GB1007939A - Coaxial cable and production thereof - Google Patents

Abstract

1,007,939. Cables. FUJIKURA DENSEN KABUSHIKI KAISHA. July 20, 1962 [July 21, 1961; March 14, 1962], No. 28049/62. Heading H1A. In a coaxial cable the space between the concentric conductors is filled with an insulating layer of foamed synthetic resin having a film layer of synthetic resin of low melting point intimately cohering with its outer surface. The insulating separator material may be foamed polystyrene and the film layer may be of polyethylene. A process of manufacture is described (Fig. 4) in which a synthetic resin tape of low melting point 6 is coated with an adhesive 7 and is then covered with a layer of unfoamed or incompletely foamed synthetic resin chips 8, the assembly together with an inner conductor 9 and accompanied by part of an endless forming tape 14, e.g. of P.T.F.E., then proceeds through a forming die 11 in which the cable core is formed into a concentric construction prior to entry into a heater 13 in which the resin chips are foamed and the synthetic resin tape 6 is adhesively secured to the surface of the foamed resin. The tape 14 then separates off and the cable, core so formed may then proceed to a series of repeat operations (Fig. 5, not shown), wherein the core takes the place of the inner conductor in the assembly process and an outer concentric conductor which may be of copper tape is applied, to form a cable of larger diameter. Instead of synthetic resin chips in the unfoamed state, foamed synthetic resin sheet material may be employed (Figs 6 and 7, not shown), and it is also proposed that a copper tape, which ultimately is retained as the outer conductor, should take the place of the separate forming tape 14.