US3683995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a composite sand mold including recycling the land
Assignee: Individual
•
Filing: 1970-03-25
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Granted: 1972-08-15
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Expires: 1990-03-25
Abstract
Abstract A precision-type composite mold or core for foundry use comprising a body formed from relatively inexpensive coarse sand bonded with sodium silicate cured by reaction with CO2 and a relatively expensive facing integral with said body and composed of a lesser amount of relatively fine sand than the coarse sand of said body, said fine sand being bonded by a synthetic resin cured by reaction with an amine, at least said coarse sand and sodium silicate bond being recoverable following the use of the mold or core formed therefrom and reconstituted for further use to decrease the overall cost of making and using molds and cores of such type.
Inventors
- 👤 Lothar Robert Zifferer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:31
CPC Classifications
B; B22; B22C; B22C1/00; B22C1/16; B22C1/165; B22C9/00; B22C9/12; B22C9/123
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2748435A
Cited
US2873493A
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FR1121473A
Cited
US2861307A
Cited
US3131999A
Cited
US3309212A
Cited
US3318712A
Cited
US3447589A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |