| 摘要 |
To weld together thermoplastic foils to form folders or binder jackets (1), in which the thermoplastic material is difficult to weld by externally supplied heat, an ultrasonic generator is coupled to a plurality of sonotrodes (41), assembled in a sonotrode system (17), against which a welding head (16) is reciprocated, with the foils (24) between the welding head and the sonotrode system (17). The sonotrodes are excited by ultrasonic energy, and secured to a machine frame (14) by attachment posts (45, 45') which are coupled to the sonotrodes (41) or the machine frame (14), respectively, at locations where the sonotrodes or the posts, respectively, have wave nodes when excited to ultrasonic oscillations, so that, effectively, no ultrasonic energy is coupled to the machine frame. The ultrasonic energy is supplied to the sonotrodes by an ultrasonic generating system (52, 53) coupled to one surface (51) of a beam or rail-like sonotrode (41), the opposite surface (42) of which forms an engagement surface for the plastic foils (24), pressed thereagainst by welding edges (68), and optionally having cutters (67, 68) thereon to sever welded foils or jackets (1) adjacent the location where respective weld seams (8, 9, 11) have been made. |
