Patent US3929475A successfully refreshed from Google Patents.
US3929475A
Expired / Lapsed
US
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Tarnish resistant silver based dental casting alloy having superior improved ductility and work hardening characteristics
Assignee: Williams Gold Refining Co Inc
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Filing: 1974-08-05
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Granted: 1975-12-30
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Expires: 1994-08-05
Abstract
Abstract An alloy comprising 10-60% Pd, 0.2-10% of at least one member of the group consisting of Cr, Fe, In, Sn and Zn, the balance silver having improved tarnish resistance meeting the Vickers hardness requirements of the American Dental Association Specification 5 for dental castings, which has superior ductility and work hardening characteristics.
Inventors
- 👤 Clyde E Ingersoll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:41
CPC Classifications
C; C22; C22C; C22C5/00; C22C5/06; A; A61; A61K; A61K6/00; A61K6/80; A61K6/84; A61K6/844
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
29 words
AN ALLOY CONSISTING ESSENTIALLY OF ABOUT 15-30% PD, ABOUT 0.2-10% OF AN ELEMENT OF THE GROUP CONSISTING OF CR, FE, AND IN AND MIXTURES THEREOF AND THE BALANCE AG.
Claim 2
Dependent Claim
29 words
AN ALLOY CONSISTING ESSENTIALLY OF ABOUT 15-30% PD, ABOUT 0.2-10% OF AN ELEMENT OF THE GROUP CONSISTING OF CR, FE, AND IN AND MIXTURES THEREOF AND THE BALANCE AG.
Claim 3
Dependent Claim
21 words
The alloy of claim 1 wherein the content of the element of the group is about 0.5-10% and the balance Ag.
Claim 4
Dependent Claim
18 words
The alloy of claim 1 consisting essentially of about 23.5% Pd, about 1% Fe and the balance Ag.
Claim 5
Dependent Claim
18 words
The alloy of claim 1 consisting essentially of about 25% Pd, about 3.5% In and the balance Ag.
Claim 6
Dependent Claim
24 words
The alloy of claim 1 consisting essentially of about 24.25% Pd, about 0.75% Fe, about 0.9% Sn, about 6% Zn and the balance Ag.
Claim 7
Dependent Claim
24 words
The alloy of claim 1 further including from about 0.2-10% of an element of the group consisting of Sn and Zn and mixtures thereof.
References Cited (Backward Citations)
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US1999866A
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US2070271A
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US2222544A
Cited
US2773561A
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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) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |