Stretch form die
US4576030A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1983 |
| Grant date | Mar 18, 1986 |
| Priority date | — |
| Expiry date | Aug 31, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21D22/02
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An apparatus and method relating to an improved die for homogeneously stretch forming sheet metal in standard sized presses without also drawing the sheet metal. The die is comprised of complementary male and female die halves moveable between open and closed positions, and a blank holder member moveable between open and closed positions relative to the female die half. A pair of grippers having mutually facing surfaces is carried by the female die half and the blank holder member. One of the gripper surfaces defines exactly two rectangular shaped beads which extend entirely around the circumference of the male and female die halves, while the other of the gripper surfaces is flat. The beads are equally spaced apart along their lengths and each includes a pair of relatively sharp edges for biting into the sheet metal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.