Packaging machine

A packaging machine comprising a cutting assembly configured to longitudinally cut a film during a displacement of the film in a forward direction, the cutting assembly comprising:

• a rotary shaft with a longitudinal axis transverse to the forward direction;
• a cutting disc that is coupled to and rotates with the rotary shaft, the cutting disc being axially displaceable with respect to the rotary shaft between an inactive position and an active position;
• an auxiliary member configured to cooperate with the cutting disc to cut the film when the cutting disc is in the active position;
• and
• a positioning mechanism configured to cause axial displacement of the cutting disc with respect to the rotary shaft at least to position the cutting disc in the active position, the positioning mechanism comprising:
• a first positioning member coupled to the cutting disc such that the first positioning member and the cutting disc are together axially displaceable with respect to the rotary shaft;
• a second positioning member coupled to the rotary shaft without the possibility of relative displacement with respect to the rotary shaft;
• a chamber confined between the first positioning member and the second positioning member, the positioning mechanism being configured such that when a pressure inside the chamber is modified the first positioning member is axially displaced with respect to the rotary shaft so that the cutting disc at least passes from the inactive position to the active position.