JP2006251769A - Optical fiber cable and method and tool to take out optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable in which post-branching is available at the middle of a coated optical fiber along the longitudinal direction, and production of the cable is made at low cost. <P>SOLUTION: According to this invention, a inclusion member is arranged between a sheath and optical fibers along the longitudinal direction and in parallel so that the member is into contacts with them. Thus, when the sheath is to be divided, the optical fibers are not to be stuck to the sheath. As a result, the coated optical tape fibers are easily taken out without damaging the coated optical fibers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable in which an optical fiber (including a single optical fiber core or a plurality of optical fiber cores, an optical fiber unit, a tape-shaped optical fiber core, etc.) is housed in a sheath. In particular, the present invention relates to a wiring cable for branching an optical fiber core wire in the middle of the length of the cable and performing an intermediate drop.

In recent years, the construction of optical subscriber line networks has been progressing rapidly. Conventionally, an optical fiber cable 100 as shown in FIG. 15 is used as a wiring cable for connecting a trunk optical fiber cable and a drawing-in optical fiber cable for drawing into a home such as each home. In FIG. 15, reference numeral 3 is an optical fiber ribbon, 4 is a buffer, 5 is a tension member, 6 is a support wire, 7 is a sheath, and 8 is a sheath tear string. In this cable, the optical fiber tape core 3 is covered with a buffer 4 in a pipe-like sheath 7 so that the cable sheath can be removed in the middle of the length and the core can be taken out without fluctuation of optical loss. It has a housed structure.
Examples of such optical fiber cables include those disclosed in Patent Document 1 and Patent Document 2.

  On the other hand, an optical fiber cable 200 as shown in FIG. 16 is used as a small-core wiring cable. In FIG. 16, reference numeral 3 is an optical fiber ribbon, 5 is a tension member, 6 is a support wire, 7 is a sheath, and 9 is a notch for tearing the sheath.

Further, an optical fiber cable 300 as shown in FIG. 17 has been developed for the purpose of improving the take-out property of the optical fiber tape in the cable in which the optical fiber tape is laminated. In FIG. 17, reference numeral 3 is an optical fiber ribbon, 5 is a tension member, 7 is a sheath, and 9 is a notch for tearing the sheath.
An example of such an optical fiber cable is disclosed in Patent Document 3.
Japanese Patent Laid-Open No. 11-183764 JP 2000-131571 A JP 2004-117854 A

  The optical fiber cable 100 shown in FIG. 15 has an optical fiber tape 3 with a buffer 4 made of fibers so that optical loss fluctuations do not occur due to mechanical stress such as bending of the optical fiber core when the sheath is cut as described above. Although the core wire is protected and made independent of the sheath 7, since the buffer body 4 is provided, the outer diameter of the cable increases as a result, and the necessary support wire 6 becomes thicker. There was the fault that the material cost per core and the manufacturing cost were very high.

  On the other hand, the optical fiber cable 200 shown in FIG. 16 is lower in material cost and manufacturing cost than the cable shown in FIG. 15, but when the sheath 7 is divided by the notch 9 in the middle of the longitudinal direction, the optical fiber tape is applied to the sheath 7. Since the optical fiber tape core wire 3 is divided while being stuck, the optical fiber tape core wire 3 is bent, resulting in loss fluctuations. Therefore, there is a drawback that it is difficult to use as a wiring cable for intermediate post branching. Even when the optical fiber ribbon 3 is not attached to the sheath 7, the type shown in FIG. 15 uses a method of splitting the notch to the left and right to take out the conductor, and a general purpose tool (trade name: detacher) is used. In the method, there is a drawback that the core wire is easily bent due to the extra length of the sheath opened left and right, and loss fluctuation is added.

  In the optical fiber cable 300 shown in FIG. 17, when the sheath is cut at the notch, the sheath 7 is divided into four pieces, and the optical fiber ribbon 3 is taken out as compared with the optical fiber cable 200 shown in FIG. Although it is easy, in order to cut the sheath 7 to the vicinity of the optical fiber ribbon 3, a considerable force is still required, and the optical fiber ribbon 3 is bent, resulting in a loss variation. .

The optical fiber cables 200 and 300 shown in FIGS. 16 and 17 are called drop cables and indoor cables. Typically, the number of optical fibers to be accommodated is 1 to 12 cores, the tensile strength of the strength member is 2500 N or less, and from the utility pole. In order to be applied to a cable intended for wiring in a home and not intended for wiring without reinforcement between utility poles (small-core wiring cable), the branching property may be sufficient.
However, when it is intended for wiring without reinforcement between utility poles, typically when applied to a small-core wiring cable having a core number of 4 to 16 fibers and a tensile strength of 2500 N or more, Since the sheath of the small-core wiring cable tends to increase in size, there are cases where the branchability is not satisfactory.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical fiber cable that can branch an optical fiber core wire in the middle and can be manufactured at low cost.
In order to achieve the above object, an optical fiber cable according to claim 1 is an optical fiber cable having one or more optical fibers and a sheath covering the optical fiber, the optical fiber cable being interposed between the sheath and the optical fiber. An object is an optical fiber cable in which objects are arranged in parallel along the longitudinal direction of the optical fiber cable.
An optical fiber cable characterized in that a part or all of the inclusions are voids.

  The optical fiber cable according to claim 2 is an optical fiber cable characterized in that a part or all of the inclusions are voids.

  An optical fiber cable according to a third aspect is an optical fiber cable in which the inclusions are arranged on both sides of the optical fiber.

  The optical fiber cable according to claim 4 is arranged in a region where the long side length is different from the short side length, and the inclusions are arranged at least at both ends of the long side of the region. Fiber cable.

  In the optical fiber cable according to claim 5, when the shortest distance between the inclusion and the sheath surface is A and the shortest distance between the optical fiber and the sheath surface is B, A <B and 0.1 mm ≦ A ≦ An optical fiber cable having a length of 1.5 mm.

  The optical fiber cable according to claim 6 further includes a notch provided in the sheath, wherein the notch is formed toward the inclusion, and the tip of the notch wall surface of the notch on the optical fiber cable center side corresponds to the notch. An optical fiber cable characterized by being outside the center of an object.

  The optical fiber cable according to claim 7, wherein the optical fiber is formed by stacking optical fiber ribbons, the inclusions are disposed at both ends of the long side of the optical fiber, and in the cross section, between the inclusions The optical fiber cable is characterized in that a center line of the optical fiber is inclined at a predetermined angle with respect to a line connecting the center lines.

  An optical fiber cable according to an eighth aspect is the optical fiber cable, wherein the predetermined angle is not less than 5 degrees and not more than 60 degrees.

  The optical fiber cable according to claim 9 is an optical fiber cable characterized in that the inclusion is a string-like member not bonded to the sheath.

  An optical fiber cable according to a tenth aspect is an optical fiber cable in which a lubricant is applied to the optical fiber.

  An optical fiber cable according to an eleventh aspect of the present invention is an optical fiber cable characterized in that the number of optical fibers is 4 or more and 16 or less.

  An optical fiber cable according to a twelfth aspect includes a pair of tension members disposed in parallel with the optical fiber in the longitudinal direction in the sheath, and the portions of the sheath covering the optical fiber and the tension member are opposed to each other. An optical fiber having a substantially rectangular cross-section substantially parallel to a straight line connecting the centers of the pair of tension members, and the inclusion and the optical fiber arranged on a straight line connecting the pair of tension members It is a cable.

  An optical fiber cable according to a thirteenth aspect is an optical fiber cable, wherein the tension member has a tensile strength of 2500 N or more.

  The optical fiber extraction method according to claim 14, wherein the sheath is cut into a plurality of sheets by cutting the sheath from the outer surface of the sheath toward the inclusion, and the optical fiber is extracted from the divided sheath. It is a removal method.

  The optical fiber extraction tool according to claim 15 is an optical fiber extraction tool for an optical fiber cable, wherein the cutting blade is guided from the outer surface of the sheath toward the inclusion. .

In the optical fiber cable according to the first aspect, since the inclusions are arranged in parallel along the longitudinal direction so as to be in contact between the sheath and the optical fiber, the sheath is in contact with the inclusion of the optical fiber when the sheath is divided. Since the surface does not stick to the sheath, it is easy to take out the core wire, and it is possible to reduce fluctuations in light loss caused by bending while sticking to the divided sheath.
Further, since the sheath near the optical fiber is missing due to inclusions, it is not necessary to tear the sheath near the optical fiber, and the opportunity for the force required for tearing to reach the optical fiber can be reduced. Even when the blade is put into the sheath, the blade only needs to reach the inclusion as much as possible, so that the opportunity for the blade to reach the optical fiber can be reduced. Therefore, the core wire can be taken out safely.

Since one of the functions of the inclusion is to form a sheath defect near the optical fiber, the inclusion may be all or a part of the gap, for example, as in the optical fiber cable according to claim 2.
As the position of the inclusion, for example, as in the case of the optical fiber cable according to claim 3, when the inclusion is arranged on both sides of the optical fiber, the sheath is divided into two or more sheath pieces each containing the inclusion. The core wire can be easily taken out without sticking to the sheath piece.

  In this case, as in the optical fiber cable according to claim 4, the optical fiber is disposed in a region where the long side length is different from the short side length, and the inclusion is disposed at least at both ends of the long side of the region. In this case, the contact surface between the divided sheath piece and the optical fiber becomes almost a straight line, and the separation of the sheath piece and the optical fiber is easier.

  As in the case of the optical fiber cable according to claim 5, when A is the shortest distance between the inclusion and the sheath surface and B is the shortest distance between the optical fiber and the sheath surface, the inclusion from the sheath surface In addition to making a cut toward the surface, the optical fiber can be taken out by dividing the sheath by cutting the sheath along the surface of the sheath to expose the inclusions. In this case, the distance A is preferably set to a minimum so that inclusions are not exposed due to wear of the sheath or the like in normal use. For example, 0.1 mm ≦ A ≦ 1.5 mm is preferable.

  7. An optical fiber cable according to claim 6, further comprising a notch provided in a sheath, wherein the notch is formed toward an inclusion, and a front end portion of the notch wall surface of the notch on the optical fiber cable center side corresponds to the notch. When it is provided outside the center of the object, the blade is inserted along the notch, and when the blade tries to reach the inclusion, the blade slides on the inclusion and moves to the optical fiber side. It is possible to prevent the optical fiber from being damaged due to contact with the optical fiber.

  When using a type in which optical fiber tape cores are laminated as an optical fiber and providing inclusions at both ends of the long side of the optical fiber, for example, at the time of manufacturing, that is, when forming the sheath by extrusion coating, the pressure of the coating resin As a result, the optical fiber may be pushed by the inclusion. As described above, when the optical fiber is pushed by the inclusions, the optical fiber ribbons are separated from each other, and a gap is generated between the optical fiber ribbons. If this gap is large, there is a risk that water that has entered from the optical cable terminal will travel through the optical cable and adversely affect the connection portion of the opposite terminal. Therefore, as in the case of the optical fiber cable according to claim 7, when the center line of the optical fiber is inclined at a predetermined angle with respect to the line connecting the center lines of the inclusions in the cross section, the inclusion is caused by the inclination. Since the pushed force can be released in the tilt direction, it is possible to suppress the formation of a gap between the optical fiber ribbons.

  When the inclination is smaller than 5 degrees, the effect of escaping the force pushed by the inclusion is low, and it is not possible to suppress the occurrence of a gap between the tape core wires. Also, when the inclination is larger than 60 degrees, the optical fiber is greatly deviated from the straight line connecting the inclusions, so that it fits into the groove in the sheath, the optical fiber is not easily taken out, and a pair of tension members are used in combination. This is not preferable because the bending strain applied to the optical fiber when the optical fiber cable is bent in the direction perpendicular to the tension member arrangement direction increases, and the risk of the optical fiber breaking increases. Therefore, as in the case of the optical fiber cable according to the eighth aspect, the inclination is preferably 5 degrees or more and 60 degrees or less.

  In addition, as a kind of inclusion, for example, an optical fiber cable according to claim 9 is used as a cord-like member that does not adhere to the sheath, so that the sheath piece is separated from the surface where the cord-like member is in contact with the sheath. Dividing becomes easy, and the chance of bending the optical fiber excessively at the time of dividing the sheath and causing fluctuation in optical loss can be reduced.

  Furthermore, it is desirable that the optical fiber is coated with a lubricant so that the optical fiber can be easily peeled off from the divided sheath pieces.

As in the case of the optical fiber cable according to claim 11, in the case of, for example, a small-core wiring cable having 4 to 16 optical fibers, the sheath tends to be increased in size and strength, and the take-out property of the core is a problem. Therefore, it is more effective to apply the above-described configuration to these optical fiber cables.
For example, as described in claim 12, a small-core wiring cable typically includes a tension member and is configured to have a substantially rectangular sheath cross section. Therefore, the above-described configuration can be more effectively applied to such an optical fiber cable. Is. Support wires may be further added to these optical fiber cables.

  As described in claim 13, in a small-core cable intended for wiring between utility poles with a tensile strength of a tension member of an optical fiber cable of 2500 N or more, for example, without reinforcement, the sheath is increased in size and strength. Therefore, it is more effective to apply the above-described configuration to these optical fiber cables.

The above-described optical fiber cable is formed by cutting the sheath from the outer surface of the sheath toward the inclusion as described in claim 14 to divide the sheath into a plurality of pieces and take out the optical fiber from the divided sheath. And an optical fiber can be taken out easily. When cutting the sheath, the sheath may be torn or a blade may be put into the sheath. When there is a notch on the outer surface of the sheath on the inclusion, it is also preferable to tear the notch as a trigger or use the notch as a guide for the blade.

  In the above-described optical fiber cable, the optical fiber can be taken out more safely and easily by using a tool in which the cutting blade is guided from the outer surface of the sheath toward the inclusions.

  The best mode recognized by the inventors for carrying out the present invention will be described below. FIG. 1 is a cross-sectional view showing one embodiment of the cable of the present invention. The optical fiber cable 400 of FIG. 1 further covers the optical fiber core wire 2 coated with an ultraviolet curable resin to an outer diameter of 250 μm on a quartz fiber strand having a diameter of 125 μm with a tape coating material of an ultraviolet curable resin in a lump. Thus, a four-fiber optical fiber ribbon 3 having a width w = 1.1 mm and a thickness of 0.32 mm was constructed. Two optical fiber ribbons 3 were laminated to form an optical fiber unit 10.

  The inclusion 11 made of a PET string having a diameter of 0.5 mm was in close contact with the both ends of the long side of the optical fiber core unit 10 so as not to adhere. In addition, a steel wire tension member 5 having a diameter of 0.4 mm is arranged in a straight line with the optical fiber core unit 10 at a certain distance from the inclusions 11, and a steel wire having a diameter of 2.3 mm is disposed through the neck portion 12. The support wire 6 was covered with a polyethylene sheath 7.

  The section of the sheath 7 that covers the optical fiber core unit 10 and the tension member 5, that is, the cross-sectional shape of the cable main body is substantially rectangular. The long side of the cable body is parallel to the direction in which the optical fiber core unit 10 and the tension member 5 arranged in a straight line. In addition, four notches 9 are formed in the long side of the main body portion directly above the inclusions over the length of the cable. The cross-sectional shape of the cable main body has a long side dimension of 4 mm and a short side dimension of 3.3 mm. The optical fiber cable 400 is configured as a small-core wiring cable that is also intended to be wired between the utility poles without reinforcement. The tension member 5 has a tensile strength of 2500N and the support wire 6 has a tensile strength of 5000N.

  FIG. 2 is a perspective view of one embodiment of the tool of the present invention. This tool is composed of an upper member 13 and a lower member 14. When the sheath is torn, the optical fiber cable 1 is accommodated in the concave portion 15 of the lower member 14 and sandwiched between the upper member 13. Two or four cutting blades 16 for tearing the sheath 7 are attached to the upper member 13 and the lower member 14, respectively. The lateral position of the cutting blade 16 is adjusted to be directly above the inclusion inside the cable. The height of the cutting blade 16 is set to reach the inclusions 11.

  That is, the cutting blade 16 is guided from the outer surface of the sheath 7 toward the inclusion 11 by the concave portion 15. 3 and 4 are cross-sectional views showing the state in which this tool is sandwiched. FIG. 3 shows a case where there are two cutting blades 16, and FIG. 4 shows a case where there are four cutting blades 16. The sheath 7 is torn by pulling the optical fiber cable in the longitudinal direction with the tool sandwiched. When the main body portion of the cable of FIG. 1 is cut using this tool, the sheath 7 immediately above the inclusion is cut, and the sheath piece 17 is cut as shown in FIG. 5 for the tool of FIG. 3 and as shown in FIG. 6 for the tool of FIG. And the optical fiber ribbon 3 are divided.

  When the sheath 7 of the optical fiber cable 400 shown in FIG. 1 is cut with the tool of FIG. 3 or 4 and the optical fiber ribbon 3 is taken out, the optical fiber tape core is within 0.01 dB of the optical fiber loss fluctuation. Line 3 was removed. In addition, the characteristics of the steady optical fiber cable 400 were almost the same as those of a general optical fiber cable, and showed good characteristics.

  FIG. 7 shows another embodiment of the cable of the present invention. The optical fiber cable 1000 shown in FIG. 7 comprises an optical fiber core unit 10 formed by laminating eight optical fiber cores 2 coated with an ultraviolet curable resin so as to have an outer diameter of 500 μm on a quartz fiber strand having a diameter of 125 μm. did. The inclusion 11 made of a PET string having a diameter of 1.0 mm was closely attached but not adhered so as to be in contact with the end of the long side side office of the region where the optical fiber core unit 10 is accommodated. The other members are the same as in FIG. 1, but the cable body 18 gives an extra length to the support wire 6, and has a structure that allows the core wire to be easily pulled out even in a cable laying environment. It is said.

  Further, for the purpose of drum winding a cable with a surplus length, the cable main body has a larger outer diameter than the support wire and has a round shape. When the optical fiber cable 1000 was cut by using the tool shown in FIGS. 3 and 4 and the optical fiber core wire 2 was taken out, the core wire could be taken out within a loss fluctuation of 0.1 dB. Further, the characteristics of the stationary optical fiber cable 1000 were almost the same as those of a general optical fiber cable, and showed good characteristics.

As another example of the cable, the inclusion may be a string in which an arbitrary core material is coated with a UV resin, a nylon string, or the like. The cross-sectional shape may be an ellipse, a rectangle, or the like. The size of the inclusion can be selected as appropriate. The tension member may be FRP, fiber or the like. The optical fiber may be made of plastic as well as quartz. The number of optical fiber cores, the number of tape cores, and the number of laminated layers can be selected as appropriate. The lubricant applied to the optical fiber is optional such as talc or silicone oil. The sheath may not have a notch. The sheath having a rectangular cross section can be applied to the existing cable peripheral article as it is, and may be a circle, a shape, an ellipse, or the like. The material of the sheath 7 can be appropriately selected from polyvinyl chloride, polyethylene, non-halogen flame retardant polyethylene, and the like.
As an embodiment of the tool, the blade shape may be a fixed flat blade or a round blade that pushes the sheath while rotating, and the shape, dimensions, etc. other than the cable clamping portion can be arbitrarily set.

  FIG. 8 is a view showing another aspect of the optical fiber cable of the present invention. 7 is a sheath, 5 is a tension member, 9 is a notch, 11 is an inclusion, and 10 is an optical fiber unit. In this embodiment, a part of the inclusion is a portion where the sheath material is not included between the optical fiber units composed of a plurality of optical fiber single core wires, that is, the air gap A. A part of the disposed inclusions 11 is a gap A in contact with the optical fiber unit 10 (there is no coating resin for batch coating). That is, there is a portion where the coating resin is not inserted along the longitudinal direction of the optical fiber cable. By providing the gap A in which the coating resin is not inserted in this way, the take-out property of the core wire is improved at the time of branching in the middle of the optical fiber cable.

  The size of the gap A that does not contain the coating resin is not particularly limited, and the entire inclusion may be a gap, but the larger the part that does not contain the resin, the better the core takeout property, It is preferable that it is 1/2 or more of the short side of a cross section of an optical fiber unit.

  FIG. 9 is a diagram showing an optical fiber cable having a horizontally long or vertically long inclusion. FIG. 9A is a transverse cross-sectional view of an optical fiber cable having horizontally long inclusions on both sides of the optical fiber unit. FIG. 9B is a cross-sectional view of an optical fiber cable provided with vertically long inclusions on both sides of the optical fiber unit.

The size of the inclusion is not particularly limited, but when the size of the optical fiber cable is limited by a laying member or the like, and when it is desired to improve the take-out property of the core wire, FIG. As shown, it is also effective to arrange the inclusions vertically and make the length of the inclusions in the notch direction longer than the length in the direction of the tension members. If the size of the optical fiber cable is not limited, as shown in FIG. 9A, the inclusions are arranged horizontally, and the length of the inclusions in the direction toward the tension member is widened, so that a tool such as a nipper is used. The risk of damaging the optical fiber core wire can be further reduced.

  10 and 11 are diagrams for explaining an optical fiber cable in a case where the tape core wire is inclined and arranged. As shown in FIG. 10, when optical fiber tape cores are stacked as an optical fiber unit, the optical fiber tape cores are arranged at an angle α with respect to a line H connecting the center lines of inclusions. . This is because even when the inclusion pushes the optical fiber unit (tape laminate) due to the pressure of the coating resin during the extrusion production of the optical cable, the tape cores are inclined and no gap is generated between the tape cores. The inclination angle α is not less than 5 degrees and less than 60 degrees.

  As shown in FIG. 11, when the inclination α is small, less than 5 degrees, the tape core laminate is pushed by inclusions, and a gap is generated between the optical fiber ribbons. Also, if the inclination is larger than 60 degrees, the optical fiber tape core wire is likely to be enveloped, the core wire takeout property is inferior, and the optical fiber cable is bent perpendicularly to the tension member alignment direction. Since the bending strain applied to the fiber increases, the risk of breaking the optical fiber increases, which is not preferable.

In the following, the influence of the tilt angle was examined by Examples.
With respect to the optical fiber cable having a cross-sectional structure as shown in FIG. 10, several types of inclusions having an inclusion size of φ0.8 mm and varying the arrangement angle (α) of the tape core wire were manufactured, and a water running test was performed. In the water running test, as shown in FIG. 12, a tube filled with water at a height of 1 m was installed at the cable end, and it was confirmed whether water could be transmitted to the opposite end of the optical cable having a length of 40 m after 240 hours. The case where water was not confirmed at the opposite terminal was regarded as acceptable (◯), and the case where water was confirmed at the opposite terminal was regarded as unacceptable (×). For the core take-out property, the core take-out tool according to the present invention is used, and when the loss fluctuation at the time of taking out the core wire is 1 dB or less, it is accepted (◯), and the one that causes the loss fluctuation larger than that is rejected (× ). The measurement conditions were a wavelength of 1550 nm and a sampling time of 1 msec.

表から明らかなように、テープ心線の傾き角度が本発明の範囲を超えて７０度と大きい場合には、心線取り出し性が劣化していることがわかる。また、テープ心線の傾き角度が本発明の範囲外の２度と小さい場合には、水走り試験が劣っており、光ファイバ心線間に間隙が発生していることがわかる。 The results are shown in the table.
table

As is apparent from the table, when the inclination angle of the tape core wire is as large as 70 degrees beyond the range of the present invention, it can be seen that the core wire take-out property is deteriorated. In addition, when the inclination angle of the tape core wire is as small as 2 degrees outside the range of the present invention, the water running test is inferior, and it can be seen that a gap is generated between the optical fiber core wires.

  FIG. 13 is a diagram illustrating the positional relationship between inclusions and notches. As shown in FIG. 13, inclusions 11 are arranged on both sides of an optical fiber unit 3 in which optical fiber ribbons are laminated. When the tool blade is inserted toward the inclusion 11, the position of the inclusion and the notch where the blade does not affect the optical fiber core wire is the position of the inclusion corresponding to the tip of the notch wall surface on the optical fiber cable center side. It is defined to be outside the center. That is, as shown in FIG. 13, the line passing through the tip of the notch wall surface is located outside the center line of the inclusion. When the tool blade is inserted, since the blade enters outside the center of the inclusion, the blade does not touch the optical fiber core wire directly. Therefore, the optical fiber core wire can be reliably prevented from being damaged by the tool blade. The same is true for the other inclusions and notch positions of the optical fiber cable.

  FIG. 14 is a diagram illustrating an optical fiber cable that does not include a notch. In this aspect, the inclusions are provided on both sides of the optical fiber unit made of the optical fiber core wire. The optical fiber unit does not have a notch. In an optical fiber cable not provided with a notch, the distance from the surface of the optical fiber cable that is collectively covered to the inclusion is smaller than the distance from the surface of the optical fiber cable to the optical fiber unit.

  In this way, by defining the distance from the surface of the optical fiber cable to the inclusion and the distance from the surface of the optical fiber cable to the optical fiber unit, a tool having a separating blade or the like toward the position of the inclusion is used. Or by cutting the upper and lower surfaces of the optical fiber cable, the optical fiber cable can be divided, and the optical fiber core can be taken out from the middle of the optical fiber cable without causing a serious bending or the like in the core. .

Sectional drawing which shows one Example of the optical cable of this invention. The perspective view which shows one Example of the optical fiber extraction tool of this invention. The principal part sectional drawing of the optical fiber extraction tool in one Example of this invention. Sectional drawing of the principal part of the optical fiber extraction tool in the other Example of this invention. The end view which shows the optical cable of the state cut | disconnected by the optical fiber extraction tool shown in FIG. The end view which shows the optical cable of the state cut | disconnected by the optical fiber extraction tool shown in FIG. The end view of the optical cable which shows the other Example of this invention. FIG. 8 is a view showing another aspect of the optical fiber cable of the present invention. FIG. 9 is a diagram showing an optical fiber cable having a horizontally long or vertically long inclusion. FIG. 10 is a diagram for explaining an optical fiber cable when the tape core wire is inclined. FIG. 11 is a diagram for explaining an optical fiber cable when the tape core wire is disposed at an inclination. FIG. 12 is a diagram for explaining a water running test. FIG. 13 is a diagram illustrating the positional relationship between inclusions and notches. FIG. 14 is a diagram illustrating an optical fiber cable that does not include a notch. The end view which shows an example of the conventional optical fiber cable. The end view which shows the other example of the conventional optical fiber cable. The end elevation which shows the other example of the conventional optical fiber cable.

Explanation of symbols

100, 200, 300, 400, 1000 Optical fiber cable 2 Optical fiber core wire 3 Optical fiber tape core wire 4 Buffer 5 Tension member 6 Support wire 7 Sheath 8 Tear string 9 Notch 10 Optical fiber core unit 11 Inclusion 12 Neck 13 Upper member 14 Lower member 15 Recess material 16 Scratching blade 17 Sheath piece 18 Cable body

Claims (15)

  An optical fiber cable having one or more optical fibers and a sheath covering the optical fiber, wherein an inclusion is disposed in parallel along the longitudinal direction of the optical fiber cable between the sheath and the optical fiber. An optical fiber cable characterized by The optical fiber cable according to claim 1, wherein a part or all of the inclusion is a gap.   The optical fiber cable according to claim 1, wherein the inclusion is disposed on both sides of the optical fiber.   The said optical fiber is arrange | positioned in the area | region where the long side side length differs from the short side length, and the said inclusion is arrange | positioned at the long side side both ends of the said area | region at least. Fiber optic cable.   A <B and 0.1 mm ≦ A ≦ 1.5 mm, where A is the shortest distance between the inclusion and the sheath surface, and B is the shortest distance between the optical fiber and the sheath surface. The optical fiber cable according to any one of claims 1 to 4. A notch provided in the sheath, wherein the notch is formed toward the inclusion, and a tip portion of the notch wall surface of the notch on the optical fiber cable center side is outside the center of the corresponding inclusion. The optical fiber cable according to any one of claims 1 to 5, characterized in that   The optical fiber is formed by laminating optical fiber ribbons, the inclusions are disposed at both ends of the long side of the optical fiber, and the optical fiber is connected to a line connecting the center lines of the inclusions in a cross section. The optical fiber cable according to any one of claims 1 to 6, wherein a center line of the fiber is inclined at a predetermined angle.   The optical fiber cable according to claim 7, wherein the predetermined angle is not less than 5 degrees and not more than 60 degrees.   9. The optical fiber cable according to claim 1, wherein the inclusion is a string-like member that is not bonded to the sheath.   The optical fiber cable according to any one of claims 1 to 9, wherein the optical fiber is coated with a lubricant.   The optical fiber cable according to any one of claims 1 to 10, wherein the optical fiber has 4 or more and 16 or less cores.   The optical fiber cable according to any one of claims 1 to 6, further comprising: a pair of tension members disposed in parallel with the optical fiber in a longitudinal direction in the sheath, and the optical fiber of the sheath The portion covering the tension member has a substantially rectangular cross section whose two opposite sides are substantially parallel to a straight line connecting the centers of the pair of tension members, and the inclusion and the optical fiber are on a straight line connecting the pair of tension members. An optical fiber cable characterized by being arranged.   The optical fiber cable according to claim 12, wherein the tension member has a tensile strength of 2500 N or more.   14. The optical fiber extraction method for an optical fiber cable according to claim 1, wherein the sheath is divided into a plurality of pieces by cutting the sheath from the outer surface of the sheath toward the inclusion. An optical fiber extraction method characterized in that an optical fiber is extracted from a sheath.   14. An optical fiber extraction tool for an optical fiber cable according to claim 1, wherein a cutting blade is guided from the outer surface of the sheath toward the inclusion.

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