JPS6338080Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a welding jig for welding multiple elongated materials along the longitudinal direction into an integrated elongated product, and particularly for canceling out welding distortion. The present invention relates to a welding jig that holds a long material in a reversely warped state.

Background of the invention The side rail 2 in the ladder frame structure of an automobile (mainly a truck) is, for example, shown in Figs.
As shown in FIG. 3, a structure with a box-shaped cross section is often formed by welding. It is made by fitting an inner rail 6, which is narrower in width, into the inner side of an outer rail 4 having a U-shaped cross section, facing each other, and then welding the fitted portions of the two along the longitudinal direction.

However, during welding, considerable distortion occurs in the direction shown by the two-dot chain line in Figure 2, so a welding jig is used to create a reverse warp in advance to cancel out the welding distortion, as shown by the broken line in Figure 2. It is desirable to perform welding in this condition. That is, three or more fixed clamps are arranged along the longitudinal direction of the combination of the outer rail 4 and the inner rail 6 (hereinafter referred to as a long work), and in collaboration with each of these fixed clamps, A movable clamping tool is provided that clamps the long workpiece from both sides, and three or more sets of clamp units clamp the long workpiece at three or more locations separated in the longitudinal direction, thereby canceling out welding distortion of the long workpiece. It is held in a reversely warped state, and welding is performed using a welding torch 8 or the like in this state.

However, since the appropriate amount of reverse warpage L ₁ , L ₂ to immediately cancel the welding strains l ₁ , l ₂ varies slightly depending on the length and shape of the side rail, the same welding jig may be used. When welding long workpieces with different lengths, it is extremely difficult to provide an appropriate amount of reverse warpage according to the lengths. Therefore, variations in the dimensional accuracy of the resulting welded products increase, and if the required dimensional accuracy cannot be obtained, it becomes necessary to correct the welding distortion using a hydraulic press or the like in a post-welding process.

This kind of thing does not only occur when the side rails of an automobile frame are made by welding, but generally when multiple long materials are welded along the longitudinal direction to form a single long product. The same can be said in any case.

Purpose of the invention The present invention was developed against this background, and its purpose is to hold a long material to be welded in a reversely warped state to cancel out the welding distortion. An object of the present invention is to provide a welding jig that can easily and quickly adjust the amount of reverse warpage, and can easily cope with changes in the length of a long material. .

Structure of the invention In order to achieve such an object, the present invention has three parts arranged along the longitudinal direction of a long material as described above.
In a welding jig equipped with three or more clamp units including three or more fixed clamps and a movable clamp that works together with the fixed clamps to sandwich a long material from both sides, at least one of the fixed clamps and at least two of the elongated materials are supported on separate bases, and at least one of the bases is positioned at a position offset in the longitudinal direction of the elongated material from at least one of the fixed clamps supported by the base. , attached to the main body of the device so as to be rotatable around a rotation axis perpendicular to the longitudinal direction thereof and the moving direction of the movable clamp, and at least one of the fixed clamps on the movable base. a rotational direction position adjustment device that allows the movable base to move in the longitudinal direction of the elongated material and adjusts the position of the movable base in the rotational direction;
and a longitudinal position adjustment device for adjusting the longitudinal position of the movable fixed clamp of the elongated material, so that the rotation of the movable base is adjusted as the position of the movable fixed clamp is changed. The gist is that the amount of reverse warpage can be changed by changing the moving position.

When there is only one fixed clamp supported by the movable base, in order to make the fixed clamp move in a direction perpendicular to the longitudinal direction of the long material as the movable base rotates. However, it is necessary to attach the movable base to the main body of the device so that it can rotate at a position that is removed from the fixed clamp.
If there are two or more fixed clamps supported by the movable base, even if the movable base is rotatably attached to the device body in a position away from any of the two or more fixed clamps, the movable base will not be fixed. It may be attached at a position corresponding to one of the clamps.

In short, a straight line connecting any two of the at least two fixed clamps supported on one side of the separate base (if there are three or more fixed clamps, the line connecting them is a straight line) the distance from the at least one fixed clamp supported by the other base changes as the movable base, which is one of the separate bases, rotates. It's okay.

Effect of the invention By doing this, the movable fixed clamp tool can be moved in the longitudinal direction of the long material to be welded according to the length of the long material to be welded, and its position can be adjusted. At the same time, by adjusting the position in the rotating direction of the movable base that supports the fixed clamp, the position of the fixed clamp can be adjusted both in the direction in which the long material should be warped and in the longitudinal direction of the long material. It is possible to easily change the appropriate amount of reverse warpage to be given to the long material, thereby making it possible to obtain welded products with high dimensional accuracy regardless of welding distortion. It becomes.

Embodiment Hereinafter, an embodiment in which the present invention is applied to a welding jig for truck frame welding will be described in detail with reference to the drawings.

In FIG. 4, 10 is a bed. Above the bed 10 are fixed clamps 2 supported by bases 12, 14, 16 and 18, respectively.
A total of nine numbers 0, 22, 24, and 26 are arranged. As shown in FIGS. 1 to 3, these fixing clamps are attached to a longitudinal outer rail 4.
It is a material that supports the long work W including the inner rail 6 and the inner rail 6 from below, and is arranged at approximately equal intervals along the longitudinal direction of the long work W to be welded.
In addition, in order to give the work W a reverse warp along the reverse warp curve that is estimated to be optimal for canceling the welding distortion, the positions in the vertical direction of each workpiece are determined in advance, and the lower surface (outer rail 4) of the long work W is Each is held in a position that allows surface contact. In addition, in FIG. 4, the long workpiece W is simply shown as having a simple straight line shape.

On the other hand, a total of nine movable clamps 28 are provided facing each of the fixed clamps 20 to 26, and although none of them are shown in FIG. The movable clamps 28 are respectively connected to and separated from the fixed clamps 20 to 26 by the operation of the clamp cylinders. and,
One of the movable clamps 28 that is raised and lowered by a clamp cylinder and the fixed clamps 20 to 26
A set of mutually opposing units constitutes a clamp unit, and in this embodiment, nine sets of clamp units are provided to clamp the long workpiece W at nine locations separated in the longitudinal direction. It is being done.

In addition, the above-mentioned fixed clamp tools 20 to 26
As shown in FIG. 5, all of the clamp units work together with the movable clamping tool 28 to clamp the workpiece W in a direction perpendicular to the direction in which the long workpiece W is clamped, or in other words, a side clamp unit. We are prepared. In this side clamp unit, a pair of clamp arms 32, 32 each having working portions facing each other in the width direction of a long workpiece W are attached to a fixed clamping tool 20 via pins 34, 34 to clamp the workpiece W.
The side clamp cylinder 36 is rotatably supported in a plane substantially perpendicular to the longitudinal direction of the clamp arms 32, and a side clamp cylinder 36 is provided between the ends of the clamp arms 32, 32 on the side opposite to the above-mentioned working part. . If the action parts of the clamp arms 32 are brought closer to each other by the operation of this cylinder 36, the long workpiece W shown in FIG. It can be made to disappear.

Among the nine fixed clamps, the central fixed clamp 22 is supported by a base 14, which is a fixed base fixed to the bed 10. On the other hand, the bases 1 and 16 located on both sides of the fixed base 14 have four fixed clamps 20 and three fixed clamps 24.
are supported in a fixed position, and these are considered to be the first movable base. That is, the movable bases 12 and 16 each have a movable clamp 2 at each end near the fixed base 14.
8 and the longitudinal direction of the long workpiece W, and is attached to the fixed base 14 by an axis 38 perpendicular to the moving direction of the movable clamp tool 28 and the longitudinal direction of the long workpiece W, within a plane (vertical plane in this case) parallel to the moving direction of the movable clamp tool 28, They are each rotatably supported around their respective axes.

Between the movable base 12 and the bed 10,
A fixing device 40 is provided for fixing the movable base 12 at a plurality of rotational positions. This part is enlarged and shown in FIG.

At the free end and middle part of the movable base 12,
While the brackets 42 are each fixed,
Stopper bolts 44 for adjusting the rotational position of the movable base 12 are screwed into the screw holes formed in these brackets 42 so as to protrude toward the bed 10, and are fixed by lock nuts 46. The rotational position of the movable base 12 is defined by the head of the movable base 12 coming into contact with the upper surface of the bed 10. Further, brackets 48 are fixed to the upper surface of the bed 10 on both sides of the movable base 12, and clamp bolts 52, 52 are tightened to the sides of the movable base 12 through elongated holes 50, 50 formed in these brackets 48. The stopper bolt 44 is
The head of the bed 10 is kept from separating from the upper surface of the bed 10. And those clamp bolts 52
By rotating the stopper bolt 44 with the lock nut 46 loosened, the movable base 12 can be rotated within a small angle range.

Furthermore, as shown in FIG. 4, a fixing device 4 is provided between the movable base 16 and the bed 10 on the opposite side to fix the movable base 16 at a desired rotational position in exactly the same manner. There is.

The fixed clamp tools 20 and 24 supported by the movable bases 12 and 16 as described above and the fixed clamp tool 22 supported by the fixed base 14 are used to hold a long workpiece while the movable bases 12 and 16 are in a straight line. Since the vertical positions of the movable bases 12 and 16 are determined in advance in order to give the W a reverse warp along the reverse warp curve estimated to be optimal for canceling welding distortion, the rotation of the movable bases 12 and 16 in a small angle range is possible. Due to the movement, the amount of reverse warp given to the long workpiece W in a state approximating the estimated reverse warp curve will be changed.

The base 18, which is located adjacent to the movable base 16 and supports the outermost stationary clamp 26, is a second movable base. That is, the end of the movable base 18 on the side of the movable base 16 is connected to the movable base 1.
6 by a shaft 54 parallel to the shaft 38, and is rotatable about the axis of the shaft 54 in substantially the same plane as the rotatable plane of the movable base 16. It is. Furthermore, the fixed clamp tool 26 is movable in the longitudinal direction of the long work W with respect to the movable base 18. The details of portion A including such second movable base 18 are shown in an enlarged scale in FIG.

As is clear from FIG. 7, a guide rail 56 is integrally provided on the upper surface of the second movable base 18, and a movable table 5 as a moving member is slidably disposed on this guide rail 56. A fixed clamp tool 26 is fixedly installed on the upper surface thereof. That is, the fixed clamp 26 is supported by the movable base 18 in a state where it can be moved in the longitudinal direction of the long workpiece W via the movable table 58, and the movable base 18 is supported by the movable base 16.
It is attached via a fixed base 14 to the main body of the apparatus consisting of the bed 10 and the main body frame 30. A longitudinal position adjustment cylinder 60 attached to the movable base 18 is connected to the movable table 58 . This cylinder 60 is
The fixed clamp tool 26 is moved via the moving table 58 in, for example, three steps within a range away from the axis 54 in the longitudinal direction of the long workpiece W, depending on the length of the long workpiece W to be welded. This constitutes a device for adjusting the longitudinal position of the fixed clamp 26, and the position of the fixed clamp 26 adjusted by the cylinder 60 is determined by a limit switch (not shown). ing.

Further, on the bed 10, two sliders 62, 62 which are integrally connected to each other are provided so as to be slidable in the longitudinal direction of the long work W. Two stoppers 64 and 66 are provided on the upper surface of these sliders 62, respectively, and project toward the lower surface of the movable base 18 at different heights. That is, these stoppers 64, 66 are
From the bottom surface of the movable base 18 to each stopper surface 68, 7
They are formed so that the distance to 0 is different in two steps and are spaced apart by a constant distance in the longitudinal direction of the workpiece W. Further, the top surface of the slider 62 is the lowest stopper surface, and as a result, three stoppers having three different heights are provided.

On the other hand, stopper contact portions 7 protrude from the lower surface of the movable base 18 toward each slider 62.
2 and 72 are provided, respectively. These stopper contact portions 72 are formed by members fixed to the movable base 18 in the shape of short shafts, and are configured to selectively contact the stopper surfaces 68, 70 of the respective stoppers 64, 66. has been done.

One slider 62 has a rotational direction position adjustment cylinder 74 fixed to the bed 10.
are connected, and the stopper contact parts 72, 72 on the movable base 18 side are connected to the stopper 6 on the slider 62 side.
Both sliders 62 are moved integrally to a position where they can abut either the slider 4 or 66 or the top surface of the slider. In addition, movable base 1
A lifting cylinder 78 is provided between the bed 10 and a bracket 76 fixed to the free end of the slider 8, and when the cylinder 74 slides each slider 62, the stopper abutting portion 72 is lifted up by the stopper 64,
It serves to temporarily lift the movable base 18 to a position where it does not interfere with the movable base 66.

In this embodiment, the sliders 62, 6 as described above are used.
2, stoppers 64, 66, stopper contact portion 72,
72, the rotation direction position adjustment cylinder 74, and the lifting cylinder 78 constitute a position adjustment device that adjusts the position of the movable base 18 in the rotation direction.

The above-mentioned movable clamp 28 is provided opposite the fixed clamp 26 of the movable base 18, and this movable clamp 28 is attached to a clamp cylinder 82 fixed to the main body frame 30 via a bracket 80. A piston rod 84 is attached to the tip of the piston rod 84 by a pin 86 so as to be rotatable around an axis perpendicular to the longitudinal direction of the long workpiece W, and the vertical movement of the piston rod 84 is guided by a guide rod 88. It's getting old.

By the way, the above-mentioned longitudinal position adjustment cylinder 6
0, a long workpiece W to be welded to each of the rotation direction position adjustment cylinder 74 and the lifting cylinder 78.
A control device including a sequence circuit is provided to operate the device in a predetermined order based on a single signal indicating the type of the device. The cylinders 60, 74, and 78 are operated in conjunction with each other by this control device, and the moving table 58 and sliders 62, 62 are moved to respective positions corresponding to the type of long workpiece W designated by the above signal. However, the specific configuration of the sequence circuit will be made clear in the explanation of the operation to be described later.

Next, a method of using the welding jig constructed as above will be explained.

When the work W to be welded is supplied to this welding jig, all the movable clamps 28 are held at the rising end position, and in this state, each fixed clamp 28 is
0, 22, 24 and 26 and each movable clamp tool 2
A long workpiece W is supplied between the workpiece 8 and the workpiece 8. Outer rail 4 and inner rail 6 that constitute this work W
This means that tack welding is performed in advance at a suitable number of locations in the longitudinal direction to maintain integrity. Also, a movable base 12 that supports the fixed clamp tool 20 and a movable base 16 that supports the fixed clamp tool 24.
However, in order to give the workpiece W the amount of reverse warpage that is estimated to be optimal, the rotation position is selected by the stopper bolt 44 shown in FIG.
is fixed in that position. Furthermore, regarding the second movable base 18 that supports the outermost fixed clamp tool 26, the position of the fixed clamp tool 26 in the longitudinal direction of the workpiece W is adjusted via the moving table 58 shown in FIG. Corresponding to the position in the longitudinal direction of the fixed clamp tool 26, by selecting an optimal position according to the length and abutting each stopper contact portion 72 with the stopper 64, 66 or the top surface of the slider, The rotational position of the movable base 18 is in a predetermined state to provide an appropriate amount of reverse warpage.

Each movable clamp 28 is moved closer to the corresponding fixed clamp 20, 22, 24, 26, and the workpiece W is sandwiched between the movable clamps 28 and the fixed clamps, thereby reducing welding distortion of the workpiece W. Reverse warpage is given to counteract it. Furthermore, the workpiece W is clamped from the width direction by the side clamp unit included in each of the fixed clamps 20 to 26, and the gap between the outer rail 4 and the inner rail 6 in the width direction is eliminated.

In this way, the long work W is clamped from both the top and bottom directions and the width direction, and welding is performed along the welding line in the longitudinal direction of the work W while being reversely warped to form an integrated side rail. It is.

The above explanation is based on the case where a long workpiece W of a constant length is welded using this welding jig. When welding different workpieces (different workpieces), the length of the workpieces to be welded is determined by an appropriate type discrimination sensor before being supplied to the welding jig. It is determined,
A signal representing the determined type of workpiece is input to the control device. Based on this, the lifting cylinder 78 is first actuated to rotate the movable base 18 by a small angle around the axis of the shaft 54, lift it upward, and temporarily hold it in that position. Further, for example, if the workpiece W' to be welded next is longer than the workpiece W welded before, the cylinder 60 moves the fixed clamp 26 via the movable table 58 a distance l. to the free end side of the movable base 18, and position it at the optimal position in the longitudinal direction for giving reverse warp to the workpiece W'.
Further, the rotational direction position adjustment cylinder 74 is configured to adjust the rotation direction position adjustment cylinder 74 in accordance with the moving direction and amount of movement of the fixed clamp tool 26.
In order to properly correct the vertical position of the fixed clamp 26 in order to provide the above-mentioned reverse warpage, for example, the stopper abutting portion 72 can move beyond the stopper 64 from a position where it can abut against the stopper 70 as shown in FIG. Each slider 62 is advanced in the longitudinal direction of the workpiece W' to a position where it can contact the top surface of the slider 62, so that the stopper contact portion 72 can contact the top surface of the slider 62, which is the lowest stopper surface. . The end of movement of the slider 62 is detected by a limit switch, and based on a signal therefrom, the lifting cylinder 78 is lowered, so that
Each stopper contact portion 72 comes into contact with the upper surface of the slider 62, and the rotational position of the movable base 18 is corrected downward by the height of the stopper 70, and the fixed clamp 26 is lowered by that amount. It is.

In this state, the part near the end of the workpiece W' is sandwiched between the fixed clamp tool 26 and the movable clamp tool 28, and the other fixed clamp tool 20
24 and each movable clamp tool 28 to give a reverse warp to the workpiece W' as a whole, even if the workpiece W' is longer than the previous workpiece W,
Appropriate reverse warpage is provided to cancel out welding distortion, and a welded product with high dimensional accuracy can be obtained.

In other words, in order to hold a long type of workpiece W' in a reversely warped state, it is desirable to move the outermost fixing clamp 26 toward the end of the workpiece W'; In this case, an error occurs in the vertical position of the fixed clamp 26 by the amount of the shift (it becomes too high), and as a result, the amount of reverse warp that should be given is insufficient and the welding distortion cannot be completely offset. This results in variations in dimensional accuracy for each workpiece. On the other hand, if another workpiece shorter than the workpiece W is to be welded, the above will be reversed and the position of the fixed clamp tool 26 will become too low.

However, as in this embodiment, the fixed clamp tool 2
In other words, the rotational position of the movable base 18 is corrected in stages as the movable base 18 is moved in the longitudinal direction according to the type of long workpiece.
When the fixed clamp tool 26 is moved outward to accommodate a long workpiece, the rotational position of the movable base 18 is corrected downward, and when the fixed clamp tool 26 is moved inward to accommodate a short workpiece. for,
By correcting the rotational position of the movable base 18 upward, it is possible to easily deal with differences in the length of long workpieces, and it is possible to give each workpiece a reverse warpage that is estimated to be optimal. .

Note that the position of the movable clamp tool 28 corresponding to the fixed clamp tool 26 in the longitudinal direction of the workpiece does not change, so when the fixed clamp tool 26 is moved in the longitudinal direction, the workpiece cannot be held in a state where they are not completely opposed to each other. Although it will be pinched from both sides, it will not be in a state of extreme discrepancy, so there is no practical problem in giving an appropriate reverse warp.

In addition, when it becomes necessary to change the amount of reverse warpage to be applied to a long workpiece over the entire length direction due to changes in welding conditions, etc., the rotational position of each of the movable bases 12 and 16 may be changed. can be adjusted upward or downward. That is, the sixth
With the clamp bolt 52 shown in the figure loosened and the lock nut 46 loosened, the stopper bolt 44 is
After rotating the movable bases 12 and 16 to change the rotational position of the movable bases 12 and 16 so as to obtain the amount of reverse warpage estimated to be optimal, it is sufficient to hold the movable bases 12 and 16 in that position using the lock nut 46 and the clamp bolt 52. be.

Note that the fixed clamps 20 and 24 supported by the movable bases 12 and 16, respectively, are displaced along arcs centered on the axis of the shaft 38, but the rotation angle is small;
In addition, since their positions before changing their positions correspond to the reversely warped shape that is estimated to be optimal for a long workpiece as described above, the fixed clamping tool 20,
The new reverse warp shape provided by the displacement of 24 does not cause any errors that are of any practical significance.

In the embodiment described above, the longitudinal position adjusting cylinder 60 and the rotational position adjusting cylinder 7 are
A control device equipped with a sequence circuit was provided to operate the 4 and 4 in conjunction with each other.
When multiple types of workpieces to be welded are supplied in a predetermined order, it is possible to know in advance what type of workpieces will be supplied.
Based on the signal representing that information, the cylinder 6
It is also possible to operate 0, 74, etc.

Further, instead of providing the stoppers 64 and 66 on the slider 64, the stoppers 64 and 66 are provided on the lower surface of the movable base 18, and a stopper abutting portion that can alternatively abut against them is provided on the upper surface of the slider 62. Good too. On the other hand, in place of the slider 62 that is movable in the longitudinal direction of the workpiece, a disc-shaped rotating member that is rotatable around a single axis perpendicular to the longitudinal direction is provided, and the height is gradually increased around the circumference of the rotating member. It is also possible to provide a plurality of stoppers with different values, and to selectively abut the stopper abutting portions on the stoppers. Furthermore, instead of varying the height in stages, an inclined stopper surface may be formed to provide a stopper with continuously varying heights. When the slider 62 is provided with such an inclined stopper, the cylinder 74 that drives the slider 62 is
It is preferable to use an electric cylinder or the like with good stopping position accuracy.

In addition, the device for adjusting the rotational position of the movable base 18 is not limited to one that uses the stopper as described above, but also includes an adjustment bolt that can be screwed into and out of the movable base 18. It is also possible to screw these into a position-fixed member and connect the adjustment bolt to a motor or the like that rotates in both forward and reverse directions to function as a rotational direction position adjustment device. Alternatively, the rotational position of the movable base 18 can be adjusted by providing a servo cylinder between the movable base 18 and a fixed member such as the bed 10, and controlling the amount of fluid supplied to the cylinder using a servo valve or the like. It is also possible to configure it to do so. Alternatively, the rotation direction adjusting device may be constructed by preparing a plurality of spacer blocks having different thicknesses and interposing one of them between the movable base 18 and the bed 10 by appropriate attachment/detachment means. You can also do it.

Further, the movable clamping tool 28 corresponding to the position-adjustable fixed clamping tool 26 can be made to be able to change its position in accordance with the change in the position of the fixed clamping tool 26 in the longitudinal direction of the workpiece. Furthermore, a second movable base 18 is provided not only on one end side of the long work W to be welded but also on the other end side, and the fixed clamp tool located at the outermost side of the other side is connected to the fixed clamp tool 26. Similarly, the position may be adjustable.

Although not described in detail, it goes without saying that the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a side rail of a truck frame as an example of a long product, and Fig. 2 is a front view thereof, showing the normally occurring welding distortion and the reverse warp given to cancel the welding distortion. It is a figure explaining the form of. FIG. 3 is a - sectional view in FIG. 1. Fig. 4 is a simplified front view of the entire welding jig as an embodiment of the present invention, and Fig. 5 is a partial side view showing a part of the fixed clamp shown in Fig. 4. It is a diagram. FIG. 6 is a partial front view enlarging a part of FIG. 4 and showing it in more detail, and FIG. 7 is a partial front view showing A in FIG. 4.
FIG. 3 is a partial front view showing a portion enlarged and shown in more detail. 2: Side rail (long product), 4: Outer rail, (long material), 6: Inner rail, 12,1
6: First movable base, 14: Fixed base, 1
8: Second movable base, 20, 22, 24, 2
6: Fixed clamp tool, 28: Movable clamp tool, 3
8, 54: shaft, 40: fixing device, 58: moving table (moving member), 60: longitudinal position adjustment cylinder,
62: Slider, 64, 66: Stopper, 72:
Stopper contact portion, 74: Rotation direction position adjustment cylinder, 78: Lifting cylinder.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A jig for welding a plurality of elongated materials along the longitudinal direction into an integrated elongated product, which 3, comprising three or more fixed clamps arranged along the same line, and a movable clamp provided opposite each of the fixed clamps to clamp the elongated material from both sides in cooperation with each of the fixed clamps. A welding jig comprising at least a set of clamp units, clamping the elongated material at three or more locations spaced apart in the longitudinal direction, and holding the elongated material in a reversely warped state to cancel welding distortion. , at least one and at least two of the fixed clamps are supported on separate bases, and at least one of the bases is connected to the elongated material from at least one of the fixed clamps supported by the base. is attached to the main body of the device so as to be rotatable around a single rotation axis perpendicular to the longitudinal direction and the direction of movement of the movable clamp tool at a position separated from the longitudinal direction of the movable clamp tool, and serves as a movable base. a rotational direction position adjustment device that makes at least one of the fixed clamping tools movable in the longitudinal direction of the elongated material and adjusts the position of the movable base in the rotational direction; and the movable fixed clamping tool. and a longitudinal position adjustment device for adjusting the longitudinal position of the elongated material, and the rotating position of the movable base is changed in accordance with the change in the position of the movable fixed clamp tool. A welding jig for long products, characterized in that the amount of reverse warpage can be changed. (2) The movable fixed clamp is supported by the movable base via a movable member movable in the longitudinal direction of the elongated material, and a cylinder for driving the movable member is connected to the movable base. ,
The welding jig according to claim 1, wherein the cylinder constitutes the longitudinal position adjustment device. (3) The rotational direction position adjustment device is provided on a slider that is movable in the longitudinal direction of the elongated material, and on either the slider or the movable base at different heights. a plurality of stoppers; provided on the other of the movable base and the slider; selectively abutting on one of the plurality of stoppers and working with the stopper to stepwise define the rotational position of the movable base; a stopper abutting section for contacting the plurality of stoppers; and a driving device connected to the slider and driving the slider to a position where the stopper abutting section can abut any one of the plurality of stoppers. A welding jig according to claim 1 or 2 of the invention registration claim. (4) A change in the rotational position of the movable base in accordance with a change in the position of the movable fixed clamp implements the longitudinal position adjustment based on a single signal indicating the type of long material to be welded. The operation is carried out by a control device that operates the device and the rotational position adjustment device to move the fixed clamping device and the movable base to respective positions corresponding to the type of elongated material specified by the signal. A welding jig according to any one of claims 1 to 3 of the patent claims.