US4445026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical devices comprising PTC conductive polymer elements
Assignee: Littelfuse Inc
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Filing: 1980-07-10
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Granted: 1984-04-24
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Expires: 2000-07-10
Abstract
Abstract Electrical devices comprising a layer of a PTC conductive polymer and a sheet electrode in contact with each face of the PTC layer. The electrodes extend to the sides of the layer and the sides of the layer are concave, and this results in improved performance. Preferred devices are circuit control devices which protect a circuit from increases in current resulting from a fault.
Inventors
- 👤 Jack M. Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:28
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; H01C1/00; H01C1/14; H01C1/1406; H01C7/021; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24298
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
83 words
An electrical device which comprises (a) a layer of a conductive polymer composition which exhibits PTC behavior; (b) a first sheet electrode which contacts one face of said layer; and (c) a second sheet electrode which contacts the other face of said layer; wherein at least a part of each of said electrodes extends to a side of said layer which is concave adjacent the electrodes so that the angle between each electrode and the side of the layer is less than 80°.
Claim 2
Dependent Claim
83 words
An electrical device which comprises (a) a layer of a conductive polymer composition which exhibits PTC behavior; (b) a first sheet electrode which contacts one face of said layer; and (c) a second sheet electrode which contacts the other face of said layer; wherein at least a part of each of said electrodes extends to a side of said layer which is concave adjacent the electrodes so that the angle between each electrode and the side of the layer is less than 80°.
Claim 3
Dependent Claim
18 words
A device according to claim 1 wherein each of said electrodes substantially covers a face of said layer.
Claim 4
Dependent Claim
45 words
A device according to claim 2 wherein the side of said layer is concave around the whole of the periphery of said layer, so that at all points the angle between each of the electrodes and the side of the layer is less than 80°.
Claim 5
Dependent Claim
14 words
A device according to claim 3 wherein each of said electrodes is of metal.
Claim 6
Dependent Claim
18 words
A device according to claim 3 wherein each of said electrodes extends beyond the periphery of said layer.
Claim 7
Dependent Claim
18 words
A device according to claim 3 which has a resistance at 23° C. of less than 25 ohms.
Claim 8
Dependent Claim
47 words
A device according to claim 3 wherein said layer has a substantially constant thickness of 0.025 to 0.7 cm and a cross-sectional area of 0.25 to 20 cm 2 and is composed of a conductive polymer having a resistivity at 23° C. of less than 10 ohm.cm.
Claim 9
Dependent Claim
25 words
A device according to claim 3 wherein the minimum cross-sectional area of said layer is 0.6 to 0.96 times its cross-sectional area adjacent the electrodes.
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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) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |