Abstract: An apparatus for applying transverse welds on a plastic foil web in dependence on the print register is provided with a conveyor which is advanced by means of a control unit intermittently and synchronously with respect to a welding unit. The control unit includes a drive disk whose eccentric pin is adjustable and guided by an eccentric block. Via a coupling rod, the drive disk is connected to a rocker which is accommodated in a gear segment and whose oscillation is adjustable by a spindle. The gear segment cooperates with the conveyor via a clutch-brake unit which provides the intermittent advance of the conveyor by uncoupling from or connecting the latter with the gear segment and is controlled by a plurality of contactless switch elements. For precise adjustment of the advance of the conveyor, the spindle cooperates with a motor which operates in dependence on the print register as monitored by a photocell.