JP3437053B2 - Fiber optic cable - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing the number of optical fiber cables accommodated in one underground pipeline in order to effectively use pipeline facilities laid underground. Increased optical fiber
About the cable. 2. Description of the Related Art When the amount of communication between routes increases and the amount of communication lines becomes insufficient, it becomes necessary to add an optical fiber cable. In this case, a method of burying a new underground pipe or effectively using an existing underground pipe can be considered. The construction of new underground pipelines cannot be promptly responded to due to traffic conditions, etc., and construction of new underground facilities requires a great deal of cost. Therefore, it is important to make effective use of existing facilities. Therefore, in order to effectively use the existing equipment, a method of newly laying an optical fiber cable in a vacant space of an underground conduit in which a communication cable has already been laid has generally been adopted. FIG. 12 shows a conventional method of laying a cable after a route when the amount of communication between routes increases and the amount of communication lines becomes insufficient. As shown in the drawing, in addition to the existing cable 12, a cable duct 13 for laying a hollow cable is provided inside the underground conduit 11.
Is laid. Therefore, a traction string 15 is laid so as to penetrate through the inside, and a rear laying cable 14 to be laid later is connected to one end of the traction string 15 via a towing terminal 16. Thereafter, the laid cable 14 is pinched by a set of rollers 17 ', which are rotatable and can move the cable 14 in the longitudinal direction. Similarly, the other end of the pulling string 15 is pinched by the pulling roller 17 and the rear cable 14 is pulled into the rear cable cable duct 13 by traversing the pulling string 15 by rotating in the direction of the arrow. Was possible. FIG. 13 is a flow chart S10 showing an outline of an operation sequence relating to a conventional method of laying an optical cable.
Indicated by First, a cable duct 13 for laying is laid in an empty space of the underground conduit 11 (S11), and a traction string 15 is laid in the cable duct 13 for laying (S1).
2). Next, the towing string 15 is connected to the towing terminal 16 of the rear laying cable 14 (S13), and the towing string 15 is towed by the traction machine 17 to lay the rear laying cable 14 in the cable duct (S14). . Thereafter, the towing string 15 is removed, and a series of post-laying work is completed (S1).
5). FIG. 14 shows an example of a cross section of the underground conduit 11 at the time of “multiple installation” using a conventional optical fiber cable and a rear installation duct 13. Generally, this multi-laying is performed when the outer diameter of the container 12 is smaller than the outer diameter of the underground conduit 11 and there is a sufficient free space between the container 12 and the underground conduit 11 as shown in the figure. This is the only laying method used. Conventionally, when it is necessary to efficiently lay an optical fiber cable in response to the demand for an optical fiber communication line, one method is to use an optical fiber cable with connectors at both ends, which is provided with optical fiber tapes at both ends. However, since there is no method for accurately measuring the length of the pipeline, there is no connector on one side, and the other is cut and fused after adjusting to the length of the pipeline. The method of wearing was used. [0007] As described above, in the conventional post-laying method, there is a cable housed in the underground conduit 11 in advance, and when a new optical fiber cable 14 is to be added, the post-laying method is required. When the installation optical fiber cable 14 is towed, extra tension due to obstacles such as earth and sand and humus products mixed in the underground conduit 11 is applied to the installation optical fiber cable 14 after that, and unforeseen pulling or cutting due to excessive pulling. In some cases, caution is required because the post-laying work is difficult. Thereafter, the traction string 15 is pulled into the cable duct 13 for rear installation, and the traction string 15
And the rear-laying optical fiber cable 14 is connected, and then the pulling string 15 is pulled by the pulling machine 17 to lay the rear-laying optical fiber cable 14 in the rear-laying cable duct 13. . In addition, there is a need for a means for accurately and easily determining the length of a conduit in which an optical fiber cable with connectors at both ends is to be laid when designing a line, and a method for realizing an efficient laying operation. Accordingly, the present invention provides a cable duct in which a traction string is incorporated in advance, a cable duct for laying, an optical fiber cable, and a strength member are included when a new optical fiber cable is laid on a route where communication demand is expected to increase. Its main purpose is to save labor in operation due to drawing into the pipeline and to prevent unexpected failure accidents such as cutting accidents due to obstacles such as earth and sand in the pipeline. It is. [0010] In order to solve the above problems and achieve the object, the present invention takes the following measures. First, the optical fiber cable has a housing fiber optic cable having an outer diameter smaller than the inner diameter of the coating within the same coating, a tensile strength member for pulling the entire optical fiber cable, and an internal
The optical fiber cable pulling string for rear installation is accommodated in
Made to accommodate a plurality of after laying cable duct that, before
The inner surface of the sheath of the optical fiber cable and housed in this sheath
And the new optical fiber
The outer surface of the duct for laying the cable
The surface of the strength member has uneven shapes that are in contact with each other.
Providing a fiber optic cable that is taped or made of rubber-based material , and fastening the end of a new fiber optic cable to one end of the fiber optic cable traction string;
By pulling the other end and then pulling it into the cable duct for laying, it is possible to reduce the laying work. In addition, when the assembly of the cable duct for installation and the optical fiber cable housing after the tow of the optical fiber cable with the connector at both ends to be installed according to the present invention is housed, the length thereof is described. Keep it. At the time of post-laying, the length of the optical fiber cable with connectors on both ends is determined on the basis of the stated length, so that post-laying with a small extra length is achieved. Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings by way of examples. FIG. 1 shows an optical fiber cable 20 according to the present invention.
FIG. 2 is a flowchart showing a procedure of a post-laying operation using the cable. As shown in FIG. 1, during the coating of the optical fiber cable 20 laid in the underground conduit, in addition to the already laid optical fiber cable 21, three cable laying cable ducts 22 are provided at the center. It is provided around the penetrating strength member 23. After that, one traction cord 15 is housed in advance in each of the cable ducts 22 for installation. In the post-laying operation, one end of the pulling string 15 is connected to a new rear-laying optical fiber cable 14 via the pulling terminal 16. Accordingly, the towing cord 15 is driven by the towing machine 17 or the like, so that the optical fiber cable 14 for installation can be pulled into the cable duct 22 and installed thereafter. When a new communication demand is generated, the same post-laying operation as described above may be repeatedly performed on one of the other two empty cable ducts 22 and the optical fiber cable may be added to perform the multi-laying. it can. That is, according to the flowchart S20 in FIG. 2, first, the rear laying cable duct 22 is laid if desired (S21). By using the optical fiber cable 20 of the present invention having the above-described structural features for rear laying, the traction string 15 is connected to the traction terminal 1 of the rear laying cable 14.
6 (S22). Then, the other end of the towing cord 15 is towed by the towing machine 17, and then the installation cable 14 is drawn into the duct 22 and installed (S23). Thereafter, the towing cord 15 is removed, and a series of post-laying work is completed (S24). (Function and Effect 1) As described above, in the optical fiber cable of the present invention, the cable duct 22 for laying the rear cable and the pulling string 15 for the optical cable 14 for laying the rear fiber are previously provided in each cable duct 22 for laying the rear fiber. For this reason, the cable laying work for laying the cable duct and the work of laying the pulling string therethrough are not required, and the work process can be reduced. In addition, since the rear-laying cable duct 22 is provided in the covering with an optimal design, the outer diameter of the rear-laying optical cable 14 can be made larger than before, and as a result, the number of cores accommodated in one conduit can be increased. . [Embodiment 2] Conventionally, at the time of manufacture, a connector is attached to only one end of an optical fiber, transported to a laying site, laid in a pipeline, and thereafter, the optical fiber cable is cut according to the length of the pipeline. The current situation is to attach a connector to the other end and connect it to another cable, but this method requires a long time at the installation site and requires a long time to connect the optical fiber and the connector. Is performed on site, the communication quality of the connection unit is not always constant. Therefore, in the present invention, the optical fiber cable is provided with means for determining the length of the conduit. For example, as described above, the cable duct 22 for laying after the traction string 15 is accommodated therein and the optical fiber cable 20
If the length of the duct is measured and recorded in advance at that time, the length of the optical fiber cable with the connector at both ends to be laid later is determined before the laying operation. You can decide. Therefore,
After the towing string 15 is connected to the towing terminal 16 of the optical fiber cable 31 with the both ends connector of the length determined in the cable duct 22 for rear installation, the towing string 15 is towed by the towing machine 17 so that the length is almost equal to the length. Can be laid after the minimum necessary length. More specifically, FIG. 3 shows a structure of a cable 19 having a connector for both-end laying according to the present invention.
Specifically, for example, a “cable length” (not shown) is printed on the covering surface of the cable 19. Then, based on the data, the required length of the optical fiber cable to be newly laid later is estimated, and the optical connector 1 previously connected to both ends with optical fiber tapes 28 at the time of manufacture.
8 is attached. When a new demand arises, optical fiber cables with connectors at both ends are repeatedly laid in the other rear laying cable duct 22 in the same manner. FIG. 4 is a flowchart S30 illustrating a procedure for laying the optical fiber cable with the rear-end double-ended connector shown in FIG. 3 on the cable 20 of the present invention.
First, when the cable 20 of the present invention having the above-described structural feature for laying is laid, the length of the cable is measured and recorded at a predetermined location (S31). Based on the cable length, the length of the optical fiber cable 19 with connectors on both ends to be installed later is determined (S32). The traction string 15 provided in the cable laid beforehand is connected to the terminal of the cable for laying back (S3).
3) Pull out the towing cord 15 with the towing machine 17 and lay a new cable 19 in the duct 22 (S3).
4). Thereafter, the towing cord 15 is removed, and a series of post-laying work is completed (S35). (Effect 2) Since the length of the optical fiber cable required for the post-laying is at least the length of the existing cable or longer, if this cable length is described as a means for determining the length of the pipeline, Measurement for post-laying or
The connector mounting process according to this result can be reduced from on-site work. Therefore, according to the work procedure shown in FIG.
The working time at the cable laying site can be reduced, and the communication quality can be prevented from lowering. Further, from the obtained data on the length, the length of the optical fiber cable with connectors at both ends can be laid with a small excess length. Embodiment 3 FIG. 5 is a sectional view of an optical fiber cable according to an embodiment of the present invention.
Shows this longitudinal structure. As shown in the drawing, there is a single housing in which a bundle of optical fiber cables 21 is housed, and three rear laying cables housing traction strings 15 for an optical fiber cable (not shown) to be laid later. As shown in FIG. 6, the duct 22 is arranged in a "straight line" in the longitudinal direction around a strength member 23 for pulling the entire optical fiber cable 20, and a sheath made of, for example, polyvinyl chloride is provided around the duct 22. To constitute one optical fiber cable 20. (Effect 3) A cable duct 22 for back-laying, which is provided in advance on this optical fiber cable.
The towing string 15 eliminates the need to lay the cable duct and the towing string in the cable duct in the post-laying work, so that the work process can be reduced. Further, since the plurality of rear-laying cable ducts 22 are optimally provided, the outer diameter of the rear-laying optical cable can be increased as compared with the conventional case, and therefore, the number of cores accommodated in one conduit can be increased. [Embodiment 4] FIG. 7 is a sectional view of an optical fiber cable 21 as the above-mentioned container.
As shown in the figure, a tensile member 26 made of, for example, a metal steel wire or a fiber reinforced plastic rod is provided at the center. For example, it is a long round bar-shaped one made of a plastic material such as polyethylene, and has a “helical” or S-shaped and Z-shaped composite twist, that is, an “SZ twist” groove 27 on its peripheral surface. A plurality of optical fibers (not shown) are accommodated along the groove 27. Further, a predetermined holding tape called an optical fiber tape 28 is wound around the inner periphery of the coating layer of the container to form a holding roll layer for the optical fiber. A sheath 29 made of polyvinyl chloride is provided on the periphery. (Effect 4) By using a metal steel wire or a fiber reinforced plastic rod for the tensile member 26, an optical fiber cable which is strong in longitudinal tension and highly flexible can be obtained. Further, for example, by providing a groove of “SZ twist”, a plurality of optical fibers are easily accommodated along this groove,
Further, the optical fiber is stably accommodated by the holding by the optical fiber tape 28. [Embodiment 5] FIG. 8 shows a so-called "SZ type" housing structure of a cable according to an embodiment of the present invention. That is, the optical fiber cable 2 of the present invention
At 0, the cable duct 22 for laying the optical fiber cable 20 after accommodating the accommodating body 21 accommodating the optical fiber and the traction string (not shown) of the three optical fiber cables (not shown) to be laid later are housed. As shown in the figure, the cable ducts 22 and the inner surface of the housing are twisted into the "SZ shape" at appropriate intervals on the periphery of the tensile strength member 23 for pulling the cable. A sheath 25 made of vinyl is provided. (Function / Effect 5) As described above, the accommodation body 21 accommodating the optical fiber and the duct 22 accommodating the pull cord 15 for pulling the optical fiber cable are arranged at the center in an appropriate number of combinations. "S twist" and "Z twist" are alternately and repeatedly twisted in the longitudinal direction at appropriate intervals with respect to the tensile strength member 23, and an optical fiber cable provided with a sheath on the periphery thereof is used for post-laying as compared with the related art. The outer diameter of the optical cable can be increased, so that the number of cores accommodated in one conduit can be increased and stable accommodation is possible. [Embodiment 6] An optical fiber cable 20 according to an embodiment of the present invention shown in FIG. 9 is configured as follows. That is, the container 21 in which the optical fiber is stored
And a cable duct 22 for laying the fiber optic cable to be laid after three laying laces are helically wound around the strength member 23 for pulling the optical fiber cable 20 at an appropriate interval period. And a sheath made of, for example, polyvinyl chloride is provided around the cable duct 22 and the housing 21. (Function and Effect 6) As described above, the housing 21 accommodating the optical fibers and the ducts 22 accommodating the traction cords 15 are formed in a suitable number of combinations around the strength member 23 at a predetermined pitch. As described above, the outer diameter of the post-laying optical cable can be increased as compared with the conventional case, and thus the number of cores accommodated in one pipeline can be increased by twisting in a "helical shape" in the longitudinal direction and providing a sheath around the periphery. And can be stably stored. Embodiment 7 FIG. 10 shows a cross-sectional structure of a cable according to an embodiment of the present invention. This structural feature is that the surface of the container 21 illustrated in FIG. 5, the outer surface of the cable duct 22, the surface of the central tensile strength member 23, and the inner surface of the coating of the cable 20 are made of a high friction material, which will be described later. The point is that the high friction material tape 30 is wound. For example, a tensile member 23 made of a metal steel wire or a fiber reinforced plastic rod is provided at the center, and a cable duct 22 for laying a cable after laying a plastic made of, for example, polyethylene is provided around the strength member 23. Further, for pulling, for example, a rod-shaped strength member 23 in which the circumference of a strength member 23 made of a metal steel wire or a fiber-reinforced plastic rod is covered with plastic such as polyethylene is twisted at an appropriate interval around the center. A sheath made of polyvinyl chloride. Further, on the peripheral surface of each of the container 21, the cable laying cable 22 for the rear laying, and the strength member 23 which constitute the optical fiber cable 20,
For example, a high friction tape 30 made of a rubber material is wound. (Function and Effect 7) By coating the surface with such a material exhibiting a high frictional force, it becomes difficult for adjacent members to slide with each other, and the position is stabilized in the coating. In addition, the high friction tape 30 wrapped around the peripheral surfaces of the rods of the housing 21, the cable laying cable 22, and the tensile strength member 23 can suppress the shrinkage due to the temperature change of each rod. (Other Modified Embodiments) In order to maintain the high frictional force as described above, a material suitable for each may be adopted, or a periodic projection (convex) may be formed on the surface as shown in FIG. Part) may be provided. That is, rectangles as shown in FIG. 11A may be regularly arranged, and may be wound by a high friction tape 30 having a large number of projections having a sectional shape as shown in FIG. 11B. As a result, a high frictional force is generated that makes it difficult for the adjacent concave and convex portions to engage with each other and to slide, and the accommodated cables and cable ducts are positionally stabilized. The cable laying cable 22 is made of a plastic material such as polyethylene. Further, the traction string 15 may be made of, for example, a metal steel wire or a high-strength polymer fiber. Further, the strength member 23 is, for example, a metal steel wire or a fiber reinforced plastic rod covered with a plastic material such as polyethylene on the periphery. In addition, the material of these parts is not necessarily limited to the above materials, and other materials may be appropriately used. In addition,
Various modifications may be made without departing from the spirit of the present invention. As described above, the optical fiber of the present invention is
When the cable is used, the work efficiency of the rear laying can be improved by using the cable duct for the rear laying in the cable and the pulling string of the existing rear laying cable. In addition, since the cable duct for rear installation can be efficiently provided in advance, the outer diameter of the optical cable for rear installation or the outer diameter of the container is increased, and as a result, the number of optical fibers accommodated in the rear installation cable is significantly increased. It is possible to easily increase the number of accommodated cores per pipeline.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a method for laying multiple optical fiber cables according to the present invention. FIG. 2 is a flowchart showing a procedure of a method for laying multiple optical fiber cables according to the present invention. FIG. 3 is a schematic view showing an optical fiber cable with connectors at both ends according to the present invention. FIG. 4 is a flowchart showing a procedure of a method for laying multiple optical fiber cables with connectors at both ends in FIG. 3; FIG. 5 is a transverse sectional view showing a sectional structure of the optical fiber cable according to the present invention. FIG. 6 is a perspective view partially showing a longitudinal structure of the optical fiber cable of the present invention. FIG. 7 is a cross-sectional view showing a cross-sectional structure of an optical cable housed in the optical fiber cable of the present invention. FIG. 8 is a perspective view partially showing a longitudinal structure forming an “SZ type” of the optical fiber cable of the present invention. FIG. 9 is a perspective view partially illustrating a “spiral” longitudinal structure of the optical fiber cable of the present invention. FIG. 10 is a cross-sectional view showing the cross-sectional structure of the optical fiber cable of the present invention in which a high friction material is applied to the surface of the housing, the outer surface of the cable duct, the surface of the strength member, and the inner surface of the cable coating. 11A and 11B show a surface shape of a high frictional force tape to which a high frictional force is applied, wherein FIG. 11A is a plan view of the high frictional force tape, and FIG. 11B is a view of the high frictional force tape along a line AA ′. Longitudinal section. FIG. 12 is a schematic view showing a conventional method of laying multiple optical fiber cables. FIG. 13 is a flowchart showing the procedure of a conventional method for laying multiple optical fiber cables. FIG. 14 is a cross-sectional view showing a conventional cable cross-section structure for laying multiple optical fiber cables. [Description of Signs] 14: Optical fiber cable for rear installation, 15: Tow cord, 16: Towing terminal, 17: Towing machine, 18: Optical connector, 19: Cable with both ends connector, 20: Optical fiber cable (coating), DESCRIPTION OF SYMBOLS 21 ... accommodation optical fiber cable, 22 ... rear cable laying duct, 23 ... strength member of optical fiber cable, 25 ... strength member of accommodation fiber optic cable, 27 ... groove of holding down layer, 28 ... optical fiber tape, 29 ... Coating (sheath) of the accommodated optical fiber cable, 30: high friction material tape, 31: protrusion, 32: high friction force tape material.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-220390 (JP, A) JP-A-7-302516 (JP, A) JP-A-2-95115 (JP, A) 88308 (JP, U) Japanese Utility Model Hei 6-64216 (JP, U) Japanese Utility Model Utility Model 5-38716 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/44 G02B 6 / 46

Claims (1)

(57) [Claim 1] A housed optical fiber cable having an outer diameter smaller than the inner diameter of the coating within the same coating, a tensile strength member for pulling the entire optical fiber cable, and a rear inside thereof. Light for installation
Made to accommodate a plurality of after laying cable ducts formed by accommodating the fiber cable pull cord, the covering the inner surface of the optical fiber cable, yield in the coating
And the new optical fiber
The outer surface of the duct for installing the fiber cable
The surface of the strength member has irregular shapes that are in contact with each other.
An optical fiber cable characterized in that a tape made of a rubber material is used .