| ONES CO., LTD. Patent applications |
| Patent application number | Title | Published |
|---|
| 20110174127 | METHOD FOR PRESS PUNCHING A HOLE IN SHEET METAL AND PRESS DIE - A punch unit for a press die for punching a hole in sheet metal includes: a piercing punch provided with a sharp projection; a plunger for pressing the piercing punch; a cylinder for supporting the piercing punch and the plunger slidably in a punching direction; and a coil spring for retracting the piercing punch and the plunger. Also disclosed are a press die for punching a hole in sheet metal and a punching method using the punch unit. | 07-21-2011 |
| 20100212388 | DIE FOR PUNCHING SHEET METAL AND SHEET METAL PUNCHING APPARATUS HAVING THE DIE - A sheet metal punching apparatus | 08-26-2010 |
