Patent GB-430992-A (GB)
Title: Improvements relating to trunk communication cable installations for the transmission of high frequency currents
IPC: H01B7/00
Filed: 1933-12-28
Abstract: 430,992. Cables. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Dec. 28, 1933, Nos. 39496, 39497, and 39499. Convention dates, Dec. 28, 1932, Feb. 17, 1933, and Nov. 28, 1933. [Class 36] A trunk communication cable installation arranged for high-frequency transmission has a cable of the installation comprising one or more double cores, the cores of which are each formed by at least one conductor of thin strip form and the conductors of the cores are arranged opposite to one another in such a manner that one of the wide surfaces extending between the longitudinal edges of a conductor of one core is presented towards a corresponding wide surface of a conductor of the other core. The cores may be surrounded by an open or closed conductive screen which is insulated or conductively connected with the cable-jacket or with earth. A number of double cores may be combined into one cable and be connected up to form phantom circuits ; each four cores may be combined together in the manner of the star or Dieselhorst-Martin stranding and may be suitably loaded. The cores may be rolled out into strips from round rods and the steps of rolling, insulating and stranding the cores may be effected in one continuous working operation. In Fig. 1 the cores are in the form of two flat strips ; they are preferably provided with air-space insulation 2 and are rounded at the corners. The cores may be of shallow circular segmental cross-section and may have their outer surfaces grooved. Each core may be subdivided into two or more individual conductors such as 6, 7, Fig. 3, the individual conductors appertaining to the respective cores, being diagonally opposite each other. The cores may be arcuate, Fig. 4, or they may be L- or U-shaped or substantially so ; in these cases they are separated by an insulating band 14, are held in place by insulating material 15, and are provided with a helically-wound cord 16, a paper layer 17 and a metal or insulating jacket 18. When the cores are arcuate they may be arranged so that their edges overlap. In another form, the strips may be constituted by a series of thin wires 31, Fig. 8, the strips being kept apart by insulating-cords 37 and being arranged about an air-spaced core 33 built up of a conducting or insulating core 35 and a helically-wound cord 36. In a further form, Fig. 10, an inner strip 180 preferably with its edges folded over is surrounded by paper insulation 181, return bands 182, 183 in the form of a sleeve of copper or a lead-jacket 184 or both. As an alternative to paper insulation, distance-pieces 185, 186, Fig. 11, may be arranged on cords 187 to give air-space insulation, or the pieces may be of U-form applied to the central band. The pieces may be composed of ceramic material or of polyvinyl compounds, preferably polystyrol. According to the Specification as open to inspection under Sect. 91, four conductors are wound into the form of a spiral quad and may be constituted by strips of rectangular, semicircular, triangular or L-shaped cross-section ; in the latter case, additional stranded conductors may be disposed in the angles. The conductors may be solid or stranded and coated with non-oxidizing material such as chromium or varnish. The four cores 101-104 may be braided as shown in Fig. 16 (Cancelled), a cord 105 being helically wound about them and further cords 106, 107 running in sinuous form about the cores and the cord 105. It is stated that these arrangements may be applied to core-groups of three, five, six and eight cores. This subject-matter does not appear in the Specification as accepted.