GB202487A - Improvements in or relating to the manufacture of metal pipes - Google Patents

Abstract

202,487. Colby, F. W. July 20, 1922. Pipes with helical seams are made by bending both edges of a strip to form unequal upstanding margins part of each of which is also bent downwardly parallel to the upstanding part, then coiling so that the narrower margin enters the recess between the parallel parts of the wider margin and then pressing the parallel interengaging parts of the edges together. A metal strip is passed, preferably by a pair of feed rolls 13, through a series of pairs of rolls, 1, 3, 5, 6, 8, 10, which successively bend the edges so as to form finally a strip having hooked edges 17, 16, Fig. 14, of which the edge 17 is shorter than the edge 16, as shown in Fig. 17. The rolls of each pair are connected together by gearing and are all driven by gearing from the shaft 39. The bent strip is first passed by hand round and is then coiled about an inclined mandrel 15, the edge 17 first passing through a pair of rolls 20, 21, Fig. 3, so as to stretch it in order to allow for the greater diameter of the rib in forming the pipe. The faces of the rolls are preferably inclined so as to stretch the outer portion more than the inner portion. During the coiling operation the edge 17 passes up between the overlapping portions of the edge 16 as shown in Fig 17. The parts in this condition then pass through a pair of rolls 18, 19 which bend the part 59, Fig. 15, of the edge 16 against the edge 17 so as to compress them together and at the same time stretch the edge 16. The two pairs of rolls are driven from the shaft 39 by bevel gear 38, 37, 35, 34, 32, 31, and spur gear 23, 24, 25, 26, 27, 29. The parts of the seam may be further compressed by a pair of rolls 56, 57, shaped similarly to the rolls 18. 19. These rolls are driven from the spur-wheel 25 by a spur-wheel on a shaft 61 which is connected by bevel gear to a shaft 64, which through bevel gear 65, 66, and spur gear 68, 69 drives the roll shafts. The seams are preferably left upright and may be further connected together by spot welding or riveting.