JPS5953767B2 - Cable installation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of laying a cable through a plurality of manholes from conduit to conduit using a towline and a cable take-off device.

When installing communication cables, optical fiber cables, etc., which are long and weak against tension, in a conduit, in order to reduce the tension applied to the cables, it is necessary to not only pull the ends of the cables with a pull rope, but also to In this method, a method is adopted in which a cable is pulled up by a cable pulling device such as an endless belt type or a roller type, and the cable is sent forward.

The above-mentioned pulling device is installed inside the manhole through which the cable passes, and during installation work, the pulling device first takes over the tow rope connected to the tip of the cable, guides the cable tip into the manhole, and then guides the cable tip into the manhole. The prepared tow line is attached to the inside of the pipe and the pulling line is started towards the adjacent manhole.

That is, the cable is clamped by a cable pulling device installed in the manhole, and the cable is sent out to the next conduit together with a tow rope.

In this case, the cable load at the rear of the pulling device is not transmitted to the cable at the front, and the cable can be laid with relatively low tension.

When performing the above-mentioned cable laying work, as shown in FIG. Stop the drive, widen the set clamping interval of the device 4,
It is necessary to forcibly feed the cable 2 manually and drive the take-off device 4 again.

This is because the outside diameter of the cable 2 is generally larger than the outside diameter of the towline 1, and there is a step where the towline 1 and cable 2 are connected, so this is adjusted in advance according to the outside diameter of the towline. This is because at the set clamping interval, the cable tip end collides with the incoming side of the take-off device and stops at that location, making it impossible to take off the cable continuously.

Further, since the clamping force also changes significantly if the outer diameter differs greatly, it is also necessary to increase the set clamping interval using an adjustment device attached to the device.

In other words, the pulling device transports the cable to the cable installation location,
Due to the narrowness of the work space, they are generally made smaller and lighter in weight, and the drive source motor is also of a low output type.

Therefore, an excessive load is applied to the drive source via the endless belt, rollers, or other clamping members, resulting in the cable pulling device stopping.

The present invention has been made based on the above-mentioned circumstances, and makes it possible to continuously pull the towline and cable without stopping the cable pulling device, thereby shortening the cable installation time and improving work efficiency. Provides a cable installation method.

An embodiment of the present invention will be described below with reference to the drawings.

1. In FIG. 2, similarly to FIG. 1, the towline 10 is connected to the tip of the cable 11 to be laid using the connector 12, and after inserting one end of the towline 1 into the cable pulling device 13,
This pulling device 13 is driven to pull the cable 11 via the tow rope 10.

In the above case, the towline 10 coupled to the cable 11 is configured as follows.

That is, the towline 10 has the same diameter as before,
The outer diameter of the cable 11 is made to be different in the length direction, and in particular, the outer diameter of the cable 11 and the outer diameter D' of the end of the tow rope 10 connected to the tip of the cable 11 are made approximately equal, and the cable is caught in the pulling device 13. A feature is that the outer diameter d of the tip of the towline 10 is reduced.

The towline 10 shown in FIG. 2 shows an embodiment in which the outer diameter is tapered and can be divided into a plurality of parts.

That is, the dragline 10 is made up of five unit ropes 10a each having a length of about 1 m, for example, connected together.

For example, a coupling device as shown in FIG. 3 is provided at the coupling portion of each unit rope 10a.

This coupling device consists of a female coupling device 14 attached to the reduced diameter end 10b of the unit rope 10a and an enlarged diameter end 10C of the unit rope 10a.
The male connector 15 and the female connector 14 of the unit rope 10a are jointed to each other, and a bolt 18 is inserted into the through hole 16° 17 and fastened with a nut 19. .

Figures 4 and 5 show other embodiments of the towline.
In FIG. 4, the unit ropes 10a are not formed into a tapered shape, but the outer diameters of the unit ropes 10a are made different in steps.

Further, the towline 10 shown in FIG. 5 does not have a unit rope 10a, but is formed in a continuous tape shape.

In this case as well, the outer diameter of the enlarged diameter end is approximately equal to the outer diameter of the cable to be laid.

The shape of the towline is not limited to the above-mentioned shape, and various shapes such as a tapered shape with a rectangular cross section and a shape with a flattened diameter side can be considered.

In short, the wall thickness to be held by the cable pulling device at one end of the towline is approximately equal to the outer diameter of the cable, and the wall thickness is reduced asymptotically or stepwise toward the other end. That's fine.

In addition, identification marks are attached to the reduced diameter side of the towline, i.e., the end of the end that is inserted into the cable pulling device, by color or other means, so that the current position of the cable end connected to the towline can be recognized, and the operator can take the cable away. It serves as a notice of when to start adjusting the clamping interval of the device.

Next, a cable installation method using the towline having the above configuration will be explained.

First, a towline 10 having an enlarged diameter end with an outer diameter approximately equal to the outer diameter of the cable 11 to be laid is prepared, the enlarged diameter end of this towline 10 and the end of the cable 11 are connected, and the towline 10 is After the reduced diameter end of the rope is caught in the cable pulling device 13 installed in the manhole, the cable pulling device 13 is adjusted to an appropriate clamping interval, that is, an appropriate pressing force for holding the reduced diameter end of the tow rope. drive

Then, as the towline 10 moves forward, the interval at which the cable pulling device should clamp increases asymptotically or stepwise, and the operator responds accordingly by turning the bundle of the cable pulling device 13 to set the clamping distance. By gradually widening the gap, it becomes possible to smoothly and continuously pull the cable 11 through the enlarged diameter end of the towline 10.

Therefore, it is no longer necessary to stop the drive of the cable pulling device 13 when the cable arrives just before the input side of the cable pulling device 13 and manually force the cable to be caught in the cable pulling device 13 as in the conventional work. This results in a significant reduction in cable installation work time.
It is possible to improve workability in narrow spaces such as manholes.

In addition, when using a towline with multiple unit ropes connected together as shown in Figure 2, separate the towline at an appropriate point depending on the outer diameter of the cable to be laid, and make sure that the outer diameters of both ropes match. By the way, it can be used and is highly versatile.

Further, in the embodiments of the present invention, a cable pulling device that holds the cable in the upper and lower directions is illustrated, but the present invention is of course not limited to this, and can also be applied to a cable pulling device that holds the cable in the horizontal direction. .

Furthermore, the wall thickness of the tow rope does not change over the entire area as in the embodiment of the present invention, but the wall thickness gradually changes over a few meters near the end of the long tow rope. It is also possible to use a material that has been processed so that it approaches

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the conventional cable laying method, FIG. 2 is an explanatory diagram showing the cable laying method of the present invention, and FIG. 3 is an explanatory diagram showing the cable laying method of the present invention.
Enlarged view of the connection points of each unit rope that makes up the towline, No. 4
5 and 5 are partially cutaway external views showing each embodiment of the towline used in the present invention. DESCRIPTION OF SYMBOLS 10... Pull rope, 10a... Unit rope, 11... Cable, 12... Coupling device, 13... Cable pulling device.

Claims (1)

[Scope of Claims] 1. In a cable laying method in which a towline inserted into a conduit and a cable to be laid are connected, and the towline and the cable are pulled in one direction by a cable pulling device, the towline includes: , asymptotically or stepwise changing the wall thickness held by the cable pulling device from the tip end on the incoming side to the cable pulling device toward the rear cable coupling part side so that the thickness approaches the outer diameter of the cable to be laid. A cable laying method characterized by using a rope. 2. The cable laying method according to claim 1, characterized in that a tapered towline is used in which the outer diameter of the towline is smoothly and asymptotically changed in the length direction. 3. The cable laying method according to claim 1, characterized in that a towline is used in which the outside diameter of the towline is changed in stages. 4. The cable laying method according to claim 1, characterized in that the towline is a towline that can be divided into a plurality of parts.