JPH07294786A - Tube type optical cable and its use method - Google Patents

Abstract

PURPOSE:To provide a novel tube type optical cable with which post-branching is easy. CONSTITUTION:Many pieces of tubes 3 are doubled and twisted at a long pitch around a central cord 4 in a main body part 1 of this tube type optical cable. A sheath 6 is applied thereon. A tear cord 5 is disposed on the inner side of this sheath 6. The central cord 4 is interposed in order to be a center at the time of assembling the tubes 3. A tensile body 2 is formed by bundling plural pieces of tensile wires 7 and applying a coating 8 thereon. This coating 8 is integrated to the sheath 6 of the main body part 1. The sheath is opened by the tear cord 5, by which the sheath of the required length part is removed and the tubes to be post-branched are drawn out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube type optical cable used for laying and carrying an optical fiber in an air stream and a method of using the tube type optical cable. It is related to a technique useful for doing.

[0002]

2. Description of the Related Art As an example of a conventional tube type optical cable and its usage, "Sumitomo Electric" No. 140, Nos. 50-5
Although there are those described on page 5, the number of tubes that can be stored in one of the vertical tube type optical cables described here is up to 6 when the tensile strength body is inserted in the center. Where there is a possibility of cutting the tubes and wiring them in the horizontal system (floor system), cabinets are provided in advance, and the tube type optical cable is cut in each cabinet and the extra length is stored. There is. For this reason, when horizontal wiring is required, the tubes can be connected in these cabinets to allow post branching of the tube type optical cable.

However, with the recent development of communication networks, the need for large-capacity communication such as transmission of image information is increasing, and it is becoming a situation that optical fiber networks are introduced near each terminal device. The number of optical fiber cores required for wiring is also very large. This requires increasing demand for the number of tubes in the tube type optical cable.

In order to increase the number of tubes, the conventional structure of stacking tubes in layers is used, for example, 1
When a multi-tube cable such as a 9-tube tube or a 61-tube tube was manufactured, it was in a form of multilayer lamination.

On the other hand, from the viewpoint of reducing the cost of optical wiring, it is effective to lay a tube type optical cable once in a series of lengths and not install a cabinet at a point where tube branching is not necessary at the initial stage. Can be said.

However, in the conventional tube type optical cable and the method of using the same, a tube type optical cable in which a relatively small number of tubes are assembled is used, a cabinet is provided in advance at the branch point of the tube, and the tube type optical cable is installed in the cabinet. The method of fixing the central strength member and fixing the tube with the connector or fixing the outer circumference of the tube type optical cable and fixing the tube with the connector was adopted. However, in the case of branching in a cabinet as has been conventionally done, there arises a problem that it is difficult to take out the tube of the inner layer, and the post branching itself is difficult. Moreover, there is a problem that the cabinet itself becomes extremely large.

As a cable structure for facilitating post branching,
In a normal optical cable, a structure using an SZ slot is known, but it is possible to apply this to twist the tube of the tube type optical cable into SZ. In this case, it is useful to shorten the twist pitch because a larger tube extra length can be taken, but conversely, there is a problem that the tube is bent at a short cycle and the optical cable cannot be easily transmitted by an air flow.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a new tube type optical cable which can be easily branched and a method of using the same, by radically reviewing the conventional method itself. That is the purpose.

[0009]

According to a first aspect of the present invention, a plurality of tubes for gathering and carrying an optical fiber on an air stream are assembled and a tear string is provided on the outer side of the tube. The tube according to claim 1 is characterized in that it has a main body portion provided with a sheath, and a strength member provided outside the main body portion. In the optical fiber cable, a large number of plastic tubes are laminated and assembled from an inner layer to an outer layer. In the invention of claim 3, in the tube type optical cable of claim 1, It is characterized in that a unit made up of several plastic tubes is laminated and assembled from the inner layer to the outer layer.

According to a fourth aspect of the present invention, there is provided a method of using the tube type optical cable according to the first to third aspects.
After laying the tube type optical cable according to any one of 1 above in a straight line, the sheath is removed over a desired length,
The outer tube or the upper tube is stretched by applying a light tension to open the gap, and the required tube or unit is taken out to the outside for branching.

According to a fifth aspect of the invention, in the method of using the tube type optical cable according to the fourth aspect,
A portion of the tube type optical cable obtained by branching the tube or the unit after the sheath except the sheath is not housed in the cabinet. In the invention of claim 6, the tube type of claim 4 or 5 is used. In the method of using the optical cable, a protection means for holding the tube or the unit from the outer periphery is applied to a portion of the tube type optical cable obtained by branching the unit except the sheath so that the tube does not spread outside. In the invention according to claim 7, in the method of using the tube type optical cable according to any one of claims 4 to 6, the tube branched after is placed in a cabinet arranged so that the tube type optical cable does not penetrate therethrough. It is characterized in that the terminal is processed by guiding it so as not to bend it with a small diameter. .

[0012]

The tube type optical cable of the present invention has a tear cord on the outermost side together with many tubes, and a tensile strength body on the outer side. Therefore, at the time of laying, a tensile strength member is used and a tensile force is applied to the strength member or the strength member is fixed to fix the tube type optical cable to a desired fixing member. Further, by separating the strength member from the main body of the tube type optical cable, the relatively flexible tube type optical cable main body which does not include the strength member can be handled alone.

A tube type optical cable laid in a building or the like has a small tension applied to the cable after laying, such that the cable is supported at many points in the longitudinal direction by saddles or bind wires in the laid state. , It is usual that the tensile strength body is rarely used. Therefore, when laying the main body without the tensile strength member, most of the material of the main body, that is, the sheath as well as the tube is made of plastic, so if the length is about several percent. It can be easily extended and installed, and there is a degree of freedom in installation. At this time, it is also useful to provide a notch for tearing between the main body and the strength member.

On the other hand, by using a tear cord for the sheath, the sheath of the tube type optical cable having a length of about 2 m can be easily removed. By removing the sheath, it is possible to use the elasticity of the inner tube to pull out the inner one of the multilayered tube, which can be cut to connect with the horizontal tube type optical cable or for extension. The tubes can be joined to prepare for the subsequent passage of the optical fiber unit.

That is, in the tube type optical cable of the present invention, the tensile strength member for installation is separated, and further, the sheath of the tube type optical cable body is removed over a long length,
By utilizing the fact that the plastic tube can easily be stretched by utilizing its elasticity if it is about several percent, the required tube can be branched after the required tube is opened or pulled out. By this method,
In addition to allowing post branching at any position of the tube type optical cable that stores much more tubes than before, in addition to the possibility of branching all the tube type optical cables,
It is possible to simply install a series of tube-type optical cables without requiring an extra length for branching, a complicated work such as installing a cabinet in advance, or a cost. The length at which the sheath of the main body of the tube-type optical cable is torn at the time of post-branching can be set sufficiently longer than the height inside the cabinet that processes the taken out tube. The size of the cabinet can be reduced because it is not stored in.

The tube in the tube type optical cable can be satisfactorily worked by unidirectional twisting with a long period,
It is possible to use the technology of the past in manufacturing as it is, and it is possible to avoid the adverse effect on the communication performance due to the inversion in the tube having the SZ twist of a short cycle.

[0017]

FIG. 1 is a sectional view of an embodiment of the tube type optical cable of the present invention. In the figure, 1 is a main body part, 2 is a tensile strength body, 3 is a tube, 4 is a center string, 5 is a tear string, 6 is a sheath, 7 is a tensile strength wire, and 8 is a coating. In the main body 1, a large number of tubes 3 are twisted around a central string 4 at a long pitch, and a sheath 6 is applied thereon. The tear string 5 was arranged inside the sheath 6. The center string 4 is interposed to serve as the center when the tubes 3 are assembled. The tensile strength body 2 is formed by bundling a plurality of tensile strength wires 7 with a coating 8, and the coating 8 is integrated with the sheath 6 of the main body 1.

In one specific example of this embodiment, a polyethylene tube having an inner diameter of 4.5 mm and an outer diameter of 6 mm was used as the tube 3. A number for identification was printed on each tube. A polyethylene wire was used for the tear string 5. In the tensile strength member 2, a steel stranded wire was coated with polyethylene. This strength member has a tension sufficient to catch a 150 m tube type optical cable.

FIG. 2 is a sectional view of another embodiment of the tube type optical cable of the present invention. In the figure, the same parts as those in FIG. 9 is a unit, 1
0 is a holding roll. In this example, four tubes 3 were gathered around the center string 4 to form a unit. The tube 3 may be twisted around the center string 4 or may be vertically attached, and the press winding 10 is applied.
In this example, seven units were twisted together, but they do not necessarily have to be twisted. Similar to the above-described embodiment, the tear string 5 is disposed, the sheath 6 is applied to form the main body portion 1, and the strength member 2 is integrated on the outer side thereof.

FIG. 3 is an explanatory view of the laying condition of the tube type optical cable of the present invention. In the figure, 1 is a main body, 2 is a strength member, 11 is a cable rack, and 12 is a saddle. As the tube type optical cable, the one in which the 19 tubes of the embodiment described in FIG. 1 were integrated was used. The tube type optical cable linearly penetrates a predetermined floor, and the main body 1 is fixed to the cable rack 11 by the saddle 12 together with the strength member 2.

FIG. 4 is an explanatory view of an embodiment of a method of using the tube type optical cable of the present invention for performing post branching. In the figure, the same parts as those in FIG. 3a is a branch tube, 13 is a tear portion, 14 and 15 are binding members, 15a is a guide, 16 is a protective member, 17 is a fixing tape, 18 is a cabinet, 19
Is a floor cable, and 20 is a tube connector.
First, as shown in FIG. 4 (A), the sheath 6 was torn using the tear string 5 to form the tear portion 13. The length of the tear portion 13 is 1.5 m in this embodiment.

Next, using the tearing portion, as shown in FIG.
As shown in (B), the sheath is cut out so that the tube can be taken out, and a light tension is applied to the tube 3 in the section where the sheath is removed over this long length to slightly extend the tube 3 and The tube was spread around. By this work, the tube inside could be easily taken out. At this time, the strain generated in the tube was very easy because the tube of several cm could be pulled out of the cable with an extension of 1 mm or less per 1.5 m.

After taking out the branch tube 3a for post-branching and cutting it, as shown in FIG. 4 (C), the required portions are bound by the binding members 14 and 15 that bind the entire tube. The binding members 14 and 15 can be made of an elastic member, for example, an elastic resin or metal. The bundling member 15 provided in the portion where the branch tube 3a is pulled out
The guide 15a is formed, and the branch tube 3a is pulled out along the guide 15a. By using the guide 15a, the drawn-out portion of the branch tube 3a can be restricted to an appropriate bend. As a result, when connecting one or more tubes and laying an optical fiber in them, there is little bending of the tubes, and it is possible to send the optical fibers with less frictional resistance between the tubes and the optical fibers caused by the bending. Is. FIG. 4D shows the guide 15a.
Is an example of a binding member provided with, and the radius of curvature of the bend of the guide 15a is, for example, 15 cm. The radius of curvature is selected so as not to affect the pumping characteristics.

After the branch tube 3a was pulled out, as a post-treatment for the section where the sheath was removed and the tube was exposed, as shown in FIG. 4 (E), the protective member 15 was put on the sheath removal portion. In the embodiment, as the protection member 15, a tube made of flame-retardant rubber having a notch is used, and the tube is housed in this tube and tied to the cable rack. You may make it fix the protection member 15 using the fixing tape 17.

The post-treatment of this sheath removal portion does not have to be performed in a machine room in a building where the tube is exposed and is not easily deteriorated by sunlight or the like, but the influence of construction of other cables is expected. The protection member 15
It is better to protect by. It can be protected by using a metal pipe, and can take a reinforcing form as required.

The branch tube 3a taken out to the side surface of the tube type optical cable along the guide 15a is introduced into the cabinet 18 for connection with another tube or for taking out the optical cable from the tube. Therefore, the processing in the cabinet 18 is only to store the tube of the required length and the optical cable, and to connect other tubes in the tube type optical cable that does not branch at that point and do not retract, so that the cabinet is It can be very small.

FIG. 5 is an explanatory view of a laying condition in which the rear branch is performed according to FIG. In the figure, the same parts as those in FIGS. 3 and 4 are designated by the same reference numerals and the description thereof will be omitted. In this example,
Since the branch tube 3a is connected to one tube of the floor system cable 19 by the tube connector 20, the cabinet 18 only processes two tubes, and the volume of the cabinet 18 is 1/4 of the conventional volume.
Became.

[0028]

As is apparent from the above description, according to the present invention, it is possible to easily branch the tube-type optical cable afterward, and therefore, the tube-type optical cable can be used in an application where the branching location of the tube-type optical cable is uncertain. It will be useful. Also, by using this structure, it is possible to wire a tube-type optical cable that allows easy branching of the tubes without arranging a special tube that reverses the bending direction of the tubes that deteriorates pumping characteristics such as SZ twisting. is there.

Further, the tube type optical cable before the post branching only penetrates the rack for cable laying in a straight line, has a low space occupancy rate, can effectively use the cable rack, and when laying other cables. It is useful because it does not get in the way.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a tube type optical cable of the present invention.

FIG. 2 is a sectional view of another embodiment of the tube type optical cable of the present invention.

FIG. 3 is an explanatory view of a laying condition of the tube type optical cable of the present invention.

FIG. 4 is an explanatory diagram of an example of a method of using the tube type optical cable of the present invention, in which post branching is performed.

FIG. 5 is an explanatory view of a laying condition in which rear branching is performed according to FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body part, 2 ... Tensile body, 3 ... Tube, 3a ... Branch tube, 4 ... Central string, 5 ... Tear string, 6 ... Sheath,
7 ... Tensile wire, 8 ... Coating, 9 ... Unit, 10 ... Press winding, 11 ... Cable rack, 12 ... Saddle, 13 ... Tear part, 14,15 ... Bundling member, 15a ... Guide, 1
6 ... Protective member, 17 ... Fixing tape, 18 ... Cabinet, 19 ... Floor cable, 20 ... Tube connector.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinobu Matsuo 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works

Claims (7)

[Claims] 1. A main body provided with a sheath provided with a tear string on the outer side of a large number of tubes for placing an optical fiber on an air stream and for laying it, and provided outside the main body. A tube type optical cable having a tensile strength member. 2. A plurality of plastic tubes are laminated and assembled from an inner layer to an outer layer.
The tube type optical cable described in. 3. The tube type optical cable according to claim 1, wherein a unit made up of several plastic tubes is laminated and assembled from an inner layer to an outer layer. 4. After laying the tube type optical cable according to any one of claims 1 to 3 in a straight line, the sheath is removed over a desired length, and the outer or upper layer tube is stretched by applying a light tension. A method of using a tube-type optical cable, characterized in that a required tube or unit is taken out to the outside for branching after opening a gap. 5. The method of using a tube type optical cable according to claim 4, wherein a portion of the tube type optical cable obtained by branching the tube or the unit after the sheath except the sheath is not housed in the cabinet. 6. A tube-type optical cable obtained by branching a unit of a tube or a unit is provided with a protection means for holding the tube from the outer circumference so that the tube does not spread outside, except for the sheath, of the tube-type optical cable. How to use tube type optical cable. 7. The end of the tube is treated by guiding the rear-branched tube so as not to give a small-diameter bend to a cabinet in which the tube-type optical cable is arranged so as not to penetrate therethrough. 6. The method of using the tube type optical cable according to any one of 6 above.