Patent US5666138A successfully refreshed from Google Patents.
Patent US4296295A successfully refreshed from Google Patents.
US4296295A
Expired / Lapsed
US
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Induction heating coil
Assignee: Panasonic Holdings Corp
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Filing: 1980-03-25
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Granted: 1981-10-20
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Expires: 2000-03-25
Abstract
Abstract An improved flat induction heating coil for a cooking apparatus of the type in which an electrically conductive cooking utensil is heated according to the principle of electromagnetic induction. To provide a substantially uniform magnetic flux density distribution in the induction coil constituting a part of the cooking apparatus and, hence, a uniform temperature distribution across the bottom of the cooking utensil, a refractory insulating material is wound adjacent inner turns of the coil to provide a comparatively larger winding pitch for said inner turns than for outer turns. This arrangement makes for a flattened temperature profile and eliminates an uneven cooking of food.
Inventors
- 👤 Mitsuyuki Kiuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:46
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/10; H05B6/12; H05B6/1209; H05B6/1245; H05B6/1281; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
115 words
A flat spiral wound induction heating coil of inner and outer pitch for a cooking appliance of the induction heating type which comprises a coil winding of litz wire having inner and outer turns, the outer turns being directly adjacent with each other and having a substantially uniform pitch, and a strip of electrically insulating material which is wound along between and adjacent to only said inner turns of said coil winding of litz wire so as to provide a comparatively larger, substantially uniform winding pitch for said inner turns of litz wire than the pitch of said outer turns thereof and thereby providing a uniform temperature distribution across the bottom of the cooking appliance.
Claim 2
Dependent Claim
115 words
A flat spiral wound induction heating coil of inner and outer pitch for a cooking appliance of the induction heating type which comprises a coil winding of litz wire having inner and outer turns, the outer turns being directly adjacent with each other and having a substantially uniform pitch, and a strip of electrically insulating material which is wound along between and adjacent to only said inner turns of said coil winding of litz wire so as to provide a comparatively larger, substantially uniform winding pitch for said inner turns of litz wire than the pitch of said outer turns thereof and thereby providing a uniform temperature distribution across the bottom of the cooking appliance.
Claim 3
Dependent Claim
35 words
A flat induction heating coil as set forth in claim 1 wherein the winding of said insulating material has a diameter not more than about one-half of the outside diameter of the induction heating coil.
Claim 4
Dependent Claim
30 words
A flat induction heating coil as set forth in claim 1 wherein said insulating material is made of a member selected from the group consisting of glass, asbestos and resin.
Claim 5
Dependent Claim
23 words
An induction heating coil as set forth in claim 1 wherein said insulating material and litz wire are substantially equal in outer diameter.
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) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |