GB461239A - Improvements in or relating to end fittings or joint fittings for electric cables having compressed mineral powder insulation - Google Patents

Abstract

461,239. Cable-end fittings; couplings. CONDUCTEUR ELECTRIQUE BLINDE INCOMBUSTIBLE. Aug. 7, 1935, No. 22324. Convention date, Aug. 8, 1934. [Classes 36 and 38 (i)] An end fitting for a cable having a conductor separated from a surrounding sheath by compressed mineral powder insulation, such as magnesia, comprises an insulating plug fitting within the end of the cable sheath and having a conical portion engaging in the insulation of the cable and a bore through which the conductor passes, and a sleeve which is swaged, welded or otherwise attached to the sheath and holds the plug in position against the end of the cable insulation, the connection of'the sleeve both to the plug and to the sheath being substantially fluid-tight. As shown, the conical part 2 of a plug 1, Fig. 1, e.g. of porcelain, engages a recess in the cable insulation 4, and a metal sleeve 8 connected fluid tightly to the plug is secured by swaging or welding to the cable sheath 6. A metal tube 13 fixed in the plug contacts with the conductor 5 whereby it may serve as a terminal. The tube 13 is closed by welding, or swaging to ensure fluidtightness. Iri the embodiment shown in Fig. 2, the cable conductor passes through the metal tube 13 which is swaged at 13<1> over the conductor and the metal sleeve 8 is corrugated at 12 for resiliency. In modified constructions, the end of the conductor is screw-threaded and a fluid-tight connection between the conductor and the plug is obtained by compressing packing between the end of the plug and a nut which is screwed on the conductor. When the plug and sleeve are separately formed the latter may screw on the end of the cable sheath and be provided with an inwardly directed flange which engage, with the interposition of packing, a shoulder on the plug. Fig. 5 shows the cable conductor 5 joined to another conductor 5<1> by extending the metal tube 13 and swaging, welding or otherwise securing it to both conductors. A joint between two similar cables 5, 6, 5<1>, 61 is formed by fitting double-coned insulating plugs 15, 15<1> to each cable and fitting the cable ends into a metal sleeve 16, Fig. 7, which is welded, brazed &c., to the sheaths 6, 6<1> the conductors 5, 51 frictionally engaging a metal tube 17 insulated from the sleeve 16 at 18.