JP2005128423A - Optical fiber cable and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent fracture of a secondary coated optical fiber and to make it led out more easily, in tearing a cable sheath with a detacher. <P>SOLUTION: An optical fiber cable 1 is composed of: a secondary coated optical fiber 3 consisting of a single or a plurality of primary coated optical fibers or coated optical tapes; a tension body 9 arranged on both sides of the secondary coated optical fiber 3 along its longitudinal direction; a tear cord 11 arranged at least on one side of the secondary coated optical fiber 3 in a second direction orthogonal to the first direction connecting the tension bodies 9 in a plane vertical to the longitudinal direction; and a long optical element part in which the secondary coated optical fiber 3, the tension bodies 9 and the tear cord 11 are covered with a cable sheath 13. In addition, the optical fiber cable is provided with at least one notched part 17 each on the surface of the cable sheath 13 on the outer side of the tear cord 11 in the second direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pull-down optical fiber cable and a manufacturing method thereof.

  About 1 or 2 cores are usually used as optical fiber cables (drop cables) for premises and aerials. However, with the expansion of FTTH (Fiber to the home), it is about 4 to 10 cores for small-scale condominiums and buildings. Multi-center demand is expected.

  Further, from the viewpoint of the post-branch workability, it is considered effective to use a single strand (or a tape optical fiber core having about two cores) as the optical fiber core to be housed.

  When an attempt is made to design a multi-fiber dropping optical fiber cable including a single optical fiber, a loose tube cable, a slot cable, and the like are conceivable. A cable that follows the simple drop-indoor cable 101 with a small diameter as shown in FIG. That is, in FIG. 10, a drop indoor cable 101 is, for example, an eight optical fiber 103 and an optical element strength member 105 disposed on both sides in parallel to the vicinity of the optical fiber 103 and covered with a cable sheath 107. A notch portion 109 is formed on the surface of the cable sheath 107 on both sides (up and down in FIG. 10) of the optical fiber 103 in a direction perpendicular to the direction in which the optical element strength members 105 are connected. is there. In FIG. 10, eight optical fiber strands 103 are accommodated, but there is also an optical fiber cable that accommodates one or a plurality of optical fiber strands or optical fiber ribbons (see, for example, Patent Document 1).

  Referring to FIG. 11, the optical fiber drop cable 111 is a long cable in which the cable sheath 107 of the drop / indoor cable 101 is covered with the support wire 113 with the same sheath material 115 as the cable sheath 107. The support line portions 117 are integrated in parallel with each other via a neck portion 119. In FIG. 11, eight optical fiber strands 103 are accommodated, but there are also optical fiber cables that accommodate one or a plurality of optical fiber strands or optical fiber ribbons (for example, see Patent Document 2).

  The above-described conventional drop / indoor cable 101 and optical fiber drop cable 111 can be used by tearing the cable sheath 107 from the notch portion 109 by hand and taking out the internal optical fiber 103.

  As functions required for FTTH wiring, in order to provide a highly reliable optical transmission line in addition to optical characteristics, lightning surge current interruption and excessive external tension interruption are required. In order to satisfy this function, an optical fiber drop cable 111 drawn into the house side from an access point such as a closure of an aerial optical cable and a drop indoor cable 101 wired to the optical access device in the house are mainly outdoor on the wall surface of the house. It is connected in the termination optical cabinet.

  At this time, in order to satisfy the required function, the optical element strength member 105 of the optical fiber drop cable 111 must be once cut and then drawn into the house. However, since the cross-sectional structure of the optical fiber drop cable 111 is tight, the optical fiber strand 103 must be cut at the same time in order to cut the optical element tensile member 105 without damaging the optical fiber strand 103. Instead, the cut optical fiber 103 is connected to the optical fiber 103 of the drop indoor cable 101 by a connection point.

  In recent years, in order to perform wiring so that no connection point is provided between the access point and the optical access device, as shown in FIGS. 12 to 14, the optical fiber drop cable 111 or the drop indoor cable 101 is By using an extraction jig called a drop detacher 123 (hereinafter simply referred to as “detacher”) having a claw portion (blade) 121 at an intermediate point in the longitudinal direction, an optical fiber strand 103 is provided. It is possible to separate and cut the optical element strength member 105 without causing damage.

  That is, as shown in FIGS. 12 and 13, the optical element strength member 105 is sandwiched from above the cable sheath 107 by the left and right clamps 125 of the detacher 123 around the notch 109 of the optical fiber drop cable 111. After the claw portions 121 of the left and right clamps 125 are brought into contact with the notch portions 109, the left and right clamps 125 are spread in the left-right direction of the arrow as shown in FIG. As a result, the cable sheath 107 is torn from the notch 109 to the center of the cable where the optical fiber 103 is located, and the optical fiber 103 is peeled off.

In the state where the optical element tensile member 105 is sufficiently separated from the optical fiber 103, the optical element tensile member 105 is cut. The stripped optical fiber 103 is accommodated in an outdoor termination optical cabinet.
JP 2003-202471 A JP 2000-28877 A

  By the way, in the conventional optical fiber cables 101 and 111, when the detacher 123 is opened or the intermediate rear branch is performed, the claw portion 121 of the detacher 123 is applied to the notch portion 109, and the cable sheath 107 is left and right from the notch portion 109. There is a problem that the tip of the claw portion 121 of the detacher 123 may hit the optical fiber 103 and be broken when it is torn.

  In addition, even after the cable sheath 107 is cut by the detacher 123, the cable sheath 107 may be divided into left and right by hand if the necessary length is opened or branched after the middle. At this time, there is a problem that the optical fiber 103 that is in close contact with the cable sheath 107 may be greatly bent together with the cable sheath 107 or the optical fiber 103 may be broken.

  The present invention has been made to solve the above-described problems.

An optical fiber cable of the present invention includes an optical fiber core wire,
Strength members disposed on both sides of the optical fiber along the longitudinal direction of the optical fiber,
A tearing strip disposed on at least one side of the optical fiber core in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the longitudinal direction of the optical fiber;
A cable sheath for covering the optical fiber core wire, the tensile body, and the tearing wire body, and outside the tearing wire body in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core wire. A cable sheath having at least one notch formed on the surface of the cable sheath;
It has a long optical element part provided with.

  The optical fiber cable according to the present invention is a long cable support line portion in which the support line is covered with a sheath in the optical fiber cable, and the cable support line portion is arranged in parallel with the optical element portion and integrated. It is preferable to have.

  In the optical fiber cable according to the present invention, it is preferable that the optical fiber core has one or a plurality of strands or tape cores.

  In the optical fiber cable of the present invention, in the optical fiber cable, a straight line connecting tearing strips disposed on both sides of the optical fiber core wire in a plane orthogonal to the longitudinal direction of the optical fiber core wire is While intersecting with the boundary line of the shape of the hole formed in the cable sheath by the optical fiber core wire, the straight line connecting the point closest to the tearing line of each notch may intersect with the tearing line. preferable.

  In the optical fiber cable of the present invention, it is preferable that the straight line is parallel to the second direction in the plane.

An optical fiber cable manufacturing method according to the present invention includes an optical fiber core, tensile strength members disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and a longitudinal direction of the optical fiber core. And a tear line disposed on at least one side of the optical fiber core wire in a second direction orthogonal to the first direction connecting the strength members in a plane perpendicular to each of the fibers, and each of them is fed to the extrusion head. Process,
Extruding a thermoplastic resin into the extrusion head;
Forming an optical element portion in which a cable sheath covers the optical fiber core wire, the tensile body, and the tearing wire body, wherein the optical fiber core wire extends in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core wire. Forming an optical element portion including a step of forming a notch portion on the surface of the cable sheath outside the tearing line; and
It is characterized by having.

An optical fiber cable manufacturing method according to the present invention includes an optical fiber core, tensile strength members disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and a longitudinal direction of the optical fiber core. A tear line disposed on at least one side of the optical fiber core wire in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the support, and a support wire, respectively, Supplying the head;
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire, the tensile strength member, and the tear strip are covered with a cable sheath, and a cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and are integrally formed. Forming a step including forming a notch on the surface of the cable sheath outside the tearing line in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core; ,
It is characterized by having.

  An optical fiber cable manufacturing method according to the present invention includes a step of supplying the optical fiber core wire, a tensile body, and a tearing strip to the extrusion head, and a thermoplastic resin to the extrusion head in the optical fiber cable manufacturing method. The supplying step is preferably performed simultaneously.

  As can be understood from the means for solving the problems as described above, according to the present invention, since the tear line is placed in the vicinity immediately below the apex of the notch, the notch is cut. Later, it becomes easy to tear the cable sheath by pulling the tearing striated body, and the lead-out and the intermediate rear branch can be performed in a short time.

  In addition, since the tear filament is interposed between the notch portion and the optical fiber, the tear filament acts as a buffer layer when the notch portion is cut using the claw portion of the detacher. And since it is the structure where a nail | claw part does not contact | win an optical fiber strand directly, the fracture | rupture of an optical fiber strand can be prevented effectively.

  Moreover, the optical fiber cable can be quickly manufactured in a series of continuous processes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1, an optical fiber cable 1 according to a first embodiment of the present invention has, for example, a plurality of optical fiber strands 3 as optical fiber core wires. Here, eight optical fiber strands 3 are arranged. Each of the optical fiber strands 3 is, for example, coated on the outer circumference of a 125 μmφ quartz glass 5 with a UV resin 7 to 250 μmφ.

  In the vicinity of both sides (left and right in FIG. 1) of the optical fiber 3 along the longitudinal direction of the optical fiber 3, the optical element tensile body 9 is arranged in parallel with the optical fiber 3. ing. Furthermore, in a plane perpendicular to the longitudinal direction of the optical fiber 3 described above, a direction (vertical direction in FIG. 1; second direction) in a direction orthogonal to the arrangement direction (first direction) for connecting the optical element strength members 9 is shown. For example, a tear string 11 as a tear line is vertically arranged on both sides of the optical fiber 3.

  The optical fiber 3, the optical element strength member 9, and the tear string 11 are covered with a cable sheath 13 made of a thermoplastic resin to constitute a long optical element portion 15. A notch portion 17 is formed on the surface of the cable sheath 13 located on both outer sides (up and down in FIG. 1) of the tear string 11 in the second direction in the plane perpendicular to the longitudinal direction of the optical fiber 3. ing. The eight optical fiber strands 3 are disposed in the hollow portion 19 of the cable sheath 13.

  Further, as the tear string 11, one that has a high tensile strength and is not fused to the cable sheath 13 by heat during extrusion molding is suitably used. In this embodiment, a polyester twisted string is used.

  Further, the position in the cable sheath 13 into which the tear string 11 is inserted needs to be between the notch portion 17 and the optical fiber 3 in consideration of the lead-out or intermediate post-branching property. Therefore, in the plane orthogonal to the longitudinal direction of the optical fiber 3, the surface 21 (straight line) connecting the opposing tear strings 11 preferably intersects with the boundary line of the hollow portion 19 of the cable sheath 13. A tear string so that a straight line connecting the vertices 17a and 17b of the portion 17 (same as the straight line 21 in this embodiment) intersects the boundary line of the hole shape formed in the cable sheath 13 by the tear string 11 11 is provided. The tear string 11 may be in contact with the optical fiber 3 as long as the tear string 11 is positioned between the notch portion 17 and the optical fiber 3.

  In the above configuration, the tear string 11 is present between the notch portion 17 and the optical fiber strand 3, whereby the tearability of the cable sheath 13 is facilitated, and the optical fiber strand 3 is formed at the time of opening or intermediate rear branching. The risk of breakage can be reduced.

  More specifically, referring to FIG. 3 to FIG. 5, the extraction or middle of the optical fiber strand 3 of the optical fiber cable 1 using an extraction jig called a detacher 25 with a claw portion (blade) 23. When the rear branch is performed, as shown in FIG. 3 and FIG. 4, an arbitrary intermediate point in the longitudinal direction of the optical fiber cable 1 is used for the optical element with the notch portion 17 of the optical fiber cable 1 as the center. The strength member 9 is fixed by being sandwiched from above the cable sheath 13 by the left and right clamps 27 of the detacher 25. At this time, the claw portions 23 of the left and right clamps 27 are brought into contact with the notch portion 17, but since the tear string 11 exists between the notch portion 17 and the optical fiber 3, the tear string 11 serves as a buffer layer. Thus, the tip of the claw portion 23 of the detacher 25 does not contact the optical fiber 3 and is protected.

  Thereafter, as shown in FIG. 5, the left and right clamps 27 are expanded in the left-right direction of the arrow, so that the center portion of the cable with the optical fiber 3 passes through the hole formed by the tear string 11 from the notch portion 17. The cable sheath 13 is torn to the (hollow part 19), and the optical fiber 3 is stripped.

  Therefore, the optical element tensile member 9 is easily separated and cut without damaging the optical fiber 3.

  In addition, when the cable sheath 13 is cut by the detacher 25 as described above, the cable sheath 13 may be divided into left and right when it is opened to the required length or branched after the middle. The cable sheath 13 can be easily torn while the string 11 is taken out, and the optical fiber 3 can be easily taken out. Therefore, the conventional situation that the optical fiber 3 is brought into close contact with the cable sheath 13 and bent together with the cable sheath 13 to break the optical fiber 3 can be avoided.

  FIG. 2 shows an optical fiber cable 1 according to a second embodiment of the present invention. The optical fiber cable 1 has a long optical element portion 15 similar to that shown in FIG. The optical fiber cable 1 further includes a long cable support line portion 33 in which the support line 29 is covered with a sheath 31. The support wire 29 is made of, for example, a steel wire. The sheath 31 is a thermoplastic resin and is formed integrally with the cable sheath 13. Therefore, the cable support line portion 33 is integrated with the optical element portion 15 in parallel via the neck portion 35. In addition, in the plane orthogonal to the longitudinal direction of the optical fiber 3, the support wire 29, the pair of tensile elements 9 for optical elements, and the optical fiber 3 are arranged in alignment along the first direction. .

  With this configuration, the optical fiber cable 1 has the long cable support wire portion 33 in which the support wire 29 is covered with the sheath 31 and is integrated with the optical element portion 15 via the neck portion 35 in parallel with each other. It can be used as an optical fiber drop cable and has the same effect as the effect in FIG.

  In the optical fiber cables 1 according to the first and second embodiments described above, eight optical fiber strands 3 are used as the optical fiber core wires. Wires or tape cores may be used. In particular, a 0.25 mm strand is most preferably used, but a 2-core tape core or a single core of about 0.4 to 0.9 mm is also used.

  As the optical element strength member 9, a steel wire, FRP, or the like is preferably used, and the support wire 29 is a steel wire.

  In the first and second embodiments described above, a gap is formed between the eight optical fiber strands 3 in the hollow portion 19 of the cable sheath 13. Without providing the hollow portion 19, the eight optical fiber strands 3 may be fully extruded and closely adhered at the time of extrusion molding. In this case, as shown in FIG. 1, in the plane orthogonal to the longitudinal direction of the optical fiber 3, the straight line (surface) 21 connecting the tear strings 11 is a cable by the optical fiber 3. Crossing the boundary line of the shape of the hole (portion corresponding to the hollow portion 19) formed in the sheath 13 is desirable in terms of improving the lead-out property of the optical fiber 3.

  Next, a method for manufacturing the optical fiber cable 1 shown in FIG. 2 will be described.

  Referring to FIG. 6, a production line for forming an optical fiber cable 1 is illustrated, including eight optical fiber wires 3, two optical element strength members 9, two tear strings 11, and a support wire. 29 are respectively supplied from bobbins 37, 39, 41, and 43 and fed into the extrusion head 47 of the extrusion device 45. A pair of optical element tensile bodies 9 are arranged in parallel on both sides of the eight optical fiber strands 3, and the optical element tensile strength is within a plane perpendicular to the longitudinal direction of the optical fiber strand 3. Predetermined positions in the extrusion head 47 of the extrusion device 45 arranged on both sides of the optical fiber 3 in a direction (vertical direction in FIG. 1; second direction) orthogonal to the arrangement direction (first direction) connecting the bodies 9 The support wire 29 is also supplied to a predetermined position in the extrusion head 47.

  More specifically, referring to FIG. 7, a cross-sectional view of the extrusion head 47 is shown, and a nipple portion 49 as shown in FIG. At the same time, as shown in FIG. 9, a die portion 53 having a die hole 51 having substantially the same shape as the outer peripheral shape of the cross section of the optical fiber cable 1 of FIG. 2 is provided on the outer periphery of the nipple portion 49. ing. In this case, projections 55a and 55b for forming the notch portion 17 are provided in the die hole 51 at a position corresponding to the notch portion 17 of the cable 1 of FIG. Between this die part 53 and the said nipple part 49, the flow path 57 in which the thermoplastic resin P as a sheath is extruded is provided.

  Further, as shown in FIG. 8, for example, a nipple hole 59 is formed in the nipple portion 49 as a through hole through which the optical fiber 3 passes, and the nipple hole 59 has a substantially elliptical cross section. In addition, a pipe 61 having a substantially elliptical cross section extending to the front end of the die hole 51 in the extrusion direction (left direction in FIG. 7) is connected to the front of the nipple hole 59 (leftward in FIG. 8). Further, nipple holes 63 through which the optical element strength members 9 pass are provided on both outer sides in the first direction in FIG. 8 of the nipple holes 59. Both nipple holes 59 in the second direction orthogonal to the first direction in FIG. A nipple hole 65 through which the tear string 11 passes is provided outside, and a nipple hole 67 through which the support line 29 passes is formed outside the left nipple hole 63 (left side in the first direction) in FIG.

  7 and FIG. 8, the eight optical fiber strands 3 and the two optical fibers wound on the bobbins 37, 39, 41, and 43 provided on the left side in FIG. The element tension member 9, the two tear strings 11, and the support wire 29 are drawn out and sent into the extrusion head 47. The eight optical fiber strands 3 are sent so as to pass through the nipple hole 59 and the pipe 61 of the nipple portion 49 in the extrusion head 47.

  The two optical element strength members 9 pass through the nipple holes 63 of the nipple portion 49, the two tear strings 11 pass through the nipple holes 65, and one support line 29 is connected to the nipple. An optical fiber cable as shown in FIG. 2 is caused by running through the hole 67 in the left direction in FIGS. 7 and 8 and extruding the molten thermoplastic resin P from the flow path 57 of the die portion 53. 1 can be obtained.

  In short, the manufacturing method of the optical fiber cable 1 has the following characteristics. That is, in this manufacturing method, the extrusion head 47 is used, and this extrusion head 47 has the following.

(1) The tip portion has a truncated cone (or truncated cone) shape, and the tip surface (or truncated surface) 49a has a nipple hole 59 for allowing the optical fiber 3 to pass therethrough, and a pair of tensile elements for optical elements. Nipple portion 49 having a pair of nipple holes 63 for passing 9 and a pair of nipple holes 65 for passing two tear strings 11
(2) The die portion 53, which has a conical inner peripheral surface arranged in parallel with a predetermined interval with respect to the conical surface of the nipple portion 49, and the optical fiber 3 and the optical element strength member 9 A die portion 53 having a die hole 51 for extruding the sheath thermoplastic resin P together with the tear string 11 and the support wire 29.
Here, the cross-sectional area of the nipple hole 59 is larger than the cross-sectional area of the nipple hole 63. The nipple holes 63 are disposed on both sides of the nipple hole 59 in the first direction on the tip surface 49a.

And this manufacturing method has the following processes.
(1) Step of pulling out the optical fiber 3 from the nipple hole 59 (2) Step of pulling out the optical element tensile body 9 from the nipple hole 63 (3) Step of pulling out the tear string 11 from the nipple hole 65 (4) Nipple hole (5) Extruding the thermoplastic resin P together with the optical fiber 3, the optical element tensile member 9, the tear string 11, and the support wire 29 from the die hole 51 (6) With the thermoplastic resin P surrounding the optical fiber 3 in front of the die hole 51 in the direction, the thermoplastic resin P is solidified and the optical element strength member 9, the tear string 11 and the support wire 29 are integrated. The step of drawing out the optical fiber 3 from the nipple hole 59 and the step of drawing out the tensile element 9 for optical element from the nipple hole 63 An extraction step of the tear string 11 from nipple hole 65, and drawn out process of the support line 29 from nipple hole 67, the extrusion step such as a thermoplastic resin P from the die hole 51, are performed simultaneously.

  Moreover, according to the manufacturing method, the optical fiber cable 1 including the optical fiber 3, the optical element strength member 9, the tear string 11, the sheaths 13 and 31, and the support wire 29 is quickly manufactured in a series of continuous processes. I can do it.

  With the above configuration, the molten thermoplastic resin P pushed out from the flow path 57 between the nipple part 49 and the die part 53 passes through between the pipe 61 and the die hole 51 (that is, an optical fiber fed from the nipple hole 59). Solidify (before contact with strand 3). Therefore, as shown in FIG. 2, the optical fiber cable 1 in which gaps are formed between the plurality of optical fiber wires 3 and the sheath 13 in the hollow portion 19 of the cable sheath 13 is obtained.

  In addition, the optical fiber cable 1 as shown in FIG. 1 can be obtained using another dice | dies part, without supplying said support wire 29. FIG.

  Further, according to the above manufacturing method, the optical fiber cable 1 including the optical fiber 3, the optical element strength member 9, the tear string 11, and the sheath 13 is formed in a series as in the manufacturing method in FIGS. It can be manufactured quickly in a continuous process.

  Next, the performance of the optical fiber cable 1 according to the embodiment of the present invention will be described in detail.

  The above-described optical fiber cable 1 having the configuration shown in FIG. 2 was manufactured as an example, and the conventional optical fiber drop cable shown in FIG. 11 was manufactured as a comparative example, and these characteristics were evaluated. The optical fiber cable of the comparative example is the same as the optical fiber cable 1 of FIG. 2 except that the tear string 11 is not interposed.

  In addition, eight single-mode optical fiber strands 3 having a diameter of 250 μm were bundled as the optical fiber core wire, and a polyester twisted cord was used as the tear string 11.

(Comparative test 1)
The optical fiber cables of the example and the comparative example were cut by about 3 cm by the detacher 25, and the intermediate branch was performed by 30 cm in the longitudinal direction of the optical fiber cable. The number of tests is 10 times x 8 cores. The maximum loss fluctuation (transmission loss fluctuation) of each optical fiber cable at this time was measured. The results are shown in Table 1.

In addition, after cutting with the detacher 25, the cable of Example 1 performed the intermediate back branch by pulling the tear string 11 up and down in FIG.2 and FIG.5. On the other hand, the cable of the comparative example was subjected to intermediate rear branching by pulling the cable sheath left and right in FIGS.

  As can be seen from Table 1, there is a clear difference between the cable of the example and the comparative example. That is, in the cable of the comparative example, when the cable sheath is pulled to the left and right, the bending of the wire that is in close contact with the cable sheath becomes large, and thus the transmission loss fluctuation increases. On the other hand, since the cable 1 of the embodiment can tear the cable sheath 13 in a straight state by the tear string 11, the transmission loss fluctuation at the time of intermediate post branching is reduced, and the bending that the optical fiber 3 is subjected to is small. Thus, it can be seen that the risk of breakage of the optical fiber 3 at the time of intermediate branching is reduced.

  Further, when the notch portion 17 is cut by the detacher 25, the cable of the first embodiment has the tear string 11 between the notch portion 17 and the optical fiber 3, so that the tear string 11 serves as a buffer layer. The breakage of the optical fiber 3 can be effectively prevented.

(Comparative test 2)
The lead times for the cable of the example and the cable of the comparative example were compared. Cut the end of each cable by about 1 cm with a blade such as a cutter, tear the sheath for intermediate post branching by 30 cm, and measure the time until separation of the optical fiber 3 and cable sheath 13 is completed. did. The number of measurements is 10 times. The results are shown in Table 2.

  As can be seen from Table 2, it was found that the cable of the example can shorten the time required for lead-out to half the time of the cable of the comparative example.

  In other words, when the cable of the comparative example was torn out, it took time to split the cable sheath into left and right while taking care not to break the optical fiber when the cable sheath to which the optical fiber was stuck was torn. . On the other hand, in the cable of the embodiment, after the notch 17 is cut, the cable sheath 13 can be divided into two by pulling the tear string 11 without worrying about the bending of the optical fiber 3. Because it was possible, I could shorten the mouth-out time. Therefore, it can be seen that the extraction has become easy.

  In addition, in the Example, although the optical fiber strand 3 with a diameter of 250 micrometers was used as an optical fiber core wire, the same effect is acquired also when a single optical fiber core wire and an optical fiber tape core wire are used.

  From the above, this embodiment has the following advantages.

  Since the tear string 11 is inserted in the vicinity of the apex of the notch portion 17, the cable sheath 13 can be easily torn by pulling the tear string 11 after the notch portion 17 is cut. An optical fiber drop cable or indoor cable can be obtained in a short time.

  Since the tear string 11 is interposed between the notch part 17 and the optical fiber 3, the tear string 11 serves as a buffer layer when the notch part 17 is cut using the claw part 23 of the detacher 25. Thus, since the claw portion 23 does not directly contact the optical fiber 3, breakage of the optical fiber 3 can be effectively prevented.

It is sectional drawing of the optical fiber cable of 1st Embodiment of this invention. It is sectional drawing of the optical fiber cable of 2nd Embodiment of this invention. It is state explanatory drawing when the optical fiber cable of 1st Embodiment is cut off with a detacher. FIG. 4 is a state explanatory diagram when cutting with a detacher in the process following FIG. 3. FIG. 5 is a state explanatory diagram when cutting with a detacher in the process following FIG. 4. It is a schematic explanatory drawing which shows the manufacturing line of an optical fiber cable. It is sectional drawing of an extrusion head part. It is a perspective view of a nipple part. It is a perspective view of a die part. It is sectional drawing of the conventional optical fiber cable. It is sectional drawing of another conventional optical fiber cable. It is state explanatory drawing when a conventional optical fiber cable is cut with a detacher. FIG. 13 is a state explanatory diagram when cutting with a detacher in the process following FIG. 12. FIG. 14 is a state explanatory diagram when cutting with a detacher in the process following FIG. 13.

Explanation of symbols

1 Optical fiber cable (of the first and second embodiments)
3 Optical fiber (optical fiber core)
9 Tensile element for optical element 11 Tear string (Tearing filament)
13 Cable sheath 15 Optical element part 17 Notch part 17a, 17b Apex 19 of notch part 17 Hollow part 21 surface (straight line)
23 Claw part 25 Detacher 27 Clamp 29 Support line 31 Sheath 33 Cable support line part 35 Neck part 45 Extrusion device 47 Extrusion head 49 Nipple part 53 Die part

Claims (8)

An optical fiber core,
Strength members disposed on both sides of the optical fiber along the longitudinal direction of the optical fiber,
A tearing strip disposed on at least one side of the optical fiber core in a second direction perpendicular to the first direction connecting the strength members in a plane perpendicular to the longitudinal direction of the optical fiber;
A cable sheath for covering the optical fiber core wire, the tensile body, and the tearing wire body, and outside the tearing wire body in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core wire. A cable sheath having a notch formed on the surface of the cable sheath; and
An optical fiber cable comprising a long optical element portion comprising:   2. An optical fiber according to claim 1, wherein the optical fiber has a long cable support line part in which a support line is covered with a sheath, the cable support line part being arranged in parallel with the optical element part and integrated therewith. cable.   The optical fiber cable according to claim 1 or 2, wherein the optical fiber core includes one or a plurality of strands or a tape core.   The shape of the hole formed in the cable sheath by the optical fiber core wire is a straight line connecting the tear strips arranged on both sides of the optical fiber core wire in a plane orthogonal to the longitudinal direction of the optical fiber core wire. The optical fiber according to claim 1, 2 or 3, characterized in that a straight line that intersects the boundary line of each notch portion and a point that is closest to the tearing line body intersects with the tearing line body. cable. The optical fiber cable according to claim 4, wherein the straight line is parallel to the second direction in the plane. An optical fiber core, a tensile body disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and the tensile body are connected in a plane perpendicular to the longitudinal direction of the optical fiber core. Each of a tearing strip disposed on at least one side of the optical fiber core wire in a second direction orthogonal to the first direction, and supplying the extrusion head to the extrusion head;
Extruding a thermoplastic resin into the extrusion head;
Forming an optical element portion in which a cable sheath covers the optical fiber core wire, the tensile body, and the tearing wire body, wherein the optical fiber core wire extends in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core wire. Forming an optical element portion including a step of forming a notch portion on the surface of the cable sheath outside the tearing line; and
An optical fiber cable manufacturing method comprising: An optical fiber core, a tensile body disposed on both sides of the optical fiber core along the longitudinal direction of the optical fiber core, and the tensile body are connected in a plane perpendicular to the longitudinal direction of the optical fiber core. A step of running a tear wire disposed on at least one side of the optical fiber core wire in a second direction orthogonal to the first direction, and a support wire, respectively, and supplying the run head to the extrusion head;
Extruding a thermoplastic resin into the extrusion head;
An optical element portion in which the optical fiber core wire, the tensile strength member, and the tear strip are covered with a cable sheath, and a cable support wire portion in which the support wire is covered with a sheath are arranged in parallel and are integrally formed. Forming a step including forming notches on the surface of the cable sheath on both outer sides of the tear strip in the second direction in a plane perpendicular to the longitudinal direction of the optical fiber core wire. When,
An optical fiber cable manufacturing method comprising: 8. The optical fiber according to claim 7, wherein the step of supplying the optical fiber core wire, the tensile body, and the tear strip to the extrusion head and the step of supplying the thermoplastic resin to the extrusion head are performed simultaneously. Cable manufacturing method.

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