GB238214A - - Google Patents

Abstract

238,214. Junkers, H. Aug. 9. 1924, [Convention date]. Posts and columns; rods and bars. - Corrugated sheet metal for flying machines or boats &c. formed with flattened portions so as to facilitate riveting or welding together or to other parts such as bulk heads &c., by first transforming each corrugation into several smaller corrugations. Each corrugation 1 is transformed into two smaller corrugations 4 which are then converted into a flattened edge 3, Fig. 3. In a modification each crest and also each trough are first transformed into two smaller corrugations so that the flattened edge is on the neutral axis between the crests and troughs. In Fig. 5, the small corrugations 4 are acted on to form a flattened rim below the level of the troughs so as to bear tightly against the part to which it is riveted through the troughs. In cases where the corrugations are oblique to the edge of the sheet the small corrugations are similarly formed obliquely. For very large corrugations each may be then transformed into two still smaller ones and so on until the corrugations are small enough to be flattened out. Flat transverse strips. map be produced in the body of the sheet either of oblique, curved or other form, and corrugated circular lids may also be provided with fiat rims. The operation is effected by one pair or successive pairs of swages, which may be wide enough to cover several of or all the corrugations. One pair of swages 11, 12, Fig. 7, may be formed with the required operative surfaces to complete the operation in one stage or in several stages by moving the swages progressively over the sheet from the edge inwards to the first position shown, one pair 13, 14, Fig. 14 or separate successive pairs of swages may be used to produce the small corrugations and a pair 16, 17, Fig. 15 to effect the flattening.