U.S. patent number 3,804,096 [Application Number 05/310,830] was granted by the patent office on 1974-04-16 for electrosurgical device.
This patent grant is currently assigned to Dentsply International Inc.. Invention is credited to Donald I. Gonser.
United States Patent |
3,804,096 |
Gonser |
April 16, 1974 |
ELECTROSURGICAL DEVICE
Abstract
An electrosurgical device in which high frequency electrical
energy powers a cutting electrode. Radio frequency energy is set up
in a driver coil which can be in a male member. A female handpiece
member can be removably mounted on the male member. A handpiece
coil in the handpiece member is energized by the driver coil to
energize a surgical electrode connected to one end of the handpiece
coil. A return path from a patient is formed by coupling between
the patient and the handpiece coil. The handpiece element can be
readily removed from the male member so that another handpiece
element can be substituted. A releasable electric connection is
formed when the male member is inserted in the handpiece element to
connect the end of the handpiece coil remote from the surgical
electrode to ground.
Inventors: |
Gonser; Donald I. (Forest Park,
OH) |
Assignee: |
Dentsply International Inc.
(York, PA)
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Family
ID: |
23204291 |
Appl.
No.: |
05/310,830 |
Filed: |
November 30, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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214044 |
Dec 30, 1971 |
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Current U.S.
Class: |
606/45;
128/DIG.22; 606/49; 606/37 |
Current CPC
Class: |
A61B
18/1206 (20130101); A61B 18/1402 (20130101); A61B
17/32 (20130101); A61B 18/12 (20130101); A61B
2018/0066 (20130101); C04B 2237/366 (20130101); Y10S
128/22 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61B 18/12 (20060101); A61B
18/14 (20060101); A61b 017/36 () |
Field of
Search: |
;128/DIG.22,303.10,303.14,421,422 ;321/2,4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Medbery; Aldrich F.
Attorney, Agent or Firm: Pearce; James W.
Parent Case Text
This is a continuation-in-part of my copending application Ser. No.
214,044 filed Dec. 30, 1971, now abandoned.
Claims
Having described my invention, what I claim as new and desire to
secure by letters patent is:
1. An electrosurgical device which comprises a driver element
including a driver coil, a transmission line having grounding means
and also including two line conductors which are connected to
opposite ends of the driver coil, means for impressing a radio
frequency oscillating electrical current on the conductors to
energize the driver coil, a handpiece element having a socket
thereinside, the driver element being removably and slidably
received inside the socket of the handpiece element, a handpiece
coil in the handpiece element surrounding the socket, means for
attaching a surgical electrode to one end of the handpiece coil
with a portion of the surgical electrode exposed, contact means on
the driver element connected to the grounding means, contact means
on the handpiece element at the socket connected to the other end
of the handpiece coil and engaging the contact means of the driver
element when the driver element is seated in the socket, the
energized driver coil located adjacent but spaced from the
handpiece coil inducing a radio frequency oscillating electrical
current in the handpiece coil, there being electrical coupling
between the handpiece coil and a patient when the surgical
electrode is brought into proximity with tissues of the
patient.
2. An electrosurgical device as in claim 1 wherein the grounding
means in the transmission line is a conducting sheath surrounding
the conductors and is connected to ground of the means for
impressing a radio frequency oscillating electrical potential.
3. An electrosurgical device as in claim 2 wherein there is a
dielectric cover surrounding the conducting sheath.
4. An electrosurgical device as in claim 1 wherein the contact
means on the driver element is a metal ring surrounding the driver
element and the contact means of the handpiece element is a metal
band attached to the handpiece coil and extending through an
opening in a wall of the handpiece element into the socket of the
handpiece element, resilience of the wall causing the wall to grip
the handpiece element contact means to hold the contact means in
firm engagement.
5. An electrosurgical device which comprises a driver element
including a driver coil, a transmission line including at least two
conductors, grounding means, a tubular dielectric member, a
dielectric head end member mounted in one end of the tubular
member, an electrically conducting rod mounted in the head end
member extending along the tubular member substantially axially
thereof, and a tubular magnetic core member mounted on the rod, the
driver coil being wound on the magnetic core member inside the
tubular member, one end of the driver coil being attached to the
electrically conducting rod, the transmission line extending
through an opening in the head end member into the interior of the
tubular member, one of the conductors of the transmission line
being connected to the opposite end of the driver coil, the other
of the conductors of the transmission line being attached to the
electrically conducting rod, means for impressing a radio frequency
oscillating electrical current on the conductors to energize the
driver coil, a handpiece element having a socket thereinside, the
driver element being removably and slidably received inside the
socket of the handpiece element, a handpiece coil in the handpiece
element surrounding the socket, means for attaching a surgical
electrode to one end of the handpiece coil with a portion of the
surgical electrode exposed, contact means on the driver element
connected to the grounding means, contact means on the handpiece
element at the socket connected to the other end of the handpiece
coil and engaging the contact means of the driver element when the
driver element is seated in the socket, the driver coil inducing a
radio frequency oscillating electrical current in the handpiece
coil, there being electrical coupling between the handpiece coil
and a patient when the surgical electrode is brought into proximity
with tissues of the patient.
6. An electrosurgical device as in claim 5 wherein the transmission
line includes a conducting shield surrounding the conductors
thereof and the contact means on the driver element is a ring
surrounding the tubular dielectric element and connected to the
conducting shield.
7. An electro surgical device which comprises a primary driver coil
and a secondary surgical work coil which can be assembled together
with said coils in adjacent but spaced relation and mutually
coupled, the driver coil and the surgical work coil being mounted
in separable elements, a radio frequency power source, a
transmission line connecting the radio frequency power source to
the driver coil, a surgical electrode, means attaching the surgical
electrode to one end of the surgical work coil, and means for
coupling the other end of the surgical work coil to the radio
frequency power source, there being an electrical circuit completed
from the surgical electrode through a patient's tissues and at
least one of the coils by capacitance coupling with the patient
when the surgical electrode is brought into proximity with said
patient's tissues.
8. An electrosurgical device as in claim 7 wherein the transmission
line has a characteristic impedance electrically matched to a
lumped impedance of the primary driver coil, the secondary surgical
work coil, and the patient's tissues.
9. An electrosurgical device as in claim 7 wherein power is
supplied to the radio frequency power source by power leads through
a substantially constant voltage transformer which stabilizes the
radio frequency power source.
10. An electrosurgical device as in claim 7 wherein the surgical
work coil element is hollow and the driver coil element is
releasably received inside the surgical work coil element.
11. An electrosurgical device as in claim 7 wherein the means for
coupling the other end of the surgical work coil to the radio
frequency power source includes interconnecting contacts on the
elements and the transmission line includes means for connecting
the driver coil contact to the radio frequency power source.
12. An electrosurgical device which comprises a driver element
including a driver coil, a transmission line including conductors
connected to opposite ends of the driver coil, means for impressing
a radio frequency oscillating electrical current on the conductors
to energize the driver coil, a handpiece coil in electrically
coupled relation with the driver coil located adjacent to but
spaced therefrom, means for attaching a surgical electrode to one
end of the handpiece coil with a portion of the surgical electrode
exposed, the driver coil inducing a radio frequency oscillating
electrical current in the handpiece coil, there being electrical
coupling between the handpiece coil and a patient when the surgical
electrode is brought into proximity with tissues of the patient.
Description
This invention relates to an electrosurgical device. More
particularly, this invention relates to a multi-purpose
electrosurgical device.
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 separate driver coil coupled
thereto, the radio frequency energy being supplied through a
transmission line from a radio frequency power source.
Briefly, the invention provides an electrosurgical device which
includes a source of radio frequency energy which is coupled to a
driver coil located in a driver element. A handpiece element
includes a second coil which can be removably mounted on the driver
element so that an oscillating current of the same frequency is set
up in the handpiece coil. A surgical electrode is connected to one
end of the handpiece coil. A single electric connection is made
between the handpiece element and the driver element to provide a
ground return pathway for the other end of the handpiece coil. A
capacitance coupling between the body of a patient and the
handpiece coil can supply a return electric path when the electrode
is brought into engagement with or close proximity to the patient's
tissues at an area to be cut or otherwise removed, coagulated or
carbonized.
The above and other objects and features of the invention will be
apparent to those skilled in the art to which the invention
pertains from the following detailed description and the drawings
in which:
FIG. 1 is a view in side elevation of an electrosurgical device
constructed in accordance with an embodiment of this invention;
FIG. 2 is an enlarged fragmentary view in lengthwise section of the
device shown in FIG. 1;
FIG. 3 is a top plan view of a driver element of the device;
FIG. 4 is a top plan view of a handpiece element of the device;
FIG. 5 is a view in enlarged section taken on the line 5--5 in FIG.
2;
FIG. 6 is a fragmentary view in section taken on the line 6--6 in
FIG. 5;
FIG. 7 is a perspective view of a connector ring of the device
before mounting thereof;
FIG. 8 is a fragmentary somewhat schematic view of the device in
association with a patient and a surgical table on which the
patient is disposed, the surgical table being shown in section;
and
FIG. 9 is a schematic wiring diagram for the device.
In the following detailed description and the drawings, like
reference characters indicate like parts.
In FIG. 1 is shown an electrosurgical device 14 which includes a
driver element 16 and a handpiece element 17. The driver element 16
(FIG. 3) includes an outer dielectric tube 18 and a dielectric head
end member 19. A shoulder 20 (FIG. 2) on the member 19 is engaged
by the left-hand end of the tube 18. The member 19 has a lengthwise
bore 21 along which an insulated shielded cable 22 extends. The
bore 21 extends from a left-hand end of the member 19 as shown in
FIGS. 2 and 3 to an opening 24 through which an end portion of the
cable 22 extends into an open chamber 26 inside the tube 18. An
insulated sheath or shield 27 of the cable 22 terminates inside the
chamber 26. The sheath can include a body of woven conducting metal
or the like covered by an appropriate outer coating or cover of
dielectric material. The dielectric cover prevents touching of the
metal of the sheath by the operator or the patient to prevent
injury which might be caused by inadvertent contact with the
conducting sheath. The body of the sheath 27 is grounded in the
electrical portion of the device as shown in FIG. 9. A short lead
28 (FIG. 2) is connected to an end portion of the body of the
sheath 27 inside the chamber 26 and extends outwardly through an
opening 29 in the tube 18 to be attached to a connector ring 31
mounted on the tube 18.
As shown in FIG. 7, the ring 31, before assembly, is provided with
an opening 32 in which the lead 28 (FIG. 2) is attached, as by
soldering. The ring 31 is formed of conductive metal such as copper
or brass. An opening 33 (FIG. 7) in the ring 31 receives a pin 34
(FIG. 2) which holds the ring 31, the tube 18, and the member 19 in
assembled relation. A brass rod 36 is mounted in an axial socket 37
in the member 19 and extends to the right from the member 19 as
shown in FIG. 2. A tubular electromagnetic core 38 is mounted on
the rod 36. A driver coil 39 is wound on the core 38. A first lead
41 from the shielded cable 22 is connected to one end of the driver
coil 39. A lead 42 connects the opposite end of the driver coil 39
to the right-hand end of the brass rod 36. The other end of the rod
36 is attached to a second lead 422 of the shielded cable 22. As
shown, the left-hand end of the socket 37 opens into the chamber 26
to expose the left-hand end of the rod 36. A plug 43 of a
dielectric resin is molded in and closes the right-hand end of the
tube 18. The left-hand end of the member 19 is provided with
circumferential grooves 431 to render it convenient to grip.
Electrical components, to be described in detail hereinafter, set
up an oscillating high frequency potential across the leads 41 and
422 to energize the driver coil 39.
The handpiece element 17 includes an inner tubular member 44 of
dielectric material on which a handpiece or surgical work coil 46
is wound. An exterior dielectric shell 47 surrounds the handpiece
coil 46. A right hand end portion 470 of the shell 47 (FIG. 2) is
flanged inwardly to engage the right hand end portion of the
tubular member 44. The left hand end of the member 44 is flanged
outwardly at 471 to engage the inside of the shell 47. A plug 48 of
dielectric material is disposed inside the right hand end portion
of the tubular member 44. A chuck body 49 is mounted in the plug
48. A lead 51 connects the right hand end of the handpiece coil 46
to the chuck body 49. Chuck jaws 52 are drawn together upon the
shank of a surgical electrode 54 by action of a head 56 threaded on
the jaws 52 so that the surgical electrode 54 is electrically
connected to the right hand end of the handpiece coil 46. A
dielectric cap 57 surrounds the head 56. A screw fastener 58 holds
the shell 47, the tubular member 44 and the plug 48 in assembled
relation. The left hand end of the handpiece coil 46 is connected
to a lead 59. An end portion 61 of the lead 59 is attached to a
contact loop 72 of spring brass or the like. The contact loop 72
extends through openings 73 and 74 in the tubular member 44. Ends
of the loop 72 are soldered together and to the end portion 61 of
the lead 59 by solder 76. When the driver element 16 is disposed
inside a central socket 77 in the probe element 17, the contact
loop engages the ring 31 as shown in FIG. 6 so that the left hand
end of the handpiece coil 46 is connected to the ring 31 and,
through the ring 31, to the shield 27 and ground. The contact ring
31 engages an annular shoulder 78 inside the tubular member 44 of
the handpiece element, and the contact loop is gripped against the
ring 31 at the shoulder 78, the material of the tubular member 44
being resilient and being deformed as shown at 79 to cause firm
engagement between the contact loop 72 and the contact ring 31.
In FIG. 9 is shown schematically the wiring diagram of the device.
Alternating current power is supplied by power leads 111 and 112. A
power line radio frequency interference filter 113 including
condensers 114 and 115 and inductances 116 and 117 greatly
attenuates radio frequency feed-back to the power leads. A power
line fuse 118 is provided in the lead 111.
From the power line filter 113, one lead 119 is connected to one
side of a primary winding 121 of a transformer 122. A second lead
123 from the power line filter 113 is connected to one pole 124 of
a double pole double throw on-off switch 126. The switch 126 is
shown in the on position in full lines. In this position, the lead
123 is connected to a lead 127 which extends to a single pole
single throw interlock switch 128. The interlock switch 128 is
closed during operation of the device but can be arranged to be
caused to open when a casing of the device (not shown) is opened.
The switch 128, when closed, connects the lead 127 to a lead 129
connected to the opposite end of the primary winding 121 to power
the transformer 122. A panel light 130 connected across the leads
119 and 129 indicates that the primary winding 121 of the
transformer 122 is powered. A second pole 131 of the switch 126,
when in the on position, connects leads 132 and 133 to connect one
side of a heater electrode 134 of a tetrode main power amplifier
tube 136 to one side of a first secondary winding 137 of the
transformer 122, which can be constructed to produce approximately
6 volts AC to the heater electrode 134. The other side of the first
secondary winding 137 is connected to ground as is the opposite
side of the electrode 134. A fan motor 1371 is also connected
across the leads 119 and 129 to drive a fan 1372 which blows air on
the tetrode 136 and other components to cool the tetrode and other
components. When the on-off switch 126 is swung to its off
position, the first pole 124 connects the lead 123 to a lead 139
which is connected to one side of a primary winding 141 of a
transformer 142. The other side of the primary winding 141 of
transformer 142 is connected to the lead 119 so that the primary
winding 141 of transformer 142 receives line voltage. One side of a
secondary winding 144 of the transformer 142 is connected through a
lead 145 and the second pole 131 of the on-off switch 126 to the
heater electrode lead 132 so that the heater electrode 134 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. The
secondary winding 144 of the transformer 142 can be arranged to
deliver about four volts so that the heater electrode 134 is heated
but at a lower temperature when the switch 126 is in the off
position but is maintained at a sufficient temperature that the
device will operate at once when the switch 126 is turned on.
A second secondary winding 146 of the transformer 122 suppies a
voltage of approximately 2,000 volts AC across leads 147 and 148 to
a full wave bridge rectifier 149 which supplies 2,000 volts direct
current across leads 150 and 151. The lead 150 is connected to
ground as is a cathode 152 of the tetrode 136. The lead 151 is
connected through a plate choke 153 and a parasitic suppressor
network 154 to a plate 156 of the tetrode 136 so that 2,000 volts
DC is impressed between the cathode 152 and the plate 156 of the
tetrode 136. A filter condenser 157 smooths out wave form ripple
from the rectifier 149. An adjustable resistor 159 and a fixed
resistor 159A are connected in series across the leads 150 and 151.
A lead 158 connected to the tap of the adjustable resistor 159
supplies a positive potential through a resistor 161 and a lead 162
to a screen grid of the tetrode 136. A voltage of approximately 350
volts can be taken off at the tap which is reduced to approximately
300 volts at the screen grid. An appropriate resistance 164 bleeds
off screen grid current to ground. A capacitor 166 connected
between the screen grid lead 162 and ground removes or shunts out
radio frequency from the screen grid.
A section 146A of the second secondary winding 146 of the
transformer 122 is connected in parallel with a capacitor 146B to
form a tuned circuit tuned to a line input frequency, which can be
60 Hertz, to stabilize the secondary winding voltages to a
variation of approximately .+-.1 percent with a change in input
voltage of .+-.15 percent impressed on the primary winding 121.
Thus, the transformer 122 is a substantially constant voltage
transformer stabilizing all the cicuitry of the device.
A bias voltage for a control grid 168 of the tetrode 136 is
supplied by a third secondary winding 169 of the transformer 122. A
first lead 171 from he winding 169 is connected to ground and a
second lead 172 from the winding 169 is connected to a rectifier
173. The rectifier 173 supplies a negative potential through a
resistance 1741 and an inductance 1742 to a lead 174, which is
connected to one end of a first series winding 176 of a transformer
1761. The other end of the winding 176 is connected through a
second series winding 1762 of the transformer 1761 and an
inductance 1763 to a lead 179 connected to the control grid 168 of
the tetrode 136. A condenser 181 which is connected between ground
and a junction 1743 between the resistance 1741 and the inductance
1742 smooths out the wave form of the potential from the rectifier
173. A resistance 183 connected in parallel with the condenser 181
serves to discharge the condenser 181 when the device is turned
off. The bias voltage can be approximately -120 volts.
Oscillator circuits 184 and 186 for the device are powered from a
fourth secondary winding 188 of the transformer 122. Leads 189 and
191 from the winding 188 are connected to a full wave bridge
rectifier 192 which supplies approximately 25 volts DC across leads
193 and 194. A condenser 195 connected across the leads 193 and 194
smooths ripple voltage. A resistance 196 connected across the leads
193 and 194 discharges the condenser 195 when the device is turned
off. The lead 193 is connected to ground. The lead 194 is connected
to one side of a variable potentiometer 202. The other side of the
potentiometer 202 is connected by a lead 204 to a pair of push
button switches 2041 and 2042. The lead 204 is connected to a
contact 2043 of the switch 2042. When the contact bar of the switch
2042 is in the position shown and the push button 2041 is moved to
its other position, the lead 204 is connected to ground. If the
push button 2042 is moved to its other position, it is impossible
to connect the lead 204 to ground.
When the push button 2041 is moved to its other position and the
lead 204 is grounded, a voltage of 25 volts is impressed across the
potentiometer 202 and a selected voltage between zero and 25 volts
is impressed upon a lead 206 connected to the tap of the
potentiometer 202. The lead 206 is connected through an inductance
or choke 207 to the collector of a transistor 208, which is a part
of the oscillator circuit 186. The emitter of the transistor 208 is
connected to the lead 204, which is connected to ground by the
switches 2041 and 2042. The lead 206 is also connected through
resistors 209 and 211 and a rectifier 212 to one side of a tickler
coil 213. The rectifier 212 functions to reverse bias the base of
the transistor 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 a condenser 216 coupled to the transistor 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 the
transistor 208. The rectifier 212 establishes the reverse bias
required by the base of the transistor 208 and is also connected to
the lead 204 through a condenser 217 which establishes the bias
network circuitry. The lead 204 is connected through a bias
rectifier 2171 to a junction between the resistors 209 and 212. The
tank circuit is connected with the emitter and the collector of the
transistor 208 through a coupling condenser 218. A condenser 219 is
connected between the emitter and the collector of the transistor
208 to shunt out radio frequency potentials. A capacitor 777 acts
to provide a bypass to ground shunt for attenuating radio frequency
feed-back into the line 206 when the oscillating circuit 186 is in
operation. The tank circuit can be tuned to oscillate at a rate of
approximately 3.5 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 the lead 179 on the
control grid 168 of the tetrode 136 to provide an amplified output
by the tetrode 136 of that frequency. The output of the tetrode 136
is impressed by way of a lead 220 on a series tuned tank circuit
which includes condensers 221 and 222 and an inductance 223. A
take-off lead 224 which is connected between the condensers 221 and
222 extends to one side of a first matching impedance 226. The lead
422 from the other side of the first matching impedance 226 extends
through the grounded sheath or shield 27 and is connected to one
end of the driver coil 39. The lead 41 also extends through the
sheath 27 to the opposite end of the driver coil 39. The lead 41 is
connected to one end of a second matching impedance 234. The other
end of the second matching impedance 234 is connected to ground.
Thus, a continuous radio frequency oscillating potential is set up
in the handpiece coil 46 and in the electrode 54. The series tuned
tank circuit consisting of the condensers 221 and 222 and the
inductance 223 is matched to the characteristic impedance of the
transmission line consisting of the leads 41 and 422 inside the
sheath 27 through the matching impedances 226 and 234.
When the switch 2041 is moved to its other position to ground the
lead 204, a continuous oscillation is impressed on the coil 39.
When the switch 2042 is moved to its other position while the
switch 2041 is in the position shown and while a double pole double
throw blend switch 2341 is in an off position, at which poles
thereof are in an alternate position, the oscillating circuit 184
is energized to produce an interrupted oscillation in the driver
coil 39. The oscillating circuit 184 is generally similar to the
circuit 186 already described and includes a transistor 237, a tank
circuit inductance 238, a tank circuit capacitor 239, and a tickler
coil 240 and associated elements. A lead 241, which is connected to
the tap of a potentiometer 2411 is connected through a choke 242 to
the collector of the transistor 237. When the switch 2042 is moved
to its other position, a lead 2421 attached to one side of the
potentiometer 2411 is connected to ground. The other side of the
potentiometer 2411 is connected through a lead 2422 and a pole 2423
of the switch 2341 to the lead 194 so that a potential of 25 volts
DC is impressed across the potentiometer 2411 and a selected
potential not exceeding 25 volts is impressed across the lead 241
and the lead 2421 connected to the emitter of the transistor 237 to
set the oscillating circuit 184 in operation to deliver an
oscillator frequency of approximately 3.5 megaHertz on the control
grid of the tetrode 136. The lead 241 is also connected to base
leads of transistors 244 and 246, which form a multivibrator
circuit, through resistors 247 and 248, respectively. The collector
lead of the transistor 244 is coupled through a condenser 249 to
the base of the transistor 246 and the collector of the transistor
246 is coupled through a condenser 251 to the base of the
transistor 244. The collectors of the transistors 244 and 246 are
connected to the lead 241 through resistors 2511 and 2512,
respectively. Emitters of the transistors 244 and 246 are connected
to the lead 2421. The multivibrator circuit can be arranged to
oscillate at a rate of approximately 7,000 Hertz. A lead 252 from
the collector of the transistor 246 is connected through a coupling
condenser 253 to the base of the transistor 237 so that the
operation of the oscillating circuit 184 is interrupted at a rate
of 7,000 Hertz to put an interrupted oscillating potential on the
control grid of the tetrode 136 and to supply an interrupted radio
frequency oscillating potential at the electrode 54.
An adjustable capacitor 1765 is connected between the left hand of
the inductance 1763 and ground and can be adjusted so that it is
series tuned with the inductance 1763 so that the grid input is
tuned with the plate series tuned circuit 221, 222 and 223. Both of
these circuits are tuned with the driver input oscillating circuits
184 and 186 at approximately 3.5 megaHertz. The secondary windings
176 and 1762 of the transformer 1761 combined with a capacitor
2172, which is connected between these secondary windings and
ground, constitute a series tuned circuit which also is tuned to
approximately 3.5 megaHertz.
Loop feed-back coupling capacitors 1776 and 1777 are connected to
winding 1762 through winding 176 and are connected to the bases of
the transistors 237 and 208, respectively, for the purpose of
stabilizing the transistor outputs at low operating levels and to
insure sufficient input base drive for these transistors when
oscillating circuits 184 and 186 are operated at a low voltage
input level, insuring operation of these circuits at such low
voltage potentials.
The switches 2041 and 2042 are so connected that only one of these
switches can be effective to cause operation of one of the
oscillating circuits at any one time and only one of the
oscillating circuits operates at any one time so long as the blend
switch 2341 is in its alternate or "off" position.
When the blend switch 2341 is disposed in its full line or "on"
position, moving of the switch 2041 to its other position energizes
both of the oscillating circuits 184 and 186. The oscillating
circuit 186 is energized in the same manner as already described.
The lead 204, which is connected to ground by movement of the
switch 2041 to its other position is connected through a lead 256
and a pole 257 of the blend switch 2341 to the lead 2421 to connect
the right hand end of the potentiometer 2411 to ground. The lead
2422 from the left hand end of the potentiometer 2411 is connected
through an adjustable resistance 258 to the lead 194 so that a
potential is impressed across the potentiometer 2411 which can be
no greater than 25 volts and which is determined by the setting of
the adjustable resistance 258. A potential is impressed across the
leads 2421 and 241 which is controlled by the position of the tap
of the potentiometer 2411 and by the setting of the adjustable
resistance 258 and lead 206, which is controlled by potentiometer
202 so that both the oscillating circuit 184 and the oscillating
circuit 186 are set in operation and an output is provided from the
tetrode 136 for energizing the electrode 54 which combines the
interrupted oscillation of the circuit 184 with the uninterrupted
oscillation of the circuit 186.
When the device is to be used, an appropriate electrode 54 is
mounted in the chuck jaws 52 (FIG. 2). The blend switch 2341 is
disposed either in the position shown in FIG. 9, at which a blend
of interrupted and uninterrupted oscillations is produced, or in
its other or "off" position at which only one of the oscillating
circuits 184 and 186 can be used at one time. The driver element 16
(FIG. 2) is mounted inside the probe element 17 with the contact
loop 72 engaging the contact ring 31. The main on-off switch 126 is
turned on, and the electrode 54 is moved to a position adjacent or
touching a patient's tissues 301 (FIG. 8) on a surgical table 3011
at a point where electrosurgery is to be performed. The appropriate
one of the push button switches 2041 and 2042 (FIG. 9) is moved to
its other position to provide a radio frequency current flow in the
driver coil 39 which induces a like radio frequency oscillation in
the handpiece coil 46. As the electrode 54 touches or approaches
the body of the patient, an electrosurgical action is provided at
the electrode, and a return electrical path is provided through the
body of the patient 301 and through the air gap between the body of
the patient and the handpiece coil as indicated by dashed
capacitance 302 in FIG. 8. For operative procedures in which
moderate or small power up to approximately 150 watts power input
to the tissues is required, this capacitance between the patient's
body and the probe coil provides a sufficient return electrical
path. However, if greater power over approximately 150 watts power
input to the tissues approaching the maximum power of approximately
400 watts which can be supplied by the device is to be used, it can
be desirable to use an ancillary or passive electrode 303 having a
relatively large area in contact with the body of the patient as
shown in FIG. 8, which is connected through a lead 3031 and
capacitance 304 (FIG. 9) to a ground lead of the device. The
characteristic impedance of the transmission line consisting of the
leads 41 and 422 inside the sheath 27 is matched as closely as
possible to the lumped impedance of the driver coil 39, the
handpiece coil 46 and patient tissue load when the device is used
in cutting, coagulating and dessicating.
When the electrosurgical operation is to be an ordinary or usual
cutting action, the blend switch 2341 is disposed in its other or
"off" position, and the push button switch 2041 is moved to its
other position to set the oscillating circuit 186 in operation and
to provide an uninterrupted oscillation. If a coagulating,
dessicating, or fulgurating action is desired, the push button
switch 2042 is moved to its other position to cause operation of
the oscillating circuit 184 and the multivibrator circuit of the
transistors 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, the blend switch 2341 is moved to its full line
or "on" position, and the switch 2041 is moved to its other
position to cause delivery of a blending of interruped and
uninterrupted oscillations.
The power delivered by the oscillating circuit 184 can be adjusted
by movement of the tap of the potentiometer 2411. The power
delivered by the oscillating circuit 186 can be adjusted by
movement of the tap of the potentiometer 202.
With the structure of this invention, a number of probe or
handpiece elements can be employed with a single driver element,
and change of handpiece elements can be rapidly and conveniently
effected.
In the device as shown, the handpiece coil surrounds the driver
coil and the return electrical path from the patient's tissues is
chiefly to the handpiece coil, but, if desired, part or all of the
driver coil can be extended outside the handpiece coil to permit a
return electrical path to the driver coil.
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.
* * * * *