Patent US3629030A successfully refreshed from Google Patents.
US3629030A
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Method for forming a mandrel and fabricating a duct thereabout
Assignee: ALVIN G ASH
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Filing: 1968-06-12
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Granted: 1971-12-21
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Expires: 1988-06-12
Abstract
Abstract A method of forming a plastic duct of irregular configuration employing an elastic mandrel that is used repeatedly in the manufacture of a plurality of similarly shaped ducts. The mandrel is contracted for separating it from a finished duct and is expanded for fabricating a subsequent duct. The mandrel is formed by placing an inflatable tube or plurality of tubes in a mold with a quantity of uncured elastic material, inflating the tube or tubes, and curing the elastic material to form the composite inflatable mandrel. The tube or tubes have a limited expanded cross section and the mandrel can be inflated to the same size and shape at any time by fully inflating the tube or tubes.
Inventors
- 👤 Alvin G Ash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:22
CPC Classifications
B; B29; B29C; B29C33/00; B29C33/44; B29C33/48; B29C33/50; B29C33/505; B29C70/00; B29C70/04; B29C70/28; B29C70/40; B29C70/42; B29C70/44; B29C70/446; B29C43/00; B29C43/02; B29C43/10; B29C43/12; B29L; B29L2023/00; B29L2023/22; Y; Y10; Y10S; Y10S425/00; Y10S425/019
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
29 words
The method of claim 1 wherein said chamber is formed by a plurality of tubes connected together to form a honeycomb structure of fixed limited cross section when inflated.
Claim 2
Dependent Claim
29 words
The method of claim 2 including the step of separating said elastic mandrel from said female mold by creating a vacuum in said internal chamber to contract said mandrel.
References Cited (Backward Citations)
US2289990A
Cited
US2739350A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |