JPS63171105A - Pulling part of covered cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is for installing a coated cable with high bending rigidity in a closed installation route with many narrow parts such as a conduit, a bend, a stepped part, etc. [Prior art] Related to a pulling section of a coated cable for laying a cable The conventional technology will be explained with reference to FIGS. 2 and 3.

For example, a coated cable with high bending rigidity such as a high voltage plastic coated cable (hereinafter simply referred to as "cable 1") 1
When installing the cable 1 into the conduit 10, if the tip of the cable 1 is bent due to drum winding, etc., the cable 1
The cable 1 may not be able to be installed because the distal end portion of the cable 1 gets caught in the stepped portion 12, bent portion 13, etc. in the conduit 10.

In such cases, it has been common practice to lay the cable 1 with J2, the bend of which is removed from the tip of the cable, before the cable is laid, using a mechanical method or the like.

There is also a method in which the cable 1 is laid by applying a pencil coating to the tip of the cable 1 to a required length to reduce the rigidity of the tip and make the cable 1 more bendable.

[Problems to be Solved by the Invention] However, in the conventional method described above, it takes a lot of time and effort to straighten the bend, the cable 1 is easily damaged over a considerable length, or it is difficult to remove the cable after it is laid. There are disadvantages such as the large number of parts.

Furthermore, even if the bend at the tip of the cable 1 is corrected or the coating on the tip is made easier to bend by applying pencil processing, the cable 1 may have difficulty passing through the stepped portion 12 etc. due to lack of flexibility. be.

The present invention has been made to solve these conventional problems, and provides a new cable traction section that allows the cable 1 to be easily laid even in the conduit 10, etc., where human hands cannot reach at all. It is intended to be

The cable pulling section of the present invention can be widely applied not only to ordinary conduits but also to pipes, shaft sections in buildings, shaft passages, and other installation routes where similar problems are likely to occur.

[Means for Solving the Problems] The present invention focuses on the fact that the above-mentioned problems will not occur if the end portion of the cable to be laid has sufficient bending flexibility and appropriate rigidity. A cable traction section is constructed by adding a filament body that has the same features as the tip of the cable.

That is, the cable traction section of the present invention is formed by intervening and connecting a metal concentric stranded wire of a required length between the cable end, which is exposed by removing the covering of the cable to be laid, and the traction tool. It is characterized by being something.

[Function] Since the bending rigidity of the metal concentric strands interposed and connected between the tip of the co-cable and the traction tool is smaller than that of the cable, it easily follows the traction rope and guides the following cable without difficulty. The tip of the cable has a narrow step,
Easily passes through bends, etc.

[Example] An example of a cable traction section according to the present invention will be described with reference to the drawings. In the figure, 1 is a cable with high bending rigidity to be installed, for example, a 77kV single-core 6
00mm2 cross-linked polyethylene insulated vinyl sheathed cable. 2 is a conductor of the cable 1 made of twisted copper wires; 3 is a coating layer of the cable 1 including a coating made of highly rigid cross-linked polyethylene. Reference numeral 4 denotes a metal concentric stranded wire connected to the cable 1, and in this embodiment, the cross-sectional area of concentrically twisted annealed copper wire is 200 m.
Ordinary vinyl insulated wires, vinyl insulated vinyl sheathed cables, etc. (hereinafter referred to as "flexible cables") having a soft polyvinyl chloride coating layer 6 on a conductor 5 of m2 or 325 mm2 are used.

In this way, when the metal concentric stranded wire 4 is a concentric stranded wire made of the same material as the cable 1 to be laid, it is desirable to use a wire whose cross section is smaller than that of the cable 1 to be laid.

In addition, if the metal concentric stranded wire 4 is a coated conductor, the coated layer should be made of a material more flexible than that of the cable 1, as in the flexible cable of this embodiment. It is desirable that the coating material be the same, and the coating needs to be thin enough not to affect the bendability required of the metal concentric strands 4.

Incidentally, the metal concentric stranded wire 4 is located between the cable 1 and the traction tool 9 and serves as a guide to guide the cable 1 without difficulty. It has bending adaptability and appropriate bending rigidity to easily follow the conditions, and has ease of connection to obtain a rigid interposed connection with the cable 1, so it is all necessary for the metal concentric stranded wire 4. It satisfies the characteristics of

The metal concentric stranded wire 4 has a structure in which one to several strands are twisted concentrically in alternating opposite directions, and there are various drawbacks of clustered stranded wires, composite stranded wires, etc. For example, a thin composite stranded wire has sufficient flexibility but lacks adequate bending rigidity, so there are no drawbacks such as rendering it unusable.

The length of the metal concentric stranded wire 4 is determined by considering the outer diameter of the cable 1 to be laid, the conditions of the laying route, economic efficiency, etc., but it is recommended that the length be at least 50 cm for laying high voltage cables. In this example, the length is approximately 2 m in order to obtain sufficient bending flexibility.
It's Nishide.

Incidentally, the metal concentric stranded wire 4 is not necessarily limited to a cable having a soft coating on an annealed copper stranded wire conductor as in this embodiment, but may be, for example, a high tensile strength concentric bare stranded wire made of a different material. etc. may be used.

Reference numeral 7 denotes a connecting portion between the conductor 2 of the cable 1 and the conductor 5 of the flexible cable 4, which is made to have a load capacity of approximately 1 ton by inserting both conductors into a sleeve and compressing them.
The means for forming such a connection is the metal concentric strand 4 used.
Connection methods other than compression connection may be used depending on the characteristics of the connection.

8 is a flexible cable made from the covering layer 3 of the cable 1;

This is a valley-filling layer formed over the coating layer 6 of No. 4, and is formed so that the outer diameter becomes smaller in the direction of the tip. The valley filling layer 8 fills the difference in outer diameter between the cable 1 and the flexible cable 4 and
Although the purpose of preventing the cable 1 from getting caught on steps, etc., and the purpose of making the cable 1 waterproof and dustproof (if applicable), these are not necessarily indispensable for implementing the present invention.For example, the flexible If there is no large difference between the cross-sectional size of cable 4 and that of cable 1, and it is sufficient to simply consider waterproofing, dustproofing, etc., use cable 1.
It is also sufficient to cover only the vicinity of the ends. Note that the valley filling layer 8 of this embodiment is formed by tape processing.

When laying the cable 1 using the cable traction section of the present invention configured as described above, the traction rope is connected to the traction tool 9 and hoisted with a winch, etc., as in the case of ordinary cable installation. However, the cable is guided by concentric stranded metal wires that have small bending rigidity from bending to pulling, so it can be easily pulled even when there are small bends in the radius, narrow steps, etc. do.

Therefore, there are no cases in which the cable cannot be laid due to the tip of the cable getting caught in a narrow part, a stepped part, etc. in the laying route.

Furthermore, when the cable pulling section of the present invention is used, there is a great economical advantage because only the metal concentric strands need to be removed after installation.

[Effects of the Invention] As described above, the cable pulling section according to the present invention is of MA construction in which the metal concentric stranded wire having low bending rigidity near the cable is interposed and connected between the cable to be laid and the pulling tool. Therefore, the cable can be easily laid using the metal concentric strands as a guide even in a laying route with many bends, steps, narrow areas, etc., and the industrial value is extremely high.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram showing an embodiment of a cable traction section according to the present invention, and Figs. 2 and 3 are diagrams showing a case where a cable is laid in a conduit using conventional technology. FIG. 3 is a diagram showing the state of a cable tip that goes down to a stepped portion, a bent portion, etc.; 1 Niblast cable, 2: Conductor, 3: Covering layer, 4: Flexible cable, 5: Conductor, 〇Two-liquid coating layer, 7: Connection part, 8: Valley filling layer, 9: Pulling layer. Fastener, 10: Pipe, 11: Rope, 12: Step part, 14: Bent part.

Claims (2)

[Claims] (1) A metal concentric stranded wire having a lower bending rigidity than that of the covered cable is installed between the exposed conductor end portion of the sheathed cable having a high bending rigidity and the traction device to be connected thereto. A traction section of a sheathed cable, characterized by an intervening connection. (2) The covered cable according to claim 1, wherein the covered cable with high bending rigidity is a high voltage cross-linked polyethylene insulated cable, and the metal concentric stranded wire with low bending rigidity is a vinyl insulated wire or cable. traction part.