Apparatus for perforating running webs of wrapping material and cleaning devices therefor

摘要

Apparatus for perforating a running web of wrapping material, such as a web of tipping paper in a filter tipping machine for the making of filter cigarettes, is advanced through two successive electric perforating units one of which is active while the other is idle, and vice versa. This renders it possible to clean the perforating electrodes of the idle unit while the electrodes of the active unit produce sparks which remove fragments of material from the web to form one or more rows of perforations and to thus influence the permeability of the web. The apparatus can be installed in a filter tipping machine between a reel for a supply of convoluted web of tipping paper and a severing device which subdivides the leader of the perforated web into uniting bands serving to connect pairs of plain cigarettes with filter mouthpieces of double unit length.