JPH0785614B2 - Cable laying method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a cable laying method, and more particularly to a cable laying method using a towing device and a shunt line controller.

(Technical background of the invention) When laying a conduit such as a communication cable or an optical fiber cable, the cable is connected to a towing rope, the towing rope is passed through the conduit and towed by a towing device, and a tension detecting device is also used. Detects the tension of the tow rope by, and when the tension reaches the upper limit, stop only the tail control machine,
As a result, the tow rope is slipped on the capstan drum of the tow device, and the tension thereof is reduced. Then, after that, the tension of the tow rope is
When the tension decreased to 90% of the upper limit), the tail line controller was driven again.

(Problems of the background art) However, when keeping the drive of the towing device and stopping only the tail line control device in this way, the towing rope that was stretched mainly due to the upper limit tension returns to the original length dimension. Since the tension of the cable itself is only lowered, the cable is always kept at the upper limit tension, and there is a possibility that the cable is applied with a tension equal to or higher than the upper limit tension at the time of re-driving the tail line controller.

Also, if a failure occurs in the laying route such as a pipeline or the connecting portion between the towing rope and the cable, the tension of the towing rope increases, but as mentioned above, it is not enough to simply stop and restart the tail line controller. It is impossible to know whether a failure has occurred. Therefore, the operator conventionally determines whether or not the tail line control device is repeatedly stopped and restarted, and if it is repeated, the towing device and the tail line control device are reversely driven to adjust the tension of the tow rope. When the towing rope is towed after being removed by driving it in the normal direction, it is again determined whether or not the tension reaches the upper limit tension, and whether or not a failure has occurred is detected by this. However, if the pulling device is driven in the reverse and forward rotation after determining whether or not the tail line controller has repeatedly stopped and restarted in this way, it takes a lot of time to detect the occurrence of a fault and the cable is There is a risk that tension more than the upper limit tension may be applied repeatedly,
Not preferable.

(Object of the Invention) An object of the present invention is to provide a method for laying a cable without applying a tension equal to or more than the upper limit tension to the cable, and moreover, by instantaneously determining whether or not a fault has occurred in a laying route or the like. To provide.

(Summary of the Invention) The present invention reduces the traction speed of a traction device when a set tension equal to or lower than the upper limit tension is applied to a cable to continue the traction of the cable, and when the upper limit tension is applied, the traction device and the tail handle. It is characterized in that the line controller is driven in the reverse direction to apply the lower limit tension to the cable, and the traction device and the tail line controller are again driven in the normal direction.

Embodiments of the Invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example in which the method of the present invention is applied to laying a pipeline, and a tension detecting device 3 is installed on a step 2 at the entrance of a manhole 1. The tension detecting device 3 includes guide rollers 5 and 6 rotatably supported on both ends of the frame body 4. A substantially U-shaped mounting member 7 is provided at the center of the frame body 4, and a tension detector 8 is mounted on the lower surface of the upper wall portion of the mounting member 7. Brackets 9, 9 from the tension detector 8
(Only one side is shown in the drawing) extends downward, and a detection roller 10 is rotatably supported between the brackets 9 and 9. A locking plate 11 is fixed to the lower end of the frame body 4, and
A locking pin 11 a projecting downward from 11 is engaged with the lid receiving groove 1 a of the manhole 1. A fixing bolt 12 is screwed into the lower end of the locking plate 11, and the tip of the fixing bolt 12 is brought into contact with the inner wall surface 1b of the manhole 1, whereby the tension detecting device 3 is fixed near the entrance of the manhole 1. There is.

A clamp 13 as a fixing means is attached to the upper surface of the attachment member 7 of the tension detecting device 3. The clamp 13 clamps a plate 14a attached to the lower surface of the tail line controller 14, whereby the tail line controller 14 is fixed.
The tail line controller 14 has a capstan 15 which is rotationally driven by a motor, and a presser roller 16 which is located above the capstan 15, and the presser roller 16 is moved up and down by adjustment of an adjusting unit 17. , Apply a predetermined pressing force to the tow rope. A winch 18 is installed near the tension detecting device 3. This winch 18 is equipped with a capstan drum 19 which is rotationally driven by a motor, and, as will be described later, a tail line controller
It is controlled by the controller 20 together with 14.

By the way, when the optical fiber cable 21 is laid in a pipeline, the optical fiber cable 21 is connected to the tow rope 22 via the untwisting device 23, and the tow rope 22 is connected to the outside via the guide pulley 24 in the manhole 1. And pass it between the guide roller 5, the detection roller 10 and the other guide roller 6 of the tension detecting device 3, and wind it around the capstan drum 19 of the winch 18 several times, and further around the capstan 15 of the tail line controller 14. The winding start end is fixed to the winding drum 25 by winding several times. Therefore, when the winch 18 and the sword line controller 14 are driven in the normal direction, the tow rope 22 is towed, so that the optical fiber cable 21 is passed through the conduit 26 and laid.

Next, the laying method of the present invention will be described.

That is, as described above, the winch 18 and the sword line controller 14
When is driven, tension is applied to the tow rope 22, so that the detection roller 10 moves upward, and the tension detector 8 supplies a tension detection signal to the controller 20.

Now, in the method of the present invention, as shown in FIG.
It is detected by the tension detection signal from the tension detector 8 that the set tension T ₂ having a magnitude of 70% with respect to T _{1 is applied} to the tow rope 22, and the motor of the winch 18 is controlled by the control signal of the controller 20. To reduce the speed of rotation and reduce its traction speed. Then, the towing operation of the towing rope 22 is continued at this towing speed. Therefore, since the optical fiber cable 21 can be towed while almost applying the set tension T ₂ ,
Problems such as deterioration of the characteristics do not occur.

After that, if the tension of the tow rope 22 rises for some reason and a tension detection signal indicating the upper limit tension T ₂ is supplied from the tension detector 8, the winch is activated by the control signal of the control device 20.
18 and the motors of the tail line controller 14 are driven in reverse. Then, when it is detected by the tension detection signal from the tension detector 8 that the tension of the towing rope 22 has reached the lower limit tension T ₀ (the tension is 0) by this reverse rotation drive, the control device 20
In response to the control signal, the motors of the winch 18 and the sword line controller 14 are again driven in the forward direction to pull the tow rope 22.

When the towing operation of the tow rope 22 is restarted, the tension of the tow rope 22 increases, and the tension detecting device 8 again causes the upper limit tension to rise.
When the tension detection signal indicating T ₂ is supplied, the control device 20 similarly drives the winch 18 and the motor of the tail line controller 14 in the reverse direction, and also drives the motor in the normal direction at the lower limit tension. When this operation continues at least twice, the control device 20 determines that a failure has occurred in the laying rule of the pipeline 26, the untwisting device 23, etc., and reverses the winch 18 and the sword line controller 14. Drive and stop. Therefore, it is possible to automatically and instantly know that a failure has occurred. Also winch 18
Since these components are driven in the reverse direction and then in the normal direction, tension is gradually applied to the optical fiber cable 21, and therefore its characteristics are not deteriorated.

Further, when the tension of the towing rope 22 increases to the set tension T ₂ by restarting the towing work of the towing rope 22, the control device 20
Reduces the rotation speed of the motor of the winch 18 by its control, but in this case, if the towing rope 22 is held at the set tension T ₂ , the control device 20 causes the towing operation of the towing rope 22 to continue. The winch 18 and the tail line controller 14 are driven and controlled.

In the above embodiment, the set tension T ₂ is 80% of the upper limit tension T ₁ .
% Tension, and the lower limit tension T ₀ is the upper limit tension T ₁
The tension may be set to 40% or less.

(Effect of the invention) According to the present invention, when the set tension equal to or lower than the upper limit tension is applied to the cable, the towing speed of the towing device is reduced to continue the cable towing work, and then the towing is performed when the upper limit tension is applied. By lowering the lower limit tension to the cable by driving the device and the sword line control in reverse and driving the traction device and the sword line controller in the forward direction again, it is possible to pull the cable while always applying the set tension to the cable. It is possible to know that a trouble has occurred in the laying route and the like by repeating the reverse rotation and forward rotation of the towing device and the like. Therefore,
It is possible to lay a cable without deteriorating the characteristics and instantaneously determining whether or not a failure has occurred.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a pipeline laying mode to which the laying method according to the present invention is applied, and FIG. 2 is a waveform diagram showing the relationship between control of equipment and tension. 1 …… Manhole, 8 …… Tension detection device, 14 …… Handline control device, 18 …… Winch, 20 …… Control device, 21 …… Optical fiber cable, 22 …… Towing rope.

Claims (1)

[Claims] 1. A method of laying a cable, wherein a cable to be laid is towed by a towing device, and the tension of the cable is lowered via a tail line controller when an upper limit tension is applied to the cable. When the set tension equal to or lower than the upper limit tension is applied to the cable, the towing speed of the towing device is reduced to continue the towing of the cable, and then when the upper limit tension is applied to the cable, the towing device and the left hand line controller are A method for laying a cable, which comprises driving the cable in a reverse direction to apply a lower limit tension to the cable, and again driving the traction device and the tail line controller in the normal direction.