This invention relates to an apparatus for producing packaging blanks by severing a continuous sheet, in which apparatus the sheet and the blank are transported and guided by revolving conveyor bands to which suction is applied in at least some regions.
The processing of delicate packaging material presents problems in the packaging industry. Thin-walled plastic foils require special measures regarding the transport and fixing of the packaging material until it is wrapped round the article to be enveloped. This is particularly true when such packaging materials are processed in high-performance packaging machines, for example, when cigarette packs are enveloped in an outer wrapper.
In a known apparatus of this type (U.S. Pat. No. 4,151,699), a necessary severing cut is made transversely to the sheet of packaging material to sever the individual blanks in successive part cuts. Preparatory cuts are made in the lateral region of the sheet, in the region of a first severing device, but these do not break the connection between the blank marked in this way and the sheet. A main cut is then made in the region of a second severing device, and this cut follows the preparatory cuts and severs the blank completely from the sheet. At the same time, the sheet and blank are transported over a part distance by conveyor bands to which suction is applied via suction holes and which fix the sheet and blank respectively by means of suction during transport. The main cut is made in the region of these conveyor bands and between them. As a result, an uninterrupted positive guidance of the sheet and the severed blanks is ensured until they are received by a cigarette pack.