JP2975104B2 - Optical fiber cable and its laying method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical fiber cable constituting an optical communication path and a method of laying the same.

(Prior art)

2. Description of the Related Art In recent years, information communication networks using optical fibers as transmission media have been created in various places. Most of them are dedicated lines between large-scale communication terminals such as a small number of large-scale business establishments, and between large-scale communication terminals and information communication bases equipped with large-scale computers. Communication between small-scale communication terminals such as homes and between small-scale communication terminals and information communication bases equipped with large-scale computers are performed using telephone lines. The reason why the telephone line is used for communication regarding each small communication terminal is as follows. That is, since telephones have a high penetration rate, telephone lines are laid in most of the houses where the small-scale communication terminals are to be installed, and are easy to use.

On the other hand, when another transmission medium is used, there are the following problems. That is, for example, when an optical fiber cable is erected, it is necessary to construct a telephone pole dedicated to the erection, and when burying an optical fiber cable underground, it is necessary to construct an underground conduit. This is because the cost of these constructions is high.

In order to reduce such construction costs, a method of installing an optical fiber cable in an existing connection route network such as a sewerage pipe network in which a connection route to each house is established can be considered. Small businesses and households that use information communication using optical fiber as a transmission medium are characterized by being concentrated in urban areas. The route of the optical fiber cable can be secured.

A sewer pipe network is a branch pipe that is a pipe that joins and flows sewage from each house in a predetermined area, and a main pipe that is a pipe that joins sewage from a plurality of branch pipes and flows to a sewage treatment plant. It is constituted by.

When laying an optical fiber cable in the sewerage pipe network configured as described above, the optical fiber cable is extended from the main pipe to each branch pipe. Optical fiber cables are drawn into individual houses by using manholes provided for a large number of branch pipes of the sewerage piping network for inspection and operation as branch points and connection points of the optical fiber cables. Of these manholes, the optical fiber cables are drawn. A method of drawing an optical fiber cable from the manhole closest to the house performing the above to the house has been considered. When laying an optical fiber cable in a sewer pipe in this way, the sewer pipe is designed so that the maximum amount of sewage occupies 80% of the capacity of the pipe. Cables must be routed.

FIG. 13 is a sectional view of a sewerage pipe showing a state where optical fiber cables are laid in a conventional sewerage pipe.

In the figure, reference numeral 103 denotes an L-type metal fitting. The metal fitting 103 is driven into the uppermost portion of the inner wall every predetermined distance in the axial direction of the sewage pipe 101, so that the optical fiber cable has a circular cross section.
Reference numeral 102 is fixed to the upper wall in the sewer pipe 101 so as to be sandwiched between the metal fitting 103 and the inner wall.

[Problems to be solved by the invention]

However, when the optical fiber cable is fixed to the upper part in the sewer pipe 101 using the L-type fitting 103 as described above, the optical fiber cable 102 has a relatively large diameter, and a part thereof is It becomes an aspect which protrudes below the area of 20% of the inner upper part. For this reason, a part of the optical fiber cable 102 is easily immersed in sewage, so that there is a problem that the life of the cable is shortened.
Is a cantilever beam and has low strength, and may be detached by high-pressure water cleaning performed when cleaning the sewer pipe 101.

The present invention has been made in view of such circumstances, and uses an optical fiber cable having a flat cable duct having a hollow portion in the center thereof, and attaches a fixing member penetrating the hollow portion to an upper portion of a sewer pipe. To provide an optical fiber cable and a method of laying the optical fiber cable, which fix the cable duct by driving the optical fiber cable into a wall to make the optical fiber cable hard to be immersed in sewage, prolong the cable life and improve the fixing strength of the optical fiber cable. With the goal.

[Means for solving the problem]

The optical fiber cable according to the present invention is an optical fiber cable having a cable duct for inserting an optical fiber therein, wherein the optical fiber cable has a hollow portion at a central portion in a width direction thereof, and the plurality of holes for inserting the optical fiber are provided. It is characterized by having one or more layers of flat cable ducts arranged side by side on both sides in the width direction of the cavity.

The method for laying an optical fiber cable according to the present invention is a method for laying an optical fiber cable, wherein the optical fiber cable is laid on an underground road. The cable duct is driven into a wall, and the cable duct is fixed to the upper wall at an appropriate length in the length direction.

[Action]

In the optical fiber cable of the present invention, since the cable duct has a flat shape, it is easy to lay even if the space for laying is narrow, and when laying, the space is not significantly narrowed, and a plurality of layers are formed. Therefore, a large number of optical fibers can be inserted.

In the method of laying an optical fiber cable according to the present invention, the fixing member is driven into the upper wall of the underground road through the hollow portion of the optical fiber cable. It will be supported, the fixing strength is high, and the cable duct has a flat shape, so the fixing height of the optical fiber cable from the upper wall of the underground road is relatively low, and it is present in the optical fiber cable and the underground road Interference with objects is reduced.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic block diagram showing the overall configuration of an optical communication path to which the optical fiber cable according to the present invention is applied.

In the figure, 12, 12,... Are branch pipes of the sewerage pipe network.
At 12…, drainage from houses 2,2… is the respective drainpipe 13,13…
The branch pipes 12 and 12
Are provided with a number of manholes 3 for inspection and work. Here, the manhole 3 is a hole for work and inspection including not only a hole through which an operator can enter, but also a small hole through which an operator cannot enter.
The branch pipes 12, 12 are respectively connected to main pipes 11, 11, ... of a sewerage pipe network extending over a long distance section.
… The sewage flowing through the main pipes 11,11 that pass directly to the sewage treatment plant 1
… To each of them. The sewage flowing into the main pipes 11, 11,... Is collected in the sewage treatment plant 1 and subjected to sewage treatment. The sewage treatment plant 1 is provided with a large-scale computer, and equipment for providing and managing optical communication information.

As described above, in the sewerage pipe network, the route from the sewage treatment plant 1 to the houses 2, 2, ... and the route between the houses 2, 2, ... are connected by the drain pipe. The optical fiber cable, which is the transmission medium of the optical information communication device, is connected to the main pipes 11, 11,.
And the branch pipes 12, 12,... In each of the houses 2,2, optical fiber cables branched in the manholes 3,3, closest to the house 2,2, have branch pipes 12,12, and drain pipes 13,13.
... and drawn through.

FIG. 2 is a schematic perspective view showing a laid state of the optical fiber cable according to the present invention. In FIG. 2, reference numeral 91 denotes house 2
The private tub 91 is connected to the end of the drain pipe 13. Also drain pipe
A public basin 92 serving as a drainage reservoir is provided in the middle of 13.
The drain of the house 2 is drained from the private measure 91 to the drain pipe 13 through the public measure 92.
It flows through the inside and flows into the branch pipe 12. An optical fiber cable is installed in the main pipe 11 from the sewage treatment plant 1, and a plurality of optical fiber cables on the trunk line 6 are provided in a main manhole (not shown) for maintenance and inspection provided in a plurality of paths in the main pipe 11. The branched optical fiber cable is installed as a branch line 7 in the branch pipe 12.

When the optical fiber cable is led into each of the houses 2, 2,..., The branch line 7 is branched in the junction box 4 attached to the lower part of the cover of the manhole 3, and the branched optical fiber cable is used as the house line 8. It is extended to the house 2 through the branch pipe 12, the drain pipe 13, the public yard 92, and the private yard 91. The optical fiber cables drawn into the houses 2, 2,... Are connected to an optical modem (not shown) that converts an optical communication signal (or an electric signal) into an electric signal (or an optical communication signal). The optical modem is connected to a terminal for optical communication, and a signal converted by the optical modem is supplied to the terminal. Further, the electric signal provided from the terminal to the optical modem is converted into an optical communication signal, and is branched via the house line 8 and supplied to the junction box 4.

When the optical fiber cable installed in this manner is used, communication between the sewage treatment plant 1 and each of the houses 2, 2,... Is possible, and optical communication between each of the houses 2, 2,. .

The optical fiber cable used for the branch line 7 is configured by inserting an optical fiber core wire into a cable duct 70 having a flat axial cross section.

FIG. 3 is a schematic axial sectional view of a cable duct 70 used for the branch line 7. In the figure, reference numeral 70 denotes a cable duct that covers the optical fiber core wire. The cable duct 70 has a cable fixing hole 70a, which is a wide cavity, formed at the center in the width direction of the cable duct 70, and also has a cable fixing hole 70a. A flat duct is formed by forming a plurality of insertion holes 70b, 70b,... Each having a circular cross section for inserting an optical fiber core wire on both sides in the width direction of the hole 70a. The cable duct 70 is made of a material having good elasticity, such as polyethylene resin and vinyl chloride resin.

Next, a method of attaching the cable duct 70 to the inside of the branch pipes 12, 12,... Will be described. Fig. 4 shows the branch pipe 1 of the cable duct 70
A schematic longitudinal sectional view of the branch pipe 12 showing an attached state in 2,12 ...
FIG. 5 is a schematic axial sectional view of the branch pipe 12.

The cable duct 70 is disposed so as to be in contact with the upper wall surface in the branch pipe 12, and is fixed to the upper wall surface by a plurality of fixing brackets 71 for fixing the cable duct 70 at a predetermined distance in the axial direction of the branch pipe 12. You. The fixing bracket 71 is formed by projecting a rod-shaped embedding portion 71b at the center of the convex surface of a base 71a bent at a curvature substantially equal to the inner peripheral surface of the branch pipe 12. The fixing bracket 71 is such that the embedded portion 71b is a cable duct 70.
Is inserted into the upper wall of the branch pipe 12 so as to pass through the cable fixing hole 70a, and the embedding portion 71b is embedded in the upper wall. In this way, the cable duct 70 is connected to the base 71a.
And the upper wall surface. In this case, the width direction of the cable duct 70 is bent along the wall surface of the branch pipe 12, and the cable duct 70 is laid in the branch pipe 12 such that the upper surface of the cable duct 70 contacts the upper wall surface.

When such a cable duct 70 is laid in the branch pipes 12, 12,... As described above, the optical fiber cables are branched and connected at the respective manholes 3 existing in the paths of the branch pipes 12, 12,. 3 must be laid so as to connect the branch and the connection box 4 attached to the lower part of the lid. When laying the cable duct 70 as described above,
The distance between the manholes 3 is generally 30 m to 50 m, but the total length of the cable duct 70 laid in each branch pipe 12 is
Since the cable length is 1000 m or more, if a method of connecting the cable ducts 70 after laying them between the manholes is used, the construction cost is high and the amount of work is increased, so the method shown in FIG. 6 is used.

FIG. 6 is a schematic longitudinal sectional view of the manholes 3, 3,... And the branch pipe 12 for explaining the method of laying the cable duct 70. When laying the cable duct 70, as shown by the broken line in the figure, the cable duct 70 is entirely inserted into the branch pipe 12 in advance, and then the cable duct 70 existing at the bottom of each manhole 3, 3,. As shown by, it is lifted upward and branched and stored in the connection box 4. If such a method of laying the cable duct 70 is used, the amount of work required for laying the cable duct 70 can be reduced.

Although the cable duct 70 as described above is for inserting the branch line 7, it is also possible to insert the house line 8 branched from the branch line 7. Seventh
The figure is an axial sectional view of a two-layer cable duct through which the branch line 7 and the house line 8 are inserted.

This two-layer cable duct 700 has a second duct 702, which is a duct for inserting the house line 8 along the first duct 701, on the lower surface of the first duct 701 having the same configuration as the cable duct 70 as described above. It is attached using materials. The second duct 702 is a flat duct made of the same material as the cable duct 70, and has a plurality of house line insertion holes 702b, 702b for inserting the optical fiber core wire of the house line 8.
Are formed in parallel in the width direction.

Next, the branch pipes 12 and 12 of such a two-layer cable duct 700 will be described.
The method of attaching to... Will be described. FIG. 8 is a schematic longitudinal sectional view of the branch pipe 12 showing a state in which the two-layer cable duct 700 is mounted in the branch pipe 12.

The two-layer cable duct 700 is installed in the branch pipe 12 in the same manner as when only the cable duct 70 is mounted as shown in FIG. Are fixed to the upper wall surface by metal fittings 71, 71. In this case, the second duct 7 of the two-layer cable duct 700
The portion where the fixing metal fitting 71 is attached in 02 is removed so that the base 71a of the fixing metal fitting 71 reaches the lower surface of the first duct 701. Fixing with the fixing bracket 71
Is inserted into the upper wall of the branch pipe 12 so as to pass through the cable fixing hole 701a of the first duct 701, and the embedding portion 71b is embedded in the upper wall. Thus, the first duct 70
The two-layer cable duct 700 is attached to the upper wall of the branch pipe 12 such that 1 is sandwiched between the base 71a and the upper wall surface.

When the house line 8 is drawn into the drain pipe 13 of the house 2 from the second duct 702 of the two-layer cable duct 700, it is performed as shown in FIG. FIG. 9 is a schematic sectional view showing a state where the house line 8 is drawn from the two-layer cable duct 700 into the drain pipe 13 of the house 2. When the house line 8 is drawn into the drain pipe 13, the second duct closest to the target drain pipe 13 is used.
A part of 702 is broken, and the house line 8 is pulled out from the break and drawn into the drain pipe 13.

The cable duct 70 thus configured is connected to the branch pipes 12,12.
… When laying the cable inside, lay the cable duct 70 without passing the optical fiber core wires through the insertion holes 70b, 70b in advance, and then, if necessary, insert the optical fiber into the insertion holes 70b, 70b. Insert the fiber core.

In this embodiment, the two-layer cable duct 700
The second duct 702 has an axial cross section as shown in FIG. 9 and employs a method of removing a part of the second duct 702 when the two-layer cable duct 700 is installed. However, the present invention is not limited to this. As shown in Fig. 10, the cable duct
A cable fixing hole 72a similar to 70 may be provided at the center in the width direction of the second duct 702. When the two-layer cable duct 700 having this structure is mounted in the branch pipe 12, the embedded 71b is used to fix the cable. It is fixed with the fixing bracket 71 so as to penetrate the holes 701a and 702a.

Further, in the present embodiment, when the cable duct 70 branches and enters the connection box 4, the flat cable duct 70 (or the two-layer cable duct 700) directly branches and enters the connection box 4. However, the present invention is not limited to this. As shown in the vertical sectional view of the manhole 3 showing the mounting state in FIG. 11, a flat-shaped cable duct 70 (or a two-layer cable duct 70) and a circular cross section are formed on the side wall at the bottom of the manhole 3. A connection box 7001 for connecting to the cable duct 7000 may be attached, and a circular cable duct 7000 may be provided between the connection box 7001 and the branch / connection box 4. Such a circular cable duct 7000 is easier to handle when bending the duct than the flat cable duct 70 (or the two-layer cable duct 700). If it is used for the duct inside 3, the branching inside the manhole 3 and the work of connecting the duct to the connection box 4 can be easily performed. When such a circular cable duct 7000 is used, a combined duct formed by connecting the cable duct 70 and the circular cable duct 7000 in the junction box 7001 at the time of manufacturing the cable duct 70 (or the two-layer cable duct 700) and the circular cable duct 7000. 70000 are connected and formed in advance. Then, as shown in FIG. 12, a vertical sectional view of the branch pipe 12 showing the method of laying the return duct 70000, the return duct is inserted into the branch pipe 12 as it is, and the circular cable duct 7000
Branching method and a method of pulling up to the connection box 4 may be used.

In this embodiment, the cable duct 70 is connected to the branch pipe 1.
When laying in 2, 12, ..., the optical fiber cores are inserted after the cable duct 70 is laid, but the invention is not limited to this, and a necessary number of optical fiber cores are inserted in the cable duct 70 in advance. May be. If the nominal wire for inserting the optical fiber core is inserted in advance into the insertion holes 70b, 70b,... Where the optical fiber core is not inserted in advance, the subsequent operation of inserting the optical fiber core is easy. Becomes

In this embodiment, the insertion hole of the cable duct 70 is provided.
70b, 70b... Allow only the optical fiber core wire to pass therethrough. However, the present invention is not limited to this. Of these through holes 70b, 70b, the outermost through holes 70b, 70b or the innermost through holes 70b, 70b
The structure may be such that the tension member is inserted through
When the tension member is inserted in this manner, the bending strength of the cable duct 70 increases.

Further, in this embodiment, the cable duct 70 is fixed in the branch pipes 12, 12,... By penetrating the fixing fitting 71 into the cable fixing hole 70a, which is a hollow portion of the cable duct 70. May be filled with a foamed resin or an adhesive.

Further, in the present embodiment, the equipment for providing and managing the information of the optical communication is provided in the sewage treatment plant 1, but the present invention is not limited to this, and the information communication base having the equipment is provided in a place other than the sewage treatment plant 1. Drainage pipe 13 provided at the information communication base
Alternatively, the trunk line 6 may be installed in the main pipe 11 via the branch pipe 12, and an optical communication network centered on the trunk line 6 may be installed. Further, in the present embodiment, the optical fiber cable is laid in the sewer network, but the present invention is not limited to this, and if it is an underground communication route network having a plurality of manholes 3 at predetermined intervals, an underground cable,
A communication route network such as a common gutter and an underground pipe may be an object for laying the optical fiber cable.

〔effect〕

The present invention is as described above, and uses an optical fiber cable having a flat cable duct with a cavity in the center thereof, so that the mounting height to the upper wall of the underground road is reduced, and this optical fiber cable is used. Since the optical fiber cable is fixed to the upper wall of the sewer pipe with a fixing member, the optical fiber cable is hardly immersed in sewage, and the present invention is excellent in that the life of the cable can be extended and the fixing strength of the optical fiber cable can be improved. It has the effect.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an overall configuration of an optical communication path to which an optical fiber cable according to the present invention is applied, FIG. 2 is a schematic perspective view showing an installation state of the optical fiber cable in the optical communication path, and FIG. 3 is a schematic axial sectional view of a cable duct used for a branch line, FIG. 4 is a schematic longitudinal sectional view of a branch pipe showing a cable duct installed in a branch pipe, and FIG. 5 is a schematic axis view of the branch pipe. FIG. 6 is a schematic longitudinal sectional view of a manhole and a branch pipe for explaining a cable duct laying method, FIG. 7 is a schematic axial sectional view of a two-layer cable duct through which a branch line and a house line are inserted, FIG. 8 is a schematic longitudinal sectional view of a branch pipe showing a state in which a two-layer cable duct is installed in a branch pipe, and FIG. 9 is a schematic cross section showing a state where a house line is drawn from a two-layer cable duct into a drain pipe of a house. Fig. 10, Fig. 10 shows other two-layer cable ducts Fig. 11 is a vertical sectional view of a manhole showing a state of attachment of a circular cable duct, Fig. 12 is a vertical sectional view of a branch pipe showing a method of laying a return duct, and Fig. 13 is a conventional sewer pipe. It is sectional drawing of the sewer pipe which shows the installation state of the optical fiber cable inside. 7 ... branch line, 12 ... branch pipe, 70 ... cable duct, 70a ... cable fixing hole, 70b ... insertion hole, 71 ... fixing bracket, 700 ... two-layer cable duct

──────────────────────────────────────────────────続 き Continuation of the front page (72) Yoshifumi Takahashi 7-36-17 Minamikoiwa, Edogawa-ku, Tokyo (72) Inventor Sadayoshi Fujihira 5-7-6 Nakano, Nakano-ku, Tokyo (72) Inventor Noboru Okazaki 3-19-19-108, Kamiishikami, Nerima-ku, Tokyo (72) Inventor Kenjiro Iishi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Akihiro Ishiseki, Shimbashi, Minato-ku, Tokyo 6-4-9 Mitsubishi Electric Engineering Co., Ltd., Tokyo Office (72) Inventor Junichi Ueda 4-3-1 Ikejiri, Itami-shi, Hyogo Mitsubishi Electric Wire & Cable Co., Ltd. Itami Works (72) Inventor: Moriyuki Fujita Tokyo 3-4-1 Marunouchi, Chiyoda-ku (Shin Kokusai Building) In the Tokyo office of Mitsubishi Cable Industries, Ltd. (56) References JP-A-1-138924 (JP, A) Japanese Unexamined Patent Publication No. 3-270613 (JP, A) Japanese Unexamined Patent Publication No. 4-121100 (JP, A) Japanese Unexamined Patent Publication No. 4-186304 (JP, A) Japanese Utility Model Application Sho 62-109117 (JP, U) Japanese Utility Model Application Sho 62 -89605 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/00 G02B 6/44 H02G 1/06

Claims (2)

(57) [Claims] 1. An optical fiber cable having a cable duct through which an optical fiber is inserted, wherein the optical fiber cable has a hollow portion at a central portion in a width direction thereof, and a plurality of holes through which the optical fiber is inserted are formed in the width of the hollow portion. An optical fiber cable having one or more layers of flat cable ducts juxtaposed on both sides in the direction. 2. A method for laying an optical fiber cable according to claim 1, wherein the member penetrating the hollow portion is driven into the upper wall of the underground road via the hollow portion. And fixing the cable duct to the upper wall at an appropriate length in the longitudinal direction thereof.