Patent ID: 6145732
Filing Date: 2000-11-14
Classification: B21C

Abstract:
An apparatus for making a cylindrical helical seamed tube, having a tube longitudinal axis, from a metal strip having a strip longitudinal axis and parallel longitudinal edges being a leading edge adjacent a leading portion of said metal strip and a trailing edge adjacent a trailing portion of said metal strip, said apparatus comprising:a tubing former operable to form said metal strip into a helical tube with said leading and trailing edges juxtaposed, said tubing former defining an aperture with a cylindrical wall;means for continuously feeding said metal strip into said tubing former, said means for continuously feeding operative to maintain said strip longitudinal axis at a substantially constant acute angle with respect to said tube longitudinal axis, said acute angle being between 1 and 25 degrees;first means to apply pressure, after said tube is substantially formed within said tubing former with said leading and trailing edges juxtaposed, on at least said leading edge, leading portion, trailing edge and trailing portion in the direction of said cylindrical wall such that said leading edge, leading portion, trailing edge and trailing portion substantially conform to said cylindrical wall;means for fusing said juxtaposed leading and trailing edges together to form a seam; andmeans for maintaining said leading and trailing edges in a juxtaposed position until said seam cools sufficiently to maintain said juxtaposed position.