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: 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.