US3776040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical thermometer system and sensor therefor
Assignee: Individual
•
Filing: 1971-09-30
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Granted: 1973-12-04
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Expires: 1991-09-30
Abstract
Abstract An electrical clinical thermometer system including a probe for insertion into a body cavity. A temperature sensor is carried by the probe whose electrical resistance changes with temperature. This probe is connected into a wheatstone bridge circuit which is restored to a balanced condition by an adjustable resistor which is mechanically connected to a readout device that indicates the temperature at the sensor when a meter in the bridge circuit is at its reference setting. The system is insensitive to voltage changes such as from a battery whose voltage declines. The readout device holds its reading when the probe is removed from the cavity, and may be either mechanical or digital. A sensor for this system comprises an elongated metal body with a discontinuity which is bridged by a plurality of fuse-like resistances of different values which can selectively be destroyed so as finely to adjust the resistance of the sensor. Calibration means for the adjustable resistor enable the use of inexpensive, relatively low-tolerance components to secure a very accurate measurement.
Inventors
- 👤 E Gould
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:15
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/18; G01K7/183; G01K13/00; G01K13/20; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49085
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
278 words
An electrical clinical thermometer system comprising: a probe for insertion into a body cavity; a temperature sensor carried by the probe and having an electrical resistance which changes as a function of temperature, said sensor comprising an elongated metal layer, there being a discontinuity in the said layer which is initially bridged by a plurality of fuse-like resistances of different resistance values, whereby an adjustment of the resistance value of the sensor can be made by destroying the continuity of selected ones of said fuse-like resistances, there remaining in place and bridging the discontinuity at least one of said fuse-like resistances; a wheatstone bridge circuit having four arms joined in a hollow square at four terminals; a first and a second resistor connected in a first and a second one of said arms, connected to each other at the first of said terminals, said first and second resistors being of equal value; an adjustable resistor in a third of said arms connected at the second of said terminals with said second resistor, and also connected to the third of said terminals; connector means connected to said adjustable resistor at said third terminal and to the first of said resistors at the fourth of said terminals, said connector means being adapted to connect said sensor into the fourth arm; a voltage source connected to the first and third terminals; a meter connected to said second and fourth terminals; and readout means calibrated in degrees of temperature whose reading is determined by the value of the resistance required in the third arm in order to balance that of the sensor, and thereby to set the meter to a balanced setting.
Claim 2
Dependent Claim
278 words
An electrical clinical thermometer system comprising: a probe for insertion into a body cavity; a temperature sensor carried by the probe and having an electrical resistance which changes as a function of temperature, said sensor comprising an elongated metal layer, there being a discontinuity in the said layer which is initially bridged by a plurality of fuse-like resistances of different resistance values, whereby an adjustment of the resistance value of the sensor can be made by destroying the continuity of selected ones of said fuse-like resistances, there remaining in place and bridging the discontinuity at least one of said fuse-like resistances; a wheatstone bridge circuit having four arms joined in a hollow square at four terminals; a first and a second resistor connected in a first and a second one of said arms, connected to each other at the first of said terminals, said first and second resistors being of equal value; an adjustable resistor in a third of said arms connected at the second of said terminals with said second resistor, and also connected to the third of said terminals; connector means connected to said adjustable resistor at said third terminal and to the first of said resistors at the fourth of said terminals, said connector means being adapted to connect said sensor into the fourth arm; a voltage source connected to the first and third terminals; a meter connected to said second and fourth terminals; and readout means calibrated in degrees of temperature whose reading is determined by the value of the resistance required in the third arm in order to balance that of the sensor, and thereby to set the meter to a balanced setting.
Claim 3
Dependent Claim
18 words
A thermometer system according to claim 1 in which the sensor comprises an elongated and exposed metal layer.
Claim 4
Dependent Claim
16 words
A thermometer system according to claim 2 in which the metal of the layer is gold.
Claim 5
Dependent Claim
25 words
A thermometer system according to claim 1 in which a switch is connected between the voltage source and one of the first and third terminals.
Claim 6
Dependent Claim
44 words
A thermometer system according to claim 1 in which the third of said arms further includes a first and a second calibration resistor for setting the resistances in said third arm respective to sensor resistances respective to maximum and mimimum temperatures to be measured.
Claim 7
Dependent Claim
54 words
A thermometer system according to claim 5 in which the first calibration resistor is serially connected to the adjustable resistor and to the second terminal, the second calibration resistor is connected to the first calibration resistor and to the adjustable resistor at their mutual connection, and to an adjustable portion of said adjustable resistor.
Claim 8
Dependent Claim
34 words
A thermometer system according to claim 1 in which the resistance of the adjustable resistor is set by manual means, and in which the readout means comprises visual calibration carried by said manual means.
Claim 9
Dependent Claim
27 words
A thermometer system according to claim 7 in which the said manual means is a rotatable member mounted to a rotatable shaft which sets the adjustable resistor.
Claim 10
Dependent Claim
19 words
A system according to claim 1 in which said means calibrated in degrees of temperature is a digital readout.
Claim 11
Dependent Claim
21 words
A thermometer system accorDing to claim 1 in which a lamp is connected in circuitry between the first and third terminals.
Claim 12
Dependent Claim
92 words
A sensor for an electrical thermometer comprising: a base, and an elongated layer of metal on and adherent to said base, said metal having the property of changing resistance with temperature, there being a discontinuity in the said layer which is initially bridged by a plurality of fuse-like resistances of different resistance values, whereby an adjustment of the resistance value of the sensor can be made by destroying the continuity of selected ones of said fuse-like resistances, there remaining in place and bridging the discontinuity at least one of said fuse-like resistances.
Claim 13
Dependent Claim
92 words
A sensor for an electrical thermometer comprising: a base, and an elongated layer of metal on and adherent to said base, said metal having the property of changing resistance with temperature, there being a discontinuity in the said layer which is initially bridged by a plurality of fuse-like resistances of different resistance values, whereby an adjustment of the resistance value of the sensor can be made by destroying the continuity of selected ones of said fuse-like resistances, there remaining in place and bridging the discontinuity at least one of said fuse-like resistances.
Claim 14
Dependent Claim
15 words
A sensor according to claim 11 in which the metal of the layer is gold.
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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) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |