| 摘要 |
445,070. Cables and conductors. CONDUCTEUR ELECTRIQUE BLINDE INCOMBUSTIBLE, 30, Rue d'Astorg, Paris. May 28, 1935, No. 15561. Convention date, May 29, 1934. [Class 36] [See also Group XI] Cables and insulated conductors, such as resistance conductors for use in heating elements, of the kind comprising a conductor 1, Fig. 2, carried within a sheath 3 from which it is insulated by powdered magnesia or other material having electrical and physical properties similar to magnesia, are manufactured by filling the space between the conductor and the sheath with compressed blocks 2 of the powdered insulating material and then subjecting the cable or sheathed conductor to a lengthening treatment, such as drawing, or rolling, so that the insulating material is returned to its powdered form. The blocks may be of cylindrical form, having one or more passages to accommodate the conductor or conductors, and may be soaked in boric acid, or provided with thin metal or paper coatings 8, 9, Fig. 4, to maintain them in a coherent form pending the lengthening process. To prevent relative displacement, the blocks may have interengaging projections and recesses 10, as shown in Fig. 4. The cylindrical blocks may be divided by plane or helical surfaces into two or more part-blocks which fit together around the conductor. Fig. 6 shows a cable having cylindrical blocks similar to that shown in Fig. 4, the blocks being divided axially into part-blocks, such as 11, 12 and 13, which are secured in place by a braided sheath 14. |
