VORRICHTUNG UND VERFAHREN ZUM SCHNEIDEN BLATTFOERMIGEN MATERIALS

摘要

In a reciprocating blade for cutting sheet material, a lower cutting part includes a forward cutting edge defining portion and a rear body portion. The body portion has two parallel side faces. The cutting portion has first, second, third and fourth side surfaces. The first side surface is located in a reference plane parallel to and mid-way between the side faces of the body portion. The fourth side surface is in the same plane as one of the side faces of the body portion. The second side surface is inclined to the reference plane, extends between one side face of the body portion and the first side surface, and intersects the first side surface to define the cutting edge. The third side surface is inclined to the reference plane and extends from the rear of the first side surface to the other side face of the body portion. At least the first side surface is covered with a layer of hard material. During use of the blade the second side surface is periodically sharpened. As a result of this construction and method of use the cutting edge is provided by the hard material, the cutting edge remains on the middle reference plane throughout the service life of the blade, and the lateral forces imposed on the blade by the cut material are substantially balanced throughout the service life of the blade.