JP2013083830A - Optical fiber cable and method for tearing optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable which is torn with high workability by giving a tearable configuration to a high-density polyethylene inner layer coating when forming a sheath of the high-density polyethylene inner layer coating and a low-density polyethylene outer layer coating.SOLUTION: A high-density polyethylene inner sheath 31 includes a pair of sting-like separators 5 which are embedded in a low-density polyethylene outer sheath 32 substantially entirely in a length direction, and a part of the outer sides of which reaches the inside of the low-density polyethylene outer sheath. The pair of string-like separators divide the high-density polyethylene inner sheath into a shorter inner sheath portion 31A and a longer inner sheath portion 31B, and integrating means for integrating the shorter inner sheath portion with the low-density polyethylene outer sheath is provided. This integrating means is, for example, a projection 7 which projects outward and is embedded in the low-density polyethylene outer sheath to be integrated with the low-density polyethylene outer sheath.

Description

  The present invention relates to an optical fiber cable and a method for tearing an optical fiber cable.

  As shown in Patent Document 1, a conventional optical fiber cable in which a plurality of optical fiber core wires and a tear string are covered with a primary coating layer of polyamide resin, and further covered with a secondary coating layer of foamed polyethylene from above, Alternatively, an optical fiber cable having a high-density polyethylene or a mixture of high-density polyethylene and low-density polyethylene as an outermost coating layer is known.

  In Patent Document 2, a tensile strength layer made of tensile strength fibers is provided on the circumference of an optical fiber unit obtained by collectively covering a plurality of optical fiber core wires with a unit material, and a sheath is provided on the circumference of the tensile strength layer. Is described. According to the optical fiber cable having such a configuration, the optical fiber tape core wire constituting the optical fiber cable is in the form of an optical fiber unit in which a plurality of optical fiber tape core wires are collectively covered with a resin. The characteristic that rigidity becomes larger than the case of the form of an optical fiber tape core wire is acquired.

  Patent Document 3 describes a structure in which a sheath is provided outside a cylindrical body in which a plurality of optical fiber cores are housed, and a lip cord and a tension member are embedded in the sheath. The sheath is composed of an inner sheath and an outer sheath. It is described that the lip cord and tension member are embedded in this outer sheath.

JP-A-5-215946 JP 11-31730 A JP 2000-241681 A

  As described above, a high-density polyethylene inner layer coating is formed around the cable core so that a large compressive force acts on the optical fiber core to increase the transmission loss of the optical fiber cable, and the low-density polyethylene is formed outside the cable core. It has been practiced to form an outer coating to maintain flexibility. Then, it has been practiced to embed a tearing lip cord and a tension member for imparting tensile strength to the sheath around the cable core.

  When trying to adopt a structure in which a high-density polyethylene inner layer coating is formed around the cable core and a low-density polyethylene outer layer coating is formed outside the cable core, the low-density polyethylene outer layer coating is easy to tear. It is difficult to pull out the optical fiber core wire because it is difficult to tear.

  In view of this point, the present invention forms a high-density polyethylene inner layer coating in a tearing configuration when the outer sheath (sheath) is formed by the high-density polyethylene inner layer coating and the low-density polyethylene outer layer coating, and has good tear workability. An object is to provide an optical fiber cable.

Specifically, the present invention has a cable core formed of a filler disposed around a cylindrical body in which a plurality of optical fiber cores are stored, and a cable core storage region for storing the formed cable core. In an optical fiber cable with a sheath on the outside,
The sheath is formed of two layers of a high hardness inner sheath provided around the cable core and a low hardness outer sheath provided around the high hardness inner sheath;
A tension member, which is a tensile member, is embedded in the longitudinal direction inside the low hardness outer sheath, the high hardness inner sheath or between the low hardness outer sheath and the high hardness inner sheath,
The high-hardness inner sheath is disposed in the high-hardness inner sheath, and a part of the inner side in the longitudinal direction is disposed close to the cable core storage region, and a part of the outer side is the outer part having the low hardness. A set of string-like separators embedded so as to reach the sheath,
The pair of string-shaped separators divides the high hardness inner sheath into a short inner jacket part and a long inner jacket part,
There is provided an optical fiber cable comprising an integration means for integrating the short inner jacket portion with the low density polyethylene outer sheath.

The present invention also includes a cable core formed of a filler disposed around a cylindrical body in which a plurality of optical fiber cores are stored, and a sheath outside the cable core storage region that stores the formed cable core. In an optical fiber cable with
The sheath is formed of two layers, a high density polyethylene inner sheath provided around the cable core and a low density polyethylene outer sheath provided around the high density polyethylene inner sheath,
A tension member, which is a tensile member, is embedded in the longitudinal direction inside the low density polyethylene outer sheath, inside the high density polyethylene inner sheath or between the low density polyethylene outer sheath and the high density polyethylene inner sheath,
The high-density polyethylene inner sheath is disposed within the high-density polyethylene inner sheath and a part of the inner side in the longitudinal direction is close to the cable core storage region, and a part of the outer side is the outer part of the low-density polyethylene. A set of string-like separators embedded so as to reach the sheath,
The pair of string-like separators divides the high-density polyethylene inner sheath into a short inner jacket portion and a long inner jacket portion;
There is provided an optical fiber cable comprising an integration means for integrating the short inner jacket portion with the low density polyethylene outer sheath.

  The present invention also provides an optical fiber cable characterized in that a part of the inner side of the string-like separator described above is in contact with the cable core storage region.

The present invention is also characterized in that the above-mentioned integration means is a protrusion integrated with the low-density polyethylene outer sheath by being buried in the low-density polyethylene outer sheath facing outward. Provide fiber optic cable.

  The present invention also provides an optical fiber cable characterized in that the above-mentioned protrusion forms an inverted trapezoidal wedge shape.

The present invention also provides a method for tearing any one of the optical fiber cables described above.
The low-density polyethylene outer sheath is split into two parts by tearing, and the low-density polyethylene outer sheath on the side where the protrusions are buried is pulled, so that a short inner jacket portion between the pair of separators is formed. From an optical fiber cable characterized in that when a short inner jacket part separated and removed from a long inner jacket part is removed, an extraction space part for taking out the optical fiber core wire is formed. An optical fiber tearing method is provided.

  As described above, the present invention provides a pair of string-like separators on a high-density polyethylene inner sheath, and this set of string-like separators has a high-density polyethylene inner sheath with a short inner jacket portion and a long inner sheath. It is divided into a jacket part, and this short inner jacket part is provided with a projection integrated with the low density polyethylene outer sheath by being embedded in the low density polyethylene outer sheath facing outward. Therefore, when the low-density polyethylene outer sheath is torn and separated into two parts and separated from the cable core, the short inner jacket part has a protrusion due to the provision of an integral means, for example, a protrusion A short inner jacket with the low density polyethylene outer sheath on the side is cut off from the longer inner jacket with the separator as a boundary, forming a space in the cut and removed trace It is possible. Thus, this space can be formed simultaneously with the cutting operation of the low density polyethylene outer sheath, and the space formed in this way can be used as a space for taking out the optical fiber. The take-out operation can be easily performed.

The block diagram which shows the structure of the Example of this invention in a cross section. The flowchart which shows the step for taking out an optical fiber core wire from an optical fiber cable.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an optical fiber cable according to an embodiment of the present invention.

  In FIG. 1, an optical fiber cable 100 includes a cable core 2 that is an aggregate of optical fiber cores and is formed of a filler disposed around a cylindrical body 1 in which a plurality of optical fiber cores are housed. A sheath 3 is provided. The cable core 2 may be configured by combining other members with the filler. The sheath 3 is formed outside the cable core storage area that stores the cable core 2.

  The sheath 3 includes a high-density polyethylene inner sheath (HDPE, hereinafter referred to as an inner sheath) 31 that is a high-hardness inner sheath and a low-density polyethylene outer sheath (LDPE, hereinafter referred to as an outer sheath) that is a low-hardness outer sheath. Formed as a multilayer.

  The inner sheath 31 is provided around the cylindrical cable core storage region, and the outer sheath 32 is provided outside the inner sheath 31 and around the inner sheath 31. The outer layer of the inner sheath 31 and the inner layer of the outer sheath 32 come into contact with each other, and the contraction of the outer sheath 32 is reduced.

  Between the inner sheath 31 and the outer sheath 32, a part of the tension member 4 that is a tensile strength member is embedded in both the inner sheath 31 and the outer sheath 32 in the longitudinal direction. In the drawing, the tension member 4 is disposed at the left and right target points. The tension member 4 may be embedded so as to be embedded in the inner sheath 31 or the outer sheath 32. According to the arrangement shown in the figure, the adhesive layer of the tension member 4 is bonded to the outer sheath 32, so that it is easy to manufacture and the contraction of the outer sheath 32 can be reduced.

  In the above configuration, the tear string 5 is provided so that the entire length is embedded in the inner sheath 31 in the longitudinal direction and a part of the outer side reaches the outer sheath 32. The term “substantially entirely embedded” means that a part of the outer outer side reaches the outer sheath 32, but the inner inner side reaches the cable core storage area or is brought into close contact. . The string-like separator 5 is composed of a pair, and is arranged close to the upper portion in the drawing. Due to this proximity arrangement, the inner sheath 31 is formed by being divided into a short inner jacket portion 31A and a long inner jacket portion 31B. Each of the inner jacket portions 31 </ b> A and 31 </ b> B is in contact with the cable core 2 at a part of the inner side.

  With such a configuration, the inner sheath 31 includes a pair of string-like separators 5 that are substantially entirely buried in the longitudinal direction in the inner sheath 31 and a part of the outer outer side reaches the outer sheath 32. Become.

  The string-shaped separator may be string-shaped, and may be configured in a round shape, a square shape, or other shapes.

  As the string-like separator, a high-strength polymer fiber, a metal wire such as a steel wire, an aluminum wire, or a copper wire, a glass fiber, a cotton strip, or the like can be used.

  A short inner jacket portion 31A formed by being divided by the string-like separator 5 includes a protrusion 7 facing outwardly outward. The protrusion 7 is integrally formed when the inner sheath 31 is formed, and is formed into an inverted trapezoidal wedge shape. The shape of the separator 5 does not have to be an inverted trapezoidal shape, but is preferably a wedge shape.

  The protrusion 7 is formed by being embedded in the outer sheath 32. Therefore, when the inner sheath 31 and the outer sheath 32 are formed, the inner sheath portion 31 that is short by the protrusion 7 is integrated with the outer sheath 32 on the outer side.

  In this example, the projection 7 embedded in the outer sheath 32 is used to integrate the outer sheath 32 and the short inner jacket portion 31A divided by the pair of string-like separators 5. The outer sheath 32 and the short inner jacket portion 31A may be integrated using other means capable of integrating the sheath 32 and the shorter inner jacket portion 31A.

  As other means in this case, integration using an adhesive resin, fusion of the outer sheath 32 to be joined and the short inner jacket portion 31A, or the like can be used. In order to firmly fix, it is desirable to adopt a structure in which the protrusion 7 is buried.

  As described above, this embodiment includes an integration unit that integrates a short inner jacket portion into the low-density polyethylene outer sheath 31.

  FIG. 2 shows a method for tearing the optical fiber cable 100 and a method for drawing the optical fiber core wire from the optical fiber cable 100.

  In FIG. 2, as shown in FIG. 2A, the left and right sides of the outer sheath 32 are torn with a cutter knife (not shown) that is normally used for tearing. In the case of this example, it is torn at the arrangement positions of the tension members 4 arranged on the left and right sides. This vicinity or another place may be sufficient. In this case, the tip of the cutter knife contacts the inner sheath 31, but the inner sheath is made of high-density ethylene so that it does not tear up to the inner sheath 31.

  As shown in FIG. 2B, the outer sheath 32 is separated into an upper outer sheath 32 </ b> A and a lower outer sheath portion 32 </ b> B, and the upper outer sheath portion 32 </ b> A is pulled away from the inner sheath 31. In this state, the tension member 4 is held by the inner sheath 31.

  When the upper outer sheath portion 32A is pulled away from the inner sheath 31, the short inner jacket portion 31A is integrated with the upper outer sheath portion 32A via the projection 7, so that a pair of string-like separators 5 is attached. It is separated from the long inner casing portion 31B as a boundary. That is, the upper outer sheath portion 32A and the short inner jacket portion 31A are simultaneously separated in one process by one operation of separating the upper outer sheath portion 32A. At the same time, the separator 5 is separated from the inner sheath 31.

  Along with the separation of the short inner jacket portion 31A, a space 33 is formed at the trace of the short inner jacket portion 31A. That is, the space portion 33 is simultaneously formed in one step by the separation operation of the upper outer sheath portion 32A from the inner sheath 31.

  Next, as shown in FIG. 2C, when the upper outer sheath portion 32A, the short inner jacket portion 31A, and the pair of string-like separators are removed, the space portion 33 is opened outward. This space portion 33 is used as a space for taking out the optical fiber cable 100, that is, the optical fiber core wire from the cylindrical body 1.

  The inner sheath 31 includes a pair of string-like separators 5 that are substantially entirely embedded in the inner sheath in the longitudinal direction, and a portion 5A on the outer side reaches the outer sheath 32, and the outer sheath 32 Since the projection 7 for integrating the short inner jacket portion 31A is provided, the inner sheath is easily made of high-density polyethylene, and the space portion 33 is formed.

  Thus, the space part 33 is formed, and the optical fiber core housed here is easily taken out from the cable core housing region.

  The inner sheath 31 is provided with a pair of string-like separators 5 that are almost entirely buried in the inner sheath in the longitudinal direction and a part of the outer outer side reaches 5 A into the outer sheath 32. Therefore, the inner sheath 31 is easily torn while being made of high-density polyethylene, and the space portion 33 is formed in the trace of the short inner jacket portion 31. It is not easy to cut the inner sheath 31 with a cutter knife, and there is a risk of damaging the cylindrical body 1 or the optical fiber core housed therein. However, a pair of string-like separators 5 is incorporated in the inner sheath 31 in advance. If the space portion 33 is easily formed in a region partitioned by the pair of string-like separators 5 in advance, the cylindrical body 1 or the optical fiber core wire is not damaged. Further, in the configuration in which the string is provided in the cable core 1, there is a risk of damaging the cylindrical body 1 or the optical fiber core wire, but according to the present embodiment, there is no risk of damaging. And since the area | region of the space part 33 can be determined in the setting place of a set of string-like separator 5, the area | region of a space can be set easily arbitrarily.

  As described above, when this structure is adopted, a slotless structure is used, but if a C slot is present, the same usage is possible.

  Further, this structure can provide a combination of a high-density polyethylene sheath and a low-density polyethylene sheath with a two-layer sheath, thereby providing a highly compressible and flexible optical fiber cable.

  In addition, since the inner sheath discarded when the optical fiber core wire is taken out has a length determined by the width region of the pair of string-like separators 5, the environment is considered by shortening this length. Enable work. In this operation, a part of the inner sheath can be easily cut as described above, and the workability can be improved.

  In this example, the work is performed in the order of (a) → (b) → (c), but the structure shown in FIG. 2 (d) is adopted and (d) → (b) → (c). You may make it work according to the order.

  FIG. 2D shows an optical fiber cable 100 in which notches 6 are formed in the outer sheath 32 at target positions on both the left and right sides.

  By forming such a notch 6, it is possible to cut the outer sheath 32 into upper and lower parts without using a cutter knife required in the case of FIG. If the notch 6 is formed in the outer sheath 32 in this way, it becomes easy to tear.

  The example shown in FIG. 2 includes the following steps.

A step of tearing the outer sheath 32 to separate it into two parts and exposing the pair of string-like separators 5 from the inner sheath 31. By pulling the string 5, the short inner and outer sides between the pair of string-like separators A step of separating the covering portion 31A from the long inner covering portion 31B and forming a space portion 33 for taking out the optical fiber core wire at the trace of the separated short inner covering portion 31B; The step of taking out the optical fiber core in the body 1 to the outside The method for tearing the optical fiber cable and the method for taking out the optical fiber core are formed as described above.

  According to this embodiment, a set of high-density polyethylene inner sheaths are substantially entirely embedded longitudinally within the high-density polyethylene inner sheath and a portion of the outer outside reaches the low-density polyethylene outer sheath. Since it has a configuration including a string-like separator, when a low-density polyethylene outer sheath is torn, a pair of high-density polyethylene inner sheaths are provided with a pair of string-like separators, so that a part of the high-density polyethylene inner sheath is partially attached. By tearing at the same time in the process, the tearing workability can be improved.

  Further, according to this embodiment, when the high-density polyethylene inner sheath is torn, it is possible to form a space having an arbitrary length determined by the length of the string width of the pair of string-shaped separators, and torn the work. Improve sex more. The high-density polyethylene inner sheath that is discarded by setting this space width to the minimum width required for work can be the minimum length required for work, and it is an optical fiber cable that is environmentally friendly and has good disposal properties. be able to.

  DESCRIPTION OF SYMBOLS 1 ... Cylindrical body, 2 ... Cable core, 3 ... Sheath, 4 ... Tension member, 5 ... String-like separator (one set of string-like separator), 7 ... Protrusion, 31 ... High density polyethylene inner sheath (inner sheath) 32 ... Low density polyethylene outer sheath (outer sheath), 31A ... Short inner jacket part, 31B ... Long inner jacket part, 33 ... Space part, 100 ... Optical fiber cable.

Claims (6)

An optical fiber cable having a cable core formed of a filler disposed around a cylindrical body in which a plurality of optical fiber cores are housed, and having a sheath outside a cable core housing region for housing the formed cable core In
The sheath is formed of two layers of a high hardness inner sheath provided around the cable core and a low hardness outer sheath provided around the high hardness inner sheath;
A tension member, which is a tensile member, is embedded in the longitudinal direction inside the low hardness outer sheath, the high hardness inner sheath or between the low hardness outer sheath and the high hardness inner sheath,
The high-hardness inner sheath is disposed in the high-hardness inner sheath, and a part of the inner side in the longitudinal direction is disposed close to the cable core storage region, and a part of the outer side is the outer part having the low hardness. A set of string-like separators embedded so as to reach the sheath,
The pair of string-shaped separators divides the high hardness inner sheath into a short inner jacket part and a long inner jacket part,
An optical fiber cable comprising an integration means for integrating the short inner jacket portion with the low density polyethylene outer sheath. An optical fiber cable having a cable core formed of a filler disposed around a cylindrical body in which a plurality of optical fiber cores are housed, and having a sheath outside a cable core housing region for housing the formed cable core In
The sheath is formed of two layers, a high density polyethylene inner sheath provided around the cable core and a low density polyethylene outer sheath provided around the high density polyethylene inner sheath,
A tension member, which is a tensile member, is embedded in the longitudinal direction inside the low density polyethylene outer sheath, inside the high density polyethylene inner sheath or between the low density polyethylene outer sheath and the high density polyethylene inner sheath,
The high-density polyethylene inner sheath is disposed within the high-density polyethylene inner sheath and a part of the inner side in the longitudinal direction is close to the cable core storage region, and a part of the outer side is the outer part of the low-density polyethylene. A set of string-like separators embedded so as to reach the sheath,
The pair of string-like separators divides the high-density polyethylene inner sheath into a short inner jacket portion and a long inner jacket portion;
An optical fiber cable comprising an integration means for integrating the short inner jacket portion with the low density polyethylene outer sheath.   3. The optical fiber cable according to claim 1, wherein a part of the inner side of the string-shaped separator is in contact with the cable core storage region. 3. The optical fiber cable according to claim 2, wherein the integration means is a protrusion integrated with the low-density polyethylene outer sheath by being embedded in the low-density polyethylene outer sheath facing outward. .   5. The optical fiber cable according to claim 4, wherein the protrusion forms an inverted trapezoidal wedge shape. The method for tearing an optical fiber cable according to claim 4 or 5,
The low-density polyethylene outer sheath is split into two parts by tearing, and the low-density polyethylene outer sheath on the side where the protrusions are buried is pulled, so that a short inner jacket portion between the pair of separators is formed. From an optical fiber cable characterized in that when a short inner jacket part separated and removed from a long inner jacket part is removed, an extraction space part for taking out the optical fiber core wire is formed. An optical fiber tearing method.

Images