Electric cables

942,730. Electric cables. STANDARD TELEPHONES & CABLES Ltd. July 30, 1962, No. 29185/62. Heading H1A. To assist bending of electric cables of the type which includes a metal tube, the tube has two sets of corrugations which cross one another, one of the sets being longitudinal. As shown, Fig. 1, an insulated cable core 1 is supplied from drum 2 and an aluminium strip 3 polythene coated on one side from a reel 4. The strip is fed between rollers 22 which corrugate it longitudinally and transversely and then passes to a forming tool 5 where it is folded round the cable core and edges 6, 7 (Fig. 2), are bent away from the cable. Next these edges are sealed together by heated rollers 8, folded over to the position shown in Fig. 2, by rollers 11, 12 and fed by caterpillars 13, 15 to an intrusion machine 16 which provides a thermoplastic sheathing 17. The whole may be lapped with a thermoplastic tape prior to the extrusion of the outer thermoplastic sheath. A cord 30 may be provided for edges 6, 7 to be bent over. The aluminium strip may have a thermoplastic coating on its outside. One set of corrugations may be helical and the edges 6 and 7 may be sealed by a line weld or may merely lie on the cable with a gap between them. The circumferential corrugations may be deeper than the longitudinal ones.