JP4589889B2 - Communication cable and laying method of communication cable - Google Patents

Description

  The present invention relates to a communication cable including a leaky coaxial cable and a method for laying the communication cable, which can be easily laid straight.

Leaky coaxial cables are laid along roads and walls and used for mobile communications. In particular, it is characterized in that efficient communication without unnecessary loss can be achieved by directing a slot for radiating radio waves in a certain direction through which the mobile body passes (Patent Document 1).
JP 2002-314328 A

Here, the conventional technique has the following problems to be solved.
When the leaky coaxial cable is transported to the installation site, it is wound around a drum and loaded on a truck. However, if the cable is pulled out from the drum and installed in the field, the cable has wrinkles and may swell as a whole. In this case, it is required to fix the cable with a support bracket while applying a strong tension to the cable to ensure linearity. Accordingly, there is a problem that workability such as positioning of the support metal is poor. Further, if the curl remains, the direction of the slot cannot be oriented accurately in a certain direction, so that the electric field emitted in the vicinity of the leaky coaxial cable may be disturbed.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication cable that is drawn out from a drum while maintaining linearity, and a method for laying the communication cable.

The following descriptions of <Configuration 1> to <Configuration 8> and [Embodiment 1] to [Embodiment 7] show specific means for solving the above-described problems. Of these, patents are requested for inventions relating to [Claim 1] and [Claim 2] below.
[Invention of Claim 1] A highly rigid support and a leaky coaxial cable are integrally covered with a sheath,
Selecting the material or cross-sectional shape of the high-rigidity support so that the rigidity of the high-rigidity support is greater than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support; and The high-rigidity support body is a plate-shaped body having a circular arc cross section.
Invention of Claim 2 A high-rigidity support body and a leaky coaxial cable are integrally covered with a sheath, and the rigidity of the high-rigidity support body and the leaky coaxial cable excluding the high-rigidity support body and the A communication cable in which the material or cross-sectional shape of the high-rigidity support is selected so as to be larger than the rigidity of the sheath composite,
From the state wound on the drum, release the stress applied to the high-rigidity support, direct the slot of the leaky coaxial cable in a certain direction,
In a substantially straight laying portion, the high-rigidity support is gripped and fixed using a support fitting through the sheath without applying tension,
In the direction changing portion, a part of the high-rigidity support and the sheath is cut, and the leaky coaxial cable of the portion is bent and supported and fixed to a radius larger than an allowable bending radius. Method.
<Configuration 1>
A high-rigidity support and a leaky coaxial cable are integrally covered with a sheath, and the rigidity of the high-rigidity support is higher than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support. The communication cable is characterized in that the material or cross-sectional shape of the high-rigidity support is selected so as to be larger.

  When the high-rigidity support is larger than the rigidity of the leaky coaxial cable / sheath complex excluding this, the linearity of the entire communication cable can be secured by the action of the high-rigidity support. Therefore, meandering during laying work can be suppressed. The electrical characteristics of the leaky coaxial cable portion are stable and uniform along the longitudinal direction.

<Configuration 2>
The communication cable according to Configuration 1, wherein the high-rigidity support is a rod-shaped body having a circular cross section.

  About the thing of a cable structure with a support wire, a straight line can be laid easily.

<Configuration 3>
The communication cable according to Configuration 2, wherein the bar having a circular cross section is made of an electrical insulator.

  Since the cross-sectional shape of the high-rigidity support becomes relatively thick, the electric conductor may adversely affect the radiation electric field of the leaky coaxial cable. If the high-rigidity support is made of an electrical insulator, the influence on the characteristics of the leaky coaxial cable can be reduced.

<Configuration 4>
The communication cable according to Configuration 1, wherein the high-rigidity support is a plate-like body having an arcuate cross section.

  If a plate-like body having an arc shape in cross section is used, the entire cross section of the communication cable can be rounded, and it is not necessary to have a rounded cross section like a cable with a support wire. Therefore, winding around the drum and handling become easy.

<Configuration 5>
The communication cable according to any one of Structures 1 to 4, wherein a plurality of high-rigidity supports and a leaky coaxial cable are integrally covered with a sheath.

  By covering a plurality of high-rigidity supports together, high linearity can be secured with a thin high-rigidity support.

<Configuration 6>
A high-rigidity support and a leaky coaxial cable are integrally covered with a sheath, and the rigidity of the high-rigidity support is higher than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support. The communication cable with the material or cross-sectional shape of the high-rigidity support selected so that the stress applied to the high-rigidity support is released from the state of being wound around the drum, and the leakage is applied. A method for laying a communication cable, characterized in that a slot of a coaxial cable is laid straightly in a certain direction.

  The communication cable is laid in a straight line by taking advantage of the characteristic of the highly rigid support that is straight when the stress is released. Thus, predetermined characteristics can be obtained by directing the slot of the leaky coaxial cable in a certain direction.

<Configuration 7>
A high-rigidity support and a leaky coaxial cable are integrally covered with a sheath, and the rigidity of the high-rigidity support is higher than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support. The communication cable with the material or cross-sectional shape of the high-rigidity support selected so that the stress applied to the high-rigidity support is released from the state of being wound around the drum, and the leakage is applied. The coaxial cable slot is oriented in a certain direction, and in the substantially straight laying portion, the high-rigidity support is gripped and fixed through the sheath in a state where no tension is applied, using a support fitting, and in the direction changing portion, the high height A method for laying a communication cable, comprising: cutting a part of a rigid support and a sheath, and bending and fixing the leaky coaxial cable of the part to a radius larger than an allowable bending radius.

  By partially cutting the high-rigidity support, the communication cable can be laid while changing the direction at a corner having a relatively small radius.

<Configuration 8>
In the communication cable laying method according to Configuration 6 or 7, the communication cable is wound around a drum with a bending radius that does not exceed the elastic limit of the high-rigidity support and is transported to a laying site. How to lay communication cables.

  If the drum is wound around the drum with a bending radius that does not exceed the elastic limit of the high-rigidity support body, the communication cable is pulled out from the drum while maintaining linearity without any curl.

  Hereinafter, embodiments of the present invention will be described in detail for each example.

FIG. 1 is a cross-sectional view of a communication cable according to the first embodiment.
In the figure, the communication cable 1 is cut perpendicularly to the cable axis. In this communication cable, a high-rigidity support 10 and a leaky coaxial cable 11 are integrally covered with a sheath 12. In the leaky coaxial cable 11, an outer conductor 15 having a slot is disposed around a central conductor 13 via an insulator 14. For example, the center conductor 13 is made of an annealed copper wire having a diameter of 3.8 mm. The insulator 14 is made of highly foamed polyethylene having an outer diameter of 10 mm, the outer conductor 15 is made of an aluminum / polyethylene laminate tape having a slot, and the sheath is made of polyethylene or polyvinyl chloride having an outer diameter of 13 mm.

FIG. 2 is a side view of the high-rigidity support 10.
In this figure, the high-rigidity support 10 before the sheath 12 is covered is viewed from the direction of the arrow A shown in FIG. In this embodiment, the high-rigidity support 10 is made of FRP (fiber reinforced plastic). The shape of the high-rigidity support 10 is a rod having a circular cross section. The high-rigidity support 10 is selected such that the material and the cross-sectional shape can be kept in a straight line state without applying an external force by being wound around a drum or the like with a bending radius that does not exceed the elastic limit. Therefore, the material may be metal or plastic. The cross-sectional shape may be a circle or a polygon. Further, instead of a single wire, a plurality of wires twisted together may be used. Furthermore, it is preferable to be made of an electrical insulator so as not to disturb the electric field of the radio wave radiated from the leaky coaxial cable 11. In particular, when the high-rigidity support 10 has a relatively large diameter, when an electric current flows through the high-rigidity support 10, an electric field that harms the surroundings is formed. It is preferable to prevent this. When FRP is used, the entire cable can be reduced in weight, and can be cut and removed more easily than galvanized steel wire, thus simplifying the construction.

FIG. 3 is a side view of the leaky coaxial cable 11.
In this figure, the leaky coaxial cable 11 before covering the sheath 12 is viewed from the direction of the arrow B shown in FIG. As shown in the figure, the leaky coaxial cable 11 is provided with slots 16 in the outer conductor 15 at regular intervals. A signal propagating through the leaky coaxial cable 11 leaks from the slot 16 and predetermined communication is performed. The slots 16 are arranged so as to be located in front when viewed from the direction of arrow B shown in FIG. Therefore, the leaky wave is radiated most strongly in the direction opposite to the arrow B.

  If such a communication cable is wound around a drum and transported and pulled out at the site, it has a curl and it is hard and heavy, so it is difficult to fix the curl with a human hand while fixing it. Therefore, the tool is gripped and fixed by the support metal fitting while applying tension to both ends of the communication cable. Still, if some curl remains, the directionality of the slot is disturbed, and uniform emission of leaky waves cannot be performed.

  On the other hand, in the communication cable 1 of this embodiment, the bending rigidity of the high-rigidity support 10 is larger than the bending rigidity of the composite of the leaky coaxial cable 11 and the sheath 12 after the high-rigidity support 10 is removed. Designed to. Therefore, when the communication cable 1 is pulled out from the drum, the linearity of the entire communication cable 1 can be ensured without applying tension just like a convex. Therefore, the communication cable 1 may be fixed to the wall surface or the utility pole in order with the support metal fittings as it is pulled out from the drum. Even if exposed wiring is used, the aesthetics are good and stable electromagnetic field characteristics can be obtained.

FIG. 4 is a cross-sectional view of a communication cable according to the second embodiment.
In this communication cable 3, a plurality of high-rigidity supports 10 and leaky coaxial cables 11 are collectively covered with a sheath 12. If strong bending rigidity is given to one high-rigidity support body 10, the cross-sectional shape will become large like Example 1. FIG. On the other hand, as shown in this figure, by combining two or three or more high-rigidity supports 10, a support body having high bending rigidity as a whole can be configured. Accordingly, a communication cable having high bending rigidity can be obtained by combining relatively inexpensive materials.

FIG. 5 is a cross-sectional view of a communication cable according to the third embodiment, and FIG. 6 is a perspective view of a plate-like body 21 used for this.
In this communication cable 4, a plate-like body 21 having an arc-shaped cross section and a leaky coaxial cable 11 are integrally covered with a sheath 22. The plate-like body 21 has characteristics such as convex. That is, it can be wound around the drum and remains linear after being pulled out of the drum. As described above, the communication cable having a completely different cross-sectional shape from the first and second embodiments can also achieve the above-described effects. Also in this embodiment, when the material or cross-sectional shape of the high-rigidity support is selected so that the bending rigidity of the plate state 21 is larger than the rigidity of the composite of the leaky coaxial cable 11 and the sheath 22 excluding the plate-like body 21. Good.

FIG. 7 is an explanatory diagram of a method for laying the communication cable as described above.
The communication cable 1 shown in this figure is that of the first embodiment described with reference to FIG. The high-rigidity support 10 is gripped by the support fitting 25 via the sheath 12. Then, the bolt 26 is fastened and fixed, and this is fixed to a wall or a power pole (not shown). Thus, the communication cable 1 is supported and fixed. At this time, since the communication cable 1 as a whole maintains uniform linearity, the slot (FIG. 1) provided in the outer conductor of the leaky coaxial cable 11 is always accurately directed in one direction, and good communication is achieved. Is possible. In any of the following methods including this embodiment, the communication cable 1 is wound around a drum (not shown) with a bending radius that does not exceed the elastic limit of the high-rigidity support and is transported to the site. The stress applied to the high-rigidity support is released from the state of being wound around, and the slot of the leaky coaxial cable is laid linearly in a certain direction. The position of the slot may be any position on the top, bottom, left and right of the cable.

FIG. 8 is an explanatory diagram of a communication cable laying method according to the fifth embodiment.
As shown in the figure, in this example, the communication cable 1 is placed horizontally on the floor 28 as it is. Since the high-rigidity support 10 maintains linearity and the communication cable 1 does not have any curl as a whole, it can be laid linearly on the floor surface 28 while being pulled out from the drum. In a conventional leaky coaxial cable, it undulates on the cable floor 28. Fixing is required at a number of locations to prevent the lift. On the other hand, in the case of this embodiment, it is sufficient to fix it with the minimum support metal fittings, and it is not necessary to apply tension or carefully perform the straightening work. In addition, the slot is accurately directed to the left in the figure as a whole, and good communication can be performed.

FIG. 9 is an explanatory diagram of a communication cable laying method according to the sixth embodiment.
The communication cable 4 is that of the third embodiment described with reference to FIG. As shown in the figure, it is preferable to hold the whole using a support fitting 25 and fix it to a wall surface or a utility pole. Since the straightness of the cable is maintained and twisting is prevented, the slot of the leaky coaxial cable 11 is accurately positioned on the side surface of the cable. Therefore, when the communication cable 4 is supported and fixed, the direction of the slot becomes constant and stable communication is possible. Further, when the gripping force of the support fitting 25 is applied to the leaky coaxial cable 11, the plate state 21 is present, so that there is an effect that the strength is high and buckling can be prevented.

FIG. 10 is an explanatory diagram of a cable laying method according to the seventh embodiment.
If the high-rigidity support 10 and the leaky coaxial cable 11 are integrated with the sheath 12 as described above, the bending radius is limited at the direction changing portion such as the corner of the room. Therefore, in the example of this figure, the high-rigidity support 10 is cut at the direction changing portion C. The sheath 12 is also cut. The sheath 12 around the leaky coaxial cable 11 is left. In this way, only the portion of the leaky coaxial cable 11 is bent to a necessary bending radius and installed. In consideration of the allowable bending radius of the leaky coaxial cable 11, the leakage coaxial cable 11 is bent to a radius larger than the allowable bending radius. Thereby, the communication cable having the above characteristics can be continuously laid at various places.

FIG. 11 is a plan view showing a cable laying state when bent at a right angle.
As shown in this figure, before and after the direction changing portion C, the high-rigidity support 10 is gripped and fixed via the sheath 12 using the support fitting 25. Since the other portions maintain the linearity, they can be easily laid out linearly. Of course, it may be laid along a gently curved surface. In this way, the stress applied to the high-rigidity support is released from the state of being wound on the drum, and the slot of the leaky coaxial cable is laid linearly in a certain direction, while having a relatively small radius. At the corner, the high-rigidity support 10 can be cut to cope with it.

1 is a cross-sectional view of a communication cable according to Embodiment 1. FIG. 3 is a side view of the high-rigidity support 10. FIG. 2 is a side view of a leaky coaxial cable 11. FIG. 6 is a cross-sectional view of a communication cable according to Embodiment 2. FIG. 6 is a cross-sectional view of a communication cable of Example 3. FIG. It is a perspective view of the plate-shaped body 21 used for the communication cable of Example 3. It is explanatory drawing of the laying method of the cable for communication. It is explanatory drawing of the communication cable laying method of Example 5. FIG. It is explanatory drawing of the communication cable laying method of Example 6. FIG. It is explanatory drawing of the cable-laying method of Example 7. It is a top view which shows the cable laying state at the time of bending at right angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication cable 10 High-rigidity support body 11 Leaky coaxial cable 12 Sheath 13 Center conductor 14 Insulator 15 External conductor

Claims (2)

A highly rigid support and a leaky coaxial cable are integrally covered with a sheath,
Selecting the material or cross-sectional shape of the high-rigidity support so that the rigidity of the high-rigidity support is greater than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support; and The high-rigidity support body is a plate-shaped body having a circular arc cross section . A high-rigidity support and a leaky coaxial cable are integrally covered with a sheath, and the rigidity of the high-rigidity support is higher than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support. The communication cable with the material or cross-sectional shape of the high-rigidity support selected,
From the state wound on the drum, release the stress applied to the high-rigidity support, direct the slot of the leaky coaxial cable in a certain direction,
In a substantially straight laying portion, the high-rigidity support is gripped and fixed using a support fitting through the sheath without applying tension,
In the direction changing portion, a part of the high-rigidity support and the sheath is cut, and the leaky coaxial cable of the portion is bent and supported and fixed to a radius larger than an allowable bending radius. Method.

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