US4629843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction cooking apparatus having a ferrite coil support
Assignee: TDK Corp
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Filing: 1985-04-03
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Granted: 1986-12-16
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Expires: 2005-04-03
Abstract
Abstract An induction cooking apparatus or a ceramics hob which heats conductive food and/or a conductive pan through hysteresis loss and/or eddy current loss by exciting a coil with high frequency power, comprises a casing, a coil mounted on a coil support, and an insulation cover plate between the coil and food to be cooked. The coil support is made of ferro-magnetic material of mixture of insulation resin and ferrite powder which occupies 75-85 weight %, instead of a prior mere insulation resin so that no flux leaks below the coil support. Preferably, the coil support has a plurality of longitudinal ferrite ribs extending radially under the coil support, and still preferably, the coil support has a plurality of holes at the central portion of the same so that permeability at the central portion is essentially smaller than that at the outer portion to provide uniform flux.
Inventors
- 👤 Namio Kato
- 👤 Tadao Takeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:08
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/10; H05B6/12; H05B6/1209; H05B6/1245; H05B6/1254; H05B2206/00; H05B2206/02; H05B2206/022; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
114 words
An induction cooking apparatus comprising a casing, a coil support mounted in the casing, an induction coil located on an upper plane of the coil support and being energized by high frequency power, and an insulation plate covering in the casing to provide a support for a load; characterized in that said coil support is essentially a flat disc made of a mixture of heat-resistive insulation resin and ferrite powder so that the weight ratio of ferrite powder to mixture is in the range between 75% and 85%; and wherein said coil support has a non-uniform permeability so that the permeability at a center portion is essentially less than that at an outer portion.
Claim 2
Dependent Claim
114 words
An induction cooking apparatus comprising a casing, a coil support mounted in the casing, an induction coil located on an upper plane of the coil support and being energized by high frequency power, and an insulation plate covering in the casing to provide a support for a load; characterized in that said coil support is essentially a flat disc made of a mixture of heat-resistive insulation resin and ferrite powder so that the weight ratio of ferrite powder to mixture is in the range between 75% and 85%; and wherein said coil support has a non-uniform permeability so that the permeability at a center portion is essentially less than that at an outer portion.
Claim 3
Dependent Claim
23 words
An induction cooking apparatus according to claim 1, wherein said resin is one selected from an unsaturated polyester resin and a phenol resin.
Claim 4
Dependent Claim
30 words
An induction cooking apparatus according to claim 1, wherein said coil support has a plurality of longitudinal ribs made of ferrite extending radially on a bottom plane of the support.
Claim 5
Dependent Claim
27 words
An induction cooking apparatus according to claim 3, wherein each of said ribs has a width larger than 5 mm and a height larger than 2 mm.
Claim 6
Dependent Claim
23 words
An induction cooking apparatus according to claim 3, wherein each of said ribs is fixed in a slit provided in the coil support.
Claim 7
Dependent Claim
19 words
An induction cooking apparatus according to claim 3, wherein each of said ribs is adhered on the coil support.
Claim 8
Dependent Claim
19 words
An induction cooking apparatus according to claim 3 wherein each of said ribs is integral with the coil support.
Claim 9
Dependent Claim
20 words
An induction cooking apparatus according to claim 3, wherein the number of ribs is equal to or larger than 4.
Claim 10
Dependent Claim
22 words
An induction cooking apparatus according to claim 3, wherein the Curie point of each of the ribs differs from one to another.
Claim 11
Dependent Claim
25 words
An induction cooking apparatus according to claim 9, wherein the Curie point of said ribs is in the range between 100° C. and 250° C.
Claim 12
Dependent Claim
43 words
An induction cooking apparatus according to claim 10, including detection means for detecting the magnetic nature of a rib and located close to said rib so as to detect whether or not the temperature of said rib is higher than the Curie point.
Claim 13
Dependent Claim
20 words
An induction cooking apparatus according to claim 1, wherein said coil support has a Curie point higher than 150° C.
Claim 14
Dependent Claim
19 words
An induction cooking apparatus according to claim 1, wherein said coil support has an initial permeability larger than 7.
Claim 15
Dependent Claim
21 words
An induction cooking apparatus according to claim 1, wherein said coil support has an intrinsic resistance larger than 10 4 ohms-cm.
Claim 16
Dependent Claim
24 words
An induction cooking apparatus according to claim 1, wherein said coil support has a plurality of openings at a center portion of the support.
Claim 17
Dependent Claim
19 words
An induction cooking apparatus according to claim 15, wherein said openings are through holes each provided between ferrite ribs.
Claim 18
Dependent Claim
17 words
An induction cooking apparatus according to claim 16, wherein each of said holes is a circular hole.
Claim 19
Dependent Claim
17 words
An induction cooking apparatus according to claim 16, wherein each of said holes is a longitudinal slit.
Claim 20
Dependent Claim
20 words
An induction cooking apparatus according to claim 16, wherein each of said holes is in the shape of an ellipse.
Claim 21
Dependent Claim
18 words
An induction cooking apparatus according to claim 16, wherein each of said holes is in a sector shape.
Claim 22
Dependent Claim
127 words
An induction cooking apparatus comprising a casing, a coil support mounted in the casing, an induction coil located on an upper plane of the coil support and being energized by high frequency power, and an insulation plate covering the casing to provide a support for a load; characterized in that said coil support is essentially a flat disc made of a mixture of heat-resistive insulation resin and ferrite powder so that the weight ratio of ferrite powder to mixture is in the range between 75% ad 85: and wherein said ferrite powder is a mixed ferrite having the composition: Fe 2 O 3 : 54-62 mol %, M n O: 23-33 mol %, Z n O: 9-20 mol %, M g O: more than 0.1 mol %.
Claim 23
Dependent Claim
127 words
An induction cooking apparatus comprising a casing, a coil support mounted in the casing, an induction coil located on an upper plane of the coil support and being energized by high frequency power, and an insulation plate covering the casing to provide a support for a load; characterized in that said coil support is essentially a flat disc made of a mixture of heat-resistive insulation resin and ferrite powder so that the weight ratio of ferrite powder to mixture is in the range between 75% ad 85: and wherein said ferrite powder is a mixed ferrite having the composition: Fe 2 O 3 : 54-62 mol %, M n O: 23-33 mol %, Z n O: 9-20 mol %, M g O: more than 0.1 mol %.
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) | 1989-12-15 | 1990-06-16 | 1990-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-15 | 1994-06-16 | 1994-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-15 | 1998-06-16 | 1998-12-16 | $7700.00 | Window Closed / Lapsed |