JPH07306322A - Optical fiber introducing structure in connecting box of optical fiber composite overhead earth wire - Google Patents

Abstract

PURPOSE:To make it possible to introduce an optical fiber into a connecting box without cutting this fiber and to impart high waterproofness to an optical fiber introducing part. CONSTITUTION:A side wall 50 of a connecting box body is provided with a two-stage tapered recess 51 expanded on the outer side. The bottom of this recess 51 is provided with a socket part 52 having a semicircular recess shape. The inner end side of a two-step tapered fixture 53 formed into a shape perfectly adaptable to this socket part 52 having the two-stage tapered shape is provided with a semicircular recess-shaped pressing part 54 facing the socket part 52. This fixture 53 is constructed by molding an elastic material to the outer side of an arbor. A sealing tape layer 67 formed by winding a sealing tape is held on the outer side of an optical fiber unit 1 exposed from the inner end of the part clamped by the mouthpiece of the overhead earth-wire by means of the socket part 52 and the semicircular recess-shaped pressing part 54 of the fixture 53. The fixture 53 is press-fitted and fixed into the recess 51 of the body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber introducing structure which can introduce an optical fiber into an optical fiber connection of an optical fiber composite overhead ground wire without cutting the optical fiber.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional optical fiber composite overhead ground wire A.
FIG. In this figure, reference numeral 1 denotes an optical fiber unit, which is a spacer 3 made of aluminum or the like having a plurality of spiral grooves 2 on the outer circumference, an optical fiber 4 housed in each spiral groove 2 and a pipe 5 made of aluminum or the like covered on the outer side of the spacer 3. It consists of

A plurality of aluminum-coated steel wires 6 are twisted around the outer periphery of the unit 1. The overhead ground wire A as described above was connected in the connection box B for each unit length as shown in FIG.

In FIG. 9, C is an introduction part provided on the side wall of the junction box B, and there are several places, and the overhead ground wire A is provided at this introduction part C.
Was attached, and only the exposed optical fiber 4 in the introduction portion C was connected by the optical fiber connector 7 with a sufficient extra length.

FIG. 10 shows a conventional example of the introduction section C. In the introduction portion C, the aluminum-coated steel wire 6 at the end portion of the optical fiber composite overhead ground wire A is removed to expose the optical fiber unit 1, and a sealing tape layer 8 is provided on a part of the outer periphery of the exposed unit 1. An O-ring 9 and a ring-shaped press fitting 10 are fitted on both ends of the tape layer 8.

A base 11 is screwed into a screw hole formed in the side wall of the connection box B and fixed, the end of the optical fiber unit 1 is inserted into the base 11, and the inner base 1
2 is screwed into the outer end of the base 11.

[0007] Then, a waterproof external structure C is constructed by covering the portion extending from the base 11 to the optical fiber overhead ground wire A on which the steel wire 6 is wound with the external fastening metal fitting 13 and tightening with a bolt. .

[0008]

In the above-mentioned conventional example, the optical fiber 4 drawn out from the optical fiber unit 1 and connected in the connection box B needs to have a sufficient extra length, and the length is about 2 It reaches ~ 3m.

The optical fiber unit 1 is attached to the O-ring 9 and the ring-shaped retainer 10 in anticipation of the long introduction length as described above.
It is extremely difficult to insert, position, and fix from the tip, and there is a problem that the structure is complicated and many parts are required.

There is also a device as disclosed in Japanese Utility Model Laid-Open No. 62-197103, in which a base body is divided into two parts, and the base body is fixed to a connection box by using a flange portion. However, there is a problem in that the end of the optical fiber unit of the overhead ground wire held by the base has to be passed through the hole of the connection box.

In general, the optical fiber composite overhead ground wire A has a unit length that reaches the number of steel towers, and the optical fiber 4 was connected in the connection box B for each unit length. When it is necessary to collect information such as wind speed at a steel tower in the middle of the overhead ground wire A, cut all the optical fibers 4 on the spot, and then introduce them into the connection box B and connect them. There must be.

In this case, all the optical fibers 4 are required regardless of the number of optical fibers 4 required for collecting information.
Therefore, there is a problem that connection loss due to unnecessary connection increases and wasteful construction cost also increases.

An object of the present invention is to provide an optical fiber introducing structure in a connection box which can be introduced into the connection box without cutting the optical fiber, and also provides an optical fiber introducing structure having a high waterproof property. .

[0014]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention exposes a part of an optical fiber unit of an optical fiber composite overhead ground wire for a predetermined length, and the optical fiber composite overhead ground wire is exposed. The ground wire gripping part for holding the part where the optical fiber of the wire is not exposed and the part for holding the exposed optical fiber unit while keeping the waterproof part are formed continuously. In a connection box using a base of a structure, a two-step tapered recess with an enlarged outer side is provided at a required part of the side wall of the connection box body, and a semicircular recessed receiving part is provided at the bottom of this recess. The semi-circular recessed receiving portion is formed on the inner end side of the two-step tapered fixing tool that is detachably attached to the two-step tapered recessed portion as a shape that perfectly fits the two-stepped tapered recessed portion. A semi-circular recess that forms a circular hole facing the The two-step taper-shaped fixture has a structure in which an elastic body is molded on the outside of the cored bar, and the outside of the optical fiber unit exposed from the inner end of the portion of the overhead ground wire gripped by the base A sealing tape layer formed by winding a sealing tape on the above-mentioned two-step taper-shaped recessed portion of the semi-circular recessed receiving portion and the same as the above-mentioned recessed portion of the two-step taper fixing tool semi-circular recessed pressing portion. A structure was adopted in which the fixture was pressed and fixed in the recessed part of the main body while sandwiching it.
In addition, an endless groove is provided on the upper edge of the side wall of the junction box and on the upper edge of the fixture fitted in the recess of the side wall, and the watertightness between the side wall and the lid is maintained by the endless packing fitted in this groove. Also adopted.

[0015]

1 to 6, D is a junction box used in the embodiment of the present invention, 50 is a side wall of the junction box,
E is an introduction part of the optical fiber.

A recessed portion 51 having a two-step taper shape with an enlarged outer side is formed in a portion of the side wall 50 which constitutes the introduction portion E, and a semicircular recessed receiving portion is formed at the bottom thereof. Part 52
To form. Further, a two-step taper-shaped fixture 53 that fits the recessed portion 51 is provided, and the inner end side of the fixture 53 is
A pressing portion 54 having a semicircular recess is formed to face the receiving portion 52.

The fixture 53 is formed by molding an elastic body 56 such as rubber around the outer circumference of a cored bar 55. Reference numeral 57 in FIGS. 2 and 3 denotes a ferrule, which includes an overhead ground wire grip portion 61 integrally fixed to a flange 60, and an overhead ground wire grip portion 62 facing the overhead ground wire grip portion 62.

The flange 60 has a rectangular shape as shown in FIG. 2, and is fixed to the outside of the side wall 50 by bolts 63 inserted through the insertion holes at the four corners. Further, both gripping portions 61 and 62 are plate-shaped as shown in FIG. 2, and the overhead ground wire A is provided in the center portion facing each other.
The semi-circular grooves 64, 65 into which the
As shown in FIG. 2, a notch 66 reaching the center of the semicircular groove 64 is provided from the side on which the grip 61 is not provided, and the optical fiber unit 1 is inserted from here.

Now, as shown in FIG. 8, the aluminum-coated steel wire 6 in a necessary portion of the overhead ground wire A is cut out for a required length to expose the optical fiber unit 1, and the exposed optical fiber unit 1 is exposed. The outer pipe 5 is cut off for about 2 to 3 m to expose the spacer 3 and each optical fiber 4, the necessary optical fiber 4 is cut, and the exposed spacer 3 is cut and removed, but the others are as they are. And

The unit 1 exposed as described above is inserted into the notch 66 of the flange 60, and the overhead ground wire A where the unit 1 is not exposed is sandwiched and fixed by the grooves 64 and 65, and the opposite grips are provided. The bolts 68 and nuts inserted into the bolt insertion holes of the projecting portions on both sides of the portions 61 and 62 are integrally tightened.

Then, as shown in FIG. 3, a sealing tape is wound around a portion of the unit 1 projecting from the flange 60 and in contact with the flange 60 to provide a sealing tape layer 67. The radius of the layer 67 is the semicircle. The radius of the shape receiving portion 52 and the pressing portion 54 is set to be slightly larger than the radius of the pressing portion 54 so that the receiving portion 52 and the pressing portion 54 adhere to the sealing tape layer 67 during assembly.

The flange 60 of the base 57 assembled as described above is applied to the side wall 50 and fixed with the bolt 63, and the sealing tape layer 67 is attached to the receiving portion 52 of the side wall 50 and the side wall 50.
Clamp it with the retainer 54 of the fixture 53 fitted in the recess 51 of the
A plurality of bolts 69 inserted into the insertion holes of the fixture 53 are screwed into the screw holes provided in the step portion of the side wall 50 to be fixed.

Grooves 70 and 71 are formed in the upper edge of the side wall 50 and the fixing tool 53, and an endless O-ring 73 fitted in the grooves 70 and 71 is fixed to the side wall 50 by bolts. It is brought into close contact with the lid 72.

The above-mentioned introduction portion E is provided at two places on the side wall 50 of the connection box D as shown in FIG. 1, and the uncut optical fiber 4 is housed in the connection box D with several turns and cut.
Is connected to the information collecting unit 41 by the optical fiber connector 7.

The introduction portion F of the optical cable 42 to the information collecting unit 41 may have a conventional structure as shown in FIG.

[0026]

As described above, according to the present invention, since the optical fiber is housed in the connection box without being cut, and only the necessary optical fiber is cut, there is no connection loss, and the optical fiber to be inserted into the connection box is not lost. There is an effect that it can be easily introduced.

Further, according to the present invention, a two-step tapered recess having an enlarged outer side is provided at a required portion of the side wall of the junction box body, and a semicircular receiving portion is provided at the bottom of the recess. As a shape that perfectly fits the stepped taper recess, the inner edge of the two-step taper fixture that is detachably attached to the two-step taper recess has a circular shape facing the semi-circular receiving part. Since the semi-circular pressing portion that forms a hole is provided and the above-mentioned two-step taper-shaped fixture has a structure in which an elastic body is molded on the outside of the core metal, this fixture is used as a two-step taper recessed portion of the side wall. The elastic body molded into the fixture is elastically deformed by being tightened with a bolt or the like and closely adheres to the inner surface of the recessed portion to ensure watertightness of this portion.

Also, a sealing tape layer formed by winding a sealing tape on the outside of the optical fiber unit exposed from the inner end of the overhead ground wire held by the mouthpiece is a semi-circular receiving portion of the two-step tapered concave portion. And the same as above, it is sandwiched by the semi-circular pressing part of the two-step taper fixing tool fitted in the recessed part, and the fixing part is press-fitted and fixed in the recessed part of the main body. The watertightness is also perfect, and together with the watertightness retaining structure by the O-ring between the side wall of the junction box and the lid, an optical fiber introducing structure having a high degree of waterproofness can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a junction box embodying the present invention.

FIG. 2 is an enlarged front view of the embodiment of the present invention.

[Fig. 3] Partial vertical sectional side view of the above.

[Fig. 4] Similarly, a rear view of the same with a partially cutaway view.

FIG. 5 is a partially cutaway perspective view of a side wall.

FIG. 6 is a perspective view of a fixture.

FIG. 7 is an enlarged cross-sectional view of an optical fiber composite overhead ground wire.

FIG. 8 is a partially cutaway side view of an optical fiber overhead ground wire with a part of the optical fiber exposed.

FIG. 9 is a plan view showing an example of a conventional junction box.

FIG. 10 is an enlarged vertical side view showing an example of a conventional optical fiber introducing section.

[Explanation of symbols]

 A Optical fiber overhead ground wire D Connection box 1 Optical fiber unit 4 Optical fiber 50 Side wall 51 Recessed part 52 Receiving part 53 Fixing part 54 Holding part 55 Core metal 56 Elastic body 66 Notch part 67 Sealing tape layer 71 Groove 72 Lid 73 O-ring

Claims (2)

[Claims] 1. A two-part split for exposing a part of an optical fiber unit of an optical fiber composite overhead ground wire over a predetermined length, and gripping a portion of the optical fiber composite overhead ground wire where the optical fiber is not exposed. In the connection box that uses a base with a split structure in which the overhead ground wire gripping part and the exposed optical fiber unit are held while maintaining waterproofness, the split box base is formed continuously. In the required part,
In addition to providing a two-step tapered recess with an enlarged outside,
A semi-circular recessed receiving portion is provided at the bottom of this recessed portion, and a two-step taper-shaped fixing that is detachably attached to the two-stepped tapered recessed portion has a shape that perfectly fits the two-stepped tapered recessed portion. A semi-circular recessed pressing portion that forms a circular hole is provided on the inner end side of the tool so as to face the semi-circular recessed receiving portion, and the two-step tapered fixing tool is an elastic body on the outside of the cored bar. And a sealing tape layer formed by winding a sealing tape on the outside of the optical fiber unit exposed from the inner end of the portion of the overhead ground wire gripped by the mouthpiece, and the half of the two-step tapered recess An optical fiber characterized by being sandwiched between a circular recessed receiving portion and a semi-circular recessed retaining portion of a two-step tapered fixing tool fitted in the same recessed portion, and the fixing tool being press-fitted and fixed in the recessed portion of the main body. Optical fiber introduction structure in junction box of composite overhead ground wire. 2. An endless groove is provided on an upper edge of a side wall of the junction box and an upper edge of a fixture fitted in a concave portion of the side wall, and an endless packing fitted in the groove makes watertightness between the side wall and the lid. The optical fiber introducing structure in a connection box for an optical fiber composite overhead ground wire according to claim 1, wherein the structure is a holding structure.