JP3079045B2 - Cable junction box structure - Google Patents

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 object, a cable connection box according to the present invention has an optical fiber.
In the middle part of the trunk cable to be
In a cable junction box structure for branch connection
The extra length storage case provided in the connection box main body accommodates the fusion spliced optical fiber and has the
A first accommodating portion provided with an opening through which the fusion spliced optical fiber is passed , and both ends in the longitudinal direction for accommodating the passing optical fiber;
A plurality of second storage portions each having an opening through which the passing optical fiber is passed , and the extra length storage case.
One outer surface of the base and the connection box book facing the one outer surface
A predetermined amount of the passing optical fiber
Forming an introduction passage through Yudai and branching the trunk cable
Light passing through one end of the pair of ends formed for
Pass the fiber allowance through the introduction passage and on the other end side
Through the opening of the second storage section located at
Increase the allowance for the passing optical fiber at the other end of the cable.
The second passage passing through the introduction passage and located at one end side.
Pass the passing optical fiber through the opening of the storage section to the second storage section.
It is configured to be stored in

Further , a trunk cable having an optical fiber therein
A branch cable with an optical fiber inside
In the cable junction box structure for branch connection, the extra length storage case provided in the junction box body holds the fusion spliced optical fiber.
The first storage section for storing and the multiple
It has a surplus storage section having several stages of second storage sections and an introduction passage through which a predetermined allowance for the passing optical fiber is provided.
Further, the above-mentioned first storage portion is provided with
An opening for passing the fusion spliced optical fiber is provided and
The passing optical fiber is provided at both ends in the longitudinal direction of the second storage section.
Openings for the trunk cable are provided.
Light passing through one end of the pair of ends formed for
Pass the fiber allowance through the introduction passage and on the other end side
Through the opening of the second storage section located at
Increase the allowance for the passing optical fiber at the other end of the cable.
The second passage passing through the introduction passage and located at one end side.
Pass the passing optical fiber through the opening of the storage section to the second storage section.
It is configured to be stored in

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 .

[0010]

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 junction box structure according to the present invention. This cable junction box structure is provided with a plurality of optical fibers 19. Branch cable 2 having optical fibers 19 inside
Is connected for branch connection, and the connection box body 3
A rectangular storage board 11 stored in the connection box body 3 and a storage board 11 stored in the connection box body 3
And an extra-length storage case 4 fixed to the

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.

Further, as shown in FIGS.
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. In addition, as shown in FIG.
In the embodiment, a branch cable is provided on the right end 1a side of the trunk cable 1.
The case where the end 2a of the bull 2 is fixed is illustrated.

The extra-length storage case 4 has a horizontally long shelf plate member 5 in the form of an open channel which is stacked up and down at predetermined intervals, and a cover-like member 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 stages (two stages in the illustrated example) 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 35a... 35b... Through which the fusion spliced optical fiber 6 and the passing optical fibers 8, 8 pass 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 . But
Each is arranged. To explain in more detail,
Delivery case 4 is located between trunk cable 1 and branch cable 2.
Provided in the longitudinal direction of the cable, provided at both ends
The openings 35a ..., 35b ... are branches of the trunk cable 1.
Located on the side of the pair of end portions 1a, 1a (described above) formed for
Will be done.

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.

Also, the trunk cable 1 and the 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 FIG. 1 and FIG. 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.

It is particularly preferable that 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
a, To explain 1a forming method and an optical fiber connection method, as shown in FIG. 6, At a site to be branched trunk cable 1, a pair of end by removing the sheath 22 and the spacer 21
The portions 1a, 1a are formed to expose the optical fiber 19, the optical fiber 19 to be branched is 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 FIGS. 1 and 4, the fusion spliced optical fiber 6 is inserted into the first storage portion 7 of the extra length storage case 4.
And the passing optical fibers 8 are separately stored in two groups of two storage sections 9 in two groups. This and
One of a pair of ends 1a, 1a of the trunk cable 1
The margin of the passing optical fiber 8 on the end 1a side (left side in FIG. 1).
Through the introduction passage 28 and the other end 1a (right side in FIG. 1).
Through the opening 35a of the second storage section 9 located at
Of the passing optical fiber 8 on the other end 1a side of the wire cable 1
Allowance is passed through the introduction passage 28 and located on one end 1a side
Passing through the opening 35b of the second storage portion 9
The bag 8 is stored in the second storage section 9. Also, the fusion splicing optical fiber
Also at the end 6, a margin is provided on the end 2 a side of the branch cable 2.
And the margin on the end 1a side of the trunk cable 1 are
Through the opening of the first storage section 7 located on the side opposite to
Will be delivered.

Thus, in the case where the passing optical fiber 8 is to be newly branched in the future, any of the passing optical fibers 8 may be used.
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 portions 9, the passing optical fibers 8 are not separated. The winding pitch of the optical fiber 8 becomes sufficiently large. In addition, one end 1 of the trunk cable 1
The margin on the a side is set to the second storage part on the opposite side to the end 1a.
9 through the opening 35a and the other end of the trunk cable 1
The margin on the side of the end 1a is set to the second side on the side opposite to the end 1a.
By passing through the opening 35b of the storage unit 9 and storing,
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.

FIGS. 7 and 8 show a main part of another embodiment, in which the extra length storage case 4 has a fusion spliced optical fiber 6.
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, the has. Furthermore, the longitudinal direction of the extra length storage case 4
The fusion spliced optical fiber 6 and the passing optical fiber
Openings 35a,..., 35b.
Other configurations are the same as those in FIGS.

With the above configuration, the passing optical fiber 8 and the fusion spliced optical fiber 6 do not go out of the introduction passage 31, so that the passing optical fiber 8 and the fusion spliced optical fiber 6 can be protected. 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 it is preferable to 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.

[0032]

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.

Further, the extra length second housing portion 9 of the housing case 4, a passage optical fiber 8 ... can be stored separately in a plurality of stages. Also, 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 breaking.

[0035] According to the optical fiber cable junction box structure according to claim 2, wherein, with the same effects as those of claim 1 Symbol placement, pass optical fiber 8 and the fusion splicing optical fibers 6
Does not go out of the introduction passage 31, so that the passing optical fiber 8 and the fusion spliced optical fiber 6 can be protected.

According to the optical fiber cable junction box structure according to claim 3, wherein, with the same effects as those of claim 1 or 2, can be made compact junction box body 3. 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.

[Description of Signs] 1 Main cable 1a End 2 Branch cable 3 Connection box main body 4 Extra length storage case 6 Fusion spliced optical fiber 7 First storage section 8 Passing optical fiber 9 Second storage section 26 Outer side surface 27 Inside side 28 introduction passage 30 slack storage section 31 introducing passage 35a opening 35b opening L ₁ length L ₂ length

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-43639 (JP, A) JP-A-8-194120 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/00 G02B 6/24 H02G 15/08

Claims (3)

(57) [Claims] 1. A trunk cable having an optical fiber therein.
In the middle, connect a branch cable with an optical fiber
In the connection box structure that follows,
The extra length storage case accommodates the fusion spliced optical fiber and passes the fusion spliced optical fiber through both ends in the longitudinal direction.
A first storage section in which an opening is provided, and a passing optical fiber which is stored at both ends in the longitudinal direction while storing the passing optical fiber.
A plurality of second storage sections, each having an opening through which the opening is provided ,
An outer surface of the extra-length storage case;
Between the inner surface of the connection box body facing the outer surface,
Form an introduction path through the specified allowance for the passing optical fiber.
And a pair of ends formed for branching the trunk cable
The allowance for the passing optical fiber at one end of the
The second storage portion which is passed through the entrance passage and located on the other end side
At the other end of the trunk cable.
Through the introduction path of the passing optical fiber
Through the opening of the second storage section located on the side of
To store the passing optical fiber in the second storage section.
Cable junction box structure characterized in that the. 2. A trunk cable having an optical fiber therein.
In the middle, connect a branch cable with an optical fiber
In the cable connection box structure to be continued, the extra length storage case provided in the connection box body stores the fusion spliced optical fiber.
A plurality of stages for storing the first storage section and the passing optical fiber
A slack storage section and a second housing portion of the introduction passage through a prescribed margin of the passing optical fiber, which has a, is
Further, the above-mentioned fusion splicing is performed on both ends in the longitudinal direction of the first storage section.
An opening through which a continuous optical fiber is passed;
Pass the passing optical fiber through both ends in the longitudinal direction of the storage section
Openings are provided respectively and are formed for branching of the trunk cable.
Passing optical fiber at one end of a pair of formed ends
Through the introduction passage and at the other end
Through the opening of the second storage section
The allowance for the passing optical fiber at the other end of the
The second storage portion passing through the passage and located at one end side
Pass the optical fiber through the opening in the second storage section
A cable junction box structure characterized by having been constituted so that it might be. Wherein the length of the predetermined margin and L _1, surplus
The length of the long storage case is taken as L _2, 180 mm ≦
3. The cable connection box structure according to claim _{1, wherein} L ₁ ≤L ₂ .