JP2001066482A - Optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability in drawing out coated optical fiber tapes by facilitating the separation of tape core wires from cord bodies in an intermediate branching operation. SOLUTION: A laminate of coated optical fiber tapes which is prepared so that a plurality of laminated tapes 1 obtained by arranging plural optical fibers in parallel and integrating them with resin, is twisted at a prescribed pitch and then covered with plural cord bodies 2 by winding the laminate on the outer circumference. Its further outer side is formed with a jacket 3 in which tensile bodies 4 are embedded. In an optical fiber cable so structured, the winding direction of the cord bodies 2 is reversed to the twisting direction of the laminate of the tapes, so that the cord bodies 2 are prevented from entering between the tapes 1 comprising the laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable using a ribbon.

[0002]

2. Description of the Related Art A loose tube structure is one of the basic structures of an optical fiber cable. In this method, an optical fiber core wire or a tape core wire is accommodated in a tube made of plastic such as polybutylene terephthalate or polypropylene, and a gap is filled with a gel filler such as jelly. As a cable having a loose tube structure, as shown in FIG. 4A, a plurality of tubes 6 containing optical fibers 7 are assembled around a central tensile strength member 5, and as shown in FIG. In addition, there is a central core type having a loose tube portion in the center of the cable and in which a laminated body of the tape cores 1 is stored.

[0003] The tape core is formed by arranging a plurality of, for example, four, optical fibers in parallel, and integrating them with resin to form a tape. Since such a tape core can take a free state in a completely free space, each optical fiber does not bend locally and there is almost no increase in transmission loss. However, if multiple tape cores are placed in a closed space, the movements of the tape cores that occur with the change in the closed space are obstructed by each other, making it impossible for some tape cores. A gentle bending increases transmission loss.

Therefore, in a conventional optical fiber cable using a tape core, an aggregate is formed by laminating two or more tape cores, so that the behavior directions of the respective tape cores are made substantially the same, and the Only the tape core of the section is prevented from being hindered from moving. In the above-mentioned central core type optical fiber cable, such a tape core laminate is housed in a loose tube, the gap is filled with jelly 8, and the sheaths 3 together with the tensile strength members 4, 4 are placed thereon. Is formed. Then, by appropriately adjusting the viscosity of the jelly 8, even if an external force such as pulling or bending is applied to the cable, the tape core wire 1 moves in the tube and the stress applied to the optical fiber can be reduced. .

As described above, the optical fiber cable having the loose tube structure has excellent characteristics, but has a disadvantage that workability at the time of connection is poor. That is, when connecting the cable,
The work of wiping the jelly 8 is required. At that time, it is necessary to work carefully so as not to damage or break the tape 1 or the optical fiber therein, which takes time.

In view of the above, we have previously disclosed in Japanese Patent Application No. 10-116230 an optical fiber in which an optical fiber is protected by arranging a string instead of jelly 8 around a tape core laminate. Suggested cable. In the cable, the tape core laminate was further twisted around its central axis so that each tape core of the tape core laminate was restrained, and the stacking collapse was reduced. Also, when pulling out the tape core wire at the middle part of the cable at the time of connecting the cable, the extra length of the cord can be taken large, and a gap occurs between the tape core laminate and the cord. In order to facilitate the work, the cord was twisted and arranged around the outer periphery of the tape core laminate. As a result, an optical fiber cable with good workability at the time of cable connection was realized while suppressing costs.

[0007]

However, in such an optical fiber cable, a cord is disposed around the tape core laminate. Therefore, when removing the jacket of the cable and taking out the tape core wire during the intermediate branching operation, the cord enters the space between the cords of the tape core laminate, and the cord and the tape core laminate are inserted. And are integrated,
There was a problem that it was difficult to take out the tape core.

SUMMARY OF THE INVENTION The object of the present invention is to solve such a problem and to improve the workability by facilitating the separation of the tape from the cord during the intermediate branching operation. It is.

[0009]

In order to solve the above-mentioned problems, an optical fiber cable according to the present invention comprises a plurality of optical fiber fibers arranged in parallel, and a plurality of optical fiber ribbons laminated by a resin. Twisting the laminate at a predetermined pitch, covering the tape core laminate by twisting a plurality of cords from the outer periphery thereof, in an optical fiber cable having a jacket formed on the outside thereof, The twisting direction is opposite to the twisting direction of the tape core laminate. This facilitates separation and removal of the tape from the cord during the intermediate branching operation, thereby improving workability.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of one embodiment of the present invention. In FIG. 1, 1 is a tape core, 2
Is a string, 3 is a jacket, and 4 is a tensile member.

The tape core 1 is formed in a tape shape by embedding and integrating four optical fibers arranged in parallel in a resin. Cover the entire outer periphery of the tape core laminate in which six such tape cores 1, 1, ... are laminated with a plurality of cords 2 continuous in the longitudinal direction, and cover the outside thereof. The tensile strength members 4 and 4 are integrally covered with an embedded jacket 3.

In the present invention, as described above, each tape core 1
Are laminated to form an aggregate, the behavior directions of the respective tape cores 1 are made substantially the same, and the movement of only a part of the tape cores 1 is prevented from being hindered. Further, FIG.
As shown in (a), by twisting the tape core laminate around the central axis thereof, each tape core 1 of the tape core laminate is restrained, and stacking collapse is reduced. .

In addition, by simultaneously covering and holding the tape core laminate from the outside with the cord 2, the individual movement of each tape core 1 is suppressed,
The bend caused by local buckling on some of the tape cores 1 is suppressed.

The cord 2 is formed in a cord shape using a fibrous body made of plastic or the like, and may be a twisted one such as a thread or a non-twisted one. As shown in FIG. 2B, the cord 2 is arranged around the outer periphery of the tape core laminate so as to be twisted in a direction opposite to the twisting direction of the tape core laminate. As described above, when the cord 2 is twisted around the outer periphery of the tape core laminate in the direction opposite to the twisting direction of the tape core laminate, the cord 2 crosses the tape core 1. Become. As a result, the cord 2 does not enter between the cords of the tape core laminate, the separation of the tape 1 and the cord 2 becomes easy, and the operation of pulling out the tape 1 is performed manually. Can be done easily.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Standard 4 having a thickness of 0.3 mm and a width of 1.1 mm
Six cored ribbons were laminated to form a laminated tape core. After twisting at a pitch of 400 mm around the center line of the laminated body as an axis, a 50
Twenty 00 denier polypropylene yarns were twisted in a direction opposite to the twisting direction of the laminate to form a cable core. Then, on both sides of the cable core, two steel wires of 1.2 mm as tensile strength members 4 and 4 were arranged in parallel, and integrated with a jacket 3 made of polyethylene to form an optical fiber cable.

On the other hand, as a comparative example, as shown in FIG. 2C, an optical fiber cable having the same configuration except that the twisting direction of the cord 2 is set to the same direction as the twisting direction of the laminate. Formed. Then, in the middle part of the optical fiber cables of the example and the comparative example, as shown in FIG. This work is done by one person,
The experiment was performed on 10 workers, and the average working time of 10 times was obtained for each cable. as a result,
In the comparative example, the average operation time for 10 operations was 462 seconds, whereas in the above example, the average operation time for 10 operations was significantly reduced to 300 seconds.

By the way, when the cord 2 is twisted in a direction opposite to the twisting direction of the tape core laminate to form a cable core, the cord 2 crosses the tape core 1. Therefore, there is a possibility that the tape core wire 1 is locally bent by each of the cords 2 and transmission loss of the optical fiber increases. About that point, it can be eased by making the thickness of each cord-like body 2 thin, and it is easy to separate the tape core wire and the cord-like body during the intermediate branching operation, and to improve the workability. And maintaining a low transmission loss.

[0018]

As described above, in the optical fiber cable according to the present invention, the twisting direction of the cord is set to the opposite direction to the twisting direction of the tape core laminate, so that It does not enter between the core wires of the tape core laminate. As a result, at the time of the intermediate branching operation, the separation of the tape core wire and the cord-like body is facilitated, and the workability of drawing out the tape core wire is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention.

FIG. 2 is a diagram illustrating a twisted state of a tape core laminated body and a twisted state of a cord-like body.

FIG. 3 is a diagram showing a jacket removal portion during an intermediate branching operation.

FIG. 4 is a sectional view of a conventional optical fiber cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tape core wire 2 ... String-shaped body 3 ... Jacket 4 ... Tensile body 5 ... Center tensile strength body 6 ... Tube 7 ... Optical fiber 8 ... Jerry 9 ... Jacket

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Daisuke Iwakura 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Masato Takasaka 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Hideyuki Iwata 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation F-term (reference) 2H001 BB16 BB23 DD06 DD09 KK06 KK17

Claims (1)

[Claims] 1. A tape core laminate in which a plurality of optical fibers arranged in parallel are integrated with a resin by laminating a plurality of tape cores is twisted at a predetermined pitch, and a plurality of cords are wound from the outer periphery thereof. In the optical fiber cable in which the sheath is formed by covering the tape core laminate by twisting, the twisting direction of the cord is opposite to the twisting direction of the tape core laminate. An optical fiber cable characterized in that: