JP2593955Y2 - Spacer type optical fiber cable - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer type optical fiber cable in which an optical fiber ribbon is accommodated in a groove for accommodating a spacer, and more particularly to light generated by deformation of the spacer shape due to external compressive force. The present invention relates to a spacer type optical fiber cable capable of preventing cutting of a fiber ribbon and pressure on the optical fiber ribbon and reducing influence on transmission loss.

[0002]

2. Description of the Related Art Generally, an optical fiber has a remarkable difference in physical or mechanical characteristics as compared with a conventional copper conductor. The characteristics and ease of handling are improved. However, in the case of a cable, when a large external force such as lateral pressure is applied to the optical fiber core, a slight bending (microbending) occurs in the optical fiber, and the transmission loss increases. There is a need. Considering this point, there is a spacer type as a structure of the optical fiber cable. This spacer type optical fiber cable is
The structure is aimed at improving the mechanical properties of the cable, especially for high reliability against lateral pressure.

[0003] In addition, in the optical fiber drawing apparatus, the optical fiber is drawn out of an electric furnace and spun and formed. However, in this state, the surface is easily damaged and the mechanical strength is weak. At the same time, it is formed by coating with a UV-curable resin or the like. In addition, a plurality of (for example, eight) optical fiber strands are arranged, covered with an acrylate resin such as an acrylate, an acrylate or an acrylate resin, and provided with a plurality of cores. Tape-shaped core wire).

Conventionally, an optical fiber cable has a polyethylene spacer 120 having a circular cross section as shown in FIG. At the center of the spacer 120, a tensile member (tension member) 110 is provided. A plurality of storage grooves 130 having a rectangular cross section in the longitudinal direction are formed on the outer peripheral surface of the spacer 120 (four, 130 in FIG. 12).
A, 130B, 130C, 130D).
As shown in FIG. 13, optical fiber tape-shaped cores 140 (in FIG. 13, eight-core tape-shaped cores) are inserted into the storage grooves 130A, 130B, 130C, and 130D, respectively. The outside of the spacer 120 in which the optical fiber tape-shaped core wire 140 is inserted into the storage groove 130 is wound and held down by the holding winding tape 150.
Aluminum laminated tape (not shown) on this
Is wound, and a sheath (sheath) 160 is coated thereon. Thus, the optical fiber cable 100 is configured.

[0005]

However, in the conventional optical fiber cable, the optical fiber cable 1
When 00 receives an external force, for example, a compressive force,
The spacer 120 is deformed by an external compressive force as shown in FIG. Then, a compressive force due to the deformation of the spacer 120 is applied to the optical fiber tape-shaped core wire 140,
The optical fiber ribbon 140 is pressed. As described above, a large external force such as a lateral pressure is applied to the optical fiber tape-shaped core wire 140, and the optical fiber wire constituting the optical fiber tape-shaped core wire 140 is slightly bent (microbending).
This causes a problem that transmission loss is increased.

The spacer 120 is usually formed using polyethylene as a material. Therefore, when a pressure (compression force) is applied to the optical fiber cable 100 from the outside and the spacer 120 is deformed, the shape of the spacer 120 does not completely return to the original shape even after the external pressure is removed. That is, when the spacer 120 is deformed, a minute bend (microbending) is applied to the optical fiber constituting the optical fiber tape-shaped core wire 140 without disappearing, and even after the external pressure is removed. There is a problem that the increased transmission loss does not recover.

Further, in the conventional optical fiber cable, when the optical fiber cable 100 receives an external force, for example, a compressive force, the spacer 120 is deformed. 120
There is a problem that the optical fiber tape-shaped core wire 140 may be cut by the side pressure of A.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to apply pressure (compression force) to an optical fiber cable from the outside.
Spacer type that can reduce the deformation of the spacer even when is added, prevent the optical fiber tape-shaped core from being pressed by the deformation, and prevent the transmission loss of the optical fiber tape-shaped core from increasing. It is intended to provide an optical fiber cable.

[0009]

In order to achieve the above object, a spacer type optical fiber cable according to the present invention comprises:
A tensile member is disposed at the center, a spacer is disposed outside the tensile member, a plurality of storage grooves having a rectangular cross section in the longitudinal direction are formed on the outer peripheral surface of the spacer, and an optical fiber is provided in the plurality of storage grooves. In the spacer-type optical fiber cable containing the core wire, a step is formed by cutting a predetermined distance in the circumferential direction at a predetermined depth in each of the upper ends of both wall surfaces of the plurality of storage grooves, and the step is formed. A lid-like protector that fits and covers the storage groove is mounted.

[0010]

A strength member is provided at the center, a spacer is provided outside the strength member, and a plurality of storage grooves having a rectangular cross section in the longitudinal direction are formed on the outer peripheral surface of the spacer. In the spacer type optical fiber cable in which the optical fiber core is stored, a step is formed by cutting a predetermined distance in the circumferential direction at a predetermined depth in each of the upper ends of both wall surfaces of the plurality of storage grooves, Since a lid-like protector is fitted to the step portion and covers the storage groove, even if pressure (compression force) is applied to the optical fiber cable from the outside, deformation of the spacer is reduced, It is possible to prevent the optical fiber core from being pressed by the deformation, thereby preventing the transmission loss of the optical fiber core from increasing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the spacer type optical fiber cable according to the present invention will be described below. 1 to 4 show an embodiment of the spacer type optical fiber cable according to the present invention. In the figure, reference numeral 1 denotes an optical fiber cable, which is a spacer type optical fiber cable capable of improving the mechanical properties of the cable, in particular, obtaining high reliability against lateral pressure.

Reference numeral 2 denotes a tensile member (tension member), which is formed of a steel wire or a steel stranded wire. The tensile strength member 2 is for preventing the cable from being stretched by its own weight. That is, the plurality of optical fiber cores constituting the optical fiber cable are made of a brittle material. If the optical fiber cable is laid as it is, the cable expands due to its own weight, and stress is applied to the optical fiber core, resulting in residual stress. The generation of the residual stress reduces the life of the optical fiber cable. Therefore, in order to prevent such a residual stress from being generated in the optical fiber cable, in the optical fiber cable 1, a strength member 2 made of a steel wire or a steel stranded wire is used.

Reference numeral 3 denotes a spacer for accommodating a plurality of optical fibers. As shown in FIG. 1, the spacer 3 is extruded and coated on the strength member 2 so that the strength member 2 is located at the center. And this spacer 3
In general, polyethylene is used, but not limited to polyethylene, it is also possible to impart elasticity by using urethane, a rubber-based polymer material elastomer, etc. And an effect of protecting the optical fiber cable 1 from side pressure can be obtained. The outer periphery of the spacer 3 is formed in a substantially circular cross section.

Reference numeral 4 denotes a housing groove, as shown in FIG. 1, provided on the outer peripheral surface side of the spacer 3 in a plurality in the longitudinal direction of the optical fiber cable 1. In the present embodiment of FIG.
Articles, 4A to 4D are provided, but Articles 6, 8, 10
There are cases such as articles. The storage grooves 4A to 4D are formed in a rectangular cross section. 5 is a step wider than the storage groove 4,
It is formed on both sides of the upper end of the storage groove 4. This step 5
Is for fitting and storing a protector 6 described later.
It is formed wider than the width of the storage groove 4, the storage groove 4A has a step 5A, the storage groove 4B has a step 5B, the storage groove 4C has a step 5C, and the storage groove 4D has a step 5D. Are provided for each.

Reference numeral 6 denotes a protector, the upper surface of which is formed in a curved surface having the same radius of curvature as the outer peripheral surface of the spacer 3, the lower surface is formed in a planar shape, and the cover is formed in a strip-like long lid shape.
As shown in FIG. 3, the protector 6 stores a plurality of optical fiber ribbons 7 in the storage groove 4 and then covers the storage groove 4 to cover it. As described above, since the protector 6 covers the storage groove 4, the optical fiber tape-shaped core wire 7 stored in the storage groove 4 is not pressed when the protector 6 covers the storage groove 4. As described above, the step portion 5 is formed with a sufficient depth for accommodating the optical fiber ribbon 7. Reference numeral 7 denotes an optical fiber tape-shaped core wire. In an optical fiber drawing device, a plurality of optical fiber wires (the present embodiment) are formed by being drawn from an electric furnace, spinning, and simultaneously coated with a UV-curable resin or the like. In the example,
(8 pieces) It is aligned in parallel, bundled in a belt shape, and collectively coated with resin to form a tape shape. The number of the optical fiber tape-shaped cores 7 is equal to the number of lines corresponding to the number of signals to be transmitted (four in this embodiment).
It is stored in the storage groove 4. A plurality of (four in the present embodiment) optical fiber tape-shaped core wires 7 are stacked and stored in the storage groove 4, and the protector 6 is fitted into the step portion 5 and stored.
Cover the lid.

Reference numeral 8 denotes a holding tape, which is a stepped portion 5 of the storage groove 4.
This is for pressing down the protector 6 which is fitted and stored in the housing. The holding tape 8 stores the required number of optical fiber tape-shaped core wires 7 in a superimposed manner in each of the storage grooves 4A to 4D of the spacer 3, and stores the stepped portion 5 of the storage groove 4A.
A, a protector 6A, a protector 6B on the step 5B of the storage groove 4B, and a protector 6C on the step 5C of the storage groove 4C.
After the protector 6D is mounted on the step 5D of the storage groove 4D, as shown in FIG. 5, the protector 6D is wound over the protectors 6A to 6D mounted on the steps 5A to 5D of the storage grooves 4A to 4D. This holding tape 8 is applied to the spacer 3
Around the outer periphery of the storage groove 4A-4D, it is possible to prevent the protector 6A-6D from jumping out of the steps 5A-5D of the storage grooves 4A-4D. An aluminum laminated tape (not shown) is placed on the holding tape 8.
Is wrapped around. Reference numeral 9 denotes a sheath which is extruded and coated on an aluminum laminate tape as shown in FIG. The sheath 9 is made of PVC (polyvinyl chloride resin).

After accommodating a plurality of optical fiber tape-shaped core wires 7 in each of the storage grooves 4 of the spacer 3 as described above,
The optical fiber tape-shaped core wire 7 is prevented from protruding, and the storage groove 4 is formed by the side pressure applied to the optical fiber cable 1.
The protector 6 is fitted so as to cover the storage groove 4 in order to prevent the deformation. Then, the optical fiber tape-shaped core wire 7 which is fitted to the stepped portion 5 of the receiving grooves 4 is wound presser <br/> wound tape 8 so as not to jump out. Thereafter, an aluminum laminate tape (not shown) is wound thereon, and a sheath 9 is further coated thereon.

When a lateral pressure F is applied to the optical fiber cable 1 thus configured in the vicinity of the end of the protector 6 of the optical fiber cable 1, as shown in FIG. The spacer 3 jumps over the storage groove 4 and interposes on the facing step 5 and is dispersed in the circumferential direction of the spacer 3. Therefore, the deformation of the storage groove 4 of the spacer 3 can be reduced by the action of the protector 6 as compared with the conventional spacer, and the deformation of the storage groove 4 with respect to the optical fiber ribbon 7 stored in the storage groove 4 can be achieved. Compression can be reduced. That is, the optical transmission loss of the optical fiber ribbon 7 can be reduced as compared with the conventional optical fiber cable.

As shown in FIG. 8, when a lateral pressure F is applied directly from above the protector 6 of the optical fiber cable 1, the protector 6 is fitted to the step 5 formed at both upper ends of the storage groove 4. Therefore, the lateral pressure F is applied to the spacer 3 as a force in the direction of expanding the protector 6. That is, the protector 6 shown in FIG.
Side pressure F directly applied from the upper portion of the housing 3 is applied from both ends of the protector 6 to the step portions 5 formed at both upper ends of the storage groove 4 via the protector 6 and is dispersed in the circumferential direction of the spacer 3. Therefore, the deformation of the storage groove 4 of the spacer 3 can be reduced by the action of the protector 6 as compared with the conventional spacer, and the deformation of the storage groove 4 with respect to the optical fiber ribbon 7 stored in the storage groove 4 can be achieved. Compression can be reduced. That is, the optical transmission loss of the optical fiber ribbon 7 can be reduced as compared with the conventional optical fiber cable.

FIGS. 9 to 11 show other embodiments of the spacer type optical fiber cable according to the present invention. In this figure, the present embodiment is different from the embodiment shown in FIGS. 1 to 5 in that a fitting groove is provided in a longitudinal direction in a step portion 5 of a storage groove 4 of a spacer 3 and a longitudinal direction of a protector 6. The point is that fitting projections extending from both ends are formed.

That is, reference numeral 10 denotes a tensile member (tension member), similar to the tensile member 2, which is constituted by a steel wire or a steel stranded wire. Like the tensile strength member 2, the tensile strength member 10 is for preventing the cable from being stretched by its own weight. Reference numeral 11 denotes a spacer for accommodating a plurality of optical fibers. Like the spacer 3, the spacer 11 is extruded and coated on the strength member 10 so that the strength member 10 is located at the center as shown in FIG. The spacer 11 is generally made of polyethylene, but is not limited to polyethylene. It is also possible to impart elasticity by using urethane, a rubber-based polymer material elastomer, or the like.
It is also possible to use a resin made of a material that does not easily allow water to pass through, such as a resin, so that an effect of protecting the optical fiber cable against lateral pressure can be obtained. The outer periphery of the spacer 11 is formed in a substantially circular cross section.

Reference numeral 12 denotes a storage groove, as shown in FIG. 9, provided on the outer peripheral surface side of the spacer 11 in a plurality in the longitudinal direction of the spacer 11. In the embodiment shown in FIG.
As in the illustrated embodiment, there are provided four, 12A to 12D, but there may be six, eight, ten, and the like. The storage grooves 12A to 12D store the optical fiber ribbon 7 formed in a tape shape, and are formed in a rectangular cross section. 13 is a step part wider than the storage groove 12,
It is formed on both sides of the upper end of the storage groove 12. This step 1
3 is for inserting a protector 15 described later,
The storage groove 12A is formed wider than the width of the storage groove 12 and
Has a step 13A, a groove 13B has a step 13B, a groove 12C has a step 13C, and a groove 12D has a step 1A.
3D is provided for each. Reference numeral 14 denotes a fitting groove, which is provided on the lower surface side of the step portion 13 in a rectangular cross section in the longitudinal direction of the spacer 11. The fitting groove 14 is for fitting and housing a fitting protrusion 16 of a protector 15 described later.
The step 13A has two fitting grooves 14A, the step 13B has two fitting grooves 14B, and the step 13C has two fitting grooves 1A.
4C, the step portion 13D is provided with two fitting grooves 14D. As shown in FIG. 10, a protector 15 has an upper surface formed with a curved surface having the same radius of curvature as the outer peripheral surface of the spacer 11, a lower surface formed in a planar shape, and a long lid shape. Reference numeral 16 denotes a fitting projection, which is a projection having a rectangular cross section formed at both ends of the protector 15 and extending in the longitudinal direction of the protector 15. The fitting projections 16 formed at both ends of the protector 15 are configured to fit into fitting grooves 14 formed on the lower surface side of the step portion 13 as shown in FIG. In this way, as shown in FIG. 11, the protector 15 stores the plurality of optical fiber
It is to cover like a lid.

Therefore, when a lateral pressure (F) as shown in FIG. 7, for example, is applied to the cable, the lateral pressure (F) passes through the housing groove 12 via the protector 15 and the protector 1
5, the spacers 11 can be dispersed in the circumferential direction, the deformation of the storage grooves 12 can be reduced as compared with the conventional spacers, and the compression of the optical fiber ribbon 7 can be reduced accordingly. Therefore, by using the protector 15, the optical transmission loss of the optical fiber ribbon 7 can be reduced as compared with the conventional optical fiber cable. Further, when a lateral pressure (F) is applied to the cable directly from the upper part of the protector 15 as shown in FIG. 8, the lateral pressure (F) is applied via the protector 15 to the spacer 1.
Since it is dispersed in the circumferential direction of 1 and inside the spacer 11, the deformation of the storage groove 12 can be made smaller than that of the conventional spacer. Therefore, the compression of the optical fiber ribbon 7 can be reduced by that much, and the optical fiber tape 7
Can reduce the optical transmission loss of the conventional optical fiber cable.

[0024]

According to the present invention, a strength member is provided at the center, a spacer is provided outside the strength member, and a plurality of storage grooves having a rectangular cross section in the longitudinal direction are formed on an outer peripheral surface of the spacer.
A step is formed by cutting a predetermined distance in the circumferential direction at a predetermined depth into each of the upper ends of both wall surfaces of the plurality of storage grooves of the spacer type optical fiber cable in which the optical fiber core wires are stored in the plurality of storage grooves. It is formed and fitted with a lid-like protector that fits into the step and covers the storage groove. Therefore, even if pressure (compression force) is externally applied to the optical fiber cable, deformation of the spacer is prevented. By making the optical fiber core small, it is possible to prevent the optical fiber core from being pressed by deformation, thereby preventing the transmission loss of the optical fiber core from increasing.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spacer showing an embodiment of an optical fiber cable according to the present invention.

FIG. 2 is a perspective view of the protector showing the embodiment of the optical fiber cable according to the present invention.

FIG. 3 is a view showing a state where the protector shown in FIG. 2 is mounted in a storage groove of a spacer shown in FIG. 1;

FIG. 4 is a cross-sectional view showing an overall configuration of the embodiment of the optical fiber cable according to the present invention.

5 is a diagram showing a state wrapped with presser winding tape after storing the optical fiber tape-shaped core wire in the receiving groove of the spacer shown in FIG.

6 is a partially enlarged view showing a state coated with a sheath over the state of the spacer wound illustration of presser winding tape 5.

7 is a partially enlarged view showing a state in which a compressive force is applied to the optical fiber cable shown in FIG. 4 from the outside and the protector is deformed.

FIG. 8 is a partially enlarged view showing a state in which the protector is deformed when a compressive force is applied to the optical fiber cable shown in FIG. 4 from the outside toward the center of the protector from above.

FIG. 9 is a sectional view of a spacer showing another embodiment of the optical fiber cable according to the present invention.

FIG. 10 is a perspective view of a protector showing another embodiment of the optical fiber cable according to the present invention.

FIG. 11 is a view showing a state where the protector shown in FIG. 10 is mounted in the storage groove of the spacer shown in FIG. 9;

FIG. 12 is a sectional view of a spacer of a conventional optical fiber cable.

FIG. 13 is a sectional view of a conventional optical fiber cable.

FIG. 14 is a diagram showing a state in which a spacer is deformed by applying a slight compressive force from the outside to a conventional optical fiber cable.

[Explanation of symbols]

1 …………………………………………………………………………………………………………………………………………………………………………………… Tensile strength 3,11 …………………………………… Spacer 4,12 ……………………………………………… Groove 5,13 ……………………………………………………… 6,15 …………………………………… Protector 7 …………………………………………………………………………………………………………………………………………………………………… … Holding tape 14 ……………………………… Fitting groove 16 ………………………………………… …………… Mating protrusion

Claims (1)

(57) [Scope of request for utility model registration] 1. A strength member is provided at the center, a spacer is provided outside the strength member, and a plurality of storage grooves having a rectangular cross section in the longitudinal direction are formed on an outer peripheral surface of the spacer. In the spacer type optical fiber cable in which the optical fiber tape-shaped core wire is stored in the storage groove, a step is formed by cutting a predetermined depth in a circumferential direction at a predetermined depth in each of the upper ends of both wall surfaces of the plurality of storage grooves. A spacer-type optical fiber cable comprising a cover-shaped protector formed and fitted to the step to cover the storage groove.