JPH11210229A - Joining method of rod-like body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable joining of rod-like bodies such as shape different reinforcing bars at sufficient and uniform strength by covering the butted part of the rod- like bodies by a cylindrical mold, arranging the coil of a high frequency induction heater around the mold to be energized and removing the mold after pressurizing and cooling each rod-like body after fusion of the butted part. SOLUTION: One rod-like body 3 is fixed, the end is covered by a mold 1 whose inside diameter is slightly larger than the outside diameter of the rod-like body 3, the coil 2 of a high frequency induction heater is arranged therearound, and another rod-like body 3 is inserted in the mold 1 to be fixed. When heating temperature is set at the melting temperature of the rod-like body 3 or higher to energize the coil 2, the butted part of the rod-like bodies 3, 3 is melted. Thereafter, when each rod-like body 3, 3 is mutually pressurized, the space of the mold 1 is filled with the molten substance of each rod-like body 3, 3, and the part is slightly larger smooth than the outside diameter of the rod-like body 3 to be cooled so as to be integrated. Thereby strength of the joining part is very large and uniform, and shape different reinforcing bars different in size or the like can be joined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining rod-shaped members, such as deformed reinforcing bars, having a printed portion (bamboo joint) used for constructing a building such as a building or a bridge, in the longitudinal direction. .

[0002]

2. Description of the Related Art Conventionally, as a method of joining deformed reinforcing bars, there has been known a gas pressure welding method in which abutting portions of deformed reinforcing bars are pressed while being heated by a gas flame.

[0003]

The gas pressure welding method described above is very difficult to perform under rainy weather. In addition, since the worker performs the work manually, the finished strength and the like are not uniform, and the strength is often insufficient.

[0004] The present invention is to provide a sufficient and
It is an object of the present invention to be able to join rods such as deformed reinforcing bars with uniform strength.

[0005]

According to the method of joining rods of the present invention, the butted portions of the rods are covered with a cylindrical mold 1 having a constant inner diameter slightly larger than the outer diameter of the rods. The coil 2 of the high-frequency induction heating device is arranged around 1 and energized, and after the butted portions of the rods 3 and 3 are melted, the rods 3 and 3 are pressed against each other, and after cooling, the mold 1 is removed. Things.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, an embodiment of a method for joining rods according to the present invention will be described.

This joining method includes a mold 1 surrounding a butt portion of rods 3, 3 butting in a longitudinal direction, and a coil (commonly called a work coil) 2 for heating the butt portion. A high-frequency induction heating device and a hydraulic device 4 for pressing the rods 3, 3 together when the butting portion is melted are used. First, these will be described in order.

The mold 1 is made of wood ceramic. Its shape is a cylindrical shape with a constant inner diameter. It may be vertically divided into two members, in which case it is integrated with a fastening band or the like at the time of use, and is removed after joining the rods 3,3. Also, what is cylindrical from the beginning,
After the rods 3, 3 are joined, they are beaten and broken. The inner diameter of the mold 1 is slightly larger than the outer diameter of the rod.

The high-frequency induction heating device is a device for performing induction heating by inserting a metal object to be heated into the coil 2 connected to an alternating current. When an alternating current flows through the coil 2, an alternating magnetic flux is generated, which induces a very dense eddy current through the heated object. At that time, Joule heat is generated on the surface of the object to be heated. The high frequency induction heating device utilizes the heat. The coil 2 is a bare pipe-shaped copper wire, and cooling water for cooling the heating coil 2 at the time of heating is supplied to the hollow portion. Further, this high-frequency induction heating apparatus has a timer capable of setting the heating temperature to 1200 to 1600 ° C. and setting an energization time.

The hydraulic device 4 has a position fixing support 4a which can fix and release the rod 3 with a bolt 4c, and a rod 3 which can fix and release the rod 3 with a bolt 4d.
A movable support 4b which can be moved by hydraulic pressure is provided for the position fixed support 4a.

Next, a description will be given of a method of joining rods using the above-described tool or device.

First, one of the rods 3 is fixed to a position fixing support 4a of a hydraulic device 4 with bolts 4c, its end is covered with a mold 1, and a coil 2 of a high frequency induction heating device is arranged around the end. . Then, the other rod-shaped body 3 is inserted into the mold 1 and fixed to the moving support 4b of the hydraulic device 4 with bolts 4d and set. Next, when the heating temperature is set to be equal to or higher than the melting temperature of the rod (1600 ° C.) and the coil 2 is energized for several minutes (2 to 5 minutes depending on the thickness of the rod), the butted portions of the rods 3 and 3 Melts by raising the temperature to the set temperature (the melting temperature of the rebar is 1200 to 1400 °
C). Thereafter, the hydraulic device 4 is operated to move the movable support 4b, and the rods 3, 3 are pressed against each other. As a result, the melt 3 'of the rods 3, 3 is filled in the space of the mold 1 without gaps. Then, the portion becomes slightly larger and smoother than the outer diameter of the rod-shaped body 3, and is cooled and integrated. Finally, the mold 1 is removed to complete a series of operations. Since the tensile strength of the joint by this method is equal to or greater than that of the base material of the rod-shaped body 3, the joint does not break.

As shown in FIG. 2, if the joining method of the rod-shaped body is carried out using the mold 1 'whose central portion is bulged, it seems that a larger joining strength can be obtained. Is completely unexpected.

When the rod 3 is joined by the bulged mold 1 'at the center, the diameter of the fused joint becomes large, although the reason is not clear, but the joint changes from the original composition of the rod and becomes brittle. . Therefore, when bent, it breaks at the joint. In addition, when connecting reinforcing bars for building construction, since the connecting portion has a large diameter, if the reinforcing bars are densely arranged, the gap between the reinforcing bars decreases, and the flow of concrete deteriorates. Therefore, the joining portions of the adjacent reinforcing bars must be shifted from each other. Furthermore, since a change in the composition of the joint produces large irregularities on the outer surface, if it is exposed to rain before concrete is cast, rust is generated and deteriorates, and the durability after construction is reduced.

On the other hand, the mold 1 used in the present invention
Has a constant inner diameter slightly larger than the outer diameter of the rod-shaped body 3, so that the outer diameter of the joined portion is not much different from other portions, the composition does not change, and the outer surface is smooth. Therefore, the above-mentioned drawback does not occur when the rod-shaped body 3 is joined by the bulged mold 1 'at the center.

[0016]

Since the present invention is constructed as described above, it has the following effects.

That is, the strength of the joint is very large and constant. Also, it is possible to join deformed reinforcing bars having different thicknesses. Furthermore, since the work (heating) time is short and the mold used is inexpensive, it is economical and can be easily carried out anywhere with a power supply. In particular, since a cylindrical mold with a fixed inner diameter slightly larger than the outer diameter of the rod-shaped body is used, the outer diameter of the joint is not much different from the other parts, and the joint is larger than when using a mold with a bulged central part. Neither does the composition change of the part, does not break due to bending stress, and if the rod is a reinforcing bar for building construction, even if the reinforcing bars are densely arranged, it does not hinder the flow of concrete, and the adjacent joints Need not be shifted from one another. Furthermore, since the outer surface of the joint is smooth, there is little oxidative deterioration due to being left in the rain until the concrete is poured, and the durability after construction is increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a state in which a rod-shaped butting portion is set together with a mold and the like in a hydraulic device in carrying out a joining method of the present invention.

FIG. 2 is a vertical cross-sectional view of the vicinity of a butted portion of a rod-shaped body for explaining a joining method using a mold whose central portion is bulged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Heating coil of high frequency induction heating device 3 Rod

Claims (1)

[Claims] An abutting portion of a rod is covered with a cylindrical mold having a constant inner diameter slightly larger than the outer diameter of the rod, and a coil of a high-frequency induction heating device is arranged around the mold to energize the rod. A method of joining rods, wherein the rods are pressed together after the butt portion is melted, and the mold is removed after cooling.