| 摘要 |
The invention relates to electrofusion couplers (1) and has for its objective to enable the employment of relatively thin wire electrical resistance heating wire (5) with a substantial guarantee of uniform heating along the length of the coupler with an equally substantial guarantee of the absence of shorting between adjacent turns of the wire. This objective is met by a construction comprising a sleeve-like coupler (1) with a winding of electrical resistance heating wire over a length of its bore, the said winding being composed of a number of wires connected in parallel. Preferably, a number of lengths of wire are embedded in a ribbon of plastics material (4), the ends of the wires being exposed, connected together and attached to a terminal. The ribbon may be wound on a mandrel and moulded directly into the surface of the bore of the coupler during its moulding. |
