Non-contacting slitter

Claim 1

In a slitter for slitting springy compressible paper web having a K 2 factor under 100, and having a pair of cooperating circular rotary members: said members having cooperating peripheral web severing continuously circular edges having severance points at their closest approach to one another is spaced non-contacting radial opposition for engaging therebetween a running paper web to be slit; peripheral surfaces on said members sloping on respective shallow angles away from said edges and said edges overlapping not in excess of 0.010 inch; and means mounting said members for maintaining a spacing between said severance points no greater than 30% of the thickness of the running paper web and so related to the plane and the physical properties of said web as to cause radial thrusting compression pinching of the web to as nearly as practicable equal extent indentation from each face of the web by and between said severance points, so that fiber failure by separation fracture is caused, starting substantially at the center of the thickness of the web in substantially radial alignment with said severance points, due to the intense internal stresses imposed on the web by the severance points progressively along a predetermined severance line in the continuous severance of said running web.