阅读说明：本技术 光纤保护单元以及光纤保护方法 (Optical fiber protection unit and optical fiber protection method ) 是由 武田力丸 百津仁博 于 2019-09-18 设计创作，主要内容包括：本发明提供一种光纤保护单元以及光纤保护方法。在铺设光纤时容易进行光纤的保护作业。本发明的光纤保护单元具备：以网眼状形成的开口部,在内部插通多根光纤的网眼状管；插通于上述网眼状管,在内部插通多根光纤的管状部件；以及安装于上述网眼状管的端部的筒状部件。网眼状管由于长度方向的伸缩量大,所以在铺设光纤时光纤的保护作业变得容易。另外,在网眼状管的内侧配置管状部件,由此容易使光纤插通于网眼状管。此外,在网眼状管的端部安装筒状部件,由此容易从管状部件的端部抽出网眼状管的端部。(The invention provides an optical fiber protection unit and an optical fiber protection method. The optical fiber is easily protected when the optical fiber is laid. The optical fiber protection unit of the present invention includes: a mesh tube having an opening formed in a mesh shape and through which a plurality of optical fibers are inserted; a tubular member inserted through the mesh tube and having a plurality of optical fibers inserted therein; and a cylindrical member attached to an end of the mesh tube. Since the mesh-like tube has a large amount of expansion and contraction in the longitudinal direction, the optical fiber can be easily protected when the optical fiber is laid. Further, the tubular member is disposed inside the mesh tube, so that the optical fiber can be easily inserted into the mesh tube. Further, the tubular member is attached to the end portion of the mesh-like tube, so that the end portion of the mesh-like tube can be easily pulled out from the end portion of the tubular member.)

1. An optical fiber protection unit, comprising:

a mesh tube having an opening formed in a mesh shape and through which a plurality of optical fibers are inserted;

a tubular member inserted through the mesh tube and having a plurality of optical fibers inserted therein; and

and a cylindrical member attached to an end of the mesh tube.

2. The optical fiber protection unit according to claim 1,

the mesh tube is folded in the longitudinal direction by bending the peripheral edge of the opening.

3. The optical fiber protection unit according to claim 2,

the tubular member is pulled out from the tubular member, and the mesh tube in the folded state can be elongated in the longitudinal direction.

4. The optical fiber protection unit according to any one of claims 1 to 3,

the mesh tube includes:

a plurality of first wires arranged in a spiral shape in a predetermined direction; and

a plurality of second wires arranged in a direction different from the first wires,

and joining the intersections of the first wires and the second wires.

5. The optical fiber protection unit according to claim 4,

and fusion-bonding the intersections of the first wire and the second wire.

6. The optical fiber protection unit according to claim 5,

the cylindrical member is fused and joined to an end of the mesh tube.

7. The optical fiber protection unit according to any one of claims 1 to 6,

the tubular member has a hollow tubular portion and a projecting portion projecting outward from the outer periphery of the tubular portion.

8. The optical fiber protection unit according to claim 7,

the end of the mesh tube is hooked on the protrusion.

9. The optical fiber protection unit according to claim 8,

the edge of the protruding portion is formed with a concave-convex portion.

10. The optical fiber protection unit according to any one of claims 7 to 9,

the protrusion can be inserted into a groove of another component,

the end of the mesh-like tube is fixed to the other member by inserting the protrusion into the groove.

11. An optical fiber protection method is characterized by comprising the following steps:

preparing a protection unit including a mesh tube folded in a longitudinal direction, a tubular member inserted through the mesh tube, and a cylindrical member attached to an end of the mesh tube;

inserting optical fibers into the tubular member, thereby inserting a plurality of optical fibers into the inside of the mesh-like tube in a folded state, an

The tubular member is pulled out from the tubular member, the mesh tube in a folded state is elongated in the longitudinal direction, and the plurality of optical fibers are inserted into the elongated mesh tube.

Technical Field

The present invention relates to an optical fiber protection unit and an optical fiber protection method.

Background

Patent documents 1 to 4 describe optical fiber units in which a binding material is wound around a plurality of optical fiber bundles. Patent documents 3 and 4 describe a method of manufacturing an optical fiber unit by winding a binding material around a plurality of optical fiber bundles.

Further, patent documents 5 to 7 disclose various pipes. Patent document 5 describes a protective tube for protecting an outer periphery of an optical fiber. Patent document 6 describes that a stretchable tubular net is formed by weaving plastic wires or metal wires to protect the wiring. Patent document 7 describes that the electric wire is protected by a mesh tube whose diameter is increased when the electric wire is contracted.

Patent document 1: international publication WO2015/053146

Patent document 2: japanese patent laid-open publication No. 2011-1699939

Patent document 3: japanese patent laid-open publication No. 2013-97320

Patent document 4: japanese patent laid-open publication No. 2018-049081

Patent document 5: japanese laid-open patent publication No. 2017-215438

Patent document 6: japanese Kokai publication Sho 63-49356

Patent document 7: japanese laid-open patent publication No. 2002-10441

The binding material described in patent documents 1 to 4 is wound around the outer periphery of an optical fiber bundle in a manufacturing plant in order to bind a plurality of optical fibers. Therefore, the binding members described in patent documents 1 to 4 neither protect the optical fiber nor insert the optical fiber therethrough. Further, it is not assumed that the binding members described in patent documents 1 to 4 are attached to the outer periphery of the optical fiber bundle at the laying site when the optical fiber is laid (it is difficult to attach the binding members described in patent documents 1 to 4 to the outer periphery of the optical fiber bundle at the laying site when the optical fiber is laid).

In the case of the protection tube described in patent document 5 and the spiral tube described in the prior art of patent document 6, the work of inserting the optical fiber is troublesome. In the case of the braided tube (tube formed by braiding wire rods) described in patent document 6 and patent document, the amount of expansion and contraction in the longitudinal direction is small, and therefore, in this case, too, there is a problem that the work of inserting the optical fiber is troublesome. Further, when inserting an optical fiber into a braided tube whose diameter changes during expansion and contraction, the diameter becomes smaller when the braided tube is elongated in the longitudinal direction, and therefore the optical fiber inserted into the braided tube is pressed, which also causes a problem of increasing the transmission loss of the optical fiber.

Disclosure of Invention

The invention aims to provide an optical fiber protection unit which is provided with a mesh-shaped pipe capable of facilitating protection operation of an optical fiber when the optical fiber is laid and facilitates operation of the mesh-shaped pipe.

In order to achieve the above object, the present invention is a fiber optic connector comprising a mesh tube having an opening formed in a mesh shape and a plurality of optical fibers inserted therein; a tubular member inserted through the mesh tube and having a plurality of optical fibers inserted therein; and a cylindrical member attached to the optical fiber unit at the end of the mesh tube.

Other features of the present invention will be apparent from the description of the specification and the drawings.

According to the present invention, since the optical fiber is protected by the mesh-like tube having a large amount of expansion and contraction in the longitudinal direction, the optical fiber can be easily protected when the optical fiber is laid. Further, since the tubular member is inserted into the mesh tube and the tubular member, the operation of inserting the optical fiber into the mesh tube is facilitated.

Drawings

Fig. 1A is an explanatory diagram of the protection unit 20 of the present embodiment. Fig. 1B is an exploded explanatory view of the protection unit 20 of the present embodiment. Fig. 1C is an explanatory diagram of a state in which the tubular member 24 is removed from the tubular member 22 and the mesh tube 10 is extended.

Fig. 2A and 2B are explanatory views of the mesh tube 10.

Fig. 3A is a developed view for explaining the shape of the mesh tube 10. Fig. 3B is an enlarged perspective view of the mesh tube 10 shown in fig. 3A.

Fig. 4A is a cross-sectional view of the wire rod of the present embodiment. Fig. 4B and 4C are cross-sectional views of other wire members.

Fig. 5A is a development view for explaining another shape of the mesh tube 10. Fig. 5B is an enlarged perspective view of the mesh tube 10 shown in fig. 5A.

Fig. 6A and 6B are developed views for explaining still another shape of the mesh tube 10.

Fig. 7A is an explanatory view of the shape of a braided tube as a comparative example. Fig. 7B is an enlarged explanatory view of the vicinity of the mesh of the braided tube as a comparative example.

Fig. 8A and 8B are explanatory views of the state before and after expansion and contraction in the vicinity of the opening 10A (mesh) of the mesh tube 10 according to the present embodiment.

Fig. 9 is a perspective view of the tubular member 24.

Fig. 10A to 10D are explanatory views of a method for manufacturing the protection unit 20.

Fig. 11A to 11E are explanatory diagrams of a method of protecting the optical fiber 5 using the protection unit 20.

Fig. 12 is an explanatory view of the state inside the holder 40.

Fig. 13 is a perspective view of the storage rack 41 and the branching unit 50.

Fig. 14 is a perspective view of the storage tray 42.

Fig. 15A is an enlarged perspective view of the holding portion 47. Fig. 15B is a diagram showing a state in which the cylindrical member 24 is held by the holding portion 47.

Fig. 16 is an exploded view of the branching unit 50 of the present embodiment.

Fig. 17 is an exploded view of the branching unit 50 of the reference example.

Fig. 18A to 18C are explanatory views of a method of laying optical fibers 5 using the storage tray 42 according to the present embodiment.

Fig. 19A is an explanatory view of a method of measuring flexural rigidity. FIG. 19B is an illustration of a load-deflection line diagram.

Fig. 20 is an explanatory diagram of the pitch P and the inner diameter D.

Detailed Description

At least the following matters will become apparent from the description of the specification and the drawings described later.

A device is provided with: a mesh tube having an opening formed in a mesh shape and through which a plurality of optical fibers are inserted; a tubular member inserted through the mesh tube and having a plurality of optical fibers inserted therein; and a cylindrical member for clarifying the optical fiber unit attached to the end of the mesh tube. According to such an optical fiber protection unit, since the optical fiber is protected by the mesh-like tube having a large amount of expansion and contraction in the longitudinal direction, the optical fiber can be easily protected when the optical fiber is laid. Further, since the tubular member is inserted into the mesh tube, the operation of inserting the optical fiber into the mesh tube is facilitated. Further, since the tubular member is attached to the end portion of the mesh-like tube, the mesh-like tube can be easily pulled out from the tubular member.

Preferably, the mesh-like tube is folded in the longitudinal direction by bending the peripheral edge of the opening. This increases the amount of expansion and contraction in the longitudinal direction of the mesh tube.

Preferably, the tubular member is pulled out from the tubular member, and the mesh tube in the folded state is allowed to extend in the longitudinal direction. This facilitates the optical fiber protection work when laying the optical fiber.

The mesh tube preferably includes: a plurality of first wires arranged in a spiral shape in a predetermined direction; and a plurality of second wires arranged in a direction different from the direction of the first wires, and joining intersections of the first wires and the second wires. This enables the mesh-like tube to be easily manufactured.

Preferably, the first wire and the second wire are melt-bonded at an intersection. This enables the mesh-like tube to be easily manufactured.

Preferably, the cylindrical member is fusion-bonded to an end of the mesh tube. This allows the end of the mesh-like tube to be easily attached to the cylindrical member.

Preferably, the tubular member has a hollow tubular portion and a protruding portion protruding outward from an outer periphery of the tubular portion. This facilitates the optical fiber protection work when laying the optical fiber.

Preferably, an end of the mesh-like tube is hooked on the projection. This makes it easy to attach the end of the mesh tube to the cylindrical member.

Preferably, the projection has a concave-convex portion formed at an edge thereof. This makes it easy for the end of the mesh-like tube to be hooked on the projection.

Preferably, the end of the mesh-like tube is fixed to the other member by inserting the projection into a groove of the other member and inserting the projection into the groove. This makes it easy to fix the end of the mesh tube to another member.

A method comprising the steps of: preparing a protection unit including a mesh tube folded in a longitudinal direction, a tubular member inserted through the mesh tube, and a cylindrical member attached to an end of the mesh tube; an optical fiber protection method is disclosed in which a plurality of optical fibers are inserted into the mesh tube in a folded state by inserting the optical fibers into the tubular member, and the cylindrical member is pulled out from the tubular member, and the mesh tube in the folded state is elongated in the longitudinal direction, so that the plurality of optical fibers are inserted into the elongated mesh tube. According to such an optical fiber protection method, since the optical fiber is protected by the mesh-like tube having a large amount of expansion and contraction in the longitudinal direction, the optical fiber protection work is facilitated when the optical fiber is laid. Further, since the tubular member is inserted into the mesh-like tube and the cylindrical member, the operation of inserting the optical fiber into the mesh-like tube is facilitated.

The embodiment of the protection unit 20 is also referred to as

< basic configuration of protection unit 20 >

Fig. 1A is an explanatory diagram of the protection unit 20 of the present embodiment. Fig. 1B is an exploded explanatory view of the protection unit 20 of the present embodiment. Fig. 1C is an explanatory diagram of a state in which the tubular member 24 (second tubular member 24B) is removed from the tubular member 22 and the mesh tube 10 is extended.

The protection unit 20 is a member for inserting the optical fiber 5 through the mesh tube 10 to protect the optical fiber 5. The protection unit 20 includes a mesh tube 10, a tubular member 22 (tube member), and a cylindrical member 24 (ring member).

Mesh-like tube 10

Fig. 2A and 2B are explanatory views of the mesh tube 10. Fig. 2A shows the mesh tube 10 in an extended state. In addition, fig. 1A also shows an enlarged cross-sectional view of the section a-a. Fig. 2B shows the mesh tube 10 in a folded state. Fig. 2A and 2B show a state in which the optical fiber 5 is inserted into the mesh tube 10.

The mesh tube 10 is a tubular member having a plurality of openings 10A (meshes) formed in a mesh shape. A plurality of openings 10A are formed, and thus a mesh is formed in the mesh tube 10. The mesh-like tube 10 is configured to be foldable in the longitudinal direction by bending a peripheral edge portion 10B around the opening 10A (the peripheral edge portion 10B surrounding the opening 10A). In the present embodiment, the length of the mesh tube 10 after contraction in the longitudinal direction can be 10% or less of the length of the mesh tube 10 in the initial state (extended state) before contraction.

The optical fibers 5 are protected by inserting the plurality of optical fibers 5 into the mesh tube 10. Therefore, the mesh-like tube 10 serves as a protection tube for protecting the optical fiber 5. In the following description, the mesh tube 10 through which the plurality of optical fibers 5 are inserted may be referred to as an "optical fiber unit 3".

Fig. 3A is a developed view for explaining the shape of the mesh tube 10. Fig. 3A shows the mesh-like tube 10 on a cylindrical coordinate system as a case where the mesh-like tube 10 is virtually arranged on a cylindrical surface without bending. The horizontal axis in the figure shows the position in the longitudinal direction. The vertical axis shows an angle from the reference position (0 degrees), and shows a circumferential position on the cylindrical surface. Fig. 3B is an enlarged perspective view of the mesh tube 10 shown in fig. 3A.

The opening 10A (mesh) is surrounded by at least two peripheral edges 10B, and forms a hole penetrating in the radial direction of the mesh tube 10. The peripheral edge portion 10B is a linear (including a band-like or string-like) portion surrounding the opening portion 10A. A peripheral edge portion 10B is present between the opening 10A and the opening 10A. The peripheral edge portion 10B may be referred to as "twisted yarn". The branch portion 10C is formed at the boundary of three or more openings 10A. Three or more peripheral edge portions 10B extend from the branch portion 10C. In the case of the mesh-like tube 10 shown in fig. 3A, a branch portion 10C is formed at the boundary of the four opening portions 10A, and four peripheral edge portions 10B extend from the branch portion 10C. Branch portion 10C may be referred to as a "bridge".

In the present embodiment, the mesh tube 10 is formed of a plurality of first wires 11 formed in a spiral shape in a predetermined direction (S direction) and a plurality of second wires 12 formed in a spiral shape in a direction (Z direction) opposite to the first wires 11. In the present embodiment, the mesh-like tube 10 is formed by the four first wires 11 and the four second wires 12, but the number of wires is not limited to this. The peripheral edge portion 10B of the present embodiment is made of a wire material. The branch portion 10C is formed by the intersection of the two wires. In the present embodiment, the intersection of the two wires is joined (that is, the branch portion 10C of the present embodiment is a joint portion of the two wires). In the present embodiment, the intersection of the two wires is fusion-bonded.

In the present embodiment, as shown in fig. 3B, in the branch portion 10C, two wires are overlapped in a joined state. That is, in the present embodiment, the branch portion 10C has a two-layer structure of two wires after joining, and has a higher strength than a case where the peripheral portion 10B (wire) excluding the branch portion 10C has a one-layer structure. Therefore, in the present embodiment, the peripheral edge portion 10B excluding the branch portion 10C is more easily bent than the branch portion 10C.

In the present embodiment, as shown in fig. 3B, in the branch portion 10C, the two wires are crossed so that the S-direction wire (the first wire 11) is arranged on the Z-direction wire (the second wire 12). That is, in the present embodiment, the S-direction wires (first wires 11) and the Z-direction wires (second wires 12) are not woven. This allows the mesh-like tube 10 to be manufactured more easily than when the wires in two directions are woven (when the first wire 11 in the S direction and the second wire in the Z direction intersect with each other differently).

Fig. 4A is a cross-sectional view of the wire rod of the present embodiment. The wire has a plurality of core portions 13, and a covering portion 14. The core 13 is a fibrous member (core material) extending in the longitudinal direction (longitudinal direction of the wire rod). The covering portion 14 is a covering member that covers the outer periphery of the plurality of core portions 13. The melting point of the covering portion 14 is lower than that of the core portion 13. In the production of the wire rod of the present embodiment, a plurality of fibers covering the core material (core portion 13) with the covering portion 14 are bundled, and the plurality of fibers are fused and integrated at a temperature equal to or higher than the melting point of the covering portion 14 and lower than the melting point of the core portion 13 to form the wire rod. In addition, when the mesh-like tube 10 is manufactured, the covering portion 14 is heated at a temperature equal to or higher than the melting point of the core portion 13 and lower than the melting point of the core portion, and thereby both are thermally fused at the intersection of the S-direction wire (first wire 11) and the Z-direction wire (second wire 12). Since the melting point of the core portion 13 is higher than that of the covering portion 14, the core portion 13 can be in a state of being difficult to melt even when the covering portion 14 is heated to the melting point or more, and the strength of the wire material (the peripheral portion 10B) after welding can be maintained.

The wire rod may be made of a single material instead of the composite material as shown in fig. 4A. The wire shown in fig. 4B is formed by fusing and integrating fibers formed of a core material not covered. The wire shown in fig. 4C is configured in a sheet shape without fusing fibrous members. The wire (the peripheral portion 10B) may be made of a single material as shown in fig. 4B and 4C. In the following description, the structure shown in fig. 4A is sometimes referred to as a "double-layer monofilament", the structure shown in fig. 4B is sometimes referred to as a "single-layer monofilament", and the structure shown in fig. 4C is sometimes referred to as a "film".

As described later, the wire preferably has plasticity. Thus, the mesh-like tube 10 can be configured such that the peripheral edge portion 10B has shape retention in a bent state. For example, if the wire is formed of a double-layer monofilament in which the core portion 13 is made of polyester and the covering portion 14 is made of polypropylene, the mesh-like tube 10 can be formed so that the peripheral edge portion 10B has shape retention in a bent state. However, the material of the wire is not limited to this as long as the mesh-like tube 10 can be configured such that the peripheral edge portion 10B has shape retention in a bent state. For example, the core 13 may be made of a material other than polyester, or the covering 14 may be made of a material other than polypropylene, and the wire may be made of another organic material. The wire may be formed of a material other than an organic material, instead of the double layer monofilament.

In the present embodiment, as shown in fig. 4A to 4C, the peripheral edge portion 10B is formed in a band shape (band shape, flat shape). Thus, in the present embodiment, the peripheral edge portion 10B is easily bent so as to form the outer fold line and the inner fold line on the tape surface.

Fig. 5A is a development view for explaining another shape of the mesh tube 10. Fig. 5B is an enlarged perspective view of the mesh tube 10 shown in fig. 5A. The mesh tube 10 is formed by joining wires in the S direction and the Z direction (see fig. 3A and 3B), and the mesh tube 10 is a single cylindrical member having a plurality of openings 10A formed therein. Thus, the branch portion 10C may not be a joint portion.

Fig. 6A and 6B are developed views for explaining still another shape of the mesh tube 10. In the mesh-like tube 10 shown in fig. 6A, the linear peripheral edge portions 10B do not intersect, and three peripheral edge portions 10B extend in a T-shape from the branch portion 10C. In this way, the two linear peripheral edge portions 10B do not need to intersect. The mesh tube 10 shown in fig. 6B is formed of a plurality of first wires 11 formed in a spiral shape in a predetermined direction (S direction) and a plurality of second wires 12 arranged in a longitudinal direction (added in a vertical direction). In this way, when the mesh tube 10 is configured by joining the intersections of the two wires, all the wires may not be arranged in a spiral shape.

The shape of the opening 10A may be other than a square or a rectangle, or a rhombus or a parallelogram. The shape of the opening 10A may be other than a quadrangle or another polygon. The shape of the opening 10A is not limited to a polygon, and may be circular or elliptical. The opening 10A may be formed in a slit shape having no predetermined area.

Fig. 7A is an explanatory view of the shape of a braided tube as a comparative example. Fig. 7B is an enlarged explanatory view of the vicinity of the mesh of the braided tube as a comparative example. The braided tube as a comparative example was constructed by braiding wire rods into a tubular shape. The intersection points of the wires are not joined to each other, so the angle at which the wires cross each other is variable. In the case of such a braided tube, the wires are stretched in the longitudinal direction by changing the crossing angle between the wires without bending the wires. Therefore, the amount of expansion and contraction in the longitudinal direction of the braided tube is relatively small. In the case of knitting a tube, the crossing angle between the wires changes during expansion and contraction, and therefore the diameter of the tube changes. Therefore, when the braided tube is extended, the inner diameter of the braided tube becomes small, and therefore the optical fiber 5 inserted inside is pressed, which may increase the transmission loss of the optical fiber 5.

Fig. 8A and 8B are explanatory views of the state before and after expansion and contraction in the vicinity of the opening 10A (mesh) of the mesh tube 10 according to the present embodiment. In the present embodiment, when the mesh-like tube 10 is contracted in the longitudinal direction (see fig. 2B), as shown in fig. 8B, the peripheral edge portion 10B of the opening 10A is bent and folded in the longitudinal direction. This is because in the present embodiment, the peripheral edge portion 10B is bound (joined) by the branch portion 10C, and the intersection angle between the wires is not variable as in the comparative example. The curved peripheral edge portion 10B is displaced not only in the cylindrical peripheral surface of the mesh-like tube 10 before deformation but also in the radial direction. As a result, in the present embodiment, the amount of contraction in the longitudinal direction is significantly larger than that of the braided tube of the comparative example. In the present embodiment, the length of the mesh tube 10 after contraction in the longitudinal direction can be set to 10% or less of the length of the mesh tube 10 in the initial state before contraction (after expansion) (on the other hand, the knitted tube of the comparative example shown in fig. 7B cannot be contracted to 1/10 in the initial state by the contraction mechanism).

In the present embodiment, the peripheral edge portion 10B is bound (joined) by the branch portion 10C, and the intersection angle between the wires is not variable as in the comparative example, so that when the mesh-like tube 10 is elongated, the inner diameter of the mesh-like tube 10 can be suppressed from becoming excessively small. Therefore, when the mesh tube 10 in the folded state is elongated, the optical fiber 5 inserted inside can be suppressed from being pressed, and the transmission loss of the optical fiber 5 can be suppressed.

In the present embodiment, since the peripheral edge portion 10B is formed in a band shape (band-like, flat shape) (see fig. 4A), the peripheral edge portion 10B is easily bent so as to form an outer fold line and an inner fold line on the band surface, and therefore, the bent peripheral edge portion 10B is easily displaced in the radial direction, and the shrinkage in the longitudinal direction can be made extremely large. In addition, in the present embodiment, since the strength of the peripheral edge portion 10B (one-layer structure) excluding the branch portion 10C is lower than that of the branch portion 10C (two-layer structure), when the mesh-like tube 10 is folded in the longitudinal direction, the folding of the peripheral edge portion 10B can be guided so as to form an outer fold line and an inner fold line on the tape surface (so as to displace the tape surface in the radial direction).

In the present embodiment, the peripheral edge portion 10B has plasticity, and the peripheral edge portion 10B is plastically deformed in a bent state, and the peripheral edge portion 10B is held in a bent shape. That is, in the present embodiment, the peripheral edge portion 10B has shape retention in a curved state. Thus, in the present embodiment, as shown in fig. 1A, the shape of the mesh-like tube 10 can be maintained in a state where the mesh-like tube 10 is contracted in the longitudinal direction. In the present embodiment, the curved peripheral edge portion 10B can be extended so as to be restored. Thus, in the present embodiment, as shown in fig. 1C and 2A, the mesh-like tube 10 can be extended in the longitudinal direction from a state in which the mesh-like tube 10 is contracted in the longitudinal direction (see fig. 1A). In addition, in the present embodiment, the operation of inserting the optical fiber 5 into the mesh-like tube 10 is facilitated by the nature of restoring and extending the bent peripheral edge portion 10B.

Tubular member 22

The tubular member 22 (see fig. 1A to 1C) is a hollow cylindrical member (tube) and allows a bundle of the optical fibers 5 to pass therethrough. In the following description, one end of the tubular member 22 may be referred to as a "first end 22A", and the other end may be referred to as a "second end 22B". A mesh tube 10 folded in the longitudinal direction is disposed on the outer periphery of the tubular member 22. Further, a pair of cylindrical members 24 (rings) are disposed on the outer periphery of the tubular member 22.

The tubular member 22 is inserted through the folded mesh tube 10. That is, the tubular member 22 is disposed inside the mesh tube 10 of the protective unit 20, and the folded mesh tube 10 is disposed on the outer periphery of the tubular member 22. By disposing the tubular member 22 inside the mesh tube 10, the end 5A of the optical fiber 5 can be hooked to the mesh tube 10 when the optical fiber 5 is inserted into the mesh tube 10. Therefore, the tubular member 22 serves as a jig for inserting the optical fiber 5 through the mesh tube 10. In the present embodiment, it is particularly advantageous to dispose the tubular member 22 inside the mesh tube 10 in order to insert the bundle of the plurality of optical fibers 5 into the folded mesh tube 10 (described later).

The tubular member 22 is longer than the folded mesh tube 10. Further, both ends of the tubular member 22 extend from both side end portions 10X of the folded mesh tube 10.

Cylindrical member 24

The tubular member 24 (see fig. 1A to 1C) is a hollow cylindrical member (ring) shorter than the tubular member 22, and allows the bundle of optical fibers 5 and the tubular member 22 to pass therethrough. Therefore, the tubular member 24 serves as a jig for inserting the optical fiber 5 into the mesh tube 10 together with the tubular member 22. The cylindrical member 24 has an inner diameter larger than the outer diameter of the tubular member 22. Therefore, the tubular member 22 can be inserted inside the tubular member 24 and the tubular member 24 can be slid in the longitudinal direction of the tubular member 22. At the portion where the tubular member 24 is disposed in the protection unit 20, the tubular member 22 is disposed inside, and the tubular member 24 is disposed on the outer periphery of the tubular member 22. The tubular member 24 of the protection unit 20 can be removed from the tubular member 22 by sliding the tubular member 24.

The cylindrical members 24 are attached to both ends of the mesh pipe 10. Therefore, the protection unit 20 has a pair of cylindrical members 24. In the following description, one tubular member 24 is sometimes referred to as a "first tubular member 24A", and the other tubular member 24 is sometimes referred to as a "second tubular member 24B". By removing the tubular member 24 from the tubular member 22, the mesh tube 10 in the folded state can be extended on the outer periphery of the tubular member 22 (see fig. 1C).

In the state shown in fig. 1, the first cylindrical member 24A and the second cylindrical member 24B are spaced apart from each other by a shorter distance than the tubular member 22. The first end 22A of the tubular member 22 extends from an outer end of the first cylindrical member 24A, and the second end 22B of the tubular member 22 extends from an outer end of the second cylindrical member 24B. Thus, by inserting the optical fiber 5 into the tubular member 22, the optical fiber 5 can be inserted into the cylindrical member 24 (the first cylindrical member 24A and the second cylindrical member 22B) and the mesh tube 10.

Fig. 9 is a perspective view of the tubular member 24. The tubular member 24 has a tubular portion 241 and a projection 242. In the figure, the X direction, the Y direction, and the Z direction are shown, with the direction in which the pair of protrusions 242 protrude being the X direction, the axial direction of the cylindrical tube 241 being the Z direction, and the direction perpendicular to the X direction and the Z direction being the Y direction.

The tube 241 is a main body of the tubular member 24 and is a hollow cylindrical portion. The bundle of optical fibers 5 and the tubular member 22 can be passed through the inside of the cylindrical portion 241. The inner diameter of the cylindrical portion 241 is larger than the outer diameter of the tubular member 22. A projection 242 is formed on the outer periphery of the cylindrical portion 241.

The projection 242 projects outward from the outer periphery of the tube 241. In the present embodiment, the pair of projections 242 project outward in the X direction from the outer periphery of the cylindrical portion 241. Therefore, the width W of the pair of protrusions 242 in the X direction (the dimension of the cylindrical member 24 in the X direction at the portion where the protrusions 242 are formed) is larger than the outer diameter D of the cylindrical portion 241.

In the present embodiment, the projection amount of the projection 242 in the Y direction is smaller than the projection amount in the X direction. In the present embodiment, since the projection 242 hardly projects in the Y direction, the dimension H in the Y direction of the cylindrical member 24 at the portion where the projection 242 is formed is substantially the same as the outer diameter D of the cylindrical portion 241. In other words, the dimension H of the projection 242 in the Y direction (the width of the projection 242 in the Y direction) is substantially the same as the outer diameter D of the tube 241. Thus, when two cylindrical members 24 are superposed in the Y direction (described later), the total size of the two cylindrical members 24 superposed in the Y direction can be suppressed.

The protrusion 242 is formed in a thin plate shape. Therefore, the thickness T of the protrusion 242 (the dimension of the protrusion 242 in the Z direction) is relatively small (thin). A notch is formed at the edge of the protrusion 242. By forming the cutout portion, the edge of the protrusion 242 has irregularities. By forming the projections and depressions on the edges of the projection 242, the end 10X of the mesh-like tube 10 is easily hooked on the projection 242, and the cylindrical member 24 is easily attached to the end 10X of the mesh-like tube 10.

As will be described later, the projection 242 is used to fix the end 10X of the mesh-like tube 10 to another member (the storage tray 42, the branching unit 50, and the like, which will be described later). In other words, the protrusion 242 serves as a fixing portion for fixing the cylindrical member 24 to another member (the cylindrical member 24 serves as a jig for fixing the end portion of the optical fiber unit 3 (the end portion 10X of the mesh tube 10)). The end of the mesh-like tube 10 is fixed to another member (the storage tray 42, the branching unit 50, and the like described later) by inserting the protrusion 242 into a groove (a groove 471 and a groove 53A described later) of another member. The projection 242 can also be used to fix (hook) the end 10X of the mesh pipe 10 to the cylindrical member 24. In other words, the projection 242 serves as a fixing portion for fixing the end 10X of the mesh-like tube 10 to the tubular member 24.

In the present embodiment, the end portion 10X of the mesh-like tube 10 is covered with the pair of projections 242, whereby the mesh-like tube 10 is hooked on the projections 242, and the end portion 10X of the mesh-like tube 10 is heated, whereby the cylindrical member 24 and the end portion 10X of the mesh-like tube 10 are fusion-joined. The method of attaching the cylindrical member 24 to the end 10X of the mesh pipe 10 is not limited to this. For example, the cylindrical member 24 may be attached to the end 10X of the mesh pipe 10 using an adhesive or an adhesive tape. Further, the cylindrical member 24 may be attached to the end 10X of the mesh-like tube 10 by merely hooking the mesh-like tube 10 to the protrusion 242 without using an adhesive, an adhesive tape, or the like.

< method for manufacturing protection unit 20 >

Fig. 10A to 10D are explanatory views of a method for manufacturing the protection unit 20.

First, as shown in fig. 10A, a mesh-like tube 10 having a tubular member 24 attached to both ends thereof and a tubular member 22 are prepared. As shown in fig. 10B, the tubular member 22 is inserted into the first cylindrical member 24A and the mesh tube 10, and the first cylindrical member 24A is temporarily fixed to the end of the tubular member 22. Next, as shown in fig. 10C, the mesh-like tube 10 is pulled toward the first cylindrical member 24A, whereby the mesh-like tube 10 is folded in the longitudinal direction (the mesh-like tube 10 is contracted in the longitudinal direction). This allows the folded mesh tube 10 to be disposed on the outer periphery of the tubular member 22. Then, as shown in fig. 10D, the mesh tube 10 is folded in the longitudinal direction and contracted until the second cylindrical member 24B (the cylindrical member 24 attached to the end 10X on the opposite side of the mesh tube 10) is positioned on the outer periphery of the tubular member 22. Thereby, the protection unit 20 shown in fig. 1A can be manufactured.

< method for protecting optical fiber 5 Using protection Unit 20 >

Fig. 11A to 11E are explanatory diagrams of a method of protecting the optical fiber 5 using the protection unit 20. The same drawing is an explanatory drawing of a method of laying the optical fiber 5 using the protection unit 20.

First, the worker prepares the protection unit 20 and the optical fiber 5 to be protected. Here a plurality of optical fibres 5 are led out from the cable 1. As shown in fig. 11A, the operator inserts the end 5A of the bundle of optical fibers 5 into the first end 22A of the tubular member 22.

Next, the operator slides the protection unit 20 toward the lead-out portion of the optical cable 1 (at the time of separation) while inserting the optical fiber 5 through the tubular member 22 of the protection unit 20, and as shown in fig. 11B, brings the first end 22A of the tubular member 22 of the protection unit 20 to the vicinity of the time of separation of the optical cable 1. By inserting the optical fiber 5 into the tubular member 22, the optical fiber 5 can be inserted into the folded mesh tube 10 (and the cylindrical member 24), and therefore, the optical fiber 5 does not need to be hooked to the mesh tube 10. Therefore, the operation of inserting the optical fiber 5 into the mesh-like tube 10 is easier than the case of directly inserting the optical fiber 5 into the mesh-like tube 10.

However, in the present embodiment, the mesh-like tube 10 is folded in the longitudinal direction by bending the peripheral edge portion 10B of the opening 10A (see fig. 8B), and therefore the amount of contraction in the longitudinal direction of the mesh-like tube 10 is extremely large (see fig. 2B and 10D). Therefore, in the present embodiment, the length of the mesh tube 10 and the length of the protection unit 20 are sufficiently shorter than the length of the optical fiber 5 to be protected. As a result, as shown in fig. 11A, the end portion 5A of the optical fiber 5 protrudes from the second end 22B of the tubular member 22 immediately after the end portion 5A of the optical fiber 5 is inserted into the first end 22A of the tubular member 22. Therefore, when the protection unit 20 is slid toward the lead-out portion (at the time of peeling) of the optical fiber 5 (from the state of fig. 11A to the state of fig. 11B), the operator can hold the optical fiber 5 protruding from the second end 22B of the tubular member 22 with his hand and move the mesh-like tube 10 (and the tubular member 22) while pulling the optical fiber 5. Thus, in the present embodiment, the work of moving the protective tube to the root of the optical fiber 5 (in this case, to the leading portion of the optical cable 1 (at the time of stripping)) is facilitated. If the optical fiber 5 is inserted into a protective tube (for example, a long silicon tube or polyethylene tube: hereinafter, sometimes referred to as a "silicon tube or the like") having a length similar to that of the optical fiber 5 to be protected, the optical fiber 5 is less likely to protrude from the outlet of the protective tube, and therefore, the work of covering the protective tube to the root of the optical fiber 5 is difficult. In contrast, in the present embodiment, the mesh-like tube 10 having a very large shrinkage amount in the longitudinal direction is used, and the optical fiber 5 only needs to be inserted into the short mesh-like tube 10 and the tubular member 22, so that the workability can be improved.

Next, the operator removes the temporarily fixed first tubular member 24A from the tubular member 22, and draws out the first tubular member 24A to the outside of the first end 22A of the tubular member 22 as shown in fig. 11C. Since the end portion 10X of the mesh tube 10 is attached to the first cylindrical member 24A, when the first cylindrical member 24A is pulled out from the first end 22A of the tubular member 22, the end portion 10X of the mesh tube 10 is also pulled out from the first end 22A of the tubular member 22. In the present embodiment, since the tubular member 24 (first tubular member 24A) is attached to the end portion 10X of the mesh-like tube 10, the end portion 10X of the mesh-like tube 10 can be easily pulled out from the end portion (first end 22A) of the tubular member 22, as compared with the case where the tubular member 24 is not provided. Further, the operator fixes the first cylindrical member 24A drawn out from the tubular member 22 near the drawn-out portion of the optical cable 1. The first cylindrical member 24A is fixed to the optical cable 1 by an adhesive tape, for example. However, the operator who holds the protection unit 20 with the right hand may fix (temporarily fix) the first cylindrical member 24A to the optical cable 1 by holding the first cylindrical member 24A and the lead-out portion of the optical cable 1 with the left hand.

Next, as shown in fig. 11D, the operator slides the tubular member 22 toward the end 5A of the optical fiber 5. At this time, since the optical fiber 5 passes through the inside of the tubular member 22 and the first cylindrical member 24A is fixed to the lead-out portion of the optical cable 1, the mesh tube 10 is pulled out from the first end 22A of the tubular member 22. As a result, the mesh tube 10 in the folded state is extended, and as shown in fig. 2A, the bundle of optical fibers 5 is inserted into the extended portion of the mesh tube 10.

Finally, as shown in fig. 11E, the operator slides the tubular member 22 to the outside of the end 5A of the optical fiber 5, and removes the tubular member 22 from the bundle of optical fibers 5. At this time, the second cylindrical member 24B temporarily fixed to the tubular member 22 is removed from the tubular member 22, and the tubular member 22 is separated from the mesh tube 10. As shown in the drawing, the second tubular member 24B is attached to the end 10X of the mesh tube 10.

The rack 40, the storage tray 42, and the branch unit 50

< support 40 >

Fig. 12 is an explanatory view of the state inside the holder 40.

The first optical cable 1A and the second optical cable 1B are guided into the holder 40. The plurality of optical fibers 5 of the first optical cable 1A and the plurality of optical fibers 5 of the second optical cable 1B are connected to each other, and the connection portions of the plurality of optical fibers 5 are housed in the rack 40 (specifically, the housing tray 42). In the present embodiment, the optical fiber 5 of the first optical cable 1A and the optical fiber 5 of the second optical cable 1B are fusion-spliced, and the holder 40 is configured as a fusion-splice holder that houses a plurality of fusion-spliced portions. The holder 40 may be an end-forming holder for connecting the optical fibers 5 to each other by connectors (in this case, connectors are attached to the end portion 5A of the optical fiber 5 of the first optical cable 1A and the end portion 5A of the optical fiber 5 of the second optical cable 1B, respectively, and the optical fibers 5 are connected to each other by the connectors.

In the present embodiment, the optical fibers 5 drawn out from the first optical cable 1A and the second optical cable 1B are routed in the holder 40 in a state of being inserted through the mesh tube 10. In the holder 40, the optical fibers 5 led out from the first optical cable 1A and the second optical cable 1B are protected by the mesh tube 10. In the following description, a member for inserting the bundle of optical fibers 5 of the first optical cable 1A into the mesh tube 10 is sometimes referred to as a "first optical fiber unit 3A", and a member for inserting the bundle of optical fibers 5 of the second optical cable 1B into the mesh tube 10 is sometimes referred to as a "second optical fiber unit 3B".

The rack 40 includes a storage rack 41 and a branching unit 50. As shown in fig. 12, a plurality of storage shelves 41 are arranged in the vertical direction in the rack 40, and a branch unit 50 is arranged beside each storage shelf 41. Only the routing of the first fibre units 3A between a group of one branching unit 50 and one receiving rack 41 is depicted in fig. 12 (in practice a plurality of first fibre units 3A are routed within the rack 40). In addition, only one set of wiring for the second fiber units 3B of one storage rack 41 is depicted in the figure (actually a plurality of second fiber units 3B are wired within the rack 40).

Fig. 13 is a perspective view of the storage rack 41 and the branching unit 50.

The storage rack 41 is a rack provided with a plurality of (here, 6) storage trays 42. The bundle of optical fibers 5 (a plurality of optical fibers 5) of the first optical cable 1A and the bundle of optical fibers 5 (a plurality of optical fibers 5) of the second optical cable 1B are introduced into each housing tray 42. In the present embodiment, the first optical fiber unit 3A and the second optical fiber unit 3B are introduced into the respective storage trays 42. The plurality of optical fibers 5 of the first optical cable 1A and the plurality of optical fibers 5 of the second optical cable 1B are fusion-spliced, and the fusion-spliced portions are stored in the storage tray 42.

The storage rack 41 is provided with a front panel. When the front panel is opened, the storage tray 42 can be drawn out from the storage rack 41.

In the following description, each direction is defined as shown in the drawing. That is, the vertical direction is defined as the "up-down direction", and the "up" and "down" are defined according to the direction of gravity. The direction in which the storage tray 42 is drawn in and out from the storage rack 41 is referred to as the "front-rear direction", one side from which the storage tray 42 is drawn out is referred to as the "front", and the opposite side is referred to as the "rear". The direction perpendicular to the up-down direction and the front-rear direction is referred to as the "left-right direction", the right-hand side when the storage tray 42 is viewed from the front side is referred to as the "right", and the opposite side is referred to as the "left". The arrangement direction of the plurality of storage trays 42 of the storage rack 41 is the "up-down direction". The tray surface of the storage tray 42 is a surface perpendicular to the vertical direction and parallel to the front-rear direction and the left-right direction.

< storage tray 42 >

Fig. 14 is a perspective view of the storage tray 42.

The housing tray 42 is a tray housing the excess length of the optical fiber 5. The storage tray 42 is a shallow and flat-bottomed storage member composed of a bottom plate 421, side plates 422, a front plate 423, and a rear plate 424. The bottom plate portion 421 is a portion constituting a tray surface (placement surface) of the storage tray 42, and is a portion on which the storage items (the optical fibers 5 and the optical fiber units 3) are placed. The side plate portion 422, the front plate portion 423, and the rear plate portion 424 are formed to extend upward from the edge of the bottom plate portion 421. The side plate portions 422, the front plate portion 423, and the rear plate portion 424 are plate-shaped portions that prevent the stored items (the optical fibers 5 and the optical fiber units 3) from falling off.

The height of the front plate portion 423 and the rear plate portion 424 is substantially the same as the height of the storage tray 42. On the other hand, the height (the vertical dimension) of the side plate portion 422 is lower than the height (the height of the front plate portion 423 and the rear plate portion 424) of the storage tray 42. Thus, when the plurality of storage trays 42 are arranged in the vertical direction on the storage rack 41, a gap is formed in the side surface of the storage tray 42. The gap serves as a passage for introducing the optical fiber unit 3 into the storage tray 42 (see fig. 13).

The rear plate portion 424 has a folded portion 424A. The folded portion 424A is a plate-shaped portion extending from the upper edge of the rear plate portion 424 toward the front side. The folded portion 424A is disposed to face the bottom plate portion 421, and a part of the optical fiber unit 3 can be disposed between the folded portion 424A and the bottom plate portion 421. By disposing a part of the optical fiber unit 3 between the folded portion 424A and the bottom plate portion 421, the posture of the optical fiber unit 3 stored in the storage tray 42 can be stabilized. When the optical fiber unit 3 is bent, for example, in an 8-shape (or U-shape) and stored in the unit storage section 44 (described later), a part of the optical fiber unit 3 is disposed between the folded portion 424A and the bottom plate 421, and therefore the stored optical fiber unit 3 is less likely to fall off due to the folded portion 424A.

In the present embodiment, the storage tray 42 can be taken out from the storage rack 41. The storage tray 42 can be attached to and detached from the storage rack 41, and thus the work of storing the optical fiber 5 and the optical fiber unit 3 in the storage tray 42 is facilitated.

The storage tray 42 of the present embodiment includes: an optical fiber housing section 43, a unit housing section 44, a partition section 45, a connecting section 46, and a holding section 47.

The optical fiber storage portion 43 is a storage portion that stores the excess length of the optical fiber 5. The optical fiber housing 43 houses a bundle (a plurality of optical fibers 5) of the optical fibers 5 of the first optical fiber cable 1A, a bundle (a plurality of optical fibers 5) of the optical fibers 5 of the second optical fiber cable 1B, and a plurality of fusion-spliced portions. In other words, the optical fiber storage section 43 stores a plurality of fusion-spliced portions, and the excess length of the optical fiber 5 fused by the fusion-spliced portions. The fiber storage section 43 is provided with a holder section 431 for holding the fusion-spliced section and a guide section 432 for guiding the optical fiber 5.

The unit housing portion 44 is a housing portion that houses the excess length of the optical fiber unit 3. The unit housing portion 44 houses the first optical fiber unit 3A and the second optical fiber unit 3B. In other words, the excess lengths of the first optical fiber unit 3A and the second optical fiber unit 3B are stored in the optical fiber storage section 43.

However, since the mesh-like tube 10 of the present embodiment is configured such that the peripheral edge portion 10B (the peripheral edge portion 10B surrounding the opening portion 10A) can be bent and folded in the longitudinal direction, and the optical fiber unit 3 is configured such that the optical fiber 5 is inserted through the mesh-like tube 10, the optical fiber unit 3 of the present embodiment is a flexible structure that is relatively easy to bend, compared to the optical fiber unit 3 in which the optical fiber 5 is inserted through a long silicon tube or the like. Therefore, in the present embodiment, the excess length of the optical fiber unit 3 introduced into the storage tray 42 can be bent, for example, in an 8-shape (or U-shape) and stored in the unit storage portion 44. Further, when the optical fiber unit 3 is configured by inserting the optical fiber 5 through a long silicon tube or the like, the rigidity of the silicon tube or the like is higher than that of the mesh-like tube 10, and it is difficult to bend the optical fiber unit 3, so that it is difficult to store the optical fiber unit 3 in the unit storage section 44.

The partition 45 is a portion that partitions the fiber housing 43 and the unit housing 44. The space on the front side of the partition 45 (the space between the partition 45 and the front plate 423) serves as the optical fiber housing section 43, and the space on the rear side of the partition 45 (the space between the partition 45 and the rear plate 424) serves as the unit housing section 44. The partition 45 has a connecting portion 46.

The connection portion 46 is a portion (connection path; passage) connecting the optical fiber housing portion 43 and the unit housing portion 44. The connecting portion 46 is a portion formed to penetrate the partition portion 45 in the front-rear direction. The optical fiber 5 is routed between the optical fiber housing section 43 and the unit housing section 44 through the connection section 46. The connection portion 46 is formed in a groove shape, and is open at the upper side. Thereby, the optical fiber 5 is entered into the connection portion 46 from above, and the optical fiber 5 is routed between the optical fiber housing portion 43 and the unit housing portion 44. In the present embodiment, the cylindrical member 24 is inserted into the connection portion 46 from above, and the optical fiber 5 inserted through the cylindrical member 24 is routed between the fiber housing portion 43 and the unit housing portion 44. In the present embodiment, two cylindrical members 24 can be arranged in a state in which the connecting portions 46 are arranged vertically.

In the present embodiment, two connecting portions 46 are formed in the partition portion 45. One connection portion 46 is used for wiring of the optical fiber 5 of the first optical fiber unit 3A, and the other connection portion 46 is used for wiring of the optical fiber 5 of the second optical fiber unit 3B. Two connecting portions 46 are formed at each of the left and right ends of the partition portion 45. This can smooth the bending of the optical fiber unit 3 housed in the unit housing portion 44. If the connection portion 46 is formed at the center portion (the center portion in the left-right direction) of the partition portion 45, the optical fiber unit 3 needs to be sharply bent in the vicinity of the connection portion 46. Therefore, the connecting portion 46 is preferably formed at the end portion of the partition portion 45 in the left-right direction.

The connecting portion 46 is formed with a holding portion 47. The holding portion 47 is a portion for holding the cylindrical member 24 of the protection unit 20 (the cylindrical member 24 attached to the end portion 10X of the mesh-like tube 10). In the present embodiment, the holding portion 47 can hold the two tubular members 24 in a vertically aligned state. The holding portion 47 may hold one cylindrical member 24, or may hold two or more cylindrical members 24. By providing the holding portion 47, the end portion of the optical fiber unit 3 (the bundle of optical fibers 5 inserted into the mesh-like tube 10) can be fixed to the housing tray 42, and the optical fibers 5 housed in the optical fiber housing portion 43 (the optical fibers 5 extending from the optical fiber unit 3) can be suppressed from moving.

Fig. 15A is an enlarged perspective view of the holding portion 47. Fig. 15B is a diagram showing a state in which the cylindrical member 24 is held by the holding portion 47.

The holding portion 47 has a groove 471. The groove 471 is formed along the vertical direction on the left and right side surfaces of the connection portion 46. The protrusion 242 of the tubular member 24 is inserted into the groove 471. The protrusion 242 of the tubular member 24 is inserted into the groove 471, whereby the tubular member 24 is fixed to the holding portion 47.

The holding portion 47 has a pair of lower claw portions 472 and a pair of upper claw portions 473.

The lower claw 472 is a portion (pressing portion) that suppresses the lower cylindrical member 24 from coming off the holding portion 47. The pair of lower claws 472 are arranged to press the upper side of the cylindrical portion 241 of the cylindrical member 24 attached to the connecting portion 46. The distance between the pair of lower claw portions 472 in the left-right direction is preferably smaller than the outer diameter of the cylindrical portion 241 of the cylindrical member 24. Further, the pair of lower claw portions 472 is preferably elastically deformed so as to expand the interval in the left-right direction.

The upper claw 473 is a portion (pressing portion) that suppresses the upper cylindrical member 24 from coming off the holding portion 47. The pair of upper claw portions 473 presses the upper side of the cylindrical portion 241 of the upper cylindrical member 24. The distance between the pair of upper claw portions 473 in the left-right direction is preferably smaller than the outer diameter of the cylindrical portion 241 of the cylindrical member 24. Further, the pair of upper claw portions 473 is preferably elastically deformed so as to expand the interval therebetween in the left-right direction.

In the present embodiment, the lower claw 472 and the upper claw 473 form a pressing portion that presses the cylindrical member 24 from above (in the direction in which the protrusion 242 is inserted into the groove 471). The pressing portion for pressing the tubular member may not be claw-shaped. In the present embodiment, two pressing portions (the lower claw portion 472 and the upper claw portion 473) are formed vertically, but the number of the pressing portions provided to the holding portion 47 is not limited to two.

In the present embodiment, the optical fiber housing unit 48 is disposed on the front side of the housing tray 42, and the optical fiber housing portion 43 and the unit housing portion 44 are formed. The optical fiber housing unit 48 is a member in which the optical fiber housing portion 43, the partition portion 45, and the connection portion 46 are integrally molded with resin. The method of forming the optical fiber storage section 43 and the unit storage section 44 on the storage tray 42 is not limited to this. The unit housing portion 44 may be integrally molded with the optical fiber housing portion 43 by resin. The fiber storage section 43 and the unit storage section 44 may be formed by placing a resin partition section 45 on the storage tray 42 and dividing the storage space of the storage tray 42 into two by the partition section 45.

< Branch Unit 50 >

Fig. 16 is an exploded view of the branching unit 50 of the present embodiment. Fig. 17 is an exploded view of the branching unit 50 of the reference example. In fig. 16, the bundle of branched optical fibers 5 is inserted through the mesh tube 10 and the cylindrical member 24 (first cylindrical member 24A). In contrast, in the reference example of fig. 17, a long silicon tube 10' is inserted as a protective tube into the branched bundle of optical fibers 5.

The branching unit 50 is a member that branches a bundle of a plurality of optical fibers 5 from the optical cable 1. The bundle of optical fibers 5 branched from the branching unit 50 is routed between the storage trays 42 in a state of being inserted through the mesh-like tube 10 (and the cylindrical member 24). Generally, as shown in fig. 17, a bundle of optical fibers 5 is inserted through an elongated silicon tube 10' to protect the optical fibers 5. In contrast, in the present embodiment, as shown in fig. 16, the mesh-like tube 10 protects the bundle of optical fibers 5.

The branching unit 50 includes a main body portion 51 and a lid portion 57.

The main body 51 is a portion for holding the optical cable 1 and the branched bundle of optical fibers 5. The main body 51 has a first fixing portion 52, a second fixing portion 53, and a housing portion 54.

The first fixing portion 52 is a portion (cable fixing portion) for fixing the end of the optical fiber cable 1 (first optical fiber cable 1A). The first fixing portion 52 has a support portion 521 and a fastening portion. The support portion 521 is a member for supporting the optical fiber cable 1. Here, the support portion 521 is formed of a serrated plate having teeth which bite into the outer sheath of the optical fiber cable 1, but the support portion 521 may not have teeth. The support portion 521 may be formed integrally with the main body 51. The fastening member 522 is a member for fixing the optical fiber cable 1 between the supporting portion 521 and the member.

The second fixing portion 53 is a portion for fixing a protective tube (the mesh tube 10 of the present embodiment, the silicon tube 10' of the reference example) through which the bundle of optical fibers 5 is inserted. The second fixing portion 53 has a groove 53A to which a grip plate 531 (see fig. 17) can be attached. The gripping plate 531 is a metal plate having teeth biting into the silicon tube 10'. As shown in fig. 17, the gripping plate 531 has four recesses 531A, and four silicon tubes 10' can be inserted into the respective recesses 531A.

In the present embodiment, as shown in fig. 16, the grip plate 531 is not attached to the second fixing portion 53, and the protrusion 242 of the tubular member 24 is inserted into the groove 53A of the second fixing portion 53. The cylindrical member 24 is fixed to the second fixing portion 53 by inserting the protrusion 242 of the cylindrical member 24 into the groove 53A of the second fixing portion 53. In the present embodiment, the second fixing portion 53 can fix the three tubular members 24 in a vertically aligned state. One or two tubular members 24 may be fixed to the second fixing portion 53, or three or more tubular members 24 may be fixed thereto. In the present embodiment, by fixing the cylindrical member 24 to the second fixing portion 53, the end portion of the optical fiber unit 3 can be fixed to the branching unit 50 and can be moved (detached) along the mesh tube 10 through which the optical fiber 5 is inserted.

The housing portion 54 is a portion for housing a branch portion (lead-out portion; at the time of peeling) of the optical cable 1. By filling the housing 54 with an adhesive, the lead-out portion of the optical cable 1 can be adhesively fixed to the branching unit 50. After the lid 57 is attached to the body 51, the adhesive is filled into the housing 54 from the inlet 57A of the lid 57. In order to prevent leakage of the adhesive, an upstream stopper 541 is provided on the upstream side of the housing portion 54, and a downstream stopper 542 is provided on the downstream side of the housing portion 54.

In the present embodiment, the optical cable 1 has 12 bundles of optical fibers 5. In the present embodiment, after the optical cable 1 is drawn out, as shown in fig. 11A to 11E, the bundle of the optical fibers 5 is inserted through the mesh-like tube 10 and the cylindrical member 24 using the protection unit 20. In the present embodiment, when the bundle of optical fibers 5 is inserted into the mesh-like tube 10 using the protection unit 20, the cylindrical member 24 (first cylindrical member 24A) is disposed in the vicinity of the lead-out portion of the optical cable 1. Fig. 16 shows 12 first tubular members 24A (and the mesh tube 10) through which the bundle of optical fibers 5 is inserted.

In the present embodiment, the tubular member 24 (first tubular member 24A) can be fixed to the second fixing portion 53. Specifically, the cylindrical member 24 (the first cylindrical member 24A) is fixed to the second fixing portion 53 by inserting the protrusion 242 of the cylindrical member 24 from above into the groove 53A of the second fixing portion 53 with the grip plate 531 removed. The protrusions 242 of the three cylindrical members 24 arranged vertically can be inserted into the respective grooves 53A.

When the protection unit 20 of the present embodiment is used, the operation of inserting the optical fiber 5 (the operation of protecting the optical fiber 5) can be performed more easily than the case of inserting the optical fiber 5 into the elongated silicon tube 10' (see fig. 17) of the reference example. In addition, according to the present embodiment, the cylindrical member 24 of the protection unit 20 can be fixed to the second fixing portion 53 of the branch unit 50 as it is, which is convenient.

< method for laying optical fiber 5 >

Fig. 18A to 18C are explanatory views of a method of laying optical fibers 5 using the housing tray 42 according to the present embodiment. Note that, a storage method (optical fiber storage method) of storing the optical fiber 5 in the storage tray 42 is shown in the figure.

First, as shown in fig. 11A to 11E, the worker inserts the bundle of optical fibers 5 of the first optical cable 1A into the mesh tube 10 using the protection unit 20 to produce the first optical fiber unit 3A. After the first optical fiber unit 3A is produced, as shown in fig. 16, the worker inserts and fixes the first cylindrical member 24A of the mesh-like tube 10 into the second fixing portion 53, attaches the lid portion 57 to the body portion 51, fills the adhesive into the housing portion 54 from the inlet 57A of the lid portion 57, and fixes the first optical fiber cable 1A and the first optical fiber unit 3A to the branching unit 50. Although 12 first optical fiber units 3A extend from the branching unit 50, one of the first optical fiber units 3A is shown in fig. 18A. As shown in fig. 11A to 11E, the worker inserts the bundle of optical fibers 5 of the second optical cable 1B into the mesh tube 10 using the protection unit 20 to produce a second optical fiber unit 3B.

Next, as shown in fig. 18A, the worker fusion-splices the plurality of optical fibers 5 of the first optical cable 1A extending from the second cylindrical member 24B and the plurality of optical fibers 5 of the second optical cable 1B extending from the second cylindrical member 24B using a fusion-splicing device. For example, when the first optical fiber unit 3A and the second optical fiber unit 3B are each provided with 24 optical fiber ribbons of 12-core intermittent connection type, the worker takes out the optical fiber ribbons of the first optical fiber unit 3A and the second optical fiber unit 3B one by one, places them in a fusion splicer, and fusion splices the optical fibers 5 to each other.

However, in the present embodiment, the excess lengths of the first optical fiber unit 3A and the second optical fiber unit 3B can be stored in the unit storage portion 44 of the storage tray 42, and therefore the first optical fiber unit 3A and the second optical fiber unit 3B can be made longer. Therefore, in the present embodiment, the restriction on the placement position of the welding apparatus can be reduced, and the melting operation can be performed at a position away from the holder 40. Further, if the optical fiber unit 3 is configured by inserting the optical fiber 5 through the long silicon tube 10', it is difficult to bend the optical fiber unit 3, so that the optical fiber unit 3 cannot be stored in the storage tray 42, and the extra length of the optical fiber unit 3 cannot be increased, so that the melting work must be performed near the holder 40, which is inconvenient. In the present embodiment, since the fusing operation can be performed at a position remote from the holder 40, the fusing operation can be performed in parallel by a plurality of operators.

In addition, since the first optical fiber unit 3A and the second optical fiber unit 3B of the present embodiment are configured to insert the optical fiber 5 into the soft mesh tube 10, they have a soft structure that is relatively easy to bend. Therefore, in the present embodiment, the operation of placing the optical fiber in the fusion splicing device is easily performed. Further, if the optical fiber unit 3 is configured by inserting the optical fiber 5 through the silicon tube 10 ', the silicon tube 10' has high rigidity, and it is difficult to bend the optical fiber unit 3, so that the operation of placing the optical fiber 5 in the fusion splicer is inconvenient.

After the fusion splicing of the optical fiber 5, as shown in fig. 18B, the operator attaches the second cylindrical member 24B to the holding portion 47 of the storage tray 42 and stores the excess length of the optical fiber 5 in the optical fiber storage portion 43 of the storage tray 42. In the present embodiment, the excess length of the optical fiber 5 can be stored in the optical fiber storage portion 43 of the storage tray 42 in a state where the storage tray 42 is taken out from the storage rack 41, so that the storage work of the optical fiber 5 becomes easy. When the second tubular member 24B is attached to the holding portion 47 of the storage tray 42, the optical fibers 5 of the first optical fiber unit 3A and the second optical fiber unit 3B are routed to the connection portion 46 of the storage tray 42 (see fig. 14 and 15A). When the second tubular member 24B is attached to the holding portion 47 of the housing tray 42, the end portions of the first optical fiber unit 3A and the second optical fiber unit 3B are disposed in the unit housing portion 44 of the housing tray 42.

Next, as shown in fig. 18C, the operator stores the extra length of the first fiber unit 3A in the unit storage portion 44 of the storage tray 42, and also stores the extra length of the second fiber unit 3B. Further, when the second tubular member 24B is attached to the holding portion 47 of the housing tray 42 (see fig. 18B), the end portion of the optical fiber unit 3 is disposed in the unit housing portion 44 of the housing tray 42, and therefore, the operation of housing the excess length of the optical fiber unit 3 in the unit housing portion 44 is easily performed. In the present embodiment, the second tubular member 24B is fixed to the holding portion 47 of the storage tray 42, whereby the end portion of the optical fiber unit 3 is fixed, and therefore, the work of storing the excess length of the optical fiber unit 3 in the unit storage portion 44 is facilitated.

The term "summary" means that

The protection unit 20 of the present embodiment includes a mesh-like tube 10, a tubular member 22, and a cylindrical member 24 (see fig. 1A to 1C). The mesh tube 10 can have a plurality of openings 10A (meshes) formed in a mesh shape, and a plurality of optical fibers 5 can be inserted therein. Further, since the mesh-like tube 10 expands and contracts in the longitudinal direction by a large amount, the optical fiber can be easily protected during laying of the optical fiber. The tubular member 22 can be inserted into the mesh tube 10, and the plurality of optical fibers 5 can be inserted therein. By disposing the tubular member 22 inside the mesh-like tube 10, it is not necessary to hook the end 5A of the optical fiber 5 to the mesh-like tube 10 when inserting the optical fiber 5 into the mesh-like tube 10, and the optical fiber can be easily protected when laying the optical fiber. In the present embodiment, the cylindrical member 24 is attached to the end 10X of the mesh pipe 10. Thus, compared to the case where the cylindrical member 24 is not provided, the end portion 10X of the mesh-like tube 10 can be easily pulled out from the end portion (first end 22A) of the tubular member 22, and the optical fiber protection operation can be facilitated. In the above embodiment, the tubular member 24 is attached to both end portions 10X of the mesh-like tube 10, but the tubular member 24 may be attached to only one end portion 10X.

In the present embodiment, as shown in fig. 1A and 8B, the mesh-like tube 10 is folded in the longitudinal direction by bending the peripheral edge portion 10B of the opening 10A. This increases the amount of expansion and contraction in the longitudinal direction of the mesh-like tube 10, and therefore facilitates the optical fiber protection work when laying optical fibers.

In the present embodiment, as shown in fig. 1C, the tubular member 24 can be pulled out from the tubular member 22, and the mesh tube 10 in the folded state can be elongated in the longitudinal direction. This facilitates the optical fiber protection work when laying the optical fiber.

As shown in fig. 3A or 6B, the mesh-like tube 10 of the present embodiment has a structure in which a plurality of first wires 11 arranged in a predetermined direction in a spiral shape and a plurality of second wires 12 arranged in a direction different from the first wires 11 are joined to each other at intersections of the first wires 11 and the second wires 12. With this configuration, the mesh tube 10 can be easily manufactured. Further, according to this structure, the peripheral edge portion 10B is easily bent. As shown in fig. 5A, the mesh tube 10 may be formed without joining two wires.

In addition, the mesh-like tube 10 of the present embodiment is formed by fusion-bonding the intersections of the first wire 11 and the second wire 12. This enables the mesh tube 10 to be easily manufactured. In the case where the first wire 11 and the second wire 12 are fusion-bonded at their intersection, the tubular member 24 is preferably fusion-bonded to the end 10X of the mesh-like tube 10. This makes it easy to attach the end 10X of the mesh pipe 10 to the cylindrical member.

The tubular member 24 of the present embodiment includes a hollow tubular portion 241 and a projection 242 projecting outward from the outer periphery of the tubular portion 241. This facilitates the work of fixing the end 10X of the mesh-like pipe 10 using the projection 242. For example, the protrusion 242 can be used to hook the end 10X of the mesh pipe 10. The projection 242 can also be used to fix the end 10X of the mesh pipe 10 to the storage tray 42 and the branching unit 50.

As shown in fig. 9, when the projections and depressions are formed on the edge of the projection 242, the end 10X of the mesh-like tube 10 is more easily hooked on the projection 242. However, the edge of the protrusion 242 may not be formed with the unevenness. The tubular member 24 may not be provided with the projection 242. If the cylindrical member 24 is attached to the end 10X of the mesh-like tube 10 without providing the projection 242 on the cylindrical member 24, the end 10X of the mesh-like tube 10 can be easily pulled out from the end of the tubular member 22.

Description of the drawings

< Young's modulus and flexural rigidity with respect to wire >

The young's modulus and the flexural rigidity of the wire (the first wire 11 or the second wire 12) of the double-layer monofilament shown in fig. 4A were measured. Here, a double-layer monofilament strand made of an organic material was produced by using polyester as the core portion 13 and polypropylene as the covering portion 14. The cross-sectional shape of the wire rod was 0.1mm in thickness and 1mm in width. As a result of the measurement, the Young's modulus of the wire rod was about 4000N/mm²The flexural rigidity is about 0.5N/mm². The young's modulus and flexural rigidity of the wire rod were measured as follows.

The Young's modulus was measured using a tensile tester. Here, the load-tensile curve was measured by placing a test piece (wire rod) between chucks set to 200mm and setting the tensile speed to 200 mm/min. Further, the Young's modulus (unit: N/mm) of the wire rod was measured based on the measured inclination of the initial linear portion of the load-tension curve²)。

The bending stiffness was determined based on a three-point bending test. Fig. 19A is an explanatory view of a method of measuring flexural rigidity. FIG. 19B is an illustration of a load-deflection line diagram. As shown in fig. 19A, a test piece (wire rod) was placed between supporting points where the distance L was set to 30mm, and the flexural modulus of elasticity E was measured based on a three-point bending test. Here, the bending load F1 when the deflection amount became 1mm and the bending load F5 (see fig. 19B) when the deflection amount became 5mm were measured, and the flexural modulus E was measured based on the measured bending loads F1 and F5. The bending load F1 was measured using an electronic balance disposed below the fulcrum. Based on the measured flexural modulus of elasticity E (unit: Pa) and the elastic second moment I (unit: mm) of the test piece⁴) The bending stiffness EI (unit: n mm²)。

< about the shrinkage ratio Rl >

A plurality of types of protection units 20 having different numbers N of the first wires 11 and the second wires 12 (total number 2N), different inner diameters D of the mesh-like tubes 10, different spiral pitches L, and different outer diameters S of the tubular members 22 were produced. Here, the number of the first wires 11 and the second wires 12 is four (eight in total) or six (12 in total). The inner diameter D of the mesh tube 10 is set to a range of 6.3mm to 8.3 mm. The pitch L of the helix is set to 20mm to 100 mm. The outer diameter S of the tubular member 22 is set to a range of 3.5mm to 8 mm.

Fig. 20 is an explanatory diagram of the pitch P and the inner diameter D. When the number of the first wires 11 (or the second wires 12) is s and the pitch of the first wires 11 in one turn is L (mm) as shown in the drawing, the pitch P (mm) is P ═ L/s. As shown in the drawing, the inner diameter D (mm; diameter of inner diameter) is calculated as shown below, assuming that the angle (the size of the angle opened in the longitudinal direction) of the intersection of the first wire 11 and the second wire 12 is θ.

D＝L×tan(θ/2)/π

The shrinkage ratio R1 when each mesh tube 10 was shrunk in the longitudinal direction was measured. When the length (initial length) of the mesh tube 10 before the shrinkage in the longitudinal direction is L0 and the length (length during shrinkage) of the mesh tube 10 after the shrinkage in the longitudinal direction is L1, the shrinkage ratio Rl (%) is as follows.

Rl(％)＝L1/L0×100

The measurement results of the shrinkage ratio R1 of each mesh tube 10 are shown in the table below (it was confirmed that the shrinkage ratio Rl of 3 to 12% can be achieved). When each of the mesh tubes 10 is contracted in the longitudinal direction, the mesh tube 10 can be easily folded in the longitudinal direction by hand force without buckling the tubular member 22.

[ Table 1]

Total number of roots 2N (root)	12	12	12	12	8	12	12
								Inner diameter D [ mm ]]	7	8.3	8	7	6.3	7	7
Helical pitch L [ mm ]]	100	50	30	20	30	20	20
								Outside diameter S [ mm ]]	8	8	8	3.5	6	5	6
Shrinkage ratio R1 [% ]]	3	5	7	8	8.8	10	12

< mesh ratio R >

The number of the first wires 11 and the second wires 12 of the mesh tube 10 and the spiral pitch are changed to produce a plurality of kinds of mesh tubes 10 having different mesh ratios R. Here, the number of the first wires 11 and the second wires 12 is four (eight in total) or six (12 in total). The pitch of the helix is set to 50mm or 100 mm. When the ratio of the area occupied by the opening 10A on the developed surface to the total area of the mesh tubes on the developed surface (the sum of the area occupied by the opening 10A and the area occupied by the peripheral edge 10B) is defined as the mesh ratio R (%), the mesh ratio R of each mesh tube 10 is 46.2%, 55.5%, and 49.4%.

The operation of actually attaching the mesh-like tube 10 through which the bundle of optical fibers 5 is inserted to the closure is performed, and evaluation is performed based on whether or not the optical fibers 5 (optical fiber ribbon inserted through the mesh-like tube 10) or the peripheral edge portion 10B (first wire 11, second wire 12) constituting the mesh-like tube 10 are hooked on the peripheral member at the time of the attachment operation. When the hook was not hooked, the evaluation was "o (good)", and when the hook was hooked, the evaluation was "x (bad)". The evaluation results of the hooking of the peripheral members of the respective mesh pipes 10 are shown in the following table.

[ Table 2]

Total number of roots 2N (root)	12	12	8
				Helical pitch L [ mm ]]	50	100	50
Mesh ratio ` `]	46.2	55.5	49.4
				Hook peripheral parts	○	○	○

< protrusions on optical fiber >

A plurality of kinds of mesh tubes 10 having different numbers of optical fibers N, numbers of first wires 11 and second wires 12N (total number of 2N), inner diameters D of the mesh tubes 10, pitches P, and shapes of the openings 10A were produced. Here, the number of 12 intermittent coupling type optical fiber ribbons is 12 or 24, and the number of optical fibers n is 144 or 288. The number of the first wires 11 and the second wires 12 is four (eight in total) or six (12 in total). The inner diameter D of the mesh tube 10 is set to a range of 6.3mm to 8.3 mm. The pitch P is set to 8.3mm to 45mm (the pitch of the helix is 50mm to 270 mm). The shape of the opening is a rhombus, and the lengths of two diagonal lines of the rhombus are different from each other (the length of the diagonal line along the longitudinal direction (the length of the opening in the longitudinal direction) and the length of the diagonal line along the circumferential direction (the length of the opening in the circumferential direction) are shown in the table).

When each of the mesh tubes 10 was bent at a bending radius of 15mm, it was confirmed whether or not the optical fiber 5 protruded from the opening 10A of the mesh tube 10. When the mesh tube in the bent state is pulled inward (toward the bending center), it is confirmed whether or not the optical fiber 5 protrudes from the opening 10A of the mesh tube 10. The results of the presence or absence of protrusion of the optical fiber in each mesh tube 10 are shown in the following table.

[ Table 3]

Number of optical fibers n (root)	288	288	288	288	144
						Total number of roots 2N (root)	12	12	12	12	8
Inner diameter D [ mm ]]	8.3	7	7.3	7	6.3
						Pitch P [ mm ]]	8.3	17	25	45	12.5
Shape of opening part	Diamond shape	Diamond shape	Diamond shape	Diamond shape	Diamond shape
						Length of opening in longitudinal direction	6mm	14mm	18mm	35mm	5mm
Length of circumferential opening	3mm	4mm	4mm	3.5mm	3.5mm
						Prominence (when bending)	Is free of	Is free of	Is free of	Is provided with	Is free of
Prominence (when pulling)	Is free of	Is free of	Is provided with	Is provided with	Is free of

As shown in table 3, the shorter the opening length in the longitudinal direction, the more difficult it is for the optical fiber 5 to protrude from the opening 10A of the mesh tube 10. When the shape of the opening is a rhombus, the protrusion of the optical fiber 5 when the mesh-like tube 10 is bent can be suppressed as long as the opening length in the longitudinal direction is 18mm or less. In the case where the shape of the opening is a rhombus, the protrusion of the optical fiber 5 when the mesh tube 10 in the bent state is pulled can be suppressed as long as the opening length in the longitudinal direction is 14mm or less.

Next, a plurality of kinds of mesh tubes 10 having further different shapes of the openings 10A were produced. Here, the mesh-like tube 10 is formed as one cylindrical member forming the plurality of openings 10A, and the openings 10A are formed in a slit shape or a rectangular shape. In the case of the slit-shaped opening 10A, a slit is formed along the longitudinal direction, and the slit width (the length of the opening in the circumferential direction) is made smaller than 0.5 mm. The width of the peripheral edge portion 10B between the openings 10A and 10A adjacent to each other in the circumferential direction (the circumferential dimension of the peripheral edge portion 10B) is 4mm when the opening 10A is slit-shaped, and 2mm when the opening 10A is rectangular. As described above, it was confirmed whether or not the optical fiber 5 protruded from the opening 10A of the mesh-like tube 10 when the mesh-like tube 10 was bent or when the mesh-like tube 10 in the bent state was pulled inward. The results of the presence or absence of protrusion of the optical fiber in each mesh tube 10 are shown in the following table.

[ Table 4]

Number of optical fibers n (root)

288

288

288

288

288

288

Inner diameter D [ mm ]]

8

8

8

8

8

8

Pitch P [ mm ]]

12

22

42

12

22

42

Shape of opening part

Narrow slit

Narrow slit

Narrow slit

Rectangle

Rectangle

Rectangle

Length in the direction of elongation

10mm

20mm

40mm

10mm

20mm

40mm

Length of opening in circumferential direction

＜0.5mm

＜0.5mm

＜0.5mm

2mm

2mm

2mm

Prominence (when bending)

Is free of

Is free of

Is provided with

Is free of

Is free of

Is provided with

Prominence (when stretching)

Is free of

Is provided with

Is provided with

Is free of

Is provided with

Is provided with

As shown in tables 3 and 4, regardless of the shape of the opening 10A, the shorter the opening length in the longitudinal direction, the more difficult the optical fiber 5 tends to protrude from the opening 10A of the mesh tube 10. When the opening length of the opening 10A in the longitudinal direction is 20mm or less, the protrusion of the optical fiber 5 when the mesh-like tube 10 is bent can be suppressed. In addition, if the opening length of the opening 10A in the longitudinal direction is 14mm or less, the protrusion of the optical fiber 5 when the mesh-like tube 10 in the bent state is pulled can be suppressed.

< Strength of branching portion >

A plurality of kinds of mesh tubes 10 having different numbers N of first wires 11 and second wires 12 (total number 2N), inner diameters D of the mesh tubes 10, and pitches P were produced. Here, the number of the first wires 11 and the second wires 12 is four (eight in total) or six (12 in total). The inner diameter D of the mesh tube 10 is set to 6.3mm or 8.3 mm. The pitch L of the helix was set to 50 mm.

A pulling force of 180N was applied to each of the mesh-like tubes 10, and the presence or absence of separation of the first wire 11 and the second wire 12 in the branch portion 10C (the branch portion 10C where the intersection of the first wire 11 and the second wire 12 was fusion-bonded) was confirmed. The results of the presence or absence of separation of the branch portion 10C in each mesh-like tube 10 are shown in the table below (it was confirmed that the branch portion 10C was not broken by a pulling force of 180N).

[ Table 5]

Total number of roots N (root)	12	8
			Inner diameter D [ mm ]]	8.3	6.3
Helical pitch L [ mm ]]	50	50
			Presence or absence of separation	Is free of	Is free of

< bundle of mesh tubes 10 >

The outer peripheral length of a bundle of 12 optical fiber units was measured by preparing 12 optical fiber units 3 in which 288 optical fibers were inserted into a mesh tube 10 having an outer diameter of 8.3mm, bundling the 12 optical fiber units 3. For comparison, 12 polyethylene protective tubes (9.7 mm in outer diameter and 0.7mm in wall thickness) through which 288 optical fibers were inserted were prepared, and the 12 protective tubes were bundled and the outer circumferential length of the bundle of the 12 protective tubes was measured. Further, a rope is wound around the outer peripheries of the bundled 12 optical fiber units or the outer peripheries of the bundled 12 protective tubes, and the lengths of the ropes are measured, whereby the outer peripheral lengths of the respective bundles are measured. Since the optical fiber unit 3 using the mesh tube 10 is more easily deformed in cross-sectional shape than the polyethylene protective tube, the outer circumferential length of the bundle of 12 protective tubes made of polyethylene is 14mm, whereas the outer circumferential length of the bundle of 12 optical fiber units 3 using the mesh tube 10 is 10 mm.

The term "other" means

The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be changed/modified without departing from the gist thereof, and equivalents thereof are certainly included in the present invention.

Description of reference numerals

1 … optical cable, 1a … first optical cable, 1B … second optical cable, 3 … optical fiber unit, 3a … first optical fiber unit, 3B … second optical fiber unit, 5 … optical fiber, 10 … mesh tube, 10' … silicon tube, 10a … opening, 10B … peripheral edge, 10C … branch, 10X … end, 11 … first wire, 12 … second wire, 13 … core, 14 … covering, 20 … protection unit, 22 … tubular member, 22a … first end, 22B … second end, 24 … tubular member, 24a … first tubular member, 24B … second tubular member, 241 …, 242 … protrusion, 40 … support, 41 … storage rack, 42 … storage tray, 421 … bottom plate, 36422 side plate, … front plate, 36423, … rear plate, … storage rack, 36424, … storage rack, 36424, 45 … partition, 46 … connecting portion, 47 … holding portion, 471 … groove portion, 472 … lower claw portion, 473 … upper claw portion, 48 … optical fiber storage unit, 50 … branching unit, 51 … main body portion, 52 … first fixing portion, 521 … supporting portion, 522 … fastening member, 53 … second fixing portion, 53a … groove, 531 … holding plate, 531a … recess portion, 54 … storage portion, 541 … upstream side stopper, 542 … downstream side stopper, 57 … cover portion, 57a … inlet.