Abstract: A method is provided for preventing tip sticking during the spot welding of workpieces including ultrasonic vibratory spot welding. The welding apparatus includes a welding tip and a complimentary anvil between which the workpieces to be welded may be inserted. The welding tip is adapted to introduce into and through the workpieces sufficient amounts of energy to effect a weld between the workpieces. Shim material is inserted between the welding tip and the workpieces and/or between the anvil and the workpieces, said shim material having a hardness greater than the hardness of the workpieces. After insertion of the shim material, welding energy is then introduced through the shim material and the workpieces and welds are effected therebetween. The shim material is then torn away and discarded. Apparatus for effecting this method is further provided.

Abstract: Method and apparatus are provided for use in an ultrasonic vibratory welder for pre-heating the workpieces prior to welding and, thereafter, for continuously monitoring the temperature of the anvil and of the welding tip during subsequent welding operations to insure their temperature remains within a pre-determined range during the entire welding cycle. It has been found that weld characteristics, particularly weld size, shape, configuration and strength are dependent upon the temperature of the anvil and welding tip. Thermostatically controlled resistance heating means are provided in the anvil and/or in the welding tip for pre-heating of the workpieces. Automatic control means, are also provided for alternately heating and cooling the anvil and welding tip during the welding cycle.

Abstract: Ultrasonic spot welding apparatus is provided including a welding tip and a complimentary anvil, both mounted on a stationary welding frame and between which workpieces may be inserted for welding. The welding tip includes a vibratory reed adapted to introduce into and through the workpieces high frequency vibratory energy in order to effect a weld between the workpieces. The apparatus includes a reed stabilizer for clamping about and stabilizing the vibratory reed at its nodal point and clamping means for clamping the workpieces. The clamping means are mounted on a clamping frame which is pivotably mounted to the stationary welding frame.

Abstract: Ultrasonic vibratory spot welding apparatus is provided, said apparatus being of the type including a welding tip adapted to introduce into and through at least two workpieces high frequency vibratory energy so as to effect a spot weld therebetween. A complimentary anvil is also provided and so positioned relative to said welding tip so as to define a throat therebetween between which the workpieces are adapted to be inserted for spot welding. Means are provided about either or both the welding tip and the anvil for preventing step shearing during the welding operation, said means comprising a shield positioned about the welding tip and/or the anvil. The shield preferably includes an inner and an outer layer, said inner layer being fabricated from either an organic material or a plurality of metallic materials. The outer layer, which is fixedly attached to either the welding tip and/or the anvil, is fabricated from a metallic material which has modulus lower than the modulus of steel.

Abstract: A fastener plate is provided for use in securing together structural elements. The plate includes a base plate to which is ultrasonically welded at least one fastening element which may include, for example, an externally-threaded, stud-like fastening element, or an internally-threaded fastening element. A method for fabricating said plate is further described, said method comprising the steps of locating said at least one fastening element on said base plate and then ultrasonically welding said element to said base plate using an ultrasonic welder which includes a center aperture and which is adapted to effect a weld between the annular base portion of the fastening element and the base plate. In an alternative embodiment, at least one locking ring may be used to overlay the annular base portion with the weld being effected between the ring and the base portion.

Abstract: A method of progressively ultrasonically welding together workpieces is provided wherein the spot welds effected are initiated as small points and then progressively grow to full size. The method employs an ultrasonic welding apparatus of the type having a welding tip and a complimentary anvil between which the workpieces to be welded may be inserted. The workpieces are first clamped together and the workpieces "presqueezed" to disperse any adhesives which may be used between the workpieces. Initial pressure and energy levels are then introduced to "scrub" the workpieces. Pressure and energy are then synchronously ramped in phase to maximum levels to effect a weld between the workpieces. The welding operation is controlled by control means which permit automatic synchronization of the operation.