TORCH BODY FOR THERMAL JOINING

Abstract

The invention relates a torch body for thermal joining of at least one workpiece, in particular for arc welding or arc brazing, said torch body comprising a non-consumable electrode provided in the body, in particular a tungsten electrode, for generating an arc between the electrode and the workpiece. The torch body has an end nozzle, which is devoid of potential, for discharging a shielding gas flow from a gas outlet. A secondary flow channel is provided for dividing the shielding gas flow into a main gas flow and a secondary gas flow, the secondary gas flow annularly surrounding the main gas flow at the gas outlet.

Claims

1. A torch body (10) for thermally joining at least one workpiece (11) by arc welding or arc soldering, comprising: a non-consumable electrode (1) arranged in the torch body (10) for generating an arc between the electrode (1) and the workpiece (11), and an electrically potential-free front nozzle (3) defining a gas outlet (13) through which a shielding gas stream can flow out, the front nozzle (3) comprising a center nozzle (2), a gas nozzle (4), and at least one secondary flow channel (5) to divide the shielding gas stream into a main gas flow (14) and a secondary gas flow (15), wherein the secondary gas flow (15) surrounds the main gas flow (14) at the gas outlet (13) in an annular pattern.

2. The torch body (10) according to claim 1, wherein the front nozzle defines a longitudinal axis (20) and a circumference, and wherein several secondary flow channels (5) are arranged along the circumference of the front nozzle (3) at and are at an opening angle of 10 to 30 directed outwards relative to the longitudinal axis (20) of the front nozzle (3).

3. The torch body (10) according to claim 1, wherein the electrode (1) either forms a distal end (9) of the torch body (10) facing the workpiece (11) or is substantially flush with the distal end (9) of the torch body (10).

4. The torch body (10) according to claim 1, wherein the front nozzle (2) forms a distal end (9) of the torch body (10) facing the workpiece (11), and the electrode (1) is recessed relative to the distal end (9).

5. The torch body (10) according to claim 1, wherein the electrode (1) a substantially cylindrical section (21) and/or a sharpened end (22) facing the workpiece.

6. The torch body (10) according to claim 1, further comprising a cooling element (6) adapted to cool the torch body (10), wherein the cooling element (6) has cooling channels (12) for conveying a coolant.

7. The torch body (10) according to claim 1, wherein the front nozzle (3) is configured in two parts.

8. The torch body (10) according to claim 1, further comprising an internal electric isolator (8) adapted to electrically isolate the front nozzle (3) from the electrode (1).

9. The torch body (10) according to claim 1, wherein an annular gap (17) for equalizing and guiding the secondary gas flow (15) is formed between the center nozzle (2) and the gas nozzle (4).

10. The torch body (10) according to claim 1, wherein the at least one secondary flow channel (5) is formed in the center nozzle (2).

11. The torch body (10) according to claim 9, wherein the front nozzle (3) defines a longitudinal axis (20) and a circumference, and wherein the gas nozzle (4) at least partially overlaps the center nozzle (2) at the end of the outlet opening (16) of the at least one secondary flow channel (5) forming the annular gap (17) over the circumference.

12. (canceled)

13. (canceled)

14. The torch body (10) according to claim 1, wherein a ratio of the cross section of the outlet opening (7) to the sum of the cross sections of the secondary flow channels (5) is approximately 4:5.

15. The torch body (10) according to claim 1, wherein the gas nozzle (4) is configured as a fastening nut so that it can be coupled to the center nozzle (2).

16. A torch having a torch body (10) according to claim 1.

17. A method for thermally joining at least one workpiece (11), comprising: arc welding or arc soldering using a torch body (10) with a non-consumable electrode (1) for generating an arc between the electrode (1) and the workpiece (11), surrounding the electrode (1) with a shielding gas stream that flows out of a potential-free front nozzle (3) of the torch body, wherein the shielding gas stream is divided into a main gas flow (14) that directly surrounds the electrode (1) and a secondary gas flow (15) that exits from a front end (18) of the torch body (10), and wherein the secondary gas flow (15) surrounds the main gas flow (14) at the gas outlet (13) in an annular pattern.

18. A joining device (100) for thermally joining at least one workpiece (11) by arc welding or arc soldering, comprising: a machine-controlled torch (200) for generating an arc between a non-consumable electrode (1) arranged therein and the workpiece (11), a torch changing device (300) for replacing the torch (200) with a new torch (200), a tactile seam tracking system (900) having a position transducer (901) that is arranged so as to be movable relative to the workpiece (11) and so as to be at a certain distance from the torch (200), wherein the torch (200) is coupled to the tactile seam tracking system (900), so that movement relative to the position transducer (901) moves the torch (200) either into at least one working position (500) for thermally joining the workpiece (11) or into a replacement position (400) for replacing the torch (200) with a new torch (200).

19. The joining device (100) according to claim 18, further comprising a movable carriage (600) to which the torch (200) is coupled.

20. The joining device (100) according to claim 19, wherein the carriage (600) is powered electrically, pneumatically or hydraulically.

21. The joining device (100) according to claim 19 wherein the carriage (600) has a torch holder (601) for holding the torch (200) and one or both of either a coupling device (602) for feeding shielding gas and a coupling device (603) for feeding coolant and welding energy.

22. The joining device (100) according to claim 18, wherein the torch (200) is locked at least in the working position (500).

23. The joining device (100) according to, claim 18, wherein the torch (200) can be moved exclusively between the working position (500) and the replacement position (400), and vice versa.

24. The joining device (100) according to claim 18, wherein the seam tracking system (900) has an outlet opening (902) through which a filler material (700) for arc soldering or arc welding and/or additional shielding gas can be dispensed.

25. The joining device (100) according to claim 18, wherein a distal end (903) of the tactile seam tracking system (900) is positioned at or near a front end (201) of the torch (200).

Description

DESCRIPTION OF THE DRAWINGS

[0067] In this context, the following is shown, at times schematically:

[0068] FIG. 1 a torch body for thermally joining at least one workpiece, comprising a center nozzle and a gas nozzle;

[0069] FIG. 2 detailed views of the torch body in a top view (a), a side view (b) and as a cutaway drawing (c);

[0070] FIG. 3 detailed views of the center nozzle in a top view (a), a side view (b) and as a cutaway drawing (c);

[0071] FIG. 4 detailed views of the gas nozzle in a top view (a), a side view (b) and as a cutaway drawing (c);

[0072] FIG. 5a a schematic depiction of a joining device in the working position in a first side view;

[0073] FIG. 5b a schematic depiction of a joining device in the working position in another side view;

[0074] FIG. 6 a schematic depiction of the joining device in the replacement position; and

[0075] FIG. 7 a schematic depiction of the joining device with the torch removed.

DETAILED DESCRIPTION

[0076] For the sake of clarity, identical components or those having the same effect are provided with the same reference numerals in the figures shown below, making reference to an embodiment.

[0077] FIG. 1 shows a torch body 10 for thermally joining at least one workpiece 11, especially for arc welding or arc soldering, with a non-consumable electrode 1 arranged in the torch body 10, especially a tungsten electrode, for generating an arc between the electrode 1 and the workpiece 11.

[0078] In the present embodiment of the invention, the electrode 1 is approximately flush with the torch body 10, that is to say, it forms its front end 18 together with the other components of the torch body 10. Within the scope of the invention, it can also be provided for the electrode 1 to form the distal end 9 of the torch body 10 facing the workpiece 11 and for it to project beyond the other components of the torch body towards the front end 18. As an alternative, it would also be conceivable for at least part of a nozzle that forms the distal end 9 of the torch body 10 facing the workpiece 11 and for the electrode 1 to be recessed relative to this end 9, particularly by approximately 0.5 mm to 1.5 mm.

[0079] The electrode 1 can have an essentially cylindrical section 21 and/or a sharpened end 22 facing the workpiece.

[0080] As is shown in FIG. 1, a front nozzle 3 is provided that is electrically potential-disconnected or potential-free by means of an internal isolator 8 and that allows a shielding gas stream to flow out of a gas outlet 13 of the torch. The internal isolator 8 can be made, for example, of a ceramic material or it can contain ceramic material.

[0081] As can also be seen in FIG. 1, external isolation 19 is provided so that the parts of the torch that can be accessed by the user from the outside can be electrically isolated from the non-isolated components in the interior of the welding torch. Moreover, this external isolation 19 prevents the arc from drifting away from the electrode 1.

[0082] The front nozzle 3 has at least one secondary flow channel 5 to divide the shielding gas stream into a main gas flow 14 and into secondary gas flow 15. Moreover, the secondary gas flow 15 surrounds the main gas flow 14 at the gas outlet 13 in an annular pattern. The shielding gas can contain argon or helium or else a mixture of both as its main component. In addition, small admixtures of oxygen, carbon dioxide and/or hydrogen are possible as secondary constituents.

[0083] As can be gleaned from FIG. 1 as well as FIGS. 2a to 2c and 3a to 3c, several secondary flow channels 5 are arranged along the circumference of the front nozzle 3, preferably at an opening angle of 10 to 30 directed outwards relative to the longitudinal axis 20 of the front nozzle 3.

[0084] FIG. 1 shows a cooling element 6 for cooling the torch body 10 that, in this case, has cooling channels 12 to convey a coolant. It can also be provided that a portion of the shielding gas stream is passed through these channels 12 in order to cool the torch body 10.

[0085] FIGS. 1 and 2 show that the front nozzle 3 in the present embodiment is configured in two parts and it comprises a center nozzle 2 and a gas nozzle 4. As set forth in the invention, it is also conceivable for the front nozzle 3 to be configured in one piece.

[0086] FIGS. 3a to 3c show detailed views of the center nozzle 2. FIG. 3a shows a top view, FIG. 3b shows a side view and FIG. 3c shows a cutaway view of the center nozzle 2. The main gas flow 14 of the shielding gas stream exits through an internal outlet opening 7 of the center nozzle 2.

[0087] FIGS. 4a to 4c show analogous views of the gas nozzle 4.

[0088] An annular gap 17 for equalizing and guiding the secondary gas flow is formed between the center nozzle 2 and the gas nozzle 4. As can be seen in FIGS. 2a to 2c, the gas nozzle 4 overlaps the center nozzle 2 at the end of the external outlet opening 16 of the secondary flow channels 5 in order to form the annular gap 17 along the circumference, at least partially.

[0089] The shielding gas exits from the annular gap 17 at the center nozzle 2. The secondary flow channels 5 open up into the outer outlet openings 16. The center nozzle 2 has an annular surface 23 so that the center nozzle 2 can be secured with a positive fit in the axial direction on the torch body 10. The annular surface 23 can be additionally provided with spanner flats to facilitate the removal from the conical press fit of the torch body. The individual discrete secondary flow channels 5 open up into the annular gap 17 approximately at the height of the annular surface 23 and exit from it in the direction of the workpiece 11.

[0090] The center nozzle 2 can be made of copper or of a copper alloy and/or the gas nozzle 4 can be made of brass or of a brass alloy.

[0091] It can also be gleaned from FIGS. 4a to 4c that the gas nozzle 4 can be configured as a fastening nut so that it can be coupled to the center nozzle 2. Consequently, the center nozzle 2 fulfills a dual function in that, on the one hand, together with the gas nozzle 4, it forms the annular gap 17 and, on the other hand, it serves as a fastening means during the installation of the torch body 10 in order to fasten the center nozzle 2 to the torch body 10. Within the scope of this fastening, the gas nozzle 4 is pulled over the center nozzle 2 until an internal thread 24 of the gas nozzle 4 engages with an external thread 25 of the torch body 10. The annular surface 23 forms a stop of the center nozzle 2 against which the gas nozzle 4 exerts a force in the direction of the torch body 10 when the nozzles are being screwed in place.

[0092] The outlet opening 7 of the center nozzle 2 can have a diameter of approximately 13 mm.sup.2 to 20 mm.sup.2, especially about 16 mm.sup.2. The sum of the cross sections of the secondary flow channels 5 of the gas nozzle 4 can amount to approximately 18 mm.sup.2 to 22 mm.sup.2, especially about 20 mm.sup.2. In the present example, for instance, eight secondary flow channels 5 are provided, although this number can vary.

[0093] In order to ensure a particularly advantageous distribution of the shielding gas, the ratio of the diameter of the outlet opening 7 to the sum of the cross sections of the secondary flow channels 5 can be similar, especially about 4:5.

[0094] FIGS. 5a to 7 show a joining device 100 with a machine-controlled torch 200, 200 having, for example, a torch body 10 as described above, for generating an arc between a non-consumable electrode 1 arranged therein, especially a tungsten electrode, and the workpiece 11.

[0095] A torch changing device 300 is provided for replacing the torch 200 with a new torch 200. In this context, a replaceable torch 200 can have a replacement interface.

[0096] A tactile seam tracking system 900 has a position transducer 901 which is arranged at a certain distance from the torch 200 and so as to be movable relative to the workpiece 11. The position transducer 901 ascertains the momentary position of a measuring sensor installed on the front end of the position transducer 901, said measuring sensor moving along the joining site of the workpieces 11 that are to be joined together.

[0097] Within the scope of a movement relative to the position transducer 901, the torch 200 can be moved into at least one working position 500 for thermally joining the workpiece 111 and into a replacement position 400 for replacing the torch 200 that is to be replaced by a new torch 200.

[0098] As FIG. 1 also shows, due to the structural dimensions of the thermal joining device 100, a distal end 903 of the position transducer 901, which normally is configured so as not to be movable, is arranged very close to, that is to say, just a few millimeters away from, the front end 201 of the torch 200. For this reason, the torch 200, 200 and the position transducer 901 might collide when the torch is being replaced.

[0099] The position transducer 901 can have a feed device 904 with an outlet opening 902 through which a filler material 700 for welding or soldering can be moved into the immediate vicinity of the torch head. The filler material 700 can be, for instance, welding wire or soldering wire. The wire can be fed potential-free as a cold wire or non-isolated as a hot wire.

[0100] Consequently, during the replacement of a torch, the torch 200, 200 and the filler material 700 might collide, for instance, due to a filler wire that has not been retracted completely. Such collisions can damage the torch 200.

[0101] Therefore, the tactile seam tracking system 900 fulfills a dual function. On the one hand, it has the position transducer 901 to ascertain the momentary position of the torch 200 relative to the seam that is to be welded or soldered. On the other hand, the seam tracking system 900 also comprises the feed device 904 that serves to feed the filler material.

[0102] FIG. 5a shows the joining device in a side view, FIG. 5b shows another side view. In the working position 500 depicted in both FIGS. 5a and 5b, the tactile seam tracking system 900 moves along a seam that is to be welded or soldered. The torch 200 moves at a small distance or in the same position thereto and follows the seam tracking system 900, thus defining a prescribed working direction of the torch 200.

[0103] In the replacement position 400 as shown in FIGS. 6 and 7, the distance between the torch 200 and the seam tracking system 900 is increased, particularly along the working direction, in that the torch 200 is moved away from the tactile seam tracking system 900 and counter to the working direction.

[0104] Once the distance between the torch 200 and the tactile seam tracking system 900 has increased, the torch 200 that is to be changed can be removed and replaced by a new torch 200. FIG. 7 shows the device 100 with the removed torch 200, 200. Means are provided such as, for instance, the gripper arms of a robot, so that the spent torch 200 that is to be replaced can be uncoupled from the source of welding energy, especially from the lines for the shielding gas, for the electric energy and for the coolant. Then the torch 200 is moved away from the tactile seam tracking system 900, for example, approximately in parallel to the longitudinal direction of the torch 200 towards a changer (not shown here), so that it can ultimately be removed without colliding with the seam tracking system 900.

[0105] In order to achieve the requisite distance between the torch 200 and the tactile seam tracking system 900, a movable carriage 600 for positioning the torch that has been coupled to the carriage can be provided in order to replace the torch 200 that is to be replaced with a new torch 200. Such a torch is shown in FIGS. 5a to 7. In order to prevent the torch 200 and the feed device 904 from colliding, the torch 200 is moved by means of the carriage 600 in the direction of the changer and thus away from the feed device 904. The carriage 600 is necessary since the feed device 904 for the filler material 700 and the measuring sensor of the tactile seam tracking system 900 are arranged rigidly, that is to say, immovably, relative to the torch 200, so that this feed device 904 gets in the way during the procedure of replacing the torch 200 and, due to the very small distance to the torch 200, it might cause the torch 200 to collide and be damaged.

[0106] The carriage 600 can be powered electrically, pneumatically or hydraulically.

[0107] The carriage 600 has a torch holder 601 for holding the torch 200 and/or a coupling device 602 for coupling the line that conveys the shielding gas through the torch body 10 and/or a coupling device 603 for coupling the lines that convey the coolant and the welding energy as a so-called current-water cable through the torch body 10. The torch holder 601 ensures easy latching and unlatching, so that the replacement of the torch 200, 200 can be carried out quickly and reliably.

[0108] The torch 200 can be moved between the working position 500 and the replacement position 400 and vice versa. It would also be possible for the torch 200 to be moved exclusively between these two positions. In order to attain a very high degree of precision of the welding or soldering processes, the control means has to allow the appertaining positions of the torch to be approached very precisely. In order to prevent imprecisions, the torch 200 can be locked at least in the working position 500 and/or in the replacement position 400.

LIST OF REFERENCE NUMERALS

[0109] 1 electrode [0110] 2 center nozzle [0111] 3 front nozzle [0112] 4 gas nozzle [0113] 5 secondary flow channel [0114] 6 cooling element [0115] 7 inner outlet opening [0116] 8 internal isolator [0117] 9 distal end [0118] 10 torch body [0119] 11 workpiece [0120] 12 cooling channels [0121] 13 gas outlet [0122] 14 main gas flow [0123] 15 secondary gas flow [0124] 16 outer outlet opening [0125] 17 annular gap [0126] 18 front end of the torch body [0127] 19 external isolation [0128] 20 longitudinal axis of the front nozzle [0129] 21 cylindrical section of the electrode [0130] 22 sharpened end of the electrode [0131] 23 annular surface [0132] 24 internal thread of the gas nozzle [0133] 25 external thread of the torch body [0134] 26 truncated cone plateau of the electrode [0135] 100 joining device [0136] 200 torch [0137] 200 torch [0138] 201 front end of the torch [0139] 300 torch changing device [0140] 400 replacement position [0141] 500 working position [0142] 600 carriage [0143] 601 torch holder [0144] 602 coupling device for the shielding gas [0145] 603 coupling device for the coolant and for the welding energy [0146] 700 filler material [0147] 900 tactile seam guiding device [0148] 901 position transducer [0149] 902 outlet opening [0150] 903 distal end [0151] 904 feed device