JP2978104B2 - Self-supporting pipe composite 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 self-supporting pipe composite cable in which a pipe for passing an optical fiber, a core of a power or communication cable, and a support wire for supporting the pipe and the core are commonly coated with a resin or the like. For example, leakage to secure wireless communication with trains and automobiles in places where terrestrial waves are difficult to reach, mainly in subway tunnels, automobile tunnels, etc., or near railway tracks, etc. Although it is used as a coaxial cable or the like, it can also be used as a composite cable of a power cable and an optical fiber laid in the city.

[0002]

2. Description of the Related Art There has been a self-supporting pipe composite cable in which a support wire (tensile member) such as a pipe, an electric cable, and a messenger wire for passing an optical fiber is combined. Basically, a pipe is wound with a binding wire such as a lashing wire along with a support wire along a composite electric wire cable integrated with an electric wire cable, or is covered with an insulating resin in common. Was. However, in such a self-supporting pipe composite cable in which the pipe is integrated with the electric cable, the pipe is separated and pulled out, or only the electric cable is separated and pulled out from the common coating layer and branched and connected. Also, when connecting to other cables, the entire self-supporting pipe composite cable must be housed in a connection box for protection, and there is a problem in workability.

In order to solve the above problem, a self-supporting pipe composite cable shown in FIG. 2 has been developed and put into practical use. In this, a pipe A for passing an optical fiber, a core B of an electric cable, and a support wire C are arranged at appropriate intervals, and these are commonly coated with a resin or the like. In this self-supporting pipe composite cable, there are various patterns in the arrangement of the pipe A, the cable core B, and the support line C. For example, as shown in FIG. 2, the pipe A, the support line C, and the cable core B are arranged in order from top to bottom. Some are arranged in order, some are arranged in the order of the support line C, the pipe A, and the cable core B, and some are arranged in the order of the support line C, the cable core B, and the pipe A. In some cases, the pipe A, the cable core B, and the support wire C are not arranged linearly. In any case, in these self-supporting pipe composite cables, pipes A,
The pipe A and the cable core B can be easily separated by cutting the thin space forming portion D between the cable core B and the support wire C with a blade or the like, and furthermore, any one of them can be used. Even when the member is separated, the coating of the other member is not peeled off, so that it is not necessary to store the separated portion in the connection box and protect it.

[0004]

However, the self-supporting pipe composite cable shown in FIG. 2 has the following problems. . Generally, since the pipe A is often made of plastic, the melting point of the pipe A is close to the melting point of the outer shell. Therefore, when the jacket is peeled off from the pipe A in the connection work at the terminal, the jacket is closely adhered (fused) to the pipe A, and the separation of the jacket is very troublesome. . In order to solve the above-mentioned difficulties, it is only necessary to prevent the jacket from being closely attached (fused) to the pipe A. However, in this case, the supply tension (supply tension) of the pipe A is required at the time of manufacturing the self-supporting pipe composite cable. ) Needs to be highly controlled so that the pipe A does not fall out of the jacket, which makes the production difficult. Also, due to the difference in the thermal expansion coefficient between the pipe A and the support wire C, the pipe A may expand and contract after the self-supporting pipe composite cable is laid. The expansion and contraction of the pipe A may adversely affect the optical fiber taken out of the pipe A in the optical fiber connection box.

SUMMARY OF THE INVENTION An object of the present invention is to make it easy to peel off the jacket of a pipe through which an optical fiber passes, especially a plastic pipe, to manufacture a cable easily, and to use an optical fiber passing through the pipe. An object of the present invention is to provide a self-supporting pipe composite cable that is less likely to break.

[0006]

According to the present invention, there is provided a self-supporting pipe composite cable according to the first aspect of the present invention, as shown in FIG. Is a self-supporting pipe composite cable that is commonly covered by a jacket 4 at appropriate intervals, wherein the pipe 1 and a jacket 4 covered around the pipe 1 are partially bonded.

A self-supporting pipe composite cable according to a second aspect of the present invention is formed by partially bonding a pipe 1 and a jacket 4 surrounding the pipe 1 in a circumferential direction of the pipe 1. is there.

According to a third aspect of the present invention, there is provided a self-supporting pipe composite cable in which a pipe and a jacket surrounding the pipe are partially bonded in a longitudinal direction of the pipe. is there.

[0009]

According to the self-supporting pipe composite cable of the present invention,
In a self-supporting pipe composite cable in which a pipe 1, a support wire 2, and a cable core 3 for passing an optical fiber therein are commonly covered by a jacket 4 at appropriate intervals,
Since the pipe 1 and the jacket 4 covering the periphery thereof are partially adhered, the light in the optical fiber connection box due to the detachment of the pipe 1 during the production of the cable and the expansion and contraction of the pipe 1 after the cable is laid. Both adverse effects on the fiber are prevented,
Further, the jacket 4 of the pipe 1 is easy to peel off. In the pipe 1, an optical fiber may be passed before the cable is laid, or may be passed after the cable is laid. As a method of passing an optical fiber through a pipe before laying a cable, a method of manufacturing a pipe with an optical fiber by supplying an optical fiber inside while extruding the pipe is to make a cut in the pipe when manufacturing the pipe. There is a method of manufacturing an optical fiber-containing pipe by inserting an optical fiber from the cut. Further, as a method of passing an optical fiber through a pipe after laying a cable, there is a method of passing an optical fiber through a pipe by air pressure.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the self-supporting pipe composite cable of the present invention will be described in detail with reference to FIG.
1 is a plastic pipe, 2 is a support wire, and 3 is a cable core (in this case, a leaky coaxial (L
CX) cores of cables, which are sequentially arranged from top to bottom, and which are made of a plastic sheath (sheath) 4.
Are commonly coated. Here, the pipe 1, the support wire 2, and the cable core 3 are arranged such that their centers are located on the same straight line, and between the pipe 1 and the support wire 2, and between the support wire 2 and the cable core 3. Each of the thin gap forming portions 15
Are formed.

The plastic pipe 1 is disposed directly above the cable core 3 (more precisely, directly above the support wire 2). In this embodiment, the pipe 1 compresses the optical fiber after laying the cable, such as compressed air. It is hollow so that it is pumped together with it. As the plastic, a polyethylene pipe or the like is used. This pipe 1 is shown in FIG.
As shown in the figure, a part of its circumference is bonded (fused) to the jacket 4.
It is bonded (fused) to the jacket 4 intermittently in the longitudinal direction.

The support wire 2 is also called a suspension wire or a messenger wire, and for example, a stranded wire of galvanized steel wire is used.

The cable core 3 includes a center conductor 10, an inner insulator 11, which is a spiral made of a square polyethylene string, an outer insulator 12 such as a polyethylene pipe, a metal, and the like. Made of an external conductor 13 made of aluminum. The outer conductor 13 has a large number of slit-like slots (grooves) formed in its peripheral wall in the circumferential direction, for example, diagonally and at uniform intervals. Signals transmitted from the slots to the central conductor 10 are leaked to the outside. It has become so.

In manufacturing the self-supporting pipe composite cable described above, the following method may be used, for example. 1. Most of the outer circumferential surface of the pipe 1 in the circumferential direction is
In the longitudinal direction, a release agent of silicone resin is applied intermittently. As a method of applying the release agent in this case, a method of applying the release agent to the entire peripheral surface of the pipe 1 and then partially wiping the release agent so that the release agent remains at a desired portion, There is a method in which a release agent is applied only to a desired portion from the beginning. In this case, the release agent may be applied to the pipe 1 immediately before the crosshead of the extruder. 2. The pipe 1 is coated with a support wire 2 and a cable core 3 together with an extruder in the form shown in FIG.
To form 3. Since this common coating is usually performed by heating the resin, the portion of the pipe 1 where the release agent is not applied temporarily comes into contact with the high-temperature resin forming the jacket 4. Since the material of the pipe 1 has a melting point close to that of the resin, the portion where the release agent is not applied is melted and fused with the jacket 4. In addition, the pipe 1 in the portion where the release agent is applied does not melt due to the heat insulating effect of the release agent, and thus is not fused to the jacket 4. Thus, a self-supporting pipe composite cable in which the pipe 1 and the jacket 4 are partially fused is finally completed.

The above is one embodiment of the self-supporting pipe composite cable of the present invention. In the self-supporting pipe composite cable of the present invention, the bonding portion between the pipe 1 and the jacket 4 is shown in FIG.
It is not limited to the location. In other words, the size and the position of the bonding portion in the circumferential direction are not limited to those shown in FIG. 1A, and the size of the bonding portion in the longitudinal direction is as shown in FIG.
It is not limited to the one shown in FIG. The bonding portion in the present invention may satisfy the condition described later, and may be provided continuously in the longitudinal direction, for example. The conditions required in the present invention are as follows. 1. Pipe 1 during manufacture of self-supporting pipe composite cable
The pipe 1 can be prevented from coming off without a high degree of control of the supply tension (supply tension) of
And that the optical fiber passed through the pipe 1 has such strength that it does not break due to the difference in the thermal expansion coefficient of the pipe 1 and the thermal expansion coefficient. 2. The size and position of the bonding portion are appropriately selected so that the bonding portion is suppressed so that the outer cover 4 of the pipe 1 is easily peeled off, that is, the two contradictory conditions are satisfied well.

In the present invention, the pipe 1 and the jacket 4 may be partially adhered by the following method. 1. A release agent other than silicone resin is used. For example, there is no affinity with the pipe 1 and the jacket 4 and there is no influence (for example, it does not chemically react with the pipe 1 and the jacket 4), and even if a resin having a high heat insulating effect is used, the same effect as the silicone resin can be obtained. Obtainable. 2. Without using a release agent, a plastic tape or a plastic thread (for example, Kevlar or the like) made of polyester or the like having a higher melting point than the material of the jacket 4 is vertically attached to the outer periphery of the pipe 1.
Alternatively, these can be wound sideways with a gap
And the high-temperature resin forming the jacket 4 are partially brought into contact with each other so that the pipe 1 and the jacket 4 are bonded only at the contacted portions. 3. By devising the cross-sectional structure of the jacket 4 by partially increasing the thickness of the jacket 4, the cooling time of the resin forming the jacket 4 is varied, and the pipe 1 and the jacket 4 are bonded at the portion where cooling is delayed. To be done.

In the above embodiment, an example is shown in which a plastic pipe of a type in which an optical fiber is pressure-fed after a cable is laid is used as a pipe. However, as described above, the feature of the present invention is that the pipe and the outer skin are bonded to each other. As such, it is not limited to only this type of pipe.

[0018]

The self-supporting pipe composite cable of the present invention has the following effects because the pipe and the jacket are partially adhered. 1. The work of separating the jacket and the pipe at the terminal is easy. 2. Pipes do not come off without sophisticated control of pipe supply tension during cable manufacturing. 3. Since the pipe is difficult to expand and contract, the optical fiber passed through the pipe is hard to break.

[Brief description of the drawings]

FIG. 1 is an embodiment of a self-supporting pipe composite cable according to the present invention, wherein (a) is a cross-sectional view of the cable, and (b) is a perspective view of the cable.

FIG. 2 is a perspective view showing an example of a conventional self-supporting pipe composite cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 Support wire 3 Cable core 4 Jacket

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 6/44 H01B 7/18 H01B 11/22

Claims (3)

(57) [Claims] 1. A self-supporting pipe composite cable in which a pipe (1), a support wire (2), and a cable core (3) are commonly covered with a jacket (4) at appropriate intervals.
A self-supporting pipe composite cable, characterized in that said pipe (1) and a jacket (4) covered therearound are partially adhered. 2. The self-powering device according to claim 1, wherein the pipe (1) and a jacket (4) covering the periphery thereof are partially bonded in a circumferential direction of the pipe (1). Support type pipe composite cable. 3. The pipe (1) and a jacket (4) coated around the pipe (1) are partially adhered in the longitudinal direction of the pipe (1). 2
A self-supporting composite pipe composite cable as described.