WELDING TORCH COMPRISING A DEVICE FOR FEEDING A CONSUMABLE WELDING WIRE TOWARDS THE TOOL CENTER POINT

Abstract

A welding torch includes a torch body and at least one device for feeding a consumable welding wire towards the tool center point that has an attachment device for attachment to the torch or an element connected thereto. A base support, which is connected to the attachment device, includes at least two deflection elements for guiding the wire towards the center point. The at least two deflection elements are arranged on the base support so that a first wire path length from the last deflection element located closest to the center point to the center point is shorter than a second wire path length between the last deflection element and a further deflection element as viewed counter to a main wire feed direction, and so that the arcuate wire has a greater segment height along the second path length than the segment height along the first path length.

Claims

1. A welding torch (3), in particular a TIG welding torch, comprising a torch body (3′) and at least one device (1) for feeding a consumable welding wire (2) towards the tool center point (TCP), wherein at least one feed device (1) has an attachment means (6) for attachment to the welding torch (3) or an element connected thereto, comprising a base support (5), which is connected to the attachment means (6) and comprises at least two deflection elements (9, 9′) for guiding the welding wire (2) towards the tool center point (TCP), wherein the at least two deflection elements (9, 9′) are arranged on the base support (5) in such a way that a first path length (l.sub.1) of the welding wire (2) from the last deflection element (9′) located closest to the tool center point (TCP) to the tool center point (TCP) is shorter than a second path length (12) of the welding wire (2) between the last deflection element (9′) and a further deflection element (9) as viewed counter to a main feed direction (F) of the welding wire (2), and wherein the at least two deflection elements (9, 9′) are further arranged on the base support (5) in such a way that the welding wire (2), which runs arcuately, has a greater segment height (h2) along the second path length (l.sub.2) than the segment height (h1) along the first path length (l.sub.1).

2. The welding torch (3) according to claim 1, wherein at least one deflection element (9, 9′), preferably the last deflection element (9′), is adjustable in a direction essentially transversely to the base support (5).

3. The welding torch (3) according to claim 1, wherein in addition to the last deflection element (9′), at least two deflection elements (9) are provided, between which the welding wire (2) can be guided.

4. The welding torch (3) according to claim 1, wherein the position of at least one deflection element (9, 9′) can be changed relative to the base support (5), so that the feed angle (α) of the welding wire (2) towards the tool center point (TCP) can be changed with essentially constant tool center point (TCP).

5. The welding torch (3) according to claim 4, wherein the position of at least one deflection element (9, 9′) can be changed in that different base supports (5) are provided, which in each case comprise at least two deflection elements (9, 9′) for attaining different feed angles (α).

6. The welding torch (3) according to claim 4, wherein the position of at least one deflection element (9, 9′) can be changed in that at least one deflection element (9) is arranged on a roller support (14), which roller support (14) is adjustably connected to the base support (5).

7. The welding torch (3) according to claim 6, wherein the roller support (14) is adjustable continuously relative to the base support (5) along an arcuate slotted guide path (x).

8. The welding torch (3) according to claim 6, wherein the roller support (14) can be connected to the base support (5) in several different positions.

9. The welding torch (3) according to claim 1, wherein the last deflection element (9′) is arranged on a pin support (12), which is preferably connected adjustably to the base support (5).

10. The welding torch (3) according to claim 9, wherein the position of at least one deflection element (9, 9′) can be changed in that the deflection elements (9) arranged on the roller support (14) and the last deflection element (9′) arranged on the pin support (12) are arranged coupled to one another so as to be capable of being adjusted with respect to the base support (5).

11. The welding torch (3) according to claim 1, wherein at least one deflection element (9), in particular the last deflection element (9′), is formed by means of at least one sliding pin (10), which is preferably mounted in a rotatable manner.

12. The welding torch (3) according to claim 1, wherein at least one deflection element (9) is formed by means of at least one roller (7).

13. The welding torch (3) according to claim 11, wherein at least one sliding pin (10) has a groove (11) for the welding wire (2) and/or at least one roller (7) has a groove (8) for the welding wire (2), respectively.

14. The welding torch (3) according to claim 1, wherein the attachment means (6) is formed for the releasable and preferably rotatable connection to the welding torch (3) or to an element connected thereto.

Description

[0025] FIG. 1 shows a welding torch comprising a feed device attached thereto according to an exemplary embodiment in the case of an acute feed angle;

[0026] FIG. 2 shows the welding torch comprising the feed device according to FIG. 1 in the case of correspondingly adjusted deflection elements for attaining a greater feed angle;

[0027] FIG. 3 shows a welding torch comprising a different exemplary embodiment of a feed device attached thereto comprising adjustable deflection elements;

[0028] FIG. 4 shows a different view onto the welding torch comprising the feed device according to FIG. 3;

[0029] FIG. 5 shows a welding torch comprising a further exemplary embodiment of a feed device comprising adjustable deflection elements in the case of an acute feed angle;

[0030] FIG. 6 shows a different view onto the welding torch comprising the feed device according to FIG. 5;

[0031] FIG. 7 shows the welding torch comprising the feed device according to FIG. 5 in the case of adjusted deflection elements for attaining an obtuse feed angle;

[0032] FIG. 8 shows a different view onto the welding torch comprising the feed device according to FIG. 7;

[0033] FIG. 9A shows a view onto the welding torch comprising a feed device attached thereto according to FIGS. 7 and 8 from the front; and

[0034] FIG. 9B shows a view onto the welding torch comprising a feed device attached thereto according to FIGS. 7 and 8 from the front with a feed device, which is arranged so as to be rotated compared to FIG. 9A.

[0035] FIG. 1 shows a welding torch 3 comprising a feed device 1 attached thereto for feeding a consumable welding wire 2 towards the tool center point TCP according to a simple exemplary embodiment. The TCP can be part of a melting zone of the welding torch 3, wherein the melting zone is that zone, which is able to operationally consume the welding wire 2, which is fed to this zone, or the free end thereof, respectively, in a melting point of the path for the welding torch 2. In this case, a feed angle α of the welding wire 2 to the TCP, which is that angle, which the central axis a of the welding torch 3, thus in the case of a welding torch 3 comprising a non-consumable electrode 4, the longitudinal axis of the non-consumable electrode 4, draws with the longitudinal direction b of the consumable welding wire 2, is preferably an acute angle. Depending on the application, the feed angle α can be up to 180°. The longitudinal direction b of the consumable welding wire 2 is determined by the tangent to the welding wire 2 in the TCP. The welding torch 3 is in particular a TIG welding torch comprising a tungsten electrode as non-consumable electrode 4. However, laser welding torches or combined laser-arc welding torches as well as plasma torches and torches comprising a flame are also conceivable (not illustrated). In the event that the energy for a welding process is not supplied by an arc but, for example, by a laser, the feed angle or angle of attack, respectively, of the welding wire is to be understood as the angle occurring in the TCP or melting point, respectively, between the welding wire or a path for the welding wire, respectively, and the central alignment of the energy flow in the melting zone of the welding torch.

[0036] The feed device 1 includes an attachment means 6 for attachment to the welding torch 3 or to an element connected thereto. A base support 5 comprising at least two deflection elements 9, 9′ for guiding the consumable melting wire 2 is connected to the attachment means 6. In the illustrated exemplary embodiment, the attachment means 6 is formed by means of a clamp, which encompasses the welding torch 3 and which surrounds the torch body 3′. Two rollers 7 are arranged on the base support 5 as deflection elements 9 for guiding the welding wire 2, and a deflection element 9′ formed as sliding pin 10, which is last or which is closest to the TCP, respectively, are arranged on the base support 5. As will be described further below, the deflection elements 9, 9′ can also be arranged indirectly and possibly adjustably on the base support 5 via further elements. The sliding pin 10 can have an external thread and can thus be adjusted essentially perpendicularly to that plane, in which the welding wire 2 lies along the second path length l.sub.2, whereby the welding wire 2 can be positioned exactly in the melting zone. Further rollers 15 or deflection elements for guiding the welding wire 2 can furthermore be arranged on the base support 5. In order to keep the friction during the feeding of the welding wire 2 as low as possible, the rollers 7, 15 and possibly the sliding pin 10 are rotatably mounted. To guide the welding wire 2, the rollers 7, 15 can have grooves 8. The sliding pin 10 can also be formed with a groove 11. Even if a movement of the welding wire 2 away from the TCP is possible at times, the welding wire 2 is generally fed towards the tool center point TCP during the welding process and is melted there to form a welding seam between two workpieces or to form a coating on a workpiece (not illustrated). The feed direction of the welding wire 2 towards the tool center point TCP is identified as main feed direction F.

[0037] The deflection elements 9 formed by the rollers 7 and the last deflection element 9′ formed by the sliding pin 10 are arranged on the base support 5 so that the welding wire is deflected at three points in such a way that a first path length l.sub.1 of the welding wire 2 from the last deflection element 9′ located closest to the tool center point TCP to the tool center point TCP is shorter than a second path length l.sub.2 of the welding wire 2 between the last deflection element 9′ and a further deflection element 9 as viewed counter to the main feed direction F of the welding wire 2. By means of a corresponding arrangement of the at least two deflection elements 9, 9′ on the base support 5, the welding wire 2 has a greater segment height h.sub.2 along the second path length l.sub.2 than the segment height h.sub.1 of the first path length l.sub.1. Along the path length 12, the welding wire 2 has an essentially stronger or equal curvature than along the path length l.sub.1.

[0038] In the case of an essentially constant TCP, the feed angle α of the welding wire 2 towards the tool center point TCP is advantageously adjustable. For this purpose, the deflection elements 9, 9′ can be arranged on or towards the base support 5, respectively, so as to be capable of being adjusted in their position. The position of at least one deflection element 9, 9′ can, for example, be changed in that different base supports 5 are provided, which in each case comprise at least two deflection elements 9, 9′, for attaining different groups of positions of the deflection elements 9, 9′ and thus different feed angles α, which can be selected and assembled, as required. Such an adjustability of the deflection elements 9, 9′ can also be attained in that, for example, deformable materials are used as deflection elements 9, 9′.

[0039] FIG. 2 shows the welding torch 3 comprising the feed device 1 according to FIG. 1 comprising a different base support 5, by means of which other positions of the deflection elements 9, 9′ and a greater feed angle α result. Due to the changed positions of the deflection elements 9, 9′, the path lengths 11, 12 and the segment heights h.sub.1, h.sub.2 and the feed angle α change as well, but the TCP is essentially maintained in this case.

[0040] FIG. 3 shows a welding torch 3 comprising a different exemplary embodiment of a feed device 1 attached thereto comprising adjustably arranged deflection elements 9, 9′. The two deflection elements 9, which are formed as rollers 7, are thereby attached to a roller support 14, which is arranged adjustably with respect to the base support 5, whereby different feed angles α of the welding wire 2 can be attained. The roller support 14 can be adjusted continuously along an arcuate slotted guide path x with respect to the base support 5. The adjustment of the feed angle α can take place in a particularly simple and quick way via a corresponding actuating element 13, whereby the roller support 14 comprising the rollers 7 and possibly further rollers 15 is moved along the accurate slotted guide path x with respect to the base support 5. The last deflection element 9′ is attached to a pin support 12, which is connected accordingly to the base support 5. In response to movement of the roller support 14 with respect to the base support 5 along the accurate slotted guide path x, a change to the feed angle α of the consumable welding wire 2 towards the TCP results without essential change to the TCP. The first path length l.sub.1 and the second path length l.sub.2 and the first segment height h.sub.1 and the second segment height h.sub.2 are thus changed accordingly, so that the feed angle α changes. The roller support 14 can be fixed in the desired position on the base support 5 via corresponding screws or the like.

[0041] FIG. 4 shows a different view onto the welding torch 3 comprising the feed device 1 according to FIG. 3. Markings 17, which display the corresponding adjustment of the roller support 14 with respect to the base support 5 for a desired feed angle α, are thereby visible on the base support 5.

[0042] FIG. 5 shows a welding torch 3 comprising a further exemplary embodiment of a device 1 attached thereto for feeding a consumable welding wire 2 towards the tool center point TCP. In this case, the feed angle α of the welding wire 2 is an acute angle. For the simple and quick adjustment of the feed angle α of the welding wire 2 towards the tool center point TCP with essentially constant TCP, the deflection elements 9 formed as rollers 7 are arranged on a roller support 14, which is adjustably connected to the base support 5. The last deflection element 9′, which is formed as sliding pin 10, on the pin support 12 is also connected to the roller support 14 in a movably coupled manner. The roller support 14 can be adjusted continuously with respect to the base support 5 along an arcuate slotted guide path x. The adjustment of the feed angle α can take place in a particularly simple and quick way via a corresponding actuating element 13, whereby the roller support 14 comprising the rollers 7 and possibly further rollers 15 is moved along the arcuate slotted guide path x with respect to the base support 5. The movement of the last deflection element 9′ also takes place in a coupled manner with the movement of the roller support 14. The positions of the deflection elements 9, 9′ are thus changed accordingly, so that the feed angle α changes.

[0043] FIG. 6 shows a different view onto the welding torch 3 comprising the feed device 1 attached thereto for the welding wire 2 according to FIG. 5 in the case of an acute feed angle α. The last deflection element 9′ can be adjusted essentially transversely to the base support 5, i.e. at a right angle to that plane, in which the welding wire 2 lies along the second path length l.sub.2, via an actuating element 16. The base support 5 can also be adjustably arranged in the longitudinal direction L of the welding torch 3.

[0044] FIGS. 7 and 8 show the welding torch comprising the feed device 1 according to FIGS. 5 and 6 in the case of correspondingly adjusted deflection elements 9, 9′ to attain an obtuse feed angle α.

[0045] FIG. 9A shows a view onto a welding torch 3 comprising the feed device 1 from the front. The attachment means 6 is thereby formed for the rotatable connection to the welding torch 3. According to the desired welding task, the feed device 1 can thus be attached to the welding torch 3 or torch body 3′, respectively, in a position, which is suitable for the welder. FIG. 9B shows a view onto the welding torch 3 comprising the feed device 1 from the front in a position, which is rotated compared to FIG. 9A.

[0046] It applies for the embodiments according to the preceding FIGS. 3 to 9B that the roller support 14 and the pin support 12 can be adjusted in a coupled manner and that this takes place by means of elongated holes and journals. Roller supports 14 and pin supports 12 are arranged displaceably and are embodied adjustably, so that the deflection elements 9 and 9′ are kinematically coupled by means of a control element. The control element can be embodied, for example, as a journal moving along the arcuate slotted guide path x or also as articulated rod.

[0047] In summary, it applies that the deflection element 9 as well as the last deflection element 9′ have at least one so-called support point. When the deflection element 9 has a groove, comprising a, for example, V-shaped or U-shaped cross section, two and more support points result for each deflection element 9—but to be functionally considered to be one support point. In one support point, the welding wire 2 operationally contacts one deflection element. In the case of the (functional) support point of deflection element 9 or of one of the deflection elements 9, the greatest bending moment occurs operationally in the welding wire 2. A support point is to thus be understood essentially as contact point of welding wire 2 and deflection element 9, 9′, due to which low feed forces result in an advantageous manner, with which the welding wire 2 is bent into the melting zone. As a function of its properties, such as, for example, thickness, material, or its pre-bending, respectively, the welding wire 2 can be guided by different numbers of support points of a deflection element 9, 9′. A path length l.sub.1 or 12, respectively, is that part, along which the welding wire 2 is moved in the main feed direction F, and, in the case of path length l.sub.1, is limited by the tool center point TCP and the last support point of the last deflection element 9′ located closest to the TCP, or, in the case of the path length l.sub.2, respectively, is limited by the last support point and the support point of the further deflection element 9 or the deflection element 9 located behind it, respectively, as viewed counter to the main feed direction F, advantageously by means of that one of the support points, at which operationally the greatest bending moment occurs in the welding wire 2. The path lengths 11 and 12 are to thus be understood as part of a path, along which the welding wire 2 is operationally fed, wherein the path is to essentially be understood as curve. The length of a path length is to thus be understood as curve length. Depending on the arrangement of the deflection elements 9, 9′, a shape of the path results, which can be designed freely accordingly. With regard to the segment heights h.sub.1 and h.sub.2, and analogously to a circular arc, the segment height is to be understood as greatest normal distance between the straight line, which goes through the two end points of the path length, and a point on the path length, wherein the path length, viewed as curve, virtually overlaps with the center points of the cross sections of the welding wire 2. The segment height is to be seen as the greatest bulge of a path length, wherein the greatest bulge of the path length l.sub.2 in practice lies in a range of greater than 2 mm, in particular between 2 mm and 60 mm. In turn, a space around the point with the greatest bulge of the path length l.sub.2 represents a space for movement for the welding wire 2. Due to the fact that the required feed force for the welding wire 2 generally increases with the number of the support points, it is particularly advantageous to arrange such a space for movement for the welding wire on the path length l.sub.2, so that the welding wire 2 can bulge inside this space for movement, sometimes more or sometimes less, as required. It is advantageous when the space for movement is arranged at the point of the maximum bulge of the second path length 12 and when the space for movement extends essentially in the direction of and in the opposite direction of the maximum bulge of the second path length l.sub.2, and is more than 3 mm, in particular more than 5 mm, in total. Such a space for movement for the welding wire can also be provided when the welding wire contacts the bending element approximately in a resilient or displaceable support point.

[0048] The tool center point TCP preferably lies in the region of the melting zone of the welding torch. This melting zone is that region of the welding torch, which is able to consume the fed welding wire.

[0049] The present invention shows a welding torch 3, in particular a TIG welding torch, comprising at least one feed device 1 for feeding a consumable welding wire 2 towards the tool center point TCP of the welding torch 3, which allows for an optimal and friction-free feeding.