JP2009229786A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which is cut with a common tool such as a nipper, in which a coated optical fiber is not buried in an coating of the cable, and a damage due to the sticking of the ovipositor of a cicada is prevented. <P>SOLUTION: The optical fiber cable is composed of a spacer 19 which has a U-shaped cross section, houses one or more coated optical fibers 15a and is coated by an coating 17 by an extrusion molding method, wherein a notch 18 for breaking up is provided at the part of the coating 17 at which the end of an open part 19a of the spacer 19 is positioned. Further, the spacer 19 may be formed of a tensile strength material and the open part 19a of the spacer 19 may be blocked by a tape-shaped member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical fiber cable used for an intermediate branch of an optical fiber in which tension members are arranged on both sides of a plurality of optical fiber cores and are covered with a jacket.

  With the rapid spread of the Internet, etc., in addition to increasing the speed of information communication and increasing the amount of information, the construction of an optical network for two-way communication and large-capacity communication has recently progressed. FTTH (Fiber To The Home), which provides high-speed communication services, has become widespread. For this reason, an optical fiber is branched from an intermediate portion of an optical fiber cable containing a plurality of optical fibers (referred to as an intermediate branch of an optical fiber) due to the introduction of an optical fiber to a subscriber's home or the expansion of a private network. The demand for wiring work distributed to multiple homes and multiple terminals is increasing. In addition, the construction of these branch wirings is usually performed in a live line state in which signal transmission is not interrupted.

  As shown in FIG. 3A, the optical fiber is dropped to the subscriber's home H by installing a closure 2 on the nearest optical fiber cable 1 laid on a utility pole P in the city. This is performed by branching about one to two predetermined optical fiber cores. A single optical fiber cable 3 is connected to the branched optical fiber using the closure 2 and pulled down to the subscriber's home H. In addition, these optical fiber drawing works are usually performed in a live line state in which signal transmission is not interrupted.

  As the optical fiber cable 1 used for the intermediate branching of the above optical fiber, for example, as shown in FIG. 3 (B), a self-supporting type in which the main body 4 and the support wire 5 are connected by a narrow neck. Things are known. The main body 4 has a structure in which tension members 7 are arranged in parallel on both sides of a plurality of optical fiber cores 6 and covered with a cable jacket 8 to enhance the tensile strength of the cable. On both sides of the cable jacket 8, V-shaped notches 9 are provided for cutting the cable jacket 8 and taking out the optical fiber core 6 (or the optical fiber ribbon) (for example, , See Patent Document 1). Note that, at the branching portion, the support wire portion 5 is separated by cutting with a hand or a dedicated tool.

When the optical fiber core wire 6 is taken out from the middle portion of the optical fiber cable 1, after separating the support wire portion 5, a slit is made with a tool such as a commercially available nipper in order to start the notch 9 of the main body portion 4. Then, there is a risk of damaging the optical fiber core wire 6 inside. For this reason, as shown in FIG.3 (C), performing using the exclusive tool 10 called a detacher is recommended. The dedicated tool 10, for example, divides the cable jacket 8 into upper and lower jacket half portions 8 a and 8 b at the notch 9 of the main body 4 and takes out the optical fiber core 6 inside. .
JP 2005-345622 A

  By using a dedicated tool 10 such as a detacher, it is possible to cut the cable without damaging the optical fiber core wire 6 in the cable. The cable is cut about 20 cm to 50 cm, and when the cable jacket 8 is bent by cutting the outer jacket halves 8a and 8b as shown in FIG. 3C, the inner optical fiber core 6 is compressed. In response, it jumps out and the compressive stress is eliminated. However, as shown in FIG. 4, when the cable jacket 8 is cut, the optical fiber core wire 6 may remain in the cut jacket halves 8a and 8b.

FIG. 4A shows a state in which the optical fiber core wire 6 is an optical fiber tape core wire (hereinafter referred to as a tape core wire) 6a and remains buried in either one of the outer jacket halves 8a and 8b. FIG. 4B shows a state in which the optical fiber core wire 6 is a single-core optical fiber core wire 6b and remains buried in both the outer jacket halves 8a and 8b.
If the cable jacket 8 is cut off with a dedicated tool and remains in the cable jacket 8 in this manner, the optical fiber core wire is excessively bent, resulting in an increase in optical loss and a temporary transmission quality abnormality. May occur. For live optical fibers in signal transmission state, even if instantaneous loss fluctuations affect the transmission signal and increase the error rate of the signal, the loss as described above in the branch operation in the live line state Occurrence becomes a problem.

In addition, special tools are expensive because they are special tools, and the shape of the optical fiber cable differs depending on the manufacturer. Therefore, an optical fiber cable that can be torn by using a general tool is required. ing.
Further, in the conventional optical fiber cable 1 shown in FIG. 3 (B), in recent years, there have been many accidents in which a spear pierces the laying tube from the notch 9 and damages the optical fiber core wire 6. For this reason, there is a proposal that a protective wall is provided between the optical fiber core 6 and the notch 9, but there is a problem that it becomes difficult to take out the optical fiber core.

  The present invention has been made in view of the above-described circumstances, and can be cut using a general tool such as a nipper, the optical fiber core wire is not buried in the cable jacket, and the spawning tube of the cocoon An object of the present invention is to provide an optical fiber cable capable of preventing damage due to piercing.

An optical fiber cable according to the present invention is formed by covering a U-shaped spacer containing one or more optical fiber core wires with an outer sheath by extrusion molding, and the outer sheath where the tip of the opening of the spacer is located. In this part, a notch for tearing is provided.
The spacer may be formed of a tensile material, and the spacer opening may be closed with a tape-like member.

  According to the optical fiber cable of the present invention, it is possible to make a notch for cutting without damaging the optical fiber core wire by using a general tool such as a nipper at the notch portion. Moreover, the optical fiber core wire in the cable can be easily taken out without being buried in the jacket, and is also protected from damage caused by the laying of the spider spawning tube.

  An embodiment of the present invention will be described with reference to FIG. In the figure, 11 and 11 'are optical fiber cables, 12 is a main body part, 13 is a support wire part, 13a is a steel wire, 14 is a neck part, 15a is an optical fiber core wire (tape core wire), 16 is a tension member, 17 Is a jacket, 18 is a notch, 19 is a spacer, and 19a is an opening.

  The optical fiber cable 11 according to the present invention is formed, for example, in a structure in which a main body portion 12 and a support wire portion 13 are connected by a narrow neck portion 14 as shown in FIG. The main body 4 includes a spacer 19 having a U-shaped cross section accommodating a plurality of optical fiber core wires (hereinafter referred to as tape core wires) 15a, and tension members 16 on both sides so as to sandwich the spacer 19. It is arranged in parallel with the direction and is covered with a jacket 17 by extrusion molding.

  On both side surfaces of the outer cover 17 on the side where the tension member 16 is not disposed, notches 18 are provided for cutting the outer cover 17 and taking out the tape core wire 15a in the cable. The notch 18 is provided at a portion where the tip of the opening 19a of the U-shaped spacer 19 is located. When the outer cover 17 is cut off at the notch 18, the opening 19a of the spacer 19 is opened. Then, the internal tape core wire 15a is taken out. By providing the notch 18 at a portion located at the tip of the opening 19a, it is possible to cut the jacket 17 without damaging the internal tape core wire 15a even if a commercially available tool such as a nipper is used.

  Further, if the notch 18 is provided on the side opposite to the side having the support line portion 13, the tape core wire 15 a can be taken out without separating the support line portion 13, and workability is good. In this case, the opening 19 a of the spacer 19 is arranged so as to face the side opposite to the side having the support line portion 13. However, as shown in FIG. 1B, the opening 19 a of the notch 18 and the spacer 19 can be the support line portion 13. In this case, since the workability is not good for cutting the notch 18 with a commercially available tool such as a nipper, the support wire portion 13 is separated in advance.

  The U-shaped spacer 19 can be formed by extrusion molding with a resin material such as polyester, nylon, or fiber reinforced plastic (FRP). In the spacer 19, one or more tape cores 15a are accommodated in a loose state as optical fiber cores. For this reason, the tape core 15a and the spacer 19 are intermittently made of a soft resin (for example, silicon resin) so that the tape core 15a is not shifted after the cable is laid and moved to the terminal side in the sloped area or strong wind region. It may be fixed.

  In addition, by using a relatively hard plastic material as described above for the spacer 19, it has a function as a protective wall that protects the optical fiber core wire from the laying of the spawning tube (mainly Komazemi) of moths and crows. Can do. The tension member 16 can be omitted by using a tensile material for the spacer 19, as will be described later. When the tension member 16 is used, a steel wire or FRP having an outer diameter of about 0.4 mm to 0.7 mm is used as in the conventional case. The jacket 17 is made of polyethylene, flame retardant polyolefin, polyvinyl chloride, or the like, and is formed by extrusion, for example, so that the long side of the main body 12 has a rectangular shape of 5.5 mm and the short side of 3.5 mm.

The support wire portion 13 can use a steel wire having an outer diameter of about 1.2 mm to 2.6 mm as the wire 13a, and the outer diameter after coating is about 4.0 mm. The support wire portion 13 is separated from the main body portion 12 by cutting off the neck portion 14 as necessary, and is fixed to a building such as a utility pole using a fastening metal fitting or the like. The overall height of the optical fiber cable 11 including the support line portion 13 is about 10 mm, and the lateral width is about 4 mm.
In addition, when a suspended wire body such as a spiral hanger is installed in the laying path of the optical fiber cable, or when it is pulled into the basement or building as it is from the aerial laying, the supporting wire portion 13 is removed and laid. Can do.

  FIG. 1C shows an optical fiber cable 11 ′ in which the above-described support line portion 13 is removed or no support line portion 13 is provided from the beginning. The optical fiber cable 11 ′ can be formed in the same shape and structure as the main body 12 of FIG. 1B, can be supported by the above-described spiral hanger, etc. It can be laid in a fence or wired as an indoor optical cable in a building or the like. When the internal tape core wire 15a is pulled out due to the intermediate branching, the notch 18 is cut with a nipper or the like and cut as in the case of FIGS. 1 (A) and 1 (B).

  FIG. 1D shows an optical fiber cable 11 ′ in which the tension member 16 is omitted from the optical fiber cable of FIG. The optical fiber cable 11 ′ shown in FIG. 1D is a case where a U-shaped spacer 19 is formed using a steel material or a tensile material such as FRP, and the spacer 19 functions as a tension member. The tension member 16 can be omitted. Note that this cable is used in the same manner as in FIG.

  FIG. 2 is a diagram illustrating another embodiment. In the figure, 15b denotes a single-core optical fiber, 20 denotes a tape-like member, and the other reference numerals are the same as those used in FIG. 2 (A) and 2 (C) show a configuration in which a plurality of single-core optical fibers 15b are accommodated, and FIGS. 2 (B) and 2 (D) show the U-shaped spacer 19. FIG. 3 is a view showing a form in which an opening 19a is closed with a tape-like member 20.

  FIG. 2A shows a configuration in which the optical fiber cable of FIG. 1A is replaced with a plurality of single optical fiber cores 15b, and other configurations are the same as those of FIG. It is. FIG. 2C shows a form in which the tape core of the optical fiber cable of FIG. 1C is replaced with a plurality of single-core optical fibers 15b. As the single optical fiber core wire 15b, one having a coating outer diameter of 0.25 mm, 0.5 mm, or 0.9 mm can be used.

  Usually, one or two optical fibers are usually drawn down to the subscriber's home, and therefore, a single optical fiber core wire 15b is accommodated as in the example of FIGS. 2 (A) and 2 (C). In such a case, there is no need to divide the optical fiber cores in a lump state like a tape core wire (usually 4 cores or more), and the branching operation becomes easy.

  FIG. 2B shows a configuration in which the opening 19a of the U-shaped spacer 19 of the optical fiber cable of FIG. 1A is closed with a tape-like member 20, and the other configuration is shown in FIG. It is the same. FIG. 2D shows a configuration in which the opening 19a of the U-shaped spacer 19 of the optical fiber cable of FIG. 1C is closed with a tape-like member 20, and other configurations are shown in FIG. Same as C). The tape-like member 20 can be a resin tape such as polyester, nylon, FRP, etc., similar to the spacer 19.

  The tape-like member 20 is in contact with the opening 19a of the spacer 19 to block the opening 19a, and prevents the molded resin material of the outer cover 17 from entering the spacer 19, and is bonded to the opening 19a. Not in. Therefore, when the notch 18 is cut with a nipper or the like, the tape-like member 20 is detached from the opening 19 a of the spacer 19, and the tape core wire 15 a can be easily taken out from the spacer 19.

  When the tape-shaped member 20 is not used, the jacket resin slightly enters the spacer 19 from the opening 19a during the extrusion of the jacket, but the amount of the resin entering the spacer 19 is small, and the notch 18 is cut off. Can be easily removed by hand. Therefore, although it does not cause much trouble in the operation of taking out the optical fiber core wire, the tape core wire 15a (or the single-core optical fiber core wire can be more easily formed by closing the opening 19a with the tape-like member 20. 15b) can be removed.

It is a figure explaining embodiment of the optical fiber cable by this invention. It is a figure explaining other embodiment of the optical fiber cable by this invention. It is a figure explaining a prior art. It is a figure explaining the conventional problem.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 11 '... Optical fiber cable, 12 ... Main-body part, 13 ... Support wire part, 13a ... Support wire part wire, 14 ... Neck part, 15a ... Optical fiber core wire (tape core wire), 15b ... Optical fiber core wire ( Single optical fiber core), 16 ... tension member, 17 ... jacket, 18 ... notch, 19 ... spacer, 19a ... opening, 20 ... tape-like member.

Claims (3)

  A spacer having a U-shaped cross-section containing one or more optical fiber cores is covered with an outer casing formed by extrusion molding, and a slit is formed in the outer casing where the tip of the opening of the spacer is located. An optical fiber cable provided with a notch.   The optical fiber cable according to claim 1, wherein the spacer is formed of a tensile strength material.   The optical fiber cable according to claim 1 or 2, wherein the opening of the spacer is closed with a tape-like member.

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