a higher melting temperature is provided with a recess extending from the mating surface of the workpiece into the interior thereof. The recess is shaped for trapping material. A static force applied in a direction normal to the mating surfaces of the workpieces to be joined urges the first workpiece into intimate contact with a second workpiece having a lower melting temperature. The workpieces are subjected to relative motion in the plane of the mating surface for causing frictional energy and a softening of the second workpiece. The softened material flows into the recess and solidifies upon cessation of the relative motion. The workpieces are thus joined by virtue of the solidified material trapped in the recess.

Abstract: A cleaning apparatus for cleaning mechanical workpieces, such as bearings, comprises a reservoir for containing a cleaning liquid, a stationary conveyor mechanism partially immersed in the cleaning liquid, and a high frequency vibration source disposed in proximity to and near the bottom of the reservoir. Responsive to the vibration source transmitting vibratory energy via a coupling medium to the cleaning liquid, the workpieces are simultaneously conveyed along the conveyor mechanism and cleansed in the cleaning liquid.

Abstract: An ultrasonic pulse-echo apparatus tests railroad wheels passing through a test zone by sending ultrasonic energy into the rim of the wheels. Sensing means are disposed to discern the type of wheel e.g. locomotive wheel or freight car wheel to be tested and provide a corresponding control signal which adjusts the sensitivity of the test apparatus. This arrangement causes the apparatus to be conditioned for registering relatively small defects in locomotive wheels, but passing over small defects in other wheels which are stressed to a lesser extent, e.g. freight car wheels. Hence, the sensitivity of the test apparatus is continuously responsive to the wheel category undergoing test.

Abstract: A broad bandwidth, constant input impedance programmable attenuator circuit for use in pulse-echo ultrasonic testing is provided for attenuating an acoustic discontinuity responsive electrical signal. The attenuator circuit is programmable either by computer or manually and comprises solid state components, specifically a constant current source and unidirectional current conducting devices. The attenuator circuit exhibits both constant input impedance over a wide range of operating frequencies and immunity from varying output load conditions.