Patent US3746938A successfully refreshed from Google Patents.
US3746938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Interlock circuit
Assignee: White Consolidated Industries Inc
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Filing: 1972-08-31
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Granted: 1973-07-17
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Expires: 1992-08-31
Abstract
Abstract An interlock circuit providing electric power to a transformer or other electric device in response to one or more sensed conditions interrupts such power upon the cessation of one of the sensed conditions. The circuit includes at least one interlock switch, a current limiting fuse, a ballast resistor for drawing current through the fuse upon the cessation of one of the conditions to open the circuit, and a relay monitoring operability of the ballast resistor when energized to close an associated switch connecting the circuit for operation.
Inventors
- 👤 J Lamb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:33
CPC Classifications
H; H02; H02H; H02H5/00; H02H11/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
133 words
A circuit for supplying energy to an electric apparatus comprising main switch means for coupling the circuit to a source of electric energy, means for opening the circuit in response to excessive electric energy in same, means for coupling energy in the circuit to the electric apparatus, means for drawing excessive electric energy through said main switch means and said means for opening when a failure occurs in the former to effect opening of the latter, secondary switch means for electrically connecting said main switch means and said means for opening to said means for coupling, and means resPonsive to operability of said means for drawing for operating said secondary switch means, whereby upon sensing inoperability of said means for drawing said means for operating is disabled from operating said secondary switch means.
Claim 2
Dependent Claim
133 words
A circuit for supplying energy to an electric apparatus comprising main switch means for coupling the circuit to a source of electric energy, means for opening the circuit in response to excessive electric energy in same, means for coupling energy in the circuit to the electric apparatus, means for drawing excessive electric energy through said main switch means and said means for opening when a failure occurs in the former to effect opening of the latter, secondary switch means for electrically connecting said main switch means and said means for opening to said means for coupling, and means resPonsive to operability of said means for drawing for operating said secondary switch means, whereby upon sensing inoperability of said means for drawing said means for operating is disabled from operating said secondary switch means.
Claim 3
Dependent Claim
16 words
A circuit as set forth in claim 1 wherein said means for opening comprises fuse means.
Claim 4
Dependent Claim
16 words
A circuit as set forth in claim 1 wherein said means for coupling comprises transformer means.
Claim 5
Dependent Claim
16 words
A circuit as set forth in claim 1 wherein said means for drawing comprises resistor means.
Claim 6
Dependent Claim
17 words
A circuit as set forth in claim 4 wherein said means for drawing comprises further switch means.
Claim 7
Dependent Claim
58 words
A circuit as set forth in claim 5 wherein said further switch means comprises a double throw switch having a first position to permit the drawing of current through said means for opening upon failure of said main switch means and a second position to permit energization of said means for operating when said resistor means is operable.
Claim 8
Dependent Claim
19 words
A circuit as set forth in claim 1 wherein said secondary switch means comprises a relay operated switch means.
Claim 9
Dependent Claim
16 words
A circuit as set forth in claim 7 wherein said means for operating comprises a relay.
Claim 10
Dependent Claim
16 words
A circuit as set forth in claim 1 wherein said means for operating comprises a relay.
Claim 11
Dependent Claim
40 words
A circuit as set forth in claim 1 wherein said main switch means, said means for opening and said secondary switch means are connected in series, and said means for drawing is connected in parallel with said means for coupling.
References Cited (Backward Citations)
US3382409A
Cited
US3407279A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |