JPH08220394A - Optical cable - Google Patents

Abstract

(57) [Abstract] [Purpose] When an optical cable is branched at an intermediate portion, a desired optical fiber can be taken out without causing another optical fiber to jump out. [Structure] A grooved spacer 2 covered with an outer cover 1 has a plurality of grooves 3 around which a groove direction is reversed at regular intervals. An optical fiber is accommodated in each groove. Around the grooved spacer 2, a plurality of filaments or strips 5 are provided over the entire circumference along the longitudinal direction of the optical cable. These are fixed by welding or adhesion at the portion in contact with the outer circumference of the grooved spacer 2 to suppress the optical fiber. The desired optical fiber 4a can be taken out by cutting the filament or strips 5a, 5b holding the optical fiber 4a to be taken out at the upper part of the groove.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable that accommodates a plurality of optical fibers, and an optical cable in which an arbitrary optical fiber can be easily taken out from an intermediate portion and branched.

[0002]

2. Description of the Related Art In recent years, in order to improve the use efficiency of optical fibers in optical cables, there are cases in which the optical cables are branched from the middle of the optical cables for use. Therefore, it is necessary to take out the optical fiber. Conventionally, as an optical cable in which an optical fiber can be easily taken out from an intermediate portion, an SZ slot type optical cable is known, for example, in Japanese Patent Laid-Open No. 63-301911. This optical cable has a structure in which the rotation directions of a plurality of spiral grooves carved in a grooved spacer are reversed at a constant cycle, and an optical fiber is housed in the plurality of spiral grooves. On the outside of the grooved spacer, there is a coating layer formed by extrusion coating with a synthetic resin, and a layer under which a press winding or aluminum layer made of, for example, a non-woven fabric is provided. Call it the jacket. That is, it can be said that the structure in which the optical fiber is housed in the SZ slot and the outer cover is provided thereon is known.

However, in recent years, an optical cable having an unnecessary optical fiber accommodated at the time of installation has been installed, and when the need arises, the excessive optical fiber is branched and used from the middle of the optical cable. Is being done. In such branching work, while some optical fibers in the optical cable are used for transmission,
The optical fiber is taken out. The conventional optical cable has a problem that when the jacket is removed by branching work, not only the specific optical fiber to be taken out but also the optical fiber currently in use pops out at the inversion portion of the groove. If this protruding optical fiber comes into contact with a nearby object, it will cause loss fluctuations in the optical signal being transmitted, which will cause deterioration such as code errors at the receiving point of the optical fiber being used, and cause obstacles. Becomes

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and when an optical wiring cable is branched at an intermediate portion, another optical fiber is not ejected and a desired optical fiber is not projected. It is an object of the present invention to provide an optical cable capable of taking out a cable.

[0005]

According to a first aspect of the present invention, there is provided a grooved spacer having a plurality of grooves on the outer circumference, the groove directions of which are reversed at regular intervals, and a light beam accommodated in the groove. An optical cable having a fiber and an outer cover that covers the grooved spacer is characterized by having a pop-out prevention member that locally seals the opening of the groove.

According to a second aspect of the present invention, in the first aspect of the present invention, the protrusion preventing member is a linear member provided around the spacer with groove along the longitudinal direction of the optical cable. It is a band-shaped body, and is characterized in that it is integrated with the grooved spacer at a portion in contact with the outer periphery of the grooved spacer.

According to a third aspect of the present invention, in the first aspect of the invention, the pop-out preventing member is a linear member or tape wound around the grooved spacer, and the grooved spacer is used. It is characterized in that it is integrated with the grooved spacer at the portion in contact with the outer periphery of the.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the protrusion preventing member is an annular member provided in the vicinity of the reversing portion, and is a portion contacting the outer periphery of the grooved spacer. It is characterized by being integrated with the grooved spacer.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the protrusion preventing member is braided around the grooved spacer and is connected to each other at a crossing portion of the braid. It is characterized in that it is a reticulated body composed of a body or a band.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the protrusion preventing member is provided in the vicinity of the reversing portion, projects from the side edge of the groove, and has a width of the opening portion. It is a claw-shaped member that covers the opening so as to be smaller than the diameter of the optical fiber.

According to a seventh aspect of the present invention, in the first aspect of the invention, the pop-out prevention member is provided in the vicinity of the reversing portion, and projects from the inner side edge of the groove to the outer side edge to form an opening. It is a claw-shaped member that covers.

According to an eighth aspect of the present invention, in the optical cable according to any one of the first to seventh aspects, the optical fiber housed in the groove has a distinguishable coating. Is.

According to a ninth aspect of the present invention, the optical cable according to any one of the first to eighth aspects is characterized in that it has an outer jacket.

[0014]

According to the optical cable of the first aspect, the protrusion preventing member for locally sealing the opening of the groove prevents the protrusion of the optical fiber from the inverted portion of the groove. Since this protrusion preventing member locally seals the opening of the groove, the protrusion preventing member of the optical fiber to be taken out is cut or deformed, or
Only the required optical fiber can be taken out from the groove by removing the portion integrated with the grooved spacer. The other optical fibers are sealed by the pop-out preventing member and do not come out of the groove. Further, since the pop-out prevention member is locally provided, the optical fiber accommodated in the groove can be recognized from between the pop-out prevention members.

According to the optical cable of the second aspect, the pop-out preventing member is a linear member or a strip-shaped member provided around the grooved spacer along the longitudinal direction of the optical cable, and the outer periphery of the grooved spacer. Since it is integrated with the grooved spacer at the portion in contact with, the optical fiber alone can be taken out by removing the linear or band-shaped body of the groove from which the optical fiber is to be taken out.

According to the optical cable of the third aspect, the pop-out preventing member is a linear member or tape wound around the grooved spacer, and is integral with the grooved spacer at a portion in contact with the outer periphery of the grooved spacer. The optical fiber can be taken out only by removing the linear body or the band-shaped body of the groove from which the optical fiber is taken out by cutting the optical fiber.

According to the optical cable of the fourth aspect, the pop-out preventing member is an annular member provided in the vicinity of the reversing portion, and is integrated with the grooved spacer at the portion in contact with the outer periphery of the grooved spacer. The number of protrusion preventing members can be reduced, and the gap between the annular members can be reduced to 2 by only one cutting point.
The optical fiber accommodated in the double length can be taken out.

According to the optical cable of the fifth aspect, the pop-out preventing member is a net-like body composed of a linear body or a band-like body that is braided around the grooved spacer and is connected to each other at the intersection of the braid. It is possible to open only the optical fiber by cutting the filament or strip near the groove from which the optical fiber is to be taken out.

According to the optical cable of the sixth aspect, the pop-out preventing member is provided in the vicinity of the inversion portion, projects from the side edge of the groove, and has an opening so that the width of the opening is smaller than the diameter of the optical fiber. Since it is a claw-shaped member that covers the optical fiber, it is possible to take out the optical fiber by bending the claw-shaped member in the groove from which the optical fiber is to be taken out.

According to the optical cable of the seventh aspect, the pop-out preventing member is a claw-like member that is provided in the vicinity of the reversing portion and projects from the inner side edge of the groove to the outer side edge to cover the opening. It is possible to take out only the optical fiber by bending or cutting the claw-shaped member of the groove to be taken out.

According to the optical cable of the eighth aspect, since the optical fiber which can be recognized from between the protrusion preventing members has a distinguishable coating, the optical fiber can be easily identified. Then, the protrusion preventing member that prevents the protrusion of the optical fiber to be extracted is deformed by cutting or bending, or the part integrated with the grooved spacer is removed to extract the required optical fiber. You can

According to the ninth aspect of the invention, the cable core can be protected by having the outer jacket on the outer circumference.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is for explaining the first embodiment of the present invention. FIG. 1 (A) is a perspective view with a part of the outer cover removed, and FIG. It is explanatory drawing of the extraction method of an optical fiber. In the figure, 1 is a jacket, 2 is a grooved spacer,
3, 3a are grooves, 4, 4a are optical fibers, 5, 5a, 5b
Is a striatum or a strip.

The overall structure will be described with reference to FIG. The grooved spacer 2 has a plurality of grooves 3 formed around its periphery, the grooves 3 having the inversion direction reversed at a constant length. This groove 3
Is an SZ type slot. An optical fiber (not shown) is accommodated in each groove 3, and a linear body or a strip body 5 is provided thereon.
Are fixed to the grooved spacer 2. Each filament or strip 5 is fixed to the grooved spacer 2 by being integrated with the grooved spacer 2 at a portion where each filament or strip 5 is in contact with the outer periphery of the grooved spacer 2. There is. As a fixing method, a method such as welding, adhesion, or engagement can be adopted. The fixing of each filament or strip 5 does not need to be fixed over all of the portion where each filament or strip 5 contacts the grooved spacer 2, that is, the portion between the grooves, but in part For example, they may be fixed by dot-shaped portions.

In the structure shown in FIG. 1 (A), the same number of filaments or strips 5 as the number of grooves are provided in the grooves 3 in the reversing portion 4.
The opening of the groove 3 is locally sealed including the opening of the above. However, the number of grooves 3 and the number of filaments or strips 5 do not necessarily have to be the same. The jacket 1 is applied from above.

In the state where the jacket 1 is removed, the opening of the groove is partially sealed by each filament or strip 5, so that the optical fiber that tends to jump out from the inverted portion of the groove is suppressed. And each line or strip 5
However, it is a pop-out prevention member.

A method of taking out an optical fiber will be described with reference to FIG. In this figure, only three grooves near the inverted portion of the groove 3 are shown. The groove 3a is a groove from which the optical fiber 4a is taken out, and the optical fiber 4 is accommodated in the other groove 3. When the optical cable is branched at the intermediate portion, first, as shown in FIG. 1A, a part of the jacket 1 of the optical cable is removed over an appropriate length. It returns to FIG. 1 (B) and demonstrates. The part where the linear member or the strip members 5a, 5b that seal the groove 3a from which the optical fiber is to be taken out is cut is cut and, if necessary, bent upward as shown in the figure. To release the seal. Then, the optical fiber 4a can be lifted out of the groove 3a as shown in the drawing. The optical fiber to be taken out can be identified by observing the optical fiber housed in the groove 3 through the gap between the linear body or the strip body 5. In order to facilitate identification, it is preferable that the coating of the optical fiber be colored or patterned.

As the material of the filament or strip described with reference to FIG. 1, tape, ribbon, thread, string, untwisted thread, metal wire, etc. can be used. In particular, a synthetic resin thread such as nylon or a metal fiber thread is used, and after accommodating the optical fiber in the groove 3, the optical fiber is put along a grooved spacer 2 made of a thermoplastic resin in the longitudinal direction of the optical cable, and these are heated. In this state, the filamentous body or the band-shaped body 5 can be fixed to the grooved spacer 2 by a process in which the grooved spacer 2 is fused and integrated. When a metal is used for the linear body or the strip body 5, the metal wire can be integrated with the grooved spacer 2 in a heated state. The metal wire may be energized to heat it.

As a specific example, the grooved spacer 2 is
It is made of polyethylene with a diameter of 10 mm, and the groove 3 has a width of 1.2 mm and a depth of 1.6 mm. As the filament or strip 5, a polyethylene tape having a width of 1 mm and a thickness of 0.2 mm was used. The optical fiber 4 is
A nylon-coated core wire having an outer diameter of 0.9 mm. As the optical fiber, any fiber such as a single-core or multi-core resin-coated optical fiber core wire or a tape-shaped core wire can be used.

FIG. 2 is a perspective view of the optical cable according to the second embodiment of the present invention with a part of the jacket removed. In the figure,
The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The illustration of the optical fiber housed in the groove 3 is omitted. 6 is a striatum or a strip. In this example,
It differs from the first embodiment in that the filament or strip 6 is spirally wound around the grooved spacer 2 in one direction. Similar to the first embodiment, the filament or strip 6 is fixed to and integrated with the grooved spacer 2 at a portion in contact with the outer periphery of the grooved spacer 2.

In the structure shown in FIG. 2, only one filament or strip 6 is used, but the number of filaments or strips 6 need not be limited to one, and a plurality of filaments or strips may be wound to form a unit with the grooved spacer 2. May be turned into.

As the material and fixing method of the filament or strip, the same materials as in the first embodiment can be used. The filament or strip 21 is integrated with the grooved spacer 2 after winding. Therefore, since it does not loosen in the rewinding direction thereafter, it is not always necessary to wind in one direction, and the winding direction may be changed appropriately.

Also in the second embodiment, as in the first embodiment, the optical fiber (not shown) housed in the groove 3 is seen through the gap between the filaments or strips 6 for identification. be able to. Then, in the vicinity of the inverted portion of the groove 3, the filament or strip 6 that prevents the optical fiber to be taken out from protruding is cut at the upper part of the groove 3 to take out the desired optical fiber. The other optical fibers are in the sealed state by the filament or the strip 6, and therefore do not come out of the groove 3.

FIG. 3 is a perspective view of an optical cable according to a third embodiment of the present invention with a part of the jacket removed. In the figure,
The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The illustration of the optical fiber housed in the groove 3 is omitted. Reference numeral 7 is an annular member. In this embodiment, the annular member 7 is provided intermittently in the longitudinal direction of the grooved spacer 2,
This is different from the first or second embodiment. The annular members 7 may be provided at regular intervals or irregular intervals. The annular member 7 is fixed to and integrated with the grooved spacer 2 at a portion in contact with the outer circumference of the grooved spacer 2, as in the first and second embodiments. The annular member 7 serves as a protrusion preventing member that suppresses the optical fiber that is about to protrude from the groove 3. In a preferred embodiment of this embodiment,
The annular member 7 is provided near the inverted portion of the groove 3.
However, it is not always necessary to provide one annular member for each reversal portion, and for example, for one reversal portion,
You may make it provide several annular members.

The annular member 7 is an annular member having a notch in a part thereof, and the notched spacer 2 of the grooved spacer 2 is expanded by expanding the notched spacer 2 after the optical fiber is accommodated in the groove 3. It may be fitted from the side. Also,
The annular member 41 may also be formed by winding a linear or strip-shaped body having a predetermined length around the grooved spacer 2 once or several times.

As the material and fixing method of the annular member 41,
It is possible to use the same material and fixing method as the material for the filament or strip in the first embodiment.

In this embodiment, it is easy to look into the optical fibers housed in the groove 3 and identify the individual optical fibers by the color or pattern of the surface thereof. And
A desired optical fiber can be taken out by cutting the annular member 7 above the groove 3 in which the optical fiber to be taken out is housed in the vicinity of the inverted portion of the groove. In this embodiment, the pop-out preventing member can be reduced, and when one annular member 7 is used for each inversion portion of the groove 3, only one point of the annular member 7 is cut to reduce the gap between the annular members to 2 There is the advantage that the optical fiber housed in the groove between the double lengths can be taken out.

FIG. 4 is a perspective view of an optical cable according to a fourth embodiment of the present invention with a part of the jacket removed. In the figure,
The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The illustration of the optical fiber housed in the groove 3 is omitted. 8 is a reticulate body. In this embodiment, a mesh-like body in which a filament or a strip is spirally wound around the outer periphery of the grooved spacer 2 accommodating the optical fiber in the opposite direction to the one direction and used is used. The filaments or strips are fixed to each other at the intersections of the braid, so that the grooved spacers 2 are covered with a net. Since this mesh-like body suppresses the optical fiber that tries to come out from the inverted portion of the groove 3, it locally seals the opening of the groove 3 and serves as a pop-out preventing member. The number of these filaments or strips may be arbitrary, and the number and pitch of the filaments or strips wound in one direction and the number of the filaments or strips wound in the opposite direction, They may be the same or different.

As the material of the mesh body 8, the same material as in the first embodiment can be used. The intersection of the braid is
They can be fixed to each other by welding or adhesion using an adhesive. Furthermore, it may be fixed to a part of the outer periphery of the grooved spacer 2.

Also in this embodiment, as in the first embodiment, the optical fiber accommodated in the groove 3 can be recognized from the gap of the mesh 8. Then, in the vicinity of the inversion portion of the groove 3, the desired optical fiber can be taken out by cutting the net-like body 8 which prevents the optical fiber to be taken out at the upper part of the groove 3.

FIG. 5 is an explanatory view for explaining the fifth embodiment of the present invention, and is an enlarged view of the vicinity of the inversion part of a part of the groove, as in FIG. 1 (B). In the figure, the same parts as those in FIG. 9,9a
Is a claw-shaped member. In this embodiment, a claw-shaped member is provided in the groove without using a member surrounding a grooved spacer that accommodates an optical fiber, such as a linear member, a strip member, an annular member, or a mesh member. This is different from each embodiment described above. The claw-shaped members 9 and 9a are formed so as to project from the inner side edges of the grooves 3 and 3a toward the outer side edges and cover the openings at the inverted portions of the grooves 3 and 3a. The claw-shaped members 9 and 9a are configured to suppress the optical fiber that tends to jump out from the inverted portion of the groove 3. Therefore,
The claw-shaped members 9 and 9a locally seal the openings of the grooves 3 and 3a and serve as a protrusion preventing member for the optical fibers 4 and 4a. The number of claw-shaped members provided in one reversing portion is not limited to one. It may be two or more places.

Since the optical fiber 4 tries to go out to the inner side edge side of the inverted portion of the groove 3, the claw-shaped members 9 and 9 are formed.
It is more difficult for the optical fiber to pop out when a is projected from the inner side edge of the inverted portion of the groove 3. The optical fiber 4a can be taken out by widening the gap between the claw-shaped member 9a of the groove 3a in which the optical fiber 4a to be taken out is accommodated and the outer side edge of the bending reversal portion.

It is desirable that the claw-shaped members 9 and 9a cover a part of the opening so that the width of the opening of the groove 3 is partially smaller than the diameter of the optical fibers 4 and 4a. However, when the claw-shaped members 9 and 9a are provided on the inner side edge of the reversing portion, the optical fiber is unlikely to pop out, so that such a condition is relaxed.

As a method of manufacturing the grooved spacer 2 having such a structure, first, when the grooved spacer 2 is molded, a protruding structure is provided on the inner side edge of the inverted portion of the groove 3,
After housing the optical fiber 4 in the groove 3, this protruding structure can be heated and molded into a shape along the outer side edge of the grooved spacer 2. Alternatively, after accommodating the optical fiber 4 in the groove 3, the claw-shaped member 9 may be attached as a separate component by welding or adhesion.

As a modified example of the fifth embodiment, a claw-shaped member may be used as a connecting member which locally bridges both side edges of each groove 3 in the vicinity of the inverted portion of the groove 3.
In this modification, the desired optical fiber can be taken out by cutting the claw-shaped member that prevents the optical fiber to be taken out from jumping out. The grooved spacer 2 having such a structure can be manufactured by the same method as the grooved spacer 2 having the claw-shaped member described above. Alternatively, a coupling member as a separate component may be simply pushed into the groove to serve as a pop-out prevention member.

In the above-mentioned embodiment, the outer periphery of the grooved spacer accommodating the optical fiber provided with the protrusion preventing member is covered with the outer cover. It is common to use a synthetic resin coating as the outer cover. Of course, the outer cover may be formed of a plurality of layers, for example, by applying a synthetic resin coating on the press-wound layer, or by applying a plurality of layers of synthetic resin coating. A tensile strength member may be arranged inside the grooved spacer.

Of course, in the present invention, it is not necessary to directly coat the optical cable. If a weatherproof optical fiber is used, it can be installed as it is. In addition, a plurality of optical cables described in the above-described embodiments, which are not covered by the optical cable or which are covered by a press-winding cable, may be twisted together to form a multi-fiber optical cable.
In this case, the strength member may be arranged at an appropriate place such as the central portion.

[0048]

As is apparent from the above description, according to the present invention, when an optical cable is branched at an intermediate portion, it is possible to take out a predetermined optical fiber without causing another optical fiber to jump out. In addition, it is possible to visually recognize the optical fiber housed in the groove with the outer cover removed,
There is an effect that it is easy to identify the optical fiber to be taken out for branching.

[Brief description of drawings]

1A and 1B are views for explaining a first embodiment of the present invention, FIG. 1A is a perspective view with a part of an outer cover removed, and FIG. It is explanatory drawing of a method.

FIG. 2 is a perspective view of an optical cable according to a second embodiment of the present invention with a part of a jacket removed.

FIG. 3 is a perspective view of an optical cable according to a third embodiment of the present invention with a part of an outer cover removed.

FIG. 4 is a perspective view of an optical cable according to a fourth embodiment of the present invention with a part of an outer cover removed.

FIG. 5 is an explanatory diagram illustrating a fifth embodiment of the present invention.

[Explanation of symbols]

1 ... Jacket, 2 ... Spacer with groove, 3, 3a ... Groove, 4, 4
a ... Optical fiber, 5, 5a, 5b ... Striation or strip, 6 ... Striation or strip, 7 ... Ring member, 8 ... Net, 9, 9a ... Claw member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Tanaka 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Osamu Kawada 1-6, Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Kazuo Hokari 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (9)

[Claims] 1. In an optical cable having a grooved spacer having a plurality of grooves on the outer periphery, the groove direction of which is reversed at regular intervals, and an optical fiber housed in the groove, the opening of the groove is locally sealed. An optical cable having a pop-out prevention member. 2. The protrusion preventing member is a linear member or a band-shaped member provided along the longitudinal direction of the optical cable around the grooved spacer, and the groove is provided at a portion in contact with the outer periphery of the grooved spacer. The optical cable according to claim 1, wherein the optical cable is integrated with an attached spacer. 3. The pop-out prevention member is a linear member or tape wound around the grooved spacer, and is integrated with the grooved spacer at a portion in contact with the outer periphery of the grooved spacer. Claim 1 characterized by the above-mentioned.
Optical cable described in. 4. The pop-out prevention member is an annular member provided in the vicinity of the reversal portion, and is integrated with the grooved spacer at a portion in contact with the outer periphery of the grooved spacer. The optical cable described in 1. 5. The pop-out preventing member is a net-like body composed of filaments or strips that are meshed around the grooved spacers and are connected to each other at the intersections of the meshes. The optical cable described in 1. 6. The protrusion preventing member is provided in the vicinity of the inversion portion, protrudes from the side edge of the groove, and covers the opening so that the width of the opening is smaller than the diameter of the optical fiber. It is a member, The optical cable of Claim 1 characterized by the above-mentioned. 7. The pop-out prevention member is a claw-shaped member that is provided in the vicinity of the reversal portion and projects from the inner side edge of the groove to the outer side edge to cover the opening. Optical cable. 8. The optical cable according to claim 1, wherein the optical fiber housed in the groove has an identifiable coating. 9. The optical cable according to claim 1, further comprising an outer jacket on the outer circumference.