Patent ID: 8506282
Filing Date: 2013-08-13
Classification: B21D,B26D,B26F,Y10T

Abstract:
1. A die comprising: a die body having an outermost side portion and provided at its upper portion with a die hole; a discharge hole formed in the die body and having a diameter larger than that of the die hole; a peripheral groove formed at an outer peripheral surface of the die body and at the middle height portion of the die body, so that an inclined surface is formed at the peripheral groove; and an inclined air injection hole having a generally uniform diameter and having an upper end and a lower end, the upper end being opened into the inclined surface so as to break through the inclined surface, the lower end being opened into a lower portion of the discharge hole, such that the air injection hole is configured to inject air from the upper end into the discharge hole downwardly, wherein a longitudinal axis of the inclined air injection hole intersects at a right angle with the inclined surface such that the inclined surface is free from slippage surfaces upon which a tip end of a hole-forming tool would otherwise slip on when the hole-forming tool forms the inclined air injection hole, and wherein an edge of the upper end of the inclined air injection hole intersects with the outermost side portion of the die body, wherein the inclined surface has an arcuate cross-sectional shape and a curved surface, and wherein the longitudinal axis of the air injection hole intersects, at a right angle, with a tangent at an intersection point between the longitudinal axis of the air injection hole and the curved surface of the inclined surface.