GB1138470A - Process and apparatus for electrical resistance-welding of sheet edges - Google Patents

Abstract

1,138,470. Welding by pressure. TAGERS G.m.b.H. 18 Jan., 1966, No. 2380/66. Addition to 1,100,851. Heading B3R. In the electrical resistance welding of two edges of a metal sheet or sheets the ends of each of the edges is bent up, the bent up edges are overlapped, forces are applied which tend to bring the bent up edges into close face contact, electrodes are pressed into contact with the overlapping edges in a direction normal to the portions of the sheet or sheets adjacent the bent up edges and current is passed through the sheet or sheets. The ends of a tinned steel strip are bent upwardly and downwardly respectively at right angles to the strip and the strip is formed into a cylindrical can body with the bent ends 3, 4, Fig. 1, abutting on their inner faces and an upper electrode 11 is engaged with the part of the strip adjacent the end 4 to overlap the end 4 and a lower electrode 12 is engaged with the other part of the strip to overlap the end 3. The electrodes extend the length of the edges. An insulated counter pressure member 14 is arranged to abut the outer face of the end 4 and a similar member 13 is arranged to abut the outer face of the end 3. In operation the members 13, 14 press the ends 3, 4 together in directions H, the electrodes 11, 12 are then forced against the strip in directions V, normal to directions 14, and current is passed between the electrodes. The welding apparatus may comprise upper and lower electrodes 11, 12, Fig. 2, carrying strips 13, 14 in recesses 19, 20 with an elastic material 21, 22, e.g. rubber, between the strips and the recesses. The lower electrode 12 is fixed and the upper electrode is movable vertically and horizontally, the latter by an eccentric 24. If the upturned edges are not bent sharply the edges, while pressed together, do not lie in face contact until current is passed to effect their softening. The upturned edges may first be pressed together with a high pressure to produce contact therebetween and the pressure is then reduced before a current impulse is applied. The electrode contact pressure before the current impulse is less than that after the impulse.