US3870047A - Electrosurgical device - Google Patents

Abstract

An electrosurgical device in which high frequency electrical energy powers a cutting electrode. Radio frequency energy is set up in a driver coil and a driven coil mounted in a handpiece. The driver coil energizes the driven coil to energize a surgical electrode connected to one end of the driven coil. Connection between the source of radio frequency energy and the driver coil includes a circuit in which condensers and impedances are so connected that, if there is a failure of the condensers, energy is dissipated. Sonic warning signals indicate production of cutting, coagulating, and blended currents.

Description

O United States Patent 1111 3,870,047

Gonser Mar. 11, 1975 [54] ELECTROSURGICAL DEVICE FOREIGN PATENTS OR APPLICATIONS Inventori Donald GMS", Forest Park Ohio 171,157 10/1951 Germany l28/303.l3

[73] Assignee: Dentsply Research and Development Corporation Milford, Del Primary Examzner-Rwhard A. Gaudet Assistant Exammer-Lee S. Cohen [22] Flled? 1973 Attorney, Agent, or Firm-James W. Pearce; Roy F. [21] AppL N02 414,646 Schaeperklaus; J. William Berkstresser [57] ABSTRACT [52] 'g f jig An electrosurgical device in which high frequency [51] l g 3 5 electrical energy powers a cutting electrode. Radio [58]Fleld 0f Searchm 128/30 3 4 j frequency energy is set up in a driver coil and a driven 12880318 303'1 l1 coil mounted in a handpiece. The driver coil energizes the driven coil to energize a surgical electrode con- [56] References C'ted nected to one end of the driven coil Connection be- UNITED STATES PATENTS tween the source of radio frequency energy and the l,805,904 5/1931 Carpenter l28/303.14 driver coil includes a circuit in which condensers and 2,238,834 /19 1 Travers v v 3 /1 E impedances are so connected that, if there is a failure 39391496 5/1963 DFgellfmnm 128/303-14 of the condensers, energy is dissipated. Sonic warning i signals indicate production of cutting, coagulating, v a 30 e a 3,804,096 4/1974 Gonser l28/303.l4 and blended Currents 3,807,404 4/1974 Weissman et al 128603.14 6 Claims, 10 Drawing Figures sum 1 B 3 /IQ la D PATENTED MAR] 1 5 SHEET 2 OF 3 3' v Vila!) 1 ELECTROSURGICAL DEVICE This invention relates to an electrosurgical device. More particularly, this invention relates to a multipurpose electrosurgical device. The device of this invention represents an improvement in the type of device shown in my copending application Ser. No. 310,830, filed Nov. 30, l972, now US. Pat. No. 3,804,096.

An object of this invention is to provide a radio frequency electrosurgical device in which a surgical electrode can be energized by a handpiece coil connected thereto, which handpiece coil, in turn, is energized by a driver coil coupled thereto, the radio frequency energy being supplied through a transmission line from a radio frequency power source.

A further object of this invention is to provide such a device which develops both a cutting current and a coagulating current and which provides a sonic warning signal of one frequency when the cutting current is being produced and a sonic warning signal of a different frequency when the coagulating current is being produced.

A further object of this invention is to provide such a device which also develops a blended current and which provides a sonic warning signal which is a blend of the frequencies when the blended current is being developed.

A further object of this invention is to provide such a device in which radio-frequency electrosurgical current is fed to an electrosurgical instrument through condensers in series between a power source and the instrument, and means is provided between condensers for bleeding on non-radio-frequency current to ground in the event of condenser failure.

Briefly, this invention provides an electrosurgical device including a handpiece in which a first coil and a second coil are wound on a handpiece core. A source of radio-frenquency current of an electrosurgical frequency is coupled to one end of the second coil and an electrode is connected to one end of the first coil. The source of radio-frequency current is coupled to the second coil through series connected condensers, and inductance means is provided between condensers to bleed off non-radio-frequency current to ground in the event of condenser failure. The power source has means for generating cutting current, coagulating current, and blended'current. Sonic warning devices ofdifferent frequencies sound when the cutting and coagulating currents are being generated. A blended sound is produced when a blended current is generated,

The above and other objects and features of the invention will be apparent to those skilled in the art to which this invention pertains from the following detailed description and the drawings in which:

FIG. I is a view in side elevation of an electrosurgical device constructed in accordance with an embodiment of this invention, the device being shown in association with a fragmentary portion of a patient on a fragmentary portion ofa table, the table being shown in section;

FIG. 2 is an enlarged fragmentary view in lengthwise section of the electrosurgical device shown in FIG. 1, Wiring being omitted for clarity;

FIG. 3 is a plan view of a handpiece portion of the electrosurgical device, a case thereof being broken away to reveal interior construction;

FIG. 4 is a view in side elevation of an inner assembly of the handpiece portion;

FIG. 5 is a view in lengthwise section of the handpiece portion shown in FIG. 3, wiring thereof being broken away to reveal structural details;

FIG. 6 is a view in end elevation of a cap of the device;

FIG. 7 is another end elevational view of the cap shown in FIG. 6;

FIG. 8 is a view in section taken on the line 8-8 in FIG. 6;

FIG. 9 is an exploded view of a power cable of the electrosurgical device and end fastener elements thereof; and 9 FIG. 10 is a schematic circuit diagram of the device.

In the following detailed description and the drawings, like reference characters indicate like parts.

In FIG. 1 is shown anelectrosurgical device 14 con structed in accordance with an embodiment of this invention. Thedevice 14 includes ahandpiece portion 16 and acable connecting portion 17. Thecable connecting portion 17 is mounted on an end of acoaxial cable 18. Thehandpiece portion 16 is arranged to support asurgical electrode 19. In FIG. 1 the surgical electrode is shown in position to perform a surgical operation on apatient 21. The patient is shown in position on apassive electrode 22 and supported by a table 23 which underlies thepassive electrode 22. Thepassive electrode 22 is provided with alead 422.

The handpiece portion 16 (FIG. 5) includes a central tubularelectromagnetic core 24. A first or drivencoil 26 is wound on thecore 24. A layer ofinsulation 27 overlies the first coil, and a second ordriver coil 28 is wound on the layer of insulation. Astud 29, which is mounted in acentral bore 31 of thecore 24, supports a hollow chuck fitting 32. Asecond stud 33 mounted in thecentral bore 31 supports a hollowreceptacle sleeve fitting 34. Ahollow sleeve 36 of dielectric material surrounds the receptacle sleeve fitting 34, thecoils 26 and 28, and the chuck fitting 32 withchuck jaws 37 of thefitting 32 extending outwardly thereof. Thesurgical electrode 19 can be received inside thechuck jaws 37. A cap 39 (FIGS. 3 and 6-8) is threaded on thechuck jaws 37 and can tighten the chuck jaws on theelectrode 19. Thecap 39 has acentral opening 40 through which theelectrode 19 projects. One end portion 41 (FIG. 3) of thefirst coil 26 is attached to the chuck fitting 32 as by soldering so that theend portion 41 of thefirst coil 26 is electrically connected to theelectrode 19.

Acable connector receptacle 42 is mounted in thereceptacle sleeve fitting 34. As shown in FIG. 2, thecable connector receptacle 42 includes acentral tube 43, which is supported by aninsulator sleeve 44. Theother end portion 46 of thefirst coil 26 is attached to thetube 43 as shown in FIG. 3. Oneend portion 47 of thesecond coil 28 is soldered to theend portion 46 of thecoil 26. Theother end portion 48 of thesecond coil 28 is attached to one side of acapacitor 49. The other side of thecapacitor 49 is attached to the receptacle sleeve fitting 34'by solder as indicated at 51.

Thecable connector receptacle 42 is provided with a central socket 52 (FIG. 5) which can receive a coaxialcable end assembly 53. The coaxialcable end assembly 53 includes a body 54 (FIGS. 2 and 9), anannular latch member 56, and an annularlatch actuator member 57. Thebody 54 supportsannular insulator members 58 and 59 (FIG. 2) inside which is mounted acontact member 61 having ahead 62 which can be received inside thecentral tube 43 in electrical connection therewith. A central lead 63 (FIG. 9) of thecoaxial cable 18 can be received inside a socket 64 (FIG. 2) in thecontact member 61 with an insulating layer 66 (FIG. 9).of thecoaxial cable 18 being received inside acentral bore 67 of thebody 54. An end portion of anannular conductor 68 of thecoaxial cable 18 overlies astem 69 of thebody 54 to form an electrical connection therewith. Asleeve 71, whichsurrounds thecable 18, can be advanced to the position shown in dotdash lines at 71A to hold theannular conductor 68 in position on thestem 69. Anouter insulation sleeve 73 forms an outer layer of. thecoaxial cable 18 surrounding theannular conductor 68.

Thelatch member 56 is threaded on thebody 54 and includes latch hooks 76 mounted onspring arms 77 which resiliently urge the latch hooks 76 outwardly. Thelatch actuator 57 is slideably mounted on thelatch member 56. The latch actuator 57' includesslots 78 through which thehooks 76 extend. A sleeve 79 (FIG. 2) of insulating material is mounted on thelatch actuator member 57. When theassembly 53 is mounted in v thecentral socket 52, theteeth 76 extend into an annular slot 81 (FIG. 2) in the wall of thesocket 52 to lock theassembly 53 in thesocket 52. When theinsulation sleeve 79 and thelatch actuator 57 are moved to the left as shown in FIG. 2, theteeth 76 are urged inwardly to cause release of theteeth 76 from theslot 81 to permit removal of thecable end assembly 53.

' In FIG. is shown schematically the wiring diagram of the device. Alternating current power is supplied by power leads 111 and 112. A power line radiofrequency interference filter 113 includingcondensers 114 and 115 andinductances 116 and 117 greatly attenuates radio frequency feed-back to the power leads. Apower line fuse 118 is provided in the lead 111. Aninterlock switch 119 can be provided in the power lead 111. Theinterlock switch 119 is closed during operation of the device but can be arranged to open when a casing of the device (not shown) is opened.

Leads 121 and 122 from thepower line filter 113 are connected topoles 123 and 124, respectively, of a triple pole double throw on-off switch 126. When theonoff switch 126 is in the position shown (off position), theleads 121ans 122 are connected to power a primary winding 127 of atransformer 128 to impress a low voltage such as 4 volts on a secondary winding 129 thereof. When the on-off switch 126 is in its other position (on position), theleads 121 and 122,are connected to a primary winding 1291 of atransformer 130 to power the transformer. Apanel light 131 is connected in parallel with the primary winding 1291 to indicate that the primary winding 1291 is powered. A thermally activatedcircuit breaker 1292 in series with the primary winding 1291 protects thetransformer 130. Athird pole 132 of theswitch 126, when in the on position, connects leads 133 and 134 to connect one side of a heater electrode 135 of a tetrode mainpower amplitier tube 136 to one side of a first secondary winding 137 of thetransformer 130, which can be constructed to produce approximately 6 volts AC to the heater electrode 135. Acapacitor 2135 is connected between theline 133 and ground to shunt any radio-frequency current from the heater electrode 135. The other side of the first secondary winding 137 is connected to ground as is the opposite side of the heater electrode 135. Afan motor 1371 is also connected in parallel with the primary winding 1291 to drive afan 1372 which blows air on thetetrode 136 and other components to cool the tetrode and other components. When the on-off switch 126 is swung to its off position, thepole 132 connects thelead 133 to the secondary winding 129 of thetransformer 128 so that the heater electrode 135 is heated not only when the on-off switch 126 is in the on position but also when the on-off switch 126 is in the off position. As already pointed out, the secon dary winding 129 of thetransformer 128 can be arranged to deliver about four voltsso that the heater electrode 135 is heated but at a lower temperature when theswitch 126 is in the off position but is maintained at a sufficient temperature that the device will operate at once when theswitch 126 is turned on.

A secondary winding 146 of thetransformer 130 supplies a voltage of approximately 2000 volts AC across leads 147 and 148 to a fullwave bridge rectifier 149 which supplies 2000 volts direct current across leads 150 and 151. Thelead 150 is connected to ground as is acathode 152 of thetetrode 136. Thelead 151 is connected through aplate choke 153 and a parasitic suppressor network 154 to aplate 156 of thetetrode 136 so that 2000 volts DC is impressed between thecathode 152 and theplate 156 of thetetrode 136. Afilter condenser 157 smooths out wave form ripple from therectifier 149. A tappedresistor 159 and a fixedresistor 159A are connected in series across theleads 150 and 151. A lead 158 connected to the tap of the tappedresistor 159 supplies a positive potential through aresistor 161 and a lead 162 to a screen grid of thetetrode 136. A voltage of approximately 380 volts can be taken off at the tap which is maintained on the screen grid. Anappropriate resistance 164 bleeds offscreen grid current to ground. A capacitor 166 connected between thescreen grid lead 162 and ground removes or shunts out radio frequency from the screen grid. 1

Asection 146A of the second secondary winding 146 of thetransformer 130 is connected in parallel with a capacitor 1468 to form a tuned circuit tuned to a line input frequency, which can be Hertz, to stabilize the secondary winding voltages to a variation of approximately i1 percent with a change in input voltage of ilO percent impressed on the primary winding 129. Thus, thetransformer 130 is a substantially constant voltage transformer stabilizing all the circuitry of the device.

A bias voltage for acontrol grid 168 of thetetrode 136 is supplied by a third secondary winding 169 of thetransformer 130. A first lead 171 from the winding 169 is connected to ground and asecond lead 172 from the winding 169 is connected to arectifier 173. Therectifier 173 supplies a negative potential through aresistance 1741 and aninductance 1742 to alead 174, which is connected to one end of a first series winding 176 of atransformer 1761. The other end of the winding 176 is connected through a second series winding 1762 of thetransformer 1761 to a lead 179 connected to thecontrol grid 168 of thetetrode 136. Acondenser 181 which is connected between ground and ajunction 1743 smooths out the wave form of the potential from therectifier 173. Aresistance 183 connected in parallel with thecondenser 181 serves to discharge thecondenser 181 when the device is turned off. The bias voltage can be approximately l volts.

Oscillator circuits 184 and 186 for the device are powered from a fourth secondary winding 187 of thetransformer 130.Leads 188, 189 and 190 from the winding 187 are connected through a single poledouble throw switch 191 to a fullwave bridge rectifier 192 which supplies a DC voltage across leads 193 and 194. When theswitch 191 is in the position shown, a voltage of approximately 16 volts is supplied across theleads 193 and 194. When theswitch 191 is in nits other position, a voltage of approximately volts is supplied across theleads 193 and 194. Acondenser 195 connected across leads 193 and 194 smooths ripple voltage. Aresistance 1961 connected across theleads 193 and 194 discharges thecondenser 195 when the device is turned off. Thelead 193 is connected to ground. Thelead 194 is connected to the pole of a single pole double throughswitch 196. When theswitch 196 is in the position shown, thelead 194 is connected through ashort lead 197 to the pole of a single poledouble throw switch 198. Theswitches 196 and 198 can be foot operated switches. Theswitches 196 and 198 are shown in their normal positions. When theswitch 196 is turned to its other position, thelead 194 is connected to alead 199. When theswitch 198 is turned to its other position, while theswitch 196 remains in the position shown, thelead 194 is connected to lead 200. If theswitches 196 and 198 are both turned to their other position, thelead 194 is connected to thelead 199, and it is impossible to connect both theleads 199 and 200 to thelead 194 at the same time. Thelead 199 is connected to one side of apotentiometer 201. The other side of thepotentiometer 201 is connected to ground through anadjustable resistor 202. In a similar manner, thelead 200 is connected to one side of apotentiometer 203. The other side of thepotentiometer 203 is connected to ground through anadjustable resistor 204. Thus, when theswitch 196 is advanced to its other position, a selected DC voltage is impressed across thepotentiometer 201 and when theswitch 198 is advanced to its other position while theswitch 196 remains in the position shown, a selected DC voltage is impressed across thepotentiometer 203.

A voltage between Zero and the selected voltage is impressed upon a lead 206 connected to the tap of thepotentiometer 203 when theswitch 198 is in its other position and theswitch 196 is in the position shown. Thelead 206 is connected through an inductance or choke 207 to the collector of atransistor 208, which is a part of theoscillator circuit 186. The emitter of thetransistor 208 is connected to ground. Thelead 206 is also connected throughresistors 209 and 211 and a rectifier 212 to one side of a tickler coil 213. The rectifier 212 functions to reverse bias the base ofthetransistor 208 and is connected to one side of the tickler coil 213, which is excited by a tank circuit consisting of an inductance 214 and acondenser 216 coupled to thetransistor 208 in which continuous oscillation is set up by the tank circuit. The other side of the tickler coil 213 is connected to the base of thetransistor 208. The rectifier 212 establishes the reverse bias required by the base of thetransistor 208 and is also connected to ground through a condenser 217 which establishes the bias network circuitry. Abias rectifier 2171 is connected between ground and ajunction between theresistors 209 and 211. The tank circuit is connected with the collector of thetransistor 208 through a coupling condenser 218. Acondenser 219 is connected between the emitter and the collector of thetransistor 208 to shunt out radio frequency potentials. Acapacitor 777 acts to provide a bypass to ground shunt for attenuating radio frequency feed-back into theline 206 when theoscillating circuit 186 is in operation. The tank circuit can be tuned to oscillate at a rate ofapproximately 1.8 megaHertz. The oscillation is picked up by the transformer winding 1762 and the voltage thereof is multiplied by the transformer winding and impressed by way of thelead 179 on thecontrol grid 168 of thetetrode 136 to provide an amplified output by thetetrode 136 of that frequency. The output of thetetrode 136 is impressed by way ofa lead 220 on an output circuit which is coupled throughcondenser 221 to a tuned pie network which includescondensers 222 and 225 andinductances 223 and 226. Right-hand ends of theinductances 223 and 226 are connected to ground so that, if there should be failure of thecondensers 221 and 222, the direct current output of thetetrode 136 would be drained off to ground without danger to the patient. A take-off lead 224 which is connected between thecondenser 222 and theinductance 223 extends to one side of a condenser 225. The other side of the condenser 225 is connected to thecentral lead 63 of thecoaxial cable 18 and through thecable end assembly 53 to one end of thesecond coil 28. Theannular conductor 68 of thecoaxial cable 18 is connected to ground. Thepassive electrode 22 is connected to one side of acondenser 227. The other side of thecondenser 227 is connected to ground. Thus, a continuous radio frequency oscillating potential is set up in thefirst coil 26 and in theelectrode 19.

When theswitch 198 is moved to its other position and theswitch 196 remains in the position shown and a single pole doublethrow blend switch 2341 is in the off position shown, a continuous oscillation is impressed on thecoil 28. When theswitch 196 is moved to its other position and while the single pole doublethrow blend switch 2341 is in the off position shown, theoscillating circuit 184 is energized to produce an interrupted oscillation in thedriver coil 28. Theoscillating circuit 184 is generally similar to thecircuit 186 already described and includes atransistor 237, atank circuit inductance 238, atank circuit capacitor 239, and atickler coil 240 and associated elements. Alead 241, which is connected to the tap of thepotentiometer 201, is connected through achoke 242 to the collector of thetransistor 237. Moving of theswitch 196 to its other position impresses a selected DC voltage across thepotentiometer 201 and a DC voltage between zero and the selected voltage is impressed upon thelead 241. The emitter of thetransistor 237 is connected to ground. Theoscillating circuit 184 is set in operation to deliver an oscillator frequency of approximately 1.8 megaHertz on the control grid of thetetrode 136. Thelead 199, which is connected to the high side of thepotentiometer 201, is also connected through the pole of theblend switch 2341 to alead 245, which is connected to base leads oftransistors 244 and 246, which form a multivibrator circuit. throughresistors 247 and 248, respectively. The collector lead of thetransistor 244 is coupled through acondenser 249 to the base of thetransistor 246 and the collector of thetransistor 246 is coupled through acondenser 251 to the base of thetransistor 244. The collectors of thetransistors 244 and 246 are connected to thelead 245 throughresistors 2511 and 2512, respectively. Emitters of thetransistors 244 and 246 are connected to ground. The multivibrator circuit can be arranged to oscillate at a rate of approximately 7,000 Hertz. A lead 252 from the collector of thetransistor 244 is connected through acoupling condenser 253 and arectifier 2531, and aresistor 2532 connected in parallel with therectifier 2531, to the base of thetransistor 237 so that the operation of theoscillating circuit 184 is interrupted at a rate of 7,000 Hertz to put an interrupted oscillating potential on the control grid of thetetrode 136 and to supply an interrupted radio-frequency oscillating potential at theelectrode 19. Therectifier 2531 and theresistor 2532 connected in parallel with therectifier 2531 forms a network which preserves the wave form generated by the multivibrator circuit as it is transmitted to theoscillator circuit 184.

Anadjustable capacitor 1765 is connected between the lead 179 and ground and can be adjusted so that it tunes with the transformer secondary coils 176 and 1762 and with thecapacitor 2172 so that the grid input is tuned with the plate series tuned circuit 222,223, 225, and 226. Both of these circuits are tuned with the driverinput oscillating circuits 184 and 186 at approxi mately 1.8 megaHertz.

When theblend switch 2341 is disposed in its other or on position, moving of theswitch 198 to its other position while theswitch 196 is in the position shown energizes both of theoscillating circuits 184 and 186.

Theoscillating circuit 186 is energized in the same manner as already described. Thelead 200, which is connected to theswitch 198, is connected through alead 256, arectifier 257, theblend switch 2341, thelead 245, and anadjustable resistor 2572 to thelead 199, which is connected to the right hand end of thepotentiometer 201. Therectifier 257 prevents unwanted cross feed between theleads 199 and 200. Both theoscillating circuit 184 and theoscillating circuit 186 are set in operation and an output is provided from v thetetrode 136 for energizing theelectrode 19 which combines the interrupted oscillation of thecircuit 184 with the uninterrupted oscillation of thecircuit 186.

Thelead 199, which is connected to the high side of thepotentiometer 201, is also connected to asonic signalling device 271, which is constructed to produce a sound signal of a selected frequency, which can be 2,900 Hz. Thesonic signalling device 271 is connected to ground through apole 2721 of an on-off switch 272 and aresistor 273. Similarly, thelead 200, which is connected to the high side of thepotentiometer 203, is also connected to a secondsonic signalling device 274, which is constructed to produce a sound signal ofa second selected frequency, which can be 4,500 Hz. Thesonic signalling device 274 is connected to ground through apole 2722 of the on-off switch 272 and aresistor 276. Thesonic signalling device 271 sounds when thepotentiometer 201 is energized to energize theoscillating circuit 184 to produce a sound signal which indicates to the user of the device that theoscillating circuit 184 is operating. Thesonic signalling device 274 similarly produces a sound signal when theoscillating circuit 186 is energized to indicate that theoscillating circuit 186 is operating. When both theoscillating circuits 184 and 186 are operating, i.e., when a blended current is being produced, a sound signal is produced which is a blend ofthe selected frequencies. if the user does not want sound signals, the on-off switch'272 can be opened. The size of theresistors 273 and 276 determines the loudness of the sound signals.

When the device-is to be used, anappropriate electrode 19 is mounted in the chuck jaws 37 (FIG. 5). The blend switch 2341 (FIG. 10) is disposed either in its other position at which a blend of interrupted and uniterrupted oscillations is produced, or in the of position shown at which only one of theoscillating circuits 184 and 186 can be used at one time. Theoutput range switch 191 is placed in either the position shown or in its other position. The cable end assembly 53 (FIG. 2) is mounted inside thecable connector receptacle 42. The main on-off switch 126 is turned on, and theelectrode 19 is moved to a position adjacent or touching tissues of the patient 21 (FIG. 1) at a point where electrosurgery is to be performed. The appropriate one of the foot operatedswitches 196 and 198 (FIG. 9) is moved to its other position to provide a radio frequency current flow in thecoil 28 which induces a like radio frequency oscillation in thecoil 26. As theelectrode 19 touches or approaches the body of the patient, an electro-surgical action is provided at theelectrode, and a return electrical path is provided through the ancillary orpassive electrode 22.

When the electrosurgical operation is to be an ordinary or usual cutting action, theblend switch 2341 is disposed in the position shown (off position), and the foot operatedswitch 198 is moved to its other position to set theoscillating circuit 186 in operation and to provide an uninterrupted oscillation. if a coagulating, dessicating, or fulgurating action is desired, the foot operatedswitch 196 is moved to its other position to cause operation of theoscillating circuit 184 and the multivibrator circuit of thetransistors 244 and 246 providing an interrupted oscillation. If a blend of interrupted and uninterrupted oscillations is required, as where very substantial tissue destruction is desired as in some cutting operations, theblend switch 2341 is moved to its other or on position, and theswitch 198 is moved to its other position to .cause delivery of a blending of interrupted and uninterrupted oscillations.

The power delivered by theoscillating circuit 184 can be adjusted by movement of the tap of thepotentiometer 201. The power delivered by theoscillating circuit 186 can be adjusted by movement of the tap of thepotentiometer 203.

The condenser 227 (FIG. 10), through which thepassive electrode 22 is coupled to ground, permits passage of radiofrequency current to permit electrosurgical action but limits passage oflower frequency current which might shock the patient. Thecondenser 49,

through which thedriver coil 28 is coupled to ground,

similarly permits passage of radiofrequency current but prevents passage of lower frequency current generated as a sub-harmonic of the radiofrequency current to isolate thecoils 28 and 26 from such lower frequency current. Thecondenser 49 is disposed in the handpiece to isolate thedriver coil 28 from theouter conductor 68 of thecoaxial cable 18 shield, which is at ground potential.

With the structure of this invention, a number of probe or handpiece elements canbe employed with a single power unit andcable 18, and change of handpiece elements can be rapidly and conveniently effected.

The electrosurgical device described above and illustrated in the drawings is subject to structural modification without departing from the spirit and scope of the appended claims.

Having described my invention, what I claim as new and desire to secure by letters patent is:

1. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, the power contact being connected to the cen tral lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, a condenser, and means for coupling the other end of the second coil to the outer conductor through the condenser.

2. A device as in claim 1 wherein the other end of the first coil is connected to the power contact.

3. A device as in claim 1 wherein a dielectric sleeve surrounds the coils and the socket means.

4. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the'core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, the power contact being connected to the central lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, and a condenser mounted in the hand piece, the other end of the second coil being coupled to ground through the condenser and the outer conductor of the coaxial cable, the other end of the first coil being connected to the power contact.

5. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, means connecting the power contact to the central lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, and a condenser, the socket means including a ground contact connected to the outer conductor of the coaxial cable, and the other end of the second coil being coupled to the ground contact through the condenser.

6. In an electrosurgical device, the combination of a coaxial cable having a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises a first coil, a second coil inductively coupled to the first coil, an electrode, means for connecting one end of the first coil to the electrode, means for connecting one end of the second coil to the central lead, and a condenser, the other end of the second coil being coupled to the outer conductor through the condenser, the second coil powering the first coil and the electrode, the outer conductor preventing radio-frequency leakage between the generating means and the handpiece.

Claims (6)

1. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, the power contact being connected to the central lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, a condenser, and means for coupling the other end of the second coil to the outer conductor through the condenser.

2. A device as in claim 1 wherein the other end of the first coil is connected to the power contact.

3. A device as in claim 1 wherein a dielectric sleeve surrounds the coils and the socket means.

4. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, the power contact being connected to the central lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, and a condenser mounted in the handpiece, the other end of the second coil being coupled to ground through the condenser and the outer conductor of the coaxial cable, the other end of the first coil being connected to the powEr contact.

5. In an electrosurgical device, the combination of a coaxial cable including a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises an elongated core, a first coil and a second coil wound on said core, means for supporting an electrosurgical electrode mounted at one end of the core, socket means mounted on the opposite end of the core, the socket means receiving an end connector portion of the coaxial cable, the socket means having a power contact, means connecting the power contact to the central lead of the coaxial cable, means for connecting one end of the first coil to the electrode holder, means for connecting one end of the second coil to the power contact, whereby an electrosurgical current is induced in the electrode, and a condenser, the socket means including a ground contact connected to the outer conductor of the coaxial cable, and the other end of the second coil being coupled to the ground contact through the condenser.

6. In an electrosurgical device, the combination of a coaxial cable having a central lead and an outer conductor and means for generating a radio-frequency current of an electrosurgical frequency in the central lead of the coaxial cable, with a handpiece which comprises a first coil, a second coil inductively coupled to the first coil, an electrode, means for connecting one end of the first coil to the electrode, means for connecting one end of the second coil to the central lead, and a condenser, the other end of the second coil being coupled to the outer conductor through the condenser, the second coil powering the first coil and the electrode, the outer conductor preventing radio-frequency leakage between the generating means and the handpiece.

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