JP2006003689A - Optical drop cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical drop cable having superior performance, capable of readily taking-out coated optical fiber tape from a cable jacket, even in large-sized coated optical fiber or coated optical fiber tape. <P>SOLUTION: The optical drop cable 101 is provided with a coated optical fiber 11, tension members 12a, 12b arranged in parallel with the coated optical fiber 11 and a jacket 13 applied collectively on their outer periphery by extrusion. A pair of principal notches 14a, 14b of large width are disposed on both side surfaces of the jacket 13. Further, subsidiary notches 15a, 15b extended to such a cable width direction that the distance from the top ends thereof to the coated optical fiber 11 is 0.18 to 0.35 mm, and the extension lines of the top ends fall into the range from the center of the coated optical fiber 11 to L/4-3L/4 are disposed on the respective principal notches 14a, 14b so as to be located close to the lower end on one side principal notch 14a and close to the upper end on the other principal notch 14b, respectively, wherein L is the diameter of the coated optical fiber 11 or the size of the cable height direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical drop cable used for lead-in wiring from a wiring system cable installed in an aerial or underground to a general subscriber's house.

  As a so-called optical drop cable used to draw into a general subscriber's home from a wiring system cable installed in an aerial or underground, steel wire or FRP on one or two sides of one or two single-core optical fibers (Glass fiber reinforced plastic) and other strength members are placed and covered with a resin such as polyethylene (underground light drop cable), or such a cable is further integrated with a support wire made of steel. (Aerial optical drop cable) is known (for example, see Patent Document 1).

  FIG. 3 shows an example of an aerial optical drop cable. As shown in the figure, this optical drop cable has a single-strand optical fiber core 1 sandwiched between tension members 2 and 2 above and below it, and a support wire 3 disposed above them. The outer periphery 4 is covered with a resin such as polyethylene at the same time, and the outer cover 4 is provided. A connecting portion (neck portion) 7 that divides the cable into a supporting wire portion 5 and a cable portion 6 is provided between the supporting wire 3 and the strength member 2 of the cable. At notches 8 and 8 for tearing are provided at substantially central portions of both side surfaces.

  In such an optical drop cable, since the support line 3 is provided, the aerial laying is possible, and since the connection part 7 is provided, the cable part 6 is separated from the support line part 5. Can be wired indoors. Furthermore, since the notch 8 for tearing is provided, it is possible to easily take out the optical fiber core wire 1 by tearing the jacket 4 in the width direction of the cable at these notch 8 portions.

  By the way, recently, in this type of optical drop cable, a coating for protecting the optical fiber is used as an optical fiber core so that the optical fiber core is not broken during terminal processing or intermediate branching. The one formed into the meat or the one coated with a coating on the outer periphery of the optical fiber core wire has come to be used. Also, in order to respond to the increase in demand, a multi-fiber ribbon optical fiber in which a plurality of optical fibers are arranged in parallel and the outer periphery thereof is collectively covered has come to be used in many cases. With the increase in diameter of such optical fiber cores and the increase in use of tape-shaped optical fiber cores, the following problems have occurred.

That is, in the conventional optical drop cable in which one or two small-diameter single-core optical fibers are embedded, as described above, the jacket 4 is formed by the notch 8 portions provided at substantially the center of both side surfaces of the jacket 4. The optical fiber core wire 1 can be easily taken out by tearing. However, when a single-core optical fiber or a tape-shaped optical fiber whose diameter has been increased is used, the contact area with the jacket 4 increases, so even if the jacket 4 is torn at the notch 8 portion, The optical fiber core or the tape-shaped optical fiber core remains in close contact with one of the two outer sheaths, and the single core optical fiber core with a small diameter taken out from the outer sheath 4 It wasn't as easy as it was.
JP 2002-365499 A

  The present invention has been made in response to the above-described problems of the prior art, and can be easily taken out from the cable jacket even when the diameter of the optical fiber core or the tape-shaped optical fiber is increased. An object of the present invention is to provide an optical drop cable with excellent take-out property.

  In order to achieve the above object, an optical drop cable according to the first aspect of the present invention includes an optical fiber core having a circular or rectangular cross section, and a parallel upper and / or lower side of the optical fiber core. An optical drop cable comprising an arranged tensile body and a jacket which is extrusion-coated on the outer periphery thereof, and a pair of wide main notches provided on both side surfaces of the jacket, Each of the main notches has a distance from the tip to the optical fiber core of 0.18 to 0.35 mm, and an extension of the tip extends from the center of the optical fiber core to L / 4 to 3L / 4 (here , L is a secondary notch extending in the cable width direction such that it is in the range of the diameter of the optical fiber core wire or the cable height direction, one main notch is closer to its upper end and the other main notch is its Near the bottom, each It is characterized in that the digits.

  An optical drop cable according to a second aspect of the present invention includes an optical fiber core, tensile strength members arranged in parallel above and / or below the optical fiber core, and a bundle of the same around the outer periphery thereof. A cable portion having a first outer cover coated by extrusion, a support line portion formed by applying a second outer cover to the outer periphery of the support wire, and the first and second outer jackets. An optical drop cable including a connecting portion for connecting the cable portion and the support wire portion, and a pair of wide main notches provided on both side surfaces of the first jacket, A distance from the tip of the main notch to the optical fiber core is 0.18 to 0.35 mm, and an extension of the tip is L / 4 to 3L / 4 from the center of the optical fiber core (where L Is the range of the optical fiber core diameter or cable height direction) The secondary notches extending certain such cable the width direction, in the one of the main notch its upper end close, the other main notch at its lower end closer, is characterized in that provided respectively.

  The invention described in claim 3 is the optical drop cable according to claim 1 or 2, wherein L is 0.4 mm or more.

  According to a fourth aspect of the present invention, in the optical drop cable according to the first or second aspect, the optical fiber core is a circular optical fiber core having a diameter of 0.4 mm or more, or a major axis of 0.5 mm. As described above, the optical fiber tape core wire has a long diameter surface arranged in parallel with the cable height direction.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is the optical fiber core wire and tape-shaped optical fiber core wire which were enlarged in diameter, the optical drop cable optical drop cable excellent in the core wire extraction property which can be taken out easily from a cable jacket Can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A and 1B are diagrams for explaining an embodiment of an optical drop cable according to the present invention. FIG. 1A is a diagram showing an overall cross-sectional structure, and FIG. 1B is a diagram showing an enlarged main part thereof.

  As shown to (a) of FIG. 1, the optical drop cable 101 of this embodiment is comprised from the cable part 10, the support wire | line part 20, and the connection part 30 which connects these.

  The cable portion 10 is a single-core optical fiber core wire 11 having a circular cross section and is spaced above and below the single-core optical fiber core wire 11 so that the centers thereof are located on the same plane. Tensile members 12a and 12b (hereinafter referred to as the tensile member 12a above the single-core optical fiber core wire 11) made of steel wires, FRP (glass fiber reinforced plastic) and the like arranged in parallel are used as the first tensile member and the single-core optical fiber core. The tensile body 12b below the line 11 is referred to as a second tensile body.) And a jacket 13 made of a plastic such as polyethylene or vinyl chloride resin, which is collectively extrusion-coated on the outside thereof. The jacket 13 has a rectangular cross section.

  The support wire portion 20 includes a support wire 21 made of a steel wire and the like, and a sheath 22 that is formed by integrally extruding the outer periphery 13 of the cable portion 10 and the connecting portion 30 on the outer periphery thereof. The covering 22 has a circular cross section.

  On the surface of the jacket 13 on both sides of the portion of the cable portion 10 where the single-core optical fiber core 11 is located, the cross section is an inverted trapezoidal shape, and both ends are approximately at the positions of the upper end and the lower end of the single-core optical fiber core 11, respectively. The main notches 14a and 14b are so wide as to reach each other, and the main notches 14a and 14b are respectively provided with sub-notches 15a and 15b extending in the cable width direction. Specifically, the sub-notch 15a (hereinafter referred to as the first sub-notch) is the lower end of one main notch 14a (hereinafter referred to as the first main notch), that is, the second strength member. The sub notch 15b (hereinafter referred to as the second sub notch) is provided at the end near 12b, and is the upper end of the other main notch 14b (hereinafter referred to as the second main notch), that is, , Provided at the end near the first strength member 12a.

As shown in FIG. 1B, the first sub-notch 15a has a distance a from the tip to the single-core optical fiber 11 of 0.18 to 0.35 mm, The distance b from the center of the single-core optical fiber 11 is L / 4 to 3L / 4 (where L is the diameter of the single-core optical fiber 11), that is, the extension line at the tip is single. It provided from the center of the core optical fibers 11 to be in the range of L / 4~3L _1/4. Although not shown in the drawings, the second sub-notch 15b has a distance of 0.18 to 0.35 mm from the tip to the single-core optical fiber 11 as well as the first sub-notch 15a. The distance b from the center of the single-core optical fiber core 11 is L / 4 to 3L / 4, that is, the extension line at the tip is L / 4 from the center of the single-core optical fiber core 11. It is provided to be in a range of ˜3L / 4. The shape of the first and second sub-notches 16a and 16b is not particularly limited, and may be a simple cut or a narrow groove.

  The single-core optical fiber core 11 is not particularly limited, and the outer periphery of the optical fiber is coated with a silicone resin, an ultraviolet curable resin, or the like, and the outer periphery of the thermoplastic elastomer further includes a nylon resin or a colorant. For example, a polybutylene naphthalate thermoplastic elastomer or a polybutylene terephthalate thermoplastic elastomer is used. Further, it is also possible to use a coating made of nylon resin or the like and further coated with a thermoplastic resin such as polyethylene or vinyl chloride resin via a tensile fiber layer (usually referred to as an optical fiber cord). Examples of the tensile strength fibers constituting the tensile strength fiber layer include aramid fibers such as poly-p-phenylene terephthalamide fibers, polyester fibers such as polyethylene terephthalate fibers, and nylon fibers.

  Moreover, as a material which comprises the jacket 13 of the cable part 10, the coating | cover 22 of the support wire part 20, and the connection part 30, in addition to polyethylene and a vinyl chloride resin, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate Copolymers, ethylene-propylene copolymers and the like are used. These resins may contain a flame retardant, a colorant, and the like.

  Further, as materials constituting the first and second strength members 13a and 13b, in addition to steel wires and FRP, aramid fibers such as poly-p-phenylene terephthalamide fibers, polyester fibers such as polyethylene terephthalate fibers, nylon Examples thereof include fibers and composite materials obtained by converging and binding these fibers with a polyester-acrylate resin or the like.

  In the optical drop cable 101 of the present embodiment, wide main notches 14a and 14b are provided on both side surfaces of the jacket 13 of the cable portion 10 with the single-core optical fiber core 11 sandwiched therebetween, and each of these main notches. 14a and 14b, the distance from the tip to the single-core optical fiber core 11 is 0.18 to 0.35 mm, and the extension of the tip is L / 4 to 3L / 4 from the center of the single-core optical fiber core 11. Sub-notches 15a and 15b extending in the cable width direction as shown in FIG. 3 are provided near one lower end of the main notch 14a and closer to the upper end of the other main notch 14b. In this way, not only the sub-notches 15a and 15b are provided, but also the length and position of the sub-notches 15a and 15b are specified. Even if the single-core optical fiber 11 has a large diameter and is torn along a line connecting the tips of the sub-notches 15a and 15b located diagonally across the line 11, it can be easily taken out. . In addition, the provision of the sub-notches 15a and 15b may cause a crack in the jacket 13 due to a change in the environmental temperature. However, as will be apparent from the examples described later, this problem occurs. Nor.

  The present invention is not limited to the embodiment described above. For example, as shown in FIG. 2, an optical fiber tape core 16 may be used instead of the single optical fiber core 11. . The optical fiber cable 102 shown in FIG. 2 has four optical fiber strands 16a arranged in parallel instead of the single-core optical fiber core 11 in the first embodiment, and a collective coating 16b is applied to the outer periphery thereof. The core optical fiber tape core wire 16 is arranged with its long diameter surface parallel to the cable height direction. In this case, as shown in FIG. 2B, L that defines the positions of the sub-notches 15a and 15b is the diameter and the major axis of the four-core optical fiber ribbon 16 in the cable height direction. That is, in this example, the first sub-notch 15a has a distance a from the tip to the optical fiber ribbon 16 of 0.18 to 0.35 mm, and the optical fiber tape 16 of the extension of the tip 16 The distance b from the center is set to be L / 4 to 3L / 4 (where L is the long diameter of the optical fiber ribbon 16). Although not shown in the drawings, the second sub-notch 15b has a distance of 0.18 to 0.35 mm from the tip to the optical fiber ribbon 16 as well as the first sub-notch 15a. The distance b from the center of the optical fiber ribbon 16 of the extension line is provided to be L / 4 to 3L / 4.

  Also in such an optical drop cable 102, when the outer cover 13 is torn at the main notches 14a and 14b, the tips of the sub-notches 15a and 15b positioned diagonally across the optical fiber ribbon 16 are connected. The optical fiber ribbon 16 can be easily removed by tearing along the line. Further, the occurrence of cracks in the outer jacket 13 due to changes in the environmental temperature is also prevented.

  Although not shown, the optical drop cable of the present invention may be configured only by the cable portion 10. Each of the optical drop cables 101 and 102 shown in FIGS. 1 and 2 is used as an aerial optical drop cable, whereas an optical drop cable composed only of the cable portion 10 is an underground optical drop cable. Used as.

  When the present invention is applied to an optical drop cable in which a single-core optical fiber or an optical fiber tape having an L defined as described above is 0.4 mm or more, it is possible to obtain a remarkable effect. A single-core optical fiber core having a circular cross section with a diameter of 0.4 mm or more or an optical drop cable having an embedded optical fiber tape core with a major axis of 0.5 mm or more and a major axis surface parallel to the cable height direction. When applied, a particularly remarkable effect is obtained.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Examples 1-3
The outer diameter of the single-core optical fiber core 11 coated with Hytrel 6347 (trade name of polyester elastomer, manufactured by Toray DuPont) on the outer periphery of a single-core UV-curable resin-coated optical fiber having an outer diameter of 0.25 mm An optical drop cable having a structure shown in FIG. 1 was manufactured using a 0.4 mm single-core optical fiber. The tensile members 12a and 12b were FRP rods having an outer diameter of 0.4 mm, and the support wire 21 was a single steel wire having an outer diameter of 1.2 mm.

  First, one single-core optical fiber core wire 11, two strength members 12a and 12b, and a support wire 21 are introduced into an extruder in a state of being arranged in parallel as shown in FIG. After non-halogen flame retardant polyethylene (trade name NUC9739 manufactured by Nippon Unicar Co., Ltd.) is extruded and coated, the main notches 14a and 14b on both sides of the cable portion 10 are cut for the sub notches 15a and 15b, and the overall width is 2.0 mm. The same height is 5.0 mm, the width of the main notch of the cable part 10 is 0.5 mm, the maximum part is 0.8 mm, the same depth is 0.8 mm, and a (the tip of each sub-notch 15a, 15b) Table 1 shows the optical drop cables in which the distance from the center of the single-core optical fiber 11 to the single-core optical fiber 11) and b (distance from the center of the single-core optical fiber 11) The And elephants.

Examples 4 and 5
As the single-core optical fiber core wire 11, the outer periphery of a single-core ultraviolet curable resin-coated optical fiber strand having an outer diameter of 0.25 mm is coated with nylon resin to form a nylon core wire having an outer diameter of 0.9 mm. Poly-p-phenylene terephthalamide fiber (Kevlar 49: trademark; 1140 denier double twist) is vertically attached to the outer periphery of the wire and introduced into the extruder, and soft vinyl chloride resin (Riken Technos Co., Ltd. An optical drop cable having the structure shown in FIG. 1 was manufactured using an optical fiber cord having an outer diameter of 1.5 mm obtained by extrusion-coating V120A) into a pipe shape having a thickness of 0.25 mm. The tensile members 12a and 12b were FRP rods having an outer diameter of 0.4 mm, and the support wire 21 was a single steel wire having an outer diameter of 1.2 mm.

  First, one single-core optical fiber core wire 11, two strength members 12a and 12b, and a support wire 21 are introduced into an extruder in a state of being arranged in parallel as shown in FIG. After non-halogen flame retardant polyethylene (trade name NUC9739, manufactured by Nihon Unicar Co., Ltd.) is batch-extruded, cuts for the sub notches 15a and 15b are made in the main notches 14a and 14b on both sides of the cable portion 10, and the overall width is 2.5 mm. The same height is 5.5 mm, the main notch width of the cable portion 10 is 1.5 mm, the maximum portion is 1.8 mm, the depth is 0.3 mm, and a (the tip of each sub-notch 15a, 15b) Table 1 shows the optical drop cables in which the distance from the center of the single-core optical fiber 11 to the single-core optical fiber 11) and b (distance from the center of the single-core optical fiber 11) The And elephants.

Example 6
As the optical fiber ribbon 16, four single-core ultraviolet curable resin-coated optical fiber strands having an outer diameter of 0.25 mm are juxtaposed, and the outer diameter is collectively covered with ultraviolet curable resin. An optical drop cable having a structure shown in FIG. 2 was manufactured using a 3 mm optical fiber ribbon. The tensile members 12a and 12b were FRP rods having an outer diameter of 0.4 mm, and the support wire 21 was a single steel wire having an outer diameter of 1.2 mm.

  First, one optical fiber tape core wire 16, two strength members 12a and 12b, and a support wire 21 are introduced into an extruder in a state of being arranged in parallel as shown in FIG. After flame-extrusion polyethylene (trade name NUC9739 manufactured by Nihon Unicar Co., Ltd.) is batch-extruded, V-grooves for the sub-notches 15a and 15b are put in the main notches 14a and 14b on both sides of the cable part 10, and the overall width is 2.0 mm The same height is 6.0 mm, the main notch width of the cable portion 10 is a minimum portion 1.1 mm, the maximum portion 1.5 mm, and the depth is 0.5 mm, and a (tips of the sub notches 15a and 15b) Table 1 shows the optical drop cables in which the distance from the optical fiber tape core 16) and b (the distance from the center of the optical fiber tape 16 of the extension of each sub-notch 15a, 15b) are shown in Table 1, respectively. It was produced.

  About each obtained optical drop cable, it tried to take out from the jacket 13 of the single core optical fiber core wire 11 or the optical fiber tape core wire 16, and the extraction property was evaluated. Moreover, in order to evaluate the mechanical strength of the cable part 10, after performing the heat cycle test which made -30 degreeC- + 70 degreeC 3 cycles, and holding time of each temperature for 6 hours to each obtained optical drop cable, The cable was wound around a drum and examined for the occurrence of cracks in the cable jacket 13. These results are shown in Table 1.

Table 1 also shows an optical drop cable having the same configuration as that of Example 1 except that each value of a and b deviates from the range according to the present invention for comparison with the present invention. The results of the characteristic evaluation are also shown as Comparative Examples 1 and 2.

  As is clear from Table 1, in the optical drop cable according to the present invention, the take-out property of the core wire was good and the result of the heat cycle test was good, whereas in Comparative Example 1, the take-out property of the core wire was good. However, when wound on the drum after the heat cycle, cracks were observed in the cable jacket, and in Comparative Example 2, the result of the heat cycle test was good, The wire pick-up property was poor.

It is a figure explaining one Embodiment of the optical drop cable of this invention, (a) is sectional drawing of the whole, (b) is the principal part expanded sectional view. It is a figure explaining other embodiment of the optical drop cable of this invention, (a) is sectional drawing of the whole, (b) is the principal part expanded sectional view. Sectional drawing which shows an example of the conventional optical drop cable.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cable part, 11 ... Single core optical fiber, 13 ... Outer sheath, 14a, 14b ... Main notch, 15a, 15b ... Sub notch, 16 ... Optical fiber tape core, 21 ... Support wire, 22 ... Covering, 30 ... Connecting part, 101, 102 ... Optical drop cable

Claims (4)

An optical fiber core having a circular or rectangular cross-section, a tensile body arranged in parallel above and / or below the optical fiber core, and a jacket that is collectively covered with extrusion coating on the outer periphery thereof. An optical drop cable provided,
A pair of wide main notches are provided on both side surfaces of the jacket, and the distance from the tip of the main notch to the optical fiber core is 0.18 to 0.35 mm. Is a sub-notch extending in the cable width direction such that L is in the range of L / 4 to 3L / 4 (where L is the diameter of the optical fiber core or the diameter in the cable height direction) from the center of the optical fiber core. An optical drop cable characterized in that one main notch is provided near its upper end and the other main notch is provided near its lower end. A cable section comprising: an optical fiber core; a tensile body disposed in parallel above and / or below the optical fiber core; and a first outer jacket collectively coated on the outer periphery of the tensile body. A support wire portion formed by applying a second jacket to the outer periphery of the support wire; and a connecting portion that is provided integrally with the first and second jackets and connects the cable portion and the support wire portion. An optical drop cable provided,
A pair of wide main notches are provided on both side surfaces of the first jacket, and the distance from the tip of the main notch to the optical fiber core is 0.18 to 0.35 mm. A secondary notch extending in the cable width direction such that the extension line of the optical fiber is in the range of L / 4 to 3L / 4 from the center of the optical fiber core, one main notch is closer to the upper end and the other main notch Is an optical drop cable that is provided near the lower end.   The optical drop cable according to claim 1 or 2, wherein L is 0.4 mm or more.   The optical fiber core is an optical fiber core having a circular cross section with a diameter of 0.4 mm or more, or an optical fiber tape core having a major axis of 0.5 mm or more and a major axis surface disposed in parallel with the cable height direction. The optical drop cable according to claim 1 or 2, wherein

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