| 摘要 |
1,234,219. Seaming. LECTRATUBE Ltd. 3 June, 1969 [11 Dec., 1968], No. 58820/68. Addition to 1,226,947. Heading B5K. [Also in Divisions B8 and F2] A method of attaching a nozzle or sleeve 7 (Fig. 2) of thermoplastic material, to an end 4 of a metal tube, comprises pressing the sleeve on to the tube by means of pressure head 20, then briefly heating the tube by radio frequency current from induction coils 30 whilst maintaining pressure. The inner surface of sleeve 7 is softened sufficiently to flow around protruberance(s) 6 and/or into grooves on tube 4, thus locking the sleeve on to the tube. The heating period is too short for the outer surface to be softened, so that it may be formed with an external thread for receiving a cap. In another embodiment the tube has a multitude of longitudinal splines, and an annular groove 12 (Fig. 5, not shown), and the sleeve (13) is formed with a corresponding annular bead which partly fills the groove before softening occurs. The metal tube is normally a collapsible thinwall packaging tube formed by impact extrusion. The plastic sleeve may be formed by injection moulding from polyethylene, polpropylene, polyvinylchloride &c. |
