1,044,435. Cutting several windows in envelope blanks. R. WINKLER, and K. DUNNEBIER. Jan. 22, 1965 [Jan. 24, 1964], No. 2843/65. Heading B5D. Envelope or bag blanks are first held on a cutter roller 9 (Fig. 1), by suction applied to ports 101, 11<SP>1</SP>, 12<SP>1</SP> within several closed window cutting knives 10, 11, 12, and the portions cut away (by co-operation of a counter roller) are subsequently ejected by air blown from the ports. The timing of the supply of suction and pressure can be varied for each knife independently, e.g. by rotary valves 30<SP>1</SP>, 31<SP>1</SP>, 32<SP>1</SP> leading to the supply of suction and pressure. The position of a guide on the cutting roller for the leading edges of the blanks can be varied. The guide may comprise a blade 49 (Fig. 6, not shown), or a row of ports 38 (Fig. 1), alternately fed with suction and with pressure and carried by a sleeve 18 which can be adjusted about the circumference of the roller 9. The positions of the knives on the roller 9 are adjustable.