JP2006106373A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable that can surely avoid damages to coated optical fibers due to the stabling of ovipositor of cicadas, that has a means of enabling coated optical fibers to be removed, and that can be introduced inside a closure in a hermetically sealed state. <P>SOLUTION: The optical fiber cable is structured, in such a manner that one or more coated optical fibers 11 are arranged in the center of a cable, with a tension member 12 disposed on either side and integrally covered with a jacket 13. On both sides where no tension member 12 is arranged, there is formed a blocked cavity passage 15, in such a manner as to hold the coated optical fibers 11 in-between. Also, where the cross-sectional shape of the cable jacket 13 is designed to be rectangular, the width size L2 of a side face parallel to the line Y connecting the tension members 12 is made ≤3.5 mm and the width size L1 on the end face orthogonal to the line is made ≤2.5 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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, there is known a configuration in which a hollow portion in which a cross-sectional shape of a notch is substantially closed on the outer jacket surface is formed. This is because, as shown in FIG. 3 (B), a slit in which the notch inlet 6a on the jacket surface side is substantially closed on both sides of the cable jacket 3 where the tension member 2 of the optical fiber core wire 1 is not arranged. The notch 6 having a cavity with a sharp shape on the optical fiber side is formed.

According to this optical fiber cable, since the notch inlet 6a is substantially closed, the wrinkle does not notice the notch, and thus it is difficult to lay eggs, and disconnection of the optical fiber by the laying tube can be prevented. And it is supposed that the notch 6 can be torn like before and an internal optical fiber core wire can be taken out. Further, for example, as shown in FIG. 3C, a method using a shape having no notch on the side surface of the cable jacket 3 is also conceivable.
JP 2002-90594 A

However, as shown in FIG. 3B, even if the notch inlet 6a on the outer surface side is formed with a slit that closes, it is only expected that the wrinkle does not notice the presence of the notch 6, and is completely It is not a countermeasure. In addition, the notch 6 is liable to accumulate moisture such as rain from the notch inlet 6a and may become a water channel to the closure. For this reason, there is a problem that a sealing measure is required at the cable introduction portion of the closure.
The present invention has been made in view of the above-described circumstances, and it is possible to reliably avoid damage to the optical fiber core due to the laying of the laying tube of the pupa, and a means capable of taking out the optical fiber core. It is an object of the present invention to provide an optical fiber cable that can be introduced into a closure in a sealed state.

  The optical fiber cable according to the present invention is an optical fiber cable in which one or more optical fiber cores are arranged at the center of the cable, tension members are arranged on both sides thereof, and are integrally covered with a jacket. Then, on both sides where the tension member is not arranged, a closed hollow path is formed so as to sandwich the optical fiber core wire. When the cross section of the cable jacket is rectangular, the width L2 of the side surface parallel to the line connecting the tension members is 3.5 mm or less, and the width L1 of the end surface perpendicular to the line is 2.5 mm. The following is preferable. 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, it can take out the optical fiber core wire in a cable, without using a dedicated tool, and can avoid reliably damaging an optical fiber core wire by the spawning tube piercing of a spider. . Further, since there is no opening on the outer surface of the cable, water does not enter and accumulate in the cable. When the cable jacket is rectangular, a mark with good identification can be displayed on the side of the cable, and the cable can be introduced in a sealed state without changing the shape of the existing closure.

  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 and FIG. 1C are cable sectional views, and FIG. 2A to FIG. It is a figure which shows the example of this embodiment. In the figure, 11 is an optical fiber core wire, 11 'is a tape core wire, 12 is a tension member, 13 is a jacket, 13a is a jacket side surface, 14 is a support wire portion, and 15 and 15' are hollow paths.

  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. A hollow path 15 is formed in the outer cover 13 so as not to communicate with the outer cover side surface 13a on both sides where the tension member 12 is not disposed. And it cuts into the part by which the coating thickness was reduced by the hollow path 15 of this both sides, and it is comprised so that it can tear by hand so that a cable may be divided into 2 and can take out the optical fiber core wire 11 inside. ing.

  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 is symmetrical with respect to the line Y passing through the center of the cable connecting the tension members 12 on both sides (upper and lower sides) and sandwiches the optical fiber core wire 11 from both sides. Thus, the cavity paths 15 which are parallel and continuous with each other are formed. The cavity 15 is preferably formed on a line X orthogonal to the line Y and passing on the optical fiber core 11, but is point-symmetric about the optical fiber core 11 on both sides of the line Y. It only has to be formed.

  As described with reference to FIG. 1A, the hollow passage 15 is formed by a continuous passage of a cavity that is closed so as not to communicate with the outer jacket side surface 13a. By forming the hollow passage 15, the outer shape of the outer jacket 13 is formed. Will not be affected. In addition, the hollow path 15 may be formed with a circular cross-section that is relatively easy to manufacture as shown in FIG. 1B. For example, as shown in FIG. You may form by the hollow path 15 'of a cross section. In the case of the hollow channel 15 ′ having a triangular cross section, by forming one apex angle so as to face the center of the optical fiber core wire 11, it is possible to resemble a conventional V-shaped notch and to improve the tearability. Can do. In addition, the cross-sectional shape of the hollow passages 15 and 15 ′ is not particularly limited as long as the hollow passages 15 and 15 ′ are formed in a form that does not contact the jacket side surface 13 a and the optical fiber core wire 11.

  By constructing the optical fiber cable as described above, there is no entrance on the surface of the jacket 13 that becomes an insertion port of the egg-laying tube such as a notch or a slit. No piercing. As a result, the optical fiber core wire 11 can be avoided from being damaged by the laying tube. Then, by performing an operation of cutting and tearing the outer cover with a nipper, which is defined as a standard, to a portion where the thickness is reduced by the cavity 15, the light having a conventional notch Similarly to the fiber cable, the optical fiber core wire 11 in the cable can be taken out.

  Further, in the above-described optical fiber cable, since the hollow path 15 does not communicate with the outside except at both ends of the cable, moisture or the like does not enter into the hollow path 15 or become a water path. . Further, when the drop optical fiber cable is pulled down from an outdoor closure, since there is no recess like a groove on the cable surface, it can be introduced in a sealed or airtight state with respect to the introduction portion of the closure. In addition, when the cross-sectional shape of the jacket 13 of the optical fiber cable is rectangular, the surface portion is flat and there are no openings or slits. Therefore, as shown in FIG. Easy to handle and can be applied neatly.

  In the optical fiber cable having the above-described configuration, for example, one or several standard coated outer diameters of 0.25 mm are used for the optical fiber core 11 housed in the cable, and the tension member 12 is steel having an outer diameter of about 0.4 mm. It is assumed that a steel wire having an outer diameter of 1.2 mm is used as the wire of the support wire portion 14 using a wire, glass fiber reinforced plastic (FRP), or aramid fiber reinforced (K-FRP).

  In this case, if the jacket 13 that is the main body of the optical fiber cable is rectangular, the width L2 of the side surface 13a parallel to the line Y connecting the upper and lower tension members 12 is 3.5 mm or less, and is orthogonal thereto. The width L1 of the end face is preferably 2.5 mm or less. Further, the height dimension L3 including the support wire portion 14 is set to 5.5 mm or less. In this case, the hollow path 15 can be formed with a diameter of about 0.8 mm. 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.

  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, it is symmetrical with respect to the line Y passing through the center of the cable connecting the upper and lower tension members 12, or symmetrical with respect to the central optical fiber core, and parallel to each other so as to sandwich the optical fiber core 11 from both sides. A continuous cavity 15 is formed.

FIG. 2B is a diagram showing an example in which the cross-sectional shape of the jacket 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, it is symmetrical with respect to the line Y passing through the center of the cable connecting the upper and lower tension members 12, or symmetrical with respect to the central optical fiber core, and parallel to each other so as to sandwich the optical fiber core 11 from both sides. A continuous cavity 15 is formed.
2 (A) and 2 (B), only the outer shape of the jacket 13 is different from that in the example of FIG. Therefore, the tearability of the cable can be ensured as usual.

  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 a single tape core 11 ′ is used. Also in this example, the optical fiber core is symmetric with respect to the line Y passing through the center of the cable connecting the upper and lower tension members 12 or the center. The cavity paths 15 are formed so as to be point-symmetric with respect to each other and parallel to each other so as to sandwich the optical fiber core wire 11 from both sides.

  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. Also in this example, as in FIG. 2C, the optical fiber core wire 11 is symmetrical with respect to the line Y passing through the center of the cable connecting the upper and lower tension members 12 or point-symmetric with respect to the central optical fiber core wire. The cavity paths 15 are formed in parallel with each other so as to sandwich them from both sides. However, when the two tape cores 11 ′ are overlapped, the thickness in the stacking direction needs to be slightly increased in order to secure the hollow path 15.

  As shown in FIG. 2 (C) or FIG. 2 (D), by using the tape core wire 11 ′, it is easier to increase the number of cores than bundling a plurality of optical fiber core wires as shown in FIG. 2 (B). Can be realized. Further, the optical fiber core wire can be prevented from being damaged by piercing the spawning tube of the pupa, and the tearability of the cable can be ensured in the same manner as described in FIG.

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 casing, 13a ... Outer casing side surface, 14 ... Support line part, 15, 15' ... Hollow path.

Claims (4)

An optical fiber cable in which one or more optical fiber cores are arranged in the center of the cable, tension members are arranged on both sides thereof, and are integrally covered with a jacket,
An optical fiber cable characterized in that a hollow path closed so as to sandwich the optical fiber core wire is formed on both sides where the tension member is not arranged.   The optical fiber cable according to claim 1, wherein a cross-sectional shape of the jacket is a rectangular shape.   The width dimension L2 of the side surface parallel to the line connecting the tension members is 3.5 mm or less, and the width dimension L1 of the end surface orthogonal to the line is 2.5 mm or less. Fiber optic cable.   The optical fiber cable according to claim 1, wherein the optical fiber core is a multi-fiber optical fiber ribbon.

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