JP7444833B2 - How to disassemble optical fiber cable and optical fiber cable - Google Patents

Description

The present invention relates to an optical fiber cable disassembly method and an optical fiber cable.

Conventionally, optical fiber cables as shown in Patent Document 1 below have been known. This optical fiber cable includes a cable main body having an optical fiber, a rip cord, a reinforcing sheet, and an outer sheath. The reinforcing sheet surrounds the cable body and prevents the cable body from being bitten by rats, squirrels, etc. and damaging the optical fibers. The rip cord is provided in the gap between the cable body and the reinforcing sheet, and is used to tear the reinforcing sheet and the outer sheath during disassembly of the optical fiber cable or intermediate and post-branching work.

Japanese Patent Application Publication No. 2017-72801

Incidentally, in recent years, short optical fiber cables having a total length of about 1 m, for example, are sometimes used. If the optical fiber cable is short like this, even if you try to tear the reinforcing sheet and outer sheath using the rip cord, the rip cord will accidentally come out from inside the optical fiber cable, making it impossible to perform the tearing process correctly. There was a case. In particular, in the configuration of Patent Document 1, the ripcord is disposed within the gap between the cable main body and the reinforcing sheet, and the ripcord easily comes off during the tearing operation.
Further, if the reinforcing sheet is rolled up and has an overlapping portion, and the rip cord is located inside the overlapping portion, the force required to tear the reinforcing sheet becomes extremely large. Therefore, when manufacturing an optical fiber cable, even if an attempt is made to position the ripcord at a position other than the inside of the overlapping portion of the reinforcing sheets, the configuration of Patent Document 1 does not stabilize the position of the ripcord, which is a factor that reduces manufacturing efficiency. It became.

The present invention has been made in consideration of these circumstances, and aims to improve the workability of tearing the reinforcing sheet and the outer sheath, and to improve the manufacturing efficiency of optical fiber cables.

In order to solve the above problems, an optical fiber cable according to a first aspect of the present invention includes a cable main body having a core and an inner sheath that accommodates the core, a reinforcing sheet surrounding the cable main body, and a reinforcing sheet surrounding the cable main body. and an outer sheath that accommodates the reinforcing sheet, and an outer ripcord embedded in the inner sheath, wherein the inner sheath is formed with a protrusion that protrudes radially outward, and the outer ripcord At least a portion of the protrusion is located inside the protrusion.

According to the first aspect, the outer rip cord for tearing the reinforcing sheet and the outer sheath is embedded in the inner sheath. Therefore, the pulling force when pulling out the outer rip cord from inside the optical fiber cable becomes large, and it is possible to prevent the outer rip cord from accidentally coming off during the tearing operation. Furthermore, since at least a portion of the outer ripcord is located inside the protrusion, the outer ripcord can be taken out to the outside of the outer sheath by holding the outer ripcord together with the protrusion using a tool or the like. . Therefore, the tearing operation using the outer rip cord can be easily performed.
Furthermore, because the outer ripcord is fixed within the inner sheath, the position of the outer ripcord is stabilized during manufacturing of the fiber optic cable. This makes it easy to manufacture the optical fiber cable so that the outer ripcord is located in a region excluding the inside of the overlapping portion of the reinforcing sheets, and manufacturing efficiency can be improved.

According to the above aspect of the present invention, it is possible to improve the tearing workability of the reinforcing sheet and the outer sheath, and to improve the manufacturing efficiency of the optical fiber cable.

FIG. 1 is a cross-sectional view of the optical fiber cable according to the first embodiment. FIG. 3 is a cross-sectional view of an optical fiber cable according to a second embodiment. FIG. 3 is a diagram illustrating the work of taking out a core from the optical fiber cable of FIG. 2. FIG. FIG. 7 is a cross-sectional view of an optical fiber cable according to a modification of the second embodiment. FIG. 7 is a cross-sectional view of an optical fiber cable according to a third embodiment. FIG. 7 is a cross-sectional view of an optical fiber cable according to a fourth embodiment. FIG. 7 is a cross-sectional view of an optical fiber cable according to a modification of the fourth embodiment. It is a cross-sectional view of the optical fiber cable concerning a 5th embodiment. FIG. 7 is a cross-sectional view of an optical fiber cable according to a modification of the fifth embodiment. FIG. 7 is a cross-sectional view of an optical fiber cable according to another modification of the fifth embodiment.

(First embodiment)
Hereinafter, the configuration of the optical fiber cable according to the first embodiment will be explained with reference to FIG. 1. In each of the drawings used in the following explanation, the scale is changed as appropriate to make each member a recognizable size.
As shown in FIG. 1, the optical fiber cable 1A includes a cable main body 10A having an optical fiber, a reinforcing sheet 20, and an outer sheath 30.

In this embodiment, the longitudinal direction of the cable main body 10A is simply referred to as the longitudinal direction, and the central axis of the cable main body 10A is simply referred to as the central axis O. Further, a cross section perpendicular to the central axis O is called a cross section. In a cross-sectional view, the direction perpendicular to the central axis O is called the radial direction, and the direction around the central axis O is called the circumferential direction.

The cable main body 10A includes a core 11, a pair of outer rip cords 12, a pair of tensile strength members (tension members) 13, and an inner sheath 14.
Core 11 extends in the longitudinal direction. The core 11 is constructed by collecting a plurality of optical fibers. As the optical fiber constituting the core 11, an optical fiber, a coated optical fiber, a coated optical fiber, or the like can be used. The plurality of optical fibers constituting the core 11 are, for example, bundled together using a binding material. The plurality of optical fibers may be wrapped or covered with water-absorbing tape (sheet). The cross-sectional shape of the core 11 is not particularly limited, and may be circular, oval, or rectangular.

The pair of tensile strength members 13 are embedded in the inner sheath 14 so as to sandwich the core 11 in a cross-sectional view. Each tensile strength member 13 extends in the longitudinal direction. Each tensile strength member 13 may be arranged parallel to the core 11 in the longitudinal direction, or may be arranged in a spiral shape around the core 11.
The tensile strength body 13 has a role of protecting the optical fiber of the core 11 from the tension acting on the optical fiber cable 1A. The material of the tensile strength body 13 is, for example, a metal wire (such as a steel wire), a tensile strength fiber (such as an aramid fiber), or FRP. The tensile strength body 13 may be a single wire, or may be a plurality of wires bundled or twisted together.

In a cross-sectional view, a straight line connecting the centers of the pair of tensile strength members 13 is called a neutral line L. When the optical fiber cable 1A is bent in a direction perpendicular to the neutral line L (vertical direction in FIG. 1), the expansion and contraction of the tensile strength member 13 becomes smaller than when the optical fiber cable 1A is bent in other directions. . Therefore, it is relatively easy to bend the optical fiber cable 1A in a direction perpendicular to the neutral line L.
Note that the cable main body 10A may include three or more tensile strength members 13. When three or more tensile strength members 13 are arranged at equal intervals in the circumferential direction, the bending directionality of the cable main body 10A becomes smaller, and the optical fiber cable 1A can be made easier to handle.

The inner sheath 14 covers the core 11 and the pair of tensile strength members 13 all together. As the material for the inner sheath 14, resins such as polyethylene (PE) and polyvinyl chloride (PVC) can be used.
The inner sheath 14 is formed into a substantially cylindrical shape. A pair of protrusions 15 that protrude radially outward are formed on the outer peripheral surface of the inner sheath 14 . The inner sheath 14 and the pair of projections 15 are integrally formed by extrusion molding or the like. The pair of protrusions 15 are arranged at equal intervals in the circumferential direction. In a cross-sectional view, the pair of protrusions 15 are located on a straight line orthogonal to the straight line connecting the pair of tensile strength members 13. Each protrusion 15 is formed in a substantially semicircular shape when viewed in cross section.

The outer rip cord 12 is used during the operation of tearing the reinforcing sheet 20 and the outer sheath 30 (hereinafter simply referred to as tearing operation). The outer rip cord 12 is required to have mechanical strength (for example, tensile strength) to the extent that it can cut through the reinforcing sheet 20 and the outer sheath 30.
The pair of outer rip cords 12 are located on a straight line that is perpendicular to the straight line connecting the pair of tensile strength members 13 when viewed in cross section. Each outer ripcord 12 extends longitudinally. As the outer rip cord 12, a string made of twisted synthetic fibers such as polyester and aramid can be used. The outer ripcord 12 is embedded in the protrusion 15 of the inner sheath 14 and is located inside the protrusion 15. In this embodiment, the outer ripcord 12 is not exposed outside the protrusion 15 in a cross-sectional view. Therefore, even if the inner sheath 14 and the protrusion 15 are cooled in a water tank after being extruded, moisture can be prevented from penetrating into the outer ripcord 12.

The reinforcing sheet 20 extends in the longitudinal direction and is formed into a cylindrical shape surrounding the cable main body 10A. As the material of the reinforcing sheet 20, metals such as stainless steel, copper, and copper alloys can be used. Further, a fiber sheet using glass fiber, aramid fiber, or the like, FRP, or the like may be used as the reinforcing sheet 20. It is desirable that the reinforcing sheet 20 is in the form of a tape, for example, and its length direction is aligned with the length direction of the cable main body 10A. The thickness of the reinforcing sheet 20 is, for example, about 0.1 to 0.3 mm. By setting the thickness of the reinforcing sheet 20 within this range, it is possible to prevent the optical fibers of the core 11 from being damaged by eating damage by animals, and to facilitate the operation of tearing the reinforcing sheet 20 with the outer rip cord 12. .

The reinforcing sheet 20 surrounds the entire cable body 10A and is partially overlapped in the circumferential direction. The portion where the reinforcing sheets 20 are overlapped is called an overlapping portion 20a.
Here, the optical fiber cable 1A tends to bend in the direction perpendicular to the neutral line L, as described above. For this reason, for example, if the overlapping portion 20a is located on the neutral line L, the overlapping portion 20a and the outer sheath 30 will be relatively easy to move when handling the optical fiber cable 1A. When the overlapping portion 20a and the outer sheath 30 move relative to each other, the side edge 20b of the reinforcing sheet 20 on the outer peripheral side of the overlapping portion 20a may damage the inner surface of the outer sheath 30. Therefore, in the present embodiment, the side edge 20b of the reinforcing sheet 20 on the outer circumferential side of the overlapping portion 20a and the tensile strength body 13 are arranged at different positions in the circumferential direction in a cross-sectional view.
Furthermore, in the present embodiment, the entire overlapping portion 20a and the tensile strength member 13 are arranged at different positions in the circumferential direction when viewed in cross section. Thereby, the distance between the side edge 20b and the neutral line L increases, and damage to the inner surface of the outer sheath 30 can be more reliably suppressed.

A first adhesive film 21 is attached to the surface of the reinforcing sheet 20 facing the cable main body 10A, and a second adhesive film 22 is attached to the surface of the reinforcing sheet 20 facing the outer sheath 30. As the adhesive used for the first adhesive film 21 and the second adhesive film 22, for example, a thermosetting adhesive can be used. Note that the material of the adhesive may be changed as appropriate. The second adhesive film 22 has the role of fixing the outer sheath 30 to the reinforcing sheet 20. Furthermore, the portions of the first adhesive film 21 and the second adhesive film 22 located between the reinforcing sheets 20 at the overlapping portion 20a serve to fix the reinforcing sheets 20 to each other at the overlapping portion 20a.

The outer sheath 30 accommodates the cable main body 10A and the reinforcing sheet 20. The outer sheath 30 is formed into a cylindrical shape extending in the longitudinal direction. As the material of the outer sheath 30, resins such as polyethylene (PE) and polyvinyl chloride (PVC) can be used.

When taking out the core 11 from the optical fiber cable 1A, first, the outer sheath 30 and reinforcing sheet 20 are partially cut open using a tool such as a cutter. Next, a tool such as pliers is inserted through the cut portion, the outer ripcord 12 is held together with the protrusion 15, and the outer ripcord 12 is pulled out to the outside of the outer sheath 30. By this operation, the reinforcing sheet 20 and the outer sheath 30 are torn apart by the outer ripcord 12 extending in the longitudinal direction, and the cable main body 10A can be taken out. Then, by cutting open the cable main body 10A, the core 11 can be taken out.

According to the optical fiber cable 1A having the configuration described above, the outer rip cord 12 for tearing the reinforcing sheet 20 and the outer sheath 30 is embedded in the protrusion 15 of the inner sheath 14. Therefore, the pulling force when pulling out the outer rip cord 12 from inside the optical fiber cable 1A increases, and it is possible to prevent the outer rip cord 12 from accidentally coming off during the tearing operation. Therefore, the tearing operation using the outer rip cord 12 can be easily performed.

Further, since the outer rip cord 12 is fixed within the protrusion 15, the position of the outer rip cord 12 is stabilized during manufacturing of the optical fiber cable 1A. This makes it easy to manufacture the optical fiber cable 1A so that the outer ripcord 12 is located in a region excluding the radially inner side of the overlapping portion 20a of the reinforcing sheet 20, and manufacturing efficiency can be improved.

(Second embodiment)
Next, a second embodiment according to the present invention will be described, which has the same basic configuration as the first embodiment. Therefore, similar configurations will be given the same reference numerals and their explanations will be omitted, and only the different points will be explained.
The optical fiber cable 1B of the second embodiment is a further improvement of the optical fiber cable 1A of the first embodiment, and the work of taking out the core 11 after tearing the reinforcing sheet 20 and the outer sheath 30 is required. It's getting easier.

As shown in FIG. 2, the cable main body 10B of this embodiment includes a pair of inner ripcords 16 in addition to a pair of outer ripcords 12. The inner ripcord 16 is embedded in a radially inner portion of the protrusion 15 and the outer ripcord 12 in the inner sheath 14 . Therefore, the wall thickness of the root portion 15b of the protrusion 15 is reduced, and the protrusion 15 is easily broken starting from the root portion 15b and separated from the inner sheath 14.

The inner ripcord 16 is in contact with the core 11. When the outer diameter of the inner ripcord 16 is d and the thickness of the portion of the inner sheath 14 where the protrusion 15 is not formed is t, d≧t is satisfied. Note that the optical fiber cable 1B does not need to satisfy d≧t.
As the material of the inner rip cord 16, in addition to strings made of synthetic fibers such as polyester and aramid, cylindrical rods made of PP or nylon can be used.

The protrusion 15 of this embodiment is formed into a substantially rectangular shape when viewed in cross section. In a cross-sectional view, the side surface 15a of the protrusion 15 is formed into a straight line. Further, the side surface 15a is inclined such that the width W of the protrusion 15 in the circumferential direction gradually increases toward the outside in the radial direction. That is, the side surface 15a of the protrusion 15 is formed in a so-called reverse tapered shape. As a result, tensile stress tends to concentrate on the root portion 15b of the protrusion 15.

Next, a procedure for taking out the core 11 from the optical fiber cable 1B having the above configuration will be explained.

First, the outer sheath 30 and reinforcing sheet 20 are partially cut using a tool such as a cutter. Next, as shown in FIG. 3(a), an existing tool K such as pliers is inserted into the reinforcing sheet 20 through the cut portion. Then, the outer ripcord 12 is held together with the protrusion 15 using the tool K. At this time, since the width W in the circumferential direction of the protrusion 15 gradually increases toward the outside in the radial direction, the tool K holding the protrusion 15 is difficult to come off from the protrusion 15.

Next, as shown in FIG. 3(b), the tool K is pulled up while holding the protrusion 15. As a result, tensile stress is concentrated on the root portion 15b of the protrusion 15, and a break occurs starting from the root portion 15b, and the protrusion 15 and the inner sheath 14 are separated. Thereby, the outer ripcord 12 together with the projection 15 can be pulled out to the outside of the outer sheath 30. Then, by continuing to pull up the outer ripcord 12, the reinforcing sheet 20 and the outer sheath 30 can be torn by the outer ripcord 12.

When tearing the reinforcing sheet 20 and the outer sheath 30 along the longitudinal direction using the outer ripcord 12, the projections 15 are pulled away from the inner sheath 14 together with the outer ripcord 12. Therefore, the protrusion 15 is also separated from the inner sheath 14 along the longitudinal direction.
Here, the inner ripcord 16 is in contact with the core 11, and the outer diameter d of the inner ripcord 16 is greater than or equal to the thickness t of the inner sheath 14. Therefore, when the protrusion 15 and the internal sheath 14 are separated along the longitudinal direction, the internal sheath 14 is automatically divided into two parts as shown in FIG. 3(c). Thereby, the core 11 can be easily taken out.

As described above, according to the optical fiber cable 1B of this embodiment, the inner rip cord 16 is arranged in addition to the outer rip cord 12, and the outer rip cord 12 is used to connect the reinforcing sheet 20 and the outer sheath 30. By tearing, the inner sheath 14 is automatically divided into two parts. Therefore, the core 11 can be easily taken out during the dismantling work of the optical fiber cable 1B, the intermediate branching work, etc., and the work efficiency can be improved.

Further, the width W of the protrusion 15 in the circumferential direction increases toward the outside in the radial direction. This configuration makes it easier to hold the protrusion 15 with the tool K, and also makes it easier for tensile stress to concentrate on the root portion 15b of the protrusion 15. Therefore, it becomes easier to pull out the outer ripcord 12 together with the protrusion 15 to the outside of the outer sheath 30.

In addition, since the inner diameter d of the inner rip cord 16 and the thickness t of the inner sheath 14 satisfy d≧t, when the protrusion 15 and the inner sheath 14 are separated, the inner sheath 14 can be divided more reliably. can be done.

In FIG. 2, the pair of inner ripcords 16 and the pair of outer ripcords 12 are arranged on a straight line in a cross-sectional view, but the present invention is not limited to this. For example, as shown in FIG. 4, the outer ripcord 12 may be disposed at a circumferentially offset position with respect to the inner ripcord 16. Even in this case, since the wall thickness of the protrusion 15 at the root portion 15b is thinner, breakage is likely to occur starting from the root portion 15b, and the inner ripcord 16 can be easily exposed.

(Third embodiment)
Next, a third embodiment according to the present invention will be described, which has the same basic configuration as the second embodiment. Therefore, similar configurations will be given the same reference numerals and their explanations will be omitted, and only the different points will be explained.
In this embodiment, the waterproof performance is enhanced in consideration of the case where the optical fiber cable is installed outdoors or the case where the inner sheath 14 and the protrusion 15 are cooled by being immersed in a water tank during extrusion molding. In particular, when the outer rip cord 12 and the inner rip cord 16 are in the form of strings made of twisted fibers, moisture can penetrate into the outer rip cord 12 and the inner rip cord 16, causing water running inside the cable body. There is a risk that the product may become damaged.

Therefore, in the optical fiber cable 1C of this embodiment, as shown in FIG. 5, the outer rip cord 12 is covered with a coating 12a. The material for the coating 12a is preferably one that does not allow moisture to pass through. For example, the coating 12a may be formed by applying adhesive resin to the outer periphery of the outer ripcord 12.

According to this embodiment, even if the outer ripcord 12 is partially exposed from the protrusion 15 as shown in FIG. 5, moisture is prevented from entering the inside of the protrusion 15 through this exposed part. can do. Therefore, it is possible to prevent water from running inside the cable main body 10C and improve waterproof performance.

(Fourth embodiment)
Next, a fourth embodiment according to the present invention will be described, which has the same basic configuration as the second embodiment. Therefore, similar configurations will be given the same reference numerals and their explanations will be omitted, and only the different points will be explained. In the first to third embodiments, the protrusion 15 protrudes radially outward from the outer peripheral surface of the cylindrical inner sheath 14. In this embodiment, the inner sheath 14 has a cylindrical shape with a portion removed, thereby forming a protrusion.

As shown in FIG. 6, in the optical fiber cable 1D (cable main body 10D) of the present embodiment, a first groove 14a1 and a second groove 14a2 are recessed radially inward on the outer peripheral surface of the cylindrical inner sheath 14. is formed. The first groove portion 14a1 and the second groove portion 14a2 are arranged at intervals in the circumferential direction. A portion of the inner sheath 14 between the first groove portion 14a1 and the second groove portion 14a2 has a shape that projects radially outward. That is, in this embodiment, the first projection 17a is formed by the pair of grooves 14a1 and 14a2.

Further, a third groove portion 14a3 and a fourth groove portion 14a4 are formed on the radially opposite sides of the groove portions 14a1 and 14a2 that sandwich the core 11 therebetween. The third groove portion 14a3 and the fourth groove portion 14a4 are recessed from the outer circumferential surface of the inner sheath 14 toward the inside in the radial direction, and are spaced apart from each other in the circumferential direction. A portion of the inner sheath 14 between the third groove portion 14a3 and the fourth groove portion 14a4 has a shape that projects radially outward. In other words, the second protrusion 17b is formed by the pair of grooves 14a3 and 14a4 arranged on the radially opposite side of the pair of grooves 14a1 and 14a2.

The inner surfaces of the grooves 14a1 to 14a4 are formed into curved surfaces that are convex toward the inside in the radial direction. Note that the shapes of the grooves 14a1 to 14a4 may be changed as appropriate. For example, the grooves 14a1 to 14a4 may have a triangular or rectangular shape when viewed in cross section. Furthermore, the shapes of the grooves 14a1 to 14a4 may be different from each other.

A pair of grooves 14a1 and 14a2 forming the first protrusion 17a are arranged to sandwich the outer ripcord 12 in the circumferential direction. Similarly, the pair of grooves 14a3 and 14a4 forming the second projection 17b are arranged to sandwich the outer ripcord 12 in the circumferential direction. As a result, at least a portion of the outer ripcord 12 is located inside the first protrusion 17a or the second protrusion 17b.
The first protrusion 17a and the second protrusion 17b extend in the longitudinal direction. Also in this embodiment, the outer ripcord 12 can be pulled out to the outside of the outer sheath 30 by holding and pulling up the first protrusion 17a or the second protrusion 17b with the tool K (FIGS. 3(a) to 3(a)). c).

In this embodiment, the pair of inner ripcords 16, the pair of outer ripcords 12, and the pair of protrusions 17a and 17b are arranged in a straight line in a cross-sectional view. However, this arrangement may be changed as appropriate. For example, as shown in FIG. 7, the protrusions 17a, 17b (outer rip cord 12) may be arranged at different positions from the inner rip cord 16 in the circumferential direction.

(Fifth embodiment)
Next, a fifth embodiment according to the present invention will be described, but the basic configuration is the same as that of the fourth embodiment. For this reason, similar configurations are given the same reference numerals and explanations thereof will be omitted, and only the different points will be explained.
As shown in FIG. 8, in the optical fiber cable 1E (cable main body 10E) of this embodiment, the inner sheath 14 is formed with a plurality of flat surfaces 14b1 to 14b4. The inner sheath 14 has a cylindrical shape with a portion of its outer peripheral surface cut out. The first flat surface 14b1 and the second flat surface 14b2 are arranged to sandwich the first projection 17a in the circumferential direction. It can also be said that the first protrusion 17a is formed by a pair of flat surfaces 14b1 and 14b2. Similarly, the third flat surface 14b3 and the fourth flat surface 14b4 are arranged to sandwich the second projection 17b in the circumferential direction. It can also be said that the second projection 17b is formed by a pair of flat surfaces 14b3 and 14b4.

The first protrusion 17a and the second protrusion 17b extend along the longitudinal direction. Also in this embodiment, at least a portion of the outer ripcord 12 is located inside the first protrusion 17a or the second protrusion 17b. Therefore, by holding the first protrusion 17a or the second protrusion 17b with the tool K and pulling it up, the outer ripcord 12 can be pulled out to the outside of the outer sheath 30 (FIGS. 3(a) to 3(c)). reference).

The flat surfaces 14b1 to 14b4 extend along the longitudinal direction. Further, in a cross-sectional view, the flat surfaces 14b1 to 14b4 extend substantially parallel to the neutral line L. However, the shape and arrangement of the flat surfaces 14b1 to 14b4 may be changed as appropriate. For example, as shown in FIG. 9, the flat surfaces 14b1 to 14b4 may be inclined surfaces gradually radially inward toward the outer ripcord 12 in the circumferential direction. Further, similar to FIG. 7 in the fourth embodiment, the protrusions 17a and 17b (outer rip cord 12) may be arranged at different positions from the inner rip cord 16 in the circumferential direction.

Note that the technical scope of the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.

For example, in the embodiment, two protrusions 15, two outer rip cords 12, and two inner rip cords 16 were provided, but these numbers may be changed as appropriate.

In addition, the components in the embodiments described above can be replaced with well-known components as appropriate without departing from the spirit of the present invention, and the embodiments and modifications described above may be combined as appropriate.

For example, the shape of the protrusion 15 in the second embodiment may be applied to the optical fiber cable 1A in the first embodiment. Even in this case, the same effects as those described in the second embodiment can be obtained.
Moreover, the outer rip cord 12 in the optical fiber cable 1A of the first embodiment may be covered with a coating 12a.

In addition, by combining the third embodiment and the fifth embodiment, as shown in FIG. The rip cord 12 may be exposed. The outer ripcord 12 may also be covered with a coating 12a. In this case, the outer rip cord 12 becomes easier to take out, and even if the cable main body 10E is immersed in cooling water during manufacturing, water is prevented from entering the inside of the outer rip cord 12 and the insides of the protrusions 17a and 17b. It will be done.

1A to 1E...Optical fiber cable 10A to 10E...Cable body 11...Core 12...Outer rip cord 12a...Coating 13...Tension member 14...Inner sheath 14a1 to 14a4...Groove portion 14b1 to 14b4...Flat surface 15...Protrusion portion 16...Inner side Ripcord 17a, 17b...Protrusion 20...Reinforcement sheet 30...Outer sheath

Claims (8)

A cable body having a core and an inner sheath that accommodates the core, a reinforcing sheet that surrounds the cable body, an outer sheath that accommodates the cable body and the reinforcing sheet, and an outer rip cord embedded in the inner sheath. A method for disassembling an optical fiber cable, wherein at least a portion of the outer ripcord is located inside a protrusion projecting radially outward from the inner sheath,
A method for disassembling an optical fiber cable, wherein the outer ripcord is held together with the protrusion and pulled out of the outer sheath to tear the reinforcing sheet and the outer sheath and take out the cable main body. a cable body having a core and an inner sheath housing the core;
a reinforcing sheet surrounding the cable main body;
an outer sheath that accommodates the cable main body and the reinforcing sheet;
an outer ripcord embedded in the inner sheath;
The inner sheath is formed with a protrusion that protrudes radially outward,
at least a portion of the outer ripcord is located inside the protrusion;
An inner rip cord is embedded in a portion of the inner sheath that is radially inner than the outer rip cord,
An optical fiber cable, wherein at least a portion of the outer ripcord is located radially outward of the protrusion. a cable body having a core and an inner sheath housing the core;
a reinforcing sheet surrounding the cable main body;
an outer sheath that accommodates the cable main body and the reinforcing sheet;
an outer ripcord embedded in the inner sheath;
The inner sheath is formed with a protrusion that protrudes radially outward,
at least a portion of the outer ripcord is located inside the protrusion;
An inner ripcord is embedded in a portion of the inner sheath that is radially inner than the outer ripcord and overlaps at least a portion of the outer ripcord in the circumferential direction,
An optical fiber cable, wherein the outer ripcord and the inner ripcord are spaced apart in a radial direction. The optical fiber cable according to claim 2 or 3, wherein the outer circumferential surface of the inner sheath is circular in cross-sectional view, and the side surface of the protrusion is linear. The optical fiber cable according to any one of claims 2 to 4, wherein the width of the protrusion in the circumferential direction gradually increases toward the outside in the radial direction. When the outer diameter of the inner ripcord is d, and the thickness of the portion of the inner sheath where the protrusion is not formed is t,
The optical fiber cable according to any one of claims 2 to 5, satisfying d≧t. The optical fiber cable according to any one of claims 2 to 6, wherein a pair of flat surfaces are formed on the outer peripheral surface of the inner sheath so as to sandwich the protrusion in the circumferential direction. 8. A fiber optic cable according to any one of claims 2 to 7, wherein the outer ripcord is covered with a jacket.

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