Abstract: The invention relates to an ultrasonic welding device comprising a sonotrode (1) secured to an amplifier (12), and this in turn being secured to a converter (13), on which the head (2) is secured, characterised by comprising an external casing (3) disposed around the sonotrode (1), together delimiting an annular chamber (4) for the circulation of pressurised air having a crenellated opening in the front end (31) thereof for the output of pressurised air and the cooling of the sonotrode (1), wherein said external casing (3) has a rear portion (32) on the head (2) that can move axially, forming a presser plate which exerts a pressure—owing to the action of compressible means (51)—against the parts (P1, P2) to be welded, in a peripheral zone next to the welding zone, before the tip (11) of the sonotrode (1) comes into contact with said parts to be welded.

Abstract: The invention relates to an ultrasonic welding device comprising a sonotrode (1) secured to an amplifier (12), and this in turn being secured to a converter (13), on which the head (2) is secured, characterised by comprising an external casing (3) disposed around the sonotrode (1), together delimiting an annular chamber (4) for the circulation of pressurised air having a crenellated opening in the front end (31) thereof for the output of pressurised air and the cooling of the sonotrode (1), wherein said external casing (3) has a rear portion (32) on the head (2) that can move axially, forming a presser plate which exerts a pressure—owing to the action of compressible means (51)—against the parts (P1, P2) to be welded, in a peripheral zone next to the welding zone, before the tip (11) of the sonotrode (1) comes into contact with said parts to be welded.