Patent US3742420A successfully refreshed from Google Patents.
US3742420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective electrical feed through assemblies for enclosures for electrical devices
Assignee: Individual
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Filing: 1971-10-21
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Granted: 1973-06-26
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Expires: 1991-10-21
Abstract
Abstract A wafer of metallic oxide varistor material having a pair of opposed surfaces is provided with a plurality of apertures, each extending through the wafer from one opposed surface to the other opposed surface thereof. Each of the apertures are adapted to receive a respective conductive electrode of an electrical device and provide conductive contact between each of the electrodes and the wafer. The material has an alpha in excess of 10 when the current is of the current density range of 10 3 to 102 amperes per square centimeter. The proportions of the apertures of the wafer in contact with the electrodes are spaced to provide a current flow between a pair of electrodes which is low when normal operating voltages appear across the pair of electrodes and when voltages in excess of the normal voltage appear across the electrodes a rapidly decreasing impedance is presented by the wafer in accordance with the alpha of the material of the wafer thereby limiting the voltage across the electrodes.
Inventors
- 👤 J Harnden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:53
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/102; H05; H05K; H05K7/00; H05K7/02; H05K7/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
167 words
A protective pad for use with electrical devices comprising: a wafer of metallic oxide varistor material having a pair of opposed surfaces, a plurality of apertures in said wafer, each extending through said wafer from one opposed surface thereof, each of said apertures adapted to receive a respective conductive electrode of an electrical device and provide conductive contact of each of said electrodes with said wafer, said material having an essentially constant alpha in excess of 10 in the current density range of 10 3 to 102 per square centimeter, the portions of said apertures of said wafer in contact with said electrodes being spaced to provide a current flow between a pair of electrodes which is low when normal operating voltage appears across said pair of electrodes and when voltages in excess of normal voltage appears thereacross rapidly decreasing impedance is presented by said wafer in accordance with the alpha of the material of the body thereby limiting the voltage appearing between said pair of electrodes.
Claim 2
Dependent Claim
167 words
A protective pad for use with electrical devices comprising: a wafer of metallic oxide varistor material having a pair of opposed surfaces, a plurality of apertures in said wafer, each extending through said wafer from one opposed surface thereof, each of said apertures adapted to receive a respective conductive electrode of an electrical device and provide conductive contact of each of said electrodes with said wafer, said material having an essentially constant alpha in excess of 10 in the current density range of 10 3 to 102 per square centimeter, the portions of said apertures of said wafer in contact with said electrodes being spaced to provide a current flow between a pair of electrodes which is low when normal operating voltage appears across said pair of electrodes and when voltages in excess of normal voltage appears thereacross rapidly decreasing impedance is presented by said wafer in accordance with the alpha of the material of the body thereby limiting the voltage appearing between said pair of electrodes.
Claim 3
Dependent Claim
63 words
The combination of claim 1 in which one of said surfaces is provided with a pair of spaced conductive layers, each in conductive contact with a respective one of a pair of said electrodes, the distance between said layers along said one surface being set to obtain a desired normal operating point on the voltage versus current graph of one pair of electrodes.
Claim 4
Dependent Claim
68 words
The combination of claim 2 in which the other of said surfaces is provided with another pair of spaced conductive layers, each in conductive contact with a respective one of another pair of said electrodes, the distance between said other pair of layers along said other surface being set to obtain a desired normal operating point on the voltage versus current graphs of said other pair of electrodes.
Claim 5
Dependent Claim
162 words
In combination, a wafer of metallic oxide varistor material having a pair of opposed surfaces, a plurality of apertures in said wafer, each extending through said wafer from one opposed surface to the other opposed surface thereof, an electrical device having a plurality of electrodes, each of said electrodes extending through a respective one of said apertures and in conductive contact therewith, said material having an alpha in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter, the portions of said apertures of said wafer in contact with said electrodes being spaced to provide a current flow between a pair of electrodes which is low when normal operating voltage appears across said pair of electrodes and when voltages in excess of normal voltage appears thereacross rapidly decreasing impedance is presented by said wafer in accordance with the alpha of the material of the body thereby limiting the voltage appearing between said pair of electrodes.
Claim 6
Dependent Claim
162 words
In combination, a wafer of metallic oxide varistor material having a pair of opposed surfaces, a plurality of apertures in said wafer, each extending through said wafer from one opposed surface to the other opposed surface thereof, an electrical device having a plurality of electrodes, each of said electrodes extending through a respective one of said apertures and in conductive contact therewith, said material having an alpha in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter, the portions of said apertures of said wafer in contact with said electrodes being spaced to provide a current flow between a pair of electrodes which is low when normal operating voltage appears across said pair of electrodes and when voltages in excess of normal voltage appears thereacross rapidly decreasing impedance is presented by said wafer in accordance with the alpha of the material of the body thereby limiting the voltage appearing between said pair of electrodes.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |