PUNCHING DIE SET (VARIANTS) Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely punching die sets. SUBSTANCE: die set includes upper plate, punch holder, stripper, punch, lower plate with female die. Die set includes in addition upper insert having sector protrusions directed towards lower insert having sector protrusions directed towards upper insert. Sector protrusions of lower insert are radially shifted relative to sector protrusions of upper inserts. Sector protrusions of both inserts are mutually overlapped at alternation in lengthwise direction and they form seal with inner lengthwise cavity. Punch is arranged in inner cavity in such a way that it always engages with guiding sector protrusions of upper and lower inserts and with other inner surfaces of upper and lower inserts. EFFECT: enhanced strength of punch, possibility for punching extremely small holes. 3 cl, 4 dwg