Lamina stack having a plurality of outer perimeter configurations and an apparatus and method for manufacturing said stack

A rotor or stator made according to the method of stamping electric motor laminas from sheet stock material provided from a supply, the laminas each having a planar surface, in a die assembly having a selectively actuated punch and a choke barrel to form a stack of laminas in the choke barrel, the method comprising:

• a first step of guiding said sheet stock material through said die assembly;
• a second step of stamping a plurality of generally planar laminas from said sheet stock material with the selectively actuated punch, each of said laminas having an axis and an outer perimeter surface which are disposed substantially perpendicular to the plane of the lamina;
• each of said lamina outer perimeter surfaces defining one of a plurality of distinguishable predetermined outer perimeter configurations, a portion of each of said outer perimeter surfaces comprising a common choke surface for contacting said choke barrel;
• a third step of coaxially stacking said laminas in the choke barrel with said common choke surfaces being aligned to thereby form a stack of laminas having a plurality of outer perimeter configurations.

A die assembly for manufacturing a stack of laminas from sheet stock material, said die assembly comprising:

• a punching station;
• a stacking station;
• first means for guiding the sheet stock material to said punching station;
• a selectively actuable punch at said punching station for stamping generally planar laminas having one of a plurality of predetermined outer perimeter configurations, the laminas each having at least one common choke surface defining a portion of said outer perimeter configurations;
• a choke barrel at said stacking station for receiving and stacking the laminas with the common choke surfaces being aligned to thereby form a stack comprised of laminas having a plurality of outer perimeter configurations.

An apparatus for manufacturing electric motor parts from sheet stock material, said apparatus comprising:

• a selectively actuable punch for stamping generally planar laminas having a plurality of predetermined outer perimeter configurations, the outer perimeter configurations each being defined in part by at least one common choke surface;
• controller means coupled to said selectively actuable punch to control the stamping sequence of said selectively actuable punch;
• a choke barrel;
• and
• stacking means for stacking the laminas in said choke barrel with the common choke surfaces being aligned.

A method of manufacturing a laminated stack in a die assembly having means for guiding sheet stock material through the die assembly, stamping means and a choke barrel;

• said method comprising:
• a first step of stamping a plurality of generally planar laminas from said sheet stock material with the stamping means, each of said laminas having an outer perimeter surface defining one of a plurality of outer perimeter configurations, a portion of each of said outer perimeter surfaces comprising a common choke surface;
• and
• a second step of stacking said laminas in the choke barrel by aligning said common choke surfaces to thereby form a laminated stack.