US2919180A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noncrumbling eraser composed of rubber, polyisobutylene and an abrasive material
Assignee: MRS NAOMI BURROWS
•
Filing: 1957-02-14
•
Granted: 1959-12-29
•
Expires: 1977-02-14
Abstract
No abstract record available.
Inventors
- 👤 Charles L Smith
- 👤 Benson G Brand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:19
CPC Classifications
B; B43; B43L; B43L19/00; B43L19/0025; C; C08; C08L; C08L7/00; C08L23/00; C08L23/02; C08L23/18; C08L23/20; C08L23/22
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
63 words
A NONCRUMBLING ERASER OF A CURED NATURAL RUBBER COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 100 PARTS BY WEIGHT OF NATURAL RUBBER, FROM 30 TO 80 PARTS BY WEIGHT PF POLYISOBYTYLENE HAVING A MOLECULAR WEIGHT NOT GREATER THAN 40,000, AND FROM 60 TO 240 PARTS BY WEIGHT OF A MINERAL ABRASIVE MATERIAL POSSESSING A HARDNESS OF FROM 7 TO 9 ON MOHS'' SCALE OF HARDNESS.
Claim 2
Dependent Claim
63 words
A NONCRUMBLING ERASER OF A CURED NATURAL RUBBER COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 100 PARTS BY WEIGHT OF NATURAL RUBBER, FROM 30 TO 80 PARTS BY WEIGHT PF POLYISOBYTYLENE HAVING A MOLECULAR WEIGHT NOT GREATER THAN 40,000, AND FROM 60 TO 240 PARTS BY WEIGHT OF A MINERAL ABRASIVE MATERIAL POSSESSING A HARDNESS OF FROM 7 TO 9 ON MOHS'' SCALE OF HARDNESS.
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) | 1962-12-28 | 1963-06-29 | 1963-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-12-28 | 1967-06-29 | 1967-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-12-28 | 1971-06-29 | 1971-12-29 | $7700.00 | Window Closed / Lapsed |