Abstract: A two step process for ultrasonically welding together first and second thermoplastic pieces and welding a membrane between these two pieces. The first piece comprises an annular bead, the second piece comprises an annular energy director. The method comprises first ultrasonically cutting and sealing the membrane to the first piece using an anvil comprising an annular projection and at the same time creating a groove in the first piece. The annular bead is ultrasonically melted and thus welds the membrane to the first piece. The first and second pieces are then brought together so that the groove and energy director are aligned. Under ultrasonic action, the energy director melts within the groove creating a strong weldment without any voids or material flashing.

Abstract: A method and apparatus for cleaning printed electrical circuit boards having surface mount components by ultrasonic energy in the frequency range between 300 kHz and 1.0 MHz. The ultrasonic energy is produced by an array of piezoelectric wafers mounted to the inside surface of an immersible transducer assembly which, in turn, is disposed in a tank accomodating a bath of cleaning liquid. The ultrasonic energy provided by the transducer assembly and the circuit board to be cleaned are disposed to cause the ultrasonic wave beam to be incident upon a board to be cleaned at an angle of 90.+-.60 degrees relative to the surface plane of the board. This arrangement will remove solder flux residue and other contaminants from spaces ranging from 0.001 to 0.010 inch present underneath a surface mount component.

Abstract: An ultrasonic power supply for driving a piezoelectric transducer at its parallel resonant frequency includes a clamped-mode resonant converter for converting direct current to alternating current and a demodulator, a loop filter and a voltage controlled oscillator in a phase locked loop configuration. The power supply also includes a control circuit for adjustably setting and controlling the amplitude of vibration of the transducer, and providing during start-up a ramp start. The power supply, further, includes a control circuit for limiting the maximum permissible current flow to the transducer and the reverse current flow from the transducer resulting from stored mechanical energy. Both control circuits provide feedback signals which control the pulse width modulated operation of the clamped-mode resonant converter and thereby control the voltage amplitude of the alternating current output from the converter.

Abstract: A method and apparatus for separating monofilaments, such as glass or carbon monofilaments, forming a strand, is achieved by feeding the strand in a curved path over and in forced contact with a plurality of rods, each being subjected to vibrations. The vibrations, applied transverse to the axis of the strand, provide intermittent localized contact between the filaments and the rod surface, hence preventing high tensile and shear forces which cause breakage of the delicate filaments. In one embodiment, the rods comprise a plurality of resonators dimensioned to be resonant along their longitudinal axis for a predetermined frequency of vibration. The resonators are energized with vibrations from a single resonator dimensioned to operate as a half wavelength resonator. The resonators are provided with a wear resistant, smooth surface coating at the area of contact with the filaments.

Abstract: Assembling of two workpieces by the ultrasonic staking or riveting method comprises the providing of a first thermoplastic workpiece having an upstanding stud, an apertured second workpiece juxtaposed on the first workpiece so that the stud protrudes through the aperture of the first workpiece, and a horn applying ultrasonic energy to the upstanding, free end of the stud by forced contact between the stud end and the horn. The improvement comprises the application of ultrasonic energy to the horn during brief time periods which alternate with brief time periods during which the horn, while still in contact with the stud end, is substantially inactive.

Abstract: A blade-shaped high frequency resonator for welding sheet material without a gap, when resonators of this shape are disposed in an array, includes at its output surface a pair of laterally extending ears, each ear terminating in end surfaces configured to interface with the end surfaces of a similarly shaped juxtaposed resonator. Each ear is dimensioned to cause the sum of the moments about the lateral axis of the resonator to be substantially zero. Typically, the lateral end surface of a respective ear is of a zigzag configuration. The end surface intersecting the lateral resonator axis intersects such axis at an angle of less than ninety degrees.

Abstract: The method of closing an open ended thermoplastic body with a thermoplastic sheet material comprises the provision of a groove in the thermoplastic body and a protrusion disposed on the output surface of a horn adapted to be resonant at an ultrasonic frequency. The protrusion of the horn is dimensioned to enter the groove and force the sheet material into contact with surfaces forming the groove for achieving, when the horn is rendered resonant, a weld between the sheet material and the body, the weld being confined to the surfaces forming the groove.

Abstract: An apparatus for joining sheet material and cutting joined material comprises a set of drums rotating against one another. A first drum is provided along its surface with a raised pattern serving as welding surfaces when operating in conjunction with one or more ultrasonic resonators. As sheet material is fed through the nip formed between the drum and the resonator, the material is joined in accordance with the pattern. A second drum is provided along its surface with a complementary raised pattern of cutting surfaces. As the material subsequently is fed through the nip between both drums, the welded portions are severed from the surrounding material. The welding and cutting pattern surfaces are constructed to mesh for providing positive severing of the material interposed therebetween.

Abstract: Thin plastic film is welded by ultrasonic energy by placing two layers of film upon one another on a supporting surface having a cavity. A source of ultrasonic energy, such as a resonator, is brought with its output surface in close proximity to, but non-contacting relation with, the exposed surface of the films for coupling ultrasonic energy via a thin air or gas column to the films at the area of the cavity. The dissipation of ultrasonic energy causes a weld and when the films are moved relative to the resonator output surface and supporting surfce, a seam weld is achieved.

Abstract: The invention concerns resonators of rectangular or blade like configuration providing substantially uniform motional output along the output surface. The improvement is achieved by disposing the change in cross-sectional area for producing increased motional amplitude at the output surface in relation to the nodal region of the resonator in such a manner as to cause the lateral portions of the resonator to exhibit a greater motional amplitude gain than that of the central portion.

Abstract: A conveyor system comprises a runway rail in the form of an extruded hollow body of oblong cross-section. The runway rail has a top portion which includes a pair of parallel surfaces including between them an angle. A similar pair of parallel surfaces is disposed at the bottom portion of the runway rail, which surfaces are parallel to respective surfaces of the top portion and include the same angle. A crab having load and guide wheels is disposed on the runway rail, the load wheels engaging the pair of surfaces at the top portion and at least one guide wheel engaging one of the surfaces at the bottom portion. A driving motor mounted to the lateral flange of the crab is adapted to drive the crab along the runway rail by engaging a stationary drive element mounted to a side rail of the runway rail. A hoist mounted to the crab serves to raise and lower work pieces.

Abstract: A fixture for use in conjunction with welding workpieces by vibration welding including a pin adapted to assume two states, namely a first state in which the pin is movable to seek an aperture in the workpiece and is free to enter such aperture, and a second state in which the pin is rigidly fixed. The pin is attached to a plate which responsive to fluid pressure is either free to float in a generally lateral direction, or is clamped rigidly between two superposed plates.

Abstract: An anvil for our ultrasonic textile slitting apparatus comprises an elongated, flat, substantially rectangular, housing in which two pistons are disposed for motion relative to one another along the longitudinal axis of the housing. A first piston, responsive to fluid pressure, is urged against the force exerted by springs into motion toward the second piston for causing the second piston, which is provided with a slitting implement, to be urged toward contact with the output surface of an ultrasonic horn. Further, springs are interposed between the first and the second piston for urging the pistons apart, but becoming compressed responsive to such fluid pressure. The combination of fluid pressure and springs causes the slitting implement to be kept in continuous contact with the horn despite the very high acceleration forces manifest at the horn output surface. In addition, the springs provide vibratory isolation from the vibratory energy of the horn.

Abstract: The method of joining two thermoplastic workpieces by ultrasonic energy along respective confronting surfaces includes providing one workpiece surface with an energy director while the opposing other workpiece surface contacted by the energy director exhibits a rough textured surface, rather than a conventional smooth surface, and an article manufactured according to such method.

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 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.