JPS601904Y2 - Jig for positioning welding torch inside double pipe - Google Patents

Description

[Detailed description of the invention] The present invention is based on the pipe end of the inner cylinder that becomes the welding groove when performing fillet circumference welding between the inside of the outer cylinder constituting a double pipe and the inner cylinder fitted into this outer cylinder. The present invention relates to a jig that can accurately position a welding torch with respect to a part.

When forming a double pipe by fitting a fitting pipe inside a small diameter pipe and TIG welding (inert gas tungsten arc welding) the end of the inner pipe, such a double pipe As shown in FIG. 1, which shows the welding work state, the tungsten electrode 3 of the welding torch 2 is provided at the tip of the rod-shaped torch body 1, and the tube end 6 of the inner tube 5 fitted into the outer tube 4. Welding torch 2 so that the
It is necessary to position the weld to prevent welding defects from occurring.
Generally, the length of the inner tube 5 fitted into the outer tube 4 is measured in advance, and the tungsten electrode 3 is positioned from the inlet end 7 of the tubes 4 and 5 to the tube end 6 of the inner tube 5. .

Therefore, when performing fillet circumference welding of a large number of such double pipes, if the length of the inner pipe 5 fitted into the outer pipe 4 is uneven, the time required for these measurements will increase. , there is a drawback that the welding operation time is significantly increased.

In addition, in order to ensure that minute cracks that occur in heat exchanger tubes, such as holes, are closed, the purpose is to reduce the gap between the heat exchanger tube and the repair tube that is inserted here. When expanding these pipes in advance, the length of the repair pipe tends to increase, making it difficult to accurately position the tungsten electrode of the welding torch with respect to the end of the repair pipe, making it difficult to weld. There is a risk of inducing defects.

The present invention eliminates such conventional drawbacks and, when performing fillet circumference welding between the outer cylinder constituting the double pipe and the inner cylinder fitted into the outer cylinder, the inner cylinder, which becomes the welding groove, is The purpose is to provide a jig that can accurately position a welding torch with respect to the pipe end, and the structure of the jig for positioning a welding torch in a double pipe according to the present invention, which is distantly related to this purpose, is as follows: A welding torch for performing fillet circumference welding between the inner circumferential wall of the outer cylinder and the pipe end of the inner cylinder is provided at the tip of a torch main body of a bar material inserted into the inner cylinder fitted inside, An annular positioning member is fixed to the distal end of the main body, and an end face that can be engaged with the pipe end of the inner cylinder is attached to the distal end of a plate-shaped arm extending from the positioning member, and a cylindrical aperture member has an end face fixed to the distal end of the plate-shaped arm extending from the positioning member. A claw portion is formed with an inclined surface that comes into contact with the drilled elongated opening, and when the aperture member is movably fitted into the torch body and these are moved relative to each other by a certain amount, the opening is closed. The claw portion protruding from the torch portion is pushed between the throttle member and the torch body against the elastic force of the arm portion so that they can move within the inner cylinder. be.

Hereinafter, an embodiment in which the jig for positioning a welding torch in a double pipe according to the present invention is applied to a TIG welding device will be described in detail with reference to FIGS. 2 to 4.

A rod-shaped torch main body 13 inserted into an inner cylinder 12 having an outer diameter approximately equal to the inner diameter of the outer cylinder 11 has a current-carrying part 15 connected to a tungsten electrode 14 and an insulating ceramic 16 surrounding them, etc. at the tip thereof. A TIG welding torch 17 is provided, and by rotating this TIG welding torch 17 together with the torch body 13 within the inner cylinder 12, the outer cylinder 1
The pipe end 18 of the inner cylinder 12 fitted into the inner cylinder 1 and the inner peripheral surface of the outer cylinder 11 are welded by fillet circumference.

An annular positioning member 19 is fixed to the tip of the torch body 13 connected to the TIG welding torch 17, as shown in FIG. 3, which shows the appearance of the positioning member and the aperture member. In the figure, in this embodiment, the three arm portions 20, which are plate-shaped as elastic members extending downward, have an end surface 22 that can be engaged with the pipe end surface 21 of the inner cylinder 12, and a throttle member to be described later. A claw portion 26 is formed at the distal end of each of the claws 23 and has an inclined surface 25 that contacts an elongated opening 24 formed at the tip of each of the claws 23 .

The outer diameter of this positioning member 19 needs to be smaller than the inner diameter of the inner cylinder 12, but the distance from the axis of the torch body 13 to the tip of the claw part 26 is longer than the inner radius of the inner cylinder 12, and the outer diameter of the outer cylinder Make it shorter than the inner radius of.

The cylindrical aperture member 23 has a structure in which the tip part accommodates the arm part 20 and claw part 26 of the positioning member 19, and is slidably fitted to the torch body 13. A groove 27 is cut into the upper end surface of the diaphragm member 23 that can come into contact with the lower end surface of the member 19, and the groove 27 is cut through the arm 20, and the opening 24 engages with the claw 26 to cause it to protrude.
are perforated in the side wall of the tip of the diaphragm member 23, respectively.

In the figure, the torch body 13 is provided with a diaphragm member 23 that can be moved by a constant amount of 1 with respect to the torch body 13.
A seat 28 is formed that can come into contact with the lower end surface of the diaphragm member 23, and a fixing screw 29 is attached to the diaphragm member 23 for fixing it to the torch body 13.

Note that when the lower end surface of the diaphragm member 23 is brought into contact with the seat 28 of the torch body 13 as shown in FIG.
is moved slightly downward from the claw portion 26, and the claw portion 26 resists the elastic force of the arm portion 20 and is pushed between the torch main body 13 and the diaphragm member 23, so that the torch The distance from the axis of the main body 13 to the tip of the claw part 26 is shorter than the inner radius of the inner cylinder 12, and these parts are connected to the inner cylinder 1.
It is possible to move freely within 2.

When positioning the TIG welding torch 17 inside the double pipe using the apparatus of this embodiment, the second
As shown in the figure and FIG. 4, first shift the throttle member 23 downward in the figure with respect to the torch body 13, and with the lower end surface of the throttle member 23 in contact with the seat 28 of the torch body 13, tighten the fixing screw. 29 to fix the diaphragm member 23 to the torch body 13.

As a result, the claw portion 26 protruding from the opening 24 of the diaphragm member 23 is pushed into the space between the torch body 13 and the diaphragm member 23, and the inner cylinder 1 is fitted into the outer cylinder 11.
2 (see FIG. 2).

After feeding the torch main body 13 into the inner cylinder 12 by a length longer than the cylinder length of the inner cylinder 12 so that the claw part 26 of the positioning member 19 completely passes through the inside of the inner cylinder 12, tighten the fixing screw 29 to remove the diaphragm member. When the diaphragm member 23 is lifted by a certain amount 11 relative to the torch body 13 until the upper end surface of the diaphragm member 23 comes into contact with the lower end surface of the positioning member 19, the opening 24 of the diaphragm member 23, which was located slightly below the claw portion 26, is opened. Because of the upward movement, the claw portion 26 returns to its original state of protruding from the opening 24 by the spring force of the arm portion 20 (see FIG. 4a).

Note that once the claw portion 26 has been fed into the inner cylinder 12, the fixing screw 29 may be loosened. Due to the spring force of the arm portion 20, the claw portion 26 expands together with the arm portion 20 to its original state, and as a result, the throttle member 23 is actually pulled upward relative to the torch body 13, so that even from the outside It is possible to easily confirm that the claw portion 26 has passed through the inner cylinder 12.

Thereafter, when the torch body 13 is lowered, the end surface 22 of the claw portion 26 of the positioning member 19 is locked to the tube end surface 21 of the inner cylinder 12, making it impossible to lower the torch body 13 any further (fourth (see figure).

At this time, from the tungsten electrode 14 to the end surface 22 of the claw portion 26,
The distance 12 to is always constant.

From this state, lift only the torch body 13 by a certain amount □ with respect to the diaphragm member 23 and bring the seat 28 of the torch body 13 into contact with the lower end surface of the diaphragm member 23 (see Fig. 4C), and then the claws 26 is pushed between the torch body 13 and the diaphragm member 23, and it becomes possible to move these together within the inner cylinder 12. The distance between 11 and t
! 2, by lowering the torch body 13 together with the throttle member 23 by L from this state, the tungsten electrode 14 and the tube end surface 21 of the tube 12 can be accurately opposed to each other (Fig. 4). (See C).

Next, the torch main body 13 is rotated to start TIG welding between the pipe end 18 of the inner cylinder 12 and the inner circumferential wall of the outer cylinder 11 that comes into contact with this, and a weld bead 30 is formed here. Once the main body 13 has rotated once and the welding work has been completed, the torch main body 13 can be pulled out from the inner cylinder 12 together with the diaphragm member 23 (see FIG. 4C).

As described above, according to the jig for positioning a welding torch inside a double pipe of the present invention, there is no need to measure the pipe length of the inner cylinder fitted into the outer cylinder, and the torch body can be simply inserted into the inner cylinder and reciprocated. By moving the welding torch, it becomes possible to accurately position the welding torch at the tube end of the inner cylinder, and it is possible to prevent welding defects from occurring.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the state of welding a double pipe using a conventional method, Fig. 2 is a sectional view showing the structure of an embodiment of the present invention, and Fig. 3 is a sectional view showing the positioning member and the tip of the aperture member. Figures 4a and 4e are sectional views corresponding to the left half of Figure 2 showing the welding procedure. In the drawings, 11 is an outer cylinder, 12 is an inner cylinder, and 13 is an inner cylinder. Torch body,
14 is a tungsten electrode, 17 is a TIG welding torch, 1
8 is a tube end of the inner tube, 19 is a positioning member, 20 is an arm portion of the positioning member, 21 is a tube end surface of the inner tube, 22 is an end surface of a claw portion, 23 is a diaphragm member, 24 is an opening of the diaphragm member, 25 is an inclined surface of the claw portion, 26 is the claw portion of the positioning member, and 28 is a seat of the torch body.

Claims (1)

[Scope of utility model registration request] A welding torch for performing fillet circumference welding between the inner peripheral wall of the outer cylinder and the pipe end of the inner cylinder is provided at the tip of a rod-shaped torch main body inserted into the inner cylinder fitted into the outer cylinder, and the An annular positioning member is fixed to the tip of the torch body, and a plate-shaped arm extending from the positioning member has an end surface that can be engaged with the pipe end surface of the inner cylinder, and a cylindrical diaphragm member has a tip end. A claw portion is provided with an inclined surface that contacts the elongated hole-shaped opening, and when the aperture member is movably fitted into the torch body and these are moved relative to each other by a certain amount, the The claw portion protruding from the opening is pushed between the diaphragm member and the torch body against the elastic force of the arm portion, so that the claw portion can move within the inner cylinder. Jig for positioning the welding torch inside the pipe.