Patent GB-730990-A (GB)
Title: Machine for making round flexible metal tubes
Inventor: PADGETT PHILIP MARCUS
IPC: B21C37/12
Filed: 1952-12-23
Abstract: 730,990. Coiling helically-jointed tubes. TITEFLEX, Inc. Dec. 23, 1952, No. 32675/52. Classes 83 (2) and 83 (4). A machine for making flexible helically-seamed metal tubes comprises a cylindrical, or slightly tapered, rotatable mandrel, means to supply preformed longitudinally corrugated strip to the mandrel, and a plurality of rotated corrugated rolls spaced around the mandrel to guide and seam the strip, said rolls extending in width to the discharge end of the mandrel. Metal strip 11 unwound from a reel passes through a flux bath 16, which serves to cover the strip with lubricant, through a series of forming rolls 18, which give the strip a longitudinal corrugation with one edge flanged and the other folded over, to a rotating tube-forming mandrel 30. The rolls 18 are mounted in a frame 20 slidable on inclined bars 24 and are driven by belt and pulley means 34,. 32. The belt 34 is so arranged that as the pull exerted by the mandrel 30 on the strip 11 increases and the frame 20 slides down the bars 24 the tension in the belt 34 increases, any slipping between the belt and the pulley 32 stops, and a greater drive to the rolls 18 is exerted and, correspondingly, as the pull exerted by the mandrel decreases the tension in the belt 34 and, thus the drive to the rolls 18, decreases. The shaped strip is guided in a helix around the mandrel 30 and the formed tube is stripped therefrom by a stationary helical cam 115 surrounding the mandrel and corrugated rolls 44, 45, 46, rotated from the mandrel drive means by shafts 64, 65, 66, spaced around, and adjustable to and from, the mandrel and extending in width to the discharge end thereof. The first convolution of the strip on the mandrel is guided between the rolls by a concave faced shoe 125, Fig. 2. As seen in Fig. 5, each roller has the first two or three corrugations, which serve to bring the engaged edges of the strip together and bend and roll them into a tight helical seam, made in one piece and the remainder comprised by a series of identical stepped rings 122. The mandrel 30 is held fast in a hollow drive shaft 131 slidably, but not rotatably, held in a sleeve 142 driven by a gear 50 engaged by a worm 49 on a shaft driven by a pulley 77. In normal operation the mandrel does not move longitudinally but to commence winding on of the strip the mandrel is pulled back by a cap 135 secured thereto through the sleeve 142, and the end of the new strip anchored in a slot in the mandrel end. The mandrel is then moved forward as it is rotated by the engagement of a thrust element 156, secured on the shaft 131 and having an external thread of the same pitch as the strip helix, with a threaded nut section 160, the forward movement ceasing when the element 156 is carried beyond the nut section 160 and the normal working position of the mandrel is reached. To turn the mandrel slowly by hand when initially threading new strip on the mandrel a helical gear 178 on the same shaft as the worm 49 is turned by a helical gear 177 on a shaft 176 turned by a handle 175. This shaft 176 is longitudinally movable so that when the mandrel is driven by the motor, from the pulley 77, the hand drive is automatically disengaged.