Method of and an apparatus for producing an optical multi-fiber cable element
AssigneeNokia-Maillefer Holding S.A.
InventorsTeuvo Paivinen, Jouko Heikkila
Life of this patent
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Abstract
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.
Claims10
A method of producing an optical multi-fibre cable element provided with a secondary sheathing, comprising
- extruding (1) a loose secondary sheathing (10) around a fibre bundle (9) of several optical fibres (8);
- introducing a grease filling (2) into the secondary sheathing, said grease filling allowing the fibres to move axially with respect to each other within the secondary sheathing;
- providing the fibres with a desired extra length with respect to the secondary sheathing in a stretching device;
- and
- reeling a secondary-sheathed cable element (11) so obtained onto a receiving reel (4);
- the fibres being guided in such a manner that the position of the fibres varies continuously in the stretching device (3;
- 18) providing the extra length;
- characterized in that
- the secondary sheathing (10) together with its fibre bundle (9) is twisted (12) around its axis after the extrusion step (1) to vary the twisting position of the fibre bundle when the sheathing enters the stretching device (3;
- 18) providing the extra length;
- the fibre bundle being twisted to such an extent that the spiral paths of the fibres in the fibre bundle are equally long in the stretching device.
An apparatus for producing an optical multifibre cable element provided with a secondary sheathing, comprising
- an extruder (1) for extruding a secondary sheathing (10) loosely around a fibre bundle (9) of several optical fibres (8);
- means (2) for feeding a grease filling into the secondary sheathing,
- a stretching device (3;
- 18) for providing the fibres with a desired extra length with respect to the secondary sheathing;
- and
- transferring means (5;
- 15;
- 16) for passing the fibres into the stretching device in such a manner that the position of the fibres is varied continuously in the stretching device (3;
- 18);
- characterized in that the transferring means (5;
- 15;
- 16;
- 17) for the fibres (8) are formed by twisting means positioned after the extruder (1), said twisting means being arranged to twist the secondary sheathing (10) and the fibre bundle (9) within it around the axis of the sheathing in such a way that the fibre bundle enters the stretching device in a twisted state.
Dependencies are inferred from the claim text.