US3552385A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for measuring blood pressure
Assignee: US Philips Corp
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Filing: 1968-04-05
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Granted: 1971-01-05
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Expires: 1988-04-05
Abstract
Abstract A device for measuring blood pressure comprising two outer electrodes and a central electrode pressed against an artery by an inflatable pressure cuff. High frequency energy is supplied to the outer electrodes. Voltage pulses are produced between each outer electrode and the central electrode and are compared in a difference amplifier to produce an output voltage determined by the phase shift therebetween. A threshold discriminator having a variable threshold voltage determined by the peak value of the input voltage is coupled to the output of said difference amplifier and operates a pressure valve relay when the amplifier output voltage falls below the threshold voltage.
Inventors
- 👤 Frits Jacques Janssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:18
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/021; A61B5/022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
184 words
A device for measuring blood pressure comprising, an inflatable cuff adapted to be pressed against a body surface over an artery, means for indicating the pressure in said cuff, first and second electrodes adapted to be spaced apart on the part of the body covered by said cuff, a third electrode adapted to be placed on said body part between the first and second electrodes, means for supplying a high-frequency electric current to said first and second electrodes, a difference amplifier, means connecting said first and third electrodes and said second and third electrodes to the input of said difference amplifier to form first and second current circuits, respectively, voltages being generated in said current circuits to produce a measuring voltage in the difference amplifier that is mainly dependent upon the mutual phase shift between said voltages means for coupling sad measuring voltage to a threshold discriminator having a variable threshold voltage that is dependent on the peak value of the voltage supplied thereto and means controlled by said discriminator for actuating said pressure-indicating means when the measuring voltage falls below the threshold voltage.
Claim 2
Independent Claim
184 words
A device for measuring blood pressure comprising, an inflatable cuff adapted to be pressed against a body surface over an artery, means for indicating the pressure in said cuff, first and second electrodes adapted to be spaced apart on the part of the body covered by said cuff, a third electrode adapted to be placed on said body part between the first and second electrodes, means for supplying a high-frequency electric current to said first and second electrodes, a difference amplifier, means connecting said first and third electrodes and said second and third electrodes to the input of said difference amplifier to form first and second current circuits, respectively, voltages being generated in said current circuits to produce a measuring voltage in the difference amplifier that is mainly dependent upon the mutual phase shift between said voltages means for coupling sad measuring voltage to a threshold discriminator having a variable threshold voltage that is dependent on the peak value of the voltage supplied thereto and means controlled by said discriminator for actuating said pressure-indicating means when the measuring voltage falls below the threshold voltage.
Claim 3
Dependent Claim
56 words
A device as claimed in claim 1, characterized in that the central electrode is provided wherein the third electrode is centrally disposed between the first and second electrodes under the cuff alongside the center of the cuff, at least beyond the position of the largest depression, on the side remote from the inlet of the bloodstream.
Claim 4
Dependent Claim
115 words
A device as claimed in claim 1 herein said electrodes are adapted to be in substantial alignment with the artery so that said second electrode forms the distal electrode, said pressure indicating means including first and second pressure gauges adapted to indicate the diastolic pressure and the systolic pressure, respectively, means for inflating said cuff to a pressure which will occlude the artery and thereafter gradually reducing the cuff pressure, and means coupled to the output of the distal electrode for operating said second pressure gauge upon receipt of the first voltage pulse to occur in the distal electrode after occlusion of the artery, said actuating means being arranged to operate said first pressure gauge.
Claim 5
Dependent Claim
59 words
A device as claimed in claim 3 wherein said operating means comprises a gate circuit coupled to said distal electrode and a relay coupled to the output of the gate circuit, and said actuating means comprises a bistable trigger device coupled to the output of the discriminator and a second relay coupled to the output of said bistable device.
Claim 6
Dependent Claim
43 words
A device as claimed in claim 1 wherein said high-frequency current supply means comprises an oscillator operating at approximately 100kHz., said device further comprising first and second diodes connected between said first and second electrodes, respectively, and the input of said difference amplifier.
Claim 7
Independent Claim
166 words
A device for measuring blood pressure comprising, first, second and third electrodes adapted to be spaced apart on a body surface in alignment with an artery, an inflatable pressure cuff adapted to enclose said electrodes and press against the surface over the artery, pressure-indicating means connected to said cuff, means for inflating the cuff above the artery occlusion pressure and thereafter gradually reducing the cuff pressure, a source of high-frequency electric energy coupled across said first and second electrodes, means coupled to said electrodes for comparing the voltage pulses generated between said first and third electrodes with the voltage pulses generated between said second and third electrodes to produce a control voltage that is determined by the phase difference between said voltage pulses, means for actuating said pressure-indicating means, and a threshold device coupled between the output of said comparing means and the input of said actuating means for triggering said actuating means when the phase difference between said voltage pulses decreases below a given value.
Claim 8
Independent Claim
166 words
A device for measuring blood pressure comprising, first, second and third electrodes adapted to be spaced apart on a body surface in alignment with an artery, an inflatable pressure cuff adapted to enclose said electrodes and press against the surface over the artery, pressure-indicating means connected to said cuff, means for inflating the cuff above the artery occlusion pressure and thereafter gradually reducing the cuff pressure, a source of high-frequency electric energy coupled across said first and second electrodes, means coupled to said electrodes for comparing the voltage pulses generated between said first and third electrodes with the voltage pulses generated between said second and third electrodes to produce a control voltage that is determined by the phase difference between said voltage pulses, means for actuating said pressure-indicating means, and a threshold device coupled between the output of said comparing means and the input of said actuating means for triggering said actuating means when the phase difference between said voltage pulses decreases below a given value.
Claim 9
Dependent Claim
37 words
A device as claimed in claim 6 wherein said threshold device comprises a discriminator having a threshold voltage that can be set to a given diagram percentage of the maximum amplitude of the input voltage supplied thereto.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |