WELDING ELECTRODE UNIT

Abstract

A welding electrode unit may include a repositioning device that is movable. The repositioning device may include a stored-energy means by way of which a welding electrode connected directly or indirectly with the stored-energy means can have a force applied to it for the purpose of a repositioning movement. The repositioning device can be moved into a welding position by way of a forward movement and can be locked in the welding position.

Claims

1.-15. (canceled)

16. A welding electrode unit comprising: a repositioning device that is movable and has a stored-energy means; and a welding electrode connected directly or indirectly to the stored-energy means such that the stored-energy means can apply a force to the welding electrode for purposes of a repositioning movement, wherein the repositioning device can be moved into a welding position by way of a forward movement and can be locked in the welding position.

17. The welding electrode unit of claim 16 wherein the forward movement is uncoupled from the repositioning movement.

18. The welding electrode unit of claim 16 further comprising a toggle lever mechanism for locking the repositioning device in the welding position.

19. The welding electrode of claim 18 wherein the toggle lever mechanism is connected with an energy source, wherein the forward movement is controllable by an energy flow from the energy source to the repositioning device by way of the toggle lever mechanism.

20. The welding electrode of claim 19 wherein the energy source comprises at least one of a compressor, a pump, or a pneumatic cylinder.

21. The welding electrode unit of claim 16 wherein a time at which the forward movement occurs is offset from a time at which the repositioning movement occurs.

22. The welding electrode unit of claim 16 wherein a forward direction along which the forward movement occurs is established by a column guide.

23. The welding electrode unit of claim 16 wherein the stored-energy means comprises at least one of a pressure spring, an elastomer cylinder, a hydraulic cylinder, or a pneumatic cylinder.

24. The welding electrode unit of claim 16 wherein the repositioning device comprises at least one of an adjustment screw or a sensor means for energy measurement.

25. The welding electrode unit of claim 16 wherein the repositioning device is at least one of jacketed at least in part by a housing or disposed on a base plate.

26. The welding electrode unit of claim 16 wherein the welding electrode is connected to the stored-energy means by way of a tappet and the repositioning device is disposed on a base plate, wherein the base plate has a recess through which the tappet can be passed.

27. The welding electrode unit of claim 16 further comprising an adapter disposed between the welding electrode and a tappet, wherein the adapter is adaptable to a work piece to be welded.

28. A method for welding comprising: moving a welding electrode into a welding position by a forward movement; locking a position of a repositioning device connected to the welding electrode; and applying directly or indirectly a force to the welding electrode for a repositioning movement.

29. The method of claim 28 wherein the forward movement is uncoupled from the repositioning device.

30. The method of claim 29 wherein a toggle lever mechanism is used to uncouple the forward movement from the repositioning device.

31. The method of claim 28 wherein the welding electrode is part of a welding electrode unit that comprises a repositioning device that is movable and has a stored-energy means, wherein the welding electrode is connected directly or indirectly to the stored-energy means such that the stored-energy means can apply a force to the welding electrode for purposes of the repositioning movement, wherein the repositioning device is positioned for welding by way of the forward movement.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0028] FIG. 1, in a perspective view, shows a welding unit according to a first exemplary embodiment of the present invention.

[0029] FIGS. 2a und 2b, in different side views, in each instance, show the welding electrode unit according to the first exemplary embodiment of the present invention in a basic position.

[0030] FIGS. 3a und 3b, in different side views, in each instance, show a welding electrode unit according to a first exemplary embodiment of the present invention in a welding position.

EMBODIMENTS OF THE INVENTION

[0031] In the different figures, the same parts are always provided with the same reference symbols, and will therefore also be identified or mentioned only once, in each instance.

[0032] In FIG. 1, in a perspective view, a welding electrode unit 100 according to an exemplary embodiment of the present invention is shown. Such a welding electrode unit 100 is an integral part, for example, of a production system in which a component for a vehicle, such as an engine compartment hood, for example, is shaped and joined. In this regard, it is conceivable that one or more work pieces 12 are first folded and subsequently welded during a welding process, at a weld 14, in the production system. Preferably, the welding process is a projection welding process. In the production system, the welding electrode unit 100 is responsible for welding. In this regard, the welding electrode unit 100 comprises a welding electrode 13, which is disposed on a tappet 11 by way of an adapter 18. In a basic position of the welding electrode unit 100 illustrated in the figure, the tappet 11 is moved in relative to a base plate 5, thereby disposing the welding electrode 13 at a distance from the work pieces to be welded or the work piece 12 to be welded. In order to get from the basic position to a welding position, in which the welding electrode contacts at least one of the work pieces 12 to be welded, it is provided that the tappet 11 performs a forward movement along a forward direction E.

[0033] Preferably the base plate 5 of the welding electrode unit 100 comprises a recess through which the tappet 11 passes or crosses during its forward movement. In this regard, the recess is preferably adapted to the tappet 11 with precise fit. In this way, guidance of the tappet 11 during its forward movement can be supported. In this regard, it is conceivable that the tappet 11 already projects out of the base plate 5, at least in part, in its basic position. By means of the forward movement, the extent of projection is supposed to be increased to such an extent that at the end of its forward movement, the welding electrode 13 enters into contact with the work piece 12 to be welded.

[0034] Furthermore, it is provided that the tappet 11 is connected with a repositioning device 2 by way of a pressure spring 8. Preferably, the pressure spring 8 is connected with the repositioning device 2 by way of an upper spring bolt 7, and with the tappet 11 by way of a lower spring bolt 9. In this regard, the repositioning device 2 comprises a housing 17, wherein the housing 17 has a lid region on its side facing away from the base plate 5, on the inside of which region the upper spring bolt 7 or the pressure spring 8 is attached. Preferably, the housing 17 encloses the pressure spring 8 in sleeve-like manner, wherein the housing 17 has an opening at a lower end, facing the base plate 5, from which opening the tappet 11 and/or the pressure spring 8 projects out of the housing 17.

[0035] It is furthermore provided that the repositioning device 2 can be driven to perform a forward movement, by way of a toggle lever mechanism 4. In this regard, the repositioning device 2 itself is coupled with a column guide 3, in such a manner that the column guide 3 determines the forward direction during the forward movement. Preferably, for this purpose, at least a part of the repositioning device 2, particularly a part of the housing 17, encompasses or encloses the column guide 3. The column guide 3 is preferably also attached to the base plate.

[0036] In FIGS. 2a and 2b, the welding electrode unit 100 of the first exemplary embodiment of the present invention is shown in two different side views, in a basic position. In this regard, in FIG. 2b, part of the housing 17 is not shown, in order to allow a view of the pressure spring 8. For the forward movement of the repositioning device 2 and thereby for the tappet 11, out of the basic position, it is provided that the toggle lever mechanism 4 translates a drive movement that runs essentially perpendicular to the forward direction or essentially perpendicular to the forward movement into the forward movement. In this way, the forward movement is controlled by way of the toggle lever mechanism 4.

[0037] The toggle lever mechanism 4 is preferably composed, in detail, of [0038] a first rocker 41 that can be pivoted about a first articulation axis A, and [0039] a second rocker 42 that can be pivoted about a second articulation axis B, wherein first and second rocker 41 and 42 are connected with one another in such a manner that the first rocker 41 can be pivoted, relative to the second rocker 42, about a third articulation axis C. In particular, the first and the second articulation axis A and B are disposed along a direction that runs parallel to the forward direction, wherein [0040] the first rocker 41 is articulated so as to pivot about the first articulation axis A, on the repositioning device 2 that can be moved along the forward direction, and [0041] the second rocker 42 is articulated on a locally fixed frame structure 15, about the second articulation axis B. In this way, it is possible that a distance between the first articulation axis A and the second articulation axis B can be varied, by means of a drive movement that runs essentially perpendicular to the forward direction, which movement is performed by the third articulation axis C, and thereby finally, the repositioning device 2 can be moved along the forward direction E. In the embodiment shown in FIG. 1, it is provided that the drive movement is introduced by means of a pneumatic cylinder 6. For a movement of the repositioning device 2 in the direction of the base plate 5, a piston of the pneumatic cylinder 6 is moved out, the first rocker 41 is pivoted clockwise, and the distance between the first articulation axis A and the second articulation axis B is increased. In this regard, the piston is preferably articulated on the first rocker 41 so as to pivot about a third articulation axis C. During the drive movement of the piston, the third articulation axis C moves, at least in part, on a circular path. In order to be able to bring about the pivoting movement of the first rocker A, it is therefore necessary that the piston follows this circular path during its drive movement, at least in part. For this purpose, the pneumatic cylinder 6 is preferably articulated on the base plate so as to pivot about a fourth articulation axis D, thereby causing the piston to adapt its inclination relative to the base plate 5 during its drive movement.

[0042] In FIGS. 3a and 3b, the welding electrode unit 100 according to the first exemplary embodiment of the invention is shown in two different side views, in the welding position. In the welding position, the forward movement has been terminated. The forward movement of repositioning device and thereby of the tappet 11 is preferably terminated as soon as the toggle joint mechanism 4 has been fully extended, i.e. the first, the second, and the third articulation axis A, B, and C are disposed along the direction that runs parallel to the forward direction E. In particular, the repositioning device 2 is locked in the welding position, preferably while the toggle lever mechanism 4 is fully extended, by means of the toggle lever mechanism 4.

[0043] As soon as the welding position has been reached, the forward movement controlled by the toggle lever mechanism 4 is terminated. A subsequent repositioning movement is particularly independent of the forward movement. A stored-energy means, which is formed by the pressure spring 8 in the first exemplary embodiment, ensures the repositioning movement required during the welding process. In this regard, it is provided that over the duration of the welding process, the welding electrode 13 acts on a weld 14 with an essentially constant force or with an essentially constant pressure. In this way, melting of the work piece 12 in the region of the weld 14, which occurs during a welding process for system reasons, is balanced out (in terms of path) by way of the repositioning movement brought about by the pressure spring 8. In this regard, the force that acts on the tappet 11 by means of the pressure spring 8 can be optionally adjusted using an adjustment screw 1, wherein a bias force can be adjusted or established by means of the adjustment screw 1, with which force the welding electrode 13 presses on the work piece 12.

[0044] In particular, the welding electrode unit 100 has a sensor means 10 for measuring energy, which means is preferably disposed between the lower spring bolt 9 and the tappet 11. In this way, the force effect of the welding electrode 13 on the work piece 12 can be advantageously controlled and, if necessary, corrected or optimized by means of the adjustment screw 1.

REFERENCE SYMBOL LIST

[0045] 1 adjustment screw [0046] 2 repositioning device [0047] 3 column guide [0048] 4 toggle lever mechanism [0049] 5 base plate [0050] 6 pneumatic cylinder [0051] 7 upper spring bolt [0052] 8 pressure spring [0053] 9 lower spring bolt [0054] 10 sensor means for energy measurement [0055] 11 tappet [0056] 12 work piece [0057] 13 welding electrode [0058] 14 weld [0059] 15 frame structure [0060] 16 cylinder axis [0061] 17 housing [0062] 18 adapter [0063] 41 first rocker [0064] 42 second rocker [0065] A first articulation axis [0066] B second articulation axis [0067] C third articulation axis [0068] D fourth articulation axis [0069] E forward direction