GB908848A - Improvements in or relating to communication cables - Google Patents

Abstract

908,848. Cables. SIEMENS & HALSKE A.G. Dec. 30, 1960 [Dec. 31, 1959], No. 44765/60. Class 36. In communications cables having at least one layer of individual wires, the wires are stranded around a core of high tensile strength and systematically crossed at intervals. The cable shown in Fig. 5 has a steel wire core 95 surrounded by an insulating layer 96 of a synthetic thermoplastic such as P.V.C. or polythene. The eight insulated conductors, systematically crossed to form four pairs in the manner described in Specification 878,062, are laid on this core and are each provided with an abrasionresistant layer 101, e.g. of polyamide material. Similar cables are described with reference to Figs. 1 and 3 (not shown), the cables being without the abrasion-resistant sheaths 101, and additionally that of Fig. 3 (not shown) has the insulatinglayer 96 replaced by an inner layer of a mixture of a thermoplastic material and a fine magnetizable powder such as a ferrite, and a surrounding layer of P.V.C. or polythene. In the submarine cable of Fig. 6 a stranded steel core 97 is surrounded by an insulating layer of P.V.C. or polythene upon which the conductors are laid. The shroud 102 is of a non-hygroscopic material such as polythene, and the spaces between the core and conductors are filled with a plastic mass based on polythene or polyisobutylenes mixed with mineral oils or waxes. The cable of Fig. 2 (not shown), is of similar construction but lacks the shroud and the material between the core and conductors. This unshrouded construction also forms the centre of the two conductor-layer cable of Fig. 4 (not shown), a separating layer of conductive or non-conductive material being applied before the laying of the sixteen individually insulated outer conductors. The transportable telecommunications cable of Fig. 7 has a stranded steel core 97 surrounded by a magnetizable layer 104, which may be extruded from a mixture of a thermoplastic and a finely-divided ferrite, the insulated conductors being laid on this core and surrounded by a further magnetizable layer 105 which is covered with high tensile strength steel wire netting 106 lying immediately beneath the protective P.V.C. sheath 107. The wire netting may be omitted and the magnetizable layers replaced by insulating layers, an electrostatic screen, e.g. of graphite impregnated textile tape may then be provided between layer 105 and the sheath. In all embodiments the high tensile core may be of single or stranded steel wire, or of a non-conductive material such as a polyamide.