Apparatus for the transversal welding and severing of superposed webs

Abstract

An apparatus for the periodic transverse welding and severing of longitudinally advanced superposed wrapper sheets has two oppositely rotating, cooperating welding shoes, at least one of which is provided with a heater and at least one of which is displaced towards its rotary axis by virtue of the engagement between the welding shoes during each revolution thereof. One welding shoe has a tapered terminal head which includes leading and trailing flanks as well as a cutting edge. The other welding shoe has a counterface cooperating with the cutting edge and two elastic, rod-like members arranged adjacent and parallel to the counterface. As the welding shoes simultaneously engage the superposed wrapper sheets from opposite sides, the leading flank of the tapered head, cooperating with one of the elastic rod-like members pinches the wrapper sheets and provides a first transverse weld seam. Thereafter, the cutting knife, cooperating with the counterface, severs the sheets adjacent and parallel to the first weld seam. Subsequently, the trailing flank of the tapered head, cooperating with the other elastic rod-like member, pinches the wrapper sheets and provides a second transverse weld seam adjacent and parallel to the transverse cut.