GB477526A - Improvements in the manufacture of hollow tubular metal members - Google Patents

Abstract

477,526. Making helical tubes. McMINN, W. W. June 30, 1936, No. 18132. Convention date, July 5, 1935. [Classes 83 (ii) and 83 (iv)] Coiling ; soldering.-In making cylindrical or tapered helical metal tubes, particularly for golf club shafts, a metal strip is helically coiled to form the tube which advances axially and rotates from the place of winding, and a number of convolutions are simultaneously heated by passing the blank through a high temperature heating zone and the seam united solely by bonding metal of lower melting point than that of the strip. The tubes may be finally cut off into lengths. The seam may be of the butt or bevelled overlap type. The strip, preferably of steel, may be fed by rolls 12 against dies 14 to coil it into a tube which rotates and moves axially through an electric induction furnace 20. Reducing gas, such as hydrogen, may be fed to the interior of the tube by a pipe 26 and to the exterior of the tube by a pipe 28. A brazing wire 30, having a copper base, may be fed by rolls 32 and on melting is drawn into the seam by capillary attraction. Flux may also be supplied. If excess of solder is fed, the tube may also be coated internally or internally and externally therewith. To obtain a sealed externally coated tube, the solder is fed to the exterior of the tube. An induction furnace may be used in combination with a resistance furnace to effect the brazing. After passing through the furnace 20 the tube may be quenched by oil, water or air projected from a perforated coil 36 and may then be passed through an electric resistance furnace 44 for tempering purposes. In order to keep the edges of the tube in close contact, one or more rollers 46 driven at the same or greater peripheral speed than the rotation of the tube may be used. The tube is supported by rollers 48<1> after passing through the furnace 44. In making lap-jointed tubes, the strip may be passed from the feed rolls through a second pair of rolls to form an offset flange on one edge. The brazing wire may pass under the strip through a groove 62 in one of the guide jaws and be fed by the strip or assisted by a driven knurled roller 66. The brazing wire is thus coiled in the interior of the tube.