| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the formation of an oxide film on a fusion face in fusing a small-diameter pipe outer face and a large-diameter pipe inner face by fusing adjoining covered wires incorporating a linear heating element and composed of a thermoplastic polymer material in parts except for the outer face and inner face of a spiral and by fixing them so as not to be separated from each other. SOLUTION: Resin in parts except for the outer face and inner face for a spiral touching the top/bottom faces of each sinking comb 5a of a heating plate 5 which are inserted between adjoining covered wires 1 of the spiral 6 incorporating a nickel wire 1a, move along a spiral covered wire contact part, and are heated to the melting temperature of a polyethylene coating material or more is melted in order, fused, and fixed not to be separated therefrom, thus formed into a joint sleeve. In this case, the melt resin is quickly fused by touching with the sinking comb 5a by its passing so that the melt resin can be suppressed from oxidized by the contact with the atmosphere (oxygen) to the minimum. This constitution can prevent any obstruction of the appropriate fusion between the small-diameter pipe outer face and the large-diameter pipe inner face by interposing an oxide film on the fusion face.</p> |
