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 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 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: 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: 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 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: 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: 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: A method of producing a corner in thermoplastic flexible channel material having a base portion and at least one leg comprises flattening the leg portion outwardly while folding the material with a "U" bend upon itself to provide an overlapped base and leg portion. Ultrasonic energy is applied to the overlapped flattened leg portion for simultaneously sealing and cutting the overlapped leg portion at an oblique angle to the longitudinal axis of the channel material. Upon releasing the channel material, the material is restored to its original shape, but exhibiting a formed corner.