EP1157758B1 - Device for removing dents from metal sheets - Google Patents

Abstract

The device has a holder and a number of adjacent pulling electrodes that can be independently longitudinally movably mounted on the holder. The electrodes have a welding tip on one end that can be rounded, a contact surface on the other end for a welding electrode and a stop acting in the pulling direction. The holder is a metal holder body with isolated lead throughs for the electrodes.

Description

The invention relates to a device according to the preamble of claim 1 with which one can remove bumps from sheet metal by pulling out the bump. For this purpose, it is known, for example, to glue into the bump an adapter to attach to the adapter a rod and a slide hammer, and knock out the bump gradually with the slide hammer. Then the adhesive adapter is removed again.

There is already known a device for extracting bumps from sheets (EP-A-916424), which has a holder in the form of a rod with a plurality of juxtaposed pull electrodes. The traction electrodes are mounted in their own longitudinal direction independently of each other displaceable on the holder. They have at their one end a welding tip and at the other end a contact surface for a welding electrode. In the pulling direction a stop is provided.

Also known is a device for extracting bumps from sheets (JP 11-57857), in which passages for electrodes are present in a metallic receiving body. The electrodes have an insulation, which can be displaced together with the electrodes in the axial direction of the electrodes relative to the receiving body.

The invention is based on the object to provide a device for extracting bumps from sheets, with which even larger bumps can be removed in a single operation.

To solve this problem, the invention proposes a device with the features mentioned in claim 1. Further developments of the invention are the subject of dependent claims.

The device is used as follows. The traction electrodes are inserted into the bump so that their welding tips rest on the metallic sheet of the bump. Subsequently, a welding electrode is brought into contact with the contact surface at the other end of the pulling electrode and a welding current is conducted into the pulling electrode. As a result, the pulling electrode is welded firmly to the sheet. This will be done one after the other made of the plurality of pulling electrodes. Then pull on the holder to simultaneously pull all the pull electrodes outwards and pull out the bulge. Then the pulling electrodes must be released from the sheet, which can be done with tools. By providing a plurality of pulling electrodes, which are arranged side by side, not only small bumps, but also larger bumps in as few operations can be removed. The arrangement of the traction electrodes can, for example, be along a line, preferably equidistant from one another, or else according to another pattern. This may depend on the shape of the bulge. When pulling out the tension electrodes are with their attacks on a mating surface, which is formed for example by the holder. The displaceability of the traction electrodes makes it possible to use a plurality of traction electrodes which need not be specially adapted to the shape of the bulge.

The use of a metallic receiving body makes it possible to manage with a small, yet stable mount. The bushings serve to support and support the drafting electrodes for their displacement, being isolated from each other by the insulation.

It is possible to release the drafting electrodes from the sheet after pulling out the bump by means of a separate tool or device. It is particularly useful if such a device for releasing the traction electrodes is integrated in the device.

One possibility for releasing the welded-on tension electrodes from the metal sheet is that the tensile electrodes are designed or held individually or jointly rotatable about their longitudinal axis. This measure can be provided in the device according to the invention. Then you can use a tool, such as a wrench, an electrode rotate about its longitudinal axis, which leads to shearing of the weld between the tip of the tension electrode and the sheet. In the simplest case, the stop of the pulling electrode can be formed by a hexagon, which then also forms key surfaces for rotating the pulling electrode with the aid of a wrench. It is also conceivable that the traction electrodes are connected to each other, for example by means of gears, so that the rotation of a single traction electrode leads to the rotation of all other traction electrodes.

As mentioned at the beginning, after attaching all tension electrodes to the device or the holder is pulled. The invention now proposes to provide the device with a device for applying or applying a tensile force on the tension electrodes together.

For example, it may be a device which is supported between the holder and the sheet and is designed such that it can increase the distance between the holder and the sheet, for example by means of spreading elements or the like.

It is also proposed that the device for applying a tensile force can be releasably attached to the device in order not to be in the way when welding the traction electrodes.

For example, the device can be inserted in guides. It is also possible that the means for applying a tensile force is pivotally mounted on the device, in particular the holder. It can then be arranged so that it does not interfere with the welding, but still remains constantly on the device.

In development of the invention can be provided that the traction device has a slide bar and a slide hammer. Then, in the usual way, the slide hammer can be moved along the slide bar and hit against a stop.

Another proposed by the invention possibility of applying a tensile force on the holder, is to use a lever supported on the sheet metal, with which the device is connected via a tension element.

According to the invention can also be provided that the device has a connection option for connection to a tensile force generator, which is already present in a workshop, such as a pulley, a body straightening bench or the like. The connection possibility can be a towing eye in the simplest case. Other connection options are conceivable, depending on the type of Zugkrafterzeugers.

The displaceability of the traction electrodes relative to the holder, in order to make the device particularly flexible, exploited by means of a spring action, that the traction electrodes always abut against their stop, regardless of the orientation of the device, which serves to drop the traction electrodes from their Prevent guides. The starting position of the traction electrodes is set in this case by the spring action.

In a further development of the invention it can be provided that the starting position of the traction electrodes for each pulling electrode is individually adjustable, in particular by an adjustment of the stops or a cooperating with the stops counter-attack. Before attaching the traction electrodes, therefore, the initial position can be set as it would correspond to the shape of a sheet without dent.

In a further development of the invention can be provided that the device has a ground electrode, which can be brought into connection with the sheet. It is particularly advantageous when the ground electrode is arranged in isolation on the holder, similar to the tension electrodes, and spring-loaded in the direction of the sheet metal. The ground electrode is then acted upon by the spring against the sheet when the welding takes place, so that the fitter no longer needs to deal with this.

Fig. 1

einen Schnitt durch eine erste Ausführungsform;

Fig. 2

eine teilweise geschnittene Seitenansicht der Ausführungsform nach Fig. 1;

Fig. 3

in vergrößertem Maßstab einen Schnitt während des Verschweißens;

Fig. 4

mehrere Muster von Anordnungen von Zugelektroden;

Fig. 5

das Aufbringen von Zugkraft auf eine Vorrichtung mit Hilfe eines Hebels;

Fig. 6

eine der Fig. 1 entsprechende Darstellung bei einer weiteren Ausführungsform mit abnehmbarer Zugeinrichtung;

Fig. 7

eine teilweise geschnittene Seitenansicht der Ausführungsform nach Fig. 6;

Fig. 8

eine Seitenansicht einer weiteren Ausführungsform;

Fig. 9

eine Stirnansicht der Ausführungsform nach Fig. 8.

Further features, details and advantages of the invention will become apparent from the following description of preferred embodiments of the invention and from the drawing. Hereby show:

Fig. 1

a section through a first embodiment;

Fig. 2

a partially sectioned side view of the embodiment of FIG. 1;

Fig. 3

on an enlarged scale, a cut during welding;

Fig. 4

a plurality of patterns of train electrode assemblies;

Fig. 5

the application of tensile force to a device by means of a lever;

Fig. 6

a representation corresponding to Figure 1 in a further embodiment with removable drawbar.

Fig. 7

a partially sectioned side view of the embodiment of FIG. 6;

Fig. 8

a side view of another embodiment;

Fig. 9

an end view of the embodiment of FIG. 8.

In Figures 1 to 3, a first embodiment of a device according to the invention is shown, with which you can pull bumps from sheet metal. In the figures, the sheet is just shown, since it is initially only about the representation of the structure of the device.

The device contains a holder 1, which is designed as a receiving body 2 in the illustrated embodiment. The receiving body 2 includes four mutually parallel bores, in each of which an insulating bushing 3 is inserted. The insulating bush 3 includes on its side facing the sheet 4 a circumferential collar 5, which limits the insertion of the insulating bushing 3 in the bore of the receiving body 2. The length of the insulating bushes 3 corresponds to the length of the holes in the receiving body. 2

In the inner openings of the insulating bushes 3, a pull electrode 6 is used in each case. The pulling electrodes 6 are formed as substantially cylindrical pins, so that they are well guided. At their end remote from the sheet metal, they contain a head 7 which has a contact surface 8 for a welding electrode 9 on its end face. The contact surface 8 is formed as a recess so that the rounded tip of the welding electrodes 9 finds a good contact surface.

The head 7 has a transverse extent which is greater than the outer diameter of the insulating bushes 3.

At the end facing away from the head 7, the pulling electrode 6 forms a welding tip 10, which is slightly rounded. The transition between the cylindrical part of the pulling electrode 6 and the welding tip 10 is conical. In the region of the transition between the conical region 11 and the cylindrical region of the pulling electrode 6, a securing ring 11 is attached.

Between the widened end 5 of the insulating bushing 3 and the securing ring 11 extends a compression spring 12, which acts on the pulling electrode so that the welding tip 10 is moved as far as possible from the receiving body 2 out. This caused by the spring 12 movement is limited by the concern of the head 7 of the pulling electrode 6 on the surface of the receiving body. 2

As can be seen from FIG. 2, the receiving body 2 contains a total of four such pulling electrodes 6, which are arranged at the same distance next to one another and which also have the same length. The heads 7 are formed in the shape of a hexagon, so correspond in shape to the usual hexagonal heads of screws. They have, see Figure 2, a mutual distance.

The receiving body 2 has the shape of a hexagonal prism with a longitudinal axis which is perpendicular to the axes of the holes and the traction electrodes 6. In the region of its two ends of the receiving body includes a cylindrical projection 13 which engages through an opening of a tab 14 therethrough. The outside of the tab 14 remaining part of the projection 13 has a retaining ring, which prevents the sliding of the tab 14. As a result, a tab 14 are pivotally mounted at both ends of the receiving body 2. The tabs 14 have approximately the shape of elongated rectangles. At their ends facing away from the storage on the receiving body 2, the tabs are pivotally mounted on projections 15 of a cross-beam 16 in a similar manner. The cross-beam 16 has a shape similar to the receiving body 2. In the cross-beam 16, a tension bolt 17 is screwed centrally between its two ends, which contains a stop nut 18 at its free end. At the stop nut 18 can be attacked with a pulling device to pull the device.

The device is used as follows, see in particular the figure 3. The holder is placed with the traction electrodes on the plate 4. The tabs 14 are pivoted so that the heads 7 of the tension electrodes are exposed. The receiving body 2, for example by means of the tabs 14, pressed something against the sheet, so that the heads 7 of the tension electrodes 6 no longer rest against the receiving body 2, as shown in Figure 3. Now the welding electrode 9 is pressed onto the contact surface 8 and sent a welding current through. The welding current leads to a welding of the welding tip 10 of the pulling electrode to the sheet 4. Subsequently, a second pulling electrode 6 is welded firmly to the sheet 4 in the same way until finally all the welding electrodes 6 are welded to the sheet 4.

The result of such a welding on a bump 19 having sheet 4 is shown in Figure 5. Now, a lever 20 is used which has a support plate 21 in the region of its one end. With this support plate, the lever 20 is placed at a different location of the sheet 4. The stop nut 18 is unscrewed from the tension bolt 17 and the tension bolt 17 is inserted between the two webs 22, 23 of the lever 20 therethrough. Subsequently, the stop nut 18 is again on the tension bolt 17th screwed. Now the fitter attacks the handle 24 of the lever 20 and pulls the device away from the sheet 4 perpendicular to the surface of the sheet. In this case, a tensile force is first exerted on the two middle traction electrodes, since the heads 7 of the other two traction electrodes are not yet present on the receiving body 2. Only when these heads 7 rest, a force is applied to the associated traction electrodes. After appropriate pivoting of the lever 20, the bulge 19 is pulled out, so that the sheet 4 again runs flat, as it should be. Since the transverse dimension of the heads 7 of the pulling electrodes 6 is greater than the outer diameter of the insulating bushes 3, no force is actually transmitted via the insulating bushes 3 during pulling. The stopper is formed between the underside of the heads 7 and the top of the receiving body 2.

In the embodiment according to FIGS. 1 to 3, the pulling electrodes 6 are arranged equidistantly along a line. However, the traction electrodes can also be arranged according to a different pattern. FIG. 4 a shows the arrangement as it corresponds to the embodiment according to FIGS. 1 to 3.

FIG. 4 b shows an arrangement in which the pulling electrodes 6 are arranged along a circle.

FIG. 4 c shows an arrangement in which the pulling electrodes are arranged along the sides of a rectangle. Of course, other patterns of arrays of electrodes are possible.

Now to the embodiment according to FIGS. 6 and 7. The traction electrodes are here designed and held in the same way as in the previous embodiment, so that this part of the description will not be repeated. The receiving body 25 has in the region of its two longitudinal sides 26 each have an undercut groove 27 on its upper side. These two arranged on the remote longitudinal sides 26 grooves 27 form a guide for a device with which a tensile force on the receiving body 25 can be exercised. The means for applying the tensile force includes a U-shaped yoke 28, in which the ends of the legs 29 have on their inner sides a groove 27 corresponding complementary formation. The yoke 28 can be pushed onto the end face 30 of the receiving body 25, wherein the projections on the inner sides of the legs 29 engage in the grooves 27. Thereby, the yoke 28 is fixedly connected in the direction perpendicular to the sheet 4 with the receiving body 25. In the web of the yoke 28, a tie bolt 17 is screwed, which also has a stop nut 18. At this drawbar can be attacked in the same manner as in Figure 5.

In addition, the receiving body 25 of the embodiment according to FIG. 6 and FIG. 7 contains a further bore which is insulated by an insulating bush 3 and runs parallel to the bores for the pulling electrodes 6. In this guide, a ground electrode 31 is slidably guided, which is also acted upon by an indicated compression spring against the sheet 4. With the aid of this ground electrode 31, the current is conducted to the sheet 4. This ground electrode makes it unnecessary to supply the current to the sheet 4 in any other way.

FIGS. 8 and 9 greatly simplify another possibility as to how a device according to the invention may look. There is again a receiving body 2 with a plurality of pulling electrodes 6 present. On the rectangular in this case in cross section receiving body 2, a cage 32 is pushed from its front side, which is formed as a square hollow profile with a slot on one longitudinal side. The inner opening 33 of this profile corresponds in width to the width of the receiving body 2. When pushing the traction electrodes get into the slot 34 to lie so that they can protrude through the slot down. In the pull-off electrodes 6 facing away from the top 35 of the cage, a slide bar 36 is screwed, on which a slide hammer 37 slides. At the outer end of the slide bar 36, a handle 38 is attached to a stop surface 39 for the slide hammer 37. After the tensile electrodes have been firmly welded, the installer with the sliding hammer 37 strikes against the abutment surface 39 until the bulge has been pulled out.

After the bulge 19 has been pulled out of the sheet, the traction electrodes still have to be separated from the sheet 4. For this purpose, in the embodiment according to Figure 1 to 3, the pulling device with the tabs 14 again swung laterally, similar to Figure 3. Then the fitter attacks with a wrench on the hexagonal heads 7 of the traction electrodes 6 and twisted them. As a result, the connection between the sheet 4 and the welding tips 10 is sheared off.

In the embodiments according to the other figures, the pulling device is pulled out laterally and then proceeded in a similar manner.

Claims (15)

1. Appliance for pulling out dents (19) in sheet metals (4), with

   1.1 a holder designed as a metallic receptacle (2, 25),

   1.2 a plurality of dent-puller electrodes (6) arranged adjacent to one another, which

   1.2.1 in their longitudinal direction, are supported on the holder in a manner allowing them to be shifted independent of one another, and

   1.2.2 on their one end is, if necessary, a rounded welding tip (10) and

   1.2.3 exhibits a contact surface (8) for a welding electrode (9) on its other end,

   1.2.4 it is provided with a limit stop that is effective in the pulling direction and

   1.2.5 spring loaded to ensure that it lies on the limit stop,
   characterized in that

   1.3 the holder exhibits insulated passages for the dent-puller electrodes (6), whereby

   1.4 insulated bushes (3) are inserted in the passages of the receptacle.
2. Appliance according to claim 1, wherein the starting position of the dent-puller electrodes (6) is individually adjustable, especially by shifting the limit stops.
3. Applicane according to one of the preceding claims, wherein a device is provided for detaching the dent-puller electrodes (6) from the sheet metal (4).
4. Appliance according to one of the preceding claims, wherein the dent-puller electrodes (6) are formed or held such that they can be rotated about their longitudinal axis for detachment purpose from the sheet metal (4) singley or in common.
5. Applicance according to claim 4, wherein at least one dent-puller electrode (6) exhibits a spanner surface for applying a tool.
6. Appliance according to one of the preceding claims, wherein a device is provided for applying a pulling force on the dent-puller electrodes (6) combined.
7. Appliance according to claim 6, wherein the device for applying a pulling force is supported between the holder and the sheet metal (4) and is shaped for lifting the holder.
8. Appliance according to claim 6 or 7, wherein the device for applying a pulling force is detachable from the appliance.
9. Appliance according to one of the claims 6 to 8, wherein the device for applying the pulling force is attached such that it can be inserted in guides on the appliance.
10. Appliance according to one of the claims 6 to 8, wherein the device for applying the pulling force is attached such that it can be swiveled on the appliance.
11. Appliance according to one of the claims 7 to 10, wherein the device for applying the pulling force exhibits a motion bar (36) and a slide hammer (37).
12. Appliance according to one of the claims 6 to 10, wherein the device for applying a pulling force comprises a connecting means for a lever (20).
13. Appliance according to one of the claims 6 to 10, wherein the device for applying a pulling force comprises a connecting means for an external device for producing a pulling force.
14. Appliance according to one of the preceding claims, comprising a ground electrode (31).
15. Appliance according to claim 14, wherein the ground electrode (31) is arranged in isolated manner on the support and is spring-loaded against the sheet metal (4).

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