Patent US3513015A successfully refreshed from Google Patents.
Patent US3894337A successfully refreshed from Google Patents.
US3894337A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina razor blades
Assignee: Wilkinson Sword Ltd
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Filing: 1973-04-06
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Granted: 1975-07-15
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Expires: 1993-04-06
Abstract
Abstract The invention relates to razor blades and methods of manufacture thereof, the blades comprising a single crystal of alumina having a cutting edge thereon. The cutting edges can be formed by grinding of single crystals of alumina, preferably mounted to facilitate handling, in addition to or alternatively to dissolution or etching. The crystals are preferably grown in a shape approximating to the desired cross-section of blade to facilitate formation of the cutting edge. The alumina preferably has at the most a low content of impurities. Strengthening of the cutting edge can be effected by the implantation of large ions in and/or adjacent the cutting edge.
Inventors
- 👤 Frederick O Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:07
CPC Classifications
B; B26; B26B; B26B21/00; B26B21/54; B26B21/58
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
49 words
A RAZOR BLADE COMPRISING A SINGLE CRYSTAL OF ALUMINA HAVING A CUTTING EDGE THEREON, SAID SINGLE CRYSTAL HAVING LARGE IONS IN AND/OR ADJACENT THE SURFACE OF THE SINGLE CRYSTAL IN AN AMOUNT SUFFICIENT TO STRENGTHEN THE SURFACE OF THE CRYSTAL AT LEAST IN THE VICINITY OF THE CUTTING EDGE.
Claim 2
Dependent Claim
49 words
A RAZOR BLADE COMPRISING A SINGLE CRYSTAL OF ALUMINA HAVING A CUTTING EDGE THEREON, SAID SINGLE CRYSTAL HAVING LARGE IONS IN AND/OR ADJACENT THE SURFACE OF THE SINGLE CRYSTAL IN AN AMOUNT SUFFICIENT TO STRENGTHEN THE SURFACE OF THE CRYSTAL AT LEAST IN THE VICINITY OF THE CUTTING EDGE.
Claim 3
Dependent Claim
24 words
A razor blade according to claim 1, wherein the single crystal of alumina contains less than 3 X 10 3 atomic percent of impurities.
Claim 4
Dependent Claim
21 words
A razor blade according to claim 1, wherein the large ions have radii at least 50% larger than that of aluminum.
Claim 5
Dependent Claim
22 words
A razor blade according to claim 1, wherein the large ions are present in an amount of up to 3 atomic percent.
Claim 6
Dependent Claim
26 words
A razor blade according to claim 1, wherein the large ions are present to a depth of from 100 to 1,000 Angstroms below the said surface.
Claim 7
Dependent Claim
23 words
A razor blade according to claim 1, wherein the large ions are ions of metals in Group III A of the Periodic Table.
Claim 8
Dependent Claim
34 words
A razor blade according to claim 1, having at least one coating selected from the group consisting of alumina containing at the most a low concentration of impurities, metals, alloys and compounds of metals.
Claim 9
Dependent Claim
16 words
A razor blade according to claim 1, wherein the single crystal is mounted on a support.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |