Patent ID: 8011280

Claim:
A rotary cutter for trimming printed products, conveyed in an overlapping flow, the rotary cutter comprising: a first knife that rotates; a second knife that rotates counter to the first knife, wherein the second knife is arranged to operate jointly with the first knife and planes of faces of the first and second knives are arranged substantially perpendicular to the conveying direction; wherein at least one of the first knife or the second knife includes a plurality of blades distributed over a circumference of at least one of the first knife or the second knife; a conveying device to convey the overlapping flow between the first knife and the second knife; a thickness measuring device arranged to detect a thickness of the overlapping flow; a speed measuring device arranged to detect a speed of the overlapping flow; and a control unit coupled to receive outputs of the thickness measuring device and speed measuring device to automatically control and adjust a rotational speed of at least one of the first knife and the second knife based on the speed of the overlapping flow and the thickness of the overlapping flow.