JP2011164465A - Optical cable - Google Patents

Abstract

The present invention provides an optical cable in which the outer ring cutting property and the laying workability are improved and the cable jacket and the tension member are prevented from shifting during the laying work.
An optical cable includes a tension member, a tape core wire disposed around the tension member, and a cable for concentrically covering the tension member and the tape core wire with the tension member as a center. The tension member 3 is integrated with the cable jacket 5.
[Selection] Figure 1

Description

  The present invention relates to an optical cable that accommodates a plurality of optical fiber cores.

  In recent years, with the increase in demand for optical fibers, the number of optical cables is increasing. Various optical cables capable of accommodating a plurality of optical fiber cores or a plurality of tape cores have been developed in response to the demand for increasing the number of cores. This tape core wire is formed by arranging a plurality of optical fiber core wires in parallel, for example, 4 cores, and integrating them with a resin to form a tape shape. As an example of an optical cable for housing a plurality of tape cores, a structure shown in FIG. 7 is known (see, for example, Patent Document 1).

  In FIG. 7, reference numeral 100 denotes an optical cable. The optical cable 100 is formed by enclosing a core laminated body composed of a plurality of tape core wires 101 with a protective layer 104 that protects against external force, and covering the outside with a cable jacket 102. Yes. A tension member (hereinafter referred to as a tension member) 103 is embedded in the cable jacket 102. As the protective layer 104, an intervening material such as polypropylene yarn can be used. As a result, even if an external force such as pulling or bending is applied to the optical cable 100, it is difficult to move the tape core 101, or even if the tape core 101 moves, the stress applied to the optical fiber core can be reduced. it can.

JP 2001-66481 A

  The optical cable 100 as described above needs to take out the tape core wire 101 from the cable jacket 102 at the cable end or the middle portion of the cable when connecting the core wires. The cover 102 is cut into pieces and peeled off.

  FIG. 8 is a schematic diagram for explaining an example of a general outer ring cutting procedure, in which 110 indicates an outer ring cutting tool (outer cutter). The outer ring cutting tool 110 includes a tool main body 111 and a blade insertion screw 112. First, the operator sets the tool body 111 at a position where the optical cable 100 is to be cut (S101), and in this state, the blade insertion screw 112 is rotated in the direction shown in the figure, and the blade 113 is attached to the cable jacket 102 of the optical cable 100. Insert (S102). Then, when the operator rotates the tool main body 111 in the illustrated direction in this state, the blade 113 is also rotated accordingly, and the cable jacket 102 is cut in a circle (S103).

  However, in the case of the structure of the optical cable 100, since the rotated blade 113 hits the tension member 103 having high rigidity, only half of the cable jacket 102 can be cut. That is, in the structure in which the two tension members 103 are embedded in the cable jacket 102 outside the protective layer 104 as in the optical cable 100, the ring cannot be cut using the jacket ring cutting tool 110. The cable jacket 102 is removed using a cutter knife or the like, which is a problem in terms of safety and work efficiency.

  The optical cable 100 shown in FIGS. 7 and 8 is usually provided with two tension members 103. Therefore, the optical cable 100 is bent in the direction of bending (in the example of FIG. There is also a problem that the laying workability is not good.

  FIG. 9 is a diagram showing an example of an optical cable in which tension members are arranged at the center. In FIG. 9, reference numeral 120 denotes an optical cable. The optical cable 120 includes an optical fiber core wire 121, a tension member 122, a protective layer 123, a presser winding tape 124, and a cable outer sheath 125. With respect to the above-described problems of the outer ring cutting ability and the laying workability, as shown in FIG. 9, the tension member is arranged at the center of the optical cable, so that the outer ring cutting tool 110 of FIG. 8 is used. It can be easily cut. In addition, by arranging one tension member at the center of the optical cable, the direction of bending does not occur, so that the laying operation is facilitated.

  However, normally, when laying the optical cable 120 shown in FIG. 9, the central tension member 122 is gripped by a terminal device such as a pooling eye and the traction laying is performed. However, the tension member 122 is integrated with the cable jacket 125. Therefore, the cable jacket 125 may be separated from the tension member 122 due to an obstacle such as an obstacle in the laying route, and the cable jacket 125 may be shifted in a direction opposite to the pulling direction of the optical cable 120. It was.

  The present invention has been made in view of the above circumstances, and is an optical cable that improves the outer ring cutting property and the laying workability, and further prevents the cable jacket and the tension member from shifting during the laying work. It aims to provide.

  An optical cable according to the present invention includes a tension member, a plurality of optical fiber cores arranged around the tension member, and a cable for concentrically covering the tension member and the plurality of optical fiber cores around the tension member. The tension member is integrated with the cable jacket.

Desirably, the plurality of optical fiber cores are twisted around the tension member in a spiral or SZ shape.
Desirably, a protective layer for protecting a plurality of optical fiber cores is provided, and the protective layer surrounds the tension member and is formed in a C-shaped section or a U-shaped section.
Desirably, both ends of the protective layer are disposed so as to face each other with the tension member interposed therebetween, and a tear string for tearing the cable jacket is provided at both ends.
Preferably, the cable jacket has a protrusion or a groove corresponding to the position so that the position where the tear string is provided can be seen.

  According to the present invention, since the tension member is arranged at the center of the optical cable and the tension member and the cable jacket are integrated, the outer ring cutting property and the laying workability are improved, and further, the cable jacket during the laying work is improved. And the tension member will not shift.

It is a figure which shows an example of the optical cable by this invention. It is a figure which shows the example at the time of tearing the optical cable by this invention with one tear string. It is a figure which shows the other example of the optical cable by this invention. It is a figure which shows an example of the change of the cross-sectional shape of the optical cable at the time of adding twist. It is a schematic diagram for demonstrating an example of the jacket ring cutting procedure which concerns on this invention. It is a figure for demonstrating an example of the method of removing the cable jacket of the optical cable cut in accordance with the outer ring cut procedure demonstrated in FIG. It is a figure which shows an example of the optical cable for accommodating several tape core wires. It is a schematic diagram for demonstrating an example of a general jacket ring cutting procedure. It is a figure which shows an example of the optical cable arrange | positioned centering on the tension member.

Hereinafter, preferred embodiments of the optical cable of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of an optical cable according to the present invention, in which 1 denotes an optical cable. The optical cable 1 includes an optical fiber core wire 2, a tension member 3, a protective layer 4, and a cable jacket 5.

  The optical fiber core 2 is formed by arranging four optical fiber cores in parallel and integrating them with an ultraviolet curable resin into a tape shape. The optical fiber core 2 is not limited to a tape core, but may be a plurality of single-core optical fibers arranged side by side. Hereinafter, this will be described as a tape core wire 2.

  The tension member 3 is also called a strength member, and a wire rod having a resistance to tension and compression is used. As this wire, for example, a steel wire or FRP (Fiber Reinforced Plastics) is used. The protective layer 4 is formed of polypropylene yarn or the like, and protects the tape core wire 2 from external force or the like. The cable jacket 5 is formed of a thermoplastic resin such as an olefin resin (for example, polyethylene). Note that, for example, an adhesive (for example, an olefin-based resin) for imparting adhesiveness to the cable jacket 5 is used on the outside of the tension member 3, but the tension member 3 can be used without using an adhesive. Adhesiveness may be imparted by applying a process such as roughening the surface.

  The main characteristic part of the present invention is to improve the outer ring cutting property and the laying workability, and to prevent the cable jacket and the tension member from shifting during the laying work. As a configuration for this purpose, the optical cable 1 includes a tension member 3, a plurality of tape core wires 2 disposed around the tension member 3, and the tension member 3 and the tape core wire 2 concentrically around the tension member 3. The tension member 3 is integrated with the cable jacket 5.

  As described above, since the tension member 3 is arranged at the center of the optical cable 1, the cable jacket 5 can be easily cut, and the optical cable 1 can be easily bent without causing bending. it can. Even when the central tension member 3 is gripped by a terminal tool such as a pooling eye and the traction laying is performed, the tension member 3 and the cable jacket 5 are integrated, so that the cable jacket 5 and the tension during the laying operation are integrated. The member 3 is not displaced.

  Moreover, the tape core wire 2 may be twisted around the tension member 3 in a spiral shape or an SZ shape as shown in FIG. If it is twisted in a spiral or SZ shape, the fiber distortion in the state of being wound on the winding frame can be canceled, and the transmission characteristics of the optical fiber can be stabilized. In addition, the winding pitch at the time of twisting in a spiral shape or SZ shape is, for example, 500 mm. In addition, the reversal angle in the SZ shape is preferably set to 275 ° from the viewpoint of strain cancellation at the time of bending.

  The protective layer 4 is made of polypropylene yarn or the like, has a role of protecting the tape core wire 2 and surrounds the tension member 3 and is formed in a C-shaped section or a U-shaped section. With such a shape, the tension member 3 and the cable jacket 5 can be easily integrated.

  Here, in the structure in which the tension member 3 is arranged at the center, when the cable jacket 5 is torn in the longitudinal direction with a single tear string, the cable jacket 5 is torn in the longitudinal direction as shown in FIG. A tear 5 'is formed. And when an operator takes out the internal tape core wire 2, it is necessary to widen the cable jacket 5 from both sides of the tear 5 'to both sides, and there is a problem that workability is not good. Moreover, when removing the cable jacket 5 from the internal tape core 2, the tape core 2 may be damaged at the edge of the cable jacket 5, which is not preferable.

  FIG. 3 is a diagram showing another example of the optical cable 1 according to the present invention. In the figure, 6 is a tear string, and 7 is a string position specifying projection. In the case of this example, both ends of the protective layer 4 are arranged so as to face each other with the tension member 3 interposed therebetween, and a tear string 6 for tearing the cable jacket 5 is provided at both ends. As shown in FIG. 3A, the tear string 6 may be provided so that the entire tear string 6 is provided in both end portions of the protective layer 4 adjacent to the cable jacket 5, or as shown in FIG. As shown in FIG. 3, a part of the tear string 6 may be provided so as to be embedded in the cable jacket 5. However, in any case, the tear string 6 needs to be arranged so as to be inside the cross section to be cut, and not to be cut at the time of the ring cut.

  As shown in FIG. 3B, if a part of the tear string 6 is embedded in the cable jacket 5, the position of the tear string 6 is prevented from being shifted due to the influence of bending or pulling when the cable is laid. be able to. If the entire tear string 6 is embedded in the cable jacket 5, the cable jacket 5 may be left uncut at the time of tearing. Therefore, a part of the tear string 6 is embedded in the cable jacket 5, and the remaining It is desirable that the portions are disposed at both ends of the protective layer 4 adjacent to the cable jacket 5.

  Further, the cable jacket 5 may have a protrusion or a groove corresponding to the position so that the position where the tear string 6 is provided can be seen. Although the string position specifying protrusion 7 is illustrated here, a groove may be formed so that the position of the tear string 6 can be understood instead of the string position specifying protrusion 7.

  In this way, by inserting the tear string 6 at both ends of the protective layer 4, the cable jacket 5 can be torn in the longitudinal direction by the tear string 6 after the cable jacket 5 is cut in a circle. Further, the operator can easily specify where the tear string 6 is embedded with the string position specifying protrusion 7. As a result, the cable jacket portion including the tension member 3 and the other cable jacket portions can be separated, so that the internal tape core wire 2 can be easily taken out without being damaged at the edge of the cable jacket. it can.

  FIG. 4 is a diagram illustrating an example of a change in the cross-sectional shape of the optical cable when twisting is applied. Here, the optical cable illustrated in FIG. 3B is illustrated. 4A shows an example of a change in the cross-sectional shape when the tape core wire 2 is spirally wound around the tension member 3, and FIG. 4B shows the tape core wire 2 around the tension member 3. The example of a change of the cross-sectional shape at the time of twisting in SZ shape is shown.

4A, the cross-sectional shape changes in the order of the initial state, 1/4 pitch, 1/2 pitch, and 3/4 pitch, and the same cross-sectional shape as the initial state is obtained at 1 pitch. In FIG. 4B,
The cross-sectional shape changes in the order of the initial state, the first reverse portion (135 °), and the second reverse portion (135 °), and the cross-sectional shape is the same as that of the initial state at one pitch. As described above, by twisting the tape core wire 2 around the tension member 3 in a spiral or SZ shape, the fiber distortion in the state of being wound around the winding frame can be offset, and the transmission characteristics of the optical fiber can be reduced. Stabilization can be achieved.

  FIG. 5 is a schematic diagram for explaining an example of the outer ring cutting procedure according to the present invention. Since the outer ring cutting tool 110 is the same as that shown in FIG. 8 described above, description thereof is omitted here. In this example, the case where the optical cable 1 shown in FIG.

  First, the operator sets the tool body 111 at a position where the optical cable 1 is to be cut (S1), and in this state, the blade insertion screw 112 is rotated in the direction shown in the figure, and the blade 113 is placed on the cable jacket 5 of the optical cable 1. Insert (S2). Then, when the operator rotates the tool main body 111 in the illustrated direction in this state, the blade 113 is also rotated accordingly, and the cable jacket 5 is cut in a circle (S3). As described above, since the tension member 3 is disposed at the center of the optical cable 1, the cable jacket 5 can be easily cut by the jacket ring cutting tool 110.

  FIG. 6 is a diagram for explaining an example of a method for removing the cable jacket of the optical cable 1 that has been cut in accordance with the outer ring cutting procedure described in FIG. 5. In the figure, C1 to C3 indicate ring cutting positions. The worker cuts the three parts C1 to C3 using the tool 110 for cutting the jacket according to the procedure for cutting the jacket described with reference to FIG. At this time, the length of C1 to C2 is about 2 cm. Then, for example, the worker removes the outer cover portion (about 2 cm) corresponding to the cut C1 to C2 using a tool such as a cutter knife, and takes out the two tear strings 6 inside. In addition, the jacket part of C1-C2 should just be removed to such an extent that the two tear strings 6 can be taken out, and does not need to be removed completely.

  Next, the operator pulls the two torn strings 6 that have been taken out in the longitudinal direction of the cable jacket 5 (in the direction of the arrow in the figure) to the ring cut portion C3. Then, since the jacket portion corresponding to C2 to C3 is separated into the cable jacket portion including the tension member 3 and the other cable jacket portion, the cable jacket portion that covers the tape core wire 2 is separated. Easy to remove. And the core wire 2 in the protective layer 4 can be taken out, and the core wire connection work can be performed.

DESCRIPTION OF SYMBOLS 1,100,120 ... Optical cable, 2,101 ... Optical fiber core wire (tape core wire), 3,103,122 ... Tension member, 4,104,123 ... Protective layer, 5,102,125 ... Cable jacket, DESCRIPTION OF SYMBOLS 6 ... Tear string, 7 ... Protrusion for string position specification, 110 ... Jacket cutting tool, 111 ... Tool main body, 112 ... Blade insertion screw, 113 ... Blade, 121 ... Optical fiber core wire, 124 ... Holding tape

Claims (5)

A tension member, a plurality of optical fiber cores arranged around the tension member, and a cable jacket for concentrically covering the tension member and the plurality of optical fiber cores around the tension member An optical cable with
The optical cable, wherein the tension member is integrated with the cable jacket.   2. The optical cable according to claim 1, wherein the plurality of optical fiber cores are twisted around the tension member in a spiral or SZ shape.   2. A protective layer for protecting the plurality of optical fiber cores, wherein the protective layer surrounds the tension member and is formed in a C-shaped section or a U-shaped section. Or the optical cable of 2.   The both ends of the said protective layer are arrange | positioned so that it may oppose on both sides of the said tension member, The tearing string for tearing the said cable jacket is provided in this both ends, The Claim 3 characterized by the above-mentioned. The optical cable described.   The optical cable according to claim 4, wherein the cable jacket has a protrusion or a groove corresponding to the position where the tear string is provided so that the position where the tear string is provided can be seen.

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