Welding torch with a fixing element for the gas nozzle, said element being capable of extension; process control method for a welding system equipped with said welding torch; gas nozzle for said welding torch; and contact tube for said welding torch

1. A single or multi-wire welding torch which can be connected to a welding device via a hose pack, the single or multi-wire welding torch comprising a torch handle, a tubular welding torch housing, at least one contact tube for welding wire, and a gas nozzle,

wherein an internal insert for receiving said at least one contact tube and said gas nozzle is mounted in an end area of said tubular welding torch housing,

wherein a fixing element is placed on said internal insert for producing a gas-tight connection between said internal insert and said gas nozzle pushed thereon,

wherein said fixing element is made at least partially of a flexible material, with said gas-tight connection being establishable by spatial expansion of said fixing element,

wherein a circumferential recess is provided on said internal insert, said circumferential recess having an opening connected with a supply device,

wherein said fixing element is provided in said circumferential recess,

wherein said internal insert has a body of insulating material,

wherein at least one contact socket for electric energy transmission is provided in said body for receiving said at least one contact tube, and

wherein said circumferential recess is located on an outside of the internal insert.

2. A laser-hybrid single or multi-wire welding head comprising:

at least one mounting element, and

a first group of components on the at least one mounting element, the first group of components comprising a laser or a laser lens system, a crossjet and welding torch components for arc welding, said first group of components being connectable to a laser beam source and a welding device for melting wire welding processes via lines,

wherein said welding torch components have an internal insert for receiving at least one contact tube and a gas nozzle,

wherein a fixing element is provided on said internal insert for producing a gas-tight connection between said internal insert and said gas nozzle pushed thereon, and

wherein said fixing element is made at least partially of a flexible material, with said connection being establishable by spatial expansion of said fixing element,

wherein a circumferential recess is provided on said internal insert, said circumferential recess having an opening connected with a supply device,

wherein said fixing element is provided in said circumferential recess,

wherein said internal insert has a body of insulating material,

wherein at least one contact socket for electric energy transmission is provided in said body for receiving said at least one contact tube, and

wherein said circumferential recess is located on an outside of the internal insert.

3. The single or multi-wire welding torch according to claim 1 , wherein said fixing element is formed by a deformable elastic hose or a sealing element.

4. The single or multi-wire welding torch according to claim 3 , wherein said deformable elastic hose or said sealing element is made of ethylene propylene diene monomer or silicone.

5. The single or multi-wire welding torch according to claim 1 , wherein said fixing element is formed by a membrane.

6. The single or multi-wire welding torch according to claim 1 , wherein said fixing element is coupled with said supply device via said opening in said recess such that a deformable or yielding area of said fixing element is subjected to a pressure.

7. The single or multi-wire welding torch according to claim 6 , wherein said supply device has a hydraulic or pneumatic pressure producing device.

8. The single or multi-wire welding torch according to claim 6 , wherein said supply device is a hydraulic or pneumatic supply device, and

wherein said fixing element is connected via said opening in said recess to a duct for a fluid, which duct is connected to said hydraulic or pneumatic supply device via a feed line.

9. The single or multi-wire welding torch according to claim 6 , wherein said supply device is formed by an inert gas supply device of said welding device or is formed by a separate compressed air device.

10. The single or multi-wire welding torch according to claim 6 , wherein said supply device is formed by a separate compressed air device, and

wherein said separate compressed air device is provided to supply said fixing element and simultaneously to form a crossjet in a laser welding process.

11. The single or multi-wire welding torch according to claim 1 , wherein the gas-tight connection is between a cylindrical interior surface of said gas nozzle and said internal insert and is frictional.

12. The single or multi-wire welding torch according to claim 1 , wherein one section and/or contact surface of at least one of said fixing element and an internal surface of said gas nozzle is structured.

13. The single or multi-wire welding torch according to claim 1 , wherein said at least one contact tube is pluggable.

14. The single or multi-wire welding torch according to claim 1 , further comprising a sensor to monitor said gas nozzle.

15. The single or multi-wire welding torch according to claim 1 , wherein said internal insert is made of two semi-spheres or a number of individual parts.

16. The single or multi-wire welding torch according to claim 1 , wherein said tubular welding torch housing has an exit opening for a welding wire and, opposite, a receiving area for mounting on said internal insert, and

wherein inside said tubular welding torch housing a receiving element is provided for said at least one contact tube, with said receiving element electrically insulating said at least one contact tube against said tubular welding torch housing.