US2721372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incandescible cathodes
Assignee: US Philips Corp
•
Filing: 1951-06-30
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Granted: 1955-10-25
•
Expires: 1971-06-30
Abstract
No abstract record available.
Inventors
- 👤 Levi Roberto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:54
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/04; H01J9/042; H01J9/047; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4981; Y10T29/49812
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
181 words
A METHOD OF MANUFACTURING A DISPENSER TYPE OF CATHODE WHICH COMPRISES FORMING TUNGSTEN POWDER INTO A BODY, SINTERING SAID BODY AT A TEMPERATURE ABOVE 1000* C. AND HIGHER THAN THE VOLATILIZATION TEMPERATURE OF A FILLER METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, GOLD, SILVER, AND ALLOYS THEREOF WITH WHICH THE BODY IS SUBSEQUENTLY IMPREGNATED TO FORM A COHERENT BODY HAVING A PREDETERMINED DENSITY AND POROSITY, THE THUS-FORMED TUNGSTEN BODY BEING SUBSTANTIALLY IN ITS FINAL SINTERED STATE, IMPREGNATING SAID BODY WITH SAID FILLER METAL, MACHINING SAID BODY TO FORM THE SAME INTO A BODY OF DESIRED SHAPE AND DIMENSIONS AND HAVING AN EMISSIVE SURFACE, VOLATILIZING ALL OF SAID IMPREGNANT METAL FROM SAID BODY IN A PROTECTIVE ATMOSPHERE WHICH WILL NOT REACT WITH TUNGSTEN AT A TEMPERATURE SUBSTANTIALLY LESS THAN SAID SINTERING TEMPERATURE TO LEAVE A SINTERED BODY FREE OF SAID IMPREGNANT METAL WITHOUT SUBSTANTIALLY ALTERING THE POROSITY AND DENSITY THEREOF, AND DISPOSING AT A POINT CONNECTED TO SAID SURFACE ONLY THROUGH PORES OF THE BODY A SUPPLY OF ALKALINE EARTH COMPOUNDS CAPBALE OF FURNISHING FREE ALKALINE EARTH METAL TO SAID SURFACE.
Claim 2
Independent Claim
181 words
A METHOD OF MANUFACTURING A DISPENSER TYPE OF CATHODE WHICH COMPRISES FORMING TUNGSTEN POWDER INTO A BODY, SINTERING SAID BODY AT A TEMPERATURE ABOVE 1000* C. AND HIGHER THAN THE VOLATILIZATION TEMPERATURE OF A FILLER METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, GOLD, SILVER, AND ALLOYS THEREOF WITH WHICH THE BODY IS SUBSEQUENTLY IMPREGNATED TO FORM A COHERENT BODY HAVING A PREDETERMINED DENSITY AND POROSITY, THE THUS-FORMED TUNGSTEN BODY BEING SUBSTANTIALLY IN ITS FINAL SINTERED STATE, IMPREGNATING SAID BODY WITH SAID FILLER METAL, MACHINING SAID BODY TO FORM THE SAME INTO A BODY OF DESIRED SHAPE AND DIMENSIONS AND HAVING AN EMISSIVE SURFACE, VOLATILIZING ALL OF SAID IMPREGNANT METAL FROM SAID BODY IN A PROTECTIVE ATMOSPHERE WHICH WILL NOT REACT WITH TUNGSTEN AT A TEMPERATURE SUBSTANTIALLY LESS THAN SAID SINTERING TEMPERATURE TO LEAVE A SINTERED BODY FREE OF SAID IMPREGNANT METAL WITHOUT SUBSTANTIALLY ALTERING THE POROSITY AND DENSITY THEREOF, AND DISPOSING AT A POINT CONNECTED TO SAID SURFACE ONLY THROUGH PORES OF THE BODY A SUPPLY OF ALKALINE EARTH COMPOUNDS CAPBALE OF FURNISHING FREE ALKALINE EARTH METAL TO SAID SURFACE.
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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) | 1958-10-24 | 1959-04-25 | 1959-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-24 | 1963-04-25 | 1963-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-24 | 1967-04-25 | 1967-10-25 | $7700.00 | Window Closed / Lapsed |