Optical fiber cable, and method and apparatus for manufacturing optical fiber cable

Patent metadata

Field	Value
Publication number	US-10114186-B2
Application number	US-201615511369-A
Country	US
Kind code	B2
Filing date	Aug 12, 2016
Priority date	Sep 18, 2015
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

An optical fiber cable includes a core including a plurality of units which are assembled and each of which comprises a plurality of optical fibers which are assembled, a pair of tension members disposed so as to face each other with the core interposed therebetween, and a sheath covering the core and the pair of tension members collectively. The units are twisted so as to form a plurality of layers. The plurality of layers includes a first layer having first-layer units formed in an SZ-twisted shape and a second layer having second-layer units formed in an SZ-twisted shape. A twisting direction of the first-layer units is opposite to a twisting direction of the second-layer units in at least a portion in a cable length direction.

First claim

What is claimed is:

1. An optical fiber cable comprising:
a core comprising a plurality of units which are assembled and are twisted so as to form a plurality of layers, each of which comprises a plurality of optical fibers which are assembled, and which comprises a plurality of first-layer units and a plurality of second-layer units;
a pair of tension members disposed so as to face each other with the core interposed therebetween; and
a sheath covering the core and the pair of tension members collectively, wherein:
the plurality of layers comprises a first layer comprising the first-layer units formed in an SZ-twisted shape and a second layer covering the first layer and comprising the second-layer units formed in an SZ-twisted shape;
the first layer is arranged at a center portion of the core; and
a twisting direction of the first-layer units is opposite to a twisting direction of the second-layer units in at least a portion in a cable length direction.

2. The optical fiber cable according to claim 1 , wherein a twisting angle of the first-layer units and a twisting angle of the second-layer units satisfy the following Expression (1):
Twisting angle of second-layer units−Twisting angle of first-layer units≤120°  (1).

3. The optical fiber cable according to claim 2 , wherein the twisting angle of the first-layer units is larger than the twisting angle of the second-layer units.

4. The optical fiber cable according to claim 1 , wherein each of the twisting angles of the first-layer units and the second-layer units is 180° or more.

5. A method of manufacturing the optical fiber cable according to claim 1 using a fiber distributing board comprising a plurality of fiber distributing portions, wherein:
the plurality of fiber distributing portions comprises a first fiber distributing portion comprising a first unit insertion portion into which the first-layer units are inserted and a second fiber distributing portion comprising a second unit insertion portion into which the second-layer units are inserted;
the first-layer units are inserted into the first unit insertion portion and the second-layer units are inserted into the second unit insertion portion;
while the first-layer units and the second-layer units are received, the first fiber distributing portion and the second fiber distributing portion are rotated independently in a cable shaft rotation direction to twist the first-layer units and the second-layer units;
during the rotation, the first fiber distributing portion and the second fiber distributing portion are rotated such that a twisting direction of the first-layer units is opposite to a twisting direction of the second-layer units to form the core; and
the sheath is formed so as to cover the core and the pair of tension members collectively.

6. An apparatus for manufacturing the optical fiber cable according to claim 1 , comprising a fiber distributing board comprising a plurality of fiber distributing portions, an assembling mechanism which twists and assembles the first-layer units and the second-layer units, and a sheath forming apparatus which forms the sheath, wherein:
the plurality of fiber distributing portions comprise a first fiber distributing portion comprising a first unit insertion portion into which the first-layer units are inserted and a second fiber distributing portion comprising a second unit insertion portion into which the second-layer units are inserted; and
the first fiber distributing portion and the second fiber distributing portion can be rotated independently in a cable shaft rotation direction.

7. An optical fiber cable comprising:
a core comprising a plurality of units which are assembled and are twisted so as to form a plurality of layers, each of which comprises a plurality of optical fibers which are assembled, and which comprises a plurality of first-layer units and a plurality of second-layer units;
a pair of tension members disposed so as to face each other with the core interposed therebetween; and
a sheath covering the core and the pair of tension members collectively, wherein:
the pair of tension members is embedded in the sheath;
the plurality of layers comprises a first layer comprising the first-layer units formed in an SZ-twisted shape and a second layer covering the first layer and comprising the second-layer units formed in an SZ-twisted shape;
the first layer is arranged at a center portion of the core; and
a twisting direction of the first-layer units is opposite to a twisting direction of the second-layer units in at least a portion in a cable length direction.

Assignees

• Fujikura Ltd

Inventors

• Ito Naoto
• Osato Ken
• Yamanaka Masayoshi
• Okada Naoki

Classifications

• G02B6/4432 Primary

  with fibre reinforcements · CPC title

• G02B6/44

  Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables (cables incorporating electric conductors and optical fibres {where features relating to the optical fibres are not of interest} H01B11/22) · CPC title

• G02B6/449

  Twisting · CPC title

• G02B6/4413 Primary

  Helical structure · CPC title