US3573023A
Expired / Lapsed
US
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Methods for improving hardness and strength of ceramic materials
Assignee: Ingersoll Rand Co
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Filing: 1968-09-24
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Granted: 1971-03-30
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Expires: 1988-09-24
Abstract
Abstract METHODS FOR IMPROVING THE HARDNESS AND STRENGTH OF FRANGIBLE OR RELATIVELY BRITTLE MATERIALS, INVOLVING SURFACE DEFORMATION BY MECHANICAL MEANS TO ESTABLISH COMPRESSIVE STRESSES IN THE MATERIAL SURFACE.
Inventors
- 👤 David A Thomas
- 👤 David N French
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:05
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C03; C03B; C03B27/00; C03C; C03C23/00; C22; C22F; C22F1/00; B; B24; B24C; B24C1/00; B24C1/10; Y; Y02; Y02P; Y02P40/00; Y02P40/50; Y02P40/57
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |