JP6059592B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to an optical fiber cable that facilitates an intermediate post-branching operation.

  In an optical fiber cable, a structure in which a tear string is embedded in the cable is known in order to enable intermediate rear branching (see, for example, Patent Document 1).

In addition, a structure is known in which tension members are arranged in parallel on both sides of the optical fiber core and synthetic resin release tapes are arranged in parallel above and below the optical fiber core (see, for example, Patent Document 2).
Further, a structure is known in which an optical fiber core wire is accommodated in a gap provided in a coated resin body via a fiber inclusion (see, for example, Patent Document 3).
Further, a structure in which a notch is formed on a side surface on the long side of a rectangular sheath that accommodates an optical fiber core wire is known (see, for example, Patent Document 4).

JP 2012-220506 A JP 2008-070601 A JP 2004-361475 A JP 2012-053107 A

  However, in the optical fiber cable described in Patent Document 1, in order to take out the tear string, it is necessary to cut the cable jacket with a tool such as a knife, and the workability is poor. In addition, if the operator is not skilled, when cutting the cable jacket, the blade of the tool may reach the cable core and the internal optical fiber may be damaged.

  In addition, in the optical fiber cable described in Patent Document 2 or 3, it is necessary to use a fibrous material, a synthetic resin film material, or the like in order to ensure intermediate post-branching. For this reason, while raising the cost at the time of manufacture, control of the dimension and position of those materials itself is difficult, and manufacturing difficulty is high.

  Further, in the optical fiber cable described in Patent Document 4, although a fibrous material, a synthetic resin film, or the like is not used, it is necessary to form a precise space inside the cable covering. The control is very difficult, and a special device is required to secure the internal space state in the cable longitudinal direction, which also increases the manufacturing cost.

  Further, in the optical fiber cables described in Patent Documents 2 to 4, since the blade of the tool is inserted to the vicinity of the optical fiber, it is necessary to adjust the blade with high accuracy, and an expensive tool is required.

  In view of the above problems, an object of the present invention is to provide an optical fiber cable that can be easily taken out from the inside without damaging the optical fiber.

  According to one aspect of the present invention, an optical fiber, a pair of tensile members disposed in parallel with the optical fiber with the optical fiber interposed therebetween, a pair of coating layers respectively covering the pair of tensile members, the optical fiber, and the pair And an outer cover that collectively coats the coating layers, the optical fiber is disposed at a position sandwiched between a pair of planes including the tops of the pair of coating layers, and is an area sandwiched between the pair of planes. The outer jacket is divided at the periphery, and the outer jacket is not fused or bonded to the pair of coating layers from the top of the pair of coating layers to the side surface on the optical fiber side, and the top of the pair of coating layers An optical fiber cable is provided which is fused or bonded to a pair of coating layers on the side farther from the optical fiber.

  In one embodiment of the present invention, the outer cover may wrap around in a region sandwiched between a pair of planes.

  In one embodiment of the present invention, the tops of the pair of coating layers may form a line in a cross section perpendicular to the cable longitudinal direction.

  In one embodiment of the present invention, a protrusion for fusing or bonding to the jacket may be provided on the side farther from the optical fiber than the tops of the pair of coating layers.

  In one aspect of the present invention, the apparatus further includes a support line portion disposed on a plane including a pair of strength members, and a connection portion that connects the outer cover and the support line portion, and the protrusion is directly below the connection portion. You may arrange | position in a different position.

  In one embodiment of the present invention, an even number of protrusions may be arranged in plane symmetry on a plane including a pair of strength members.

  In one embodiment of the present invention, an adhesive resin layer for fusing or adhering to the jacket may be provided on the side farther from the optical fiber than the tops of the pair of coating layers.

  In one embodiment of the present invention, the hardness of the coating layer may be higher than the hardness of the jacket.

  In one embodiment of the present invention, a plurality of optical fibers may be mounted, the plurality of optical fibers may be unitized with a plus-chip film, tape, or thread, and a plastic film, tape, thread, or the like may be disposed as an inclusion. .

  In one embodiment of the present invention, a color band or a printing layer may be provided on the surface of the outer cover at a position corresponding to the tops of the pair of coating layers.

  In one embodiment of the present invention, a groove portion may be formed in a jacket positioned above the optical fiber in parallel with the optical fiber.

  ADVANTAGE OF THE INVENTION According to this invention, the optical fiber cable which can be taken out easily from the inside, without damaging an optical fiber can be provided.

It is sectional drawing which shows an example of the optical fiber cable which concerns on the 1st Embodiment of this invention. FIGS. 2A to 2C are cross-sectional views for explaining an example of an intermediate post-branching method for the optical fiber cable according to the first embodiment of the present invention. 3A and 3B are cross-sectional views for explaining another example of the intermediate post-branching method for the optical fiber cable according to the first embodiment of the present invention. It is sectional drawing for demonstrating the case where it cuts into the jacket of the optical fiber cable which concerns on a comparative example. It is sectional drawing for demonstrating the case where it cuts into the jacket of the optical fiber cable which concerns on the 1st Embodiment of this invention. It is sectional drawing for demonstrating the case where the stress of a diagonal direction or a horizontal direction is provided to the optical fiber cable which concerns on the 1st Embodiment of this invention. FIG. 7A to FIG. 7E are cross-sectional views showing examples of optical fiber cables according to the first modification of the first embodiment of the present invention. FIGS. 8A and 8B are cross-sectional views showing examples of the optical fiber cable according to the second modification of the first embodiment of the present invention. FIG. 9A and FIG. 9B are cross-sectional views respectively showing still another example of the optical fiber cable according to the second modification of the first embodiment of the present invention. It is sectional drawing which shows an example of the optical fiber cable which concerns on the 3rd modification of the 1st Embodiment of this invention. FIGS. 11A and 11B are cross-sectional views showing examples of optical fiber cables according to a fourth modification of the first embodiment of the present invention. It is sectional drawing which shows an example of the optical fiber cable which concerns on the 5th modification of the 1st Embodiment of this invention. It is sectional drawing which shows an example of the optical fiber cable which concerns on the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the case where the neck part of an example of the optical fiber cable which concerns on the 2nd Embodiment of this invention is cut | disconnected. It is sectional drawing for demonstrating the case where the neck part of the other example of the optical fiber cable which concerns on the 2nd Embodiment of this invention is cut | disconnected. It is sectional drawing which shows an example of the optical fiber cable which concerns on the modification of the 2nd Embodiment of this invention. It is sectional drawing which shows another example of the optical fiber cable which concerns on the modification of the 2nd Embodiment of this invention. It is sectional drawing which shows an example of the optical fiber cable which concerns on other embodiment of this invention. It is sectional drawing which shows another example of the optical fiber cable which concerns on other embodiment of this invention. It is sectional drawing which shows another example of the optical fiber cable which concerns on other embodiment of this invention.

  Next, first and second embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings. The first and second embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention. The technical idea of the present invention The material, shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
As shown in FIG. 1, the optical fiber cable according to the first embodiment of the present invention is arranged in parallel with the cable core 10 having at least one optical fiber and the cable core 10 with the cable core 10 interposed therebetween. The pair of strength members 11a and 11b, the pair of coating layers 12a and 12b that respectively cover the pair of strength members 11a and 11b, and the jacket 13 that collectively covers the periphery of the cable core 10 and the pair of coating layers 12a and 12b. With.

  The cable core 10 is between a plane S1 that includes the top portions 14a and 14b that are the upper surfaces of the pair of coating layers 12a and 12b, and a plane S2 that includes the top portions 15a and 15b that are the lower surfaces of the pair of coating layers 12a and 12b. It is arranged to be sandwiched between. In the cross section perpendicular to the cable longitudinal direction, each of the top portions 14a, 14b, 15a, and 15b forms a line.

  The cable core 10 houses at least one optical fiber in a cylindrical space. In the first embodiment of the present invention, the number of optical fibers and the types of optical fibers are not particularly limited. For example, a collection of 24 optical fiber cores having a diameter of 0.25 mm is used. As the optical fiber, a core wire such as an optical fiber strand, an optical fiber core wire, or an optical fiber tape core wire can be adopted. Among these, as the optical fiber ribbon, an intermittently fixed ribbon or the like can be used. Further, when having a plurality of optical fibers, they may be stretched in parallel without being twisted in the longitudinal direction, may be twisted in one direction, may be twisted in an SZ shape, and may be twisted in one direction. You may hold | maintain the composite shape which SZ twist changes in the middle. Further, a plurality of optical fiber units on which a plurality of optical fibers are mounted may be mounted in the jacket 13. These items can be appropriately determined according to transmission characteristics required by the system, the number of necessary optical fibers, and the like.

  As a material for the covering layers 12a and 12b and the jacket 13, a resin such as polyvinyl chloride (PVC), polyethylene (PE), nylon (registered trademark), ethylene fluoride or polypropylene (PP) can be used. The same material may be used as the covering layers 12a and 12b and the jacket 13, and different materials may be used.

  Here, it is preferable that the hardness of the coating layers 12 a and 12 b is higher than the hardness of the outer cover 13. For example, PVC can be used as the outer cover 13, and PP can be used as the covering layers 12a and 12b. By making the hardness of the covering layers 12a and 12b higher than the hardness of the jacket 13, when making a cut in the jacket 13, it is confirmed whether the cut has been made at an appropriate position by the reaction force when the blade is inserted. Can do.

  The jacket 13 is a region sandwiched between the planes S1 and S2 and wraps around the pair of coating layers 12a and 12b. For this reason, the thickness 13 of the jacket 13 at the position corresponding to the cable core 10 is thicker than the thickness T1 at the position corresponding to the top portions 14a and 14b of the pair of coating layers 12a and 12b. Further, in the region sandwiched between the planes S1 and S2 and the side surfaces 16a and 16b on the optical fiber side of the pair of coating layers 12a and 12b, the jacket 13 is divided with the cable core 10 interposed therebetween.

  The jacket 13 is not fused or bonded to the pair of coating layers 12a, 12b from the top portions 14a, 14b, 15a, 15b of the pair of coating layers 12a, 12b to the side surfaces 16a, 16b on the optical fiber side. The coating layers 12a and 12b are fused or bonded to the pair of coating layers 12a and 12b on the side surfaces 17a and 17b outside the top portions 14a, 14b, 15a and 15b. In the embodiment of the present invention, “fusion” means that the coating layers 12a and 12b and the outer jacket 13 are fused by heat at the time of extrusion molding, and “adhesion” means at the time of extrusion molding. It means that it is bonded by a method different from the fusion by heat.

  The strength members 11a and 11b are made of a metal wire such as a steel wire or fiber reinforced plastic (FRP). The shape of the strength members 11a and 11b is not limited to a linear body, and may be a belt-like body. The band-like body is a long band-like one having a flat cross section, an elliptical shape, or a rectangular shape such as a rectangle.

  When branching the optical fiber cable according to the first embodiment of the present invention after intermediate, as shown in FIG. 2A, a tool having blades 21a and 21b is used to form the coating layers 12a and 12b. Cuts are made in the jacket 13 located at the tops 14a, 14b. The lengths of the blades 21a and 21b are adjusted to be longer than the length reaching from the surface of the jacket 13 to the top portions 14a and 14b of the coating layers 12a and 12b and not reaching the cable core 10 from the surface of the jacket 13. It ’s fine. The position to be cut may be any position of the top portions 14a and 14b of the coating layers 12a and 12b. Thereby, as shown in FIG.2 (b), a part of the jacket 13 above the cable core 10 can be easily removed. And as shown in FIG.2 (c), the optical fiber contained in the cable core 10 can be taken out easily from the inside.

  In addition, as shown to Fig.3 (a), four places of the jacket 13 located in the top parts 14a, 14b, 15a, 15b of the coating layers 12a, 12b using the tool which has the blades 21a, 21b, 22a, 22b A notch may be made in the outer cover 13 and divided into four as shown in FIG. At this time, since the pair of coating layers 12a, 12b and the jacket 13 are fused or bonded on the side surfaces 17a, 17b outside the top portions 14a, 14b, 15a, 15b of the pair of coating layers 12a, 12b, Even after the division, the coating layers 12a, 12b and a part of the outer jacket 13 are integrated.

  In the first embodiment of the present invention, the top portions 14a, 14b, 15a, 15b form a line by making the cross-sectional shape of the covering layers 12a, 12b substantially rectangular, and the cuts are made within the range. Just put it in. Therefore, it is not necessary to excessively increase the alignment accuracy of the tool blades 21a, 21b, 22a, and 22b as compared with the case where the covering layers 12a and 12b have a circular cross-sectional shape, and the operation can be easily performed.

  In FIG. 4, as a comparative example, the cable core 110 is arranged so as to reach a plane including the tops of the pair of covering layers 112 a and 112 b covering the pair of tensile members 111 a and 111 b or outside (upward) from the plane. Shows the structure. In this case, when the cut is made in the jacket 113, the optical fiber included in the cable core 110 may be damaged if the cut is accidentally made in the jacket 113 above the optical fiber instead of the appropriate position indicated by the dotted line. . On the other hand, according to the optical fiber cable which concerns on the 1st Embodiment of this invention, the cable core 10 is arrange | positioned inside plane S1 containing top part 14a, 14b. For this reason, as shown in FIG. 5, even when the outer cover 13 above the cable core 10 is cut, the tool blades 21 a and 21 b do not reach the cable core 10, so that the optical fibers included in the cable core 10 Damage can be prevented.

  In addition, according to the optical fiber cable according to the first embodiment of the present invention, since a synthetic resin film or fiber for securing the intermediate post-branching property is not used, compared with the case where these are used. Excellent productivity.

  Further, if the covering layers 12a and 12b and the jacket 13 are not fused or bonded, the cable 13 is divided when the jacket 13 is divided as shown in FIGS. 3 (a) and 3 (b). The structure excluding the core 10 is divided into six. For this reason, operations such as intermediate post-branching are troublesome, and there is a possibility that the optical fiber is accidentally cut during the removal and cutting of unnecessary resin. On the other hand, according to the optical fiber cable according to the first embodiment of the present invention, the outer side surfaces 17a, 17b of the coating layers 12a, 12b and the jacket 13 are fused or bonded, As shown in FIGS. 3A and 3B, the number of structures when the outer cover 13 is divided can be reduced to four, and workability can be improved.

  Also, if the covering layers 12a and 12b and the jacket 13 are not fused or bonded, the equivalent linear expansion coefficient between the coating layers 12a and 12b and the jacket 13 when the cable is subjected to temperature expansion and contraction. Due to the difference, the tensile strength members 11a and 11b may protrude and retract. On the other hand, according to the optical fiber cable according to the first embodiment of the present invention, the outer side surfaces 17a, 17b of the coating layers 12a, 12b and the jacket 13 are fused or bonded, Even when temperature expansion and contraction is applied, the tensile strength members 11a and 11b can be prevented from protruding and retracting.

  In addition, if the covering layers 12a and 12b and the jacket 13 are not fused or bonded, and the cable is divided by hand without using a tool when the cable is opened, the jacket 13 is torn. A notch is required as a stress concentration point. In order to form the notch, it is necessary to provide a resin for forming the notch in a shape after securing the minimum thickness for ensuring the mechanical strength at the lowermost part of the notch. As a result, the basis weight of the material to be used is increased, which is disadvantageous in terms of cost, and the outer diameter and dimensions of the cable are increased. On the other hand, according to the optical fiber cable according to the first embodiment of the present invention, the outer side surfaces 17a, 17b of the coating layers 12a, 12b and the jacket 13 are fused or bonded, When tearing out the outer cover 13, stress is applied to the interfaces I 1, I 2, I 3, and I 4 between the outer side of the coating layers 12 a and 12 b and the outer cover 13 and the non-bonded or non-adhered part. Concentrate. For this reason, even if it does not provide a notch in the outer jacket 13, the outer jacket 13 can be torn and struck out.

  Further, if the covering layers 12a and 12b and the jacket 13 are not fused or bonded, the strength is reduced with respect to stress such as side pressure and impact, and the mechanical characteristics of the cable are deteriorated. On the other hand, according to the optical fiber cable according to the first embodiment of the present invention, the outer side surfaces 17a, 17b of the coating layers 12a, 12b and the jacket 13 are fused or bonded, The mechanical properties of the cable can be improved.

  Further, since the outer cover 13 is a region sandwiched between the planes S1 and S2 and wraps around the inner sides of the coating layers 12a and 12b, the outer cover 13 is subjected to the stresses F1 and F2 in the oblique direction and the lateral direction as shown in FIG. Mechanical strength can be improved.

  The optical fiber cable according to the first embodiment of the present invention, for example, covers the periphery of the pair of strength members 11a and 11b with a pair of coating layers 12a and 12b by extrusion molding, and then is parallel to the optical fiber. Then, it can be manufactured by forming the outer cover 13 by covering them with resin together by extrusion molding.

(First modification)
In the optical fiber cable according to the first embodiment of the present invention, the case where the cross-sectional shape perpendicular to the cable longitudinal direction of the covering layers 12a and 12b is substantially rectangular has been described, but the cross-sectional shapes of the covering layers 12a and 12b are The shape is not particularly limited, and various shapes can be employed.

  For example, as shown to Fig.7 (a), the cross-sectional shape of coating layer 12a, 12b may be circular. In FIG. 7A, the top portions 18a and 18b of the covering layers 12a and 12b are dotted. At the time of intermediate post branching in the structure shown in FIG. 7A, a tool having a blade with a length reaching from the outer cover 13 to the top portions 18a and 18b of the covering layers 12a and 12b may be used. In addition, the length of the blade of a tool should just be more than the length which reaches from the jacket 13 to the top parts 18a and 18b of the coating layers 12a and 12b, and shorter than the length which reaches from the jacket 13 to the cable core 10.

  Moreover, as shown in FIG.7 (b), the cross-sectional shape of coating layer 12a, 12b may be the shape which made the upper part and the lower part of a circle flat.

  Moreover, as shown in FIG.7 (c), the cross-sectional shape of coating layer 12a, 12b may be a pentagon which has a vertex inside.

  Moreover, as shown in FIG.7 (d), the cross-sectional shape of coating layer 12a, 12b may be a pentagon which has a vertex on the outer side.

  Moreover, as shown in FIG.7 (e), the cross-sectional shape of coating layer 12a, 12b may be the shape which surrounds the cable core 10. As shown in FIG. According to the structure shown in FIG. 7E, it is possible to suppress the resin forming the jacket 13 from reaching the interfaces 23 a and 23 b between the coating layers 12 a and 12 b and the cable core 10.

  According to the first modification of the first embodiment of the present invention, various shapes can be adopted as the cross-sectional shapes of the coating layers 12a and 12b.

(Second modification)
As shown in FIG. 8A, the optical fiber cable according to the second modification of the first embodiment of the present invention has three protrusions 31a to 31c and 32a to the outside of the covering layers 12a and 12b. The point where 32c is provided is different from the first embodiment of the present invention.

  The protrusions 31a to 31c and 32a to 32c may be continuous in parallel with the cable core 10 in the cable longitudinal direction, or may be provided intermittently (intermittently). In addition, the cross-sectional shape of protrusion 31a-31c, 32a-32c is not specifically limited, A curved surface may be sufficient and a triangle may be sufficient. Further, the number (number) of the protrusions 31a to 31c and 32a to 32c is not particularly limited. Further, the protrusions 31a to 31c and 32a to 32c may melt and disappear during the extrusion molding of the coating layers 12a and 12b, or may remain and maintain their shapes.

  Further, in place of the protrusions 31a to 31c and 32a to 32c, as shown in FIG. 8B, a non-adhesive resin is used as a material for the coating layers 12a and 12b, and it is bonded to the outside of the coating layers 12a and 12b. Resin layers 33a and 33b may be provided.

  According to the second modification of the first embodiment of the present invention, by using the protrusions 31a to 31c and 32a to 32c and the adhesive resin layers 33a and 33b, the outer side and the outer cover of the covering layers 12a and 12b are used. 13 can be firmly bonded or fused.

  As shown in FIG. 9A, even when the cross-sectional shapes of the covering layers 12a and 12b are circular, by providing the protrusions 31a to 31c and 32a to 32c outside the covering layers 12a and 12b, the covering layer 12a , 12b can be fused to the jacket 13.

  Further, instead of the protrusions 31a to 31c and 32a to 32c, as shown in FIG. 9B, adhesive resin layers 33a and 33b may be provided outside the coating layers 12a and 12b made of non-adhesive resin. .

(Third Modification)
As shown in FIG. 10, the optical fiber cable according to the third modification of the first embodiment of the present invention covers a plurality of optical fibers by covering the periphery of the cable core 10 with a presser winding (plastic film) 34. Is different from the first embodiment of the present invention in that they are integrated (unitized) into an optical fiber unit. Instead of covering the periphery of the plurality of optical fibers with the plastic film 34, the bunching may be spirally formed with a thread or a tape.

  As a material for the plastic film 34, the thread or the tape, a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or epoxy is used. A thermosetting resin can be used.

  When mounting a plurality of optical fibers, if the plurality of optical fibers are not integrated, the optical fiber remains inside the cable when trying to take out the optical fiber as shown in FIG. 2 (c). In some cases, it is difficult to take out the remaining optical fiber, resulting in a decrease in workability. In addition, when the jacket 13 is divided into four as shown in FIG. 3B, the divided structure and a plurality of optical fibers are separated, and access to an arbitrary optical fiber may be complicated. is there. On the other hand, according to the third modification of the first embodiment of the present invention, when a plurality of optical fibers are mounted inside, the optical fibers are covered with a plastic film 34, or a thread or tape. By bunching with, for example, the optical fiber can be integrated. As a result, the optical fiber can be easily taken out, the optical fiber can be prevented from being separated, and workability can be improved.

(Fourth modification)
In the optical fiber cable according to the fourth modification of the first embodiment of the present invention, as shown in FIG. 11A, color bands 35a, 35b, 36a, 36b are formed on the surface of the jacket 13. This is different from the first embodiment of the present invention. The color bands 35a, 35b, 36a, 36b can be formed by extruding together with the outer cover 13.

  Further, instead of forming the color bands 35a, 35b, 36a, 36b on the surface of the outer cover 13, as shown in FIG. 11B, printed layers 37a, 37b, 38a, 38b are formed on the surface of the outer cover 13. May be. The print layers 37a, 37b, 38a, and 38b can be formed by inkjet printing or the like.

  Further, in place of forming the color bands 35a, 35b, 36a, 36b and the printing layers 37a, 37b, 38a, 38b on the surface of the jacket 13, although not shown, notches are formed on the surface of the jacket 13. May be.

  According to the fourth modification of the first embodiment of the present invention, the color bands 35a, 35b, 36a, 36b, the printing layers 37a, 37b, 38a, 38b, or notches are formed on the surface of the outer cover 13. This makes it possible to recognize the location where the cut is made from the appearance and further improve the workability.

(Fifth modification)
As shown in FIG. 12, the optical fiber cable according to the fifth modification of the first embodiment of the present invention has recesses (grooves) 39a and 39b in which the jacket 13 located above the cable core 10 is thinned. Is different from the first embodiment of the present invention.

  The groove portions 39a and 39b extend parallel to the cable core 10 in the cable longitudinal direction. The thickness of the groove portions 39a and 39b of the jacket 13 may be thicker, thinner or the same as the thickness of the jacket 13 on the coating layers 12a and 12b.

  According to the fifth modification of the first embodiment of the present invention, the groove 39a, 39b is provided on the surface of the outer jacket 13 located above the cable core 10, thereby reducing the contact area during wiring. be able to. As a result, the friction coefficient can be reduced, and the lineability can be improved.

(Second Embodiment)
A self-supporting optical fiber cable will be described as an optical fiber cable according to the second embodiment of the present invention.

  As shown in FIG. 13, the optical fiber cable according to the second embodiment of the present invention includes a support wire portion (hanging wire portion) 2, a cable main body portion 1, a support wire portion 2, and a cable main body portion 1. A neck portion 3 connected in the major axis direction of the cable body portion 1 is provided.

  The cable body 1 includes an optical fiber 40, a pair of strength members 41a and 41b arranged in parallel to the optical fiber 40 with the optical fiber 40 interposed therebetween, and a pair of coating layers 42a and 42b that cover the strength members 41a and 41b. And a jacket 43 that collectively covers the optical fiber 40 and the pair of coating layers 42a and 42b.

  It is sandwiched between a plane S3 that includes the top portions 46a and 46b that are the upper surfaces of the pair of coating layers 42a and 42b, and a plane S4 that includes the top portions 47a and 47b that are the lower surfaces of the pair of coating layers 42a and 42b. An optical fiber 40 is disposed. The jacket 43 is a region sandwiched between the planes S3 and S4 and is divided around the optical fiber 40 of the pair of coating layers 42a and 42b.

  The jacket 43 is not fused or bonded to the pair of coating layers 42a, 42b from the top portions 46a, 46b, 47a, 47b of the pair of coating layers 42a, 42b to the side surface on the optical fiber 40 side, and the pair of coating layers 42a. , 42b are fused or bonded to the pair of coating layers 42a, 42b outside the top portions 46a, 46b, 47a, 47b.

  The support wire portion 2 includes a support wire 44 extending in the cable longitudinal direction and an outer jacket 45 covering the support wire 44.

  The outer cover 43 of the cable body 1, the neck (outer cover) 3, and the outer cover 45 of the support wire portion 2 are formed integrally. As the material of the jackets 43, 3 and 45, resins such as polyvinyl chloride (PVC), polyethylene (PE), nylon (registered trademark), fluorinated ethylene or polypropylene (PP) can be used.

  Two protrusions 51a, 51b, 52a, 52b are provided on the outside of the covering layers 42a, 42b. The protrusions 51 a, 51 b, 52 a, 52 b are provided at positions different from those immediately below the neck portion 3 so as not to be positioned directly below the neck portion 3. For example, as shown in FIG. 13, an even number of protrusions 51a, 51b, 52a, 52b are provided on the plane S5 including the neck 3 and the pair of strength members 41a, 41b symmetrically.

  According to the optical fiber cable according to the second embodiment of the present invention, even in the case of a self-supporting optical fiber cable, it can be easily taken out from the inside without damaging the optical fiber at the time of intermediate post branching. Can do.

  As shown in FIG. 14, when the protrusion 51 a is provided directly below the neck 3, the outer cover 43 just below the neck 3 is thin and the blade 3 is used to cut the neck 3. There is a possibility that the shear stress concentrates on the portion of the protrusion 51a, and the outer jacket 43 directly under the neck 3 is destroyed. On the other hand, as shown in FIG. 15, by providing the protrusions 51 a, 51 b, 52 a, 52 b at a position different from the position immediately below the neck portion 3, the thickness of the jacket 43 directly below the neck portion 3 can be increased. At the same time, the shear stress when the neck 3 is cut using the blade 60 can be dispersed. As a result, it is possible to prevent cracking directly under the neck 3.

  In the second embodiment of the present invention, the shape of the covering layers 42a and 42b is not particularly limited, and for example, the cross-sectional shape of the covering layers 42a and 42b may be circular as shown in FIG.

  Further, in the second embodiment of the present invention, the protrusions 51a, 51b, 52a, 52b may not necessarily be provided symmetrically with respect to the plane S5 unless they are arranged directly below the neck 3. It may be provided. For example, as shown in FIG. 17, two protrusions 51a, 51b, 52a, 52b may be provided on the upper side with respect to the plane S5, and one protrusion 51c, 52c may be provided on the lower side. Further, the number and arrangement of the protrusions may be different in each of the coating layers 42a and 42b.

<Example>
As an example of the optical fiber cable according to the second embodiment of the present invention, a self-supporting optical fiber cable shown in FIG. 16 was produced. FRP having a diameter of 0.5 mm was used as a pair of strength members 41a and 41b, and HDPE was applied to the outer periphery thereof as coating layers 42a and 42b in a thickness of 0.5 mm to obtain an outer diameter of 1.5 mm. Two of them are arranged in parallel, 8 SR15 optical fibers (made by Fujikura Co., Ltd.) with a thickness of 250 μm are coated between them, and 8 steel wires with a diameter of 1.2 mm are used as support wires. A linear low density polyethylene (LLDPE) jacket 43 was applied. The major axis of the cable body 1 was 4.5 mm, and the minor axis was 2.0 mm.

  At this time, the space for mounting the optical fiber has a circular shape with a diameter of 1.0 mm and is formed on the same plane as the two strength members 41a and 41b. Further, the jacket 43 is separated between the coating layers 42a and 42b and the space for mounting the optical fiber.

  The thickness of the jacket 43 on the strength members 41a and 41b is 0.25 mm, whereas the thickness of the jacket 43 at the thinnest part up to the space where the optical fiber is mounted is 0.5 mm. .

  For the optical fiber cable manufactured in this way, by using a tool having a blade length of 0.25 mm or more and less than 0.5 mm, the top portions 14a and 14b of the coating layers 42a and 42b are cut. The internal optical fiber can be easily taken out.

  When the length of the blade is actually 0.35 mm and the inner optical fiber is taken out by cutting 150 mm in the cable longitudinal direction, the maximum loss increase is 0.01 dB or less, and the branching operation in the live state Can be performed satisfactorily.

  Moreover, although the incision was made using the above-mentioned blade aiming at the thinnest portion of the jacket 43 with respect to the cable center, that is, the space for mounting the optical fiber, the optical fiber was not damaged at all. Therefore, it is possible to prevent the optical fiber from being damaged even if an unexpected situation such as making a cut at a wrong place occurs.

(Other embodiments)
As described above, the present invention has been described according to the first and second embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, as shown in FIG. 18, it is not a self-supporting structure, but has a structure in which at least two structures 61 a and 61 b similar to the cable main body 1 are connected and these are connected via a connecting part 62. Thus, the present invention can be applied to a case where the connecting portion 62 is cut and used. The structure 61a includes an optical fiber 70a, a pair of strength members 71a and 71b disposed so as to sandwich the optical fiber 70a, a pair of coating layers 72a and 72b covering the pair of strength materials 71a and 71b, and an optical fiber. 70a and a jacket 73a that collectively covers the pair of coating layers 72a and 72b. Two protrusions 81a, 81b, 82a, and 82b are provided on the outer sides of the pair of covering layers 72a and 72b in two planes symmetrical with respect to the plane S6. The structure 61b includes an optical fiber 70b, a pair of strength members 71c and 71d disposed so as to sandwich the optical fiber 70b, a pair of coating layers 72c and 72d covering the pair of strength materials 71c and 71d, and an optical fiber. 70b and a jacket 73b that collectively covers the pair of coating layers 72c and 72d. Two protrusions 83a, 83b, 84a, and 84b are provided on the outer sides of the pair of covering layers 72c and 72d in two planes symmetrical with respect to the plane S6.

  In the structure shown in FIG. 1, a part of the top portions 14 a and 14 b that are the upper surfaces of the coating layers 12 a and 12 b on the side far from the optical fiber may be bonded or fused to the jacket 13. In this case, a cut may be made inside the portion where the covering layers 12a and 12b and the outer cover 13 are bonded or fused.

  Further, in the first embodiment of the present invention, as shown in FIG. 1, a case where the cable core 10 has a cylindrical space for storing an optical fiber will be described. In the second embodiment of the present invention, As shown in FIG. 13, the case where the space for storing the optical fiber 40 is substantially cylindrical has been described. However, the space for storing the optical fiber is not limited to the cylindrical shape, and may have various shapes. . For example, as shown in FIG. 19, the space in which the optical fiber 40 is accommodated may be a rectangular shape having a rectangular cross-sectional shape. Moreover, as shown in FIG. 20, the space which accommodates the optical fiber 40 may have the shape matched with the shape of optical fibers 40, such as an optical fiber core wire or an optical fiber tape core wire.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Cable main-body part 2 ... Support wire part 3 ... Neck part 10 ... Cable core 11a, 11b, 41a, 41b, 71a-71d ... Strength body 12a, 12b, 42a, 42b, 72a-72d ... Covering layer 13, 43, 45 73a, 73b ... jacket 14a, 14b, 15a, 15b, 18a, 18b, 46a, 46b, 47a, 47b ... top 16a, 16b, 17a, 17b ... side face 21a, 21b, 22a, 22b, 60 ... blade 23a, 23b ... Interfaces 31a to 31c, 32a to 32c, 51a to 51c, 52a to 52c, 81a, 81b, 82a, 82b, 83a, 83b, 84a, 84b ... Projection 33a, 33b ... Adhesive resin layer 34 ... Plastic film 35a, 35b, 36a, 36b ... color band 37a, 37b, 38a, 38b ... printed layer 39a, 39b ... groove 4 , 70a, 70b ... optical fiber 44 ... support wire 61a, 61b ... structure 62 ... connecting portion F1, F2 ... stress I1 to I4 ... interface S1 to S6 ... plane T1, T2 ... thickness

Claims (11)

Optical fiber,
A pair of strength members disposed in parallel to the optical fiber with the optical fiber in between;
A pair of coating layers respectively covering the pair of strength members;
A jacket for collectively covering the optical fiber and the pair of coating layers;
The optical fiber is disposed at a position sandwiched between a pair of planes including the tops of the pair of coating layers,
In the region sandwiched between the pair of planes and around the optical fiber, the jacket is divided,
The jacket is not fused or bonded to the pair of coating layers from the top of the pair of coating layers to the side surface on the optical fiber side, and is more from the optical fiber than the top of the pair of coating layers. An optical fiber characterized in that, on the far side, the pair of coating layers and the pair of coating layers and a part of the jacket are fused or bonded to each other even after the jacket is divided. cable.   The optical fiber cable according to claim 1, wherein the jacket is wrapped in a region sandwiched between the pair of planes.   3. The optical fiber cable according to claim 1, wherein the top portions of the pair of coating layers form a line in a cross section perpendicular to the longitudinal direction of the cable. 4. The projection for fusing or adhering to the outer cover is provided on the coating layer on the side farther from the optical fiber than the tops of the pair of coating layers. An optical fiber cable according to the item. A support line portion disposed on a plane including the pair of strength members, and
A connecting portion that connects the outer jacket and the support wire portion;
The optical fiber cable according to claim 4, wherein the protrusion is disposed at a position different from a position directly below the connecting portion, and is not disposed immediately below the connecting portion .   6. The optical fiber cable according to claim 5, wherein an even number of the protrusions are arranged in plane symmetry on a plane including the pair of strength members.   4. The adhesive resin layer for fusing or adhering to the jacket is provided on the side farther from the optical fiber than the top portions of the pair of coating layers. An optical fiber cable as described in 1.   The optical fiber cable according to any one of claims 1 to 7, wherein a hardness of the covering layer is higher than a hardness of the jacket. A plurality of the optical fibers are mounted,
The optical fiber cable according to any one of claims 1 to 8, wherein the plurality of optical fibers are unitized by a plus chip film, a tape, or a thread.   The optical fiber cable according to any one of claims 1 to 9, wherein a color band or a printed layer is provided on a surface of the jacket at a position corresponding to a top portion of the pair of coating layers. The outside of the optical fiber cable according to any one of claims 1 to 10, characterized in that it is parallel to groove formed in said optical fiber is located above the front Symbol optical fiber.

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