US4231372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety monitoring circuit for electrosurgical unit
Assignee: Valleylab Inc
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Filing: 1974-11-04
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Granted: 1980-11-04
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Expires: 1994-11-04
Abstract
Abstract A safety monitoring circuit for use in an electrosurgical unit is disclosed. The circuit is useful to indicate a fault in the return path between an RF source and a patient electrode in contact with a patient to prevent electrical burns to the patient that can occur due to improper patient contact with the patient electrode or a break in the return path. The circuit includes a current sensor connected in series in the return path to the RF source, which sensor provides an output indicative of the sensed current that is coupled through a DC amplifier to a comparator, the comparator providing an output only if a predetermined threshold is exceeded. When a comparator output is provided, a timer is triggered to energize, for a predetermined period of time, an alarm to indicate a sensed fault and/or actuate disabling circuitry to terminate application of electrical energy to the active electrode utilized in electrosurgery for cutting or coagulation.
Inventors
- 👤 David W. Newton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:10
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/14; A61B18/16; H; H02; H02H; H02H3/00; H02H3/16; H02H3/162; A61B18/1206; A61B18/1233; G; G01; G01R; G01R31/00; G01R31/50; G01R31/54
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
105 words
A radio-frequency electrosurgical device which comprises a radio-frequency generator, a power lead and a return lead, means for coupling the power lead and the return lead to the radio-frequency generator, an active electrosurgical electrode, means for coupling the power lead to the active electrosurgical electrode to power the active electrode, a passive electrode, means for coupling the passive electrode to the return lead, alternate path return means for coupling the return lead to ground at a point between the passive electrode and the radio-frequency generator, and means in the alternate path return means for indicating a predetermined radio-frequency return in the alternate path return means.
Claim 2
Dependent Claim
105 words
A radio-frequency electrosurgical device which comprises a radio-frequency generator, a power lead and a return lead, means for coupling the power lead and the return lead to the radio-frequency generator, an active electrosurgical electrode, means for coupling the power lead to the active electrosurgical electrode to power the active electrode, a passive electrode, means for coupling the passive electrode to the return lead, alternate path return means for coupling the return lead to ground at a point between the passive electrode and the radio-frequency generator, and means in the alternate path return means for indicating a predetermined radio-frequency return in the alternate path return means.
Claim 3
Dependent Claim
21 words
A device as in claim 1 where said indicating means in the alternate path return means is sensitive to rms current.
Claim 4
Dependent Claim
59 words
A device as in claim 1 including frequency sensitive impedance means disposed in series with said indicating means in the alternate path return means having a first value of impedance at 60 Hz and a second value of impedance at a frequency substantially greater than 60 Hz where the second value is less than that of the first value.
Claim 5
Dependent Claim
25 words
A device as in claim 3 where said frequency substantially greater than 60 Hz is a radio frequency corresponding to that of the radio-frequency generator.
Claim 6
Dependent Claim
15 words
A device as in claim 3 where said frequency sensitive impedance means is a capacitor.
Claim 7
Dependent Claim
16 words
A device as in claim 5 where the value of said capacitor is about 2000 pf.
Claim 8
Dependent Claim
52 words
A device as in claim 1 including timing means responsive to said indicating means in the alternate return path means for preventing the application of the output of said radio-frequency generator to said active and passive electrodes for a predetermined period of time after the indicating means indicates said predetermined radio-frequency return.
Claim 9
Dependent Claim
23 words
A device as in claim 1 where said means for coupling the power and return leads to the radio-frequency generator comprises a transformer.
References Cited (Backward Citations)
FR1275415A
Cited
DE1139927B
Cited
FR1347865A
Cited
US3513353A
Cited
US3826263A
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US3683923A
Cited
US3697808A
Cited
US3784842A
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US3828768A
Cited
US3812858A
Cited
US3905373A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |