US3584196A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic electric cooking appliance
Assignee: Panasonic Holdings Corp
•
Filing: 1969-11-06
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Granted: 1971-06-08
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Expires: 1989-11-06
Abstract
Abstract An automatic electric cooking appliance comprises a cooking pot, a heating unit consisting of a metallic alloy heater connected in series with a resistor having a positive temperature coefficient of resistance (PTC resistor), and a bimetallic diaphragm for changing the thermal coupling between the PTC resistor and the cooking pot. The heating unit first heats the food for cooking, and then the bimetallic diaphragm abruptly lifts the cooking pot to reduce the thermal coupling and raise the temperature of the PTC resistor. This causes an abrupt increase in resistance and thereby a decrease in current flowing through the heating unit. Thus, only low wattage is used for warming the cooked food.
Inventors
- 👤 Eisuke Kurokawa
- 👤 Hiromu Sasaki
- 👤 Shigeru Hayakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:17
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1919; G05D23/192; G05D23/275
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
105 words
An automatic electric cooking appliance comprising a cooking pot of metallic heat conductive material, an outer support for said pot, a heating unit thermally coupled to said pot and including a metallic alloy heater and a resistor positioned in the space between said support and said pot, said resistor having a positive temperature coefficient of resistance and connected in series with said metallic alloy heater, and a bimetallic diaphragm means positioned in said space for lifting said pot upon completion of cooking in response to a temperature change to change the thermocoupling between the PTC resistor and said cooking pot, thereby causing a current switching.
Claim 2
Dependent Claim
105 words
An automatic electric cooking appliance comprising a cooking pot of metallic heat conductive material, an outer support for said pot, a heating unit thermally coupled to said pot and including a metallic alloy heater and a resistor positioned in the space between said support and said pot, said resistor having a positive temperature coefficient of resistance and connected in series with said metallic alloy heater, and a bimetallic diaphragm means positioned in said space for lifting said pot upon completion of cooking in response to a temperature change to change the thermocoupling between the PTC resistor and said cooking pot, thereby causing a current switching.
Claim 3
Dependent Claim
24 words
An automatic electric cooking appliance as claimed in claim 1, wherein said PTC resistor is a semiconductive barium and lead titanate solid solution ceramic.
References Cited (Backward Citations)
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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) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |