Abstract: A flexural spring support for a vibratory apparatus comprises a substantially stationary first member, a second member disposed opposite and spaced from said first member and intended to undergo translating motion in a plane, and a plurality of elongated flexural springs coupling said members to one another. Each spring is provided at its ends with a respective flange, the underside of which is in forced engagement with the surface of the associated member. Adjustable fastening means cause the engagement pressure to be of such magnitude as to prevent relative motion between the flange and member surface when said first member undergoes motion, thereby substantially eliminating fretting corrosion previously manifest at the springs. In addition, each spring is configured to form a clamped clamped constant strain tapered beam.
Abstract: A flexural spring support for a vibratory apparatus comprises a unitary metal body which includes a substantially stationary member, an oppositely disposed spaced member intended to move in a plane, and a plurality of flexural spring beams coupling the members to one another. Each flexural spring beam is constructed as a substantially constant strain tapered beam.
Abstract: Mounting means for a vibratory member, such as an elongate half wavelength resonator, include a pair of cylindrical tubes, each tube coupled with one end to the nodal region of the member and the other end of each tube coupled to a stationary clamping means disposed about the member. The axial length and the thickness of the tubes are selected to enable the tubes to flex radially responsive to the substantially radial vibrations manifest at the nodal region of the member, whereby to decouple the vibrations of the member from the stationary clamping means.
Abstract: An ultrasonic processing method is disclosed wherein during the processing time interval the motional amplitude of the resonating horn and thereby the power to the workpiece is reduced. The reduction in motional amplitude may be in response to a process condition such as a change in dimension of the workpiece or a sharp rise in the power curve, or it may be in response to the lapse of a predetermined time.
Abstract: A method of providing an assembly of thermoplastic parts, which are separable upon the application of a predetermined force, includes assembling at least two thermoplastic parts in an overlapping relation and using an ultrasonically resonant horn for cutting a plug from the wall thickness of the first part and welding the plug to the underlying second part, whereby the upper portion of the plug remains surrounded by the wall of the aperture produced responsive to the cutting of the plug. Responsive to the application of a predetermined breakaway force effective on the plug, the plug breaks away from its attachment to the second part, causing the parts to become separable. The cross-sectional area of the plug is selected to meet a predetermined breakaway force requirement.
Abstract: A method and apparatus are disclosed for joining a plurality of tubular thermoplastic workpieces by causing the workpieces to be stacked with their internal surfaces axially aligned. High frequency vibrations are applied to the respective inner surfaces of the stacked workpieces, the motion of the vibrations being predominantly along the axial alignment of the workpieces. Responsive to the dissipation of the vibratory energy, thermoplastic material from the inner surfaces of the workpieces becomes molten and flows and, upon the cessation of the vibrations, the molten and flowed material rigidifies to cause the workpieces to be joined. The high frequency vibrations, most suitably, are provided by a horn adapted to be resonant as a half wavelength resonator at an ultrasonic frequency in the range between 16 and 25 kHz.
Abstract: A horn for coupling high frequency vibrations from an electroacoustic converter unit to a workpiece, such as is used for welding thermoplastic workpieces by ultrasonic vibrations, is constructed by machining sections of the horn and welding the sections together using electron beam welding or laser beam welding. The respective sections can be made from bar or plate stock.This construction eliminates the machining of deep, inaccessible slots, and as most of the surfaces to be machined are accessible, a fine surface finish can be provided, thus eliminating tool marks which cause the existence of areas of high mechanical stress concentrations when the horn is rendered resonant. Also significant economic advantages are achieved when manufacturing large, massive slotted horns in this manner.
Abstract: In a vapor degreasing apparatus solvent vapor provided by a boiling sump is subjected to further heating for producing superheated solvent vapor to which a workpiece in the process of being cleaned is exposed. The superheated solvent vapor raises the temperature of the workpiece in order to minimize solvent adhering to the workpiece surface as the workpiece is removed from the apparatus to ambient. Further heating is achieved by heating means interposed in the natural convection flow path of the solvent vapor provided by a boiling sump to a vapor zone area in the degreasing apparatus.
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 accommodating 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: Carpeted panels comprising a thermoplastic substrate and a synthetic fiber carpet are produced by bonding the respective parts to one another using a vibration welding apparatus for causing the generation of frictional heat at the interface between the substrate and the carpet. One of the platen of the welding apparatus confronting the carpet is provided with a pattern of closely spaced pins engaging the carpet and urging the carpet into forced engagement with the substrate. On account of the closely spaced pins and the relatively low amplitude of the reciprocating motion, a bond is achieved substantially over the entire interface between the carpet and the substrate.
May 11, 1990
Date of Patent:
June 25, 1991
Branson Ultrasonics Corporation
Sylvio J. Mainolfi, Gerald F. Patry, Henry A. Pensiero
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.
April 6, 1989
Date of Patent:
December 25, 1990
Branson Ultrasonics Corporation
Jean-Guy M. Dussault, Robert L. Polhamus, John E. Willey
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.