GB449582A - Improvements in and relating to trunk communication electric cables comprising one or more screened core groups - Google Patents

Abstract

449,582. Cables. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. April 9, 1935, No. 10989. Convention date, July 17, 1934. [Class 36] In a trunk communication cable comprising one or more screened core groups, such as pairs or quads, and more particularly a high frequency cable, the screens are constituted by a plurality of good conducting metal strips or wires which are stranded around each core group in the same direction as, and with the same pitch as, the cores of the group. Fig. 2 shows a cable having a single core group consisting of conductors 10, 11 each having an air space insulation formed by a helically wound insulating cord 13 and an insulating sheath 14. The conductors 10, 11 are formed as thin metal tubes each supported by an insulating cord 12. Insulating fillers 15 are laid up with the two cores and the core group thus formed is surrounded by an insulating sheath 16 which supports a closed screen 17 consisting of thin overlapping copper strips stranded around the sheath 16 in the same direction as, and with the same pitch as, the conductors 10, 11. The screen is protected by an insulating sheath 18 and a lead jacket 19. The fillers 15 and insulating sheath 16 may be omitted and the screen supported by a member, such as a wire, which is wound under the screen as an open helix around the core group. Similar constructions of cables containing four core groups are described. In modified constructions the screens consist of two superposed layers of strips, the strips of the outer layer covering gaps between the edges of adjacent strips of the inner layer ; or the strips may be arranged in superposed pairs of which the edges of each pair at one side are spread apart to provide a recess into which the other side edges of the adjacent pair of strips are inserted. In another arrangement, Fig. 8, the screen consists of alternating single strips 62 and pairs of superposed strips 63, 64. According to the Specification as open to inspection under Sect 91. the screen may comprise thin wide strips 70, Fig. 11 (Cancelled), between which are disposed thick wires 71. A strip 72 may be wound over the screen to prevent displacement of the wires 71. This subject-matter does not appear in the Specification as accepted.