Food warming apparatus
Abstract
Abstract A FOOD WARMER COMPRISING A TRAY PORTION HAVING SEVERAL COMPARTMENTS MOUNTS A HEATER ASSEMBLY IN HEAT TRANSFER RELATIONSHIP WITH SOME BUT NOT NECESSARILY ALL THE COMPARTMENTS. THE HEATER ASSEMBLY COMPRISES A HEAT TRANSFER PLATE OF THERMALLY AND ELECTRICALLY CONDUCTIVE MATERIAL TO WHICH IS SECURED A WAFER OF POSITIVE TEMPERATURE COEFFICIENT OF RESISTANCE MATERIAL. THE WAFER IS PROVIDED WITH AN ELECTRICALLY CONDUCTIVE COATING ON ITS TWO OPPOSITE FACES. AN ELECTRICALLY CONDUCTIVE SPRING IS MOUNTED BY AN EYELET ON A SAUCER-LIKE COVER OF ELECTRICALLY INSULATIVE MATERIAL. THE SPRING IS BIASED INTO ELECTRICAL CONTACT WITH THE WAFER WITH THE COVER CLAMPED IN PLACE ON THE HEAT TRANSFER PLATE BY A PLURALITY OF TABS. ELECTRICAL CONNECTION IS MADE TO THE HEAT TRANSFER PLATE AND TO THE EYELET TO PROVIDE A CURRENT PATH THROUGH THE WAFER. A RING OF HEAT SHRINKABLE MATERIAL IS SHRUNK AROUND THE PERIPHERY OF THE WAFER TO INCREASE THE EFFECTIVE ELECTRICAL DISTANCE BETWEEN THE TWO FACES OF THE WAFER.
Inventors
- 👤 Y Ting
Bibliographic Details
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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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |