GB1153152A - Telephone Cable Sheath - Google Patents

Abstract

1,153,152. Cables. GENERAL CABLE CORP. 20 June, 1966 [13 Sept., 1965], No. 27352/66. Heading H1A. A telephone cable comprises a core consisting of stranded paper insulated conductors 10 bound with paper tape 12, an inner jacket 14 formed by lengthwise wrapping a metal tape coated on at least the eventual inside surface with plastics material chemically bonded to the metal, the edges being joined together as shown at 6-6, and an outer jacket 34 formed by lengthwise wrapping a metal tape coated on both sides with plastics material, the edges overlapping as shown at 7-7. A plastics outer sheath 42 is bonded to the plastics material on the outside of jacket 34. The two composite jackets may be applied continuously to the core (Fig. 1, not shown). The inner jacket 14 is preferably formed from thin metal foil coated on the eventual inside surface with a polyethylene which incorporates carboxyl groups and on the other surface with a material of higher softening point, e.g. polyethylene terephthalate, polypropylene or high density polyethylene, to prevent the outside of jacket 14 bonding to the inside surface of jacket 34. As jacket 14 is wrapped round the core, the abutting inside edge portions are softened with hot gas (Fig. 3, not shown), pressed together (Fig. 4, not shown) and folded over. Jacket 34 is formed from relatively thick metal coated on both sides with preferably the same carboxyl-containing polyethylene as the inside of jacket 14. Metal to plastics ratio in jacket 34 may be about 2 to 1 as compared with about 1 to 8 in jacket 14. The metal may be aluminium, copper or steel, a steel layer also providing magnetic shielding. Outer jacket 42 is preferably polyethylene.