Patent US3671955A successfully refreshed from Google Patents.
US3671955A
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US
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Lamp failure detection circuit
Assignee: Eaton Corp
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Filing: 1970-03-30
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Granted: 1972-06-20
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Expires: 1990-03-30
Abstract
Abstract A circuit for monitoring for the failure of one or more lamps in an indicator device, a segment type readout device, or the like. Upon failure of a lamp, a silicon controlled rectifier or a transistor switch is biased into a conducting state to energize either a back-up lamp or a warning lamp. A circuit may be included to flash either the back-up lamp, the warning lamp or a third indicator lamp in response to detecting the failure of a lamp. When the circuit monitors a plurality of lamps, the circuit can be adapted to deactivate all lamps upon detecting the failure of any of the lamps.
Inventors
- 👤 Ali Asghar Malekzadeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:18
CPC Classifications
H; H05; H05B; H05B39/00; H05B39/10; H05B39/105
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
99 words
A circuit for detecting and indicating the failure of any of a plurality of incandescent lamps comprising, in combination, an indicator lamp, a plurality of normally nonconducting electronic switches, means connecting said switches in parallel with each other and in series with said indicator lamp whereby closure of any of said switches energizes said indicator lamp, means for energizing a different one of said switches in response to a failure of a different one of the incandescent lamps, and means responsive to the energization of any of said switches for disconnecting power from selected ones of the incandescent lamps.
Claim 2
Dependent Claim
99 words
A circuit for detecting and indicating the failure of any of a plurality of incandescent lamps comprising, in combination, an indicator lamp, a plurality of normally nonconducting electronic switches, means connecting said switches in parallel with each other and in series with said indicator lamp whereby closure of any of said switches energizes said indicator lamp, means for energizing a different one of said switches in response to a failure of a different one of the incandescent lamps, and means responsive to the energization of any of said switches for disconnecting power from selected ones of the incandescent lamps.
Claim 3
Dependent Claim
46 words
A circuit for detecting and indicating the failure of any of a plurality of incandescent lamps, as defined in claim 1, and including means for simultaneously energizing all of the incandescent lamps and said indicator lamp for simultaneously testing the incandescent lamps and said indicator lamp.
Claim 4
Dependent Claim
33 words
A circuit for detecting and indicating the failure of any of a plurality of incandescent lamps, as defined in claim 1, and including switch means for selectively energizing each of the incandescent lamps.
Claim 5
Dependent Claim
33 words
A circuit for detecting and indicating the failure of any of a plurality of incandescent lamps, as defined in claim 1, wherein said disconnecting means disconnects power from all of the incandescent lamps.
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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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |