Method for on-site connection of cables with optical fibres

Claim 1

A method of on-site connection of two transmission cables comprising optical fibres, each cable having a protective armouring enclosing a central core formed with regularly-shaped grooves around its periphery, each groove having a fibre comprising a thin sheath of uniform thickness therein, the method being characterized in that it comprises the following steps: (a) the end of a first cable is bared over a given length, the thus-uncovered fibres are bent away from the core and provisionally secured on to a holder surrounding the cable; (b) after the fibres have been bent away from the core, the core is cut perpendicular to its axis and an at least partly grooved portion of a first extension core is rigidly secured thereto; (c) the fibres are bent back into the grooves in the said portion and rigidly secured therein; (d) the first extension core portion and the fibres which it bears are cut perpendicular to its axis; (e) the ends of the fibres are cleaned, polished if necessary and coated with a lubricant providing protection and continuity of index; (f) the same operations are performed on the end of a second cable using a second extension core portion such that its cut surface is exactly identical with the cut surface of the first extension core; (g) each of the central core and extension core portion assemblies is permanently secured to each other by a tubular securing means which holds them rigid; (h) the two cut surfaces are placed in contact, using position-locating means to ensure that they are in predetermined mutual angular position, and the two portions are mutually aligned by said position-locating means; and (i) the portions are placed against one another at a predetermined pressure, using clamping means.

Claim 2

A method of on-site connection of two transmission cables comprising optical fibres, each cable having a protective armouring enclosing a central core formed with regularly-shaped grooves around its periphery, each groove having a fibre comprising a thin sheath of uniform thickness therein, the method being characterized in that it comprises the following steps: (a) the end of a first cable is bared over a given length, the thus-uncovered fibres are bent away from the core and provisionally secured on to a holder surrounding the cable; (b) after the fibres have been bent away from the core, the core is cut perpendicular to its axis and an at least partly grooved portion of a first extension core is rigidly secured thereto; (c) the fibres are bent back into the grooves in the said portion and rigidly secured therein; (d) the first extension core portion and the fibres which it bears are cut perpendicular to its axis; (e) the ends of the fibres are cleaned, polished if necessary and coated with a lubricant providing protection and continuity of index; (f) the same operations are performed on the end of a second cable using a second extension core portion such that its cut surface is exactly identical with the cut surface of the first extension core; (g) each of the central core and extension core portion assemblies is permanently secured to each other by a tubular securing means which holds them rigid; (h) the two cut surfaces are placed in contact, using position-locating means to ensure that they are in predetermined mutual angular position, and the two portions are mutually aligned by said position-locating means; and (i) the portions are placed against one another at a predetermined pressure, using clamping means.