GB686126A - Improvements in or relating to the pressure welding of overlapping edges of sheet metal - Google Patents

Abstract

686,126. Making boxes. GENERAL ELECTRIC CO., Ltd., FOXON, H. J., and SOWTER, A. B. May 29, 1951 [June 6, 1950], No. 14138/50. Classes 83 (ii) and 83 (iv). Jointing; welding.-A method of making a closed three-sided corner member from sheet metal comprises cutting out the developed corner consisting of two sides and a bottom, each side being provided with excess material, which is bent at an angle to the remainder of the sides so that when the sides are bent up to form the corner member the excess material of the sides overlaps, the bottom corner being slit inwardly to allow such bending and the overlapping parts being welded down the sides and over the edge to the bottom by pressure welding. In an embodiment of the invention the development of a box is stamped out from sheet aluminium and consists of a bottom B and four sides A which have at each end extensions 2. Each corner of the bottom B has a diagonal slit 3 to facilitate bending of the sides A. In making the box the edges of the sides are bent along the lines 4<SP>1</SP> at an angle of 45 degrees to the remainder of the sides and then the sides are bent on the line I at an angle of 90 degrees to the bottom B. The folded edges, which overlap about # inch, are then cold welded together by means of a triangular section anvil 4, Fig. 4, a press tool 5 and clamps 6. The tool 5 comprises a central member 7 having a flat surfaced projecting welding tongue 10 and two end members 8 and 9. The height of the tongue 10 increases as it approaches the end member 8 for welding around the corner of the box. The anvil 4 has a grooved flattened apex, the groove 14 of which lies directly under the tongue 10 of the tool 5. One end of the flattened apex is radiused to form the inside bottom corner of the box. The central member 7 of the tool has recesses 15 along each side of the tongue 10 and during the welding operation metal is forced into the recesses 15 as well as the groove 14 and so improves the outside appearance of the welded corner. The welded corners are water-tight and the invention may be applied to making boxes whose sides are not at right angles to the bottom.