Device for punching out a joint part and for welding the latter to a workpiece, and ultrasonic horn for use in such a device

The invention relates to a device with which, in a single operation, joint parts to be welded are punched out of thin strip material and are reliably conveyed and welded to corresponding workpieces, the entire operation being monitored automatically. The welding die (23) of a welding tool (4) of the device is designed as a punching die, the welding tool (4) has holding means and a punching tool (9) of the device has a guide bush (10) and a punching tool (9) of the device has a guide bush (10) and a punching bush (11) through which the welding die (23) is guided as far as the workpiece (15) to be welded. A subatmospheric pressure line is provided in the welding tool (4) as holding means. Theconnection of a subatmospheric pressure monitor (24) into thesubatmospheric pressure line enables not only the monitoring ofthe presence of the punched-out joint part until directly beforewelding, but also the testing of the success of the welding operation.