JPH0444315Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention can be applied to expander type, portable type, and other spot welding machines to perform direct welding that can advantageously prevent the occurrence of dents on the workpiece. This relates to backbars for use.

(Prior Art) As a conventional welding back bar of this type, there is one shown in FIG. 4, for example.

The back bar 1 here has a thickness of 10 to 15 mm.
The back bar 1 is formed by processing the outer surface of a copper plate into a shape corresponding to the surface shape of the welded part of the workpiece, and the back bar 1 is placed in a predetermined position by a mounting bracket 2, preferably in the direction of its thickness. movably mounted.

For example, as shown in FIG. 5, when the back bar 1 is arranged along a required welding part Wp of the workpiece W, the backbar 1 and the backbar 1 move the welding part Wp of the workpiece W positioned at a predetermined position. Clamped with welding gun 3, and
By energizing the electrode tip 4, it functions to effectively prevent the occurrence of dents at the welding position.

(Problem to be solved by the invention) However, in this conventional technology, since the back bar 1 is made of a thick, or in other words, a highly rigid copper plate, it is particularly difficult to When the surface shape is a curved surface or other complicated shape, it is extremely difficult to form the copper plate surface into a shape that corresponds with the surface shape of the welding part Wp with sufficient accuracy by bending, grinding, etc. This is difficult, and there is a problem in that the number of man-hours required to form the surface increases significantly.

On the other hand, there is also the problem that it is virtually impossible to reshape the back bar 1 whose surface is formed for one type of workpiece W so that it can be applied to another type of workpiece. Ta.

This idea was made by focusing on the problems of the conventional technology, and it is possible to shape the surface of the back bar into a shape that corresponds to the surface shape of the welded part very easily, quickly, and with high precision. The present invention provides a back bar for direct welding that can be formed into a.

(Means for solving the problem) The back bar for direct welding of this invention is a back bar for direct welding that is held between electrode chips along with the welding part of the workpiece in the thickness direction and energized, and has excellent conductivity. a flexible core material made of a plurality of laminated thin plates, and a flexible plate material that also has excellent conductivity and is thicker than the thin plates, which is in contact with both surfaces of the flexible core material. Two surface protection plates, one in surface contact with the workpiece and the other in contact with the electrode, are tightened and fixed in the thickness direction at both lengthwise ends, and each thin plate and surface The protection plates are brought into sliding contact so that they can be relatively displaced in their length directions.

(Function) With this back bar for welding, the surface shape can be extremely easily formed into various shapes by bending and deforming both the flexible core material and the surface protection plate. Even if the back bar has a complex surface shape, the surface of the back bar can be easily and quickly formed into a shape that exactly corresponds to the surface shape of the welded part.

Also, since the welding back bar is flexible, it is possible to easily reshape the back bar applied to one type of work into the required shape for another type of work. .

(Example) This invention will be explained below based on illustrated examples.

FIG. 1 is a cross-sectional view showing one embodiment of this invention, in which 11 is a flexible core material with excellent conductivity.
Reference numeral 2 designates surface protection plates that are in contact with both surfaces of the flexible core material 11.

Here, the flexible core material 11 has a thickness of, for example, 1 to
The surface protection plate 12 fixed to the flexible core material 11 can be constructed by laminating the required number of thin copper plates 11a of about 2 mm without adhering them to each other. thickness is 3
It can be constructed from a copper plate with a thickness of ~5 mm.

The flexible core material 11 configured in this manner has the advantage that each thin copper plate 11a is thin, and each thin copper plate 11a can be relatively freely displaced relative to each other, so that it can be shaped into a desired shape. This makes bending deformation extremely easy, and the surface protection plate 12
Since it is made of copper and has a thickness of about 3 to 5 mm, it not only exhibits excellent conductivity but also effectively prevents deformation of the flexible core material 11 by the electrode chips. It can exhibit sufficient flexibility.

In the illustrated example, such a flexible core material 11
and the respective surface protection plates 12 that are in contact with both surfaces of the flexible core material 11, and a screw member 13 that penetrates the flexible core material 11 at one end thereof.
and a surface protection plate 12 at the other end thereof.
They are mutually tightened and fixed by a belt 14 wrapped around 12. Here, the tightening by the screw member 13 includes screwing its tip into an internal thread provided on the surface protection plate 12.
This can also be done by screwing a nut onto the tip.

In the back bar formed by tightening and fixing the flexible core material 11 and the surface protection plate 12 in this way,
When bending and deforming it into a curved shape as shown in FIG. Based on the relative displacement, desired plastic deformation can be easily brought about without impairing the flexibility of the flexible core material 11 and the surface protection plate 12.

FIG. 2 is a sectional view showing another embodiment of this invention, and this example has screw members 15, 15 passed through them at both ends of the flexible core 11 and the surface protection plates 12, 12. A nut 16 screwed onto the tip of each screw member 15 is used to tighten and fix them, and the long holes 12a and 11b provided in at least one of the surface protection plate 12 and the flexible core member 11 are Therefore, free relative displacement of each thin copper plate 11 and surface protection plate 12 is ensured.

Therefore, also in this example, when bending and deforming the welding back bar as shown in FIG. 2b, the respective through holes 11b and 1
By the action of 2a, it is shaped into the desired shape,
It can be plastically deformed very easily.

Such welding back bars mainly change the surface shape of the workpiece by bending and deforming it.
After forming the weld into a shape that corresponds sufficiently precisely to the surface shape of the welding part, as described in the prior art, as shown in perspective view in FIG.
It is attached to a predetermined position, preferably movably in the direction of its thickness.

Here, if the welding back bar is made movable in its thickness direction, when the welding part of the workpiece is held together with the backbar by the electrode tip of the welding gun, it is difficult to remove the welded part of the workpiece or other inconvenient parts. Deformation can be sufficiently prevented.

As mentioned above, the welding back bar here has sufficient flexibility, so when it is applied to a workpiece W as shown in FIG. The surface shape can be easily and quickly formed into a shape that makes surface contact with the welding part Wp with sufficient precision,
In this application state, the back bar can fully perform its original function.

(Effect of the invention) Therefore, according to this invention, since the welding back bar has flexibility, the surface shape of one of the back bars can be changed to the surface shape of the welded part by a simple operation. The surface shape of the back bar can be easily reshaped to the required shape for other types of workpieces.

[Brief explanation of the drawing]

1 and 2 are partial sectional views showing an embodiment of this invention, FIG. 3 is a perspective view showing a welding back bar in an installed state, and FIG. 4 is a perspective view showing a conventional welding back bar in an installed state. FIG. 5 is a schematic plan view illustrating the application state of the back bar. 11... Flexible core material, 11a... Copper thin plate, 12
...Surface protection plate, 13, 15...Screw member, 14...Belt, 16...Nut.

Claims (1)

[Claims for Utility Model Registration] A back bar for direct welding that is sandwiched between electrode chips along with the welding part of a workpiece in the thickness direction and energized, and is made by laminating a plurality of thin plates 11a with excellent conductivity. The flexible core material 11 was brought into contact with both surfaces of the flexible core material, which also had excellent conductivity, and
Two surface protection plates 12 are made of a flexible plate material thicker than the thin plate 11a, one of which is in surface contact with the workpiece, and the other is in contact with the electrode, at both ends in the length direction. A back bar for direct welding which is tightened and fixed in the thickness direction, and in which each of the thin plates 11a and the surface protection plate 12 are slidably contacted in a manner such that they can be relatively displaced in the length direction.