JP4246717B2 - Anti-light transmission cable - Google Patents

Description

  The present invention relates to an optical drop cable that draws an optical cable from an aerial optical wiring cable to a user's house through a closure, and more particularly to an optical drop cable that prevents damage caused by insect laying tube insertion.

  Some insects have the habit of inserting an oviduct directly into the bark and laying eggs, and the habit of attaching a bite to the bark and laying eggs in the bark through this moth, etc. Insects with such habits, especially the bearfish with a strong egg-laying tube, lay eggs on the outer sheath of the optical drop cable, causing an accident that damages or breaks the optical fiber core in the optical drop cable. .

  When the above accident was observed, a V-shaped groove was formed in the longitudinal direction of the surface of the protective coating in order to make it easy to peel off the protective coating having a flat or oval cross section. It has been found that the laying tube is inserted and its tip reaches the optical fiber core and is damaged or disconnected.

The following patent documents can be cited as examples of such accident prevention measures.
JP 2002-090593 A (summary and selection drawing) JP 2002-328276 A (summary and selection drawing)

  In any of the inventions according to the above-mentioned patent documents, the tip of the egg-laying tube is prevented from reaching the optical fiber core by shifting the V-shaped concave groove from right to left from right above the optical fiber core (FIG. 2). However, as a result of the verification test, it was found that sufficient effects could not be obtained.

  In addition, since the material used for the protective coating (outer coating) is vinyl chloride or low density polyethylene, the one described in the above patent document is soft and has a flat, oval and deep V-shaped recess. Since the grooves are formed, insects (spiders) are likely to stop and the laying tube is easily inserted.

  Furthermore, since the above materials have low mechanical strength and a large friction coefficient, slipping during laying (pulling) work is poor, and a load is applied to the optical fiber core wire, which may lead to a decrease in transmission characteristics.

  In addition, as shown in FIG. 4, the applicant of the present invention arranged two hexagons with a slightly vertical cross section in parallel as shown in FIG. A drop cable was produced on a line connecting the core wire and the tension member and on the outer side of the protective coating, and the outer cover was formed with the protective coating via a bridge.

  This prototype is a flat V-shaped groove with a flat bottom, making it difficult to insert the egg-laying tube. As a result of the verification test, it was found that sufficient effects could not be obtained. .

  In view of the above, the present invention firstly makes it difficult for insects, in particular, bearfish to stop, and makes it difficult to insert the laying tube, and secondly, when pulling the optical drop cable into the user's home, It is an object of the present invention to provide an optical drop cable in which the applied external pressure is made as small as possible to prevent deterioration of transmission characteristics.

  In order to solve the above-described problems, the present invention provides an optical fiber in which an optical fiber core wire is disposed at the center, tension members are disposed on both sides of the optical fiber, and a protective coating having a circular or elliptical cross section is provided on both. In the cable, the ratio of the major axis / minor axis of the protective coating is 1 to 2, and a V-shaped groove is formed in the surface length direction of the protective coating. A support gap is arranged on the extended line of the line connecting the optical fiber core wire and the tension member and outside the protective coating, and the outer cover is placed on the support line and the bridge is provided. The V-shaped groove is formed at the midpoint of the line connecting the optical fiber core wire and the tension member, and the valley bottom has an arc shape on the surface of the protective coating on the orthogonal line. Slightly at the intersection of the valley and the outer peripheral surface It is a V-shaped concave groove having a rounded shape, the depth of the V-shaped concave groove is 1/12 to 1/7 of the minor axis of the protective coating, the radius of the arc is 1/18 of the minor axis of the protective coating. The material is a low friction / flame retardant polyurethane composition having a hardness of 90 (HDA) or more and a coefficient of friction with respect to vinyl chloride of 0.2 or less.

  According to the present invention configured as described above, the outer shape of the light-proof optical transmission cable body is circular or elliptical in cross section, and the valley shape and depth of the V-shaped groove are specified, and the valley surface of the V-shaped groove. By providing a minute round at the intersection of the outer peripheral surface and the outer peripheral surface, it is difficult for insects (claws) to stop, and it is difficult to pierce the laying tube, and the mechanical strength can be increased.

  In addition, by selecting a protective coating material with a low coefficient of friction, the pull-in operation is facilitated, the load on the optical fiber core is reduced during the pull-in operation, and the transmission characteristics are prevented from deteriorating. By providing a gap between the fiber core and the protective coating, the optical fiber core is not loaded even when a load is applied to the protective coating, and the optical fiber core moves within the protective coating. The tip of the lens will come off the optical fiber core wire.

  In the means for solving the above problems, the ratio of the major axis / minor axis of the protective coating is set to 1 or 2 because the relation between the major axis and the minor axis is reversed when the ratio is 1 or less. This is because there is a problem, and when it is 2 or more, it becomes a long ellipse and it becomes difficult to bend the wiring, particularly in the long axis direction.

  In addition, the depth of the V-shaped groove is set to 1/12 to 1/7 of the short axis of the protective coating. When the depth is 1/12 or less (the groove is shallow), it is difficult to tear the protective coating in wiring work. This is because the spawning tube of the spider becomes easy to pierce at 1/7 or more. Furthermore, the radius (arc) of the valley bottom of the V-shaped groove is set to 1/18 to 1/8 of the short axis of the protective coating. This is because there is a risk that the egg-laying tube reaches the optical fiber core wire, and if it is 1/8 or more, the tearing effect of the protective coating is lowered.

  The protective coating is formed of a low friction / flame retardant polyurethane composition having a hardness of 90 (HDA) or more and a friction coefficient of 0.2 or less with respect to vinyl chloride. The purpose is to prevent the transmission characteristics from being lowered due to the addition of tension, and to prevent the spread of fire using a cable as a medium.

  Next, embodiments of the present invention will be described with reference to the drawings. A drop cable 10 according to the present invention has an optical fiber core wire 11 at the center and tension members 12 spaced on both sides thereof, and a protective coating 15 having a circular or elliptical cross section is provided on both. At the midpoint of the line connecting the optical fiber core wire 11 and the tension member 12, the valley bottom has an arc shape in the surface length direction of the protective coating 15 on the orthogonal line, and the valley surface and the outer peripheral surface of the protective coating are A V-shaped groove 14 having a minute rounded radius R is provided at the intersecting portion, and a minute gap G is provided between the optical fiber core wire 11 and the protective coating 15.

  Further, as another embodiment, an optical fiber core wire (including an optical fiber tape core wire) 11 and tension members 12 are arranged on both sides of the optical fiber core wire, and a circular cross section or an elliptical shape is formed on both. And a support wire 13 (galvanized steel wire) is disposed outside the protective coating 15 on the extended line of the line connecting the optical fiber core wire 11 and the tension member 12, and this support wire An outer cover 16 is integrally formed with the protective coating 15 on the bridge 13 via the bridge 17, and the protective coating on an orthogonal line at the midpoint of the line connecting the optical fiber core wire 11 and the tension member 12. 15 is provided with a V-shaped concave groove 14 having a minute radius R at a portion where the bottom of the valley has an arc shape and the valley surface and the outer peripheral surface of the protective coating intersect, and the optical fiber core 11 and the protective coating Between 15 and a minute gap Group G is provided.

  FIG. 1A shows a first embodiment, 11 is a single-core optical fiber core wire having an outer diameter of 0.25 mm, 12 is a tension member of an aramid fiber reinforced plastic cord having a diameter of 0.45 mmφ, A protective coating 15 having an outer diameter of 2.0 mmφ is formed on the tension member 12 with a low friction / flame retardant polyurethane composition.

  In forming the protective coating 15, the tip of the nipple for supporting and passing the optical fiber core wire 11 is slightly protruded from the end surface of the die, and a so-called pipe extrusion method is adopted, and the optical fiber core wire 11 and the protective coating 15 are interposed. V-shaped concave groove in which a minute gap G of 0.2 to 0.5 mm is formed, a valley bottom is in an arc shape in the surface length direction of the protective coating 15, and a minute radius R is formed at a portion where the valley surface and the outer peripheral surface intersect 14 is provided.

  Here, the minute gap G between the optical fiber core wire 11 and the protective coating 15 is set to 0.2 to 0.5 mm. If the gap is less than 0.2 mm, the effect of avoiding the insertion of the laying tube cannot be obtained and exceeds 0.5 mm. This is because the thickness of the V-shaped groove to the bottom of the valley becomes thin and the protective coating 15 may buckle.

  The above-mentioned minute gap G seems to be slight, but when there is no gap, the optical fiber core wire is in a state in which the laying tube is held by a protective coating from the surroundings, that is, in a state where the tip of the laying tube is reinforced and not bent However, if there is a gap, the optical fiber core may move freely within the gap, and the tip of the laying tube may be detached from the optical fiber core and cannot be directly attacked.

  Further, the radius of the bottom arc of the V-shaped groove 14 is 0.2 mm, the inclination angle θ is 60 degrees, the depth is 0.3 mm, and a known halogen-based, non-halogen-based, or phosphorus-based flame retardant is used for the protective coating. A low-friction / flame retardant polyurethane composition blended in an appropriate amount is employed, and its hardness is 90 (HDA) or more, and the friction coefficient against vinyl chloride is 0.2 or less.

  FIG. 1B shows a second embodiment, 11 is a two-core optical fiber in which two optical fiber cores having an outer diameter of 0.25 mm are arranged in parallel, and 12 is spaced from both sides of the optical fiber. A tension member of a 0.45 mmφ aramid fiber reinforced plastic string arranged, 13 is a galvanized steel wire (support wire) of 1.2 mmφ, on which an outer diameter of 3.0 mmφ is formed by a low friction / flame retardant polyurethane composition. An outer jacket 16 having an outer diameter of 2.0 mmφ is provided via the protective coating 15 and the bridge 17.

  This embodiment is basically the same as embodiment 1 except that a support line and a jacket are provided. The only difference is that the inclination angle α of the V-shaped groove is only 30 degrees. Omitted.

  FIG. 1C shows a third embodiment, 11 is a two-core optical fiber in which two optical fiber cores having an outer diameter of 0.25 mm are arranged in parallel, and 12 is spaced from both sides of the optical fiber. Arranged 0.45mmφ aramid fiber reinforced plastic cord tension member, 13 is a 1.2mmφ galvanized steel wire (support wire), 2.4mm short axis made of low friction and flame retardant polyurethane composition X An oval protective coating 15 having a major axis of 2.7 mm and a jacket having an outer diameter of 2.4 mm are provided via a bridge 17.

  This embodiment is basically the same as the second embodiment except that the protective coating is oval and the inclination angle θ of the V-shaped groove is 60 degrees. The description will be omitted.

  FIG. 1D shows a fourth embodiment, 11 is a four-core optical fiber ribbon in which four optical fiber cores having an outer diameter of 0.25 mm are arranged in parallel, and 12 is an interval on both sides of the optical fiber ribbon. A tension member of a 0.45 mmφ aramid fiber reinforced plastic string, which is opened and arranged, 13 is a 1.2 mmφ galvanized steel wire (support wire) on which a short axis 2 is formed by a low friction / flame retardant polyurethane composition. An oval protective coating 15 of 0.0 mm × long axis 4.0 mm and a jacket 16 having an outer diameter of 2.0 mmφ are provided via a bridge 17.

  The protective coating 15 is formed by a pipe extrusion method, and a small gap G of 0.11 mm on the short axis side and 0.35 mm on the long axis side is formed between the optical fiber tape core wire 11 and the protective coating 15. In the surface length direction of the protective coating 15, a V-shaped concave groove 14 having a round bottom in the shape of an arc and a minute round R formed at a portion where the valley surface and the outer peripheral surface intersect is provided. Here, the minute gap G can be widened to 0.5 mm on both the short axis side and the long axis side, but it is not preferable to widen the gap for the same reason as in the first embodiment. Since the configuration other than the above is basically the same as the first embodiment and the second embodiment, the description thereof will be omitted.

フィールド試験場所
Ａ：株式会社きんでん殿
１：京都支店管内、２：和歌山支店管内、３：奈良支店管内、４：神戸支店管内、
５：姫路支店管内、６：中央区支店管内、７：社員宅：滋賀県
Ｂ：タツタ電線株式会社大阪工場
Ｃ： 同 福知山工場
樹種 Ａ：樫、 Ｂ：欅、 Ｃ：椚、 Ｄ：柿、 Ｅ：桜、 Ｆ：メタセコイヤ、
Ｇ：プラタナス、 Ｈ：椋、 Ｉ：合歓

Field test place A: Kinden Inc. 1: Kyoto branch jurisdiction 2: Wakayama branch jurisdiction 3: Nara branch jurisdiction 4: Kobe branch jurisdiction
5: Himeji branch jurisdiction, 6: Chuo-ku branch jurisdiction, 7: Employee residence: Shiga Prefecture B: Tatsuta Electric Cable Co., Ltd. Osaka factory C: Fukuchiyama factory E: Sakura, F: Metasequoia
G: plane tree, H: 椋, I: Neh

Verification test

  Next, in order to confirm the antifungal effect of the present invention, each sample of the conventional example shown in Example 1, Example 2, Example 3 and FIG. 4 was placed on the trunk surfaces of various trees of the test site shown in Table 1. After laying and observing the state of insertion of the laying tube after two months from July 31, 2004, we confirmed that the laying tube of the laying tube was found at 3 test sites and 3 species. All were samples of the conventional example, and no penetration wrinkles were confirmed in the samples of the examples of the present invention.

  As described above, the outer shape of the drop cable body is circular or elliptical, and by specifying the shape and depth of the bottom of the V-shaped groove formed on the surface of the protective coating, it becomes difficult for insects to stop, The insertion becomes difficult, and even if the laying tube is inserted, the possibility that the optical fiber core is damaged or disconnected is reduced by the gap between the optical fiber and the protective coating.

  In the case of the one with a support wire, snow accretion does not grow and the mechanical strength becomes high, and by selecting a protective coating material with a low friction coefficient, it is possible to connect it to an optical fiber core wire for drawing and laying work. It can suppress the load and prevent the transmission characteristics from deteriorating, and can prevent the insect spawning tube from being inserted.

In the sectional view of the drop cable according to the present invention, (a) shows Example 1, (b) shows Example 2, (c) shows Example 3, and (d) shows Example 4. FIG. Sectional view of the drop cable according to the prior art (Part 1) (Part 2) Same (Part 3)

Explanation of symbols

10 Drop cable 11 Optical fiber (tape) core wire 12 Tension member 13 Galvanized steel wire (support wire)
14 V-shaped groove 15 Protective coating 16 Jacket 17 Bridge G Gap

Claims (5)

  An optical fiber core wire (11) is arranged in the center, and tension members (12) are arranged at intervals on both sides, and a protective coating (15) having a circular or oval cross section is applied on both (11, 12). In the optical fiber cable (10), the ratio of the major axis / minor axis of the protective coating (15) is 1-2, and the V-shaped groove (14) is formed in the surface length direction of the protective coating (15). And the depth of the V-shaped groove (14) is set to 1/12 to 1/7 of the minor axis of the protective coating (15), and the radius of the valley arc of the V-shaped groove (14). A protective optical transmission cable characterized by being 1/18 to 1/8 of the short axis of the protective coating (15). An optical fiber core wire (11) is arranged in the center, and tension members (12) are arranged at intervals on both sides, and a protective coating (15) having a circular or oval cross section is applied on both (11, 12). In the optical fiber cable (10), the ratio of the major axis / minor axis of the protective coating (15) is 1-2, and the V-shaped groove (14) is formed in the surface length direction of the protective coating (15). A micro-fiber for forming and preventing the fiber optic core wire (11) from moving freely between the protective coating (15) and the fiber optic core wire (11) to prevent the insect spawning tube from being inserted. Providing a gap (G),
Further, the depth of the V-shaped groove (14) is set to 1/12 to 1/7 of the minor axis of the protective coating (15), and the radius of the valley arc of the V-shaped groove (14) is set to the protective coating. (15) A light-proof optical transmission cable having a short axis of 1/18 to 1/8. An optical fiber core wire (11) is arranged in the center, and tension members (12) are arranged at intervals on both sides, and a protective coating (15) having a circular or oval cross section is applied on both (11, 12). In the optical fiber cable (10), the ratio of the major axis / minor axis of the protective coating (15) is 1-2, and the V-shaped groove (14) is formed in the surface length direction of the protective coating (15). A micro-fiber for forming and preventing the fiber optic core wire (11) from moving freely between the protective coating (15) and the fiber optic core wire (11) to prevent the insect spawning tube from being inserted. Providing a gap (G),
Further, at the midpoint of the line connecting the optical fiber core wire (11) and the tension member (12), the surface of the protective coating (15) on the orthogonal line has an arc bottom and a valley surface and an outer peripheral surface. A fender-proof optical transmission cable characterized in that the V-shaped groove (14) in which minute rounds (R) are formed at the intersecting portion is provided. A support line (13) is disposed on the extension line of the line connecting the optical fiber core wire (11) and the tension member (12) and outside the protective coating (15), and the support line (13) 4. The protective optical transmission cable according to claim 3 , wherein a jacket (16) is provided on the top together with the protective coating (15) via a bridge (17). The protective coating (15), hardness 90 (HDA) or more, of claims 1 to 4, characterized in that the coefficient of friction against polyvinyl chloride was formed with 0.2 or lower friction and flame retardant polyurethane composition The protective optical transmission cable according to any one of the above.

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