Optical cable and sheath removing method

Patent metadata

Field	Value
Publication number	US-10775581-B2
Application number	US-201716465628-A
Country	US
Kind code	B2
Filing date	Nov 15, 2017
Priority date	Dec 1, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

An optical cable includes: an optical fiber unit where a plurality of optical fibers are wrapped with a wrapping tape; at least three tensile strength members disposed in parallel with and on an outer side of the optical fiber unit at intervals in a circumferential direction; and a sheath that coats the optical fiber unit and the tensile strength members and that is disposed between the optical fiber unit and the tensile strength members. An inner wall surface of the sheath formed between the optical fiber unit and the tensile strength members protrudes toward a cable center in comparison with an inner wall surface of the sheath where none of the tensile strength members are disposed. A portion of the wrapping tape disposed on the inner wall surface that protrudes toward the cable center is depressed toward the cable center.

First claim

The invention claimed is:

1. An optical cable comprising:
an optical fiber unit in which a plurality of optical fibers are wrapped with a wrapping tape;
three tensile strength members disposed in parallel with and on an outer side of the optical fiber unit at intervals in a circumferential direction; and
a sheath that coats the optical fiber unit and the tensile strength members and that is disposed between the optical fiber unit and the tensile strength members, wherein
an inner wall surface of the sheath formed between the optical fiber unit and the tensile strength members protrudes toward a cable center in comparison with an inner wall surface of the sheath where none of the tensile strength members are disposed, and
a portion of the wrapping tape disposed on the inner wall surface that protrudes toward the cable center is depressed toward the cable center.

2. The optical cable according to claim 1 , wherein the optical cable has exactly three tensile strength members.

3. The optical cable according to claim 1 , wherein a degree of depression H (%) is 20% or lower when:
an inner radius of the depressed portion of the wrapping tape is r,
an inner radius of a non-depressed portion of the wrapping tape is R, and
the degree of depression H (%) is H=(R—r)/R * 100.

4. The optical cable according to claim 1 , wherein a tangent line on an outer side of two adjacent ones of the tensile strength members is disposed on an outer side of the optical fiber unit.

5. The optical cable according to claim 1 , wherein part of the optical fiber unit is disposed on an outer side of a tangent line on an outer side of two adjacent ones of the tensile strength members.

6. A sheath removing method comprising:
causing a blade of a tool to contact a sheath of an optical cable so that the blade of the tool crosses a length direction of the optical cable; and
moving the tool in the length direction, wherein
the optical cable comprises:
the sheath;
an optical fiber unit in which a plurality of optical fibers are wrapped with a wrapping tape; and
three tensile strength members disposed in parallel with and on an outer side of the optical fiber unit at intervals in a circumferential direction, wherein
the sheath coats the optical fiber unit and the tensile strength members, and

while the tool is moved in the length direction, the blade of the tool is guided by the tensile strength members.

7. The sheath removing method according to claim 6 , wherein, in removing the sheath, the blade of the tool is in contact with two adjacent ones of the tensile strength members.

8. A sheath removing method comprising:
causing a blade of a tool to contact a sheath of an optical cable so that the blade of the tool crosses a length direction of the optical cable; and
moving the tool in the length direction, wherein
the optical cable comprises:
the sheath;
an optical fiber unit in which a plurality of optical fibers are wrapped with a wrapping tape; and
three tensile strength members disposed in parallel with and on an outer side of the optical fiber unit at intervals in a circumferential direction, wherein
the sheath coats the optical fiber unit and the tensile strength members, and

in removing the sheath with the tool, the wrapping tape is deformed to be depressed toward an inner side with the blade moving in the length direction.

9. The optical cable according to claim 1 , wherein the tensile strength members are arranged at equal intervals in the circumferential direction.

10. The sheath removing method according to claim 6 , wherein the tensile strength members are arranged at equal intervals in the circumferential direction.

Assignees

• Fujikura Ltd

Inventors

• Sato Shinnosuke
• Isaji Mizuki
• Tomikawa Kouji
• Osato Ken

Classifications

• G02B6/566 Primary

  Devices for opening or removing the mantle · 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

• G02B6/4432 Primary

  with fibre reinforcements · CPC title

• G02B6/4486

  Protective covering · CPC title

• G02B6/449

  Twisting · CPC title