JP2001086614A - Cable laying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a cable laying method by continuously inserting an optical cable for a long distance into a conduit without damaging an optical fiber. SOLUTION: Air flow is generated within a conduit 1 by providing a cable holding mechanism 2 that can send a cable A in the specified velocity while holding it is provided in one opening 1a of the conduit 1 and by communicating an absorbing apparatus 3 having an absorbing force adjusting means with the other opening 1b of the conduit 1. The cable A is floated with this air flow and the cable is sent in the predetermined velocity with the cable holding mechanism 2. This cable is inserted into the existing conduit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of laying a cable by inserting a communication cable such as an optical cable into an existing pipeline, and more particularly to a method of laying a cable through which a cable can be inserted over a long extension. Concerning the construction method.

[0002]

2. Description of the Related Art In recent years, due to the diversification of information and communication, communication cables are often laid underground or the like. As one example, conventionally, telephone lines laid between telephone poles erected on the ground are laid in underground pipes.

[0003] As one of the transitions of underground laying of such a communication cable, laying an optical cable in an information box conduit has been performed. In this information box, a plurality of pipelines are laid in advance over a relatively long distance such as a gutter on a national road or under an expressway. An optical cable is laid in one of the pipelines over a long distance.

[0004]

When an optical cable is to be inserted over a long distance, frictional resistance between the inner surface of the pipe to be laid and the cable becomes a serious problem. If the optical cable is pulled in, while the cable is inserted, that is, while moving on the inner surface of the tube, a kinetic friction coefficient is applied between the cable and the inner surface of the tube, and the optical cable is pulled in while a frictional force is applied. However, if the drawing operation is temporarily interrupted for some reason and the drawing operation is restarted again, a coefficient of static friction is applied between the cable and the inner surface of the pipe, and a huge drawing force is required to move the cable. If the traction force is increased by using a device such as a winch and the cable is forcibly pulled in, there is a risk that the optical fiber in the optical cable may be torn.

It is an object of the present invention to provide a cable laying method capable of continuously inserting an optical cable over a long distance in a pipeline without damaging the optical fiber.

[0006]

In order to achieve this object, the invention according to claim 1 is a method for laying a cable in an existing pipeline by laying the cable in the pipeline. A cable holding mechanism for feeding the cable at a required speed while holding the cable at one end opening of the pipeline is provided, and a suction device having a suction force adjusting unit is communicated with the other end opening of the pipeline, An airflow is generated in the pipe, the cable is floated by the airflow, the cable is sent out at a required speed by the cable holding mechanism, and the cable is inserted into the existing pipe.

According to a second aspect of the present invention, an airflow receiving member is provided at an end of the cable for receiving an airflow flowing through the conduit, and a predetermined tension is applied to the cable to make the cable a floating state. Sending out the cable at a required speed by the cable holding mechanism, and inserting the cable into an existing pipe.

According to a third aspect of the present invention, there is provided a method for laying a cable in an existing pipeline by inserting the cable into the existing pipeline, wherein the cable is closed at a tip end of the cable. A cable holding mechanism for feeding the cable at a required speed while holding the cable at one end opening of the conduit, and a suction device communicating with the other end opening of the conduit. Then, a negative pressure is generated between the elastic body and the other end opening, and the elastic body and the cable are connected to the one end opening of the pipe by the combined force of the negative pressure and the cable feeding force by the cable holding mechanism. From the other end to the opening of the other end to carry out cable passage.

According to a fourth aspect of the present invention, when the negative pressure exceeds a predetermined value, the elastic body is elastically deformed to release the blockage in the conduit, and the negative pressure is reduced. It is characterized in that, when the value is reduced to a predetermined value or less, the pipeline is restored and the inside of the pipeline is closed again.

[0010]

According to the first aspect of the present invention, the cable is inserted into the pipeline while being held by the cable holding mechanism from the one end opening of the pipeline. Then, a suction device is communicated with the other end opening of the pipeline to generate an air flow in the pipeline. Therefore, since the cable end is held by the cable holding mechanism, the cable floats due to the high-speed airflow, and the cable does not come into contact with the inner surface of the pipeline. Then, the cable is sent out at a required speed by the cable holding mechanism in a floating state, and inserted into the pipeline.

Here, the air flow is generated by negative pressure suction, so that the air flow has good penetrability. As a reason, for example, when there is a bent portion in the pipe, in the case of an airflow due to positive pressure, since the straight flow is excellent, the airflow collides with the bent portion of the pipe, and the airflow becomes turbulent, Therefore, the cable conveyed by the air flow also collides with the inner surface of the pipeline,
It is inserted. In contrast, in the case of airflow generated by negative pressure suction, the airflow flows along the insertion path, so even if there is a bent part, it will flow smoothly, and the cable will not contact the inner surface of the pipeline due to turbulent flow. Absent.

According to the second aspect of the present invention, an airflow receiving member is provided at the end of the cable. Therefore, due to airflow,
The airflow receiving member and the cable are pulled in the airflow direction, and a required tension is applied to the cable. Therefore, the floating of the cable becomes more reliable, and the cable is inserted into the pipeline without contacting the inner surface of the pipeline, that is, without receiving frictional resistance.

According to the third aspect of the present invention, a cable having an elastic body such as a sponge attached to the end thereof is inserted from one end opening of the conduit, and the cable is directed toward the other end of the conduit by the cable holding mechanism. Send out. On the other hand, a suction device is communicated with the other end opening of the pipeline to generate a negative pressure between the elastic body and the other end opening of the pipeline. Then, due to the negative pressure, the elastic body moves to the other end opening side of the conduit, and the cable is also moved by being pulled by the elastic body. Then, by adjusting the suction force to match the moving speed of the elastic body with the sending speed of the cable, an appropriate tension is applied to the cable so that the cable does not touch the inner surface of the pipe, and the inner surface of the pipe and the cable are connected. In order to reduce the frictional resistance between the two.

According to the invention described in claim 4, the elastic body includes:
As if acting like a pressure regulating valve, the negative pressure does not rise excessively.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is an explanatory view showing a first embodiment of the present invention.
As shown in the drawing, a cable holding mechanism 2 is disposed on the first opening 1a side of the existing pipeline 1, and the second opening 1b of the existing pipeline 1 is provided.
The suction device 3 is connected to the side. Here, as shown in FIG. 2, the cable holding mechanism 2 includes a pair of left and right rollers 21 that rotate at a required speed while biting the cable, and are disposed in front and back.
It has the function of sending out. The cable holding mechanism 2 is provided with a speed controller 22 for adjusting the rotation speed of the roller 21. The speed controller 22 adjusts the rotation speed in accordance with the inner diameter and length of the insertion pipe to reduce the insertion speed. Controlling.

As shown in FIG. 1, when the suction device 3 is driven, a high-speed airflow is generated in the pipe 1. Since the cable A is held by the cable holding mechanism 2, the cable A is not inserted before the rotation of the roller 21.
In this state, the cable is in a floating state without contacting the inner surface of the pipeline 1 by the high-speed airflow. Then, by rotating the roller 21 of the cable holding mechanism 2, the cable A is sent out into the pipeline 1 at a required speed, and is inserted while floating.

Here, the penetration of the airflow generated by the suction device 3 will be described. In the method of the present invention,
This is a negative pressure suction by the suction device 3, and has better penetrability than positive pressure pressure feeding. The reason is that, for example, when there is a bent portion in the existing pipeline 1, in the case of an airflow due to positive pressure, the airflow collides with the bent portion of the pipeline 1 because the straight flow is excellent, and the airflow becomes turbulent. Therefore, the cable A conveyed by the air flow is also inserted while colliding with the inner surface of the pipeline 1. On the other hand, in the case of airflow generated by negative pressure suction, since airflow flows along the insertion path, even if there is a bent portion, the airflow flows smoothly and the cable A comes into contact with the inner surface of the pipe 1 due to turbulent flow. Never.

Next, the case where the airflow receiving member 4 is provided at the end of the cable A will be described. As shown in FIG. 3, the airflow receiving member 4 has a weight disposed at the tip and is formed in an umbrella shape toward the rear, and receives the airflow flowing through the pipeline. Then, when the suction device 3 is driven, a high-speed airflow is generated in the pipe line 1 and is in a floating state. When the airflow receiving member 4 receives the airflow, a required tension is applied to the cable A. As a result, the cable A can be more reliably maintained in a floating state, and the cable can be reliably inserted into the pipeline 1 by the cable feeding force by the cable holding mechanism 2 and the tension.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the pipe to be inserted is long and it is difficult to maintain the floating only by the airflow, and a predetermined value of tension is applied to the cable to maintain the floating of the cable. As shown in FIG. 4, the elastic body 5 is connected to the distal end of the cable A, and the cable is introduced into the pipeline 1. This elastic body 5
Is formed of a sponge or the like, is formed in a spherical shape whose outer diameter is slightly larger than the inner diameter of the pipe, and is elastically deformed into a shell shape when a required pressure or more is applied.

As shown in FIG. 4, first, the cable A to which the elastic body 5 is connected at the distal end is introduced into the pipeline from the first opening 1a of the existing pipeline 1 via the cable holding mechanism 2. And a suction device 3 communicating with the second opening 1b of the existing pipeline 1.
Drive. At this time, the cable holding mechanism 2 is not driven,
The cable A is held. Then, the pressure inside the pipe 1 is gradually reduced to a predetermined value, and when the pressure reaches a predetermined value, the elastic body 5 is elastically deformed into a shell shape as shown by a dashed line in the figure, and the airflow flows through the pipe 1. At this time, a required tension is applied to the cable A, and the cable A is in a taut state and is surely floating. However, the required tension is much smaller than the breaking tension of the cable A. In this state, the cable holding mechanism 2 is driven to send out the cable A into the pipeline at a required speed. At this time, even if the cable A is inserted over a long distance and the weight of the cable A is slightly increased, the required tension is always applied to the cable A. Without touching
It is possible to insert the cable in a floating state.

[0021]

As is clear from the embodiments described above, according to the present invention, when a cable is inserted into a pipeline, the cable is inserted in a floating state in the pipeline, whereby the pipe is inserted. Reduce the frictional resistance between the road inner surface and the cable,
By lowering the insertion resistance of the cable, the cable can be inserted over a long distance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a cable holding mechanism.

FIG. 3 is an explanatory diagram showing a modification of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Existing pipeline 1a 1st opening 1b 2nd opening 2 Cable holding mechanism 21 Roller 22 Speed controller 3 Suction device 4 Air flow receiving member 5 Elastic body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Suehiro 3-23-14 Takanawa, Minato-ku, Tokyo Inside Japan COMSYS Corporation (72) Inventor Nobukatsu Ike 1-10-6 Takaban, Meguro-ku, Tokyo Inside Hako Co., Ltd. (72) Inventor Hiroaki Kaneko 1-10-6 Takaban, Meguro-ku, Tokyo Tokyo Incorporation (72) Toshio Nakagawa 1-10-6 Takaban, Meguro-ku, Tokyo Co., Ltd. Inside Hako (72) Inventor Junta Sakurai 1-10-6 Takaban, Meguro-ku, Tokyo Inside Hako Co., Ltd. (72) Inventor Takeomi Miura 4-720-20 Toyo, Koto-ku, Tokyo Inside Doi Corporation

Claims (4)

[Claims] A method of laying a cable in an existing pipeline by inserting the cable into the existing pipeline, wherein the cable is held at an opening at one end of the pipeline at a required speed. A cable holding mechanism for sending out is provided, and a suction device provided with a suction force adjusting means is communicated with the other end opening of the pipe to generate an airflow in the pipe, and the cable is floated by the airflow. Along with
A cable laying method, wherein the cable is sent out at a required speed by the cable holding mechanism, and the cable is inserted into an existing pipe. 2. An airflow receiving member for receiving an airflow circulating in the conduit is provided at a distal end of the cable, and the cable is floated by applying a required tension to the cable, and the cable is held by the cable holding mechanism. The cable laying method according to claim 1, wherein the cable is sent out at a required speed, and the cable is inserted into an existing pipe. 3. A method of laying a cable in an existing pipeline by inserting the cable into the existing pipeline, wherein an elastic body that moves while closing the pipeline is provided at a distal end portion of the cable. A cable holding mechanism for feeding the cable at a required speed while holding the cable at one end opening of the conduit, and a suction device communicating with the other end opening of the conduit, and A negative pressure is generated between the other end opening and the elastic body and the cable from the one end opening to the other end opening of the conduit by the combined force of the negative pressure and the cable feeding force by the cable holding mechanism. A cable laying method characterized in that the cable is moved by moving it toward the cable. 4. The elastic body, when the negative pressure exceeds a predetermined value, the elastic body is elastically deformed to release the blockage in the conduit, and the negative pressure is reduced to a predetermined value or less. 4. The cable laying method according to claim 3, wherein the cable laying method is configured such that the pipe is restored and the inside of the pipeline is closed again.