| 摘要 |
PURPOSE:To achieve equally strong connection by reducing the diameter of a lock ring, on the outer peripheral surface of which a tapered surface is provided, to almost equalize the gap between inner circumferential surface of a socket welding joint and the outer peripheral surface of a thermoplastic resin tube, then by generating heat with a heating element, and by connecting the socket welding joint and the thermoplastic resin tube that are in close proximity, together. CONSTITUTION:When polyethylene tubes 1, 2 are to be connected together, the end part of the tube 2 is inserted into a socket 12 of a socket welding joint main body 11, which is provided on the end part of the tube 1, and then a cap nut 3, which is threaded in a male screw 15 formed on the outer surface of the end part of the joint main body 11, is screwed. Since the inner surface of the cap nut 3 is tapered, the diameter of a lock ring 4, the outer surface of the end part of which is also tapered, is reduced, and its inner surface is brought into pressure contact with the outer surface of the tube 2. The gap between the socket 12 and the tube 2 is equalized on the entire circumference of the tube 2. A heating element 13 is electrified through an electrifying element 14, to generate the heat, and the inner surface of the socket 12 or the outer surface of the tube 2 that are in close proximities, are melted, and the socket 12 and the surface of the tube 2 are welded into an integrated manner. |
