HOLE CUTTING AND PUNCHING DIE (VERSIONS) Russian patent published in 2010 - IPC B21D28/14 B26F1/14 

FIELD: metallurgy.

SUBSTANCE: die includes puncheons with shoulders, punch holder, lower plate and puncheon-matrix. In accordance with the first version, puncheon shoulder has the shape of cylinder with a chamfer at its bottom. Puncheon is installed with a gap between upper edge of shoulder and punch holder in which a polyurethane washer is arranged. And it is also located between puncheon with shoulders and punch holder hole in order to make pivoting motion of puncheon possible. As per the second version, shoulder has the shape of sphere. Spherical shoulder is arranged in punch holder as per sliding fit. And it has a gap between puncheon and punch holder in order to make pivoting motion of the puncheon possible.

EFFECT: increasing stability owing to preventing frequent failures of puncheon at transition point of the puncheon proper to shoulder.

2 cl, 1 ex, 2 dwg