Patent US3753003A successfully refreshed from Google Patents.
US3753003A
Expired / Lapsed
US
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Safety device against radiation leakage from microwave apparatus
Assignee: Industrie Zanussi SpA
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Filing: 1971-10-05
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Granted: 1973-08-14
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Expires: 1991-10-05
Abstract
Abstract A safety device for microwave ovens is disclosed, which prevents radiation leakage from such an oven, the device being of the kind where a gas lamp is located in the area where radiation leakages may occur, said lamp being connected serially with a potentiometer which cooperates with a controlled diode which drives a relay which cuts the feed to the microwave generating circuit, the safety device being characterized by further comprising a bistable circuit and an amplifier which are connected to one another in cascade arrangement, the bistable circuit and the amplifier being inserted between the potentiometer voltage tap and the control electrode of the controlled diode. By such an arrangement, the sensitivity, the promptness and the reliability of the safety device of the kind described are considerably improved.
Inventors
- 👤 L Mazza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:25
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/6414; H05B6/6417
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
149 words
A safety device for sensing and preventing radiation leakage from a microwave-producing apparatus having a microwave feeding circuit, said device comprising, in combination, a first circuit branch including a gas lamp which is sensitive to microwave radiation and which is disposed in a region of possible microwave radiation leakage from the microwave-producing apparatus, and a potentiometer electrically coupled with said gas lamp, said potentiometer having a voltage path providing a control voltage therefrom; a second circuit branch including a controllable diode having a control electrode, and a relay means serially connected to said controllable diode for energization thereby, said relay means upon energization opening the microwave feeding circuit; bistable circuit means receiving said control voltage from said potentiometer voltage tap for changing output states in response thereto; and amplifier means coupled between said bistable circuit means and said control electrode of said controllable diode for triggering said controllable diode.
Claim 2
Dependent Claim
149 words
A safety device for sensing and preventing radiation leakage from a microwave-producing apparatus having a microwave feeding circuit, said device comprising, in combination, a first circuit branch including a gas lamp which is sensitive to microwave radiation and which is disposed in a region of possible microwave radiation leakage from the microwave-producing apparatus, and a potentiometer electrically coupled with said gas lamp, said potentiometer having a voltage path providing a control voltage therefrom; a second circuit branch including a controllable diode having a control electrode, and a relay means serially connected to said controllable diode for energization thereby, said relay means upon energization opening the microwave feeding circuit; bistable circuit means receiving said control voltage from said potentiometer voltage tap for changing output states in response thereto; and amplifier means coupled between said bistable circuit means and said control electrode of said controllable diode for triggering said controllable diode.
Claim 3
Dependent Claim
51 words
A device according to claim 1, further including means effecting impedance matches between the output circuit of the control voltage and the input of the bistable circuit means, the output of said bistable circuit means and the input of said amplifier means and the amplifier output and said controlled diode input.
Claim 4
Dependent Claim
35 words
A device according to claim 1, characterized in that in parallel with the controlled diode there is arranged a normally open movable contact which is driven to become closed by the energization of said relay.
Claim 5
Dependent Claim
36 words
A device according to claim 1, characterized in that between the potentiometer voltage tap and the bistable circuit, there is inserted a capacitor for blocking the DC component of the control voltage taken from the potentiometer.
Claim 6
Dependent Claim
29 words
A device according to claim 1, characterized in that said bistable circuit means comprises a transistor the conductivity of which is dependent on the voltage drawn from the potentiometer.
Claim 7
Dependent Claim
47 words
A device according to claim 5, characterized in that said bistable circuit means further comprises a second transistor which is common-emitter connected with respect to tHe first transistor, the base of the second transistor being connected to the collector of the first transistor through a delay circuit.
Claim 8
Dependent Claim
50 words
A device according to claim 6, characterized in that said amplifier means comprises a transistor, whose base is connected to the collector of the first transistor of said bistable circuit means and the collector-emitter circuit comprises a load resistor across which the control voltage for the controlled diode is drawn.
References Cited (Backward Citations)
US3063010A
Cited
US3350702A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |