Patent US3857067A successfully refreshed from Google Patents.
US3857067A
Expired / Lapsed
US
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Switch failure monitoring device
Assignee: DEPARTMENT OF HEALTH EDUCATION
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Filing: 1972-12-13
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Granted: 1974-12-24
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Expires: 1992-12-13
Abstract
Abstract A switch failure monitoring device comprising two switches which are ganged together so that they operate substantially simultaneously; should either of them function incorrectly then a relay removes potential from the load.
Inventors
- 👤 M Zanboorie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:46
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/18; F16P3/20; H; H01; H01H; H01H47/00; H01H47/002
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
130 words
An electrical circuit for deenergizing a load device in case of improper functioning in microwave ovens and cabinet radiographic units comprising: an operating circuit; a monitoring circuit connected to the operating circuit; first means in the operating circuit for removing potential therefrom; first switch means in the operating circuit for applying potential to a load device, said first means being a power relay connected in series with said first switch; second switch means in the monitoring circuit; and time delay means in the monitoring circuit connected between the second switch and the power relay and arranged to energize the first means should either the first or second switches fail to function or should one of said switches be activated prematurely irrespective of whether a continuity through the load is maintained.
Claim 2
Dependent Claim
130 words
An electrical circuit for deenergizing a load device in case of improper functioning in microwave ovens and cabinet radiographic units comprising: an operating circuit; a monitoring circuit connected to the operating circuit; first means in the operating circuit for removing potential therefrom; first switch means in the operating circuit for applying potential to a load device, said first means being a power relay connected in series with said first switch; second switch means in the monitoring circuit; and time delay means in the monitoring circuit connected between the second switch and the power relay and arranged to energize the first means should either the first or second switches fail to function or should one of said switches be activated prematurely irrespective of whether a continuity through the load is maintained.
Claim 3
Dependent Claim
21 words
The device of claim 1 wherein the first and second switches are actuated by a common barrier for substantially simultaneous operation.
Claim 4
Dependent Claim
26 words
The device of claim 2 wherein the time delay means is a relay which operates after it has been energized for a predetermined length of time.
Claim 5
Dependent Claim
32 words
The device of claim 3 wherein the power relay has a plurality of contacts, one set of which removes potential from the operating circuit, and another set maintains potential on the relay.
Claim 6
Dependent Claim
97 words
A safety circuit comprising: a power relay connected to a source of potential; a monitoring switch connected to the power relay for applying potential to a load; a monitor switch connected by a common barrier to the monitored switch so that the switches operate substantially simultaneously; and a time delay relay connected between the monitoring switch and the power relay whereby should either switch fail to function normally or be prematurely activated the time delay relay will energize the power relay to remove potential from the load irrespective of whether a continuity through the load is maintained.
Claim 7
Dependent Claim
97 words
A safety circuit comprising: a power relay connected to a source of potential; a monitoring switch connected to the power relay for applying potential to a load; a monitor switch connected by a common barrier to the monitored switch so that the switches operate substantially simultaneously; and a time delay relay connected between the monitoring switch and the power relay whereby should either switch fail to function normally or be prematurely activated the time delay relay will energize the power relay to remove potential from the load irrespective of whether a continuity through the load is maintained.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |