JP2012042715A - Optical fiber cable and method for taking out the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable allowing easy take-out of an optical fiber by peeling off metal tapes and sheaths from a slot core.SOLUTION: A sheath 6 coating the whole of a slot core 4 is made to have a multilayer structure including a first sheath 6A, a second sheath 6B and a third sheath 6C from the inside of an optical fiber cable toward the outside. A metal tape 7 is made to have a divided structure including a first metal tape 7A and a second metal tape 7B covering at least a semicircle of the slot core 4, respectively. The first metal tape 7A and the second metal tape 7B are arranged to be wound by one round as a whole around the slot core 4 without being brought into contact with each other. The optical fiber cable is made to have a cable structure coating the slot core 4 by the first sheath 6A, the first metal tape 7A, the second sheath 6B, the second metal tape 7B and the third sheath 6C in this order from the inside of the optical fiber cable toward the outside.

Description

  The present invention relates to an optical fiber cable in which a metal tape is provided on a sheath covering a slot core containing an optical fiber, and an optical fiber extraction method for extracting an optical fiber from the optical fiber cable.

  For example, an optical fiber cable wired outdoors may be damaged due to a hole being formed in a sheath (jacket) covering a slot core in which the optical fiber is accommodated by birds or insects. is there. For this reason, an optical fiber cable has been proposed in which a metal tape is wound around a slot core and covered with a sheath to protect the optical fiber stored in the slot core (see, for example, Patent Document 1).

  In the optical fiber cable described in Patent Document 1, after winding a metal tape so as to cover the entire circumference of the slot core, the ends of the metal tape are welded into a circular shape so that the entire slot core is formed. It protects with the said metal tape.

JP 2004-20833 A

  However, in the optical fiber cable described in Patent Document 1, since the metal tape is wound around the entire outer periphery of the slot core, the work of taking out the optical fiber from the slot core by cutting the metal tape and sheath having a circular cross-section into a ring shape. This is extremely difficult and requires a lot of time for the intermediate branching work. In particular, when the sheath is torn longitudinally along the cable longitudinal direction at the time of intermediate branching, the metal tape must also be cut, which makes it difficult to cut the metal tape.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical fiber cable and an optical fiber extraction method capable of easily removing an optical fiber by peeling off a metal tape and a sheath from a slot core.

  According to the first aspect of the present invention, there is provided a slot core that stores and holds an optical fiber in a slot groove, a sheath that covers the entire slot core including the opening of the slot groove, and a longitudinal direction of the cable in the sheath. In an optical fiber cable including a metal tape vertically attached, the sheath has a multilayer structure including a first sheath, a second sheath, and a third sheath from the inside to the outside of the cable, and the metal tape includes: A divided structure including a first metal tape and a second metal tape covering at least half of the circumference of the slot core, and the first metal tape and the second metal tape are entirely disposed around the slot core without contacting each other. The first sheath, the first metal tape, the second sheath, and the second metal tape are arranged so as to be wound once around from the inside to the outside of the cable. It is characterized in the order of 3 sheath that covers the slotted core.

  A second aspect of the present invention is the optical fiber cable according to the first aspect, wherein each of the first metal tape and the second metal tape is continuously waved along the longitudinal direction of the cable. It is characterized by having.

  Invention of Claim 3 is an optical fiber cable of Claim 1 or Claim 2, Comprising: Each sheath is along a cable longitudinal direction to said 1st sheath, 2nd sheath, and said 3rd sheath. It is characterized by providing a marker for vertical tearing with a cutter.

  According to a fourth aspect of the present invention, in the optical fiber take-out method for taking out an optical fiber from the optical fiber cable according to the third aspect, a cutter is cut into the third sheath at a first position in the longitudinal direction of the optical fiber cable. After the third sheath is cut into a circle along the cable circumferential direction, the cutter is cut into the third sheath along the marker provided on the third sheath to make a longitudinal tear, and further, the end position is the longitudinal tear. A third sheath stripping step of stripping the second metal tape together with the third sheath by cutting the cutter into the third sheath again at the second position and cutting the third sheath into a ring along the circumferential direction of the cable. And cutting the cutter into the second sheath at the first position to cut the second sheath along the circumferential direction of the cable, and then setting the second sheath on the second sheath. A cutter is cut into the second sheath along the marker so as to be longitudinally split, and the cutter is cut again into the second sheath at the second position, and the second sheath is cut along the circumferential direction of the cable. The second sheath stripping step for stripping the first metal tape together with the second sheath, and cutting the cutter into the first sheath at the first position and cutting the first sheath along the circumferential direction of the cable. Then, a cutter is cut into the first sheath along the marker provided on the first sheath to make a vertical tear, and the cutter is cut again into the first sheath at the second position. Is cut along the circumferential direction of the cable to peel off the first sheath, and the first sheath is peeled off. DOO groove is opened to the outside is characterized by having a an optical fiber extraction step of taking out the optical fiber from the slot groove.

  The invention according to claim 5 is the optical fiber take-out method according to claim 4, wherein when the third sheath is longitudinally split in the third sheath stripping step, only the third sheath is cut with a cutter. When the second sheath is torn vertically in the two-sheath stripping process, only the second sheath is torn with a cutter.

  According to a sixth aspect of the present invention, there is provided a slot core that accommodates and holds an optical fiber in a slot groove, a sheath that covers the entire slot core including the opening of the slot groove, and a longitudinal direction of the cable in the sheath. In an optical fiber cable having a metal tape vertically attached, the sheath has a multi-layer structure having a first sheath and a second sheath from the inside to the outside of the cable, and the metal tape is formed on the slot core. The first metal tape and the second metal tape that cover at least half of the circumference are divided, and the first metal tape and the second metal tape are wound around the slot core as a whole without contacting each other. And a first metal tape, a first sheath, and a second metal tape around the outer periphery of the slot core from the inside to the outside of the cable. It is characterized in that covering the slotted core in the order of the second sheath.

  According to the optical fiber cable of the present invention, the metal tape is divided into a first metal tape and a second metal tape covering at least half of the circumference of the slot core, and the metal tape is surrounded by the slot core without contacting each other. Since each of the sheaths having a multilayer structure is interposed between the metal tapes, the metal tape is also peeled off together when the sheaths are sequentially peeled off. As compared with the case where the entire slot core is covered with the metal tape, an optical fiber cable structure can be obtained in which the sheath stripping operation can be easily performed.

  According to the optical fiber take-out method of the present invention, when the outermost third sheath of the cable is cut off by being cut and longitudinally cut, the second metal tape is also peeled off together with the third sheath. When the second sheath inside the third sheath is cut off and cut off in a longitudinal direction, the first metal tape is also peeled off together with the second sheath. Then, when the innermost first sheath of the cable is cut and peeled off, the slot groove is opened outward, and the optical fiber in the slot groove can be taken out. As described above, according to the present invention, when each sheath having a multilayer structure is peeled off, each metal tape having a divided structure is also peeled off. Therefore, the sheath is peeled as compared with the case where the entire slot core is covered with one metal tape. The taking operation can be easily performed. As a result, according to the present invention, the intermediate branching operation can be performed in a short time.

FIG. 1 is a perspective view showing a partially broken optical fiber cable of the present embodiment. FIG. 2 is a perspective view of a metal tape used in the optical fiber cable of FIG. FIG. 3 is a process diagram showing a third sheath stripping step and a second sheath stripping step in the optical fiber extraction method of the present embodiment. FIG. 4 is a perspective view showing an optical fiber extraction step in the optical fiber extraction method of the present embodiment. FIG. 5 is a cross-sectional view of an optical fiber cable according to another embodiment of the present embodiment.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[Description of optical fiber cable structure]
FIG. 1 is a perspective view showing a partially broken optical fiber cable of the present embodiment, and FIG. 2 is a perspective view of a metal tape used for the optical fiber cable of FIG.

  As shown in FIG. 1, the optical fiber cable 1 of the present embodiment includes a slot core 4 that contains and holds the optical fiber 2 in the slot groove 3, and the slot core 4 including the opening 5 of the slot groove 3. It consists of a sheath 6 covering the whole and a metal tape 7 vertically attached in the longitudinal direction of the cable in the sheath 6.

  For the optical fiber 2, an optical fiber, an optical fiber, an optical fiber tape, or the like is used. The optical fiber is a quartz glass fiber coated with an ultraviolet curable resin. The optical fiber core is a silica glass fiber coated with a plastic resin and has a diameter larger than that of the optical fiber. The optical fiber ribbon is made of several optical fiber strands arranged in parallel and covered with an ultraviolet curable resin. In FIG. 1, an optical fiber ribbon is used, and a plurality of (8) optical fiber ribbons are accommodated in the slot groove 3. An interference material may be interposed between the optical fiber 2 and the slot groove 3, or a gap may be provided.

  The slot core 4 is a holding member that accommodates and holds the optical fiber 2 therein, and has a slot groove 3 that is a circular arc having a center point at a position shifted from the center point C of the optical fiber cable 1. Yes. The slot core 4 is formed by extrusion molding, and a cross section perpendicular to the longitudinal direction has a C-shaped cross section. The slot core 4 is not uniform in thickness, and gradually increases in thickness from the part where the opening 5 is formed to the part opposite to the opening 5. In other words, the thickness of the slot core 4 gradually decreases from the portion corresponding to the bottom of the slot groove 3 to the portion where the opening 5 is formed.

  In addition, the slot core 4 has two cables in order to prevent the sheath 6 from being thermally contracted by the influence of heat received at the place where the optical fiber cable 1 is laid and the optical fiber cable 1 itself being deformed. Strength members 8 and 8 are embedded. The strength member 8 is made of, for example, a wire such as steel wire or FRP, and is provided in the slot core 4 along the cable longitudinal direction.

  The sheath 6 has a multilayer structure including a first sheath 6A, a second sheath 6B, and a third sheath 6C from the inside to the outside of the cable. The first sheath 6A is thick at the portion corresponding to the slot groove 5 and thin at the portion corresponding to the strength member 8, and has a non-uniform thickness structure as a whole. The second sheath 6B is thinner than the first sheath 6A and the third sheath 6C, and is interposed between the first metal tape 6A and the second metal tape 6B. The third sheath 6C is provided on the outermost side of the cable and has a substantially uniform thickness.

  The sheath 6 is formed by extrusion molding so that the entire outer periphery of the slot core 4 housing the optical fiber 2 is covered with a polyethylene resin. When the first sheath 6A is formed, a pressing tape 9 for preventing the polyethylene resin from entering the slot groove 3 is attached in the longitudinal direction of the cable so as to close the opening 5. When the second sheath 6B is formed, the first metal tape 7A is disposed on the first sheath 6A and the polyethylene resin is extruded and formed. When the third sheath 6C is formed, the second metal tape 7B is disposed on the second sheath 6B and a polyethylene resin is extruded and formed.

  Each of the first sheath 6A, the second sheath 6B, and the third sheath 6C has markers M1, M2, and M3 (first marker M1, second marker) for longitudinally tearing each sheath 6 with a cutter along the cable longitudinal direction. A marker M2 and a third marker M3) are provided. The positions of the markers M 1, M 2, and M 3 can be immediately recognized with a color different from that of the sheath 6.

  The metal tape 7 has a divided structure composed of two metal tapes, a first metal tape 7A and a second metal tape 7B, covering at least a half circumference of the slot core 4. The first metal tape 7 </ b> A and the second metal tape 7 </ b> B are both arcuate in cross section so that they can be covered a little more than the half circumference of the slot core 4 when they are arranged around the outer periphery of the slot core 4. It has a long shape. As shown in FIG. 2, the first and second metal tapes 7A and 7B are formed into a circular arc shape by forming a wave portion 10 having a shape that continuously undulates along a cable longitudinal direction on a thin stainless steel plate. Is formed. The wave portion 10 is formed so as to protrude outward as viewed from the slot core 4. By forming the wave portion 10, the optical fiber cable 1 can be easily bent.

  In the optical fiber cable 1 including the above components, the first sheath 6A, the first metal tape 7A, the second sheath 6B, the second metal tape 7B, and the third sheath 6C are arranged in this order from the inside to the outside of the cable. The slot core 4 is covered. The first metal tape 7 </ b> A is disposed so as to cover the slot core 4 on the side where the opening 5 of the slot groove 3 is provided in half a circle. On the other hand, the 2nd metal tape 7B is arrange | positioned so that the slot core 4 of the side in which the tension body 8 is provided may be covered by a half circumference. Further, the first metal tape 7A and the second metal tape 7B are arranged so as to be wound around the slot core 4 as a whole without contacting each other. In FIG. 1, both ends forming an arc of the first metal tape 7A and the second metal tape 7B overlap (overlap) each other.

[Explanation of optical fiber extraction method]
Next, an optical fiber extraction method for extracting the optical fiber 2 from the optical fiber cable 1 having the above configuration will be described.

  FIG. 3 is a process diagram showing a third sheath stripping process and a second sheath stripping process in the optical fiber extracting method of the present embodiment, and FIG. 4 shows an optical fiber extracting process in the optical fiber extracting method of the present embodiment. It is a perspective view.

  In order to take out the optical fiber 2 from the optical fiber cable 1, a third sheath stripping step for stripping the third sheath 6C and the second metal tape 7B, and a second sheath stripping for stripping the second sheath 6B and the first metal tape 7A. The optical fiber 2 is taken out from the slot groove 3 by sequentially performing the removing step and the first sheath peeling step for peeling off the first sheath 6A.

  First, a third sheath stripping process is performed. In the third sheath stripping step, the cutter 11 is cut into the third sheath 6C as shown in FIG. 3A at an arbitrary position (first position) where the optical fiber cable 1 branches in the longitudinal direction. At this time, the cutting edge of the cutter 11 is pierced to a position reaching the second sheath 6B. Then, the cutter 11 is moved along the cable circumferential direction indicated by the arrow X in FIG. At that time, the second metal tape 7 </ b> B is also cut into circles by the cutter 11. The metal tape 7 is hard unlike a resin because it is formed of a thin stainless steel plate. However, the metal tape 7 is longer in the cable circumferential direction than in the cable longitudinal direction, which requires a relatively long longitudinal tear for the intermediate branch. Cutting is shorter and easier to cut.

  Next, the cutter 11 is cut into the third sheath 6C along the third marker M3 provided on the third sheath 6C, and the intermediate branching portion is vertically split. At the time of this vertical tearing, the cutting edge of the cutter 11 is pierced to a position reaching the second sheath 6B. At the time of vertical tearing by the cutter 11, it is not necessary to tear only the third sheath 6C, which is a resin, and to cut the first metal tape 7A and the second metal tape 7B. Further, the cutter 11 is cut again into the third sheath 6C at the second position which is the longitudinally ending end position, and the third sheath 6C is cut along the circumferential direction of the cable. When the cut third sheath 6C is opened from the longitudinally cut portion and peeled off from the slot core 4, the second metal tape 7B is peeled off together with the third sheath 6C as shown in FIG. 3B.

  Next, a second sheath stripping process is performed. In the second sheath stripping step, the cutter 11 is cut into the second sheath 6B at the first position as shown in FIG. At this time, the cutting edge of the cutter 11 is pierced to a position where it breaks through the first metal tape 7A and reaches the first sheath 6A. Then, the cutter 11 is moved along the cable circumferential direction indicated by the arrow X in FIG. At that time, the first metal tape 7 </ b> A is also cut into a circle by the cutter 11.

  Next, the cutter 11 is cut into the second sheath 6B along the second marker M2 provided on the second sheath 6B, and the portion that is branched in the middle is split into vertical portions. At the time of this vertical tearing, the cutting edge of the cutter 11 is pierced to a position reaching the first sheath 6A. At the time of vertical tearing by the cutter 11, it is not necessary to tear only the second sheath 6B, which is a resin, and to cut the second metal tape 7B. Further, the cutter 11 is cut again into the second sheath 6B at the second position, which is the longitudinally ending end position, and the second sheath 6B is cut along the circumferential direction of the cable. When the cut second sheath 6B is opened from the longitudinally cut portion and peeled off from the slot core 4, the first metal tape 7A is peeled off together with the second sheath 6B as shown in FIG. As a result, the slot 6 can be taken out by peeling the sheath 6 together with the first metal tape 7A and the second metal tape 7B.

  Next, a first sheath stripping process is performed. In the first sheath stripping step, the cutter 11 is cut into the first sheath 6A at the first position as shown in FIG. At this time, the cutting edge of the cutter 11 is inserted to a position reaching the slot core 4. Then, the cutter 11 is moved along the cable circumferential direction indicated by the arrow X in FIG.

  Next, the cutter 11 is cut into the first sheath 6A along the first marker M1 provided on the first sheath 6A, and the portion that is branched in the middle is vertically split. FIG. 4 (B) shows a state in which it has been longitudinally split. At the time of this vertical tearing, the cutting edge of the cutter 11 is inserted to a position reaching the opening 5 of the slot groove 3. Further, the cutter 11 is cut again into the first sheath 6A at the second position which is the longitudinally ending end position, and the first sheath 6A is cut into a ring along the cable circumferential direction. The cut first sheath 6A is opened from the longitudinally cut portion as shown in FIG. Then, as shown in FIG. 4D, the slot core 4 is exposed and the optical fiber 2 can be taken out from the slot groove 3.

[Operational effects of this embodiment]
According to the optical fiber cable of the present embodiment, the metal tape 7 is divided into a first metal tape 7A and a second metal tape 7B that cover at least a half circumference of the slot core 4, and the metal tapes 7A and 7B are mutually connected. Since the sheaths 6A, 6B, 6C having a multilayer structure are arranged around the slot core 4 without being in contact with each other, the sheaths 6A, 6B are arranged so as to be wound around as a whole. In addition, since the metal tapes 7A and 7B are also peeled off together, an optical fiber cable structure is provided in which the sheath stripping operation can be easily performed as compared with the case where the entire slot core 4 is covered with a single metal tape 7. be able to.

  Moreover, according to the optical fiber cable of this embodiment, since both the 1st metal tape 7A and the 2nd metal tape 7B are made into the shape which waves continuously along a cable longitudinal direction, this cable part 10 It becomes easy to bend.

  Further, according to the optical fiber cable of the present embodiment, each of the sheaths 6A, 6B, 6C is longitudinally split by the cutter 11 along the cable longitudinal direction on the first sheath 6A, the second sheath 6B, and the third sheath 6C. Since the markers M1, M2, and M3 are provided, it is only necessary to cut the cutter 11 along the markers M1, M2, and M3, and the vertical tearing operation can be easily performed.

  Further, according to the optical fiber take-out method of the present embodiment, when the outermost third sheath 6C of the cable is cut off by being cut and longitudinally cut, the second metal tape 7B is also peeled off together with the third sheath 6C. In addition, when the second sheath 6B inside the third sheath 6C is cut off by being cut in a round shape and vertically cut, the first metal tape 7A is also peeled off. When the innermost first sheath 6A of the cable is cut and peeled off, the slot groove 3 is opened outward, and the optical fiber 2 in the slot groove 3 can be taken out. As described above, according to the present invention, when the sheaths 6A and 6B having a multilayer structure are peeled off, the metal tapes 7A and 7B having a split structure are also peeled off. Compared to the case of covering the sheath, the sheath stripping operation can be easily performed. As a result, according to the present invention, the intermediate branching operation can be performed in a short time.

  Further, according to the optical fiber extraction method of the present embodiment, when the third sheath 6C is torn longitudinally in the third sheath stripping process, only the third sheath 6C is torn by the cutter 11, and the second sheath stripping process is performed. When the second sheath 6B is torn longitudinally, only the second sheath 6B is torn by the cutter 11, and therefore it is not necessary to longitudinally tear the hard first metal tape 7A and the second metal tape 7B in any sheath stripping process. 6 can be easily removed, and the operation time can be shortened.

  Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  For example, in the optical fiber cable 1 of the above-described embodiment, the present invention is applied to a so-called C slot type optical fiber cable in which the optical fiber 4 is accommodated in the slot groove 3 formed in the slot core 4 having a C-shaped cross section. A so-called SZ type cable structure in which a plurality of slot grooves are provided in the longitudinal direction of the cable around a slot core having a circular cross section, or a so-called loose tube type cable structure in which a jelly is filled in the slot core. The present invention can also be applied to those.

  For example, in the SZ type optical fiber cable shown in FIG. 5, five slot grooves 3 having a U-shaped cross section are formed at equal intervals on the outer peripheral surface of the slot core 4 having a cylindrical cross section. A plurality of optical fibers 2 are stacked and arranged in each slot groove 3.

  In this SZ type optical fiber cable, as in the optical fiber cable of FIG. 1 described above, the sheath 6 has a multilayer structure in which the first sheath 6A and the second sheath 6B are formed from the inner side to the outer side of the cable, and a metal tape. 7 is divided into a first metal tape 7A and a second metal tape 7B that cover at least a half circumference of the slot core 4.

  The first metal tape 7A and the second metal tape 7B are arranged so as to be wound around the slot core 4 as a whole without being in contact with each other, and from the inside to the outside of the cable. The outer periphery of the slot core 4 is structured to cover the slot core 4 in the order of the first metal tape 7A, the first sheath 6A, the second metal tape 7B, and the second sheath 6B.

  In this SZ type optical fiber cable, a press-wound tape 20 such as a nonwoven fabric is provided so as to cover the outer peripheral surface of the slot core 4. The presser winding tape 20 is directly provided on the outer peripheral surface of the slot core 4.

  According to the SZ type optical fiber cable of FIG. 5 described above, when the sheaths 6A and 6B are peeled off in order, the metal tapes 7A and 7B are also formed in the same manner as the C slot type optical fiber cable having the structure shown in FIG. Since they are peeled off together, it is possible to provide an optical fiber cable structure in which the sheath stripping operation can be easily performed as compared with the case where the entire slot core 4 is covered with one metal tape 7. Further, in order to take out the optical fiber 2 from the slot groove 3 of this SZ type optical fiber cable, the optical fiber 2 can be taken out from the slot groove 3 by sequentially performing the sheath stripping process shown in FIG. . Since this sheath peeling process is the same as that of the previous embodiment, the description thereof is omitted. As a result, like the previous embodiment, the intermediate branching operation can be performed in a short time.

  The SZ-type optical fiber cable has a shape in which both the first metal tape 7A and the second metal tape 7B are continuously waved along the longitudinal direction of the cable, similar to the optical fiber cable of the previous embodiment. The first sheath 6A and the second sheath 6B are provided with markers M1 and M2 for longitudinally splitting each sheath with the cutter 11 along the cable longitudinal direction.

  In addition, even if the present invention is applied to an optical fiber cable having a one-way twisted slot structure in which the slot groove 3 is spiraled in the same direction along the length direction of the slot core 4, the same effects can be obtained. .

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical fiber cable in which a metal tape is wound around a sheath covering the slot core so as to be wound around the slot core.

DESCRIPTION OF SYMBOLS 1 ... Optical fiber cable 2 ... Optical fiber 3 ... Slot groove 4 ... Slot core 5 ... Opening (opening part of slot groove)
6 ... sheath 6A ... first sheath (sheath)
6B ... Second sheath (sheath)
6C ... Third sheath (sheath)
7 ... Metal tape 7A ... First metal tape (metal tape)
7B ... 2nd metal tape 7 (metal tape)
8 ... Tensile body 9 ... Pressing tape 10 ... Wave part 11 ... Cutter M1, M2, M2 ... Marker (marker indicating the cutting position)

Claims (6)

A slot core that stores and holds the optical fiber in the slot groove, a sheath that covers the entire slot core including the opening of the slot groove, and a metal tape vertically attached in the longitudinal direction of the cable in the sheath In optical fiber cable,
The sheath has a multi-layer structure including a first sheath, a second sheath, and a third sheath from the inside to the outside of the cable, and the metal tape includes a first metal tape that covers at least a half circumference of the slot core; A split structure with a second metal tape,
The first metal tape and the second metal tape are arranged so as to be wound around the slot core as a whole without being in contact with each other, and the first sheath and the first sheath are arranged from the inside to the outside of the cable. The slot core is covered in the order of a metal tape, a second sheath, a second metal tape, and a third sheath. The optical fiber cable according to claim 1,
Both said 1st metal tape and said 2nd metal tape are made into the shape which waves continuously along a cable longitudinal direction. The optical fiber cable characterized by the above-mentioned. The optical fiber cable according to claim 1 or 2,
An optical fiber cable, wherein a marker is provided on the first sheath, the second sheath, and the third sheath for longitudinally splitting each sheath with a cutter along a longitudinal direction of the cable. In the optical fiber taking-out method which takes out an optical fiber from the optical fiber cable according to claim 3,
A cutter is cut into the third sheath at a first position in the longitudinal direction of the optical fiber cable, the third sheath is cut into a ring along the circumferential direction of the cable, and then along the marker provided on the third sheath. Cutting the cutter into the third sheath to make a vertical tear, and further cutting the cutter into the third sheath again at the second position, which is the end position where the longitudinal tearing is performed, so that the third sheath is cut along the circumferential direction of the cable. And a third sheath stripping step of stripping the second metal tape together with the third sheath;
After cutting the cutter into the second sheath at the first position and cutting the second sheath along the circumferential direction of the cable, the cutter is cut into the second sheath along the marker provided on the second sheath. The first metal tape is cut together with the second sheath by cutting into a vertical tear and further cutting the cutter into the second sheath again at the second position and cutting the second sheath along the circumferential direction of the cable. A second sheath stripping step to strip;
After cutting the cutter into the first sheath at the first position and cutting the first sheath into a ring along the circumferential direction of the cable, the cutter is cut into the first sheath along the marker provided on the first sheath. The first sheath is peeled off by cutting the first sheath by cutting into the first sheath at the second position and cutting the first sheath into a ring along the circumferential direction of the cable. Taking process;
An optical fiber extraction method comprising: an optical fiber extraction step in which the slot groove is opened outward by peeling off the first sheath and the optical fiber is extracted from the slot groove. The optical fiber take-out method according to claim 4,
When the third sheath is torn in the third sheath stripping step, only the third sheath is torn with a cutter, and when the second sheath is torn in the second sheath stripping step, only the second sheath is cut with a cutter. An optical fiber extraction method characterized by cutting. A slot core that stores and holds the optical fiber in the slot groove, a sheath that covers the entire slot core including the opening of the slot groove, and a metal tape vertically attached in the longitudinal direction of the cable in the sheath In optical fiber cable,
A first metal tape and a second metal tape that have a multi-layer structure in which the sheath is a first sheath and a second sheath from the inner side to the outer side of the cable, and the metal tape covers at least a half circumference of the slot core. And a split structure
The first metal tape and the second metal tape are arranged so as to wrap around the slot core as a whole without coming into contact with each other, and the outer periphery of the slot core from the inside to the outside of the cable In addition, the slot core is covered in the order of a first metal tape, a first sheath, a second metal tape, and a second sheath.

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