摘要 |
<p>In a method for producing helically wound lock-seam tubing, a metal strip is fed to a forming head in which the tubing is formed. In order to prevent lock-seam slip, a flexible, friction-enhancing string (47) is inserted in the lock-seam (37). An apparatus for such production comprises also a clinching assembly for clinching mutually engaged edge portions (16) of the metal strip, to form the lock seam (37) of the tubing. The invention also relates to a helically-wound lock-seam tube. <IMAGE></p> |