Helically formed tubing welding and cutting same into sections

Claim 1

IN A METHOD FOR FORMING A SUCCESSION OF ATTACHED END-TO-END TUBE SECTIONS WHICH ARE SEVERED FROM EACH OTHER BY CIRCUMFERENTIAL SLITS EXCEPT FOR SMALL INTERCONNECTING PORTIONS INTERRUPTING THE SLITS, THE TUBING BEING FORMED BY HELICALLY WINDING A METAL RIBBON INTO SUCCESSIVE CONVOLUTIONS WHICH ARE THEN JOINED AT THEIR EDGES BY A HELICAL WELDED SEAM; THE STEP WHICH COMPRISES SLITTING THE RIBBON PRIOR TO SUCH WINDING AND WELDING, ALONG SPACED APART LINES WHICH ARE AT AN ANGLE TO THE EDGES OF THE RIBBON SUBSTANTIALLY EQUAL TO THE HELIX ANGLE OF THE CONVOLUTIONS, AND THE SLITS NEAR EACH EDGE OF THE RIBBON BEING INTERRUPTED BEFORE REACHING THE EDGES, WHEREBY IN THE RESULTING SUCCESSION OF TUBE SECTIONS THE SAID SLITS WILL THEN EXTEND CIRCUMFERENTIALLY IN PLANES SUBSTANTIALLY PERPENDICULAR TO THE AXIS OF THE TUBING, AND THE SLITS WILL BE INTERRUPTED WHERE THE HELICALLY WELDED SEAM PASSES FROM ONE TUBE SECTION TO THE NEXT.