Abstract: The invention relates to a method for positioning a welding bolt (15), held in a bolt welding head (3), whereby the robot (5), to which the bolt welding head (3) is fixed, moves the bolt welding head sideways until a touch sensor (21) contacts a side wall (25) of a workpiece. The position of the side wall (25) is thus detected and the bolt welding head (3) can be moved through a set amount (Y) into a welding start position, from whence the welding bolt (15) can be welded to the workpiece (9) by the displacement in the direction of travel (V). The welding bolt (15), thus, always has the required separation (Z) from the side wall (25), independent of tolerances in the workpiece.

Abstract: The invention relates to a method for welding a bolt (19) onto a workpiece, using a bolt-welding device and to a bolt-welding device. A force is applied to the drive shaft (11) using a switchable unit (29), said force exerting a resistance against a displacement of the drive shaft (11). The drive shaft (11) is moved by an electromagnetic linear drive (5) acting in an axial direction. The unit (29) can prevent the movement of the drive shaft (11) and can fix the latter in position, in such a way that the linear drive (5) can be switched to a currentless state. In addition, the unit can dampen the movement of the drive shaft (11).

Abstract: The invention relates to a stud welding head with a linear drive (5), a welding pin (11) coupled with said linear drive (5), and a length metering system (7) that determines the position of the welding pin (11) in the stud welding head, said length metering system (7) being an electromagnetic length metering system.

Abstract: A stud welding machine features several welding outputs for welding tools with different polarity for various welding operations. The polarity of at least one welding output is reversible.

Abstract: This electric stud-welding device includes a welding gun for a stud or bolt to be welding to a workpiece, and a control device. The latter consists of a welding current source and a setting device for welding time and welding current. The welding gun and the control device are connected through two welding current lines. A pilot current circuit is present, using only the two welding current lines (5, 6). Also present is a setting device (10), coordinated with the welding gun (3), which is switched into the pilot current circuit. In the control device (2), there is a sensor (9) which, dependent on the control signals produced by the setting device (10) each time, after the actuation of the selective switches or setters (13, 14) arranged thereon, controls the control device (8), present in the control instrument, for the welding time and the welding current.