JP2778867B2 - Gas shield required for welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding gas shield tool which can easily and reliably secure a backside gas shield in butt welding of pipes in a short time.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional gas shielding means on the back surface of a welded portion in butt welding of pipes. At the time of gas shielding at the time of welding, a lid 10 having a small hole 11 formed therein is fitted into one end opening of a pipe 4 'to be butt-welded, and a small hole similarly formed is formed at the other end opening of the pipe 4'. A gas inlet pipe 2 'for supplying gas into the pipe is connected to the lid 10' having a lid 11 'and an argon gas is introduced from the gas inlet pipe 2' through a small hole 11 '. Then, the air in the pipe 4 'is replaced with argon gas to perform gas shielding on the back surface of the butt weld 5' of the pipe 4 '. At this time, the air in the pipe 4 'is released into the atmosphere through the small holes 11 opened.

[0003]

In the case of the above-mentioned conventional gas shielding means, it is necessary to flow argon gas through the entire pipe.

[0004] Therefore, it takes time to completely replace the air in the pipe with argon gas, and it is necessary to confirm that the air in the pipe has run out using an oxygen analyzer or the like, which is troublesome.

Further, a large amount of expensive argon gas must be used, which is not economical.

An object of the present invention is to provide a welding gas shield tool capable of solving the above-mentioned disadvantages of the prior art and reliably performing gas shielding on the back surface of the weld in a short time with a small amount of argon gas. It is an object.

[0007]

In order to achieve the above object, a welding gas shield tool of the present invention comprises a plurality of cylindrical gas blow-out pipes each having a gas introduction pipe connected to one end thereof and fixed to an annular outer peripheral wall thereof. The gas discharge pipe is provided with a small hole, and one end of a plurality of leaf springs is planted on both front and rear end faces of the gas discharge pipe, and the other end of the leaf spring is a free end.

[0008]

When the gas is shielded on the back surface of the weld at the time of butt welding of the pipe, the gas shield tool of the present invention is inserted into the pipe to be butt welded. By introducing argon gas from the gas inlet tube, the gas is blown out from the small hole provided in the annular outer peripheral wall of the gas outlet tube to the vicinity of the back surface of the welded portion, and the gas shields the pipe inner surface near the welded portion in a short time. .

At this time, the plurality of leaf springs, one ends of which are attached to the front and rear end surfaces of the gas blowing pipe, have their other free ends circumferentially in contact with the inner wall surface of the pipe, and the repulsive force of the spring moves the gas blowing pipe to the center position of the pipe. The gap between the inner surface of the pipe and the gas blowing pipe is kept constant.

By pulling the gas inlet pipe after welding, even if a weld back bead is present on the inner surface of the pipe, it can be easily pulled out of the pipe by utilizing the elasticity of the leaf spring.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a preferred embodiment of a welding gas shield according to the present invention.

In FIG. 1, reference numeral 1 denotes a gas blow-out pipe which can be inserted into a pipe 4, which is formed in a cylindrical body having a number of small holes 6 for gas blow-out on an outer peripheral annular wall, and one end of which is provided with argon gas A. A gas introduction pipe 2 for feeding is continuously provided.

A base of a plurality of leaf springs 3 is implanted and fixed to both end faces in the front-rear direction of the gas blowing pipe 1, and the other end of each leaf spring 3 is formed as a free end. These members constitute a welding gas shield tool.

In order to perform gas shielding on the back surface of the welded portion using the welding gas shield tool of the present invention having the above-described structure, as shown in FIG. 5 so that the gas blow-out pipe 1 is positioned on the back side.

In this state, one side of the gas
The free end of the other end of the leaf spring 3 to which the end is attached is in contact with the inner wall of the pipe, and the gas blowing pipe 1 is set at the center of the pipe by the repulsive force of the spring, so that the gap between the inner surface of the pipe 4 and the gas blowing pipe 1 is constant. Is kept.

During the butt welding of the pipe 4, the inner surface of the welded portion 5 is shielded by the argon gas A introduced from the gas inlet tube 2 and blown out from the small holes 6 of the gas outlet tube 1.

After the welding is completed, the gas shielding tool can be taken out of the pipe by pulling the gas introducing pipe 2 toward the outside of the pipe.

[0018]

As described above, according to the welding gas shield tool of the present invention, the gas shield of the welded portion on the inner surface of the pipe can be easily and reliably performed in a short time without using a large amount of expensive argon gas. You can do it.

Further, it is possible to omit the work of confirming whether or not the air in the pipe has been exhausted when replacing the air in the pipe with argon gas as in the prior art, which is efficient.

[Brief description of the drawings]

FIG. 1 is a sectional view of a welding gas shield tool according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a conventional gas shield means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas blowing pipe 2 Gas introduction pipe 3 Leaf spring 4 Pipe 5 Welded part 6 Small hole

Claims (1)

(57) [Claims] 1. A large number of gas blowing small holes are formed in an annular outer peripheral wall of a cylindrical gas blowing pipe having a gas introducing pipe communicated and fixed to one end, and a plurality of gas blowing small holes are provided on both front and rear end faces of the gas blowing pipe. A welding gas shield tool, wherein one end of a leaf spring is implanted, and the other end of the leaf spring is a free end.