公开(公告)号：US3581538A

公开(公告)日：1971-06-01

申请号：US3581538D

申请日：1969-06-17

Applicant: CEFILAC

Inventor： ASARI AKIRA ,  IIMURO YUZURU

IPC: B21J5/00 ,  B21J9/04 ,  B21B45/02 ,  B21B31/02

CPC classification number: B21J9/04

Abstract: A piercing tool for piercing holes in large metal blocks comprising two distinct members. The shaft transmitting to the tool the force of the piercing press has rigidly secured and axially aligned to its end an axial member of smaller diameter than the shaft. A ring-shaped member having a diameter equal to that of the hole to be formed is annularly positioned about the axial member and is detachably mounted to the assembly made up of the shaft and axial member. After the hole has been pierced, the ring-shaped member is detached from that assembly as the tool is withdrawn through the hole in the metal billet.