Patent GB-227602-A (GB)
Title: Method and means for making tubular frames
IPC: B23K37/053
Filed: 1923-12-17
Abstract: 227,602. Meiselbach, A. D. Dec. 17, 1923. Cycles and like vehicles; tubes.-In a method of making tubular frames such as bicycle frames, the sockets and tubular members constituting the frame, are loosely assembled, one of the sockets is fixed in a clamping device and the remaining sockets are forced towards the fixed one so that the joints are completely closed to enable them to be joined by heat, preferably by spot welding, after which the pressure is relieved and the joints are brazed. The clamping device, which accuratelv positions the parts of the frame, comprises a bed 1 carrying a mandrel and a coaxial screw 6 by means of which the crank-socket of a bicycle socket 13 is forced towards the crank-socket bv a screw 11 adjustably mounted by means of bolts and holes 15 on a bracket 3 secured to the bed, the socket having spigots 41 to enter the tubes. The head-socket 33 is clamped by a screw 24 engaging a sliding rod 20 to which is pivoted at 29 a yoke 28 guided by a bracket 36 attached to' to the bed and carrying a half-bearing 47 engaging the socket, the pivot 29 equalizing the thrust in the tubes 38, 39. The slotted plates 51 which support the rear wheel of the bicycle have spigots 55 to enter the forks 50, 52 and are mounted between collars which position them laterally on a shaft 65 carried by a block 66 actuated by a screw 71 to put the forks in compression, the block being mounted, so as to equalize the pressure, in vertical guides 70 slidable on horizontal guides 74. The forks are vieldingly held on the spigots by depressions 82, Fig. 11, so that sufficient pressure will be transmitted to close the joints at the top of the forks while not preventing the bottom joints from Assuming their correct positions irrespective of variations in the lengths of the forks. To space the forks correctly in relation to the wheel tyre, indicated in. section at 59, Fig. 3, brackets 83, mounted on levers 85 pivoted at 86 to the guides 70, have notches to fit over the forks and tubular struts 60 having flanges 87 are forced between the forks by plungers 89 entering holes in the struts and operated by cams 92 on levers 95 pivoted at 93 to the levers 85. When the frame has been put in compression the joints are made rigid by spot welding, cooling being effected by introducing an air blast into the crank socket. The clamping pressure is then removed, the joints dipped first into a flux and next in a brazing material and finally the surplus brazing material is removed. The holes in the sockets are made the same diameter as the interior of the tubes which they receive and a split spigot such as 45, Fig. 13, flanged at 48, is inserted in the ends of the tubes, the three members being welded together as at 49. An eccentric shaft 34, Fig. 1, mounted in the sliding yoke 28, is adapted to enter the head socket and clamp the flanges 48. The holes in the head-socket are cut by an annular cutter 111, Fig. 16, operating in hardened bushes 109 attached to a jig 105 which is made in two parts to clamp the socket 33. The jig is mounted on a block 100 having an inclined' face 102 suitable for cutting the hole 97 and a face 103 for cutting the hole 121. A similar jig is used for shaping the ends of the tubes which are joined to the socket.