(57) A fast-cutting device in a machine for packaging in a film of plastic material, in
said machine there being provided at least two pairs of rollers (12, 13) for feeding
a film (11) towards a packaging area, between the two pairs of rollers (12, 13) there
being provided a cutting assembly (14, 15, 16) which acts crosswise on the film (11),
in said device the cutting assembly (14) comprising at least one blade (15) rotating
in the operating phase around a shaft (25) caused to rotate by a gearing system designed
to convert a uniform rotation at input into a variable rotation at output (27, 28),
being selectively driven by a motor (18) for unrolling the film with interposition
of a brake-clutch assembly (22). The said gearing system may be a transmission with
elliptical gears (27, 28). In addition, a counterblade (16) may be provided that rotates
in the operating phase together with the blade (15) around a shaft (26).
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