Abstract: This invention provides a method of producing a series of substantially uniform spot welds between two metal parts using a servomotor driven movable electrode and an axially opposing fixed electrode. Target values for electrode displacement in producing a weld indentation and electrode squeeze force are determined for the electrodes and workpieces. During welding operations electrode displacement and electrode force measurements are continually taken and compared with the displacement and force target values. While the measured values are within a tolerance range of the target values, welding is continued using the preset parameters. When either or both of the measured electrode displacement or force value falls outside the target range the total welding current is adjusted in small increments to correct the displacement and/or force values and, thereafter, welding is continued using the new total welding current.

Abstract: A friction stir rivet is rotated and driven through a first fusible workpiece into an engaged second fusible workpiece, causing local portions of the first and second workpieces to plasticize. A slideable cap contacts the exposed surface of the first workpiece shortly after the process begins. The contact causes the cap to act as a retaining element, limiting the escape of plasticized material from stir site. Once the rivet is driven into the first and second workpieces, rotation ceases and the plasticized material hardens around the rivet. A weld is thus created, joining the workpieces and encompassing the rivet, which provides additional mechanical strength.

Abstract: This invention provides a design of an adhesive encapsulated blind rivet for joining an assembly of overlying parts having an accessible side and an inaccessible side. The rivet comprises a rivet head and tubular rivet body. A mandrel is inserted through the open end of the tubular rivet body and through a mandrel hole in the rivet head. A mandrel head engages the end of the tubular body. The tubular body is filled with a mass of latent adhesive around the mandrel. The rivet body is longer than the thickness of the parts to be joined to accommodate a substantial amount of adhesive for expulsion through holes in the rivet body located within the thickness of the assembled parts. The portion of the rivet body extending beyond the blind side of the assembled parts is weakened in a pattern of corrugations or other bands for folding of the end of the tubular body in setting the blind side of the rivet and expelling the larger quantity of adhesive against and between the riveted parts.

Abstract: An article suitable for laser-welded metallurgical bonding, the article having a first part having a lower surface, and a second part having an upper surface is disclosed. The lower surface of the first part is disposed at the upper surface of the second part to provide for a faying surface thereat. The faying surface has a plurality of channels with a depth equal to or greater than about 1 micron and equal to or less than about 1000 microns. The article is suitable for laser-welded metallurgical bonding at the faying surface. The plurality of channels has a repetitive pattern of channels arranged along a path of the faying surface in a direction of the metallurgical bonding action.

Abstract: The present invention provides a method of joining a sheet metal part to a metal tube to form an assembly. In an overlapping configuration, the parts are held together under a clamping force while a self-piercing rivet is driven through the assembly by a welding electrode. The rivet pierces and passes through the sheet metal part and then through at least substantial portion of the metal tube to thereby form a mechanical interlock. An electrical current is then applied to this mechanical retention to melt a portion of the rivet as well as a portion of the metal surrounding the joining region. The flow of electrical current is then stopped after several welding cycles where the now melted material is allowed to solidify upon cooling, thereby forming a weld.

Abstract: A sheet metal assembly includes first and second metal sheets having flanges extending from the sheets. The flanges overlap and are in engaged parallel facing relation for a width between outer edges and flanges. At least one pair of self-piercing rivets joins the flanges at spaced locations along the width. The rivets each have a head and a shank extending into the flanges from opposite sides. The rivet heads of each pair are located in opposite flanges and are spaced further from the outer edges of their respective flanges (nearer the load-application ends) than are the shank portions of other rivets of the pair.

Abstract: The present invention is a self-piercing rivet wherein the hollow shell has an external axial asymmetry wherein the asymmetry is with respect to the axis of rotation of the hollow shell. Once installed in a stack of sheets, the asymmetric self-piercing rivet prevents relative sheet rotation of the sheets relative to the axis because of rotational interference caused by the external axial asymmetry of the hollow shell.

Abstract: Mechanical and adhesive charged blind fasteners have an annular one way flat or O-ring seal mounted at one end of a cylindrical rivet body sealingly engaged with an axially extending mandrel stem to provide a torodial chamber. The body has radial adhesive-extruding openings therethrough around which a vacuum may be established for initial adhesive charging purposes. For charging, the seal is deflected by the force of a flow of adhesive from a supply responding to the establishment of a positive pressure differential between the supply and the exterior of the body. With the torodial chamber opened, viscous adhesive readily flows therein from the supply. After being filled, the vacuum is terminated and the seal naturally recovers and closes the body to confine the adhesive therein. Adhesive charging can be achieved by other mechanisms that impress a load on the supply to effect seal opening.

Abstract: The present invention is a self-piercing rivet wherein the hollow shell has an external spiraling, wherein the spiraling is with respect to the axis of rotation of the hollow shell. Once installed in a stack of sheets, the spiraling prevents the riveted sheets from mutually separating and the rivet loosening with respect to the sheets.

Abstract: A blind rivet system including a number of parts to be joined that have aligned holes. A tubular rivet body is disposed in the aligned holes and includes a rivet head portion and a sleeve portion. The head portion and sleeve portion include a longitudinal bore. A mandrel having a head portion greater in diameter than the bore and a shaft portion is disposed within the longitudinal bore. An adhesive is disposed in an annular space defined by the interior surface of the bore and an exterior surface of the shaft portion. An installation tool having a seal intersects with the rivet head portion such that when the head portion is drawn within the bore during installation, the adhesive is maintained within the tubular rivet body and extruded from the annular space to a region between faying surfaces of the parts to be joined.

Abstract: Method and apparatus for detecting unacceptable misalignment of welding electrodes. An electrode-alignment station is positioned adjacent a welding station. A robot controls the movement of the electrodes, and occasionally moves the electrodes out of the welding station and into an electrode-alignment station. At the electrode-alignment station, the electrodes are closed on a fixture that transfers electrode-misalignment into movement of a plate that triggers an alarm if the misalignment is greater than a prescribed amount.

Abstract: A sheet metal assembly includes first and second metal sheets having flanges extending from the sheets. The flanges overlap and are in engaged parallel facing relation for a width between outer edges and flanges. At least one pair of self-piercing rivets joins the flanges at spaced locations along the width. The rivets each have a head and a shank extending into the flanges from opposite sides. The rivet heads of each pair are located in opposite flanges and are spaced further from the outer edges of their respective flanges (nearer the load-application ends) than are the shank portions of other rivets of the pair.

Abstract: A sheet metal assembly includes first and second metal sheets having flanges extending from the sheets. The flanges overlap in parallel for a dimension. A shim is disposed between the flanges and extends to the outer edges thereof. A weld joins the metal sheets through the shim. The shim increases the mechanical strength of the assembly. The increase in mechanical strength from the shim allows for reductions to the flange width. As a result, a lighter assembly of equivalent strength is produced.

Abstract: A joint assembly for joining first and second tubular members. The first member has flanges extending from walls of an end segment. The walls of the end segment define a receiving opening. The second member has walls and a protrusion having sides extending from the walls to an end of the protrusion. When the members are joined the protrusion is received in the opening of the end segment so that the sides of the protrusion are in facing engagement with the walls of the end segment and the flanges engage the walls of the second member. The members are secured together at some of the engaging surfaces. The protrusion reduces stress on the flanges and increases the mechanical strength of the assembly.

Abstract: A laser is used to melt portions of first and adjacent workpieces to form a weld. As the laser melts the workpieces, a powdered metal is injected into the molten metal pool. The powdered metal improves the strength of the weld by providing additional weld volume to bridge any preexisting gaps between the workpieces. The molten metal is then cooled to form a weld between the workpieces. For welding galvanized steel or metals with coatings or alloy materials having a lower vaporizing temperature, a powdered metal is used that reacts with the lower temperature metal to form an alloy that avoids vaporization during welding, thereby reducing weld porosity and weld spatter.

Abstract: A rivet and method for riveting metal members, and particularly, metal sheets is disclosed. The apparatus includes a rivet assembly for driving a piercing rivet into stacked metal sheets and a die for assisting in supporting the sheets during driving of the rivet and for assisting in securing the rivets to the sheets. The rivet of the invention includes an adhesive that is forced through passages in the rivet for assisting in fastening the rivet to the sheets and for assisting in fastening the sheets to each other with greater strength.

Abstract: The present invention provides a method of joining a sheet metal part to a metal tube to form an assembly. In an overlapping configuration, the parts are held together under a clamping force while a self-piercing rivet is driven through the assembly by a welding electrode. The rivet pierces and passes through the sheet metal part and then through at least substantial portion of the metal tube to thereby form a mechanical interlock. An electrical current is then applied to this mechanical retention to melt a portion of the rivet as well as a portion of the metal surrounding the joining region. The flow of electrical current is then stopped after several welding cycles where the now melted material is allowed to solidify upon cooling, thereby forming a weld.

Abstract: This invention provides a method of welding a cage and nut combination to a surface of a workpiece using a welding electrode as a holding and locating member for the cage and nut. The cage and nut are placed, up-side-down, in a recess formed in the welding tip of a lower electrode which is positioned vertically with its tip up. The workpiece backed by an opposing welding electrode are positioned above the electrode holding the inverted cage. The inverted cage and workpiece are pressed together along a vertical axis and electrically welded. The lower electrode with its recess serves to accurately locate the inverted cage with its weld material projections for uniform welding contact with the surface of the workpiece for more efficient welding setup and an improved welded bond between the cage, retaining a nut, and the workpiece.

Abstract: This invention provides a method of welding a cage and nut combination to a surface of a workpiece using a welding electrode as a holding and locating member for the cage and nut. The cage and nut are placed, upside-down, in a recess formed in the welding tip of a lower electrode which is positioned vertically with its tip up. The workpiece backed by an opposing welding electrode are positioned above the electrode holding the inverted cage. The inverted cage and workpiece are pressed together along a vertical axis and electrically welded. The lower electrode with its recess serves to accurately locate the inverted cage with its weld material projections for uniform welding contact with the surface of the workpiece for more efficient welding setup and an improved welded bond between the cage, retaining a nut, and the workpiece.

Abstract: This invention provides a method of welding a flange nut to a workpiece surface using an improved design of a welding electrode. The electrode comprises a parts-receiving recess adapted to receive a stem portion of the nut, while maintaining a clearance between the recess and the stem. This clearance allows electrical current to be directed toward the flange portion of the nut. As a result, electrical contact between the workpiece and projections underlying the flange is greatly improved, thereby produce higher quality spot welds and increasing the life of the electrode tip.