JPS6236444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cable installation method, and particularly to a cable installation method suitable for cases where the cable length is long or the installation route is curved.

Communication cables and power cables are usually installed in underground conduits, aboveground pits, or overhead utility poles. In this case, it is advantageous for the length of one cable to be as long as possible, also from the viewpoint of reducing the number of cable connection points. However, when the cable length is long, a large tensile force is applied to the cable due to the frictional force between the cable and the conduit during installation.
Cables may be damaged. As a means to solve such problems,
The publication discloses a method for reducing tension near the tip of the cable by installing an endless belt type auxiliary puller in the middle of the conduit so that the cable is pulled not only at the tip but also in the middle. ing. However, this method requires an endless belt type auxiliary pulling machine in addition to the main pulling machine installed at the tip of the laying route, and this auxiliary pulling machine needs to be linked with the main pulling machine. However, this method has the disadvantage that it not only increases costs but also makes the work troublesome.

In addition, even if the length of a single cable is short, if the installation route is bent, the cable will be subjected to straining, and a large tensile force will still be applied to the cable. A similar problem arises.

The purpose of the present invention is to eliminate the above-mentioned drawbacks,
To provide a cable laying method that can reduce the tensile force applied to the cable even when the cable length is long or the laying route is bent, and does not require a special machine such as an auxiliary pulling machine. .

According to the invention, this purpose is to install a drum on which the cable to be laid is wound at an intermediate point of the laying section, to draw the cable from this drum and to lay it from said intermediate point to one end of the laying section. ,
Thereafter, the remaining cable is withdrawn from said drum and accumulated in the shape of a figure 8 at said intermediate point, and finally, the cable is withdrawn from this figure 8 shaped cable accumulation and is transferred from said intermediate point to the other part of the laid section. This is achieved by laying it all the way to the edge.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the figure, 1A to 1E are manholes, 2A to 1E are manholes, and 2A to 1E are manholes.
2D is a conduit that communicates between manholes, and L is a section where one cable is to be laid.

First, as shown in FIG. 1, a drum 4 around which a long cable 3 to be laid is wound is installed near a manhole 1C located in the middle of a laying section L. Although the drum 4 is not shown, it is rotatably supported by a drum support base. In addition, take-off machines 5A and 5B are installed near the manholes 1A and 1E at both ends of the laying section L, respectively. Next, intermediate manhole 1
Pipe line 2A, 2 from C to manhole 1A at one end
Pass the lead wire 6A for cable pulling through B,
The tip of the cable 3 is connected to the rear end of the lead wire 6A. In this state, as shown in Figure 2,
The cable 3 is pulled out from the drum 4 by taking the lead wire 6A with the take-off machine 5A, and is laid between the intermediate manhole 1C and the manhole 1A at one end.

Thereafter, as shown in FIGS. 3 and 6, the remaining cables 3 are pulled out from the drum 4, and the cables 3 are accumulated in a figure 8 shape at that point, forming a figure 8 cable accumulation section 7. Next, the pipe line 2 from the intermediate manhole 1C to the manhole 1E at the other end
A lead wire 6B is passed through C and 2D, and the rear end of the cable 3 is connected to the lead wire 6B. In this state, as shown in FIG.
The cable 3 is pulled out from the figure-of-eight cable accumulation section 7 by being picked up by the pulling machine 5B, and laid between the intermediate manhole 1C and the manhole 1E at the other end. When this installation is completed, the cable will be in a state as shown in FIG. 5, and the cable installation over the entire length of the installation section L will be completed.

According to this method, compared to the conventional method in which the cable is pulled from one end of the cable to the other in one go, the cable is divided into two sections, so the pulling force applied to the cable is reduced to about half of the conventional method. It can be reduced to about 1. In addition, since the cables are accumulated in a figure-8 shape at intermediate points, the cables do not get twisted when they are accumulated or pulled out, allowing for smooth cable installation. .

In the above embodiments, the case of cable conduit installation has been described, but the present invention can be similarly applied to cases of pit installation, overhead installation, etc.

Note that the midpoint of the laying section does not need to be exactly one half of the laying section, and may be appropriately selected depending on the situation at the laying site.

Further, in the above embodiment, the case where the laying route is straight has been described, but if the laying route is curved in the middle, it is preferable to install the drum at the bending point.

As explained above, the present invention installs a drum at the middle point of a laying section, lays the cable from there toward one end, pulls out the cable from the drum, accumulates it at the middle point, and then directs it to the other end. Since the cable is laid using the cables, the length of each cable installation can be shortened, and the tensile force of the cable can be significantly reduced compared to the conventional method. Therefore, it is extremely effective when the cable length is long or the installation route is curved. Further, when the cables pulled out from the drum are accumulated at the intermediate point, the cables are accumulated in a figure 8 shape, so that the cables can be laid smoothly without twisting the cables.

[Brief explanation of the drawing]

Figures 1 to 5 are cross-sectional views showing each step of a laying method according to an embodiment of the present invention, and Figure 6 is a perspective view showing a state in which cables are accumulated in a figure 8 shape in one step of the laying method. It is. 1A to 1E... Manhole, 2A to 2D... Conduit, 3... Cable, 4... Drum, 5A, 5B
...Taking machine, 6A, 6B...Lead wire, 7...
...Figure-8 storage section, L...layment section.

Claims (1)

[Claims] 1. Install a drum around which the cable to be laid is wound at the middle point of the laying section, pull out the cable from this drum and lay it from the middle point to one end of the laying section, and then remove the remaining cable from the drum. The method is characterized in that the cable is pulled out and accumulated at the intermediate point in a figure-eight shape, and finally the cable is pulled out from this figure-eight-shaped cable accumulation part and laid from the intermediate point to the other end of the laying section. Cable installation method.