Schweisselement und seine Anwendung

摘要

1,216,943. Welding by pressure. SCREW & BOLT CORP. OF AMERICA. 24 June, 1968 [12 July, 1967], No. 29987/68. Heading B3R. [Also in Division F2] A metal element to be projection welded to a workpiece has an upper surface to which the welding force is to be applied, at least one weld projection having opposed side flanks sloping to diverge towards the element on the under surface of the element a position limit stop projection on the under surface immediately contiguous with one side flank of the weld projection and a relief area on the under surface immediately contiguous with the other side flank of the weld projection, the side flanks engaging the undersurface at positions such that the base of the projection is in a plane inclined relative to the upper surface. The welding element 211 in the form of a bolt or screw having a head and a threaded shank 221 is to be welded to a flat workpiece 10 having a hole to receive the blank 221. The underside of the head has three spaced weld projections 231, the outer sloping sides d1 of which join an outer relief area 20b1 and the inner sloping sides c1 of which join an inner stop or positioning area 20a1. In use the head is engaged by an upper electrode B and the workpiece 10 is engaged by a lower electrode C, current is passed between the electrodes and the projections fuse, the head stop area 20a1 coming to rest on the workpiece 10 and the relief area 20b1 allowing outward flow of fused weld metal. In another embodiment three projections are arranged within an annular stop area and surround a recessed relief area. In yet another embodiment an annular projection is provided within an annular relief area and surrounds a central stop area although the positions of the stop and relief areas may be reversed. A prior art weld element is also described in which three spaced pin like projections are provided, surrounded by an annular rim like stop area. Reference is made to weld nuts.