Abstract: 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.

Abstract: To apply a reinforcing element (9) only at the position of an index tab (7) on stock material, in which the position of the index tab, for example alphabetically, shifts from stock material to stock material, the stock material (2) is passed through a groove (27, 27a . . . 27f) extending axially along a cylinder or drum (22), the reinforcements being derived upon cutting a ribbon (15) which is folded longitudinally, and inserted into a groove (27e) of the cylinder while the reinforcement at the opposite side of the cylinder is being applied on the stock material, slid into the groove by a transport system. For application, heated tines press, from the top and bottom, against the reinforcement, by passing through circumferential grooves (69) of the drum or cylinder (22). A movable stop system (17) longitudinally positions the stock material (2) for staggered application of the reinforcements.