Patent ID: 6951313

Claim:
A knife for use with a rotary cutter disk having first and second surfaces with at least one opening therethrough which defines a passageway through the disk from said first to said second surfaces for cut chips to pass therethrough and a knife holder mounted adjacent to said opening, said knife comprising, a knife body having a first knife edge forming surface and a chip breaking surface associated with the first knife edge forming surface and extending at an angle thereto, said first knife edge forming surface and said chip breaking surface intersecting to define a cutting edge, and a rib projecting from said body parallel to and spaced from said cutting edge below said knife edge forming surface, said chip breaking surface including a planar portion that, at approximately a central portion of said chip breaking surface, transitions to a continuously smoothly curved generally concave chip directing portion, said planar portion extending from said cutting edge at an acute angle with respect to said knife edge forming surface and extending to said concave chip directing portion, said rib having (i) a first, chip directing portion which defines said chip directing portion of the knife extending outwardly from said planar portion of said chip breaking surface generally along a first plane which is transverse to a second plane defined by said first knife edge forming surface and (ii) a first knife support surface oriented along a third plane which diverges outwardly from the knife body, behind said chip deflecting surface and at an acute angle to said chip deflecting surface, said acute angle being defined substantially within the rib between said first and third planes, said first knife support surface and said chip deflecting surface converging to form a tip portion of said rib, said first and third planes intersecting substantially at said tip portion, and said second and third planes intersecting at a point located within the area of a projection of the knife onto said second plane and outside the area occupied by the knife.