ROTARY PIERCER WORKING TOOLS Russian patent published in 2013 - IPC B21B19/04 

FIELD: process engineering.

SUBSTANCE: rotary pierce working rolls comprises rolls with piercing cone and reeling mandrel separated by wafer core, rules and mandrel extending beyond said wafer core. Better biller reduction and decreased wear are ensured by making circular groove at mandrel working cone in length not exceeding 3/4 of working cone length from mandrel gaging section start cross-section and in depth of 1.5-12.0% of mandrel diameter. Said circular recess can be formed by intersection of surface conical sections equal in height and with bidirectional taper and equidistant surface of the mandrel working cone. Note here that cross-section corresponding to mandrel gaging part start has straight cone section while at mandrel nose it has inverse cone section. Said circular recess can be formed by intersection of inverse cone surfaces and mandrel working cone at nose and connection of circular recess with mandrel working cone in cross-section corresponding to mandrel gaging section.

EFFECT: better quality of cupped blanks.

8 cl, 7 dwg