GB1137980A - Joining overlapped metal sheet edges - Google Patents

Abstract

1,137,980. Welding by pressure; soldering. P. OPPRECHT. 23 Sept., 1966 [24 Sept., 1965], No. 42626/66. Heading B3R. In joining overlapped sheet metal edges of which the facing surfaces are coated with low melting-point metal the overlapped edges are resistance welded by wire-like electrodes having a small contact area with the outer surfaces of the overlapped edges and advancing with the edges and after being welded the edges are squeezed together so that the melted lower melting-point metal is distributed to reduce the risk of corrosion after it has solidified. Tinned or galvanized sheet iron shaped to form a can body is introduced with its edges 44, 46, Fig. 4, between the electrode rollers 5, 7, Fig. 1, of a welding machine having a wire 9 forming a moving electrode surface passing over each of the rollers 5, 7. The electrode 7 is carried on a lower fixed arm 1 and the electrode 5 is on a pivoted upper arm 3 and lower roller 19 is carried on bracket 21 on the arm 1 to cooperate with a roller 15 on a pivoted arm 13. The roller 15 is driven from the electrode roller drive but both rollers may be driven. The can body passes between the rollers 5, 7, whereby the weld 48 is produced and the welding heat causes melting of the tin coating which flows between the overlapped part 44, 46 pressed together by the rollers 15, 19. The can body then passes a nozzle 23 which sprays a protective film 52. In a modified machine the rollers for exerting pressure subsequent to the electrode rollers are both idlers. A separate heating source may be provided between the electrode rollers and the pressure applying rollers and both sides of the overlapped edges may be sprayed with the protective film.