Method for cutting a moving web of material

A method for cutting a running web, comprising the steps:

• guiding the web over a circumferential surface of an abutment drum;
• rotating a blade, that extends in the axial direction of the abutment drum, about an axis of rotation parallel to the axis of the abutment drum;
• holding the blade in a retracted position in which a cutting edge of the blade is spaced apart from the web on the abutment drum;
• impacting the blade against the web and the surface of the abutment drum at a time when the blade passes through a plane that contains the axis of the abutment drum and said axis of rotation;
• supporting a knife shaft carrying the blade in a crank-rocker which in turn is mounted on a rotary eccentric;
• and
• controlling the impact movement of the blade by controlling a drive of the eccentric such that the eccentric moves with an angular acceleration and the angular velocity of the eccentric is at a maximum when the blade passes through said plane.