US2809140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating tungsten filaments
Assignee: General Electric Co
•
Filing: 1953-11-06
•
Granted: 1957-10-08
•
Expires: 1973-11-06
Abstract
No abstract record available.
Inventors
- 👤 Thomas F Smeaton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:13
CPC Classifications
H; H01; H01K; H01K3/00; H01K3/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
71 words
THE METHOD OF TREATING COILED TUGSTEN WIRE FILAMENTS FOR ELECTRIC LAMPS AND THE LIKE SAID METHOD COMPRISING WINDING THE WIRE INTO A HELIX ON A MANDREL WIRE HEAT-TREATING THE COIL FILAMENT TO REMOVE THE STRAIN INDUCED BY THE COILING OPERATION IN A CONTROLLED REDUCING ATMOSPHERE OF HYDROGEN AT ABOUT 1500*C. FOR ABOUT 10 TO 15 MINUTES AND IMMEDIATELY THEREAFTER, WITHOUT EXPOSURE TO AIR, COOLING THE FILAMENTS IN AN ATMOSPHERE OF NITROGEN.
Claim 2
Independent Claim
71 words
THE METHOD OF TREATING COILED TUGSTEN WIRE FILAMENTS FOR ELECTRIC LAMPS AND THE LIKE SAID METHOD COMPRISING WINDING THE WIRE INTO A HELIX ON A MANDREL WIRE HEAT-TREATING THE COIL FILAMENT TO REMOVE THE STRAIN INDUCED BY THE COILING OPERATION IN A CONTROLLED REDUCING ATMOSPHERE OF HYDROGEN AT ABOUT 1500*C. FOR ABOUT 10 TO 15 MINUTES AND IMMEDIATELY THEREAFTER, WITHOUT EXPOSURE TO AIR, COOLING THE FILAMENTS IN AN ATMOSPHERE OF NITROGEN.
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) | 1960-10-07 | 1961-04-08 | 1961-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-10-07 | 1965-04-08 | 1965-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-10-07 | 1969-04-08 | 1969-10-08 | $7700.00 | Window Closed / Lapsed |