GB500074A - Improvements in and relating to electric cable sheathings - Google Patents

Abstract

500,074. Cables. WOLFER, F. Jan. 10, 1938, No. 749. Convention date, Jan. 9, 1937. [Class 36] A watertight cable sheath comprises two or more layers 3, 4, 5 of flexible metal band windings and intervening waterproof sealing layers 6, 7, the metal bands being wound helically in the same direction in open, abutting or overlapping turns, one metal band winding 3 being in direct contact with the insulation 2 and the metal band winding of each other layer covering the gap, butt joint or overlap of the winding of the layer immediately beneath it, and the sealing layers being in watertight contact with the windings on either side thereof. Preferably, the waterproof sealing layers 6, 7 form a closed covering between the layers 3, 4, 5. The metal bands are provided with central grooves or corrugations 9 lying opposite the gaps of the next layers and grooves 10 are provided for engagement of the bands of adjacent layers. The sealing layers may be of metal, e.g. lead or solder, or of a non-metallic material, e.g. asphalt, asphalted paper, layers of paper and compound polyvinyl chloride or a polymerized acrylic acid ester; for instance, the layer 6 may be of polyvinyl chloride and the layer 7 of asphalted paper. The windings 3, 4, 5 may be of aluminium, iron or steel or they may be covered with or provided as a deposit on paper or artificial resin.