GB632657A - Improvements in or relating to flexible sheathed electric cables and their manufacture - Google Patents

Abstract

632,657. Sheathing electric cables. STANDARD TELEPHONES & CABLES, Ltd., and PHEAZEY, J. R. Aug. 30, 1946, No. 26208. [Classes 83 (ii) and 83 (iv)] [Also in Group XXXVI] Uniting by fusion; brazing.-A flexible sheath for an electric cable of circular, oval, rectangular, polygonal or asymmetrical cross-section is made by continuously wrapping, strip, tape or braid about the cable or an equivalent mandrel and passing it through a high-frequency heating device to unite the strip into a continuous sheath. The strip 1, Fig. 1, is helically wound with lap or butt edges and is united by fusing the tape &c. if of metal or a solder or braze coating thereon. The processes may be carried out in air, vacuum or special atmosphere, and the solder is applied by plating, painting, spraying or in paste, strip or wire form, with or without flux. The tape may be coated by electro-plating, hot-dipping, &c., and soldercoated aluminium and its alloys may be used. Two tapes 1, 5, Fig. 2, may be consecutively applied with the same or opposite hands and united singly or simultaneously. More than two layers preferably are heated separately. The strips may have special mating or interlocking edges and be fluted or corrugated, or may be bent around the cable to form a longitudinal butt or lap joint (Figs. 4 and 5, not shown). In a modification, non-metallic strip is used, e.g. paper, polystyrene, polyvinylchloride, &c. metallized on both surfaces or on one surface or at the edges for butt and lapped joints or on one surface for inwardly or outwardly-flanged joints 6, Fig. 6, which are subsequently flattened down, 7, to the sheath surface. In a further modification, the sheath may be stationary and the induction means is moved relatively to it. In another form, a plain tube may be finished through a drawing die or may be corrugated after jointing. In another modification, metallic plastic tapes are interleaved or covered ' with metal layers. According to the Provisional Specification the process is applicable for making tubes, the strip is wound under tension, and a combination of layers with longitudinal and helical joints is used. Also, plastic or paper tube may be extruded and then sprayed with metal which is induction heated to form an impermeable tube. Powder metallurgy.-Further, a pair of concentric metallic or non-metallic tubes may have the interspace filled with metal powder induction heated to fuse and form a joint or an impermeable layer.