VERFAHREN UND VORRICHTUNG ZUR AUTOMATISCHEN BESTIMMUNG DES BEGINNS EINES SCHWEISSPROZESSES ZUR HERSTELLUNG VON RÖHRENFÖRMIGEN ETIKETTEN

摘要

The invention pertains to the field of apparatuses for automatically determining the beginning of a welding process which makes tubular labels of plastic film. The device comprises a welding element, such as a sonotrode (2) for performing an ultrasonic welding, which is mounted to turrets of a labelling machine. The device is formed of two parts, one movable and one stationary fixed to the turret and comprises sliding elements engaged in a respective guide (4) which allow the sonotrode (2) to slide when it is stopped by the opposite resistance of the object to be welded. Meanwhile, since the distance between said stationary and movable elements diminishes, a spring (11) is compressed and a sensor (8) triggers the translation and welding step. The spring (11) move the sonotrode (2) back to the initial position when the device (1) is moved away from the welded label. The process provides that the welding vertical translating step starts when the sonotrode contacts the labels to be welded.