DE2541192A1 - Simultaneous dressing of electrodes in multi spot welding machines - using swivel fixture contg. row of driven grinding wheels - Google Patents

Abstract

A device for dressing the electrodes on multi-spot welding machines, during preselected welding pauses, consists of a grinding device provided with several grinding wheels mounted on one or more shafts driven by V-belts and a motor. The device is mounted on a pivot arm so that it can be swung into the working position. A slide carrying the grinding wheels can be driven forwards and backwards between the electrodes and the grinding wheels can be moved vertically or swung on a swivel to grind the working faces of the electrodes.

Description

Device for reworking electrodes on multi-point

Welding machines The invention relates to a device for reworking of electrodes on multi-point welding machines in preselected welding breaks.

Multi-point welding machines are used for point-like connections of sheets with sheets or of sheets with sheet metal profiles, pipes or the like.

Depending on the method of contact pressure, the current flow according to time, The strength and interval will be the ones leading the current from the machine to the part Welding electrodes more or less stressed. The choice of suitable effective sizes is particularly important for optimum performance in multi-spot welding machines Importance.

If the electrode force is chosen appropriately, i. H. Surface pressure during of the current flow, a greater number of perfect spot welds can be produced before scorch marks appear or weld spatter becomes visible.

Depending on the type and nature of the material to be welded and Type, cooling and shape of the electrodes and the requirements for the respective point connections the number of possible welds varies between 500 and 5,000 per electrode. The electrode effective area, which is found to be good in terms of shape and dimensions, must then pass through suitable special tools are restored.

Manual tools are used for reworking individual spot welding electrodes known. Hand tools of older design work on the principle of double cone milling cutters.

In the German PS 1174 438 a device is placed under protection, in which, in a manner known per se, a grinding element in a grinding element carrier is arranged and the carrier is displaceable in longitudinal guides of a holding frame and is rotatably guided and with rectilinear movement of the holding frame transversely to the Electrodes can be rolled rotatably along the drive means.

It is obvious that such devices are used in single-point welding machines to be firmly connected to the machine stand and directed at the electrode periodically to be used.

In the case of multi-point welding machines, the fact that at A large number of electrodes reworked the ones with the greatest change in shape Need to become.

In specialist publications it is believed that an automatic In principle, it is not possible to keep the working electrode clean on spot welding machines is possible.

The invention is based on the object of developing a device with all of them within a short time Spot welding electrodes automatically or can be reworked semi-automatically.

This object is achieved according to the invention in that a grinding device self-propelled consisting of several grinding wheels, which on one or more, Grinding wheel shafts driven by V-belts are stored out of the park position into the working position between the rows of welding electrodes that have moved apart swiveled in, one or more rows of welding electrodes at the same time with the preselected Employment reworked shaping and an additional device the horizontal movement and vertical or pivoting movement of the welding device before and after use performs combined According to the invention, a separate motor brings the effective parts the grinding device in a horizontally-oscillating motion, causing it on the one hand it is possible to rework at least two electrodes from a grinding wheel will. On the other hand, the grinding wheels are attached to the Electrodes removed themselves. The elastic binding of the discs comes from this process very contrary.

Furthermore, according to the invention, they correspond to the ideal electrode tip or a multiple thereof scanning body provided after those via the adjusting lever a large number of grinding wheels can be guided according to the type of copy grinding process.

The invention also includes the infeed of the grinding wheels is preselectable; in particular, however, according to the system of subdivided waves, the Pre-selectable grinding pressure on the workpiece. Thus, the follow-up performance is the Grinding wheels that form a grinding wheel shaft are proper always the same on the corresponding electrodes.

Finally, according to the invention, it is possible to use individual grinding wheel shafts to the tilt axis which is aligned with the drive shaft at different distances to bring and thereby also a non-aligned row of welding electrodes at the same time rework.

Since the rapid retraction and extension of the grinding device in the or from the working area of the electrodes is of crucial importance proposed according to the invention, the frame with the grinding device horizontally to move and then the grinding device obliquely upwards around the pivot axis to pivot.

When using the method of the device according to the invention a large number of electrodes at the same time in an automatic program sequence reworked.

The advantage is that on the one hand the entire workflow the electrode rework is very short. When producing large numbers of items one and the same parts to be welded, there is no further advantage at all wait for a deterioration in the welding quality of the spot points, but rather after a certain rhythm, the electrode rows by means of the automatic grinding device rework. This is a great advantage compared to the previously used method with continuous operation all spot welding electrodes z. B. after half a work shift to be completely exchanged and replaced by new ones. Also through the use of composite electrodes, possibly with a tungsten insert, is nowhere near a good one Welding performance achievable during an entire shift.

It's not so much a true-to-size regrinding with a rigidly mounted grinding wheel, but due to the elastic bond of the Wheel is achieved that the grinding wheel easily over the electrode edges and deburring them at the same time, The oscillating movement of the disc prevents the disc from forming on the electrodes and caused by the Matching the bond and filling to the hardness of the electrode material is one thing Targeted reworking of electrodes possible.

The invention is explained below with reference to soft voltages, the method that can be achieved with the device becomes clear: FIG. 1: grinding device in side view Figure 2: Movement device for horizontal and tilting movement the grinding device in side view Figure 3: Horizontal and tilting movements the grinding device, shown schematically Figure 4 * horizontal and vertical movements the grinding device, rail-guided, shown schematically Figure 5: Schematically illustrated oscillating movement of the grinding wheels to the electrodes.

Figure 1 shows a grinding device (i) as it is moved apart Electrodes (20 and 21) of a spot welding machine (19) are in the working position is.

On a longitudinally movable sliding carriage (8) is the Bracket (9) for the bearing points of the tilt axis (2) firmly attached. For the purpose of Positioning of the grinding wheels (7) opposite the electrodes (20) will the entire grinding unit is tilted around the tilt axis (2). The grinding wheels (7) which are attached to the grinding wheel shaft (6) are not shown V-belt driven by the grinding motor (3).

The center of the grinding motor shaft is also the center of the tilt axis. This makes it possible to use the grinding wheels (7) that are attached to the grinding wheel shaft (6) held in the adjusting lever (4) via the other arm of the adjusting lever (4) to be selected in the delivery device (5). This can depend on the type of Grinding machine infeed must be a fixed infeed dimension. In the delivery device (5) can of course also be spring-loaded or pneumatic with a preselected pressure certain contact pressure can be preselected.

Although not shown in Figure 1, it is easy to imagine that on a common tilt axis (2) several groups of adjusting levers (4) are movable each a group of grinding wheels (7) are stored and lead over feed devices (5) Grind with the same contact pressure. The tilting movement of the individual Adjusting lever groups (4) on the tilting axis (2) differ slightly from one another be.

The feed of the grinding wheels takes place on the one hand through the longitudinal movement of the grinding slide (8), which in turn is moved by means of a threaded spindle (10).

On the other hand, there is also an oscillating movement over the bearings that are combined with ball bushings is achieved in that from the motor for the oscillation (18) via a not shown in detail, but known linkage the grinding wheels with their storage in oscillating motion be moved.

An example of a device that uses the grinding device (1) which brings FIG. 1 from the parking position into the working position is shown in FIG. And it is assumed that a stable frame (14) the entire Device moves horizontally, which is expediently done by means of hydraulic cylinders is carried out.

After finishing the reworking of the grinding wheels (7) on the electrodes (20) it is necessary to quickly move the entire grinding device (1) horizontally the area of the welding electrodes (20 and 21) and then into a To turn off the parking position, which allows an unimpeded automatic welding operation.

In the lower area of the frame (14) rotates around the pivot axis (13) the swivel frame (11). The swiveling out of this swiveling frame (11) from the horizontal to the parking position is carried out by the cylinder (15) via chains (16) which actuate the chain wheel (17) firmly connected to the swivel frame (11).

It goes without saying that in the case of the threaded spindle (10) The grinding feed of the grinding slide selected via the geared motor, not shown (8) is moved on rollers (12) and the pivoting frame (11) is in a horizontal position also rests on rollers (12 ').

In Figure 3, the movement of the grinding carriage is shown schematically, which is brought from the working position to the parking position, where I. working position the grinding device II. Horizontally moved grinding device III. Grinding device swiveled up.

Another movement of the grinding carriage is provided in FIG namely, the grinding carriage is horizontal after leaving the working position it is moved upwards via rails from the working area of the welding machine procedure.

The oscillating movement of a plurality of grinding wheels is shown schematically in FIG illustrated. It should be shown which oscillation movement a grinding wheel carries out to rework the respective electrodes. The oscillatory movement of the Disc is explained with xl, x2, x3 and x4.

In a working example, electrodes with dimensions of 8 x 25 mm are used reworked at the same time. Commercially available grinding wheels are also used elastic bond and hardness 40 to 90 according to DIN 53456 and abrasive filling SiC. The reworking time was between 20 and 30 seconds for about 30 electrodes.

With an oscillating movement of about 35 minutes 1 will also be the grinding wheels are automatically removed in continuous operation, d. H. in one for that Spot welding kept favorable shape.

Claims (17)

Claims X device for reworking electrodes on Vielpunt-Sc welding machines in the preselected welding breaks, as there are no c h n e t that a self-propelled grinding device (1) consisting of several Grinding wheels (7), which are driven on one or more, via V-belts Grinding wheel shafts (6) are mounted, from the parking position to the working position swiveled in between the rows of welding electrodes (20, 21) that have moved apart, Forming one or more welding electrodes at the same time with a preselected position reworked and an additional device the horizontal movement and the vertical or pivoting movement of the grinding device (1) before and after use combined performs. x) rows 2. Device according to claim 1, d a d u r c h g e k e n It is noted that a separate motor (18) drives the grinding wheels that are in engagement (7) of the grinding device (1) additionally in a horizontal, oscillating movement offset and thereby at least two electrode tips from one grinding wheel (7) to be reworked. 3. Apparatus according to claim 1 and 2, d a d u r c h g e k e n n z e i c h n e t that grinding wheels (7) with elastic bond on the material base Foamed elastomers "are used, which promote profile reshaping. 4. Apparatus according to claim 1 to 3, d a d u r c h g e k e n n z e i c h n e t that bumps in the desired shape of the electrode tip or a multiple of it serve as a scanning body after which the adjusting lever (4) is guided will. 5. Apparatus according to claim 1, 2 and 4, d ad u r c h g e k e n n notices that brush discs made of metal or metal alloys are used are used to rework the welding electrodes. 6. Apparatus according to claim 1 to 4, d a d u r c h g e k e n n z e i c h n e t that the infeed of the grinding wheels (7) via an infeed device (5) can be preset. 7. Apparatus according to claim 1 to 6, d a d u r c h g e k e n n z e i c h e t that the grinding wheel shaft, which is centrally driven via V-belts (6) is divided for the grinding wheels (7) and each one or more of these Grinding wheels or grinding wheel groups with pre-selected contact pressure the electrodes rework. 8. Apparatus according to claim 4, 6 and 7, d ad u r c h g e k e n n z e i c h n e t that the grinding wheels located on a grinding wheel shaft (6) (7) can be peeled off with a diamond. 9. Apparatus according to claim 7, d a d u r c h g e k e n n z e i c h n e t that the individual grinding wheel shafts carrying the grinding wheels (7) (6) do not align, d. H. the distance between the tilt axis (2) with the motor shaft aligns and the individual grinding wheel shafts (6) is different to non-aligned To be able to edit rows of electrodes. 10. The device according to claim 1 to 9, d ad u r c h g e k e n n z e i c h n e t that alternate employment both for reworking the lower Row of electrodes when retracting as well as for reworking the upper row of electrodes is possible when extending. 11. The device according to claim 1 to 10, d ad u r c h g e k e n n shows that a suitable rail guide determines the path after which the entire grinding device (1) after reworking from the working position in the area of the welding electrodes only horizontally at first and then vertically elevated into the parking position in a manner known per se by means of hydraulic elements is proceeded. 12. The device according to claim 1 to 10, d ad u r c h g e k e n n z e i c h n e t that after reworking the frame (14) the grinding device (1) moves horizontally out of the area of the welding electrodes so that the Grinding device can be pivoted upwards about the pivot axis (13) and the electrodes are released for subsequent welding work. 13. The device according to claim 1 to 12, d ad u r c h g e k e n n z e i c h n e t that the grinding device with one or more suction devices is provided to keep the grinding dust directly above the grinding wheels suction, whereby the suction hood is divided in the case of split grinding wheel shafts. 14. The apparatus of claim 1 to 12, ri d u r c h g e k e n n notices that the movements are preprogrammed using preselector switches: I. Swiveling the swivel-in frame (11) II. Retraction of the grinding device (1) by means of a frame (14) between the electrodes (20 and 21) that have moved apart the blocked welding machine (19) III. Reworking the welding electrodes (20) by means of grinding wheels (7) which are set in oscillating motion via the motor tal8) and received grinding feed via threaded spindle (10) IV. Completion of III after time preselection V. Extending the grinding device (1) out of the area of the Electrodes (20, 21) by means of frame (14) VI. Swiveling up the swivel frame (11) VII. Release of the previously blocked welding machine tal9) 15th Method using the device according to claim 1, d u r c h e k e n n z e i c h n e t that a self-propelled grinding device (i) consists of several grinding wheels (7) on one or more grinding wheel shafts (6) stored from the parking position to the working position between the moved apart Rows of welding electrodes (20, 21) swiveled in and after reaching the working position between the electrodes the grinding wheels with elastic bond one or more Rework rows of welding electrodes simultaneously with the preselected position. 16. The method according to claim 15, d a d u r c h g e k e n n z e i c h n e t that at least the grinding wheels (7) with grinding wheel shafts (6) over a separate motor (18) controlled a horizontal oscillating movement, each one grinding wheel by oscillating movement at least two electrodes regrinds. 17. The method according to claim 16, d a d u r c h g e k e n n z e i c h n e t that in addition to the oscillating movement, the adjusting lever (4) for the grinding wheels (7) are guided with probes over the scanning body, which is the ideal Electrode shape or a multiple thereof correspond, whereby after per se known method of copy grinding, the electrodes are reground according to Meisterstück will.