CUT OFF BLADE FOR SEVERING MULTIPLE LAYERS OF THIN POLYMERIC SHEET MATERIAL

摘要

A cut off blade adapted for severing plastic film material folded in layers. The blade is a thin metal sheet including an attachment portion and a plurality of similarly shaped teeth defining a cutting edge portion of the blade. Each of the teeth defines parts of the first and second major surfaces in the shapes of isosceles triangles with two equal length sides terminating in points and having bases adjacent the attachment portion and aligned in a first direction along the blade so that the points project at right angles to the first direction. The angle between any portion of an edge surface of the blade along the cutting edge portion and the second surface when measured in a plane normal to the first direction is the same acute angle, and the metal of the sheet defining the edge surface along the cutting edge has been cold flowed toward the intersection thereof with the second major surface by a punch and die forming method to define a sharp edge at that intersection.