US3708652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature controls
Assignee: USM Corp
•
Filing: 1970-11-04
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Granted: 1973-01-02
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Expires: 1990-11-04
Abstract
Abstract A temperature control for an electrically heated device having an electric heating element themally contacting the device for heating the device. The heating element has a temperature variable electrical property and is connected in one arm of a bridge circuit. The bridge circuit is connected across a source of electric energy to power the heating element. The bridge cross-over current operates means for digitally controlling the electric power supplied to the bridge circuit. A pulsing circuit periodically resets the power supplied to the bridge circuit to a predetermined one of the digital magnitude.
Inventors
- 👤 Waller M Salway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:24
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/2401
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
130 words
A temperature control for an electrically heated device comprising: an electrically powered heating element having an electric property responsive to temperature thermally connected to the device for heating the device; a source of electric power connected across the heating element; means electrically connected to the heating element and the source and responsive to the temperature responsive electric property of the element for digitally setting the source of electric power connected across the heating element to an on or off condition; and means having a pulsing circuit connected to the means for digitally controlling the source of electric power for periodically causing the digital control means to reset the source to an on condition after the control means has responded to a temperature to set the source to an off condition.
Claim 2
Dependent Claim
130 words
A temperature control for an electrically heated device comprising: an electrically powered heating element having an electric property responsive to temperature thermally connected to the device for heating the device; a source of electric power connected across the heating element; means electrically connected to the heating element and the source and responsive to the temperature responsive electric property of the element for digitally setting the source of electric power connected across the heating element to an on or off condition; and means having a pulsing circuit connected to the means for digitally controlling the source of electric power for periodically causing the digital control means to reset the source to an on condition after the control means has responded to a temperature to set the source to an off condition.
Claim 3
Dependent Claim
26 words
A temperature control as in claim 1, wherein: the electric property responsive to temperature is electrical resistance; and the digital setting means is a controllable switch.
Claim 4
Dependent Claim
48 words
A temperature control as in claim 2 and additionally comprising means electrically connected to the switch and responsive to the temperature induced resistance for controlliNg the switch for maintaining the digital setting of the source in an on condition until a predetermined temperature and induced resistance is reached.
References Cited (Backward Citations)
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Cited
US2918558A
Cited
US3329887A
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US3215818A
Cited
US3426202A
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US3536923A
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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) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |