US3691440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overspeed detector
Assignee: United States Steel Corp
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Filing: 1971-04-16
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Granted: 1972-09-12
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Expires: 1991-04-16
Abstract
Abstract A shaft overspeed detector has a shaft-mounted strip which periodically interrupts a light beam falling on a photosensitive cell as the shaft rotates. An electrical circuit provides a timebased pulse for each interruption and if a second interruption occurs before the time-based pulse has risen to a cutoff level, a speed controller is activated.
Inventors
- 👤 Logan D Haddock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:50
CPC Classifications
G; G01; G01P; G01P1/00; G01P1/07; G01P1/08; G01P1/10; G01P1/106; B; B23; B23Q; B23Q15/00; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/917; Y10S388/918
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
349 words
Apparatus for detecting overspeed of a rotating shaft comprising a source of light; a photosensitive cell arranged to receive light from said source; a light interrupter strip mounted on said shaft and adapted to interrupt the passage of light from said source to said cell for a predetermined period of angular movement of said shaft; a source of direct current; a first capacitor; a first circuit means connected to said cell, said direct current source and said capacitor whereby when light from said source is received by said cell said first capacitor charges and when light is not received by said cell said first capacitor discharges thereby providing a first pulse; a first silicon controlled rectifier having a cathode connected to said source of direct current and a gate connected to said first circuit means; a second capacitor; a constant current source connected to said second capacitor, said source of direct current and the anode of said first silicon controlled rectifier; second circuit means connected to said first silicon controlled rectifier, said second capacitor and said direct current source and responsive to the occurrence of each of said first pulses for charging said second capacitor at a predetermined rate to a predetermined magnitude and for discharging said second capacitor when the charge on said second capacitor reaches said predetermined magnitude thereby providing a second pulse; a second silicon controlled rectifier having a cathode and an anode connected to said source of direct current and a gate connected to said second circuit means whereby said second silicon controlled rectifier is turned on when said second capacitor discharges; a third capacitor connected between the anode of said first silicon controlled rectifier and the anode of said second silicon controlled rectifier whereby when one of said silicon controlled rectifiers is turned on, the other is turned off; an indicator; and means connected to said first circuit means, said second circuit means and said indicator and responsive to the occurrence of one of said first pulses occurring while one of said second pulses is rising to said predetermined magnitude for activating saiD indicator.
Claim 2
Dependent Claim
349 words
Apparatus for detecting overspeed of a rotating shaft comprising a source of light; a photosensitive cell arranged to receive light from said source; a light interrupter strip mounted on said shaft and adapted to interrupt the passage of light from said source to said cell for a predetermined period of angular movement of said shaft; a source of direct current; a first capacitor; a first circuit means connected to said cell, said direct current source and said capacitor whereby when light from said source is received by said cell said first capacitor charges and when light is not received by said cell said first capacitor discharges thereby providing a first pulse; a first silicon controlled rectifier having a cathode connected to said source of direct current and a gate connected to said first circuit means; a second capacitor; a constant current source connected to said second capacitor, said source of direct current and the anode of said first silicon controlled rectifier; second circuit means connected to said first silicon controlled rectifier, said second capacitor and said direct current source and responsive to the occurrence of each of said first pulses for charging said second capacitor at a predetermined rate to a predetermined magnitude and for discharging said second capacitor when the charge on said second capacitor reaches said predetermined magnitude thereby providing a second pulse; a second silicon controlled rectifier having a cathode and an anode connected to said source of direct current and a gate connected to said second circuit means whereby said second silicon controlled rectifier is turned on when said second capacitor discharges; a third capacitor connected between the anode of said first silicon controlled rectifier and the anode of said second silicon controlled rectifier whereby when one of said silicon controlled rectifiers is turned on, the other is turned off; an indicator; and means connected to said first circuit means, said second circuit means and said indicator and responsive to the occurrence of one of said first pulses occurring while one of said second pulses is rising to said predetermined magnitude for activating saiD indicator.
Claim 3
Dependent Claim
106 words
Apparatus according to claim 1 in which said means for activating said indicator includes a third silicon controlled rectifier having a cathode connected to said source of direct current, a relay having a coil connected between an anode of said third silicon controlled rectifier and said source of direct current, said relay having normally open contacts connected to activate said indicator, and a gating circuit connected to the gate of said first silicon controlled rectifier and the gate of said third silicon controlled rectifier whereby when said first silicon controlled rectifier is on, one of said first pulses will turn said third silicon controlled rectifier on.
Claim 4
Dependent Claim
34 words
Apparatus according to claim 2 in which said indicator includes a shaft speed controller and an alarm and which includes a reset switch connected between said relay coil and said source of direct current.
Claim 5
Dependent Claim
35 words
Apparatus according to claim 1 in which said constant current source includes means to adjust the magnitude of said constant current and in which said second circuit means includes means for adjusting said predetermined magnitude.
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) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |