Title of Invention	"A DEVICE FOR WELDING TOGETHER CYLINDER PARTS AND ROTARY ELEMENTS"
Abstract	A device for welding together cylindrical parts and rotary elements, wherein an axially displaceable electrode shaft(1) is provided in a rotatably seated pipe shaft(8) . The pipe shaft (8) can be rotated with respect to the electrode shaft(1) and a connecting head(4) is provided on one end of the pipe shaft(8), which is equipped with gripper elements(5) for an interchangeable protective chamber(3). Gripper and positioning elements for a fastening cassette(31) provided for the parts(A,B) to be welded together, which is also interchangeable, are arranged in the protective chamber(3). The electrode shaft(l) extends through the connecting head(4) into the protective chamber(3).

Title of Invention

"A DEVICE FOR WELDING TOGETHER CYLINDER PARTS AND ROTARY ELEMENTS"

Abstract

A device for welding together cylindrical parts and rotary elements, wherein an axially displaceable electrode shaft(1) is provided in a rotatably seated pipe shaft(8) . The pipe shaft (8) can be rotated with respect to the electrode shaft(1) and a connecting head(4) is provided on one end of the pipe shaft(8), which is equipped with gripper elements(5) for an interchangeable protective chamber(3). Gripper and positioning elements for a fastening cassette(31) provided for the parts(A,B) to be welded together, which is also interchangeable, are arranged in the protective chamber(3). The electrode shaft(l) extends through the connecting head(4) into the protective chamber(3).

Full Text	The invention relates to a device for welding together cylindrical parts and rotary elements, comprising an electrode shaft, positioning and fastening means for the elements to be welded together and a hollow shaft surrounding the electrode shaft. When cylindrical workpieces are welded, the contact surfaces generally have one of two types of shape. With cylindrical parts cut perpendicularly to the longitudinal axis, the ends meet and the abutting surface forms a circle. With this type of attachment by welding, a rotary friction welding process is involved, which is easily mechanized. When the cylinders meet at an angle, however, the abutting surface forms a geometrical shape which is dependent on the diameters of the cylinders and the angle at which the centrelines of the cylinders meet. When there are several such cylinders branching off from a main cylinder, as in the case of pipe manifolds, and especially if they are close together, conventional welding from the outside becomes difficult. Such arrangements may be found, for example, in multiway valves, filter bodies, pipe junctions and similar components. When pipe junctions are welded, especially T-junctions, the limited height of the rabbet in the base cylinder and the size of conventional welding nozzles cause frequent problems. The above mentioned problems can be eliminated by approaching the welding position from the inside of the junction cylinder. Then the limited height of the rabbet or a second junction in the 2 vicinity on the outside no longer constitute obstacles. The welding nozzle is at the height of the seam, while the workpiece (or the welding nozzle) turns around its own axis. A second area of problems is constituted by long workpieces, whose rotation cannot be simply provided. A typical example of this is if distribution chambers are to be made from a pipe, wherein several pipe junctions are attached to a long pipe. The coaxial alignment of the cylinders in respect to each other is of extreme importance. To assure the quality of the weld seam, it is necessary to protect the workpieces to be welded together from the oxygen in the air by enclosing the workpieces in a chamber filled with a protective gas. In order to minimize the amount of the protective gas and the fill time, the chamber must be as small as possible. However, the small size of the chamber in turn causes problems when inserting the workpiece in the holder located in the chamber. Because of the small size of the chamber it is not possible to simultaneously work with one' s hands in the chamber and to look into the chamber. The object of the invention is based on providing a device by means of which the above described problems can be removed and the consumption of protective gas in particular can be reduced, even if the size of the workpieces to be welded together varies. This object is attained by means of the characteristics recited in the following eat claim 1. Advantageous embodiments of the invention are recited in the dependent claims. An exemplary embodiment of the invention will be explained in greater detail in what follows, with reference to the accompanying drawings. - 3 - Fig. 1 represents a device in accordance with the invention viewed from the side, wherein the portion above the centerline is shown in longitudinal section. Fig. 2 shows in greater detail an example of the protective chamber as provided in a device in accordance with Fig. 1, and of the fastening cassette housed in the protective chamber and intended for the workpieces to be welded together, and Fig.3 schematically represents a combination of the protective chamber and the fastening cassette corresponding to Fig. 2, viewed from the front, i.e. in the axial direction of the device. Part of the device represented in Fig. 1 is a pipe shaft 8 which is seated rotatably in respect to the frame 12 in bearings 10. The support shaft 1 of the welding electrode 2 is a long shaft, which extends through the pipe shaft 8 concentrically in respect to the pipe shaft 8. An insulation material pipe 9, which is used as the bearing between these elements, is provided between the electrode shaft 1 and the pipe shaft 8. Thus, the electrode shaft 1 and the pipe shaft 8 are rotatable in respect to each other, and the electrode shaft 1 can moreover be moved in the axial direction. The pipe shaft 8 is surrounded by a sleeve elements 6, which turns along with it, in which protective gas channels 7 are formed and which terminates at a widening forming a connecting head 4. The sleeve 6 extends over only a portion of the length of the pipe shaft 8. Next to the connecting head 4, the sleeve 6 is enclosed by a non rotatable frame sleeve 11 with the function of a structural housing which is fastened on the frame 12 to - 4 - prevent the rotation of the latter. This frame sleeve 11 with the function of a structural housing has the required connectors for the protective gas, the cooling gas and the compressed air required for the closing cylinder of the protective chamber 3. Rotatable connectors for providing the required gas connections to the channels 7 provided in the sleeve 6 and which end at the connecting head 4 are located between the sleeves 6 and 11. Only one channel 7 is represented in Pig. 1, but there are of course several of these, which are suitably distributed on the circumference of the sleeve 11 and of the connecting head 4. A threaded bushing 5 with an interior thread is provided on the connecting head 4, to which the protective chamber 3 can be connected by means of a threaded connector. The positioning and fastening means inform of fastening cassette 31 for the parts A, B to be welded together are fastened on the threaded bushing 5 of the connecting head 4. This is only schematically indicated in Fig.l. An exemplary embodiment is shown more detailed in Fig. 2, wherein the bottom section 32 of the protective chamber 3 is provided with a projecting neck 38, which is surrounded by a threaded sleeve 37, by means of which the chamber 3 can be fastened on the threaded bushing 5. The upper section 33 of the chamber 3 can be closed by means of the rod 35 of the piston of a cylinder 34. The upper section 33 is guided on vertical guides 48, whose upper ends are fastened on the cylinder 34. By means of seals 36 it is assured that the closed chamber 3 is tight. - 5 - The fastening cassette 31 intended for the workpieces to be welded together is pushed into the chamber 3, guided by guides 39 located on the bottom of the chamber. The guides 39 extend parallel with the axial direction of the electrode shaft 1, wherein the cassette slides in the axial direction of the electrode shaft into its intended position. Grooves 40 for the guides 39 are formed at the edges of the bottom of the positioning and fastening means inform of fastening cassette 31. The workpieces to be welded together are correctly positioned in respect to the welding electrode 2. A stop 41, which can be fixed in place or axially adjustable, is provided at the end of the guides 39 for the axial positioning taking place in the axial direction. A spring loaded pressure element 50 is arranged on the ceilling of the chamber which, when the upper section of the chamber has been lowered, meets the rear edge of the positioning and fastening means inform of fastening cassette 31, its upper and rear side, keeping the positioning and fastening means inform of fastening cassette 31 fixed in its place. In the case represented, arms 42, which can be pivoted around a hinge shaft with an axle 43, are a part of the positioning and fastening means inform of fastening cassette 31, which arms have a spring loaded arresting element 45 at their ends, which grasps the cassette behind the upper edge of its front 46. Sleeves 44 project from the arresting element 45, which sleeves contain springs which have been pressed between the bottom of the sleeve 44 and the ends of the arms 42. If the arresting element 45 in - 6 - Fig.2 is pulled to the right against the force of the springs, the arms 42 can be pivoted upward around the hinge shaft with an axle 43. The workpieces to be welded are placed into the cassette 31 while it is outside of the chamber 3. There are typically two cassettes 31 per chamber 3 so that, while a first cassette 31 is in the chamber 3, the other cassette 31 can be filled with parts to be welded. A regulating screw 47 determines the position of the parts, and the downward pivoted arms 42 arrest the parts to be welded in place. Since the protective chamber 3, as well as the fastening cassette 31, can be interchanged, their dimensions can be reduced to a minimum for the respective workpiece size, which reduces the protective gas consumption to a minimum. The drive mechanism 19 drives a driving wheel 15, which Can be arrested with the control spindles 14 and 17 in such a way that it selectively rotates either a driving wheel 13 acting on the hollow shaft 8, or a drive wheel 16 rotatably seated on the hollow shaft 8, which grips the electrode shaft 1 via an insulation material flange 19. If one of the driving wheels 13 and 16 is activated, the other remains unrotatably arrested on the frame 12' . In the illustrated case, the control spindle 14 switches the rotary drive to the hollow shaft 8 and arrests the - 7 - electrode shaft 1 so it cannot be rotated. In this case the connecting head 4 and the chamber 3 with the fastening cassette fastened on it rotate together with the pipe shaft 8. The parts A, B to be welded together rotate in respect to the welding electrode 2. Since the gas connections have been attached to the rotatable connecting head 4, they can be connected by means of hoses 53 to the chamber 3, as represented in Fig. 2. If a geometric shape formed by two cylinders is welded, the welding electrode 2 must follow the curved shape of the connecting, place. This is achieved by means of a threaded shaft 30, driven by a motor 29, which displaces a horizontal guide 28, which in turn displaces the aggregation constituted by a cylinder 25 and an arm 26. The arm 26 adheres to the electrode shaft 1, whose long rapid movement can be produced by means of the cylinder 25, which moves the arm 26 and a horizontal guide 27 in respect to the horizontal guide 28. The purpose of the rapid movement is to move the electrode 2 into the working position and away from it, while the precision movement of following the curved shape of the connecting place taking place during welding is produced by means of the motor 29. The precision displacement motor 29 is program controlled to perform its displacement movement as a function of the rotating movement of the pipe shaft 8. The welding current is brought to the welding spot from a current source 22, which is connected to a slide ring 21 fastened on the shaft 1 by means of an electric cable. The ground cable is connected to a slide ring 24, which is located on a flange 23. An electrical connection 49 exists from the - 8 - flange 23 to the protective chamber 3 and on to the fastening cassette 32 fastened therein. The insulating bearing sleeve 9 and the insulating flange 18 assure that the voltage applied to the shaft 1 is not transmitted to other parts of the device. The invention is not limited to the above examplary embodiment. In particular, the construction and shaping of the protective chamber 3 and of the positioning and fastening means inform of fastening cassette 31 connected therewith can vary in many ways. It is essential that both are fastened by means of. the same gripper elements 5 to the connecting head 4, wherein they are together interchangeable with such chambers and positioning and fastening means which are matched in shape and size to the respective pipe elements which are to be welded together. - 9 - We claim :- 1. A device for welding together cylindrical parts and rotary-elements, the device comprising : an electrode supporting shaft(1) which is a spindle that conducts the welding current to the welding electrode(2); a positioning and mounting device(31) for the parts to be welded(A,B); and a hollow shaft (8) enclosing the electrode supporting shaft (1), which is supported in bearings (10) and able to rotate with respect either to the supporting stage elements (11,12) or to the electrode supporting shaft (1), characterized in that attached to the hollow shaft (8), there is a connecting head(4) provided with fixing elements (5) for an interchangeable protective chamber(3), that the interchangeable means of positioning and fixing(31) together with the protective chamber (3) are so arranged that they are attached to the connecting head(4) with the same clamping elements(5) as those with which the protective chamber(3) is clamped, and that the device furthermore comprises : means(13,14,15,19) of rotating the hollow shaft(8) together with the connecting head(4) and the protective chamber(3) attached to it with the means of positioning and fixing(31); means(12',17,16,18) for locking the electrode supporting shaft (1) so that it cannot be rotated when the hollow shaft (8) rotates; and means(25,30) for moving the electrode supporting shaft(1) 10 axially with respect to the hollow shaft(8). 2.. The device as claimed in claim 1, wherein the above mentioned means for positioning and fixing(31) are located in the protective chamber(3). 3. The device as claimed in claim 2, wherein the means for positioning and fixing (31) are part of an interchangeable mounting cassette and that clamping and positioning elements(39,41,50) for the interchangeable mounting cassette(31) are provided in the protective chamber(3). 4. The device as claimed in claim 3, wherein clamping and positioning elements include guides(39) by means of which the mounting cassette(31) can be pushed in a direction along the axis of the electrode supporting shaft(1) into the intended position inside the protective chamber(3). 5. The device as claimed in claim 1, wherein the means (15,19) are part of the device and by which the electrode supporting shaft (l) can be rotated while other means(12',13,14) render the hollow shaft(8) unrotatable. 6. The device as claimed in claim 1, wherein on the connecting head(4), a thread insert(5) is provided, to which threaded sleeves(38,37) projecting from the protective chamber(3) can be fixed by threaded connections, and that the thread insert(5) is in one piece with a sleeve(6) enclosing the hollow shaft(8) and rotating as one with it, this sleeve(6) being 11 provided with protective gas ducts(7) which are connected to the protective chamber(3) by means of tubes (43) between the connecting head(4) and the protective chamber(3). 7. The device as claimed in claim 1, wherein the means(25-30) for imparting an axial movement to the electrode supporting shaft(1) include a motor(29) equipped with a threaded spindle(30). 8. The device as claimed in claim 1 or 7, wherein the axial movement imparted to the electrode supporting shaft(1) is controlled in such a way that it occurs simultaneously with the rotary movement of the electrode supporting shaft(1) and the hollow shaft(8) and as a function of this movement. 9. The device as claimed in claim l, wherein the electrode supporting shaft(1) in the hollow shaft(8) is supported in a bearing formed by a tube of insulating material(9). 12 A device for welding together cylindrical parts and rotary elements, wherein an axially displaceable electrode shaft(1) is provided in a rotatably seated pipe shaft(8) . The pipe shaft (8) can be rotated with respect to the electrode shaft(1) and a connecting head(4) is provided on one end of the pipe shaft(8), which is equipped with gripper elements(5) for an interchangeable protective chamber(3). Gripper and positioning elements for a fastening cassette(31) provided for the parts(A,B) to be welded together, which is also interchangeable, are arranged in the protective chamber(3). The electrode shaft(l) extends through the connecting head(4) into the protective chamber(3).

Full Text

The invention relates to a device for welding together cylindrical parts and rotary elements, comprising an electrode shaft, positioning and fastening means for the elements to be welded together and a hollow shaft surrounding the electrode shaft.
When cylindrical workpieces are welded, the contact surfaces generally have one of two types of shape. With cylindrical parts cut perpendicularly to the longitudinal axis, the ends meet and the abutting surface forms a circle. With this type of attachment by welding, a rotary friction welding process is involved, which is easily mechanized. When the cylinders meet at an angle, however, the abutting surface forms a geometrical shape which is dependent on the diameters of the cylinders and the angle at which the centrelines of the cylinders meet.
When there are several such cylinders branching off from a main cylinder, as in the case of pipe manifolds, and especially if they are close together, conventional welding from the outside becomes difficult. Such arrangements may be found, for example, in multiway valves, filter bodies, pipe junctions and similar components. When pipe junctions are welded, especially T-junctions, the limited height of the rabbet in the base cylinder and the size of conventional welding nozzles cause frequent problems.
The above mentioned problems can be eliminated by approaching the welding position from the inside of the junction cylinder. Then the limited height of the rabbet or a second junction in the
2

vicinity on the outside no longer constitute obstacles. The welding nozzle is at the height of the seam, while the workpiece (or the welding nozzle) turns around its own axis.
A second area of problems is constituted by long workpieces, whose rotation cannot be simply provided. A typical example of this is if distribution chambers are to be made from a pipe, wherein several pipe junctions are attached to a long pipe.
The coaxial alignment of the cylinders in respect to each other is of extreme importance. To assure the quality of the weld seam, it is necessary to protect the workpieces to be welded together from the oxygen in the air by enclosing the workpieces in a chamber filled with a protective gas. In order to minimize the amount of the protective gas and the fill time, the chamber must be as small as possible. However, the small size of the chamber in turn causes problems when inserting the workpiece in the holder located in the chamber. Because of the small size of the chamber it is not possible to simultaneously work with one' s hands in the chamber and to look into the chamber.
The object of the invention is based on providing a device by means of which the above described problems can be removed and the consumption of protective gas in particular can be reduced, even if the size of the workpieces to be welded together varies.
This object is attained by means of the characteristics
recited in the following eat claim 1. Advantageous embodiments
of the invention are recited in the dependent claims.
An exemplary embodiment of the invention will be explained

in greater detail in what follows, with reference to the accompanying
drawings.
- 3 -

Fig. 1 represents a device in accordance with the invention viewed from the side, wherein the portion above the centerline is shown in longitudinal section.
Fig. 2 shows in greater detail an example of the protective chamber as provided in a device in accordance with Fig. 1, and of the fastening cassette housed in the protective chamber and intended for the workpieces to be welded together, and
Fig.3 schematically represents a combination of the protective chamber and the fastening cassette corresponding to Fig. 2, viewed from the front, i.e. in the axial direction of the device.
Part of the device represented in Fig. 1 is a pipe shaft 8 which is seated rotatably in respect to the frame 12 in bearings 10. The support shaft 1 of the welding electrode 2 is a long shaft, which extends through the pipe shaft 8 concentrically in respect to the pipe shaft 8. An insulation material pipe 9, which is used as the bearing between these elements, is provided between the electrode shaft 1 and the pipe shaft 8. Thus, the electrode shaft 1 and the pipe shaft 8 are rotatable in respect to each other, and the electrode shaft 1 can moreover be moved in the axial direction.
The pipe shaft 8 is surrounded by a sleeve elements 6, which turns along with it, in which protective gas channels 7 are formed and which terminates at a widening forming a connecting head 4. The sleeve 6 extends over only a portion of the length of the pipe shaft 8. Next to the connecting head 4, the sleeve 6 is enclosed by a non rotatable frame sleeve 11 with the function of a structural housing which is fastened on the frame 12 to
- 4 -

prevent the rotation of the latter. This frame sleeve 11 with the function of a structural housing has the required connectors for the protective gas, the cooling gas and the compressed air required for the closing cylinder of the protective chamber 3. Rotatable connectors for providing the required gas connections to the channels 7 provided in the sleeve 6 and which end at the connecting head 4 are located between the sleeves 6 and 11. Only one channel 7 is represented in Pig. 1, but there are of course several of these, which are suitably distributed on the circumference of the sleeve 11 and of the connecting head 4.
A threaded bushing 5 with an interior thread is provided on the connecting head 4, to which the protective chamber 3 can be connected by means of a threaded connector. The positioning and fastening means inform of fastening cassette 31 for the parts A, B to be welded together are fastened on the threaded bushing 5 of the connecting head 4. This is only schematically indicated in Fig.l. An exemplary embodiment is shown more detailed in Fig. 2, wherein the bottom section 32 of the protective chamber 3 is provided with a projecting neck 38, which is surrounded by a threaded sleeve 37, by means of which the chamber 3 can be fastened on the threaded bushing 5. The upper section 33 of the chamber 3 can be closed by means of the rod 35 of the piston of a cylinder 34. The upper section 33 is guided on vertical guides 48, whose upper ends are fastened on the cylinder 34. By means of seals 36 it is assured that the closed chamber 3 is tight.
- 5 -

The fastening
cassette 31 intended for the workpieces to be welded together is pushed into the chamber 3, guided by guides 39 located on the bottom of the chamber. The guides 39 extend parallel with the axial direction of the electrode shaft 1, wherein the cassette slides in the axial direction of the electrode shaft into its intended position. Grooves 40 for the guides 39 are formed at the edges of the bottom of the positioning and fastening means inform of fastening cassette 31. The workpieces to be welded together are correctly positioned in respect to the welding electrode 2. A stop 41, which can be fixed in place or axially adjustable, is provided at the end of the guides 39 for the axial positioning taking place in the axial direction. A spring loaded pressure element 50 is arranged on the ceilling of the chamber which, when the upper section of the chamber has been lowered, meets the rear edge of the positioning and fastening means inform of fastening cassette 31, its upper and rear side, keeping the positioning and fastening means inform of fastening cassette 31 fixed in its place.
In the case represented, arms 42, which can be pivoted around a hinge shaft with an axle 43, are a part of the positioning and fastening means inform of fastening cassette 31, which arms have a spring loaded arresting element 45 at their ends, which grasps the cassette behind the upper edge of its front 46. Sleeves 44 project from the arresting element 45, which sleeves contain springs which have been pressed between the bottom of the sleeve 44 and the ends of the arms 42. If the arresting element 45 in
- 6 -

Fig.2 is pulled to the right against the force of the springs, the arms 42 can be pivoted upward around the hinge shaft with an axle 43.
The workpieces to be welded are placed into the cassette 31 while it is outside of the chamber 3. There are typically two cassettes 31 per chamber 3 so that, while a first cassette 31 is in the chamber 3, the other cassette 31 can be filled with parts to be welded. A regulating screw 47 determines the position of the parts, and the downward pivoted arms 42 arrest the parts to be welded in place. Since the protective chamber 3, as well as the fastening cassette 31, can be interchanged, their dimensions can be reduced to a minimum for the respective workpiece size, which reduces the protective gas consumption to a minimum.
The drive mechanism 19 drives a driving wheel 15, which Can be arrested with the control spindles 14 and 17 in such a way that it selectively rotates either a driving wheel 13 acting on the hollow shaft 8, or a drive wheel 16 rotatably seated on the hollow shaft 8, which grips the electrode shaft 1 via an insulation material flange 19. If one of the driving wheels 13 and 16 is activated, the other remains unrotatably arrested on the frame 12' . In the illustrated case, the control spindle 14 switches the rotary drive to the hollow shaft 8 and arrests the
- 7 -

electrode shaft 1 so it cannot be rotated. In this case the connecting head 4 and the chamber 3 with the fastening cassette fastened on it rotate together with the pipe shaft 8. The parts A, B to be welded together rotate in respect to the welding electrode 2. Since the gas connections have been attached to the rotatable connecting head 4, they can be connected by means of hoses 53 to the chamber 3, as represented in Fig. 2.
If a geometric shape formed by two cylinders is welded, the welding electrode 2 must follow the curved shape of the connecting, place. This is achieved by means of a threaded shaft 30, driven by a motor 29, which displaces a horizontal guide 28, which in turn displaces the aggregation constituted by a cylinder
25 and an arm 26. The arm 26 adheres to the electrode shaft 1,
whose long rapid movement can be produced by means of the
cylinder 25, which moves the arm 26 and a horizontal guide 27
in respect to the horizontal guide 28. The purpose of the rapid
movement is to move the electrode 2 into the working position
and away from it, while the precision movement of following the
curved shape of the connecting place taking place during welding
is produced by means of the motor 29. The precision displacement
motor 29 is program controlled to perform its displacement movement
as a function of the rotating movement of the pipe shaft 8.
The welding current is brought to the welding spot from
a current source 22, which is connected to a slide ring 21
fastened on the shaft 1 by means of an electric cable. The
ground cable is connected to a slide ring 24, which is located
on a flange 23. An electrical connection 49 exists from the
- 8 -

flange 23 to the protective chamber 3 and on to the fastening cassette 32 fastened therein. The insulating bearing sleeve 9 and the insulating flange 18 assure that the voltage applied to the shaft 1 is not transmitted to other parts of the device. The invention is not limited to the above examplary embodiment. In particular, the construction and shaping of the protective chamber 3 and of the positioning and fastening means inform of fastening cassette 31 connected therewith can vary in many ways. It is essential that both are fastened by means of. the same gripper elements 5 to the connecting head 4, wherein they are together interchangeable with such chambers and positioning and fastening means which are matched in shape and size to the respective pipe elements which are to be welded together.
- 9 -

We claim :-
1. A device for welding together cylindrical parts and rotary-elements, the device comprising :
an electrode supporting shaft(1) which is a spindle that conducts the welding current to the welding electrode(2);
a positioning and mounting device(31) for the parts to be welded(A,B); and
a hollow shaft (8) enclosing the electrode supporting shaft (1), which is supported in bearings (10) and able to rotate with respect either to the supporting stage elements (11,12) or to the electrode supporting shaft (1), characterized in that
attached to the hollow shaft (8), there is a connecting head(4) provided with fixing elements (5) for an interchangeable protective chamber(3), that the interchangeable means of positioning and fixing(31) together with the protective chamber (3) are so arranged that they are attached to the connecting head(4) with the same clamping elements(5) as those with which the protective chamber(3) is clamped, and that the device furthermore comprises :
means(13,14,15,19) of rotating the hollow shaft(8) together with the connecting head(4) and the protective chamber(3) attached to it with the means of positioning and fixing(31);
means(12',17,16,18) for locking the electrode supporting shaft (1) so that it cannot be rotated when the hollow shaft (8) rotates; and
means(25,30) for moving the electrode supporting shaft(1)
10

axially with respect to the hollow shaft(8).
2.. The device as claimed in claim 1, wherein
the above mentioned means for positioning and fixing(31) are located in the protective chamber(3).
3. The device as claimed in claim 2, wherein
the means for positioning and fixing (31) are part of an interchangeable mounting cassette and that clamping and positioning elements(39,41,50) for the interchangeable mounting cassette(31) are provided in the protective chamber(3).
4. The device as claimed in claim 3, wherein
clamping and positioning elements include guides(39) by means of which the mounting cassette(31) can be pushed in a direction along the axis of the electrode supporting shaft(1) into the intended position inside the protective chamber(3).
5. The device as claimed in claim 1, wherein
the means (15,19) are part of the device and by which the electrode supporting shaft (l) can be rotated while other means(12',13,14) render the hollow shaft(8) unrotatable.
6. The device as claimed in claim 1, wherein
on the connecting head(4), a thread insert(5) is provided, to which threaded sleeves(38,37) projecting from the protective chamber(3) can be fixed by threaded connections, and that the thread insert(5) is in one piece with a sleeve(6) enclosing the hollow shaft(8) and rotating as one with it, this sleeve(6) being
11

provided with protective gas ducts(7) which are connected to the protective chamber(3) by means of tubes (43) between the connecting head(4) and the protective chamber(3).
7. The device as claimed in claim 1, wherein
the means(25-30) for imparting an axial movement to the electrode supporting shaft(1) include a motor(29) equipped with a threaded spindle(30).
8. The device as claimed in claim 1 or 7, wherein
the axial movement imparted to the electrode supporting shaft(1) is controlled in such a way that it occurs simultaneously with the rotary movement of the electrode supporting shaft(1) and the hollow shaft(8) and as a function of this movement.
9. The device as claimed in claim l, wherein
the electrode supporting shaft(1) in the hollow shaft(8) is supported in a bearing formed by a tube of insulating material(9).

12
A device for welding together cylindrical parts and rotary elements, wherein an axially displaceable electrode shaft(1) is provided in a rotatably seated pipe shaft(8) . The pipe shaft (8) can be rotated with respect to the electrode shaft(1) and a connecting head(4) is provided on one end of the pipe shaft(8), which is equipped with gripper elements(5) for an interchangeable protective chamber(3). Gripper and positioning elements for a fastening cassette(31) provided for the parts(A,B) to be welded together, which is also interchangeable, are arranged in the protective chamber(3). The electrode shaft(l) extends through the connecting head(4) into the protective chamber(3).

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Patent Number

201687

Indian Patent Application Number

IN/PCT/2000/00421/KOL

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

23-Feb-2007

Date of Filing

19-Oct-2000

Name of Patentee

EFES TEX AG

Applicant Address

VIA DUFOUR 2 CH-6901 LUGANO

Inventors:

#	Inventor's Name	Inventor's Address
1	LEO LARIKKA	VAAHTORINNE 3B 22, FIN-01600,VANTA

PCT International Classification Number

B23K 9/028

PCT International Application Number

PCT/IB99/00717

PCT International Filing date

1999-04-22

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	0954/98	1998-04-28	Switzerland