GB870821A - Improvements in or relating to sheathing of cables - Google Patents

Abstract

870,821. Making tubing; corrugating. P.S.C. EQUIPMENT Ltd. April 28, 1959 [April 28, 1958], No. 14504/59. Classes 83 (2) and 83 (4). Apparatus for making tubular sheathing for cables comprising means for supplying metal sheet to a tube-forming bending device, a welding device to weld together adjacent edges of the bent sheet to form tubing and means to draw the welded tubing from the machine is characterized in that during the drawing of the tube in an axial direction a groove forming member is urged by a device rotating about the axis of the tube against the inside wall of the tube so that it is helically corrugated. Metal sheet 40, bent up into tubular form 41 as it is fed through bending means 6 and longitudinally seam welded by discs 4, is pulled over corrugating means by a holder 14 secured to a carriage 19 pulled along by an endless chain 10 driven by means 7. When the carriage 19 reaches a stop 20 the machine stops and a length of tubing may be sawn off. The end of the tubing gripped by the holder 14 may be given a conical form. The corrugating means comprises a fixed tube 26 inside the formed tubing in which is rotated by a gear 24 a hollow shaft 28 to which is secured a hollow head 29. A rod 32 axially slidable within the shaft 28 carries within the head 29 a bearing block 30 formed with a recess 35 to accommodate a ball 31. On axial movement of the shaft 28 by a cam 25 the ball 31 is pushed outwardly through an aperture in the head 29 so that as the tubing is drawn over the rotating head 29 a helical corrugation 37 is pressed outwardly from the tubing by the ball 31. More than one ball may be used.