JP4888409B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to an optical fiber cable that is used as a drop optical cable or an indoor optical cable, in which tension members are arranged on both sides of an optical fiber core and are collectively 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) service that provides high-speed communication services has been started. The optical fiber is branched from the middle part of the optical fiber cable containing a plurality of optical fibers by pulling the optical fiber into the subscriber's home or expanding to the local network (this is said to be an intermediate branch of the optical fiber). ) Demand for wiring work distributed to 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.

  For example, as shown in FIG. 3A, an optical fiber cable used for an intermediate branch of an optical fiber generally has tension members 2 arranged in parallel on both sides of an optical fiber core 1 and is connected by a cable jacket 3. A structure in which the tensile strength of the cable is increased by covering all at once is used. One end of the cable jacket 3 has a support wire portion 4 that can be removed by tearing with a hand or a dedicated tool. On both sides of the cable jacket 3, the cable jacket 3 is torn and an internal optical fiber is provided. The V-shaped notch 5 for taking out the core wire 1 is provided (for example, refer patent document 1).

  When the optical fiber core wire 1 is taken out from the middle portion of the optical fiber cable, first, the support wire portion 4 is removed, then a notch 5 is opened to start tearing, and then the notch 5 is manually broken along the notch 5. Tearing to enlarge. FIG. 3 (B) is a view showing a state in which the notch 5 is torn and then the tear is torn to the left and right. When the cable is torn open to the left and right, the distance between the ends of the tear is compressed, so that the inner optical fiber core wire 1 jumps out and curves.

  There is also a method of using a special tool 6 to cut the optical fiber core in the cable without severing or scratching the cable jacket (see, for example, Patent Document 2). The tool 6 is usually called a detacher, and has, for example, a shape having a lower gripping portion and an upper gripping portion and having a hook-like protrusion at the tip of the gripping portion.

In addition, the drop optical cable is usually provided with the V-shaped notch described above, but there are cases in which a spear pierces the laying tube from this notch portion and damages the internal optical fiber. This is presumed to be the recognition of the drop optical cable as an object that can easily be laid by a cocoon. As a measure against this wrinkle, for example, a configuration in which a hard protective member (tape) is disposed on both sides of the optical fiber core wire on the side where the tension member is not disposed to protect it (for example, (See Patent Document 3).
JP 2005-345622 A JP 2000-121839 A JP 2006-11166 A

  When performing an intermediate branch of an optical fiber cable, when the optical fiber in the cable is taken out by tearing the middle part of the cable, the optical fiber core is subjected to compressive stress in the axial direction until the optical fiber core 1 jumps out. In some cases, a large loss fluctuation may occur instantaneously by meandering in the cable jacket. In addition, the optical fiber core wire that protrudes to the outside and is bent is freed from compressive stress but increases transmission loss due to bending. During signal transmission, if a large loss fluctuation occurs even instantaneously, the transmission signal will be greatly affected and the error rate of the signal will be increased. It becomes.

  For this reason, when tearing the optical fiber cable, a special tool is used so that the optical fiber is not stressed or bent, and the optical fiber core in the cable can be removed without being cut or damaged. The torn work that was done. However, the dedicated tools for this purpose are expensive because they are special tools, and the shape of the optical fiber cable varies depending on the manufacturer. There is a problem of cost.

Further, it is conceivable that the distance between the bottom of the V-shaped notch and the optical fiber core wire is reduced to facilitate the tearing of the cable. However, in this case, as also disclosed in Patent Document 3, there is a problem that the notch part is easily damaged by the laying of the spawning tube, and hard protection members are arranged on both sides of the optical fiber core wire. Protects the optical fiber from the spider spawning tube.
Also, if the notch is above the optical fiber core, a tool such as a nipper cannot be used, and even if the notch is shifted to the left or right to avoid the optical fiber, the optical fiber protection member will be on both sides. In some cases, it is difficult to penetrate with a blade, and tools like nippers cannot be used.

  The present invention has been made in view of the above-mentioned circumstances, and can cut and tear a cable jacket with a general tool such as a nipper and easily take out an optical fiber core wire in the cable. An object of the present invention is to provide an optical fiber cable capable of preventing damage to the optical fiber core wire caused by the wrinkles.

An optical fiber cable according to the present invention is an optical fiber cable in which tension members are arranged in parallel at both ends of an optical fiber core array and are covered with a cable jacket, and both sides of the cable jacket are not provided with tension members. A tear notch is provided on the surface between the optical fiber array and the tension members on both sides. A pair of release tapes are arranged so as to be in contact with the optical fiber core line and completely cover and sandwich both sides of the arrangement surface, and one of the pair of release tapes includes the other release tape and the optical fiber core. It has a projecting region that projects from both sides of the line row in the width direction, and the notch cutting axis is located in this projecting region.

In the above optical fiber cable, the notch has a notch depth on one side so that the gap between the notch tips facing each other and the peeling tape in the overhang region is close on both sides of the tape. deeply formed from the side, it may be so that the difference is small cuts force the tape both sides. Moreover, you may form a peeling tape with a resin material harder than a cable jacket.

According to the present invention, the cutting that divides the cable jacket into four in the longitudinal direction is performed by inserting the cutting blades positioned by the notches into the overhanging regions where the peeling tapes do not overlap each other so as to contact both sides of the peeling tape. Can be put. Even if the cable jacket is not largely torn from the cut portion, the optical fiber core wire separated from the cable jacket can be easily taken out. Further, this work can be easily performed with a simple tool such as a nipper without using a dedicated tool.
In addition, the release tape can effectively protect the optical fiber core wire from being damaged by the laying of the spider spawning tube.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining a first embodiment, FIG. 1 (A) is a diagram showing an example of an optical fiber cable according to the present invention, and FIG. 1 (B) is a diagram showing an optical fiber cable having no support line portion. FIG. 1 (C) is a view showing a state in which an optical fiber cable is cut, and FIG. 1 (D) is a view showing a state in which an optical fiber core wire is taken out. In the figure, 10 and 10a are optical fiber cables, 11 is an optical fiber core line, 12 is a tension member, 13 is a cable jacket, 14 is a support wire part, 14a is a neck part, 15 is a notch, 16a and 16b are peeling tapes , 20a, 20b denote cutting edges of the tool.

An optical fiber cable 10 according to the present invention, for example, as shown in FIG. 1 (A), tension members 12 are arranged in parallel on both ends of an optical fiber core line 11 composed of one or more optical fiber cores, A structure in which the tensile strength with respect to the optical fiber core line 11 is increased by being integrally covered with the cable jacket 13. The optical fiber core line 11 is positioned on both side surfaces of the cable jacket 13 on the side where the tension member 12 is not disposed so as to be positioned between the tension member 12 and the optical fiber core line 11 on both ends. A V-shaped notch 15 for cable tearing is provided with a gap M greater than the width D of the cable.
The optical fiber core line 11 in the present invention means a state in which one or more optical fiber cores are arranged in one line or two or more lines, and one or more optical fiber tape cores are laminated. It shall be.

  A pair of release tapes 16 a and 16 b that are not adhesive or are easily peeled from the cable jacket 13 on both sides of the optical fiber core line 11 are provided on both sides of the optical fiber core line 11. Arranged. One release tape 16a of the pair of release tapes is wider than the other release tape 16b. The pair of release tapes 16a and 16b are arranged so as to come into contact with the arrangement surface of the optical fiber core line 11 and completely cover both sides thereof, and together with the optical fiber core line 11 and the tension member 12, the outside of the cable. It is covered by the cover 13 at once.

  For example, a tape having the same width as the width D of the optical fiber core line 11 is used as the release tape 16b of the pair of release tapes. The release tape 16a wider than the width of the release tape 16b covers one arrangement surface of the optical fiber core line 11, and both sides protrude in the width direction from both ends of the release tape 16b and the optical fiber core line 11. Thus, it has an overhanging region S that does not overlap the peeling tape 16b and the optical fiber core line 11. The overhang region S is positioned between the tension members 12 on both sides intersecting the cutting axis X of the notch 15 and the optical fiber core line 11.

  As the peeling tape 16, a tape made of a material that has a thickness of about 0.2 mm and has poor adhesion to the cable jacket 13 and can be easily peeled off is used. As this tape, for example, by using a material having a high melting point that does not melt due to the temperature at the time of forming the cable jacket, it is possible to prevent welding between the cable jacket 13 and the peeling tape 16. As specific examples of the tape material, synthetic resin materials such as polyethylene terephthalate, polyethylene naphthalate, polyamide resin, and polyester elastomer can be used. Moreover, by making these resin materials harder than the cable jacket 13, it becomes possible to protect the optical fiber core wire from the piercing of the spawning tube of the spider.

  The optical fiber core line 11 in the present invention is a glass fiber having a standard outer diameter of 125 μm, for example, an optical fiber core wire having a coating outer diameter of about 250 μm or about 500 μm, or a reinforcing coating on the outside thereof. Formed of things. In addition, FIG. 1A shows an example in which a plurality of single-core optical fibers are arranged in two rows, but a plurality of optical fibers are formed by tape core wires integrated in a parallel row. Alternatively, a form in which a plurality of tape cores are used in an overlapping manner may be used. Also, the number of arrays can be three or four, depending on the number of optical fiber cores.

  For the tension member 12, a wire having a resistance to tension and compression, for example, a steel wire having an outer diameter of 0.4 mm to 0.7 mm, glass fiber reinforced plastic (FRP), aramid fiber reinforced plastic (K-FRP), or the like is used. It is configured to withstand long-term use against the generation of stress due to the expansion and contraction of the optical fiber in a high to low use temperature environment. Note that a steel wire having an outer diameter of about 1.2 mm to 2.6 mm can be used for the wire of the support wire portion 14.

  The cable jacket 13 has, for example, a rectangular cross section (or may be an ellipse), integrates the optical fiber core wire array 11 and the tension member 12, and protects the optical fiber from external force. As the material of the cable jacket 13, polyethylene, flame retardant polyolefin, polyvinyl chloride, or the like can be used.

  In the optical fiber cable 10 described above, when a plurality of optical fiber cores are used, the adjacent optical fiber cores may be disposed so as to contact each other and also contact the peeling tape 16. desirable. In the case where a plurality of tape cores are used, it is desirable that the tape cores and the peeling tape 16 are closely overlapped with each other. Thus, when the cable jacket 13 is formed, the resin material of the cable jacket 13 does not enter the gap between the optical fiber cores and the gap between the optical fiber cores and the peeling tape 16, and the optical fiber cores and the strips are peeled off. It is possible to coat the tape 16 so that the periphery of the tape 16 is not surrounded by the resin material of the cable jacket 13.

  As shown in FIG. 1 (A), the optical fiber cable 10 is provided with a removable support wire portion 14 connected by a narrow neck portion 14a at one end of the cable jacket 13, and is a self-supporting aerial type. The shape is suitable for use as a cable. The support wire portion 14 can be removed and used as necessary, and can be applied to any cable 10a that does not have the support wire portion 14 from the beginning, as shown in FIG. Since the optical fiber cable 10a that does not have the support line portion 14 has the same configuration as that of FIG. 1A except that the support line portion 14 is not provided, detailed description thereof is omitted.

  FIG. 1C is a diagram showing a state in which the optical fiber cable having the above-described configuration is cut, and shows an example of the optical fiber cable 10a in a form in which the support wire portion 14 is removed. In order to take out the optical fiber core line 11, for example, cutting blades 20 a and 20 b of a simple tool such as a nipper are inserted into notches 15 on both sides provided on one tension member side of the cable jacket 13. Make a cut. In this case, the notch 15 has a function of guiding the positioning and cutting of the cutting blades 20a and 20b, and is formed outside so as not to hit the optical fiber core line 11.

  For this reason, the optical fiber core wire is not damaged by the cutting blades 20a and 20b, and the cutting blades 20a and 20b are guided by the notch 15 and cut toward the overhanging region S of the wide peeling tape 16a. Further, the cutting blades 20a and 20b are inserted from both side surfaces of the cable jacket 13, and are cut so as to sandwich one release tape 16a from both surfaces. Thereby, the cable jacket 13 can be completely cut along with the peeling tape 16a along the cutting axis X.

  When the peeling tape 16a is formed of a material harder than the cable jacket 13, when the cutting blades 20a and 20b abut against the peeling tape 16a, the cutting force becomes large or the cutting becomes difficult. The cutting may be stopped at this point. If a cut is made in the notch 15 on one tension member side, the cut is made in the same manner on the other tension member side. The incision by the cutting blades 20a and 20b such as nippers is a starting end for manually tearing the cable along the longitudinal direction into the notch 15 of the cable jacket 13 by continuously inserting several portions in the longitudinal direction of the cable. Short rifts can be formed.

  FIG. 1D shows a state where the optical fiber core wire in the cable is taken out. In FIG. 1 (C), after a tearing slit is formed by the cutting blades 20a and 20b, the split portions 13a and 13b on the end side including the tension member 12 are opened to the left and right from the split portion. By opening 13c and 13d up and down, the cable jacket 13 is torn in the longitudinal direction. By this cable tearing, the cable jacket 13 is divided into four parts, ie, divided parts 13a and 13b on the end side including the tension member 12 and divided parts 13c and 13d on the side surface side. Moreover, even if the peeling tapes 16a and 16b are not adhered to the cable jacket 13 or are adhered, the adhesive force is weak, so that the separation tapes 13a to 13d can be easily separated.

  In addition, although the optical fiber core wire located in the both ends of the optical fiber core line 11 may be partly in contact with the cable jacket 13 and lightly bonded, it is not surrounded by the resin material. It can be easily separated from the cable jacket 13. Further, since the cable jacket 13 is covered in a contact state between the peeling tapes 16 a and 16 b and the optical fiber core line 11, the resin material of the cable jacket 13 is placed in the optical fiber core line 11. It does not enter, is in a non-adhesive state, and is easily separated. If the cutting blades 20a and 20b are only inserted, the separation is partially insufficient, and if the separation is not complete, a hand or a tool is used as an auxiliary, but the auxiliary tearing force is slightly increased. Therefore, it is not a problem at the time of separation.

  As a result, in order to take out the optical fiber core wire in the optical fiber cable, it is only necessary to make cuts at four points along the longitudinal direction of the cable. As shown in FIG. There is no need to split. Therefore, during optical fiber branching in a live line state, momentary fluctuations in the loss of the optical fiber and an increase in loss due to bending can be suppressed, and light can be transmitted without greatly affecting the transmission signal. A fiber cable can be branched.

  FIG. 2 is a diagram for explaining the second embodiment, FIG. 2 (A) is a diagram showing an example of an optical fiber cable according to the present invention, and FIG. 2 (B) is a diagram showing a cable having no support line portion. . In the figure, reference numerals 15a and 15b denote notches, and the other reference numerals are the same as those used in FIG.

  The optical fiber cable 10 according to FIG. 2A has tension members 12 arranged in parallel on both sides of the optical fiber core line 11 in the same manner as shown in FIG. The structure has a structure in which the tensile strength with respect to the optical fiber core array 11 is increased. The optical fiber core line 11 is positioned on both side surfaces of the cable jacket 13 on the side where the tension member 12 is not disposed so as to be positioned between the tension member 12 and the optical fiber core line 11 on both ends. V-shaped notches 15a and 15b are provided with a gap M larger than the width D of the first. As will be described later, the notch 15a is shallow and the notch 15b is deeply formed.

  A pair of release tapes 16 a and 16 b that are not adhesive or are easily peeled from the cable jacket 13 on both sides of the optical fiber core line 11 are provided on both sides of the optical fiber core line 11. Arranged. One release tape 16a of the pair of release tapes is wider than the other release tape 16b. The pair of release tapes 16a and 16b are arranged so as to come into contact with the arrangement surface of the optical fiber core line 11 and completely cover both sides thereof, and together with the optical fiber core line 11 and the tension member 12, the outside of the cable. It is covered by the cover 13 at once.

  For example, a tape having the same width as the width D of the optical fiber core line 11 is used as the release tape 16b of the pair of release tapes. The release tape 16a wider than the width of the release tape 16b covers one arrangement surface of the optical fiber core line 11, and both sides protrude in the width direction from both ends of the release tape 16b and the optical fiber core line 11. Thus, it has an overhanging region S that does not overlap the peeling tape 16b and the optical fiber core line 11. The overhang region S is positioned between the tension members 12 on both sides intersecting the cutting axis X of the notch 15 and the optical fiber core line 11.

As shown in FIG. 2 (A), the optical fiber cable 10 is provided with a removable support wire portion 14 connected by a narrow neck portion 14a at one end of the cable jacket 13 as a self-supporting overhead cable. Shown in a shape suitable for use. The support line portion 14 can be removed and used as necessary, and can be applied to any optical fiber cable 10a that does not have the support line portion 14 from the beginning, as shown in FIG. Since the optical fiber cable 10a that does not have the support line portion 14 has the same configuration as that in FIG. 2A except that the support line portion 14 is not provided, detailed description thereof is omitted.
In addition, about the material of the each part which comprises the optical fiber cables 10 and 10a, a material, etc., since the thing similar to having demonstrated in FIG. 1 can be used, description here is abbreviate | omitted.

In the example of FIG. 2, the depths of the notches 15a and 15b facing each other are made different so that the distances L1 and L2 between the peeling tape 16 and the tip of the notch are substantially equal. Note that the intervals L1 and L2 do not have to be completely coincident with each other as long as they are close to each other. The pair of peeling tapes 16 arranged with the optical fiber core line 11 interposed therebetween are positioned slightly displaced from the center of the cable jacket 13 to the respective side surfaces. For this reason, if the distance from the side surface of the cable jacket 13 to the overhang region S of the peeling tape 16a is different, and the depths of the notches 15 are all the same as in the example of FIG. The distances L1 and L2 with the peeling tape 16a may be greatly different.

  In this case, as shown in FIG. 1C, the cutting blades 20a and 20b that are simultaneously inserted from both side surfaces of the cable jacket 13 have different cutting amounts toward the peeling tape 16a between the cutting blades 20a and 20b. It will be. As a result, when the hardness of the peeling tape 16a is harder than that of the cable jacket 13, since the timing at which the cutting blade 20b reaches the peeling tape 16 is somewhat delayed from the cutting blade 20a, the cutting position may be shifted.

  However, as shown in FIG. 2, the depth of the notch 15b on the side where the distance between the side surface of the cable jacket 13 and the peeling tape 16a is large is increased, and the distance L2 between the peeling tape 16a and the notch tip is set to the opposite side. By making the distance L1 substantially equal to the distance L1 between the peeling tape 16a and the tip of the notch 15a, the difference in the cutting force by the cutting blade can be made small or equal. As a result, the cutting by the cutting blades 20a and 20b can be performed with a good balance, and a clean tear can be formed.

  As described above, one of the pair of peeling tapes sandwiching the optical fiber core line is widened, and an overhanging area that does not overlap the other peeling tape and the optical fiber core line is provided, and the cutting blade reaches the part of the overhanging area. By cutting in this way, it is possible to form a notch serving as a tearing start end that allows the cable to be manually torn in the longitudinal direction. This cutting can be performed with a simple tool such as a nipper, and it is not necessary to use an expensive dedicated tool, so that the working efficiency can be improved. In addition, the optical fiber core can be easily taken out without greatly tearing the cable jacket, and the increase in loss due to loss fluctuation and bending of the optical fiber can be suppressed, thus realizing a branch operation in a live state. be able to.

  Further, by forming the release tape with a hard material, even if a ridge pierces the laying tube in the cable from a notch having a relatively thin coating thickness on the optical fiber core line 11, Further, the optical fiber core wire can be prevented from being damaged by the hard release tape.

It is a figure explaining the 1st Embodiment of this invention. It is a figure explaining the 2nd Embodiment of this invention. It is a figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,10a ... Optical fiber cable, 11 ... Optical fiber core line, 12 ... Tension member, 13 ... Cable jacket, 14 ... Support wire part, 14a ... Neck part 15, 15, 15a, 15b ... Notch, 16a, 16b ... Exfoliation Tape, 20a, 20b ... cutting blade.

Claims (3)

An optical fiber cable in which tension members are arranged in parallel on both ends of the optical fiber core line and covered with a cable jacket,
On both sides where the tension member of the cable jacket is not arranged, notches for cutting are provided between the optical fiber core line and the tension members on both sides,
A pair of release tapes are arranged so as to contact the optical fiber array and completely cover and sandwich both sides of the array surface ,
One of the pair of release tapes has an extension region that protrudes from both sides in the width direction of the other release tape and the optical fiber array, and the notch cutting axis is located in the extension region. Features an optical fiber cable. The notches are formed so that the notches on both sides of the tape have different depths so that the distance between the notch tips facing each other and the peeling tape in the overhanging region is closer on both sides of the tape. The optical fiber cable according to claim 1.   The optical fiber cable according to claim 1, wherein the release tape is harder than the cable jacket.

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