Optical fiber cable and method for manufacturing optical fiber cable

Abstract

An optical fiber cable (1A) comprises: a core (10) that has optical fibers (11); a restricting member (20) that is longitudinally attached to the core (10) and covers the core (10); a sheath (40) that covers the restricting member (20); and a ripcord (60) that is positioned between the sheath (40) and the core (10), wherein the ripcord (60) is positioned between a first part (21) and a second part (22) of the restricting member (20).

Description

Technical Field

[0001] The present invention relates to an optical fiber cable and a method for manufacturing an optical fiber cable. This application claims priority based on Japanese Patent Application No. 2022-039603 filed in Japan on March 14, 2022, and incorporates the content herein by reference.

Background Art

[0002] Patent Document 1 discloses an optical fiber cable in which a lip cord for tearing an outer sheath is disposed in a space provided inside the outer sheath.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the structure disclosed in Patent Document 1, there is a problem that the lip cord is likely to move in the circumferential direction in the space provided inside the outer sheath. When the lip cord moves, it becomes difficult to perform the tearing operation of the outer sheath.

[0005] The present invention has been made in consideration of such circumstances, and an object thereof is to provide an optical fiber cable and a method for manufacturing an optical fiber cable capable of suppressing the movement of the lip cord.

Means for Solving the Problems

[0006] To solve the above problems, an optical fiber cable according to a first aspect of the present invention comprises a core having an optical fiber, a regulating member longitudinally attached to the core and covering the core, a sheath covering the regulating member, and a rip cord located between the sheath and the core, wherein the rip cord is located between a first part and a second part of the regulating member. A method for manufacturing an optical fiber cable according to a second aspect of the present invention comprises: a first step of preparing a core having an optical fiber; a second step of winding a restricting member around the core; a third step of covering the core having the restricting member with a reinforcing member; and a fourth step of covering the reinforcing member with a sheath, wherein in the second step, the restricting member is bent and a rip cord is placed inside the folded portion of the restricting member. [Effects of the Invention]

[0007] According to the above embodiment of the present invention, it is possible to provide an optical fiber cable capable of suppressing the movement of the rip cord. [Brief explanation of the drawing]

[0008] [Figure 1] This is an example of a cross-sectional view of an optical fiber cable according to the first embodiment. [Figure 2] This is an example of a cross-sectional view of an optical fiber cable according to the second embodiment. [Figure 3] This is an example of a cross-sectional view of an optical fiber cable according to the third embodiment. [Figure 4] This is an example of a cross-sectional view of an optical fiber cable according to the fourth embodiment. [Figure 5] This is an example of a cross-sectional view of an optical fiber cable according to a modified example of the fourth embodiment. [Figure 6] This is an example of a cross-sectional view of an optical fiber cable according to the fifth embodiment. [Modes for carrying out the invention]

[0009] (First Embodiment) The configuration of the optical fiber cable according to the first embodiment will be described below with reference to Figure 1. As shown in Figure 1, the optical fiber cable 1A comprises a core 10 having an optical fiber 11, a regulating member 20 covering the core 10, a reinforcing member 30, a sheath 40, four tensile strength members 50, and two rip cords 60.

[0010] In this embodiment, the longitudinal direction of the core 10 is simply referred to as the longitudinal direction, and the central axis of the core 10 is simply referred to as the central axis O. A cross-section perpendicular to the central axis O is called a cross-section. In a cross-sectional view, the direction intersecting the central axis O is called the radial direction, and the direction circumferential around the central axis O is called the circumferential direction.

[0011] The core 10 comprises multiple optical fibers 11, multiple bundle materials 12, a water-absorbing tape 13, and an internal sheath 14. Each bundle material 12 bundles multiple optical fibers 11 together. In the example shown in Figure 1, the core 10 contains a total of 12 optical fiber units, each consisting of an optical fiber 11 and a bundle material 12. The water-absorbing tape 13 encloses these optical fiber units. The water-absorbing tape 13 is made of a water-absorbing material and serves to prevent water from entering the core 10. The internal sheath 14 is cylindrical in shape and extends in the longitudinal direction, covering the water-absorbing tape 13. The material of the internal sheath 14 can be a resin such as polyethylene (PE) or polyvinyl chloride (PVC).

[0012] The number of optical fiber units included in the core 10 can be changed as appropriate. In the example in Figure 1, the core 10 has three optical fiber units that make up the inner layer and nine optical fiber units that make up the outer layer. However, the cross-sectional shape of the core 10 does not have to be uniform as in Figure 1, and the optical fiber units do not have to be divided into inner and outer layers. Also, the bundle material 12, water-absorbing tape 13, and internal sheath 14 are optional. In other words, the optical fiber 11 does not have to make up an optical fiber unit. Furthermore, the number of optical fibers 11 arranged in the core 10 is not limited to multiple fibers, and may be just one. The core 10 may consist of only one optical fiber 11.

[0013] The reinforcing member 30 is a cylindrical member that extends in the longitudinal direction and surrounds the core 10 and the regulating member 20. The reinforcing member 30 may be constructed by forming a sheet-like member into a cylindrical shape that surrounds the core 10 and the regulating member 20. As for the material of the reinforcing member 30, for example, metal (iron, stainless steel, copper, copper alloy, etc.) can be used. Alternatively, fiber sheets using glass fibers or aramid fibers, or FRP (Fiber Reinforced Plastics) can be used. It may also be used as a reinforcing member 30. The thickness of the reinforcing member 30 is, for example, about 0.1 to 0.3 mm. By setting the thickness of the reinforcing member 30 within this range, it is possible to prevent damage to the optical fiber of the core 10 due to animal damage, etc., and to facilitate the operation of cutting the reinforcing member 30 with the rip cord 60. Note that the reinforcing member 30 is not required to be placed. Whether or not to place the reinforcing member 30 may be selected depending on, for example, the specifications of the optical fiber cable 1A or the location where it is laid.

[0014] The reinforcing member 30 surrounds the core 10 over the entire circumference and may be overlapped at a part in the circumferential direction. The overlapping part of the reinforcing member 30 is called the overlapping portion 30a. The strength of the overlapping portion 30a is high. Therefore, in the overlapping portion 30a, it is difficult to tear the reinforcing member 30 by the lip cord 60 as compared with other parts of the reinforcing member 30. Also, when the lip cord 60 contacts the edge 31 of the reinforcing member 30, the lip cord 60 may break. Therefore, the overlapping portion 30a and the lip cord 60 are arranged apart from each other in the circumferential direction.

[0015] For example, an adhesive layer may be provided on both surfaces of the reinforcing member 30. In this case, the reinforcing member 30 can be adhesively fixed to the sheath 40 by the adhesive layer, and the ends of the reinforcing member 30 can be adhesively fixed to each other in the overlapping portion 30a. However, the adhesive layer may not be provided on one surface or both surfaces of the reinforcing member 30. Note that the reinforcing member 30 wraps around the core 10 over the entire circumference. For example, the overlapping portion 30a may not be formed, and in a cross-sectional view, the core 10 may be surrounded by the reinforcing member 30 when the edges 31 of the ends of the reinforcing member 30 contact each other. In this case, the edges 31 of the reinforcing member 30 may be adhesively fixed to each other.

[0016] The sheath 40 houses the core 10, the regulating member 20, the lip cord 60, and the reinforcing member 30. The sheath 40 is formed in a tubular shape extending in the longitudinal direction. As the material of the sheath 40, resins such as polyethylene (PE) and polyvinyl chloride (PVC) can be used.

[0017] The tensile strength members 50 are used, for example, in pairs of two, and two pairs of tensile strength members 50 (that is, a total of four) are embedded in the sheath 40 so as to sandwich the core 10 in a cross-sectional view. A group of tensile strength members consisting of a plurality of tensile strength members is also called a tensile strength member group. That is, the optical fiber cable 1A has a pair of tensile strength member groups arranged in the sheath 4 outside the core 10. Each tensile strength member 50 extends in the longitudinal direction so as to be parallel to the core 10. The tensile body 50 has the role of protecting the optical fiber 11 from the tension acting on the optical fiber cable 1A. The material of the tensile body 50 is, for example, a metal wire (such as a steel wire), a tensile fiber (such as an aramid fiber), FRP, etc. The tensile body 50 may be a single wire, or may be a wire formed by bundling a plurality of elementary wires or twisting them together.

[0018] Due to the arrangement of the tensile body 50, a bending directionality occurs in the optical fiber cable 1A. Specifically, the optical fiber cable 1A is likely to bend in a direction perpendicular to the neutral line L (see FIG. 1), and is difficult to bend in a direction parallel to the neutral line L. When four tensile bodies 50 are arranged as shown in FIG. 1, the midpoints of the tensile body groups including two adjacent tensile bodies 50 are defined at two locations. The straight line connecting these two midpoints becomes the neutral line L. The neutral line L may pass through the central axis O. Note that the number and arrangement of the tensile bodies 50 can be changed as appropriate. Although an example in which one set of tensile body groups has two tensile bodies 50 has been described, the number of tensile bodies included in one tensile body group may be one, or may be three or more. The tensile bodies 50 may be arranged so that no bending directionality occurs (that is, so that the neutral line L is not defined). Further, the tensile bodies 50 may be arranged in the core 10 without being embedded in the sheath 40. Alternatively, the optical fiber cable 1A may not include the tensile bodies 50.

[0019] The lip cord 60 is used during the operation of tearing the reinforcing member 30 and the sheath 40 (hereinafter simply referred to as the tearing operation). The lip cord 60 is required to have a mechanical strength (such as tensile strength) sufficient to cut the reinforcing member 30 and the sheath 40. As the lip cord 60, a yarn formed by twisting fibers such as PP (polypropylene) or polyester can be used. While the tensile body 50 has the role of protecting the optical fiber 11 from tension, the lip cord 60 has the role of tearing the sheath 40. Therefore, the materials of the lip cord 60 and the tensile body 50 are different. Specifically, the tensile elastic modulus of the tensile body 50 is larger than that of the lip cord 60. Also, the lip cord 60 is more flexible than the tensile body 50.

[0020] The two rip cords 60 are positioned so as to sandwich the core 10 in a cross-sectional view. This arrangement allows the reinforcing member 30 and the sheath 40 to be separated into two parts when the two rip cords 60 are used to tear them apart. This makes it easier to remove the core 10 from the inside of the sheath 40.

[0021] Furthermore, in the example shown in Figure 1, the two rip cords 60 and the central axis O are aligned in a straight line in a cross-sectional view, and the line connecting the two rip cords 60 is perpendicular to the neutral line L. This prevents the rip cords 60 from hitting the tensile strength body 50 when tearing the sheath 40, making it easier to divide the sheath 40 into semi-cylindrical sections. However, it is still possible to tear the sheath 40 and extract the core 10 even if the two rip cords 60 and the central axis O are not aligned in a straight line. The rip cords 60 and the tensile strength body 50 may be positioned at different locations in the circumferential direction so that the rip cords 60 do not hit the tensile strength body 50 when tearing the sheath 40. Furthermore, the number of ripcords 60 does not have to be two; it may be one or three or more. Even if there is only one ripcord 60, it is still possible to tear open the sheath 40 and extract the core 10.

[0022] The sheath 40 may be provided with a mark to indicate the position of the rip cord 60. The mark may be, for example, a colored portion provided on the outer surface of the sheath 40, or a groove recessed from the outer surface of the sheath 40, or a projection protruding from the outer surface. Alternatively, the worker may determine the position of the rip cord 60 based on the bending direction of the optical fiber cable 1A. In this case, a mark indicating the position of the rip cord 60 is not necessary.

[0023] One method for removing the core 10 from the optical fiber cable 1A is to first partially cut open the sheath 40 and reinforcing member 30 with a tool such as a cutter. Next, insert a tool such as pliers into the cut-open section, grasp the rip cord 60, and pull it out to the outside of the sheath 40. This operation tears the reinforcing member 30 and sheath 40 through the rip cord 60 which extends in the longitudinal direction, allowing the core 10 to be removed. Then, by cutting open the internal sheath 14 etc. of the core 10, the optical fiber 11 can be removed.

[0024] Here, an annular gap is provided outside the core 10 and inside the sheath 40 (in this embodiment, between the reinforcing member 30 and the core 10) for positioning the rip cord 60. If the rip cord 60 moves circumferentially within this gap, it may take time for the worker to find the rip cord 60, potentially reducing work efficiency. Also, if the rip cord 60 moves and approaches the overlapping portion 30a of the reinforcing member 30, it may become impossible to tear the high-strength overlapping portion 30a, or the rip cord 60 may come into contact with the edge 31 and break, leading to further reductions in work efficiency.

[0025] Therefore, in this embodiment, a restricting member 20 is provided to suppress the movement of the rip cord 60 in the circumferential direction. The restricting member 20 may be, for example, a water-absorbing sheet (such as a retaining wrap). In this case, the restricting member 20 can also improve the waterproof performance of the optical fiber cable 1A. The material of the restricting member 20 may be the same as or different from that of the water-absorbing tape 13. Examples of materials for the restricting member 20 include fibrous interpositions, a material of the same material as the reinforcing member 30, adhesive, resin sheet, or nonwoven fabric. If the restricting member 20 is an adhesive, the sheath 40 and the core 10 may be bonded together by the restricting member 20.

[0026] The restricting member 20 is attached longitudinally to the core 10. The restricting member 20 is also in sheet form and is wrapped around the core 10. In cross-sectional view, the restricting member 20 is C-shaped and does not cover the core 10 in a portion of the circumferential direction. In cross-sectional view, if W is the total circumferential length of the restricting member 20 (i.e., the width of the restricting member 20 before it is wrapped around the core 10) and Dc is the outer diameter of the core 10, then W is smaller than the outer circumference dimension of the core 10, πDc. In other words, a region S is provided between the two ends of the restricting member 20 in the circumferential direction. The restricting member 20 has a first portion 21 which is part of the restricting member 20, and a second portion 22 which is part of the restricting member 20 different from the first portion 21. Region S is provided between the first portion 21 and the second portion 22. In this embodiment, the circumferential ends of the restricting member 20 are the first portion 21 and the second portion 22. The rip cord 60 is positioned between the first portion 21 and the second portion 22. In other words, the rip cord 60 is sandwiched between the first portion 21 and the second portion 22. When the rip cord 60 tries to move in the circumferential direction, such movement is suppressed because the rip cord 60 comes into contact with the first portion 21 or the second portion 22.

[0027] When a reinforcing member 30 is provided and its ends overlap at the overlapping portion 30a, the first portion 21 and the second portion 22 are positioned away from the overlapping portion 30a of the reinforcing member 30 in the circumferential direction. That is, in the circumferential direction, the region S and the overlapping portion 30a of the reinforcing member 30 are positioned at different locations from each other. This prevents the edge 31 of the reinforcing member 30 from coming into contact with the rip cord 60, thus preventing the rip cord 60 from being damaged or cut by the edge 31 of the reinforcing member 30. The overlapping portion 30a of the reinforcing member 30 is positioned within a range of ±45° around the central axis O from the neutral line L, and the overlapping portion 30a of the reinforcing member 30 and the region S may be positioned at different locations in the circumferential direction. In this case, it is possible to more reliably prevent the edge 31 of the reinforcing member 30 from coming into contact with the rip cord 60.

[0028] In this embodiment, there is only one region S, but multiple regions S may be provided, taking into consideration the number and arrangement of the rip cords 60. In this case, multiple regions S may be provided using multiple restricting members 20, and the materials of each of the multiple restricting members 20 may be different. Alternatively, the core 10 and the restricting member 20 may be bonded together. In this case, it is possible to prevent the rip cord 60 from getting caught between the core 10 and the restricting member 20.

[0029] The following describes an example of a manufacturing method for optical fiber cable 1A. However, other manufacturing methods may be used.

[0030] First, prepare core 10 (step 1). Next, the sheet that will become the restricting member 20 is attached vertically to the core 10 (second step). More specifically, the restricting member 20 is wrapped around the core 10 from the bottom in the direction of gravity. At this time, the width W of the sheet (the dimension in the direction perpendicular to the longitudinal direction of the core 10) is made shorter than the outer circumference dimension πDc of the core 10. As a result, the upper part of the core 10 in the direction of gravity is not covered by the restricting member 20, and in that part, the first part 21 and the second part 22 of the restricting member 20 face each other.

[0031] Next, two rip cords 60 are attached longitudinally to the core 10 and the regulating member 20. More specifically, one rip cord 60 is placed in the area between the first section 21 and the second section 22. The remaining rip cord 60 is attached longitudinally to the regulating member 20 from below in the direction of gravity. Next, the core 10, the restricting member 20, and the rip cord 60 are wrapped with the reinforcing member 30 (third step). Next, a sheath 40 is formed around the reinforcing member 30, for example, by extrusion molding (fourth step). This yields the optical fiber cable 1A.

[0032] In the manufacturing process of the optical fiber cable 1A, the rip cord 60 positioned above the core 10 in the direction of gravity may attempt to move in the circumferential direction due to the influence of gravity. However, in this embodiment, the movement of the rip cord 60 is suppressed by its contact with the first portion 21 or the second portion 22. Therefore, it is possible to manufacture an optical fiber cable 1A in which the rip cord 60 is positioned in a predetermined location more easily.

[0033] Furthermore, the rip cord 60 positioned below the core 10 in the direction of gravity is located at the very bottom of the gap between the regulating member 20 and the reinforcing member 30. Therefore, with respect to the rip cord 60, movement in the circumferential direction is unlikely to occur even without movement suppression by the regulating member 20, and it can be easily positioned in a predetermined location. The rip cord 60 positioned below the core 10 in the direction of gravity may be positioned in a region S formed between the first part 21 and the second part 22 of the regulating member 20. Alternatively, two regions S may be provided, and both the rip cord 60 positioned above the core 10 in the direction of gravity and the rip cord 60 positioned below it may be positioned between the first part 21 and the second part 22 of the regulating member 20.

[0034] As described above, the optical fiber cable 1A of this embodiment comprises a core 10 having an optical fiber 11, a regulating member 20 attached longitudinally to the core 10 and covering the core 10, a sheath 40 covering the regulating member 20, and a rip cord 60 located between the sheath 40 and the core 10, wherein the rip cord 60 is located between the first part 21 and the second part 22 of the regulating member 20. This configuration makes it possible to suppress the rip cord 60 from moving in the circumferential direction.

[0035] Furthermore, the optical fiber cable 1A further includes a reinforcing member 30 positioned between the restricting member 20 and the sheath 40. This prevents damage to the optical fiber 11 of the core 10 due to animal damage or other factors.

[0036] Furthermore, the optical fiber cable 1A further comprises a tensile strength member 50 disposed within the sheath 40, and in a cross-sectional view, the rip cord 60 and the tensile strength member 50 are positioned at different locations in the circumferential direction. This ensures that the rip cord 60 does not come into contact with the tensile strength member 50 when tearing the sheath 40, making the tearing process easier.

[0037] Furthermore, it is more preferable that the rip cord 60 is located between the first portion 21 and the second portion 22 along the entire length of the optical fiber cable 1A in the longitudinal direction. In this case, the movement of the rip cord 60 can be restricted more reliably. However, if the rip cord 60 is located between the first portion 21 and the second portion 22 in at least one cross-section, the position of the rip cord 60 is constrained at that point, and the effect of restricting movement can be extended along the entire length of the rip cord 60. Therefore, it is not essential that the rip cord 60 is located between the first portion 21 and the second portion 22 along the entire length of the longitudinal direction.

[0038] Furthermore, if the optical fiber cable 1A has multiple rip cords 60, it is sufficient that at least one of the multiple rip cords 60 is located between the first section 21 and the second section 22. For example, in an optical fiber cable 1A having two rip cords 60, one rip cord 60 may be located between the first section 21 and the second section 22, while the other rip cord 60 is not located between the first section 21 and the second section 22, but rather between the regulating member 20 and the reinforcing member 30.

[0039] (Second Embodiment) Next, a second embodiment of the present invention will be described, which has the same basic configuration as the first embodiment. For this reason, the same reference numerals are used for similar components, and their descriptions are omitted; only the differences will be described.

[0040] As shown in Figure 2, the configuration of the first portion 21 and the second portion 22 that sandwich the rip cord 60 in the optical fiber cable 1B of this embodiment differs from that of the first embodiment. In this embodiment, the restricting member 20 covers the entire circumference of the core 10. Furthermore, both ends of the restricting member 20 overlap in the circumferential direction. The total length W of the restricting member 20 in the circumferential direction is greater than the outer circumference dimension πDc of the core 10. The rip cord 60 is sandwiched between the overlapping portions of both ends of the regulating member 20 in the circumferential direction. In other words, in this embodiment, the first portion 21 and the second portion 22, which are both ends of the regulating member 20, are arranged to overlap in the radial direction, and the rip cord 60 is sandwiched radially between the first portion 21 and the second portion 22. A region S is provided between the first portion 21 and the second portion 22, and the rip cord 60 is arranged in region S. As shown in Figure 2, the overlap width D is defined as the circumferential width of the portion where the first part 21 and the second part 22 overlap. The rip cord 60 is positioned within the overlap width D in the circumferential direction. Even with this configuration, the same effects as in the first embodiment can be obtained.

[0041] (Third embodiment) Next, a third embodiment of the present invention will be described, which has the same basic configuration as the first embodiment. For this reason, the same reference numerals are used for similar components, and their descriptions are omitted; only the differences will be described.

[0042] As shown in Figure 3, in the optical fiber cable 1C of this embodiment, the configuration of the first portion 21 and the second portion 22 that sandwich the rip cord 60 differs from that of the first embodiment. In this embodiment, the circumferential total length W of the restricting member 20 is greater than the outer circumference dimension πDc of the core 10, and a folded portion 20a is formed on the restricting member 20. The folded portion 20a is, for example, a portion where one end of the restricting member 20 in the circumferential direction is folded back. The folded portion 20a has a bent portion 20b where the restricting member 20 is bent, and an opening 20c of a region S that accommodates the rip cord 60. Note that the folded portion 20a may also be provided in the middle portion of the restricting member 20 in the circumferential direction. The rip cord 60 is sandwiched between two opposing surfaces of this folded portion 20a. These two opposing surfaces are the surface of the first portion 21 and the surface of the second portion 22, respectively. In this embodiment, the two opposing surfaces of the folded portion 20a are the surface of the first portion 21 facing radially outward, and the surface of the second portion 22, which is located radially outward from the first portion 21, facing radially inward. In other words, the folded portion 20a is composed of a first portion 21 and a second portion 22 that sandwich the rip cord 60. The fact that the first portion 21 and the second portion 22 sandwich the rip cord 60 in the radial direction is common to the second embodiment. Even with this configuration, the same effects as in the first embodiment can be obtained.

[0043] As shown in Figure 3, the overlap width D is defined as the circumferential width of the overlapping portion of the first portion 21 and the second portion 22 (i.e., the width of the folded portion 20a). In this embodiment, the rip cord 60 is positioned in the center of the overlap width D. The rip cord 60 only needs to be positioned within the folded portion 20a in the circumferential direction. For example, the rip cord 60 may be positioned in contact with the bent portion 20b within the region S, or it may be positioned near the opening 20c.

[0044] In a cross-sectional view, the restricting member 20 has an end portion of the restricting member 20 with a folded portion 20a, and an end portion 23 of the restricting member 20 on the opposite side of the said end portion. The end portion 23 does not have a folded portion. The end portion 23 is located radially inward of the folded portion 20a. In the circumferential direction, the edge of the end portion 23 is located at the same position as the opening 20c of the folded portion 20a, but in this example, the edge of the end portion 23 may be located within the overlap width D of the folded portion 20a in the circumferential direction.

[0045] In the optical fiber cables 1A and 1B of the first and second embodiments, when the rip cord 60 moves in the circumferential direction, it is conceivable that the rip cord 60 may get caught between the restricting member 20 and the core 10. In contrast, in this embodiment, even if the rip cord 60 moves and comes out from the folded portion 20a, the possibility of the rip cord 60 getting caught between the restricting member 20 and the core 10 is reduced. Therefore, the worker can find the rip cord 60 more easily. Furthermore, if the core 10 and the restricting member 20 are bonded together, the possibility of the rip cord 60 getting caught between the core 10 and the restricting member 20 can be further suppressed.

[0046] The following describes one example of a manufacturing method for optical fiber cable 1C. However, other manufacturing methods may be used.

[0047] First, prepare a Core 10. Next, a sheet that will become the restricting member 20 is placed vertically on the core 10. For example, the restricting member 20 is wrapped around the core 10 from the bottom in the direction of gravity. In this embodiment, one end of the restricting member 20 is bent in the upper part of the core 10 in the direction of gravity, so that the first part 21 and the second part 22 of the restricting member 20 face each other to form a folded portion 20a. When bending one end of the restricting member 20, the rip cord 60 is positioned inside the folded portion 20a. If two rip cords 60 are provided, one rip cord 60 may be positioned between the first portion 21 and the second portion 22, and the remaining rip cord 60 may be attached vertically to the restricting member 20 from below in the direction of gravity. Subsequently, in the same manner as the manufacturing method of the optical fiber cable 1A in the first embodiment, the optical fiber cable 1C can be obtained by providing the reinforcing member 30 and the sheath 40.

[0048] As described above, the method for manufacturing the optical fiber cable 1C in this embodiment includes a first step of preparing a core 10 having an optical fiber 11, a second step of wrapping a restricting member 20 around the core 10, a third step of covering the core 10 having the restricting member 20 with a reinforcing member 30, and a fourth step of covering the reinforcing member 30 with a sheath 40. In the second step, the restricting member 20 is bent and the rip cord 60 is placed inside the folded portion 20a of the restricting member 20.

[0049] In the manufacturing process of the optical fiber cable 1C, the rip cord 60 is fed into the manufacturing line while being subjected to a predetermined tension. Due to the tension applied to the rip cord 60, the rip cord 60 is fed into the manufacturing line in a stable position, so that the rip cord 60 can be reliably positioned inside the folded portion 20a.

[0050] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described, which has the same basic configuration as the first embodiment. For this reason, the same reference numerals are used for similar components, and their descriptions are omitted; only the differences will be described.

[0051] As shown in Figure 4, the configuration of the first portion 21 and the second portion 22 that sandwich the rip cord 60 in the optical fiber cable 1D of this embodiment differs from that of the first embodiment. In addition, in this embodiment, the restricting member 20 has a first restricting member 201 and a second restricting member 202. The first restricting member 201 and the second restricting member 202 are wound around the core 10, and a folded portion 20a is provided at one end of either the circumferentially adjacent first restricting member 201a or the circumferentially adjacent first restricting member 201a or second restricting member 202a. In this embodiment, folded-over portions 20a are provided at both ends 201a of the first restricting member 201, and the first restricting member 201 and the second restricting member 202 cover the entire circumference of the core 10.

[0052] In a cross-sectional view, the total circumferential length of the first restricting member 201 (i.e., the width of the first restricting member 201 before it is wrapped around the core 10) is denoted as W1, and the total circumferential length of the second restricting member 202 (i.e., the width of the second restricting member 202 before it is wrapped around the core 10) is denoted as W2. W1 is greater than W2, and W1 is greater than half of the outer circumference dimension of the core 10, πDc. Of the first restricting member 201 and the second restricting member 202, the second restricting member 202 is positioned closer to the overlapping portion 30a of the reinforcing member 30.

[0053] Each end 201a of the first restricting member 201 has a folded portion 20a formed in the circumferential direction. Since the folded portions 20a have the same configuration as the folded portions 20a described in the third embodiment, they are given the same reference numerals and their description is omitted. The two folded portions 20a of the first restricting member 201 are designated as the first folded portion 20a1 and the second folded portion 20a2, respectively. In a cross-sectional view, the first folded portion 20a1 and the second folded portion 20a2 are arranged so as to sandwich the core 10 between them.

[0054] As shown in Figure 4, the overlap width D of the first folded portion 20a1 is denoted as D1, and the overlap width D of the second folded portion 20a2 is denoted as D2. D1 and D2 may be the same or they may be different. When the outer diameter of the rip cord 60 is Dr, D1 is greater than or equal to Dr, and D2 is greater than or equal to Dr. In this embodiment, the rip cord 60 is positioned in the region S within the folded portion 20a so as to be in contact with the bent portion 20b. However, the rip cord 60 only needs to be positioned within the folded portion 20a in the circumferential direction.

[0055] As shown in Figure 4, in the circumferential direction, the multiple folded portions 20a and the overlapping portions 30a of the reinforcing member 30 are arranged at different positions from each other. For example, the overlapping portions 30a of the reinforcing member 30 may be arranged such that a straight line connecting the central portion W1m of the circumferential total length W1 of the first restricting member 201 and the central portion W2m of the circumferential total length W2 of the second restricting member 202 intersects with the overlapping portions 30a of the reinforcing member 30. In this case, it is possible to more reliably prevent both rip cords 60 from being damaged or cut by the edge 31 of the reinforcing member 30. In the example shown in Figure 4, the central sections W1m and W2m are located on the neutral line L, but this is not the only example, and the central sections W1m and W2m do not necessarily have to be on the neutral line L.

[0056] In the circumferential direction, the bent portion 20b is positioned between the opening 20c and the overlapping portion 30a of the ends of the reinforcing member 30. This folded portion 20a prevents the rip cord 60 from coming into contact with the edge 31 of the reinforcing member 30, even if the rip cord 60 moves outside the folded portion 20a. This prevents the rip cord 60 from being damaged or cut by the edge 31 of the reinforcing member 30.

[0057] No folded portion 20a is provided at the end 202a of the second restricting member 202. The end 202a is positioned radially inward of the folded portion 20a. The edge of the end 202a is positioned in the circumferential direction at the same position as the opening 20c of the folded portion 20a. However, the edge of the end 202a may be positioned within the overlap width D of the folded portion 20a in the circumferential direction.

[0058] In a cross-sectional view, the overlapping portion 30a of the reinforcing member 30 is positioned within a range of ±45° around the central axis O from the neutral line L, and the overlapping portion 30a of the reinforcing member 30 and the central portion W1m of W1 of the first regulating member 201 may be positioned at a distance of 45° or more around the central axis in the circumferential direction. In this case, it is possible to more reliably prevent the edge 31 of the reinforcing member 30 from coming into contact with the rip cord 60.

[0059] The following describes an example of a method for manufacturing the optical fiber cable 1D. The method for manufacturing the optical fiber cable 1D is basically the same as the method for manufacturing the optical fiber cable 1C in the third embodiment. Therefore, only the differences will be described. However, other manufacturing methods may be used.

[0060] Two sheets, which will become the first restricting member 201 and the second restricting member 202, are placed vertically on the prepared core 10. For example, when viewed from the direction of movement of the core 10 on the manufacturing line, the second restricting member 202 is first placed on the side of the core 10 from the right side, and then the first restricting member 201 is placed on the side of the core 10 from the left side. When placing the first restricting member 201, the ends 201a of the first restricting member 201 are made to overlap both ends 202a of the second restricting member 202. At the point where the first restricting member 201 and the second restricting member 202 overlap, the ends 201a of the first restricting member 201 are bent to form two folded portions 20a.

[0061] When bending the end 201a of the first restricting member 201, the rip cord 60 is positioned inside the folded portion 20a. More specifically, the rip cord 60 is positioned on the outer circumferential surface of the end 201a of the first restricting member 201, and the first restricting member 201 is bent at the location where the rip cord 60 is positioned, bringing the first portion 21 and the second portion 22 into contact with the bent portion 20b while the rip cord 60 is in contact with it. Since the rip cord 60 is subjected to a predetermined tension during the manufacturing line, the folded portion 20a can be formed while pressing the rip cord 60 against the location that will become the bent portion 20b. This makes it possible to suppress variations in the position of the rip cord 60 in the longitudinal direction. Furthermore, the end portion 202a of the second restricting member 202 is positioned radially inward of the first restricting member 201, and the core 10 is covered all around by the restricting member 20. This prevents the first restricting member 201 and the second restricting member 202 from moving within the space between the core 10 and the reinforcing member 30.

[0062] As described above, in the optical fiber cable 1D of this embodiment, the folded portion 20a where the first portion 21 and the second portion 22 face each other has a bent portion 20b in which the regulating member 20 is bent and an opening 20c of the region S in which the rip cord 60 is housed, and in the circumferential direction, the bent portion 20b is positioned between the opening 20c and the overlapping portion 30a of the ends of the reinforcing member 30. The presence of the second restricting member 202 prevents the folded portion 20a from moving to a position where it overlaps with the overlapping portion 30a of the reinforcing member 30 in the circumferential direction. This ensures that the rip cord 60 does not come into contact with the edge 31 of the reinforcing member 30.

[0063] Furthermore, the restricting member 20 comprises a first restricting member 201 and a second restricting member 202, and folded portions 20a are formed at both ends 201a of the first restricting member 201 in the circumferential direction, with the first portion 21 and the second portion 22 facing each other. This improves the ease of removing the core 10 using the rip cords 60 that are each positioned at the folded portion 20a.

[0064] (Modified version of the fourth embodiment) As shown in Figure 5, in the optical fiber cable 1D, which is a modified example of the fourth embodiment, the restricting member 20 does not cover the entire circumference of the core 10. More specifically, it differs from the fourth embodiment in that the end portion 202a of the second restricting member 202 does not overlap with the folded portion 20a of the first restricting member 201. As shown in Figure 5, a gap is provided between the first restricting member 201 and the second restricting member 202. The presence of the second restricting member 202 prevents the folded portion 20a from moving to a position where it overlaps with the overlapping portion 30a of the reinforcing member 30 in the circumferential direction. Furthermore, since there is no overlapping portion between the first restricting member 201 and the second restricting member 202, the outer diameter of the optical fiber cable 1D can be reduced. When manufacturing the optical fiber cable 1D shown in Figure 5, the first restricting member 201 may be placed first on the outer surface of the core 10, compared to the first restricting member 201 and the second restricting member 202.

[0065] (Fifth embodiment) Next, a fifth embodiment of the present invention will be described, which has the same basic configuration as the fourth embodiment. For this reason, the same reference numerals are used for similar components, and their descriptions are omitted; only the differences will be described.

[0066] As shown in Figure 6, the optical fiber cable 1E of this embodiment differs from the fourth embodiment in that the first restricting member 201 and the second restricting member 202 each have one folded portion 20a. The first folded portion 20a1 provided on the first restricting member 201 and the second folded portion 20a2 provided on the second restricting member 202 are arranged in a cross-sectional view so as to sandwich the core 10 between them. On the radially inner side of the first folded portion 20a1 provided on the first restricting member 201, the end portion 202a of the second restricting member 202, on which the second folded portion 20a2 is not formed, is positioned. On the radially inner side of the second folded portion 20a2 provided on the second restricting member 202, the end portion 201a of the first restricting member 201, on which the first folded portion 20a1 is not formed, is positioned. In this embodiment, the first restricting member 201 and the second restricting member 202 cover the entire circumference of the core 10, but a gap may be provided between the first restricting member 201 and the second restricting member 202 in the circumferential direction.

[0067] In a cross-sectional view, the total circumferential length W1 of the first restricting member 201 and the total circumferential length W2 of the second restricting member 202 may be equal or different. For example, the overlapping portion 30a of the reinforcing member 30 may be positioned such that a straight line connecting the central portion W1m of the total circumferential length W1 of the first restricting member 201 and the central portion W2m of the total circumferential length W2 of the second restricting member 202 intersects with the overlapping portion 30a of the reinforcing member 30.

[0068] In the first folded portion 20a1, a bent portion 20b is positioned between the opening 20c and the overlapping portion 30a of the ends of the reinforcing member 30 in the circumferential direction. The formation of this first folded portion 20a1 prevents, for example, the rip cord 60 from coming into contact with the edge 31 of the reinforcing member 30 even if it moves outside the first folded portion 20a1. In the second folded portion 20a2, even if the rip cord 60 moves and exits the second folded portion 20a2, the presence of the first regulating member 201 prevents the rip cord 60 from getting caught between the regulating member 20 and the core 10. Therefore, the worker can more easily find the rip cord 60. Furthermore, even when the rip cord 60 moves and exits the second folded portion 20a2, the length between the second folded portion 20a2 and the overlapping portion 30a may be arranged so that the length between the second folded portion 20a2 and the overlapping portion 30a is longer than the length between the first folded portion 20a1 and the overlapping portion 30a, so that the edge 31 of the reinforcing member 30 and the rip cord 60 are less likely to come into contact.

[0069] The method for manufacturing the optical fiber cable 1E differs from the method for manufacturing the optical fiber cable 1D described in the fourth embodiment in that two restricting members 201 and 202 are placed on the side surface of the core 10 so that the ends of the restricting member 20 on which the folded portion 20a is formed are radially outward, and one end 201a of the first restricting member 201 and one end 202a of the second restricting member 202, which are positioned radially outward, are bent, but the basic method is the same. The method for manufacturing the optical fiber cable 1E can also obtain the same effects as the method for manufacturing the optical fiber cable 1D described in the fourth embodiment. However, other manufacturing methods may be used.

[0070] As described above, in the optical fiber cable 1E of this embodiment, the restricting member 20 comprises a first restricting member 201 and a second restricting member 202. A folded portion 20a is formed at one end 201a of the first restricting member 201 and one end 202a of the second restricting member 202, where the first portion 21 and the second portion 22 face each other. The folded portion 20a is provided at either the end 201a of the first restricting member 201 or the end 202a of the second restricting member 202 that are adjacent in the circumferential direction. This improves the ease of removing the core 10 using the rip cords 60 that are each positioned at the folded portion 20a.

[0071] Next, the above embodiments will be described using examples. However, the present invention is not limited to the following examples.

[0072] (Example 1) In accordance with the first embodiment, an optical fiber cable 1A having 144 intermittently fixed tape cores was fabricated. Each intermittently fixed tape core has 12 optical fibers 11 and a connecting portion that intermittently connects these optical fibers 11. In other words, the optical fiber cable 1A in Embodiment 1 has a total of 1728 optical fibers 11. A water-absorbing tape with a width of 60 mm (i.e., a circumference of 60 mm in cross-sectional view) was used as the regulating member 20. The diameter of the rip cord 60 was 1.0 mm.

[0073] Here, the percentage of the outer surface of the core 10 (in the example in Figure 1, the outer surface of the internal sheath 14) that is not covered by the restricting member 20 is expressed as the aperture ratio R1 (%). Specifically, the aperture ratio R1 can be calculated using the following formula (1). R1 = θ ÷ 360° × 100 …(1) In equation (1), θ is the angle formed by the line connecting the central axis O and the first part 21, and the line connecting the central axis O and the second part 22, as shown in Figure 1.

[0074] In this example, as shown in Table 1, several samples were prepared with different opening ratios R1 ranging from 5% to 50%. In Table 1, "opening width" refers to the length in the circumferential direction of the area of ​​the outer surface of the core 10 that is not covered by the restricting member 20. Also, "opening width / rip cord diameter" is the value obtained by dividing the opening width by the diameter of the rip cord 60.

[0075] [Table 1]

[0076] Table 1's "Core Removal Ease of Use" indicates that for each sample created, if the rip cord 60 broke when tearing the reinforcing member 30 and sheath 40 using the rip cord 60, the "Core Removal Ease of Use" was considered NG. Table 1's "Waterproofing Characteristics" shows the results of waterproofing tests conducted on each sample. Specifically, for each 3m long sample, a test was conducted according to the "water penetration" conditions (tap water, sample length 3m, water head length 1m, with orifice, no pre-soaking) described in section 6.6.7 of Telcordia GR-20 issue 4, July, 2013, and if water was seeped through the entire length of the sample, it was considered NG.

[0077] As shown in Table 1, when the opening ratio R1 was 35% or less, the core removal workability was improved. Furthermore, when the opening ratio R1 was 30% or less, the waterproofing properties were also improved. Based on the above, the aperture ratio R1 is preferably 35% or less, and more preferably 30% or less.

[0078] The lower limit of the opening ratio R1 is not particularly limited, as long as the rip cord 60 can be positioned between the first section 21 and the second section 22. The opening width is preferably larger than the rip cord diameter.

[0079] (Example 2) In accordance with the third embodiment, an optical fiber cable 1C having 144 intermittently fixed tape cores was fabricated. Each intermittently fixed tape core has 12 optical fibers 11 and a connecting portion that intermittently connects these optical fibers 11. That is, the optical fiber cable 1C in Embodiment 2 has a total of 1728 optical fibers 11. A water-absorbing tape with a width of 60 mm (i.e., a circumference of 60 mm in cross-sectional view) was used as the regulating member 20. The diameter of the rip cord 60 was 1.0 mm.

[0080] In this example, as shown in Table 2, multiple samples were prepared with overlap widths D varying in the range of 1.0 to 10.0 mm. The "overlap width D / rip cord diameter" is the value obtained by dividing the overlap width D by the diameter of the rip cord 60. The "core removal workability" and "waterproofing characteristics" in Table 2 are the same as in Table 1.

[0081] [Table 2]

[0082] As shown in Table 2, when the overlap width D / rip cord diameter was 5.0 or greater, the core removal workability was improved. Therefore, it is preferable that the overlap width D / rip cord diameter be 5.0 or greater. In this embodiment, the case where the first portion 21 and the second portion 22 are folded portions 20a was examined, as shown in Figure 3. However, it is believed that the effect of setting the overlap width D / lip cord diameter to 5.0 or more can be obtained similarly even when the first portion 21 and the second portion 22 are both ends of the restricting member 20, as shown in Figure 2. The overlap width D in Figure 2 can be defined in the same way as the overlap width D in Figure 3.

[0083] (Example 3) A fiber optic cable 1D having 24 intermittently fixed tape cores corresponding to the fiber optic cable 1D shown in Figure 4 of the fourth embodiment was created. Each intermittently fixed tape core has 12 optical fibers 11 and a connecting portion that intermittently connects these optical fibers 11. That is, the fiber optic cable 1D in Embodiment 3 has a total of 288 optical fibers 11. Here, the outer diameter Dc of the core 10, the total circumferential length W1 of the first restricting member 201, the total circumferential length W2 of the second restricting member 202, and the outer diameter Dr of the rip cord 60 satisfy the following equations (2) to (4). πDc / 2<W1 …(2) W1> W2 …(3) Dr ≤ D1 and Dr ≤ D2 …(4)

[0084] Furthermore, in order to improve the ease of core removal, it is desirable to satisfy the following equation (5). 0.6 × πDc / 2 <W1-(D1+D2)<1.3×πDc / 2 …(5) From equation (5), by comparing the sizes of W1-(D1+D2) and πDc, it is possible to determine how much of the entire circumference of the core 10 is covered by the first restricting member 201. By keeping the proportion of the core 10 covered by the first restricting member 201 within an appropriate range, it is possible to reliably prevent the rip cord 60 from coming into contact with the edge 31 of the reinforcing member 30, and to improve the ease of removing the core 10. Furthermore, it is believed that the optical fiber cable 1D (see Figure 5), which is a modified example of the fourth embodiment, can also be made easier to remove the core 10 by satisfying the above formula (5).

[0085] The technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0086] For example, optical fiber cables 1A to 1E do not need to have the reinforcing member 30. Even without the reinforcing member 30, a problem may arise where the worker cannot find the rip cord 60 when it moves in the circumferential direction, resulting in reduced work efficiency. In other words, the configuration of this disclosure is effective even in optical fiber cables without the reinforcing member 30.

[0087] Furthermore, in the first embodiment, the thickness of both ends of the regulating member 20 in the circumferential direction (i.e., the thickness of the first portion 21 and the second portion 22) may be greater than the thickness of other parts of the regulating member 20. In this case, the rip cord 60 is prevented from crossing over the first portion 21 and the second portion 22 in the circumferential direction, and the movement of the rip cord 60 can be restricted more reliably.

[0088] Furthermore, in the third embodiment, in the example shown in Figure 3, the bent portion 20b, the opening 20c, and the overlapping portion 30a are arranged in this order in the circumferential direction, but the opening 20c, the bent portion 20b, and the overlapping portion 30a may be arranged in this order in the circumferential direction. In this case, even if the rip cord 60 placed inside the folded portion 20a moves out of the opening 20c, it is possible to prevent the rip cord 60 from coming into contact with the edge 31 of the reinforcing member 30.

[0089] Furthermore, the first portion 21 and the second portion 22 of the regulating member 20 may be in partial direct contact in region S. For example, in a cross-sectional view, the size of the opening in region S in the example shown in Figure 2, and the size of the opening 20c in the examples shown in Figures 3 to 6, are equivalent to the outer diameter Dr of the rip cord 60, but the first portion 21 and the second portion 22 of the regulating member 20 may be in partial contact in these openings. Alternatively, the size of these openings may be smaller than the outer diameter Dr of the rip cord 60. Even in these cases, when removing the core 10 from the optical fiber cable, it is possible to insert a tool such as pliers through a partially cut-open section of the sheath 40 and reinforcing member 30, widen the folded portion 20a, and remove the rip cord 60.

[0090] Furthermore, the restricting member 20 does not have to cover the entire circumference of the core 10. For example, if multiple restricting members 20 are arranged in optical fiber cables 1A to 1E, a gap may be provided between two adjacent restricting members 20 in the circumferential direction.

[0091] Furthermore, without departing from the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments and modifications may be combined as appropriate. [Explanation of Symbols]

[0092] 1A~1E…Optical fiber cable 10…Core 11…Optical fiber 20…Regulating member 20a…Folded section 20b…Bend section 20c…Opening 21…First section 22…Second section 201…First restricting member 202…Second restricting member 30…Reinforcement member 30a…Overlap 40…Sheath 50…Tensile member 60…Rip cord L…Neutral line R1…Opening ratio S…Region W1m…Center of the total length in the circumferential direction of the first restricting member W2m…Center of the total length in the circumferential direction of the second restricting member

Claims

1. A core containing optical fibers, A restricting member that is attached vertically to the core and covers the core, A sheath covering the aforementioned regulating member, A rip cord located between the sheath and the core, The rip cord is located between the first and second parts of the restricting member. The first and second portions are arranged radially to sandwich the rip cord, The regulating member is provided with a folded portion having two opposing surfaces, An optical fiber cable in which the two surfaces are the surface of the first portion and the surface of the second portion, respectively.

2. A core having an optical fiber, A restricting member that is attached vertically to the core and covers the core, A sheath covering the aforementioned regulating member, A rip cord located between the sheath and the core, The rip cord is located between the first and second parts of the restricting member. An optical fiber cable in which the regulating member does not cover the entire circumference of the core.

3. The optical fiber cable according to claim 2, wherein the first and second portions are both ends of the regulating member in the circumferential direction and are arranged to sandwich the rip cord in the circumferential direction.

4. The optical fiber cable according to claim 3, wherein, in a cross-sectional view, the aperture ratio R1, which is the ratio of the outer surface of the core that is not covered by the restricting member, is 35% or less.

5. The optical fiber cable according to claim 1, wherein the folded portion is formed at the end of the restricting member in the circumferential direction.

6. The optical fiber cable according to claim 1 or 5, wherein, in a cross-sectional view, the value obtained by dividing the circumferential dimension of the overlapping portion of the first portion and the second portion by the diameter of the rip cord is 5.0 or greater.

7. The optical fiber cable according to any one of claims 1 to 5, wherein the rip cord is located between the first portion and the second portion along the entire length of the core in the longitudinal direction.

8. The optical fiber cable according to any one of claims 1 to 5, further comprising a reinforcing member disposed between the regulating member and the sheath.

9. The sheath further comprises a tensile strength member disposed within the sheath, The optical fiber cable according to any one of claims 1 to 5, wherein, in a cross-sectional view, the rip cord and the tensile strength member are arranged at different positions in the circumferential direction.

10. The system further comprises a reinforcing member disposed between the regulating member and the sheath, The folded portion where the first portion and the second portion face each other has a bent portion in which the regulating member is bent and an opening in the area in which the rip cord is housed. The optical fiber cable according to claim 1 or 5, wherein the bent portion is positioned in the circumferential direction between the opening and the overlapping portion of the ends of the reinforcing member.

11. The regulating member comprises a first regulating member and a second regulating member, The optical fiber cable according to claim 1 or 5, wherein the folded portions are formed at both ends of the first regulating member in the circumferential direction, with the first portion and the second portion facing each other.

12. The system further comprises a reinforcing member disposed between the regulating member and the sheath, The optical fiber cable according to claim 11, wherein, in a cross-sectional view, a straight line connecting the central part of the circumferential total length of the first restricting member and the central part of the circumferential total length of the second restricting member intersects with the overlapping portion of the ends of the reinforcing members.

13. A reinforcing member is disposed between the regulating member and the sheath, The system further comprises a pair of tensile strength members arranged within the sheath, flanking the core, In a cross-sectional view, overlapping portions where the ends of the reinforcing members overlap are arranged within a range of ±45° around the central axis, from the neutral line connecting the central axis of the optical fiber cable and the midpoint in the circumferential direction of each tensile strength member group. The optical fiber cable according to claim 11, wherein the overlapping portion and the central portion of the circumferential total length of the first regulating member are arranged at a distance of 45° or more around the central axis.

14. When the outer diameter of the core is Dc, the total length in the circumferential direction of the first restricting member is W1, the total length in the circumferential direction of the second restricting member is W2, and the outer diameter of the rip cord is Dr, πDc / 2 < W1, W1 > W2, and Dr ≤ D1 and Dr ≤ D2, An optical fiber cable according to claim 11, satisfying the requirements.

15. The optical fiber cable according to claim 14, satisfying 0.6 × πDc / 2 < W1 - (D1 + D2) < 1.3 × πDc / 2.

16. The regulating member comprises a first regulating member and a second regulating member, At one end of the first restricting member and at one end of the second restricting member, the folded portion is formed such that the first portion and the second portion face each other. The optical fiber cable according to claim 1 or 5, wherein the folded portion is provided at either the end of the first restricting member or the end of the second restricting member that are adjacent in the circumferential direction.

17. The first step is to prepare a core containing optical fibers, A second step involves wrapping a regulating member around the core, A third step involves covering the core having the regulating member with a reinforcing member, The fourth step involves covering the reinforcing member with a sheath, A method for manufacturing an optical fiber cable, wherein the second step involves bending the restricting member and arranging a rip cord inside the folded portion of the restricting member.

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