| 摘要 |
An optical cable having a bore in which is loosely housed two helically extending optical fibre ribbons and which is filled with a greasy water-impermeable medium is manufactured by feeding four flexible cords of electrically insulating material into circumferentially spaced, longitudinally extending grooves in the outer surface of a stationary rigid tubular elongate guide of circular cross-section, helically lapping two optical fibre ribbons around the guide and the flexible cords so that the cords support the helically lapped ribbons, applying longitudinally to and transversely folding around the guide and the optical fibre ribbon a flexible strip of electrically insulating material to form a tube, introducing water-impermeable medium in a liquid or semi-liquid state through a bore in the guide and into the tube and extruding around the tube a sheath of electrically insulating material. Preferably, at a position downstream of the position at which water-impermeable medium is introduced into the tube, the flexible cords are fed through a die downstream of and in axial alignment with the guide so that the cords will lie along the center of the filled tube and will not inhibit movement of the helically lapped optical fibre ribbons when the cable is flexed or stretched. |
