Nokia-maillefer Holding S.a.

Jouko Heikkila

Teuvo Paivinen

A method of producing an optical multi-fibre cable element provided with a secondary sheathing by extruding (1) a loose secondary sheathing (10) around a fibre bundle (9) and providing the fibres with a desired extra length with respect to the secondary sheathing. To avoid variation in fibre length in the production of cable elements the secondary sheathing (10) together with the fibre bundle (9) is twisted (12) around its axis after the extrusion step (1) at least to such an extent that the longitudinal sliding of the fibres with respect to each other is prevented in the twisted fibre bundle and that the stretching of the fibres in the fibre bundle at the step of providing the extra length (3; 18) is kept within the elastic range of the fibres. In an apparatus suitable for realizing the method, twisting means (7) are provided after the extruder and before the device providing the extra length, which twisting means twist the secondary sheathing and the fibre bundle in such way that the fibres are locked together.

Method of and apparatus for producing an optical multi-fibre cable

A method and apparatus for producing an optical multi-fiber cable element provided with a second sheathing by extruding a loose secondary sheathing around a fiber bundle and stretching the fibers a desired extra length with respect to the sheathing, the fibers being guided in such a manner that the position of the fibers varies continuously during stretching. To produce an untwisted cable element and avoid variation in the fiber length, the secondary sheathing together with its fiber bundle is twisted around its axis after the extrusion or the sheathing to vary the twisting position of the fiber bundle as the sheathing and fibers approach the stretching step.

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Helsinki, Finland

Jouko Heikkila