GB798495A - Improved mechanism and method for manufacturing tubes and product thereof - Google Patents

Abstract

798,495. Seaming non-metallic sheet materials. AMES IRRIGATION PTY., Ltd. June 26, 1956 [June 27, 1955], No. 19720/56. Class 42 (1). [Also in Groups XXII and XXVIII] A longitudinally seamed tube is made from flat strip stock by forming the strip with edge flanges and bending it to cylindrical shape with the flanges abutting, trimming the flanges, welding trimmed flanges together to form the seam and cold working the welded seam. Metal strip 20 of aluminium, stainless steel, steel, copper or brass from a reel 21 passes over an idler roller 26 to two pairs of flanging rollers 30, 31 and 32, 33, normally idle but driven when the leading end of the strip passes therethrough, which form the strip with flanges 35, then through rolls 38 which help to form a sharp crease at the flanges and under hold down rolls 43. The flanges are cleaned by brushes 47 and the strip is bent up by twisted converging guide stringers 40, 41 having facings 42 which engage the flanges 35 and guide them towards each other. Guide rollers 45, 46 may support the partly formed tube internally towards the end of such operation. The partly formed tube is then brought into cylindrical shape by a cluster 50 of outer rolls 51, 52, 53, 54 and inner rolls 55, 56 the rolls 51, 52 being driven and the roll 51 grooved at 57 to accommodate the now abutting flanges 35. A cylindrical mandrel 60 with longitudinal tube-engaging " Micarta " (Registered Trade Mark) strips 61, 62, 63, 64 supports the tube internally before and after such operation. The tube with the flanges 35 held against one another by guide bars 70, 71 and supported by the mandrel 60 passes to a milling cutter 74 which trims the flanges until they project about the thickness of the metal. The flanges are then welded together by a gas shielded arc welder 80, or by resistance welding, the support or back-up strip 61 on the mandrel 60 having a shallow recess 82 to prevent scorching. A girdle 81 surrounds the tube to prevent distortion during welding. Further to prevent such distortion that part of the strip 20 to form the lower part of the tube may be preheated by gas heaters 83 during the bending up thereof. The welded tube is permitted to cool as it moves along supported by the strips 62, 63, 64 in the mandrel 60 and by another girdle 85 to prevent deformation. The tube then passes through three sets of driven rolls 86, 87, 88 the top rolls 89 of which are preferably slotted, so as not to touch the actual seam, and water cooled. The weld, having been cooled to about 250-300‹ F., is cold worked and flattened between a roll 90 and a back-up roll 91, rolls 92, 93 helping to propel the strip and formed tube. Lengths of the tube may then be cut off by a travelling saw. The strip and tube formed therefrom may be of plastic.