US3340867A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impedance plethysmograph
Assignee: University of Minnesota Twin Cities
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Filing: 1964-08-19
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Granted: 1967-09-12
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Expires: 1984-08-19
Abstract
No abstract record available.
Inventors
- 👤 William G Kubicek
- 👤 Kinnen Edwin
- 👤 Robert P Patterson
- 👤 David A Witsoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:38
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/026; A61B5/0295
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
157 words
A PLETHYSMOGRAPH FOR MEASURING CARDIAC OUTPUT COMPRISING IN COMBINATION EXCITATION ELECTRODE MEANS ADAPTED TO BE CONNECTED TO A MAMMALIAN SUBJECT AT THE SUPERIOR AND INFERIOR ENDS OF THE THORAX, A CURRENT GENERATOR MEANS COMPRISING AN ELECTRONIC OSCILLATOR CONDUCTIVELY CONNECTED TO THE ELECTRODE MEANS FOR SUPPLYING A FLUCTUATING EXCITATION CURRENT THERETO, SENSOR MEANS ADAPTED TO BE CONDUCTIVELY CONNECTED TO SAID THORAX FOR CARRYING A SENSED ELECTRICAL SIGNAL WHICH VARIES AS THE IMPEDANCE CHANGES IN THE THORAX BETWEEN SAID ELECTRODE MEANS, A CONTROL MEANS CONDUCTIVELY CONNECTED TO THE OSCILLATOR FOR BALANCING THE CURRENT FROM THE OSCILLATOR WITH THE SENSED SIGNAL, A FIRST AMPLIFIED CONDUCTIVELY CONNECTED TO THE CONTROL MEANS, A SECOND AMPLIFIER CONNECTED TO SAID SENSOR MEANS WHEREBY SIGNALS OF APPROXIMATELY EQUAL STRENGTH ARE FED TO SAID FIRST AND SECOND AMPLIFIERS FROM SAID CONTROL AND SAID SENSOR MEANS RESPECTIVELY AND A VOLTAGE SUBSTRACTING MEANS CONDUCTIVELY CONNECTED TO EACH OF THE AMPLIFIERS FOR COMPARING THE OUTPUT OF EACH SAID AMPLIFIER.
Claim 2
Dependent Claim
157 words
A PLETHYSMOGRAPH FOR MEASURING CARDIAC OUTPUT COMPRISING IN COMBINATION EXCITATION ELECTRODE MEANS ADAPTED TO BE CONNECTED TO A MAMMALIAN SUBJECT AT THE SUPERIOR AND INFERIOR ENDS OF THE THORAX, A CURRENT GENERATOR MEANS COMPRISING AN ELECTRONIC OSCILLATOR CONDUCTIVELY CONNECTED TO THE ELECTRODE MEANS FOR SUPPLYING A FLUCTUATING EXCITATION CURRENT THERETO, SENSOR MEANS ADAPTED TO BE CONDUCTIVELY CONNECTED TO SAID THORAX FOR CARRYING A SENSED ELECTRICAL SIGNAL WHICH VARIES AS THE IMPEDANCE CHANGES IN THE THORAX BETWEEN SAID ELECTRODE MEANS, A CONTROL MEANS CONDUCTIVELY CONNECTED TO THE OSCILLATOR FOR BALANCING THE CURRENT FROM THE OSCILLATOR WITH THE SENSED SIGNAL, A FIRST AMPLIFIED CONDUCTIVELY CONNECTED TO THE CONTROL MEANS, A SECOND AMPLIFIER CONNECTED TO SAID SENSOR MEANS WHEREBY SIGNALS OF APPROXIMATELY EQUAL STRENGTH ARE FED TO SAID FIRST AND SECOND AMPLIFIERS FROM SAID CONTROL AND SAID SENSOR MEANS RESPECTIVELY AND A VOLTAGE SUBSTRACTING MEANS CONDUCTIVELY CONNECTED TO EACH OF THE AMPLIFIERS FOR COMPARING THE OUTPUT OF EACH SAID AMPLIFIER.
References Cited (Backward Citations)
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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) | 1970-09-11 | 1971-03-13 | 1971-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-09-11 | 1975-03-13 | 1975-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-09-11 | 1979-03-13 | 1979-09-12 | $7700.00 | Window Closed / Lapsed |