GB264534A - A method of and apparatus for making metal tubes by bending metal strips between pairs of rolls of consecutive shapes - Google Patents

Abstract

264,534. Kozicz, J. Jan. 16, 1926, [Convention date]. Tubes. - In the manufacture of tubes from a metal strip by progressively bending the strip between successive pairs of profiled rolls the strip is subjected to pressure in the vicinity of its longitudinal edges only, the distance between the top and bottom rolls of the forward pairs of rolls being smaller at the outer edges than in the middle in the case of a metal strip of uniform thickness. Fig. 1 shows the first pair of rolls A, with the marginal space p less than the space m in the middle, the absence of pressure on the middle portion of the strip preventing excessive generation of heat and enabling lubrication of the strip to be dispensed with. Collars b and grooves c on the rolls prevent lateral displacement. In the second and third passes the strip is brought to the forms shown in Figs. 2a and 3<a>, and then to the form shown in Fig. 4<a> by the rolls D, Fig. 4, the upper roll D having a disc D<1> passing through the seam of the tube to guide it in a straight line. The shaping is completed by rolls disposed behind the rolls D and a welding device may be disposed behind the finishing rolls. Instead of the circular shape shown, tubes of oval, right angle, square, &c. shape may be made, and a number of different sections may be formed by changing the last pair of rolls only without exchanging the forward rolls. The Specification as open to inspection under Sect. 91 (3) (a) states that the guide disc D<1> bears on the inside of the strip resting on the bottom roll. This subject-matter does not appear in the Specification accepted.