Method and device for forming a sheet-metal blank in particular in order to make a cathode ray tube mask, and cathode ray tube mask obtained according to this method
US5119658A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 17, 1990 |
| Grant date | Jun 9, 1992 |
| Priority date | — |
| Expiry date | Dec 17, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/142
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The subject of the present invention is a method for forming a sheet-metal blank (1), in particular in order to make a cathode ray tube mask, on a press, according to which the central part (1a) of the sheet-metal blank (1) is formed with a specified curvature under the effect of a punch (20) which deforms, in a mould (12), the upper die part (14), the load exerted on the punch (20) being distributed over the entire surface of the base (24) of the punch (20), and according to which, after the curving of the central part of the sheet-metal blank, a mechanical action is exerted on a peripheral forming member (30) so as to apply pressure to a ring (36), the ring (36) is deformed and presses against the free part (1b) of the sheet-metal blank (1) in order first to effect a controlled bending of the said free part, and then the said free part (1b) is applied, still under the action of the ring (36), along the side walls of the punch (20) in order to form the flanged edge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.