Method of making corrugated flexible metal tubing

摘要

A readily adjustable machine which continuously produces corrugated flexible metal tubing from very light gauge metal and of various diameters. A warping ring receives therewithin a longitudinally corrugated narrow strip of formable metal of light gauge and warps the same helically to produce convolutions by means of a helical warping surface which extends into one of the longitudinal corrugations. The size of the tube produced can be varied by merely substituting a warping ring of a different size. A uniquely shaped pair of die-forming rollers have lock-seam forming surfaces which are adjustable relative to each other to provide variation in the degree to which the seam will permit and withstand axial torque. The lock seam is constructed to be symmetrical about the neutral axis of the corrugation and about the slope line of the common corrugation leg of adjacent convolutions which it constitutes. The lock is provided by its radially extending deformations in its longitudinal medial portions and terminal portions, with intermediate portions therebetween extending at about 60 DEG thereto. The terminal portions extend around the bottoms of each of the U-shaped seam elements to further lock them in place. A flying saw automatically cuts off predetermined lengths of the tubing. The length of the sections to be cut may be varied by merely re-positioning a movable switch in the path of the tube. The tube has a unique lock-seam which is constructed to withstand greater flexing, greater axial twist and more stress without damage and without opening, and is stronger.