Blanking die assembly with at least one device for differentially rotating the blanking unit

A sheet metal blanking die assembly, comprising:

• a lower part,
• an upper part and
• guide columns, the guide columns being arranged to maintain the parts aligned during movement of the upper part relative to the lower part in order to close or open the die assembly or to blank the sheet metal to obtain relative blanked laminations,
• the die upper part and lower part of the die assembly comprising flat parallel mutually opposing upper and lower horizontal portions, the lower flat portion being adapted to receive the sheet metal, the upper flat portion comprising a plurality of punches which project downwards from the upper flat portion at the moment of blanking when, by the action of a press, the die assembly is closed onto said flat lower portion, blanking recesses being provided to receive respective punches, the assembly further comprising at least one differential rotation device for a blanking unit positioned to correspond with at least one blanking position, said differential rotation device comprising:
• a punch holder housed in an upper part of the die assembly, the punch holder comprising a plurality of through seats adapted to house punches via their heads;
• a guide means housed in a punch guide plate, housed in a lower portion of the upper part of the die assembly, said guide means being positioned to correspond with the punch holder and comprising a plurality of through recesses corresponding to said seats of the punch holder, said recesses being adapted to slidingly house the punches;
• and
• a die housed in a die plate positioned in the lower part of the die assembly, said die presenting in positions corresponding with said seats of the die a plurality of recesses to house the punches during a sheet metal blanking stage,
• wherein said punch holder, guide and die:
• form a blanking unit adapted to rotate about an X axis within said upper part and lower part of the die assembly;
• present respectively further seats to house centring means, and
• are able to rigidly rotate mutually by way of said centring means.