GB492158A - Improvements in electric cables - Google Patents

Abstract

492,158. Cables. OKONITE CO. Jan. 15, 1937, No. 1317. Convention date, Jan. 15, 1936. [Class 36] A cable comprises a core of extensible but substantially volumetrically incompressible material and a conductor applied helically about the core and in contact therewith with a lay substantially in accordance with the formula where L is the lay of the conductor, d0 the core diameter, and d the conductor diameter. A variation in the lay of 25 per cent from the calculated value is permissible. Such cable may comprise a conductor formed of parallel strands 2, Fig. 1, applied about a core 1 of rubber or twisted silk or cotton threads and surrounded by rubber or rubber compound insulation 3, a fabric covering 4, which may be saturated with Harvel, and an armouring 5 of stranded steel. The conductor may, in other forms, comprise twisted strands, a continuous strip or tape or a woven or braided tape : in the case of a strip or tape, the thickness is regarded as the diameter d. In other forms, the cable comprises a plurality of single conductor cables 10, Fig. 11, each as shown in Fig. 1, assembled around a core 11 of hemp, or two similar but unarmoured single conductor cables 12, Fig. 12, twisted together, embedded in jute 13 and surrounded by tape and a plurality of single conductor cables therearound.