JPH049108Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an electrode tip changing device for resistance welding.
This invention relates to an electrode tip exchange device for extracting an electrode tip, which is a consumable item, from a shank on the arm side of a welding gun, and attaching a new polished electrode tip to the shank.

(Prior Art) Conventionally, in a resistance spot welding machine, an operator manually replaces an electrode tip attached to a shank on the arm side of a welding gun.
When spot welding surface-treated steel sheets such as galvanized steel sheets, the life of the electrode tip is extremely short.In particular, robot spot welding machines perform multi-spot welding of dozens or more points with one welding gun, so the life of the electrode tip is extremely short. The frequency of replacement of the electrode chips is high, and a lot of time and effort is spent on replacing the electrode chips, resulting in a decrease in productivity. In addition, when replacing electrode tips manually, it is necessary to install various auxiliary equipment such as scaffolding to improve the work and ensure safety.
There is a problem in that the welding equipment becomes larger as a whole and the equipment cost increases accordingly. Another method of managing the electrode tip is to polish the electrode tip while it is attached to the electrode tip holder, but in the case of special electrode tips that are difficult to polish, polishing errors and polishing can be avoided. Since the precision is poor and welding defects are likely to occur, the management of the electrode tips depends on replacing them.

In order to eliminate this kind of trouble, in other words, without manual work by workers, for example,
A device having an electrode tipping tool with a wedge-shaped tip as described in Japanese Utility Model Publication No. 41482, and a device using a lever action as described in Japanese Utility Model Application No. 61-41483. Apparatus with electrode chip removal tools have been devised.

(Problems that the invention attempts to solve)
According to the automatic electrode tip changing device described in Publication No. 41483, the electrode tip can be removed by mechanical force without manual intervention by an operator.
The former uses wedge action, and the latter uses lever action, so in both cases, in order to obtain sufficient force to pull out the electrode tip,
There is a problem in that the moving length of the electrode chip removal tool becomes large, and the device therefore becomes large, which is undesirable in terms of space and cost.
The present invention aims to solve these problems.

(Means for solving the problem) A shaft is supported rotatably around its axis on a base, a chip removal tool is integrally attached to one end of the shaft, and a plurality of new polished electrode chips are installed. a positioning/guide for slidably supporting an electrode chip supply holder to be accommodated is provided on the base;
In addition, the chip removing blade is provided with a recessed portion, and the recessed portion has a stepped portion formed by the straight surface of the shank and a surface for fitting an electrode tip provided on the shank on the arm side of the welding gun. A blade section is provided for insertion.

(Function) When exchanging the electrode tip, first move the shank together with the electrode tip to the recess of the chip removal tool, and the blade of the recess is connected to the electrode chip mating surface provided on the shank and the shank. The electrode chip is inserted into a stepped part made of a straight surface of the shank, and then the chip extractor is rotated via a shaft to reliably extract the electrode chip from the shank in a short time. I can do it. Next, the pair of shank from which the electrode tip has been extracted is moved by a welding robot to a fixed position, that is, brought to an electrode tip supply holder containing a new polished electrode tip.
When the distance between the pair of shank is narrowed, a new electrode chip is fitted into the electrode fitting part of both shank, and when the distance between both shank is widened, the fitted electrode chip is fitted into the electrode fitting part of both shank. comes off from the electrode tip supply holder. In this way, the electrode tip is replaced.

(Example) FIG. 1 shows an example of the present invention. Also, Figures 2 to 5 show details of the chip extractor shown in Figure 1, Figures 6 to 8 show its function, and Figures 9 and 10 show the positioning and guiding tool shown in Figure 1. Details of the electrode tip supply holder are shown.

In FIG. 1, 1 is a base, 2 is a chip extraction tool for extracting electrode chips 16, 16', which will be described later, and as seen in FIG. , 2b, and the recesses 2a, 2b have blade portions 2c, 2d, respectively. The chip removal tool 2 is integrally connected to one end of a shaft 5 which is rotatably supported on the base 1 through bolts 4 of the flange 3, and a swing lever is attached to the other end of the shaft 5. A knuckle 8 of a cylinder 7 is connected to the tip of the lever 6 by a pin 9.

10a and 10b are proximity switches for detecting the operating position of the lever 6. The switch 10a detects the position before operating, and the switch 10b detects the operating position of the lever 6, and the switch 10b detects the operating position of the lever 6. This is for detecting the position of the lever 6 when compressed air is supplied from an air compressor (not shown) and the chip removal tool is rotated integrally with the shaft 5 around the axis of the shaft 5. be.

Further, 11 is an arm of a robot welding machine (not shown), 12 is a metal fitting for attaching a welding gun to the arm 11, 13 and 13' are arms of the welding gun, and the arms 13 and 13' are equipped with a screw adapter 1.
4, 14' are screwed together, and the screw adapter 14, 1
4' is fitted with shank 15, 15',
The shank 15, 15' has electrode chips 16, 1
6' is fitted.

Furthermore, 17 is a positioning/guide attached to the base 1 for supplying new polished electrode chips, 18 is an electrode chip supply holder for supplying new polished electrode chips, and 19-
1, 19-2, 19-3, 19-4, and 19-5 are new polished electrode chips; 20 is a limit switch for detecting whether or not the electrode chip supply holder 18 is in the positioning/guide 17; 21
is a receiver for when the electrode chips fall out, and all polished electrode chips are supplied from the electrode chip supply holder 18, and immediately after that, the positioning and guide 17
This serves as a support for the electrode chip supply holder 18, which falls down when the electrode chips are used up. 23 is a limit switch, 24 is an operating lever of the limit switch 23, 25 is a hole several millimeters larger than the outer circumference of the electrode chip provided at the tip of the operating lever 24, and 26 is a flat plate portion provided at the tip of the operating lever 24. .

In the resistance welding electrode tip changing device constructed as shown in FIG. 1, it is possible to remove an electrode tip from the shank of a welding gun and to attach a new polished electrode tip to the shank.

First, extraction of the electrode chip will be explained.

A welding robot (not shown) predicts wear of the electrode tip based on signals such as count-up and selects an electrode tip replacement program. In accordance with the program, the welding robot alternately inserts the electrode tips 16 and 16' into the center of the hole 25 provided in the actuating lever 24 of the limit switch 23 in order to confirm the displacement of the electrode tips. At this time, if the electrode tips 16, 16' are misaligned due to deformation of the arms 13, 13' of the welding gun, the electrode tips 16 or 16' will rotate the operating lever 24 of the limit switch 23. , the limit switch 23 is activated and the electrode tip 16 or the electrode tip 16'
It is possible to confirm an abnormality in which the is not in the designated position. Then, an abnormality signal is output to the outside, and the welding robot stops further operations to prevent damage to the equipment. When no abnormality is found, the welding robot uses the recess 2a of the chip extractor 2 to extract the electrode chip 16.
Heshank 15 and electrode tip 16 move as shown in FIG. Thereafter, compressed air is supplied to the cylinder 7, and the piston rod of the cylinder 7 moves in the retracting direction. As a result, the shaft 5 is rotated via the swing lever 6, and the chip removing blade 2 connected to the shaft 5 is rotated.
Blade portion 2 provided in the recess 2a of the chip removing blade 2
c enters the stepped portion 15a formed by the tapered surface 15b for fitting with the electrode chip 16 provided on the shank 15 and the straight surface 15c of the shank 15 shown in FIG. Since it rotates around the center of rotation, it changes from the state shown in FIG. 6 to the state shown in FIG. 7, and then to the state shown in FIG. 8, and then rotates in a short period of time to remove the electrode tip 16 from the shank 15. Similarly, the electrode tip 16' can be extracted by the blade 2d provided in the recess 2b. On the other hand, a recessed portion 2 having a blade portion 2c
If there is only one of the recessed portions 2b having the blade portion 2d and the recessed portion 2d, the function thereof can be achieved. In other words, if one of the recesses 2a and 2b is used, the welding robot is operated and the welding gun is turned on.
Just flip it 180°.

After the extraction operation of the electrode tips 16, 16' is completed in this manner, a welding robot (not shown) alternately and lightly presses the flat plate portion 26 of the operating lever 24 with the shank 15, 15'. At this time, the operation of the welding robot is controlled so that if the electrode tips 16, 16' are removed, the limit switch 23 will not turn on, but if both or one of the electrode tips 16, 16' is not removed, it will be turned on. By doing so, it is possible to detect an abnormality when the electrode chips 16, 16' are not removed.

Next, the operation of attaching a new polished electrode tip to the shank 15, 15' of the welding gun from which the electrode tip 16, 16' has been removed will be explained.

An electrode chip supply holder 18 is pushed into the positioning/guide 17. This holder 18 is made several millimeters smaller than the inner dimensions of the positioning/guide 17. The electrode chip supply holder 18 has five holes arranged in a straight line into which electrode chips can be embedded facing each other, and new electrode chips 19-1, 19-2, 19-3, 19-
4, 19-5 are embedded in order, positioning and guide 1
7, as shown in FIG. 1, the embedded lowest electrode chip 19-1 is located at the lower end of the cutout groove 17a (see FIGS. 9 and 10) provided in the positioning/guide 17. This serves as a support to prevent the electrode chip supply holder 18 from passing through the positioning/guide 17 and falling. A welding robot (not shown) takes the shank 15, 15' of the welding gun from which the electrode tips 16, 16' have been removed, and operates a valve (not shown) to open the arms 13, 15' of the welding gun.
If 13' is made narrower on the electrode mounting side,
A new polished electrode chip 19-1 is fitted into the tapered portion of the shank 15, 15'. Next, when a valve (not shown) is operated so that the electrode mounting sides of the arms 13, 13' are expanded, the electrode chip 19-1 is removed from the electrode chip supply holder 18. Then, the electrode chip supply holder 18 loses the support of the electrode chip 19-1 and begins to fall, but the electrode chip 19-2 becomes the next support and stops. That is, with this mechanism, the welding robot only needs to come to the same location to pick up a new, polished electrode tip. This makes it possible to supply electrode chips without making the welding robot perform complicated operations.

In this way, a new polished electrode chip 19- is set in the electrode chip supply holder 18.
1, 19-2, 19-3, 19-4, 19-5 are removed, and the holder 18 becomes the positioning/guide 17.
If the electrode tip falls downward from the tip, the limit switch 20 detects this and issues an alarm. Therefore, a new electrode tip supply holder can be manually supplied within several hours until a new polished electrode tip is required. . Also, the limit switch 20 has been relocated so that only one or two new electrode chips remain.
It can also be used to detect and issue an alarm when an arbitrarily set number such as 1 or 3 is reached. Incidentally, if the number of holes for mounting the chips in the electrode chip supply holder 18 is increased, the time during which one electrode chip supply holder is used becomes longer.

It is also possible to incorporate the apparatus shown in FIG. 1 into a truck or the like in the same manner as the workpiece to be welded, and to perform the welding process sequentially. In this case, if control signals are sent and received by connecting the installed robot welding machine with a contact conductive device, there is no need to provide this device for each robot welding machine.

Note that depending on the shape of the welding gun that the welding robot has, it may not be possible to place the positioning/guide 17 vertically as shown in Figures 1, 9, and 10; however, the next electrode tip must be replaced. In the meantime, the positioning/guide 17 may be raised vertically or diagonally using a cylinder or the like. Alternatively, a lid may be provided on the pushing side and pushed by a spring. Alternatively, as shown in FIG. 11, the electrode chip supply holder 18 containing a large number of new polished electrode chips 19 and the positioning/guide 17 are placed horizontally, and the electrode chip supply holder 1
8 may be pulled toward the opposite side by using the weight 28 and the string 27.

FIG. 12 shows an embodiment in which a specially shaped electrode tip 19' is oriented by a hole provided in the electrode tip supply holder 18.

(Effects of the invention) The present invention has a chip removing tool at one end of the shaft which is rotatably supported around the axis on the base, and this chip removing tool is provided with a shank on the arm side of the welding gun. The shank has a recess with a blade that fits into the stepped part formed by the tapered surface for fitting with the electrode tip and the straight surface of the shank, so when replacing the electrode chip, the blade of the recess should be By inserting the electrode tip into the stepped portion and rotating the tip extracting tool via the shaft, the electrode tip can be reliably extracted from the shank in a short time. In other words, unlike conventional chips that use wedge action or lever action, the chip removal tool is a rotating type, so sufficient removal force can be obtained without increasing the size of the device. This makes it possible to use the same technology, which is advantageous in terms of space and cost. The base is also equipped with a positioning and guide for supporting an electrode tip supply holder that accommodates a new polished electrode tip, so that when installing a new polished electrode tip into the shank, the arm of the welding gun The welding robot only needs to bring the new electrode tip close to the predetermined position of the electrode tip supply holder and operate the arm. In other words, the welding robot only has to come to the same position to pick up the new electrode tip, without making the welding robot make any complicated movements. , it becomes possible to attach an electrode chip.

As described above, according to the present invention, it is possible to replace the electrode tip entirely by mechanical force without relying on human hands, and it is also possible to downsize the entire device. The welding robot does not have to make complicated movements when installing a new polished electrode tip, which simplifies the process of attaching a new electrode tip, improves the quality of resistance welded products, and reduces maintenance. Work efficiency will also improve.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is an enlarged plan view of the chip extractor shown in Fig. 1, Fig. 3 is a front view of Fig. 2, and Fig. 4 is the same as Fig. 2. A sectional view taken along cutting line A-A, FIG. 5 is also taken along cutting line B-
A sectional view taken along line B, FIG. 6 is an explanatory diagram of the first action of the chip extractor, FIG. 7 is an explanatory diagram of the second action, FIG. 8 is an explanatory diagram of the third action, and FIG. 9 is an explanatory diagram of the third action. Fig. 1 is an enlarged partially cutaway front view of the positioning/guide and electrode chip supply holder, Fig. 10 is a side view of Fig. 9, and Fig. 11 is another example of the present invention regarding the positioning/guide and electrode chip supply holder. FIG. 12 is a perspective view of one embodiment, and FIG. 12 is a partially cutaway plan view of still another embodiment. 1... Base, 2... Chip removal tool, 2a, 2
b... Recessed part, 2c, 2d... Blade part, 5... Shaft, 13, 13'... Arm, 15, 15'... Shank, 15a... Stepped part, 15b... Tapered surface for fitting, 15c ...Straight side, 16,1
6'... Electrode chip, 17... Positioning and guide,
18... Electrode chip supply holder, 19, 19',
19-1, 19-2, 19-3, 19-4, 19
-5, 19-6...New polished electrode chip.

Claims (1)

[Scope of utility model registration request] A shaft supported rotatably around an axis on a base, a chip removal tool integrally provided at one end of the shaft, and a plurality of new polished electrode chips provided on the base. a positioning/guide for slidably supporting an electrode chip supply holder, and the chip extracting tool includes:
It has a recessed part, and the recessed part has a blade part that fits into the stepped part formed by the straight surface of the shank and the surface for fitting with the electrode tip provided on the shank on the arm side of the welding gun. Electrode tip changing device for resistance welding.