JP3956960B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to an optical fiber cable in which tension members are arranged on both sides of an optical fiber core disposed in the center of the cable and are integrally covered with a jacket and used as a drop optical fiber cable or an indoor optical fiber cable.

  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. For this reason, the demand of the drop optical fiber cable used for drawing in to a house and the indoor optical fiber cable for indoor wiring is increasing.

  In these optical fiber cables, for example, as shown in FIG. 3A, generally, tension members 2 are arranged in parallel on both sides of the optical fiber core wire 1, and are covered with a cable jacket 3 so as to be integrally covered. A structure with increased tensile strength is used. Further, this optical fiber cable is integrally provided with a support wire portion 4, and the support wire portion 4 is removed by tearing by hand so that it can also be used as an indoor optical fiber cable. In addition, V-shaped notches 5 for tearing the cable jacket 3 by hand and taking out the optical fiber core wire 1 are usually provided on both side surfaces of the cable jacket 3.

  Along with the increased use of optical fiber cables of this structure, problems that did not exist in the past have also occurred. For example, there is an example in which the spear pierces the egg-laying tube into the jacket 3 of the optical fiber cable from the portion of the notch 5 and damages the optical fiber core wire 1 inside. In particular, the damage caused by bear moths, which are common in western Japan, has occurred, and it is estimated that the optical fiber cable was recognized as an object that cocoons lay easily.

On the other hand, some optical fiber cables provided with measures against wrinkles have been proposed. For example, as disclosed in Patent Document 1 and Patent Document 2, a configuration in which the position of the notch tip is displaced from the position of the optical fiber core wire is known. This is because, as shown in FIG. 3B, on the line Y connecting the center of the optical fiber core 1 and the center of the tension member 2, the gap between the perpendicular line dropped from the tip of the notch 5 and the optical fiber core 1. Have a certain distance a. That is, the optical fiber core wire 1 is not present on the extension of the tip of the notch 5, so that the optical fiber core wire 1 is not directly hit by the spawning tube of the spider. Further, for example, as shown in FIG. 3C, a method using a cable jacket 3 having a shape not having a notch is also conceivable.
JP 2002-90593 A JP 2002-328276 A

  However, as shown in FIG. 3B, when the position of the notch 5 is shifted, as described in Patent Document 2, an oblique notch that passes through the notch 5 on both sides and the optical fiber core wire 1 is provided. If it is not torn, the optical fiber core wire 1 may not be exposed due to tearing from the notch tip in the direction perpendicular to the line Y. That is, in order to take out the optical fiber core 1, it is necessary to devise such as making an oblique cut after passing through the optical fiber core 1 with a tool such as a nipper, and a certain skill is required. In addition, in the case where a plurality of optical fiber cores arranged in a line is stored, in order to shift the position of the notch from the optical fiber core by a predetermined distance, it is necessary to increase the cable size. The effect of taking out the optical fiber from the notch cannot be expected.

  The present invention has been made in view of the above-described circumstances, and can prevent the optical fiber core from being damaged by the laying of the spawning tube of the pupa, and securely connect the optical fiber core without requiring skills. An object of the present invention is to provide an optical fiber cable having a wedge-shaped notch that can be exposed and taken out.

The optical fiber cable according to the present invention is an optical fiber cable in which an optical fiber core wire is disposed at the center of the cable, tension members are disposed on both sides thereof, and are integrally covered with a jacket. The outer cover has a rectangular cross-sectional shape, the width dimension L2 of the side surface parallel to the line Y connecting the tension members is 3.5 mm or less, and the width dimension L1 of the end face perpendicular to the line Y is 2.5 mm or less. The wedge-shaped notch is formed by cutting from a rectangular corner of the jacket. The wedge-shaped notch opening center wedge notches, the line Y with respect located on the inclined line X that passes through the tension member having an angle of 15 ° to 45 °, between the notch tip and the optical fiber of the wedge Is smaller than the distance between the tip of the notch and the tension member on the inclined line X, and is formed to be point symmetric with respect to the center of the cable .

Further, it is preferred that the opening angle of the wedge-shaped notch to be formed at 30 ° or less, further, it is preferable that the distance D of the slope line direction between the notch tip of the wedge-shaped notch is formed at 1.0mm or less. In addition, this invention is applicable also when the optical fiber core wire is a multi-fiber optical fiber tape core wire.

  ADVANTAGE OF THE INVENTION According to this invention, the optical fiber core wire in a cable can be taken out reliably without using an exclusive tool, and it can avoid that an optical fiber core wire is damaged by the spawning tube piercing of a spider. . When the cable jacket is rectangular, the wedge-shaped notch can be formed from the rectangular corner, so the side of the cable can be widened to display marks with good identification, and without changing the shape of the existing closure The cable can be introduced in a sealed state.

  An embodiment of the present invention will be described with reference to the drawings. 1A is a perspective view for explaining the outline of an optical fiber cable according to the present invention, FIG. 1B is a cross-sectional view of the cable, and FIGS. 2A to 2D are examples of other embodiments. FIG. In the figure, 11 is an optical fiber core, 11 'is a tape core, 12 is a tension member, 13 is a jacket, 13a is a jacket side, 14 is a support line, 15 is a wedge-shaped notch, and 15a is a notch tip. .

  For example, as shown in FIG. 1A, an optical fiber cable according to the present invention includes one or more optical fiber core wires 11 at the center of the cable, and tension members 12 on both sides (upper and lower sides in the figure). It is intended to have a configuration in which it is arranged and covered integrally with the outer cover 13. The jacket 13 is formed with a wedge-shaped notch 15 that is point-symmetric with respect to the center of the cable. By manually tearing the cable in half from the wedge-shaped notches 15 on both sides, the inner optical fiber core 11 is exposed and can be taken out.

  The optical fiber core wire 11 in the present invention is referred to as an optical fiber strand in which a glass fiber having a standard outer diameter of 125 μm is coated with a coating outer diameter of about 250 μm, and a reinforcing coating is further applied to the outside thereof. All of the configurations described above shall be included. This optical fiber core wire 11 is arranged by directly covering one to several wires with a jacket 13. As shown in FIGS. 2C and 2D described later, a plurality of optical fibers 11 are arranged. It is also possible to arrange the fiber core wires in the form of a tape core wire integrated with a common coating.

  In the description of the present invention, a self-supporting optical fiber cable in which a support wire portion 14 is integrally provided on the main body portion of the optical fiber cable is used. However, the present invention can be similarly applied to use in a form in which the support line portion 14 is removed, or to an optical fiber cable that does not have the support line portion 14 from the beginning. In addition, the jacket 13 constituting the main body of the optical fiber cable is often rectangular in cross section, but is not particularly limited to this, and is shown in FIGS. 2A and 2B described later. As described above, it may be oval or circular.

As shown in FIG. 1B, the optical fiber cable according to the present invention has a predetermined angle θ with respect to a line Y passing through the center of the cable connecting the tension members 12 on both sides, and passes through the tension member 12. On the inclined line X, a wedge-shaped notch 15 for taking out the optical fiber core wire 11 is formed. The wedge-shaped notch 15 is cut from a rectangular corner portion of the jacket 13, the opening center of the notch is on the inclined line X, is formed point-symmetrically with respect to the center of the cable body portion, and has at least a pair of notches. Just do it. In FIG. 1B, it is provided in the upper right and lower left portions, but may be provided in the upper left and lower right portions. The angle θ of the inclined line X with respect to the line Y is preferably 15 ° to 45 °. In addition, the wedge-shaped notch 15 is preferably formed at an opening angle β of 30 ° or less as compared with a conventional V-shaped notch.

Wedge notch 15, by opening the center of the notch is formed such that on the inclined line X, the tension member 12 is to be located on an extension line of the sharp notch tip 15a. As a result, it is possible to optical fibers 11 on the notch tip 15a of the extension line (the inclined line X) is to be absent. If the angle θ of the inclined line X is less than 15 °, the inclined line X may approach the optical fiber core wire 11 and come into contact with the spawning tube of the cocoon. If the angle θ exceeds 45 °, the jacket It becomes difficult to reliably expose the optical fiber core wire 11 when the wire 13 is torn. Further, by setting the opening angle β of the wedge-shaped notch 15 to a small angle of 30 ° or less, the piercing direction of the spawning tube can be directed to the extending direction of the notch tip 15a.

  By configuring the optical fiber cable as described above, even if the spider inserts the spawning tube from the wedge-shaped notch 15 and pierces the cable, the spawning tube is pierced toward the tension member 12. The optical fiber core wire 11 can avoid receiving a direct hit by the laying tube. Further, the distance from the entrance of the wedge-shaped notch 15 to the optical fiber core 11 is larger than the notch formed in the vertical direction from the outer side surface as in the conventional FIG. As a result, it is possible to effectively avoid the optical fiber core wire 11 from being damaged by the direct hit by the spawning tube. Further, when the wedge-shaped notch 15 is torn by hand, a breakage occurs so as to pass between the notch tip 15a whose coating thickness is thin and the central optical fiber core 11, thereby exposing the optical fiber core 11. be able to.

As shown in FIG. 1B, when the cross-sectional shape of the jacket 13 of the optical fiber cable is rectangular, the wedge-shaped notch 15 is formed by cutting from the corner of the jacket 13 toward the tension member 12. Preferably it is done. Thereby, as is apparent from the drawing, the distance between the wedge-shaped notch tip and the optical fiber core wire is smaller than the distance between the notch tip and the tension member on the inclined line X. As a result, breakage is likely to occur between the notch tip having a small distance and the optical fiber core wire, and the optical fiber core wire can be easily exposed. Further, by forming the wedge-shaped notches 15 from the corners of the outer cover 13, the effective width of both side surfaces 13a of the outer cover 13 can be widened. As shown in FIG. It is easy to identify and can be applied neatly. Further, when the optical fiber cable of this shape is dropped as an optical fiber cable from an outdoor closure, it can be introduced in a sealed state without any additional changes to the introduction part of the existing closure.

  Further, for example, one or several optical fiber core wires 11 accommodated in a cable having a standard outer diameter of 0.25 mm are used, and the tension member 12 is a steel wire or glass fiber reinforced plastic having an outer diameter of about 0.4 mm. (FRP), aramid fiber reinforced plastic (K-FRP) or the like is used, and a steel wire having an outer diameter of 1.2 mm is used as the wire of the support wire portion 14. In this case, if the jacket 13 that is the main body of the optical fiber cable is rectangular, the width dimension L2 of the side surface 13a parallel to the line Y passing through the cable center connecting the upper and lower tension members 12 is 3.5 mm or less. It is preferable that the width dimension L1 of the end surface orthogonal to this is 2.5 mm or less. Further, the height dimension L3 including the support wire portion 14 is set to 5.5 mm or less. With this size and shape, it can be handled in the same way as an existing drop optical fiber cable, and existing closures and peripheral parts can be used as they are.

  In the optical fiber cable having the rectangular shape described above, the distance D in the inclined line X direction between the notch tips 15a between the wedge-shaped notches 15 formed symmetrically is preferably 1.0 mm or less. By setting the distance D to 1.0 mm or less, the inner optical fiber core 11 can be surely exposed when the wedge-shaped notches 15 on both sides are torn open, and the optical fiber core 11 can be exposed. Removal can be facilitated. In addition, even if the distance D is substantially zero, it is possible to avoid a direct hit by the spawning tube of the pupa.

  FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 2 (A) is a diagram showing an example in which the cross-sectional shape of the jacket 13 of the cable main body is made elliptical. In this example, a tension member 12 is disposed on both sides of one optical fiber core wire 11. Also in this example, the optical fiber core has an angle θ (15 ° to 45 °) with respect to the line Y passing through the center of the cable connecting the tension members 12 on both sides, and on the inclined line X passing through the tension member 12. A wedge-shaped notch 15 for taking out the line 11 is formed. The wedge-shaped notch 15 may have an opening angle β of 30 ° or less as described with reference to FIG. 1 (B). The wedge-shaped notch 15 is formed on the inclined line X from the outer surface of the elliptical envelope, thereby forming an acute notch tip. The tension member 12 is positioned on the extension of 15a. As a result, it is possible to prevent the optical fiber core wire 11 from existing on the extension of the notch tip 15a.

  FIG. 2B is a diagram illustrating an example in which the cross-sectional shape of the outer cover 13 of the cable main body is circular. In this example, four optical fiber cores 11 are bundled and tension members 12 are arranged on both sides thereof. Also in this example, the optical fiber core has an angle θ (15 ° to 45 °) with respect to the line Y passing through the center of the cable connecting the tension members 12 on both sides and on the inclined line X passing between the tension members 12. A wedge-shaped notch 15 for taking out the line 11 is formed. The wedge-shaped notch 15 may have an opening angle β of 30 ° or less as described with reference to FIG. 1B. By forming the wedge-shaped notch 15 on the inclined line X from the side surface of the circular envelope, the sharp notch tip is formed. The tension member 12 is positioned on the extension of 15a. As a result, it is possible to prevent the optical fiber core wire 11 from existing on the extension of the notch tip 15a.

  2 (C) and 2 (D) show a tape shape in which a plurality of optical fibers are arranged in a line instead of bundling the plurality of optical fibers 11 in FIG. This is an example using the tape core wire 11 '. FIG. 2C shows a case where one tape core wire 11 ′ is used. Also in this example, the angle θ (15 ° to 45 °) with respect to the line Y passing through the center of the cable connecting the tension members 12 on both sides. And a wedge-shaped notch 15 for taking out the tape core wire 11 ′ is formed on the inclined line X passing through the tension member 12. The wedge-shaped notch 15 may have an opening angle β of 30 ° or less in the same manner as described with reference to FIG. 1 (B), and is formed on the inclined line X from a rectangular corner, thereby forming a sharp notch tip. The tension member 12 is positioned on the extension of 15a. As a result, it is possible to prevent the tape core wire 11 'from existing on the extension of the notch tip 15a.

  FIG. 2D shows an example in which two tape core wires 11 ′ are used in a shape that does not have the support wire portion 14. In this example as well, on the inclined line X having an angle θ (15 ° to 45 °) with respect to the line Y connecting the tension members 12 on both sides as in FIG. 2C and passing through the tension member 12. A wedge-shaped notch 15 for taking out the tape core wire 11 'can be formed. However, since the inclined line X may approach the tape core 11 'when the two tape cores 11' are overlapped, the angle θ is made larger than in the case of FIG. In this case, the wedge-shaped notch 15 is formed on the inclined line X from the rectangular side surface 13a, but the tension member 12 is positioned on the extension of the sharp notch tip 15a. As a result, it is possible to prevent the tape core wire 11 'from existing on the extension of the notch tip 15a.

It is a figure explaining the outline and embodiment of the present invention. It is a figure explaining other embodiment of this invention. It is a figure explaining the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Optical fiber core wire, 11 '... Tape core wire, 12 ... Tension member, 13 ... Outer sheath, 13a ... Outer side surface, 14 ... Support wire part, 15 ... Wedge-shaped notch, 15a ... Notch tip.

Claims (4)

An optical fiber cable in which an optical fiber core wire is arranged at the center of the cable and tension members are arranged on both sides of the optical fiber cable and are integrally covered with a jacket,
The outer cover has a rectangular cross-sectional shape, a width L2 of a side surface parallel to the line Y connecting the tension members is 3.5 mm or less, and a width L1 of an end surface orthogonal to the line Y is 2.5 mm. in the following, wedge-shaped notch, inclined line passing through the tension member opening center of the wedge-shaped notches are cut from the envelope of the rectangular corner portion, prior to Kira in Y with an angle of 15 ° to 45 ° located on X, the distance between the wedge-shaped notch distal end and the optical fiber is smaller than the distance between the tension member in said notch tip and the tilt on the line X, a point symmetric about the center cable optical fiber cables, characterized in that it is formed as.   The optical fiber cable according to claim 1, wherein an opening angle of the wedge-shaped notch is 30 ° or less. The optical fiber cable according to claim 1 or 2, wherein a distance D in the inclined line direction between the notch tips is 1.0 mm or less . A fiber optic cable according to claim 1 or 2, characterized in that said optical fiber is an optical fiber ribbon of the multi-core.

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