Being the down cutting type crop shear where decisive manner of edge form of the down cutting type crop shear and the upper blade material and the upper blade material and

摘要

PROBLEM TO BE SOLVED: To provide a down-cut type crop shear for suitably cutting a thick steel plate, and also to provide an upper blade material.;SOLUTION: The down-cut type crop shear comprises an upper blade holder on which the upper blade material having an upper blade is mounted, and a lower blade holder on which a lower blade material having a lower blade is mounted, wherein the upper blade holder is moved down in the vertical direction and the lower blade holder is fixed when shearing a thick steel plate. The upper blade material has upper blades on two ridges not neighboring each other in a blade cross direction, or on two ridges point-symmetrical with a straight line passing through a center in the blade cross direction and perpendicular to a cutting plane, as an axis. When it is mounted on the upper blade holder, the rake angle on the blade root side in use for shearing are greater than the rake angle on the blade tip side. The upper blade material is bolted to the upper blade holder so that the blades provided on the two ridges of the upper blade material are used in sequence. It has the blades shaped into a plurality of straight blades continuing across an inflection point in the blade cross direction. When the upper blade material is mounted on the upper blade holder, the straight blades have rake angles becoming gradually smaller from the blade root side toward the blade tip side.;COPYRIGHT: (C)2009,JPO&INPIT