Fiber optic cable

Abstract

The purpose of the present disclosure is to provide an optical fiber cable in which, when an outer cover thereof having three or more tensile-strength bodies is cut out by a cutter or the like, a tearing string becomes exposed earlier than any of the tensile-strength bodies.　In order to achieve the purpose, an optical fiber cable (1) according to the present disclosure comprises: an optical fiber core wire (14); an outer cover (11) that covers the optical fiber core wire (14); three or more tensile-strength bodies (12) that are arranged along the long axis of the optical fiber core wire (14) inside the outer cover (11); and a tearing string (13) in which a portion of the outer circumference is located outside an outer tangent (17) of the outer circumference of the three or more tensile-strength bodies (12) in a cross-section of a portion perpendicular to the long axis direction of the outer cover (11), and a portion of the outer circumference is in contact with inner circumference of the outer cover (11) or is located inside the inner circumference of the outer cover (11) in a cross-section perpendicular to the long axis direction of the outer cover (11).

Description

[Technical field]

[0001] The present disclosure relates to an optical fiber cable having a rip string that is installed inside the optical fiber cable and used for rip-cutting. [Background technology]

[0002] Currently, optical fibers are used in communication networks for providing multimedia services. Specifically, optical fiber cables are used, which are made of bundled optical fiber cores covered with a sheath. Conventionally, optical fiber cables have a groove-type slot rod, and the optical fiber cores are housed in the groove, but non-slot type optical fiber cables that do not use slot rods are now being used to reduce the diameter (see, for example, Patent Document 1).

[0003] FIG. 1 is a cross section of a non-slotted optical fiber cable 1, in which 11 is the outer sheath, 12 is a tensile member, 13 is a string for slicing the outer sheath (hereinafter, the "string for slicing the outer sheath" will be abbreviated to "slicing string"), and 14 is an optical fiber core.

[0004] A tension member 12 is embedded in the jacket 11 parallel to the longitudinal direction of the optical fiber cable 1. The tension member 12 protects the optical fiber core 14 from tension in the longitudinal direction acting on the optical fiber cable 1, and is made of a material such as a steel wire or fiber-reinforced plastic, and has a thickness that allows it to exhibit sufficient rigidity. The tension member 12 may consist of multiple pieces (see, for example, Patent Document 2).

[0005] A ripping string 13 is also embedded in the jacket 11 to easily cut the jacket and take out the optical fiber core 14 inside the optical fiber cable, and the ripping string 13 can be exposed and taken out by scraping off the jacket with a blade or the like. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4619424 (NTT) [Patent Document 2] JP 2015-166806 A (NTT) Summary of the Invention [Problem to be solved by the invention]

[0007] The tension members 12 are essential for protecting the optical fiber cable 1 and the optical fiber core 14. However, the tension members 12 prevent the cable diameter from being reduced due to their thickness, and when the tension members 12 are arranged in an asymmetrical position on the optical fiber cable 1, they can cause bending directionality, reducing the ease of handling of the optical fiber cable. In response to this, as shown in Patent Document 2, by arranging multiple tension members in symmetrical positions, it is possible to reduce the diameter of each tension member and alleviate the bending directionality.

[0008] On the other hand, in the case of having a plurality of tensile members 12 as in Patent Document 2, when the jacket 11 is scraped off using a blade or the like, it comes into contact with the tensile members 12 before reaching the ripping cord 13, making it difficult to remove the ripping cord 13. In this case, the ripping cord 13 cannot be used to slit the jacket 11, and it is necessary to directly insert a sharp tool into the housing portion of the optical fiber 14 to slit it, which may damage the optical fiber 14 and takes a long time to slit.

[0009] In order to solve the above-mentioned problems, the present disclosure aims to provide an optical fiber cable in which, when an outer jacket having three or more tensile members is scraped away with a blade or the like, a rip cord is exposed before the tensile members. [Means for solving the problem]

[0010] In order to achieve the above object, the optical fiber cable of the present disclosure has a rip cord disposed inside the jacket and outside the tensile members in the longitudinal direction.

[0011] Specifically, the optical fiber cable according to the present disclosure comprises: An optical fiber core; a jacket that covers the optical fiber; Three or more tension members are arranged inside the jacket along a longitudinal axis of the optical fiber core; a rip cord, the outer periphery of which is partly outside the outer tangent to the outer periphery of the three or more tensile members in a cross section perpendicular to the longitudinal direction of the outer sheath, and the outer periphery of which is partly in contact with the inner periphery of the outer sheath or partly inside the inner periphery of the outer sheath in a cross section perpendicular to the longitudinal direction of the outer sheath; Equipped with.

[0012] For example, the optical fiber cable according to the present disclosure may include: The three or more tension members have outer tangents located outside the inner circumference of the outer covering.

[0013] For example, the optical fiber cable according to the present disclosure may include: The rip cord is made up of a plurality of cords.

[0014] For example, the optical fiber cable according to the present disclosure may include: The rip cord has a structure in which the multiple cords are twisted together.

[0015] For example, the optical fiber cable according to the present disclosure may include: The rip cord has a structure in which the multiple cords are interwoven with each other.

[0016] For example, the optical fiber cable according to the present disclosure may include: The rip cord is formed by bonding the plurality of cords together.

[0017] For example, the optical fiber cable according to the present disclosure may include: At least one of the rip cords is arranged in a straight line, and at least one of the cords is arranged in a wavy pattern that repeatedly contacts and separates from the cord arranged in the straight line (hereinafter abbreviated as "straight-line cord"). The portion of the cord arranged in the wavy pattern that contacts the straight-line cord is bonded or welded and is located inside the outer tangent, and the portion that separates from the straight-line cord is located outside the outer tangent.

[0018] For example, the optical fiber cable according to the present disclosure may include: The outer cover has a thickness smaller at a portion where the rip cord is provided than at a portion where the rip cord is not provided.

[0019] The above-mentioned inventions can be combined as much as possible. Effect of the Invention

[0020] According to the present disclosure, it is possible to provide an optical fiber cable in which, when an outer jacket having three or more strength members is scraped away with a blade or the like, a rip cord is exposed before the strength members. [Brief description of the drawings]

[0021] [Figure 1] 1 is an example of a cross section of a non-slotted optical fiber cable. [Diagram 2] 1 is an example of a cross section of a non-slotted optical fiber cable according to the present invention. [Diagram 3] 3 is an example of a cross section near a rip string of an optical fiber cable according to the present invention. [Figure 4] 3 is an example of a cross section near a rip string of an optical fiber cable according to the present invention. [Diagram 5] 3 is an example of a cross section near a rip string of an optical fiber cable according to the present invention. [Figure 6] 2 is an example of a cross section in the longitudinal direction of an optical fiber cable according to the present invention. [Figure 7] 1 is an example of a cross section of an optical fiber cable according to the present invention. [Figure 8]1 is an example of a cross section of an optical fiber cable according to the present invention. [Figure 9] 1 is an example of a cross section of an optical fiber cable according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are assumed to indicate the same components.

[0023] (Embodiment) An example of a cross section perpendicular to the longitudinal direction of an optical fiber cable according to an embodiment of the present invention is shown in Fig. 2. Reference numeral 1 denotes an optical fiber cable, 11 denotes an outer jacket, 12 denotes a tension member, 13 denotes a rip cord, 14 denotes an optical fiber core, and 17 denotes an outer tangent.

[0024] The optical fiber cable 1 includes an outer jacket 11, a tension member 12, a rip cord 13, and an optical fiber core 14.

[0025] The jacket 11 covers one or more optical fibers 14. The jacket 11 may cover the optical fibers 14 directly, or may cover the optical fibers 14 covered with a sheath together with the sheath.

[0026] The jacket 11 has three or more tension members 12 inside along the longitudinal axis of the optical fiber core 14. The tension members 12 may be made of materials such as steel wires or fiber-reinforced plastic. In this embodiment, the inside of the jacket 11 refers to the region between the inner and outer circumferences of the jacket 11 in the cross section of the optical fiber cable 1 shown in FIG.

[0027] In this embodiment, in a cross section perpendicular to the longitudinal direction of the jacket 11, the outer tangent 17 is the periphery of a rounded polygon formed by connecting the outer peripheries of three or more strength members 12 with the outermost common tangents to the outer peripheries of adjacent strength members 12. In Fig. 2, the outer tangent 17 of a rounded rectangle is shown as an example, but is not limited to this.

[0028] It is desirable that the outer tangent 17 is located outside the inner circumference of the jacket 11 in a cross section perpendicular to the longitudinal direction of the jacket 11. In this way, when the jacket 11 is scraped away with a blade or the like, the tensile members 12 are exposed before the optical fiber 14, so that the optical fiber 14 can be protected.

[0029] A part of the outer periphery of the rip cord 13 is outside the outer tangent 17 in at least some cross sections perpendicular to the longitudinal direction of the outer jacket 11. This is referred to as requirement 1. When a part of the outer periphery of the rip cord 13 is outside the outer tangent 17 in all cross sections perpendicular to the longitudinal direction of the outer jacket 11, the rip cord 13 can be exposed by scraping the outer jacket 11 from the rip cord 13 side with a blade or the like in any cross section of the outer jacket 11. On the other hand, when a part of the outer periphery of the rip cord 13 is outside the outer tangent 17 only in some cross sections perpendicular to the longitudinal direction of the outer jacket 11, in order to expose the rip cord 13, it is necessary to scrape the outer jacket 11 from the rip cord 13 side with a blade or the like in the cross sections where a part of the outer periphery of the rip cord 13 is outside the outer tangent 17.

[0030] Furthermore, in a cross section perpendicular to the longitudinal direction of the outer jacket 11, a part of the outer periphery of the rip cord 13 is in contact with the inner periphery of the front outer jacket 11 or is located inside the inner periphery of the outer jacket 11. This is referred to as requirement 2. It is preferable that a part of the outer periphery of the rip cord 13 is in contact with the inner periphery of the front outer jacket 11 or is located inside the inner periphery of the outer jacket 11 in all cross sections perpendicular to the longitudinal direction of the outer jacket 11. This makes it possible to cut the entire outer jacket 11 cleanly by pulling the rip cord 13, thereby exposing the optical fiber core 14. Furthermore, the rip cord 13 may be located outside the inner periphery of the outer jacket 11 as long as it can cut the entire outer jacket 11 cleanly.

[0031] It is desirable that the rip cord 13 satisfies the above requirement 1 and requirement 2 in at least a part of a cross section perpendicular to the longitudinal direction of the outer jacket 11. For example, the rip cord 13 may satisfy both requirement 1 and requirement 2 by being located between two tensile members 12 as shown in Fig. 2. The rip cord 13 may satisfy requirement 1 and requirement 2 in different cross sections perpendicular to the longitudinal direction of the outer jacket 11. In addition, the rip cord 13 does not necessarily have to be located in two places, and may be located in three or more places.

[0032] A mark may be provided on the surface of the outer jacket 11 to indicate a position where the outer jacket 11 should be cut with a blade or the like. For example, When a portion of the outer periphery of the rip cord 13 is outside the outer tangent 17 only in a cross section perpendicular to the longitudinal direction of the outer jacket 11, the rip cord 13 can be exposed more accurately by providing a mark on the outer periphery of the outer jacket 11 in a cross section on the surface of the outer jacket 11 where a portion of the outer periphery of the rip cord 13 is outside the outer tangent 17.

[0033] The structure of the rip cord 13 of the optical fiber cable 1 will be described with reference to FIGS.

[0034] An example of a cross section of the optical fiber cable 1 near the rip cord 13 is shown in Figures 3 to 5. Figures 3 to 5 show only a portion of the jacket 11 including two strength members 12 and one rip cord 13 located between the two strength members 12 in a cross section perpendicular to the longitudinal direction of the optical fiber cable 1. Reference numeral 15 denotes the outermost common tangent drawn between adjacent strength members 12, and is a part of an outer tangent 17. In the following, in Figures 3 to 5, the outer tangent 17 will be described as the common tangent 15 in order to use the rip cord 13 and two strength members 12 for explanation.

[0035] The rip cord 13 may have any shape. For example, the cross section may be a circle as shown in Fig. 3 or a rectangle as shown in Fig. 4, and the rip cord 13 may be disposed so that in at least a part of the cross section perpendicular to the longitudinal direction of the outer jacket 11, a part of the outer circumference is located outside the common tangent line 15, and another part of the outer circumference is in contact with the inner circumference of the outer jacket 11 or located inside the inner circumference of the outer jacket 11.

[0036] The ripping cord 13 may be composed of multiple cords, as shown in Fig. 5. In this case, the ripping cord 13 may be arranged such that a part of the outer periphery of at least one of the multiple cords constituting the ripping cord 13 is located outside the common tangent line 15, and at least a part of the outer periphery of any of the multiple cords is in contact with the inner periphery of the outer jacket 11 or is located inside the inner periphery of the outer jacket 11.

[0037] The rip cord 13 may have a structure in which a plurality of cords are twisted together. The rip cord 13 may have a structure in which a plurality of cords are woven together. The rip cord 13 may have a structure in which a plurality of cords are bonded together. With these structures, by taking out at least one of the plurality of rip cords 13, the other rip cords 13 can be taken out at the same time.

[0038] FIG. 6 shows an example of a cross section of the optical fiber cable 1 along its longitudinal direction.

[0039] At least one of the rip cords 13a is arranged in a straight line, and at least one of the rip cords 13b is arranged in a wavy line that repeatedly contacts and separates from the straight line-arranged cords 13a (hereinafter, the "straight line-arranged cords 13a" will be abbreviated as "straight line-shaped cords 13a"). The wavy line-arranged cords 13b (hereinafter, the "wavy line-arranged cords 13b" will be abbreviated as "wavy line-shaped cords 13b") have a portion that contacts the straight line-shaped cord 13a bonded or welded and located inside the outer tangent 17, and a portion that separates from the straight line-shaped cord 13a located outside the outer tangent 17. It is desirable that the straight line-shaped cords 13a have a part of their outer circumference that contacts the inner circumference of the outer sheath 11 or located inside the inner circumference of the outer sheath 11 in all cross sections perpendicular to the long axis direction of the outer sheath 11. It is desirable that the amplitude direction of the wavy line-shaped cords 13b is the radial direction of the outer sheath 11.

[0040] The rip string 13 consisting of the straight string 13a and the corrugated string 13b can be formed from two thin strings 13, and since the corrugated string 13b is disposed outside the jacket 11 and is easy to pull out, it is not necessary to thin the jacket thickness at the portion of the jacket 11 where the rip string 13 is disposed, and the strength of the optical fiber cable 1 can be maintained. When the rip string 13 consisting of the straight string 13a and the corrugated string 13b is scraped off the jacket 11 using a blade or the like, it is possible to expose a part of the corrugated string 13b before the tensile body 12, and when the exposed corrugated string 13b is pulled out, the bonded or welded straight string 13a is also pulled out at the same time, so that the jacket 11 is split and the optical fiber 14 can be easily taken out.

[0041] An example of a cross section of the optical fiber cable 1 according to the embodiment of the present invention is shown in FIGS.

[0042] The outer sheath 11 may have a thinner outer sheath thickness at a portion where the rip cord 13 is provided than at a portion where the rip cord 13 is not provided. For example, as shown in FIG. 7, the inner circumference of the outer sheath 11 may be elliptical, and the rip cord 13 may be provided at the tip of the long axis direction of the ellipse. As shown in FIG. 8, a protrusion may be provided at a part of the inner circumference of the circular diameter of the outer sheath 11, and the rip cord 13 may be provided at the tip of the protrusion. As shown in FIG. 9, a protrusion and a flat portion with a low curvature may be provided at the inner circumference of the outer sheath 11, and the rip cord 13 may be provided at the tip of the protrusion. Also, the shape of the outer circumference of the outer sheath 11 may be changed instead of the shape of the inner circumference of the outer sheath 11. Furthermore, both the shape of the inner circumference of the outer sheath 11 and the shape of the outer circumference of the outer sheath 11 may be changed.

[0043] Even if the shape of the inner circumference or the outer circumference of the jacket 11 is changed, the configuration and arrangement of the tension members 12 and the rip cord 13 are the same as those described above.

[0044] By changing the shape of the inner circumference or the outer circumference of the jacket 11, the optical fiber 14 can be easily taken out without changing the shape of the rip string 13.

[0045] According to the optical fiber cable according to the present disclosure, when the jacket 11 is scraped off using a blade or the like, the rip cord 13 can be exposed before the tensile members 12 . [Industrial Applicability]

[0046] The optical fiber cable according to the present disclosure can be applied to the information and communication industry. [Explanation of symbols]

[0047] 1: Fiber optic cable 11:Outer cover 12:Tensile strength body 13: Ripper 14: Optical fiber core 15: Common tangent 16: Adhesive part 17:Outside tangent

Claims

1. An optical fiber core; a jacket that covers the optical fiber; Three or more tension members are arranged inside the jacket along a longitudinal axis of the optical fiber core; a plurality of rip-off strings disposed inside the jacket along a longitudinal axis of the optical fiber; Equipped with The plurality of rip cords include straight cords arranged in a straight line shape, and wavy cords arranged in a wavy shape that repeatedly contacts and separates from the straight cords, A part of an outer periphery of the linear cord is in contact with an inner periphery of the outer cover or is located inside the inner periphery of the outer cover, a portion of the corrugated cord that comes into contact with the straight cord and the straight cord are located inside an outer tangent to an outer periphery of the three or more tension members, a portion of the wavy cord separated from the linear cord is located outside the outer tangent line in a cross section perpendicular to the longitudinal direction of the optical fiber; 1. An optical fiber cable comprising:

2. The wavy cord has a radial direction of the sheath as an amplitude direction of the wavy shape.

2. The optical fiber cable according to claim 1 .

3. The three or more tension members have their outer tangents on the outside of the inner circumference of the outer jacket.

3. The optical fiber cable according to claim 1 or 2.

4. The outer cover has a thickness smaller in a portion where the rip cord is provided than in a portion where the rip cord is not provided.

4. The optical fiber cable according to claim 1, wherein the optical fiber cable is a conductor.

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