Paperboard slitting apparatus

Claim 1

Rotary slitting apparatus for slitting paperboard material comprising in combination: an annular head member including a reduced diameter shoulder portion adjacent one side face thereof forming a first annular side face extending at a small angle of from between 3 degrees and 7 degrees from a line extending radially perpendicular from a central axis of said head member towards a larger diameter surface thereon; a thin annular slitting blade member adjacent said first annular side face and including an inner annular surface surrounding said reduced diameter shoulder portion and having a plurality of circumferentially spaced notches extending radially part way from said inner annular surface toward an outer annular surface, said outer annular surface extending at an angle of from between 5 degrees and 40 degrees from a plane perpendicular to side faces thereof forming an acute angle cutting edge with one of said side faces; and an annular clamp member including an inner annular surface surrounding said reduced diameter shoulder portion and having a second annular side face, adjacent said blade member, extending radially at an angle from a central axis of said head member so as to correspond to said small angle of said first annular side face for clamping said blade member at an angle against said first annular side face on said head member, said head member further including an annular relief formed in said first annular side face opposite to the termination of said notches in said slitting blade member, and said clamp member further including an annular relief formed in said second annular side face opposite to the termination of said notches in said slitting blade member.