JPH10169885A - Method for protecting cable, and protective pipe for cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the connection structure of a protective pipe, and to facilitate the handling by fitting the protective pipe provided with a female screw part on one end side and a male screw part on the other end part into a cable at each end part in the longitudinal direction of a synthetic resin cylindrical body, and screwing the protective pipes adjacent to each other at the male and female screw parts. SOLUTION: In a synthetic resin protective pipe 1 for a cable to be used for the cable to be embedded in a concrete skeleton of a prestressed structure, a female screw part 2 is integratedly provided on one end in its longitudinal direction, and a male screw part 3 to be screwed to the female screw part 2 is integratedly provided on the other end part. An elastic ring 4 consisting of rubber as a sealing means is fitted to a rear part of the male screw part in an attachable/detachable manner. During the screwing in which the cable is covered by continuously arranging the protective pipes 1 adjacent to each other by screwing the male and female screw parts 2, 3, an outer circumferential surface of the elastic ring 4 is abutted on a tip part of the female screw part 2 accompanied by the deformation caused by the pressing force, and the liquid such as rain is prevented from entering inside the protective pipe l.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to, for example, post-tension type tension cables and other general cables among tension cables (inner cables) buried and disposed in a concrete body of a prestressed (PC) structure. The present invention relates to a cable protection tube to be used and a cable protection method.

[0002]

2. Description of the Related Art Conventionally, in a post-tension type PC cable of an inner cable, a steel protective tube having a spiral or corrugated shape is previously installed in a form together with a reinforcing bar of a general rebar, and is struck into the form. After the installed concrete is hardened, the steel material for prestress included (PC steel material)
Is generally tightened between fixing tools provided at both ends of the protective tube, and then cement grout or cement milk is injected into a gap between the protective tube and the PC steel material.

On the other hand, in recent years, there has been an increase in the number of PRC structures permitting the generation of cracks within a prescribed range in marine structures and concrete using prestress technology, or structures in a chemical reaction environment in heavy chemical regions.
In order to block any rust accelerating substances that enter the structure, a protective tube made of synthetic resin is increasingly used in place of the conventional steel protective tube.

[0004] In addition to the synthetic resin protective tube, for example, friction with the protective tube generated when the PC steel material contained therein is tensioned is greatly reduced as compared with a steel tube, and future maintenance is required. From the viewpoint of cost reduction, etc., considerable results have been achieved including foreign countries.

[0005] These synthetic resin protective tubes are transported to the site with a length of at most about 6 m due to restrictions on transportation and workability at the site, and these are connected to a long cable for connection. If this connection is made to be a completely sealed structure, an anticorrosion cable protected by a synthetic resin over its entire length can be constructed.

[0006] If this is realized, it is not only a complete anticorrosion cable that protects the PC steel material from the outside air, but also prevents a stray current, which causes electric corrosion, from entering the cable, and also fixes both ends of the cable from the viewpoint of maintenance. By insulating the components, an insulated cable over the entire length can be constructed.

In the future, the soundness of the protection tube can be verified only by periodically checking the electric resistance, and the maintenance cost can be greatly reduced. Normally, cement grout is injected into the gap between the sheathing protective tube and the PC steel material, but a very high-grade corrosion-resistant cable can be realized by the alkaline property and the completely sealed protective tube.

[0008]

However, in order to realize a high-grade corrosion-resistant cable at low cost and without increasing the complexity of the construction site, it is necessary to improve the structure of the portion connecting the protective tubes made of synthetic resin. There is a problem that there is.
Thus, the conventional synthetic resin protection tube has problems to be solved in terms of manufacturing cost and ease of handling.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the object of the cable protecting method according to the present invention, the object of the present invention is to provide a cable made of synthetic resin having two ends in the longitudinal direction. A cable protection tube provided with a female screw portion on the side and a male screw portion screwed to the female screw portion on the other end side and provided with a sealing means is fitted to the cable, and the cables adjacent to each other are connected. This is a method of covering the cable by screwing the male / female threaded portion of the protective tube into a successful connection.

The gist of the cable protecting tube according to the present invention is that a female thread is provided at one end of the cylindrical member made of synthetic resin at one end and the female screw is provided at the other end. A male screw part to be screwed into the screw part is provided and sealing means is provided, and the sealing means is one or more elastic rings fitted to the surface of the cylindrical body. It is.

According to the method for protecting a cable according to the present invention, a male / female screw portion as a connecting means is integrally provided on a cylindrical body made of a synthetic resin, and a cable protecting tube further provided with a sealing means is used. Thus, the covering operation of the cable is simple, and the sealing operation can be performed only by screwing.

According to the cable protection tube according to the present invention,
Since the male and female threads as connection means can be formed integrally with the cylindrical body, no extra parts such as special sheath joints or connection couplers are required for their connection, making it an economical and completely sealed protective pipe joint. The structure can be realized. The work of sealing connection is good only by screwing in manually.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a cable protection tube and a cable protection method according to an embodiment of the present invention. As shown in FIG. 1, the cable protection tube 1 is made of a synthetic resin such as polyethylene or polypropylene, and has a total length of about 4 m to 6 m and a diameter of about 35 mm to
It is a cylindrical protective tube 1a of about 120 mm, and a female screw 2 is integrally provided at one end in the longitudinal direction.

On the other hand, at the other end of the cylindrical protective tube 1a, a male screw portion 3 screwed to the female screw portion 2 is provided.
It is provided integrally.

Further, an elastic ring 4 made of rubber as sealing means is detachably fitted to the rear part of the male screw portion 3. The cross-sectional shape of the elastic ring 4 is not limited to a round shape but may be a rectangle or a trapezoid.

Further, a plurality of elastic rings 4 may be arranged side by side in order to achieve a tighter sealing structure. FIG. 2 shows a connection structure of the cable protection tube 1 of the present invention using one elastic ring 4.

As shown in FIG. 2, the mounting position of the elastic ring 4 is determined when the male thread 3 of the cable protection tube 1c is screwed to the female thread 2 of the adjacent cable protection tube 1b. The outer peripheral surface of the elastic ring 4 abuts on the distal end of the female screw portion 2 with deformation due to the pressing force, and is provided at a position where liquid such as rainwater does not enter the inside of the protective tube. Furthermore, in order to obtain a high sealing structure, it is also proposed to provide a heat-shrinkable tube on a resin coating in addition to increasing the number of elastic rings 4.

Since the elastic ring 4 is tightened by the female screw 2 by screwing the female screw 2 and the male screw 3, it is not always necessary to bond the elastic ring 4 to the protective tube 1a via bonding means. It also includes a method of detachably fitting, such as attaching to the protective tube 1a by the elastic force of the elastic ring itself.

The method of using the protective tube 1 for a cable thus formed will be described. As shown in FIG. 3, after the protective tubes 1b and 1c are connected and installed inside a concrete frame, a PC steel material is used. 5 is inserted later, and the fixing members provided at both ends are tightened by jacks. Thereafter, the cement grout 6 is injected to form a composite cross section in which the outer concrete skeleton, the protective tubes 1b and 1c, and the PC steel 5 are integrated.

[0020]

As described above, according to the method for protecting a cable according to the present invention, at both ends in the longitudinal direction of a synthetic resin tubular body, a female screw is provided at one end and the other end is provided. A cable protection tube provided with a male screw portion screwed to the female screw portion and provided with a sealing means is fitted to the cable, and the adjacent cable protection tubes are screwed into the female and male screw portions. In this method, the cable is hermetically covered by a successful connection, so that the economical connecting means is integrated into the cylindrical body to reduce the weight, and the connecting structure of the protective tube is simplified, which facilitates handling. Become.

In the cable protection tube according to the present invention, a female screw portion is provided at one end of a cylindrical member made of synthetic resin at one longitudinal end, and the female screw portion is screwed at the other end. With the provision of the male screw portion and the sealing means, the manufacturing cost of the protective tube is reduced by the connection structure, the number of parts is reduced, and not only the parts management becomes easy, but also the continuous sealing structure. This has an excellent effect that the work of the mold becomes easy.

[Brief description of the drawings]

FIG. 1 is a front view of a cable protection tube according to the present invention.

FIG. 2 is a partial cross-sectional view showing a state in which the cable protection tube according to the present invention has been successfully connected.

FIG. 3 is a cross-sectional view illustrating a use state of the cable protection tube according to the present invention.

[Explanation of symbols]

1 Cable protection tube, 2 female thread, 3 male thread,
4 Elastic ring, 5 PC steel, 6 cement grout.

Claims (3)

[Claims] At both ends in the longitudinal direction of a synthetic resin tubular body, a female screw portion is provided at one end thereof, and a male screw portion to be screwed to the female screw portion is provided at the other end thereof. Covering the cable by fitting a cable protection tube provided with a sealing means to the cable, and connecting the cable protection tubes adjacent to each other with each other by screwing the female and male threads to each other. To protect cables. 2. At both ends in the longitudinal direction of the synthetic resin tubular body, a female screw portion is provided at one end thereof, and a male screw portion to be screwed to the female screw portion is provided at the other end thereof. A protective tube for a cable, comprising sealing means. 3. The cable protection tube according to claim 1, wherein the sealing means is one or a plurality of elastic rings fitted on the surface of the tubular body.