JPS5845245B2 - How to send out long low tension cables - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for delivering a long low-tension cable, and more particularly to a method for delivering a long low-tension cable suitable for laying a long optical cable.

Generally, when laying a cable in a conduit, the entire end of the cable is connected to a traction wire drawn into the duct, the traction wire is pulled with a winch, etc., and a cable delivery device is installed on the cable delivery side. A construction method is adopted in which the cable is sent out continuously.

By the way, in recent years, when laying cables in conduits, tunnels, etc., in order to improve work efficiency and reduce loss by reducing the number of connection points, one section is made longer and one connection point is extended from one connection point to the next connection point 1. The current distance of 150-250 m is being considered to be extended to 1-2 km.

When laying a long cable like this, it is practically impossible to send the cable within the allowable tension using the method described above, so as shown in Figure 1, multiple cable sending devices are installed along the cable laying line. 1a and 1b are installed at appropriate intervals, and these cable sending devices 1a and 1b
A method has been devised in which the cable 2 is sent out one by one and the pulling wire 3 connected to the tip of the cable is pulled by a winch 4.

However, although it is possible to install long lengths of general cables with copper conductors using this method, for example, in optical cables, external forces such as tension and bending during installation can cause non-uniform mechanical strain, resulting in loss. Hypotonic stress that tends to increase
There are problems with installing long pulls.

In other words, when one of the multiple cable delivery devices breaks down for some reason and the cable delivery function is abnormally reduced or lost, or when the connecting part between the cable and the traction wire breaks through a step or bend in the conduit. Excessive tension may suddenly be applied to the cable when attempting to pass through the cable, and the cable may not be able to be installed within the allowable characteristics of the cable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for delivering a long low-tension cable capable of stably delivering the long low-tension cable without deteriorating its properties.

The present invention provides a method for continuously sending out long low-tension cables using a plurality of cable sending devices installed at appropriate intervals, and a torque cut-off device is installed in the power transmission mechanism as each cable sending device. Use the one with
When a tension above a certain level is applied to the running cable, the torque cutoff device is activated to stop the operation of the cable sending device, and when the tension above the certain amount is released, the operation of the cable sending device is stopped. This is to restart it.

As the torque cut-off device, for example, a torque tender (trade name of Helanda Co., Ltd., USA) is used, and a second torque cut-off device is used.
Part A or B of the power transmission mechanism of the cable delivery device shown in the figure
will be deployed to the department.

Although not shown, in the torque tender, the input side ring and the output side ring are connected by a drive key supported by a torque spring, and when the load exceeds the rating, the drive key comes off and the input side ring The torque spring returns the drive key to its original position when the output ring and the output ring are separated and the overload is removed.

Such a device is installed, for example, between the motor 5 and the reducer 6 (A
) or the drive wheel ( ) that drives this reducer 6 and the endless belt.
sprocket) γ (part B).

The low tensile cable to which the method of the present invention is applied is not limited to cables, but can also be used for cables that undergo uneven mechanical strain due to external forces such as tension, bending, and impact during installation, which can cause wire breakage and increased loss. This applies to cables that are easy to connect.

As described above, according to the method of the present invention, a plurality of cable sending devices each equipped with a torque cut-off device are installed on a cable laying line to send out a cable, thereby applying tension above a certain level to a running cable. Since it is possible to prevent the addition of low tension cables, long lengths can be laid without deteriorating the properties of the low tension cable.

Further, according to the present invention, it is also possible to obtain the effect that the motor of the cable delivery device will not be burnt out due to the operation of the torque cutoff device.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the installation situation of long cables in the conduit,
FIG. 2 is an explanatory diagram of one embodiment of the present invention. 1a, 1b... Cable sending device, 2... Cable, 3... Traction wire, 5... Motor, 6... Reducer, 7... Drive wheel.

Claims (1)

[Claims] 1. For a method of continuously sending out long low-tension cables using a plurality of cable sending devices installed at appropriate intervals, each cable sending device has a torque cutoff device in the power transmission mechanism. When a tension above a certain level is applied to the running cable, the torque cut-off device is activated to stop the operation of the cable sending device, and when the tension above the certain amount is released, the cable is sent out. A method for delivering a long hypotonic cable, characterized in that the operation of the device is restarted.