| (19) |
 |
|
(11) |
EP 0 181 203 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
21.01.1987 Bulletin 1987/04 |
| (43) |
Date of publication A2: |
|
14.05.1986 Bulletin 1986/20 |
| (22) |
Date of filing: 06.11.1985 |
|
|
| (84) |
Designated Contracting States: |
|
DE FR GB |
| (30) |
Priority: |
06.11.1984 GB 8428064
|
| (71) |
Applicant: BRITISH AEROSPACE PUBLIC LIMITED COMPANY |
|
() |
|
| (72) |
Inventors: |
|
- Stephen, David British Aerospace P.L.C.
()
- Mansbridge, Martin Henry British Aerospace P.L.C.
()
|
|
| |
|
| (54) |
Forming complex hollow sectioned structural members |
(57) A method is described of forming relatively complex I-sectioned tubular beam from
relatively simple O-sectioned tubular stock either seamed or seamless provided that
the material of the stock is superplastically deformable. The 0-sectioned stock is
sealed and filled with inert gas, heated to superplastic forming temperature and,
in one embodiment, is placed in a mould which has regions inwardly movable to compress
the stock into a desired shape, the gaseous pressure thus formed internally of the
sealed stock causing the material of the stock to conform to the final interior shape
of the mould. In a further embodiment the sealed, filled and heated stock is urged
axially through a die which compresses the stock and is again constrained to conform
with the final interior shape of the die by virtue of its internal gaseous pressure.