US4278970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alarm circuit for detecting overheated condition
Assignee: Individual
•
Filing: 1979-05-02
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Granted: 1981-07-14
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Expires: 1999-05-02
Abstract
Abstract An alarm circuit for detection of an overheated condition comprises a bridge rectifier or a battery to provide a d.c. input, and a detector bridge including a thermistor and Zener diode in adjacent arms. The diode is set to operate along that portion of the thermistor response curve which is slowly changing. Hence, the Zener diode will be activated if the thermistor detects at the very onset of an overheated condition. Bridge unbalance is fed to an operational amplifier which activates a transistor to turn on an alarm such as an audio indicator, LED, telemetry system, etc. The alarm circuit has application for detection of a line overload, as a monitoring device for patients and for persons undergoing physical activity such as joggers and the like. By sounding an early alarm, overheating in a line wire caused by say, an overheated appliance, can be corrected with a consequent energy saving and minimizing damage to the appliance.
Inventors
- 👤 Michael Streczyn
- 👤 Joseph B. Loughlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:15
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/01; G; G01; G01K; G01K3/00; G01K3/005; G01R; G01R17/00; G01R17/10; G01R17/105; G01R19/00; G01R19/165; G01R19/16566; G01R19/16576; G08; G08B; G08B17/00; G08B17/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
121 words
A detecting circuit for an overheated condition, comprising: (a.) a d.c. powered bridge circuit having a detector thermistor in a bridge arm, the bridge being fed by the d.c. source; (b.) thermistor response detector in an adjacent bridge arm, the detector being set for a response to thermistor changes in about the 300° K.-400° K. range; (c.) a two state comparator amplifier for activation by the thermistor response detector: (d.) an on-off switch activated by the amplifier; and, (e.) output signal means for the circuit connected to the on-off switch, whereby a bridge unbalance due to thermistor changes caused by an overload will activate the thermistor response detector, thereby activating the on-off switch and then turn on the output signal means.
Claim 2
Dependent Claim
121 words
A detecting circuit for an overheated condition, comprising: (a.) a d.c. powered bridge circuit having a detector thermistor in a bridge arm, the bridge being fed by the d.c. source; (b.) thermistor response detector in an adjacent bridge arm, the detector being set for a response to thermistor changes in about the 300° K.-400° K. range; (c.) a two state comparator amplifier for activation by the thermistor response detector: (d.) an on-off switch activated by the amplifier; and, (e.) output signal means for the circuit connected to the on-off switch, whereby a bridge unbalance due to thermistor changes caused by an overload will activate the thermistor response detector, thereby activating the on-off switch and then turn on the output signal means.
Claim 3
Dependent Claim
21 words
The detecting circuit of claim 1 in which the comparator is an operational amplifier and the on-off switch is a transistor.
Claim 4
Dependent Claim
13 words
The circuit of claim 1, adapted for detection of an overheated body condition.
Claim 5
Dependent Claim
13 words
The circuit of claim 1 adapted for detection of an overheated line wire.
Claim 6
Dependent Claim
14 words
The circuit of claim 1, in which the thermistor response detector is a thermistor.
Claim 7
Dependent Claim
13 words
The circuit of claim 1, in which the detector is a Zener diode.
Claim 8
Dependent Claim
13 words
The apparatus of claim 1, comprising a plug board mounting for the circuit.
Claim 9
Independent Claim
100 words
A method for signalling an overheated body condition, comprising: (a.) detecting skin temperature with a thermistor in one arm of a d.c. powered bridge circuit; (b.) providing a thermistor response detector in an adjacent opposing arm of the bridge circuit, the detector being set for a response to thermistor changes in the 300° K.-400° K. range; (c.) feeding bridge unbalance signals from the detector to a two state comparator amplifier; (d.) activating an on-off switch fed by the comparator when the bridge is unbalanced; and, (e.) turning on an output signal from the on-off switch, when the switch is activated.
Claim 10
Independent Claim
100 words
A method for signalling an overheated body condition, comprising: (a.) detecting skin temperature with a thermistor in one arm of a d.c. powered bridge circuit; (b.) providing a thermistor response detector in an adjacent opposing arm of the bridge circuit, the detector being set for a response to thermistor changes in the 300° K.-400° K. range; (c.) feeding bridge unbalance signals from the detector to a two state comparator amplifier; (d.) activating an on-off switch fed by the comparator when the bridge is unbalanced; and, (e.) turning on an output signal from the on-off switch, when the switch is activated.
Claim 11
Dependent Claim
20 words
The method of claim 6 in which the comparator is an operational amplifier and the on-off switch is a transitor.
Claim 12
Dependent Claim
12 words
The method of claim 8 in which a thermistor is the detector.
Claim 13
Dependent Claim
13 words
The method of claim 8, in which the detector is a Zener diode.
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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) | 1984-07-13 | 1985-01-12 | 1985-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-13 | 1989-01-12 | 1989-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-13 | 1993-01-12 | 1993-07-14 | $7700.00 | Window Closed / Lapsed |