JP5468946B2 - Fiber optic cable - Google Patents

Description

  The present invention relates to an optical fiber cable or the like excellent in laying workability.

  Conventionally, an optical fiber cable in which an optical fiber core wire is covered with a jacket is used. At the time of use, such an optical fiber cable is branched and arranged into a plurality of houses.

  As such an optical fiber cable, for example, there is an optical fiber cable in which an optical fiber core wire and a tension member are integrally covered and a notch is formed in a covering portion (Patent Document 1).

  Also, there is a collective optical fiber cable in which optical fiber cores and strength members are arranged in a straight line and a plurality of elements collectively covered with a jacket are linearly connected by a connecting portion (Patent Document 2). ).

Japanese Patent Laid-Open No. 2004-12832 JP 2008-70573 A

  However, the optical fiber cable of Patent Document 1 has a problem in that the installation workability is poor because it is necessary to lay the same number of cables in each of a plurality of houses. In particular, when laying multiple optical fiber cables, it is necessary to insert the optical fiber cable through a protective tube, but the rigidity of the optical fiber cable itself is low. When the optical fiber cable is inserted, there is a problem that the insertion operation is difficult due to bending of the optical fiber cable.

  In addition, the optical fiber cable of Patent Document 2 has a plurality of elements arranged in a straight line, and many optical fibers can be laid at a time. However, since the elements are arranged in a straight line, In the case of insertion, the protective tube cannot be efficiently inserted into the protective tube, and a protective tube having a size corresponding to the circumscribed circle of the collective optical fiber cable is required. For this reason, there exists a problem that there are few laying efficiency and installation freedom.

  Moreover, since the optical fiber cable of patent document 2 needs to arrange | position the tear string for cut | disconnecting a connection part, there exists a problem that manufacturability is bad and cost and a manufacturing man-hour are required. Further, if the tear string breaks, it is very difficult to separate the elements, and there is a risk of damaging the inner optical core when cutting with a cutter or the like.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical fiber cable or the like that is excellent in laying workability and excellent in installation efficiency.

In order to achieve the above-described object, the present invention includes a plurality of optical fiber elements each having an optical fiber core wire and having an outer periphery coated with a covering portion, and a connecting portion that connects the optical fiber elements to each other. comprising, the connecting portion by bending, can be folded to the optical fiber element adjacent coupled der is, crest curved or bent at a substantially central portion of the connecting portion is formed, the It is an optical fiber cable characterized in that the height of the crest is 0.2 mm or more and 5 mm or less .

  Here, it is possible to fold adjacent optical fiber elements connected together, from the state in which the optical fiber elements are linearly arranged, the adjacent optical fiber elements are at an angle of approximately 180 degrees. It means that it can be bent.

  The connecting portion is preferably provided at a height h from the lower end of the optical fiber element in the cross section of the optical fiber element, and the length L of the connecting portion is preferably L ≧ 2h + 0.2 mm.

  Here, the lower end of the optical fiber element is a portion (a portion corresponding to a surface in the vertical direction) that faces in a direction perpendicular to the direction in which the connecting portion is provided in the cross section of the optical fiber element. The end near the side. The height h from the lower end means the distance from the lower end to the lower surface of the connecting portion.

  Here, the peak portion means a convex portion that goes upward when the lower end described above is directed downward.

  The thickness of the substantially central portion of the connecting portion may be not less than 0.1 mm and not more than 0.8 mm. A concave portion thinner than the thickness of the base portion of the connecting portion may be formed in a substantially central portion of the connecting portion.

  The optical fiber element has a substantially rectangular shape, and in the cross section of the optical fiber element, the optical fiber core wire is formed substantially at the center of the optical fiber element, and tension members are provided on both sides of the optical fiber core wire. The optical fiber elements may be coupled such that the tension members of the adjacent optical fiber elements are arranged in parallel in the coupling direction.

  It is desirable that the connecting portion has a tensile elastic modulus of 650 MPa or less.

According to the present invention, a plurality of optical fiber elements are connected by a connecting portion, and it is possible to fold adjacent optical fiber elements by bending them at the connecting portion. It can be a cross-sectional form and can be inserted into a more compact protective tube or the like.

  Further, since the connecting portion can be exposed by folding a plurality of optical fiber elements, there is no need to provide a special tear string or the like, and it can be easily and safely cut with a nipper or the like.

  Further, since the connecting portion is provided at a position of height h from the lower end of the optical fiber element in the cross section of the optical fiber element, and the length L of the connecting portion is L ≧ 2h + 0.2 mm, the height of the connecting portion If the length of the connecting portion is changed according to the above, the connecting portion can be formed at an arbitrary portion, and even in this case, the optical fiber element can be reliably folded.

  Further, if a bent or bent peak portion is formed at the substantially central portion of the connecting portion, it becomes easy to bend the connecting portion. In this case, if the height of the peak portion is 0.2 mm or more, the effect is obtained. Is big.

  Moreover, if the thickness of the substantially center part of a connection part is 0.1 mm or more and 0.8 mm or less, while being able to connect optical fiber elements reliably, the cutting | disconnection of a connection part is easy.

  Moreover, if the recessed part thinner than the thickness of the base part of a connection part is formed in the approximate center part of a connection part, it will become further easier to bend and cut | disconnect a connection part.

  Also, in the cross section of the optical fiber element, tension members are provided on both sides of the optical fiber core, and when the optical fiber elements are connected and arranged in a straight line, the tension members are arranged in parallel in the connecting direction. Thus, when the optical fiber cable is wound around the bobbin or the like, stress such as tension is not generated in the tension member due to the difference in winding thickness.

  Further, if the tensile modulus of the connecting portion is 650 MPa or less, the connecting portion can be easily deformed, and therefore the connecting portion can be easily bent.

  ADVANTAGE OF THE INVENTION According to this invention, the optical fiber cable etc. which are excellent in laying workability | operativity and excellent in installation efficiency can be provided.

It is sectional drawing of the optical fiber cable 1, (a) is a state before folding an optical fiber element, (b) is a figure which shows the state which folded the optical fiber element. FIG. 2 is an enlarged view of a portion A in FIG. It is a figure which shows the isolation | separation method of optical fiber elements, (a) is the B section enlarged view of FIG.1 (b), (b) is a figure which shows the state by which optical fiber elements were isolate | separated. (A) is sectional drawing of the optical fiber cable 1a, (b) is the E section enlarged view of (a). (A) is sectional drawing of the optical fiber cable 1b, (b) is the F section enlarged view of (a), and is a figure which shows the recessed part 17a, (c) is a figure which shows the recessed part 17b similarly to (b). (A) is sectional drawing of the optical fiber cable 20a, (b) is sectional drawing of the optical fiber cable 20b. Sectional drawing which shows the state which folded the optical fiber cable. The figure which shows the state which penetrates the optical fiber cable 30 of the folded state to the duct 31. FIG. 2 is a cross-sectional view showing an optical fiber cable 40. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an optical fiber cable 1, FIG. 1 (a) is a view showing a state before the optical fiber element is folded, and FIG. 1 (b) is a view showing a state in which the optical fiber element is folded. . The optical fiber cable 1 includes an optical fiber element 3, a connecting portion 11, and the like.

  The optical fiber element 3 is formed such that the optical fiber core wire 5 and the tension member 7 are housed inside and the outside is covered with a covering portion 9. The optical fiber core wire 5 may be a single core fiber, a unit in which single fiber fibers are bundled, or the like, or may be a tape core wire in which a plurality of single fiber cores are lined up and covered.

  The tension member 7 is a part responsible for the tension of the optical fiber cable, and is formed on both sides of the optical fiber core wire 5. As the tension member 7, for example, a fiber reinforced plastic made of steel wire, aramid fiber or the like can be used. The covering portion 9 integrally covers the optical fiber core wire 5 and the tension member 7.

  The optical fiber element 3 (covering portion 9) has a substantially rectangular cross-sectional shape, and a plurality (two in the figure) of optical fiber elements 3 are provided side by side. As the optical fiber element 3, for example, an optical fiber core wire 5 having an outer diameter of 0.25 mm is provided inside, and tension members 7 made of fiber reinforced plastic made of aramid fiber having an outer diameter of 0.5 mm are provided on both sides. It is a thing.

  The side surfaces of the optical fiber element 3 are connected by a connecting portion 11. The optical fiber element 3 has a notch or the like formed on the outer peripheral portion (upper and lower surface direction in the drawing) as necessary. The connecting portion 11 may be the same resin as the covering portion 9 or may be a different resin. Further, the connecting portion 11 may be formed integrally with the covering portion 9 or may be formed separately from the covering portion 9.

  Examples of the covering portion 9 and the connecting portion 11 include polyethylene, linear low-density polyethylene, ethylene / α-olefin copolymer, polypropylene, propylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, and ethylene.・ Polyacrylate resins such as acrylic acid ester copolymers, ethylene / methacrylic acid ester copolymers, ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, ethylene / ethyl acrylate copolymers, ionomers, polyamides , Polyurethane, polyester, polystyrene, polyvinyl chloride and other thermoplastic resins, thermoplastic resin elastomers, styrene butadiene rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, ethylene propylene terpolymer Synthetic rubbers such as butyl rubber, acrylic rubber, and silicone rubber can be used.

  Further, an acid-modified product obtained by modifying the above-described thermoplastic resin with an unsaturated carboxylic acid and / or a derivative thereof can be used. One of these synthetic resins may be used alone, or two or more of these synthetic resins may be used in combination as a resin composition.

  It should be noted that various resin components and various additives other than those described above can be appropriately added to the covering portion 9 and the connecting portion 11 as necessary within a range that does not hinder the object and effect of the present invention. As the additive, conventionally known ones can be used. For example, flame retardants, lubricants, modifiers, antioxidants, light stabilizers composed of metal hydrates such as magnesium hydroxide and aluminum hydroxide. , Process oil, silicone oil, UV absorber, carbon black, dispersant, pigment, dye, anti-blocking agent, crosslinking agent, crosslinking aid, etc. In addition, flame retardant aids such as polyphosphate compounds, zinc hydroxystannate, zinc stannate, zinc borate, calcium carbonate, hydrotalcite, and antimony oxide may be added.

  Moreover, as resin which comprises the connection part 11, it is desirable for a tensile elasticity modulus to be 650 Mpa or less. This is because when the tensile modulus of the connecting portion 11 exceeds 650 MPa, the bending operation of the connecting portion 11 becomes difficult. In addition, about the tensile elasticity modulus of a connection part, you may make it obtain desired tensile elasticity modulus by using one type of synthetic resin whose tensile elasticity modulus after shaping | molding is known. A desired tensile elastic modulus may be obtained by using a combination of resins, or a combination of different resins of the same type.

  As shown in FIG. 1A, in a state where the optical fiber element 3 is connected by the connecting portion 11 and the optical fiber element 3 is installed so as to be arranged in a straight line, the tension member 7 is connected in a substantially straight line. Arranged in parallel in the direction.

  As shown in FIG. 1B, the optical fiber cable 1 can be bent at the connecting portion 11, and the optical fiber element 3 can be folded by bending the connecting portion 11 (in the direction of arrow C in the figure). ). That is, the optical fiber elements 3 can be bent so as to rotate approximately 180 degrees.

  The cross-sectional shape of the optical fiber cable 1 can be changed by folding the optical fiber elements 3 together. In the example of FIG. 1, light is applied in the short side direction of the optical fiber element 3 from the horizontally long state (the state of FIG. 1A) in which the optical fiber elements 3 are arranged in parallel in the long side direction of the optical fiber element 3. It can be changed to a vertically long state (or a rectangular shape close to a square) arranged so that the fiber elements 3 are arranged in parallel (the state shown in FIG. 1B).

  In addition, in the state of FIG.1 (b), the connection part 11 is exposed to the side of the optical fiber cable 1. FIG.

  FIG. 2 is an enlarged cross-sectional view of the connecting portion 11, and is an enlarged view of a portion A in FIG. The arrangement and shape of the connecting portion 11 are defined as follows. The length L of the connection part 11 points out the distance of the side surfaces of adjacent optical fiber elements 3 (covering part 9). In this case, as shown in FIG. 2, when the positions of the connecting portions between the upper and lower surfaces of the connecting portion 11 and the covering portion 9 are different, the distance between the connecting portions of the connecting portion 11 and the covering portion 9 is shorter ( The length in the upper part in the figure is L.

  The thickness t of the connecting portion 11 refers to the thickness of the connecting portion 11 at the substantially central portion of the connecting portion 11. The arrangement height h of the connecting portion 11 refers to the length from the lower end (lower surface) of the covering portion 9 to the lower end (lower surface) of the connecting portion 11. Note that the lower end of the covering portion 9 is a connecting portion 11 in a surface (upper and lower surfaces in the example of FIG. 1) in a direction (vertical direction in the drawing) perpendicular to the connecting direction of the connecting portion 11 (left and right in the drawing). This refers to the surface (the lower surface in the example of FIG. 1) on the side close to. Therefore, in the state shown in FIG. 1A, in the state where the optical fiber cable 1 is placed on the ground or the like, the distance from the ground to the lower surface of the connecting portion 11 is h. Further, when the lower surface of the connecting portion 11 and the lower surface of the covering portion 9 coincide with each other, h is 0.

  As the connection part 11 of this invention, it is desirable that it is L (mm)> = 2h (mm) + 0.2mm. If L is 0.2 mm or longer with respect to 2h, the connecting portion 11 can be easily deformed by 180 degrees, and the optical fiber elements 3 can be reliably folded. At L = 2h, when the connecting portion is bent 180 degrees, the connecting portion is pulled and deformation becomes difficult.

  Further, t of the connecting portion 11 is desirably 0.1 mm or more and 0.8 mm or less. This is because if t is less than 0.1 mm, it may be easily broken during production or laying. Moreover, it is because it will become difficult to bend and cut | disconnect the connection part 11 if it exceeds 0.8 mm.

  Next, a method for separating the optical fiber elements 3 will be described. 3A and 3B are diagrams illustrating a method of separating the optical fiber element 3, FIG. 3A is an enlarged view of a portion B in FIG. 1B, and FIG. 3B is a state in which the optical fiber element 3 is separated. FIG.

  As described above, in a state where the connecting portion 11 is bent and the optical fiber elements 3 are folded, the bent connecting portion 11 is exposed to the side of the optical fiber cable 1. In this state, the connecting part 11 is cut by the cutting part 13.

  In this state, the optical fiber elements 3 are separated from each other in the separation direction (D direction in the figure), whereby the separation of the optical fiber elements 3 is completed and a branching portion is formed. The separated optical fiber element is partially cut in the axial direction and is connected to an optical fiber cable or the like in the branch direction by a separate connector or the like.

  As described above, according to the present invention, since the optical fiber elements 3 can be folded by bending the connecting portion 11, it is easy to cut the connecting portion 11. For this reason, the separation work of the optical fiber element 3 is easy. Moreover, the cross-sectional shape of the optical fiber cable 1 can be changed by folding the optical fiber element. For this reason, the cross section of the optical fiber cable 1 can be changed according to the shape of the installation place, and the installation workability of the optical fiber cable 1 is excellent.

  Next, another embodiment will be described. 4A and 4B are diagrams illustrating the optical fiber cable 1a, in which FIG. 4A is an overall cross-sectional view, and FIG. 4B is an enlarged view of a portion E in FIG. Note that in the following embodiments, the same functions as those of the optical fiber cable 1 are denoted by the same reference numerals as those in FIG. The optical fiber cable 1a has substantially the same configuration as the optical fiber cable 1, but differs in that a connecting portion 11a having a peak portion 15 is provided.

  As shown in FIG. 4B, a peak portion 15 that is curved (or bent) in a convex shape upward is formed at the approximate center of the connecting portion 11a. Here, “upper” refers to the upper side when the reference portion for the height h of the connecting portion 11a is set as the lower side. That is, it is convex in the surface direction on the side where the connecting portion is exposed in the folded state.

  In connection part 11a, height d of peak part 15 is the height to the lower surface of peak part 15 (substantially central position of connection part 11a) on the basis of the connection part of the undersurface of connection part 11a, and covering part 9. Point to. The height d of the crest 15 is preferably 0.2 mm or more and 5 mm or less. It becomes possible to bend the connection part 11 more easily because d shall be 0.2 mm or more. Moreover, it is because there exists a possibility that the inner sides of a peak part may weld when d exceeds 5 mm.

  According to the optical fiber cable 1a, the same effect as that of the optical fiber cable 1 can be obtained. Moreover, since the connection part 11a is easy to bend, the optical fiber element 3 can be easily folded.

  5A and 5B are diagrams showing an optical fiber cable 1b according to still another embodiment. FIG. 5A is an overall cross-sectional view, and FIGS. 5B and 5C are F in FIG. FIG. The optical fiber cable 1b has substantially the same configuration as the optical fiber cable 1, but differs in that a connecting portion 11b having a recess 17a is provided.

  The concave portion 17a is formed at a substantially central portion of the connecting portion 11b, and the connecting portion 11b is thinner than other portions. In addition, the recessed part 17a may be provided in both surfaces of the connection part 11b, and may be provided only in one surface. Here, the thickness t of the connecting portion 11b indicates the thickness at the position of the concave portion 17a.

  Further, as shown in FIG. 5B, the shape of the recess may be a recess provided only in the substantially central portion of the connecting portion 11a. As shown in the recess 17b shown in FIG. You may form in the whole part 11b. In any case, it may be formed so as to have the smallest thickness in the substantially central portion of the connecting portion 11b. Moreover, the cross-sectional shape of a recessed part can employ | adopt various forms, such as not only U shape but V shape.

  According to the optical fiber cable 1b, the same effect as the optical fiber cable 1 can be obtained. Moreover, since a recessed part is formed in the center part of the connection part 11b and becomes thin, the optical fiber element 3 is easy to fold and cut | disconnect.

  Next, another embodiment will be described with respect to a connection mode between optical fiber elements. As shown in FIG. 6A, an optical fiber cable 20a in which three (or more) optical fiber elements 3 are connected by a connecting portion 11 may be used. Further, in this case, as shown in FIG. 6B, the connecting portions 11 need not be formed at a fixed height in the connecting portions, and the connecting portions 11 may be provided at different positions. In the example of FIG. 6B, the height h of the connecting portion 11 between the optical fiber element 3 on the left side and the central optical fiber element 3 in the drawing is obtained on the basis of the lower surface in the drawing, and the light on the right side in the drawing The connecting portion 11 between the fiber element 3 and the central optical fiber element 3 is required to have a height h with reference to the upper surface in the drawing.

  FIG. 7 is a diagram illustrating a state in which the optical fiber cable 30 in which the four optical fiber elements 3 are connected to each other at different connecting portions 11 in the vertical direction is folded. As shown in FIG. 7, each optical fiber element 3 can be folded at 180 degrees or 90 degrees. Note that the method of folding the optical fiber cable 30 is not limited to the example shown in FIG. 7, and the optical fiber cable 30 can be folded into an arbitrary shape. Furthermore, various modifications can be handled by changing the number of optical fiber elements and the arrangement of the connecting portions 11.

  FIG. 8 is a diagram illustrating a state in which the optical fiber cable 30 is inserted into the duct 31 that is a protective tube. As shown in FIG. 7, by holding the cross-sectional shape of the optical fiber cable 30 with the band 33 as a holding member in a state where the optical fiber element 3 is folded, the rigidity in the vertical direction or the horizontal direction of the optical fiber cable 30 is increased. Can be raised. For this reason, the optical fiber cable 30 is not bent during insertion into the duct 31. Even when an existing optical fiber cable is laid inside the duct 31, the optical fiber cable 30 can be more efficiently inserted into the duct 31 if the optical fiber element is folded according to the cross-sectional shape of the installation space. Can do. An adhesive member such as a tape may be used instead of the band.

  Needless to say, the various embodiments described above can be combined with each other. Further, the optical fiber cable may be not only an optical fiber element having a substantially rectangular cross section but also an optical fiber element having a circular cross section.

  For example, an optical fiber cable 40 including an optical fiber element 41 having a substantially circular cross section as shown in FIG. 9 may be used. The optical fiber cable 40 has a substantially circular cross-section optical fiber element 41 connected by a connecting portion 11 such that an optical fiber core wire 5 is provided at a substantially center and a tension member 7 is formed around the optical fiber core wire 5. In this case, in a state where the connecting portion 11 is not bent (the state shown in FIG. 9), an intersection point (that is, the lowermost end in the drawing) with a tangent line below the adjacent optical fiber element 41 (the side where the connecting portion 11 is provided) What is necessary is just to make it the reference point of the height h of the connection part 11. FIG.

  Using various types of optical fiber cables having a connecting portion, the ease of folding and the ease of cutting were evaluated. The results are shown in Table 1.

  The optical fiber cable used for the evaluation has an optical fiber element having a substantially rectangular cross section as shown in FIG. “Element height A” refers to the height of the optical fiber cable (optical fiber element) (the total height in FIG. 1). “Element width B” refers to the total width of the optical fiber element. The “connection portion length L” is the length of the connection portion and corresponds to L in FIG. The “connection portion height h” is the height from the reference (the lower end of the covering portion) of the connection portion, and corresponds to h in FIG.

  The “connection portion thickness t” is a thickness at a substantially central portion of the connection portion, and corresponds to t in FIG. The “mountain height d” is the height of the mountain portion and corresponds to d in FIG. Note that the peak height d of 0 indicates that the connecting part does not have a peak.

  “Tensile elastic modulus” indicates the tensile elastic modulus of the resin constituting the connecting portion. “Deformation” indicates the ease of deformation, “◯” indicates that the deformation of about 180 degrees was easy as shown in FIG. 1B, and “Deformation” indicates that the deformation is possible but not easy. “Δ”, and those that could not be deformed were “x”. As for “cutting”, the connecting portion after deformation was easily cut as shown in FIG. 3A and “◯” was given, and “×” was difficult to cut.

  In Comparative Example 1, as in Patent Document 2, a connecting portion is provided at the approximate height center of the optical fiber element, and the length of the connecting portion is substantially equal to the height of the connecting portion (L = 1.1h). Could not be deformed.

  In Example 1, the height of the connecting portion is 0 (the lower surface of the connecting portion is coincident with the lower surface of the optical fiber element), and L = 1 ≧ 2h + 0.2, so that it can be easily deformed, Cutting was also possible.

  In Example 2, since L = 2h with respect to the connection portion height h, L ≧ 2h + 0.2 was not satisfied, and thus deformation was not easy. For this reason, cutting could not be performed.

  In Example 3, the height of the connecting portion was the same as that in Example 2, but L ≧ 2h + 0.2 was satisfied, so deformation was easy and cutting was possible.

  In Example 4, the height h of the connecting portion was set to 0.7, but L = 2h, so L ≧ 2h + 0.2 was not satisfied, and thus deformation was not easy. For this reason, cutting could not be performed.

  Example 5 and the height of the connecting portion were the same as those of Example 4, but because L ≧ 2h + 0.2 was satisfied, deformation was easy and cutting was possible.

  In Example 6, the connecting portion thickness was 0.8 mm, which was thicker than those in Examples 1 to 5. However, since L ≧ 2h + 0.2 was satisfied, deformation was easy and cutting was possible. However, at a tensile modulus of 980 MPa, the strength of the connecting portion was too high, so that deformation was not easy.

  In Example 7, although L ≧ 2h + 0.2 is satisfied, since the connecting portion thickness is as large as 1.0 mm, the deformation is not easy, and when the tensile elastic modulus is 980 MPa, the strength of the connecting portion is too high. I did not let it.

  In Example 8, the thickness of the connecting portion was as large as 1.0 mm as in Example 7, but it was easily deformed because it had a mountain portion (height 0.2 mm). By forming the mountain portion, the deformation becomes easier. However, at a tensile elastic modulus of 980 MPa, the strength of the connecting portion was too high, so that it was not deformed.

  In Example 9, since L = 2h, L ≧ 2h + 0.2 was not satisfied, but since it had a peak portion (height 0.2 mm), deformation was easy.

  In Example 10, L = 2h as in Example 9, and therefore L ≧ 2h + 0.2 was not satisfied, but because it had a peak (height 0.2 mm), it was easily deformed.

  As described above, if L ≧ 2h + 0.2 is satisfied, deformation and cutting are facilitated. Further, when the thickness of the connecting portion exceeds 0.8 mm, the deformation is not easy. However, if the peak portion is provided by 0.2 mm or more, the deformation becomes easier, so that the allowable range of the value of L with respect to h and the value of the thickness t of the connecting portion can be expanded. In addition, although d is only an example of 0.2 mm, it cannot be overemphasized that it can deform | transform more easily if it is 0.2 mm or more. Although detailed description is omitted, the same results as those shown in Table 1 were obtained for the optical fiber cable shown in FIG.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

1, 1a, 1b, 20a, 20b, 30, 40 ... Optical fiber cable 3, 41 ... Optical fiber element 5 Optical fiber core 7 Tension member 9 Coated part 11, 11a, 11b ......... connecting portion 13 ......... cutting portion 15 ......... mountain portions 17a, 17b ......... concave portion 31 ......... duct 33 ......... band

Claims (6)

A plurality of optical fiber elements each having an optical fiber core wire and having an outer periphery coated with a covering portion;
A connecting portion for connecting the optical fiber elements;
Comprising
By bending the coupling portion, Ri can der folding the said optical fiber element adjacent coupled,
An optical fiber cable characterized in that a curved or bent peak part is formed at a substantially central part of the connecting part, and the height of the peak part is 0.2 mm or more and 5 mm or less . The connecting portion is provided at a position of a height h from a lower end of the optical fiber element in the cross section of the optical fiber element.
2. The optical fiber cable according to claim 1, wherein a length L of the connecting portion is L ≧ 2h + 0.2 mm. The optical fiber cable according to claim 1 or 2, wherein a thickness of a substantially central portion of the connecting portion is 0.1 mm or more and 0.8 mm or less. The optical fiber cable according to any one of claims 1 to 3 , wherein a concave portion thinner than a thickness of a base portion of the connecting portion is formed in a substantially central portion of the connecting portion. The optical fiber element has a substantially rectangular shape, and in the cross section of the optical fiber element, the optical fiber core wire is formed substantially at the center of the optical fiber element, and tension members are provided on both sides of the optical fiber core wire. The optical fiber according to any one of claims 1 to 4 , wherein the optical fiber elements are connected such that the tension members of the adjacent optical fiber elements are arranged in parallel in the connecting direction. cable. The optical fiber cable according to any one of claims 1 to 5 , wherein a tensile elastic modulus of the connecting portion is 650 MPa or less.

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