JPH1062630A - Cable junction box structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily increase the number of branches after setting once by providing a first housing part for housing a fusion connecting optical fiber and a second housing part of a plurality of stages for housing a passing optical fiber. SOLUTION: An excessive length housing case 4 has a first housing part for housing a fusion connecting optical fiber 6 and a second housing part of a plurality of stages for housing a passing optical fiber 8. For example, the fusion connecting optical fiber 6 is housed in the first housing part of the excessive length housing case 4, and passing optical fibers 8 are divided into two groups and independently housed in the second housing part of two stages. An inlet passage 28 for passing a prescribed margin of the passing optical fiber 8 is formed between one outside surface 26 of the excessive length housing case 4 provided within a junction box body 3 and one inside surface 27 within the junction box body 3 opposed there to. Thus, since it is quickly found that which passing optical fiber 8 must be cut and fusion-connected when the passing optical fiber 8 is to be newly branched, the working property is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cable junction box structure for branching and connecting a cable having a plurality of optical fibers.

[0002]

2. Description of the Related Art Conventionally, as a cable connection box structure for branch connection of an optical fiber cable, as shown in FIG. 10 and FIG.
The extra-length storage case g having a one-stage lower storage portion c for storing the optical fiber e and a one-stage upper storage portion f for storing the fusion spliced optical fiber e fusion-spliced at the fusion portion d. It is known that the main body is housed in a junction box main body together with a substrate portion i to which ends n and n of the main cable a and ends of the branch cable k are fixed.

[0003]

However, in the conventional cable connection box structure as described above, all the uncut passing optical fibers b are stored in the lower storage portion c of the extra storage case g. A large number of passing optical fibers b could not be stored in groups. Therefore, when it is desired to increase the number of branches later, it takes time to find the passing optical fiber b to be branched, and the workability is poor.

[0004] Further, as shown in FIG.
When the passing optical fiber b is exposed at an intermediate portion of the optical fiber b, the optical fiber b is spirally wound with each other. For this reason, as shown in FIG.
If it is attempted to store in the two storage sections q and r, since the distance A between the ends n and n of the trunk cable a and the entrance to the storage sections q and r is narrow, m and m are wrapped around the optical fiber b. This causes problems such as a decrease in light transmission efficiency and a break in the optical fiber b.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a cable junction box structure that can easily increase the number of branches after being installed.

Another object of the present invention is to provide a cable junction box structure that can prevent the transmission efficiency of a passing optical fiber from lowering and prevent the optical fiber from being damaged.

[0007]

In order to achieve the above-mentioned object, an optical fiber cable connection box according to the present invention comprises a first storage section for storing a fusion spliced optical fiber and a first storage section for storing a passing optical fiber. An extra-length storage case having a plurality of second storage sections is provided.

In addition, a predetermined allowance for the passing optical fiber is provided between one outer surface of the extra length storage case provided in the connection box main body and one inner surface of the connection box main body facing the one outer surface. An introduction passage through which the air flows is formed.

The extra length storage case provided in the connection box main body has a first storage portion for storing the fusion spliced optical fiber and a multistage second storage portion for storing the passing optical fiber. It is composed of a long storage section and an introduction passage through which a predetermined margin of the passing optical fiber passes.

When the length of the predetermined margin is L ₁ and the length of the extra storage case is L ₂ ,
It is desirable that 0 mm ≦ L ₁ ≦ L ₂ .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the illustrated embodiments.

FIG. 1 shows an embodiment of a cable connection box structure according to the present invention. This cable connection box structure is provided at a middle portion of a trunk cable 1 having a plurality of optical fibers.
A branch box 2 having a plurality of optical fibers therein for branch connection; a connection box main body 3; a storage board 11 having a rectangular shape in a plan view housed in the connection box main body 3;
An extra-length storage case 4 housed in the connection box body 3 and fixed to the storage board 11.

The connection box body 3 is shown in FIGS. 1, 2, 3 and 4.
As shown in the figure, the upper half 3a and the lower half 3b are formed. The upper half portion 3a and the lower half portion 3b have a main body wall portion 14 having a recess 13 therein for accommodating the storage board 11, and an outer flange portion 12 for overlapping and screwing together. . Further, grooves 16 for inserting the trunk cable 1 and the branch cable 2 are provided in the outer collar portion 12. At the lower end of the lower half 3b, there are formed mounting projections 17 projecting outward and laterally.

As shown in FIG. 1 and FIG.
An extra-length storage case 4 is attached to the center of the storage board 11, and a pair of ends 1a, 1a formed for branching the trunk cable 1 and an end 2a of the branch cable 2 are formed at both ends in the longitudinal direction of the storage board 11. Fix it.

The extra-length storage case 4 has a horizontally long shelf plate member 5 in the form of an upwardly open channel which is stacked up and down at predetermined intervals and a lid-like shape above the uppermost shelf plate member 5. And a lid plate 18 attached to the In particular,
Three shelves 5 are stacked, and a space between the uppermost shelves 5 and a lid plate 18 thereon is used as a first storage section 7 for housing the fusion spliced optical fiber 6, and Optical fibers 8, 8 passing between the shelf member 5 and the second shelf member 5 from the top and between the second shelf member 5 from the top and the third shelf member 5 from the top As a second storage section 9 for storing the data.

That is, the extra length storage case 4 has a first storage portion 7 for storing the fusion spliced optical fiber 6 and a plurality of (two in the illustrated example) second stages for storing the passing optical fibers 8. 2
And a storage unit 9. In addition, on the upper surface of each shelf board member 5,
The cushion material 10 for preventing the optical fiber from being damaged is provided. Openings for passing the fusion spliced optical fiber 6 and the passing optical fibers 8, 8 are provided at both longitudinal ends of the first storage portion 7 and the second storage portion 9 of the extra-length storage case 4.

Here, the fusion spliced optical fiber 6 is defined as an optical fiber in which the optical fiber 19 of the trunk cable 1 is cut and one end thereof is fusion spliced to the optical fiber 19 of the branch cable 2. The passing optical fiber 8 is defined as an uncut optical fiber 19 of the trunk cable 1.

A trunk cable 1 and a branch cable 2
As shown in FIG. 5, an optical fiber 19, a spacer 21 provided with a plurality of concave grooves 20 on which the optical fiber 19 is fitted, and a sheath 22 covering the spacer 21 are provided.
And a tension member inserted through the axial center of the spacer 21
23. The concave grooves 20 are spirally formed on the outer peripheral surface of the spacer 21.

The optical fiber 19 is of a so-called tape type, and comprises a plurality of optical fiber cores 24 arranged in parallel.
And a coating layer 25 for coating the optical fiber cores 24.

Thus, (returning to FIGS. 1 and 4) one outer side surface 26 of the extra length storage case 4 provided in the connection box main body 3.
And one inner surface of the connection box body 3 facing the one outer surface 26
27, an introduction passage 28 for passing a predetermined margin of the passing optical fibers 8 is formed. That is, a gap between one outer surface 26 of the extra-length storage case 4 and one inner surface 27 of the connection box main body 3 facing the one outer surface 26 is defined as an introduction passage 28.

Further, when the length of the predetermined margin of the passing optical fibers 8 is L ₁ and the length of the extra length storage case 4 is L ₂ , 180 mm ≦ L ₁ ≦ L ₂ . . This multiple pass optical fiber 8 If it is 180 mm> L ₁ is,
Entangled with very small pitch to each other in the introduction passage 28 is for reduced transmission efficiency of light, also, L _1> L ₂
In this case, the length of the connection box body 3 is increased.

Also, particularly preferably, 188 mm ≦ L ₁ ≦ L
_{Assume 2} . This reduces the strain caused by bending the optical fiber by 0.2%.
When the effective radius of curvature is set to 30 mm or less, the length L ₁ of the predetermined allowance is 30 mm × 2 × π ≒ 188 mm.

Here, the branch end 1 of the trunk cable 1
The method for forming the optical fibers a and 1a and the method for connecting the optical fibers will be described. As shown in FIG. 6, the optical fiber 19 is exposed by removing the sheath 22 and the spacer 21 at the site where the trunk cable 1 is to be branched. Optical fiber 19 to be branched
Are cut, and the other optical fibers 19. Thereafter, one end of the cut optical fiber 19 is fusion-spliced to the optical fiber 19 of the branch cable 2 to obtain a fusion spliced optical fiber 6. W is a fusion splicing point.

Although FIGS. 1, 4 and 6 show only one fusion spliced optical fiber 6 and two passing optical fibers 8 in order to facilitate understanding of the present invention, actually, In the first storage section 7 and the second storage section 9, several to several tens of fusion spliced optical fibers 6 and passing optical fibers 8 are stored, respectively.

As shown in FIG. 4, the fusion spliced optical fiber 6 is stored in the first storage section 7 of the extra length storage case 4 and the passing optical fiber is stored in the second storage section 9 in two stages. 8 to 2
Divided into two groups and stored separately.

Thus, when it is desired to newly branch the passing optical fiber 8 in the future, any of the passing optical fibers 8
Since it is possible to quickly determine whether or not to cut and fusion splice, the workability is improved.

As described above, when the length of the predetermined margin is L ₁ and the length of the extra length storage case 4 is L ₂ , 180 mm ≦ L ₁ ≦ L ₂ . The passing optical fibers 8 can be easily divided into a plurality of groups (two groups in the illustrated example), and no large distortion is applied to the passing optical fibers 8 outside the extra length storage case 4.

That is, since the length L ₁ of the predetermined allowance of the passing optical fibers 8 is sufficiently large, even if the passing optical fibers 8 are separated from each other in order to be housed in the separate second housing sections 9, the passing optical fibers 8 pass through. The winding pitch of the optical fiber 8 becomes sufficiently large. Therefore, the passing optical fiber 8 bends with a large radius of curvature, so that it is possible to prevent a decrease in light transmission efficiency and to prevent the passing optical fiber 8 from breaking.

Next, FIGS. 7 and 8 show a main part of another embodiment.
Extra storage section 30 having a first storage section 7 for storing the optical fiber and a plurality of second storage sections 9 for storing the passing optical fiber 8.
And an introduction passage 31 through which a predetermined allowance of the passing optical fiber 8 passes.
And is composed of Other configurations are the same as those in FIGS.

With the above construction, the passing optical fiber 8 and the fusion spliced optical fiber 6 can be protected since the passing optical fiber 8 and the fusion splicing optical fiber 6 do not go out of the introduction passage 31. For example, when the extra length storage case 4 and the storage board 11 are stored in the connection box body 3 (not shown), the passing optical fiber 8 and the fusion splicing optical fiber 6 are interposed between the upper half 3a and the lower half 3b. There is no risk of being pinched.

The trunk cable 1 and the branch cable 2
The optical fiber accommodated in the concave groove 20 of the spacer 21
The tape 19 may be of a type other than the tape type. For example, the tape 19 may directly house the optical fibers 24. Further, as the trunk cable 1 and the branch cable 2, for example, as shown in FIG. 9, a tension member 32 at an axis portion, tubes 33 arranged on the outer periphery of the tension member 32, and tubes 33 ... Sheath 34 covering the bundle of tubes and tube 33
, And optical fibers 19 inserted therein.

Further, the second storage portion 9 of the extra length storage case 4 is not limited to the two stages shown in FIGS. 4 and 8, and may preferably have three or more stages. And spacer 21
And the number of steps of the second storage section 9 is the same,
It is particularly preferable to store the passing optical fibers 8 in the second storage section 9 separately for each of the grooves 20.

[0033]

The present invention has the following remarkable effects by the above-mentioned structure.

According to the cable connection box structure of the first aspect, the passing optical fibers 8 can be stored in a plurality of stages in the second storage portion 9 of the excess storage case 4. Therefore, when it is desired to newly branch the passing optical fiber 8 in the future, the passing optical fiber 8 to be branched can be quickly searched, and workability is improved.

According to the optical fiber cable connection box structure of the second aspect, the second storage portion 9 of the extra length storage case 4
The passing optical fibers 8 can be stored in a plurality of stages. Further, outside the extra length storage case 4, the passing optical fibers 8 are curved with a large radius of curvature, so that a decrease in light transmission efficiency can be prevented and the passing optical fibers 8 can be prevented from being broken.

According to the optical fiber cable junction box structure of the third aspect, the same effects as those of the first and second aspects can be obtained, and the passing optical fiber 8 and the fusion splicing optical fiber 6 can be moved from the introduction passage 31. Since it does not go outside, the passing optical fiber 8 and the fusion spliced optical fiber 6 can be protected.

According to the optical fiber cable connection box structure of the fourth aspect, the same effects as those of the second or third aspect can be obtained, and the connection box body 3 can be made compact. Further, it is possible to more effectively prevent the light transmission efficiency from being lowered and the passing optical fibers 8 from being damaged.

[Brief description of the drawings]

FIG. 1 is a main part plan view showing an embodiment of the present invention.

FIG. 2 is a plan view of a main part of a connection box main body.

FIG. 3 is a plan view of a main part of the connection box main body.

FIG. 4 is a sectional view of a main part.

FIG. 5 is a sectional view of a cable.

FIG. 6 is an explanatory diagram of a method of forming an end portion of a trunk cable.

FIG. 7 is a plan view of a main part of another embodiment.

FIG. 8 is a sectional view of a main part.

FIG. 9 is a sectional view of another cable.

FIG. 10 is a plan view of a main part of a conventional example.

FIG. 11 is a sectional view of a main part of a conventional example.

FIG. 12 is an explanatory diagram of a comparative example.

FIG. 13 is an explanatory diagram of a comparative example.

[Explanation of symbols]

3 Connection Box Main Body 4 Extra Length Storage Case 6 Fusion Spliced Optical Fiber 7 First Storage Part 8 Passing Optical Fiber 9 Second Storage Part 26 Outer Side 27 One Inner Side 28 Introductory Path 30 Extra Length Enclosure 31 Introductory Path L ₁ the length L ₂ length dimension

Claims (4)

[Claims] An extra length storage case having a first storage portion for storing a fusion spliced optical fiber and a plurality of second storage portions for storing a passing optical fiber is provided. Cable junction box structure. 2. A predetermined allowance for a passing optical fiber between one outer surface of an extra-length storage case provided in the connection box main body and one inner surface of the connection box main body opposed to the one outer surface. A cable junction box structure, characterized in that an introduction passage through which the air flows is formed. 3. An extra-length storage case provided in the connection box main body has a first storage portion for storing the fusion spliced optical fiber and a multistage second storage portion for storing the passing optical fiber. A cable connection box structure comprising: a long storage section; and an introduction passage through which a predetermined allowance for a passing optical fiber passes. Wherein the length of the predetermined margin and L _1, the length of the slack storage case is taken as L _2, 180 mm ≦
4. The cable connection box structure according to claim ₂ , wherein L ₁ ≤L ₂ .