US3964487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Uncomplicated load-adapting electrosurgical cutting generator
Assignee: Birtcher Corp
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Filing: 1974-12-09
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Granted: 1976-06-22
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Expires: 1994-12-09
Abstract
Abstract A high frequency signal for cutting human tissue is generated by common-emitter configured oscillator circuit that is adapted to maintain the cutting signal relatively constant in spite of impedance variations in the load caused by variations in the conduction of the tissue being cut.
Inventors
- 👤 Donald W. Judson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:33
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/1206; A61B2018/00636; A61B2018/00642; A61B2018/0066; A61B2018/00696; A61B2018/00755; A61B2018/00773; A61B2018/00875
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
107 words
In an electrosurgical device having a power supply, a cutting signal generator driven by said power supply, and switching means for selecting the output signal of said generator for supply to a varying impedance cutting electrode load, the improvement therein being a cutting signal generator comprising: amplifier means having an input and output circuit for supplying an output current in its output circuit which varies inversely with the impedance variation of said load; and means coupling the output current variation of said amplifier means to the input circuit of said amplifier means for causing said amplifier means to controllably reinforce the current variation in its output circuit.
Claim 2
Dependent Claim
107 words
In an electrosurgical device having a power supply, a cutting signal generator driven by said power supply, and switching means for selecting the output signal of said generator for supply to a varying impedance cutting electrode load, the improvement therein being a cutting signal generator comprising: amplifier means having an input and output circuit for supplying an output current in its output circuit which varies inversely with the impedance variation of said load; and means coupling the output current variation of said amplifier means to the input circuit of said amplifier means for causing said amplifier means to controllably reinforce the current variation in its output circuit.
Claim 3
Dependent Claim
25 words
The cutting signal generator of claim 1 wherein said coupling means include means for providing positive feedback to the input circuit of said amplifier means.
Claim 4
Dependent Claim
15 words
The cutting signal generator of claim 1 wherein said amplifier means comprises a transistor amplifier.
Claim 5
Dependent Claim
17 words
The cutting signal generator of claim 3 wherein said transistor amplifier comprises an NPN configured amplifier circuit.
Claim 6
Dependent Claim
23 words
The cutting signal generator of claim 4 further comprising a biasing resistor connected between the output and input circuit of said NPN transistor.
Claim 7
Dependent Claim
31 words
The cutting signal generator of claim 1 further comprising transformer means for coupling said output circuit to the load and transferring the voltage generated in the output circuit to the load.
Claim 8
Dependent Claim
23 words
The cutting signal generator of claim 1 wherein said coupling means comprises a transformer inversely coupling said output circuit to said input circuit.
Claim 9
Dependent Claim
28 words
The cutting signal generator of claim 7 further comprising a capacitor connecting said output-input coupling transformer to said input circuit, providing a desired time-constant for the cutting signal.
Claim 10
Dependent Claim
186 words
In an electrosurgical device having a power supply, a cutting signal generator driven by said power supply, and switching means for selecting the output signal of said generator for supply to a varying impedance cutting electrode load, the improvement therein being a cutting signal generator that maintains a relatively constant voltage across said varying impedance cutting electrode load, said cutting signal generator comprising: amplifier means having an input circuit and an output circuit for amplifying the signal supplied to its input circuit; a first coupling transformer having a primary and a secondary winding, said secondary winding being directly connected to said load and said primary winding being connected in the output circuit of said amplifier means; and a second transformer having a primary and secondary winding, said primary winding of said second transformer being connected to the primary winding of said first transformer and said secondary winding of said second transformer being connected in the input circuit of said amplifier means in a manner to inversely couple a signal generated in the primary winding of said second transformer to the input circuit of said amplifier means.
Claim 11
Dependent Claim
186 words
In an electrosurgical device having a power supply, a cutting signal generator driven by said power supply, and switching means for selecting the output signal of said generator for supply to a varying impedance cutting electrode load, the improvement therein being a cutting signal generator that maintains a relatively constant voltage across said varying impedance cutting electrode load, said cutting signal generator comprising: amplifier means having an input circuit and an output circuit for amplifying the signal supplied to its input circuit; a first coupling transformer having a primary and a secondary winding, said secondary winding being directly connected to said load and said primary winding being connected in the output circuit of said amplifier means; and a second transformer having a primary and secondary winding, said primary winding of said second transformer being connected to the primary winding of said first transformer and said secondary winding of said second transformer being connected in the input circuit of said amplifier means in a manner to inversely couple a signal generated in the primary winding of said second transformer to the input circuit of said amplifier means.
Claim 12
Dependent Claim
27 words
The electrosurgical device of claim 9, further comprising a capacitor connected between the secondary winding of said second transformer and the input circuit of said amplifier means.
Claim 13
Dependent Claim
23 words
The electrosurgical device of claim 10 wherein the primary and secondary winding of said second transformer provide voltage inversion between the two windings.
Claim 14
Dependent Claim
14 words
The electrosurgical device of claim 10 wherein said amplifier means comprises a transistor amplifier.
Claim 15
Dependent Claim
16 words
The electrosurgical device of claim 12 wherein said transistor amplifier comprises an NPN configured amplifier circuit.
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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) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |