JPS63200105A - Structure body for optical fiber cable branch part - Google Patents

Abstract

PURPOSE:To eliminate an influence of the variation of temperature of outside air upon an optical fiber core by providing a hollow case body, which has branch tube parts to guide branch fibers to the outside, and a cover member which consists of an admixture and hermetically covers the case body from the outside. CONSTITUTION:A hollow case body 5 where branch tube parts 10 and 10 which project branch fibers F to the outside are formed and a cover member 37 which hermetically covers the case body 5 from the outside are provided. The cover member 37 consists of an admixture like a polyurethane resin and is broken with a slight external force. Consequently, optical fiber cores or optical fiber units 3 exposed from the coating end part of a sheath in prescribed positions (namely, branch parts) of the cable are coated with the hollow case body 5, and the case body 5 is covered with the cover member 37. Thus, the variation of temperature of outside air is not transmitted to optical fiber cores or optical fiber units.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical fiber cable branch structure.

[Conventional technology and its problems]

Generally, when branching an optical fiber cable or an optical fiber unit of an optical fiber cable that includes a plurality of optical fiber cables or optical fiber units within a sheath,
After exposing the optical fiber or the optical fiber unit from the sheath and taking out the optical fiber or the branched fiber of the optical fiber unit, the sheath was sealed from the outside.

However, in this case, if the temperature changes rapidly in the vicinity of this branch, it will have an adverse effect on the optical fiber core or the optical fiber unit at this branch.

Therefore, it is an object of the present invention to provide an optical fiber cable branch structure that does not have any effect on the optical fiber core even when the temperature changes in the outside air.

[Means for solving problems]

The optical fiber cable branching structure of the present invention has a sheath that includes a plurality of optical fiber cores or optical fiber units. A branching part structure for branching; which coats the optical fiber coated wire or the optical fiber unit exposed from the coated end of the sheath at a predetermined portion of the cable; It consists of a hollow case body with a branch pipe section that guides and guides the branch fiber to the outside; and a mixture of polyurethane resin and the like that can be crushed by a slight external force.
and a covering member for sealingly covering the case body from the outer surface.

[Effect]

If configured as described above, the predetermined portion of the cable (that is,
The optical fiber core wire or optical fiber unit exposed from the coated end of the sheath at the branch point) is covered by a hollow case body, and the case body is covered by a coating member, and the optical fiber core or optical fiber unit exposed from the coated end of the sheath at Temperature changes in the outside air are not transmitted to the optical fiber core or optical fiber unit, and the coating member is made of a mixture that can be crushed by a slight external force.
The case body can be easily taken out from the covering member.

〔Example〕

Hereinafter, the present invention will be explained in detail based on drawings showing examples.

1 and 2, 1 indicates a branch fiber F of an optical fiber unit 3 of an optical fiber cable 4 which includes a plurality of optical fiber units 3 within a sheath 2.
A hollow case main body 5 is an optical fiber cable branching structure for branching out of the sheath 2, and has a branch pipe section 10.10 for protruding the branched fiber F to the outside.
and a covering member 37 for sealingly covering the case body 5 from the outside.

Thus, the case main body 5 is made of a cylindrical body having a reduced diameter at both ends 6.7 and two branch pipe parts 10.10, and the ends 6, 7 have recesses, respectively. A groove 11.12 is formed, and the tips of the ends 6.7 are each formed with a tapered surface 13.14.

Specifically, the case main body 5 has a pair of halves, each of which includes a main body groove 15 having a substantially semicircular cross section, and a branch groove 16.16 having a substantially semicircular cross section connected from the main body groove 15. split body 5a,
It consists of 5a and is divisible.

Further, the branch grooves 16.16 are bifurcated from the main body groove 15, and the angle α between the axial direction of the branch grooves and the longitudinal direction of the cable 4 is a predetermined obtuse angle. and,
An outer flange 17 is formed on the opening edge excluding both ends of the main body groove 15 and the tip of the branch groove 16, and a back surface 17 of the outer flange 17
Open end surfaces 18, 19, and 20 at both ends of the main groove 15 and the tip of the branch ti 16.1B are used as mating surfaces 21. Further, a pair of half-ring bodies 31, 31 are formed in each of the branch grooves 16.

And between the mating surfaces 21 and 21 of the half bodies 5a, 5a,
The outer half body 5a is interposed with a packing made of rubber, synthetic resin, etc.
5a, and apply a backing plate 25 to the surface 1'7b of the outer flange 17 of one half body 5a, and fix the fixing device 23 such as a screw.
is inserted into the through hole provided in the outer flange 17 to remove the half body 5.
a and 5a are fixed to each other to form an integral body. Then, with the overlapping branch grooves 16.16, the branch pipe portion 10.1
0 is formed. In this embodiment, the fixing tool 23 uses a screw and a nut, and the nut is attached to the other half body 5a.
It is embedded in the through hole.

Therefore, a cap 8.8 having an insertion hole 28 through which the cable sheath 2 is inserted is installed inside the end portions 6, 7 of the case body 5, and when the case body 5 is integrated. , the case body 5 is held on the cable. That is, this cap 8 consists of a short cylindrical body, and the outer peripheral surface 26
, a concave circumferential groove 11 formed in the end portion 6.7 of the case body 5.
．． A concave circumferential groove 50 and a tapered surface 29 corresponding to the tapered surface 12 and the tapered surface 13, 14 are formed. Furthermore, a tapered surface 30 is also formed on the proximal outer circumferential surface 26. Further, in this embodiment, the cap 8 is formed by combining a pair of halves, and is set so that the sheath 2 can be easily inserted into the insertion hole 28. In this case, it is preferable that the cap 8 is not made into a pair of halves, but instead is made into an integral piece with a slit portion formed therein so that the insertion hole 28 is expanded. Furthermore, when forming the slit portion, it is preferable to form it in a straight line shape or in a bias shape.

Then, the coated ends 2a, 2a of the sheath 2 of the optical fiber cable 4 are inserted into the cap 8.8 configured as described above, and the cap 8.8 is inserted into the end 6 of the case body.
, 7, the half bodies 5a and 5a are put together, and the cough half bodies 5a+5a are integrated as described above, and the grooves 11 and 12 of the case body 5 are respectively tightened. When the band 9.9 is fitted and tightened, the inner circumferential surface 27 of the case body 5, the outer circumferential surface 26 of the cap 8, and the cap 8 inner peripheral surface 32
and the outer peripheral surface 33 of the covered end 2a of the sheath 2 are in close contact with each other, and the case body 5 is attached to a predetermined portion of the cable.

The branch pipe portions 10.10 are connected with protective tubes 36 into which the branched fibers N are respectively inserted.

That is, this protection tube 36 is made of a metallic flexible tube (i.e. gold J7J).
f! If the tube is pulled, the inner diameter will be reduced, and if it is compressed, the inner diameter will be enlarged. A connector 35 made of a cylindrical body having an outer flange 34 at the base end is interposed between the half-ring body parts 31 and 31 of the branch groove 16.
A protective tube 36 is inserted and fixed at the tip of the tube 5. That is, if the protective tube 36 in a contracted state is inserted into the tip of the connector 35 and then pulled, the inner diameter of the protective tube 36 will be reduced, and the protective tube 36 will be inserted into the connector 35. Fixed.

In addition, in the case where the
It is also preferable to wrap a seal ring tape such as PvC tape or butyl rubber tape around the proximal end of the branch pipe 10 to seal the proximal end of the protective tube 36 .

Further, as shown in FIG. 5, the optical fiber unit 3 used in the example includes a coating layer 39, a tension member 40 included in the coating layer 39, and six optical fiber core wires 48.
It consists of... In this case, of course, the number of optical fibers 48 is free.

The covering member 37 covers the entire case body 5, is made of a mixture of polyurethane resin, etc., and is crushed by a slight external force. In this case, of course,
The covered end portions 2a, 2a of the sheath 2 and the branched fiber protection tube 36°36 are inserted into the covering member 37 through the insertion hole 38.
．． 43 is formed.

Therefore, if formed as described above, the covering member 37 can be easily disassembled with fingers or the like, and the case body 5 can be taken out from the covering member 37.

Next, FIG. 4 sequentially shows the branching method when this branching part structure 1 is used. First, as shown in FIG. The optical fiber unit 3... is exposed from the
As shown in the figure, the optical fiber units 3 are exposed by a predetermined dimension at two separate parts separated from a predetermined part. Then, as shown in FIG. 4 (■), the optical fiber unit 3 to be branched is cut at separate locations to form branched fibers F, F, and further, the branched fibers F, F are pulled out from predetermined locations. In this state, this branch structure 1 is attached. That is, the cap 8°8 with the covered end 2a of the sheath 2 inserted through the insertion hole 28 is fitted to both ends of the half body 5a, and the connector 35 into which the proximal end of the protective tube 36 is inserted and fixed is inserted. The outer flange 34 of the ring body 31.31
The branch fiber F from below is inserted into the upper protection tube 36 via the connector 35 of the upper branch groove 16, and the branch fiber F from above is inserted into the upper branch groove 16. After passing through the lower protection tube 36 via the tool 35, the half-split bodies 5a, 5a are integrated. Then, the case body 5 is covered with the covering member 37. Further, in each separated part, there is a structure 4 having the same structure as the branch part structure 1 except that the case body 41 does not have the branch pipe 10.10.
2 is attached, and the branching work is completed.

Therefore, according to the above-described embodiment, the branch fibers F, F protruding from the branch pipe portion 10°10 are slightly curved, and are bent at an angle α forming a predetermined obtuse angle with the longitudinal direction of the cable 4. The bending radius of this branched fiber F becomes large, and the branched fiber F is protruded from the main body 5.
does not bend sharply. Note that this angle α is set to such an angle that the bending radius when the optical fiber unit 3, which is the branched fiber F, is bent does not become smaller than the allowable bending radius of the unit 3. In other words, the unit 3 is set so as not to bend beyond the allowable bending radius.

In addition, the caps 8.8 with the covered ends 2a of the sheath 2 inserted into the insertion holes 28 can be easily inserted into both ends 6.7 of the case body 5, and the optical fiber unit 3 can be inserted into the caps 8.8. It can be inserted into the branch pipe section 10,
Moreover, the case body 5 can be tightened by tightening the band 9.
Since both ends 6.7 of the case body 5 are completely sealed, the work of attaching the case body 5 to the cable is extremely simple, and the case body 5 has excellent drip-proof and waterproof properties.

Note that the present invention is not limited to the illustrated embodiment, and the design may be changed without departing from the gist of the present invention. For example, it is preferable that the case body 5 is made expandable instead of being divisible. In this case, the half body 5a.

One of the corresponding outer flanges 17 and 17 of 5a is arranged in a continuous manner to form a hinge portion. Therefore, if it is made expandable in this way, there is no need to attach a fixing tool to this hinge portion, so that the attachment work can be made easier.

In addition, the backing plate 25 is attached to the outer flange 17 of each half body 5a, 5a.
It is preferable that the cap 8 is made of an elastic material such as rubber or synthetic resin.
Although one branch pipe section 10 is inserted into each branch pipe section 0, it is of course free to provide two or more branch pipe sections 10, and it is also free to provide only one branch pipe section 10 in the case body 5. Furthermore, in the illustrated example, an optical fiber unit 3 is provided within the sheath 2.
Although the optical fiber cable 4 is used, it is also preferable to use an optical fiber cable 4 in which a cored optical fiber 48 is linearly contained within the sheath 2.

〔Effect of the invention〕

If the optical fiber cable branching structure of the present invention is used, the optical fiber core 48 or the optical fiber unit 3 exposed from the coated end 2a of the sheath 2 will not be affected by temperature changes in the outside air. Deterioration of the optical fiber core 48 due to temperature changes can be prevented. (In other words,
If this structure is used, the optical fiber core wire 48 will have good □ property at temperature. ) Also, since the covering member 37 is made of a mixture that can be crushed by a slight external force, it can be easily
The case body 5 can be taken out from the covering member 37 by disassembling the covering member 37. Therefore, when changing the branching part (predetermined part), etc., this work is easy, and the case body 5 can be reused.
It's very convenient. Furthermore, since the covering member 37 does not directly contact the optical fiber coated wire 48 or the optical fiber unit 3, the optical fiber coated wire 48 or the optical fiber unit 3 will not be damaged during disassembly work.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is a side view showing the case body, Fig. 3 is an enlarged sectional view of the optical fiber unit, and Fig. 4 is a simplified diagram sequentially explaining the branching method. It is. 2... Sheath, 2a... Covered end, 3... Optical fiber unit, 4... Optical fiber cable, 5...
Case main body, 10... Branch pipe portion, 37... Covering member, 48... Optical fiber core wire, F... Branch fiber. Patent applicant Mitsubishi Cable Industries, Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. Branching of an optical fiber cable having a plurality of coated optical fibers or optical fiber units inside the sheath to branch out the coated optical fibers or optical fiber units to the outside of the sheath. a part structure that covers the optical fiber coated wire or the optical fiber unit exposed from the coated end of the sheath at a predetermined part of the cable, and also covers the branched fiber of the optical fiber coated wire or the optical fiber unit. A hollow case body having a branch pipe portion guiding the case to the outside; and a covering member made of a mixture of polyurethane resin or the like that is crushed by a slight external force and sealingly covers the case body from the outside. An optical fiber cable branch structure characterized by: