Ground Electrode And Test Circuit

Abstract

An electrical-surgical machine using high-frequency currents connected to an active electrode and a patient ground plate electrode. The ground plate electrode is a one-piece disposable flexible sheet member having an electrical conductive skin releasably attached to a clamp connected to a line leading to the electrical-surgical machine. A circuit-testing unit checks the entire circuit, including the electrical connection between the patient and ground plate electrode, as well as the electrical connection between the clamp and the ground plate. The releasable clamp has a pair of spaced flat electrical contacts in surface engagement with the electrical conductive skin of the ground electrode. One form of the clamp has a pair of plate contacts attached to and pivotally mounted on flat electrically insulative covers.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. Pat. application Ser. No. 762,582 filed Sept. 25, 1968.

Description

BACKGROUND OF INVENTION

In 1907, Pozzi demonstrated fulguration as a cure for malignant disease to the Paris Academy of Medicine, using an Oudin resonator and unipolar current of a frequency around half a million cycles per second. His results were by no means uniform, and it was left to Iredell and Turner, in 1919, to demonstrate true diathermy by providing a plate, 6 by 12 inches, for the return circuit. They showed that the effects of the treatment were entirely due to heat destruction of tissues and were first to use a water pipe to ground both the indifferent electrode and the patient. This contribution to safety has remained until the present day. In use, heat is developed at both the active electrode and the indifferent or ground electrode, commonly a lead plate, in surface contact with the skin of a patient. The heat generated is inversely proportional to the square area of these electrodes. The ground electrode must be of a certain size and has to make uniform contact all over its surface so that the heat is diffused over a wide area. If the ground electrode has point contacts, the patient can be severely burned. In some instances, two ground electrodes are used at the same time to insure adequate grounding of the patient.

Efficient functioning and safety of electrical-surgical machines depends upon an unimpaired return of current via the indifferent ground electrode and its cable. If this fails, then the current will choose the next best route, which will mean a short circuit to ground with a consequent risk of a diathermy burn. Some machines are equipped with a ground test stud that requires the operating staff, before each operation, to check the circuit. This system only monitors the continuity of the cable and its attachment to the ground electrode. It does not monitor the electrical contact and conductivity between the ground electrode and the patient.

Various materials are used for the ground plate electrodes. The material should be a good conductor and easily malleable. Lead plates have been the most practical to use. Some plates have been made of stainless steel, zinc and tin, as suggested by Ruben, U.S. Pat. No. 1,973,911, and Wappler, U.S. Pat. No 1,662,446.

Copending U.S. Pat. application, Ser. No. 711,949, now U.S. Pat. No. 3,543,760 describes a disposable ground plate electrode and clamp usable with an electrical-surgical unit for cautery, fulguration, electrocoagulation, and like surgical procedures. This ground plate electrode has a continuous electrical conductive aluminum skin secured to an insulated base. The clamp has a substantially flat surface adapted to be positioned in surface engagement with the aluminum skin to insure an effective electrical connection between the clamp and the electrical conductive skin of the ground plate. This ground plate electrode cannot be used to check the electrical conductivity between the electrode and the skin of the patient.

SUMMARY OF INVENTION

The invention relates to an electrical continuity testing circuit to test the electrical connections between a clamp and a ground plate electrode and electrical conductivity between the ground plate electrode and the patient, as well as the circuit of a cable attached to the clamp. The ground plate electrode is a disposable sheet member having an electrical conductive skin which can be separated in two sections. The clamp has a pair of spaced electrical contact members with flat surfaces clamped into surface engagement with the separate sections of the ground plate electrode. One form of the clamp has cover members which support and insulate the electrical plate contacts. The test circuit uses low-voltage power and an indicator to check the electrical contact between the clamp and ground plate electrode and the continuity of the cable between the clamp and electrical-surgical machine. One form of the test circuit uses a split ground plate electrode with a bipolar clamp in a circuit test loop, including a battery and meter to check the electrical resistivity between the patient and ground plate electrode. In another form of the test circuit, the circuit includes a control operative in response to a completed test circuit to automatically connect the ground plate electrode to a high-voltage circuit.

IN THE DRAWINGS

FIG. 1 is a diagrammatic view of the electrical-surgical unit equipped with the ground plate electrode and connector of the invention used on a patient lying on an operating table;

FIG. 2 is a perspective view of the releasable connector attached to an edge of the ground plate electrode;

FIG. 3 is a side view of one form of the connector of FIG. 2, partly sectioned, in assembled relation with a ground plate electrode;

FIG. 4 is an electrical diagram of a test and control circuit, bipolar clamp, and ground plate electrode;

FIG. 5 is a plan view, with parts broken away, of another form of the connector;

FIG. 6 is an enlarged sectional view taken along the line 6--6 of FIG. 5;

FIG. 7 is a diagrammatic view of an electrical-surgical unit having a split ground plate electrode attached to a bipolar clamp connected to a circuit testing unit;

FIG. 8 is an enlarged sectional view taken along the line 8--8 of FIG. 7;

FIG. 9 is an enlarged sectional view taken along the line 9--9 of FIG. 7;

FIG. 10 is a side view, partly sectioned, of the bipolar clamp of FIG. 7;

FIG. 11 is an enlarged plan view of the circuit testing unit and cable male connector;

FIG. 12 is an electrical diagram of the testing circuit, bipolar clamp, and split ground plate electrode of FIG. 7;

FIG. 13 is a plan view of a split ground plate electrode having a clamp locator hole with parts broken away;

FIG. 14 is a plan view of a bipolar clamp attached to a split ground plate electrode;

FIG. 15 is a side view of the clamp;

FIG. 16 is an enlarged sectional view taken along the line 16--16 of FIG. 15;

FIG. 17 is an enlarged sectional view taken along the line 17--17 of FIG. 14;

FIG. 18 is an enlarged sectional view taken along the line 18--18 of FIG. 14; and

FIG. 19 is a sectional view similar to FIG. 17 showing a modification of the clamp.

Referring to the drawings, there is shown in FIG. 1 an electrical-surgical unit, indicated generally at 10, illustrated in an operating environment theater on a patient 11 lying on a table 12. Table 12 is supported on floor 13 by an upright base 14 to locate the patient in a convenient position for surgeon 16.

The electrical-surgical unit 10 uses high-frequency current from a portable transformer 17 connected to power supply lines 18 and to an active electrode 19 by a cable or line 20. The circuit through the patient 11 is completed with a ground plate electrode 21 located in contact with an area of the skin of the patient. A line or cable 22 is connected to the electrode 21 through a releasable connector or clamp, indicated generally at 23. Connector 23 is clamped to the ground plate electrode 21 to complete the electric circuit to the transformer 17. The opposite end of line 22 is connected to a test and control circuit, indicated generally at 24, carried by the transformer 17. In use, the surgeon 16, prior to operative use of the active electrode 19, will visually observe a light 63 on the test and control circuit to see if the releasable connector 23 is in electrical contact with the ground plate electrode 21 and determine if high voltage is present in the operating circuit.

Referring to FIGS. 2 and 4, there is shown the disposable ground plate electrode 21 as having a flat base 26 covered with an electrically conductive skin 27. Plate 21 has an end flange or flap 28 folded over forming a stop edge 29. The base can be impregnated with a plastic material which bonds the skin 27 to the top of the base. The skin is an electrically conductive material, as sheet metal or aluminum foil. The ground plate electrode 21 is described in detail in copending U.S. application Ser. No. 711,949, filed Mar. 11, 1968, now U.S. Pat. No. 3,543,760.

The releasable connector 23 functions to provide an electrical connection between the cable 22 and the ground plate electrode 21. Connector 23, shown in FIGS. 2 and 4, has a C-clamp 31 pivotally carrying a pair of angularly disposed levers 32 and 33. As shown in FIG. 2, lever 32 has separated contact plates 34 and 36 and rearwardly directed conductor arms 34A and 36A separated with plastic or other nonelectrically conductive material 37. Lever 33 may have similar separated plates formed with a rearwardly directed lip 38A to hold the contact plates 34 and 36 in flat surface engagement with the electrically conductive skin 27 of the ground plate electrode 21.

Referring to FIG. 3, there is shown a modified conductor 23A having a plate 36A carrying a downwardly directed projection or finger 39 extended through a hole 41 in plate electrode 21 and hole 42 in the lip 38A. The other contact plate 34 may also have a similar projection or finger located in aligned holes in plate electrode 21 and the separated bottom lip. The center of the clamp between plates 34 and 36 can be made with a projection adapted to pass through a center hole in the ground plate. The projections positively lock the releasable connector 23A to the ground plate electrode 21 so that it cannot be accidentally removed or partially separated from the plate electrode 21.

The entire connectors 23 and 23A and exposed portions of the levers 32, 32A and 33, 33A are coated with a plastic insulative material so that the connectors cannot short out the ground plate electrode 21 causing burning of the patient. The lines 43 and 44 from the cable 22 are connected to the terminal portions of the conductors 34A and 36A, respectively, as shown in FIG. 2.

Referring to FIG. 4, there is shown connector 23 in assembled relation with the ground plate electrode 21 along with the test and control circuit 24. The transformer 17 provides the circuit 24 with a low-voltage source 46 and a high-voltage source 47. Line 48 connects a coil 49 of a relay 51 to the low-voltage source 46. The coil 49 is connected to line 43 leading to the conductor arm 34A. A manually operated control switch 52 interposed in the line 48 between the coil 49 and the low-voltage source 46 controls the circuit for the low test voltage and the circuit for the high voltage. The low-voltage circuit is completed with a line 53 connected to the line 44 leading to the opposite conductor arm 36A of the connector 23. Relay 51 has three contacts 54, 55, and 56, and a pair of movable switching elements 57 and 58 operably associated with the coil 49. Switching element 57 is connected with a line 59 to the line 43. Switching element 58 is connected with a line 61 to the line 44. The contact 54 is connected to a line 62 which leads to the low-voltage line 48. A light 63 is interposed in the line 62 to indicate an improper or insulated electrical connection between the connector 23 and ground electrode 21. The light 63 may be replaced with an electrically operated sound-producing device or other signal means to provide a sensing signal indicating a defective electrical connection between the connector 23 and the ground electrode 21. Both contacts 55 and 56 are connected to the high-voltage line 64 to complete one line of the high-voltage circuit. The high-voltage circuit is completed through the patient 11, the ground electrode 21, and line 20.

In use, the switch 52 is closed connecting the low-voltage source 46 to the connector 23. With the relay 51 in its normal position, the switching elements 57 and 58 are out of engagement with the contacts 55 and 56. The element 58 engages the contact 54 closing the circuit to the light 63. When the light 63 is "on," there is nonelectrical contact between the connector 23 and the electrode 21 in that current does not flow via the ground electrode 21 between the contact plates 34 and 36. When the connector 23 is in proper electrical contact with the electrode 21, the low-voltage circuit is completed through the plates 34 and 36 via the electrical conductive skin 27 to energize the coil 49. This moves the switching elements 57 and 58 into engagement with the contacts 55 and 56 thereby opening the circuit to the light 63 and closing the high-voltage circuit to the connector 23. Both contact plates 34 and 36 are connected in the high-voltage circuit by virtue of the two switching elements 57 and 58. The high-voltage circuit is completed through the active electrode 19, the patient 11, and the cable 20.

Referring to FIGS. 5 and 6, there is shown the modified flat connector, indicated generally at 66, for connecting the line 22 to the disposable ground plate electrode 21. The connector 66 has a pair of identical clamp contact members 67 and 68 formed from conductive material, as sheet metal. The contacts 67 and 68 are enclosed in and secured to flat identical covers 69 and 71 of electrically insulative material, such as plastic and the like. The contact members 67 and 68 are identical in structure and are located in spaced side relation in the cover to form a bipolar connector.

As shown in FIG. 6, clamp contact member 67 comprises a pair of conductor members 72 and 73 having engaging transverse ribs 74 and 76 secured together, as by spot welds, to form a one-piece clamp. The center or body sections 77 and 78 of the members curve outwardly to form a transverse chamber 79. The forward portions of members 72 and 73 are flat contact plates 80 and 81 which are biased together by the curved sections 77 and 78. Projected upwardly from the front and rear edges of the sections 80 and 81 are pairs of upright ears 82 and 83 securing the plates 80 and 81 to the covers 69 and 71. The forward or front edges of the plate contacts 80 and 81 have transverse outwardly directed flanges 84 and 86 extended over the front side of cover walls 87 and 92, respectively. Flange 84 is located in a transverse groove 89 along the front side of wall 87.

Located on opposite sides of the wall 87 are holes 88 for accommodating the ears 82. Wall 87 forms the bottom of the recess 90 in the cover 69 which is closed with a strip closure 91 mounted on the cover flush with the flat outer side of the cover 69. The member 72 is fastened to the wall 87 by turning the ears 82 over the top of the wall 87. Member 73 is attached to the wall 92 in a similar manner. The ears 83 project through holes 93 in the cover on opposite sides of the wall 92 with the forward flange 86 located in a transverse groove 94. The cover 69 has a recess 96 for the turned over ears 83 which is closed with a strip closure 97 mounted on the cover flush with the flat outer side of the cover 71.

With the members 72 and 73 secured to the walls 87 and 92, respectively, the transverse curved bodies 77 and 78 are in transverse engagement along bearing or fulcrum lines 98 and 99 with transverse midportions of the covers 69 and 71. The lines 98 and 99 extend along the midsection of the covers rearwardly of the walls 87 and 92, so that upon movement of the covers 69 and 71 toward each other in the direction of the arrows 100, the covers 69 and 71 will fulcrum along the fulcrum lines 98 and 99 spreading the plate contacts 80 and 81, whereby the ground plate electrode 21 may be inserted between the plate contacts 80 and 81. The biasing action of the curved sections 77 and 78 will hold the plate contacts 80 and 81 in flat surface engagement with opposite sides of the ground plate electrode 21.

The peripheral edges of the covers 69 and 71 have inwardly directed side and end flanges 101 and 102 located in a relative lapped relation so that the covers can be moved toward each other and enclose the electrical connections of the lines 43 and 44 to the clamp contact members 67 and 68, respectively.

As shown in FIG. 6, the front edges of the covers 69 and 71 have forwardly projected and outwardly tapered nose portions 103 and 104 which provide rearwardly converging guide surfaces leading to the plate contacts 80 and 81. The nose portions 103 and 104 extend transversely parallel to the plate contacts 80 and 81 and are separated from each other forming a mouth 94.

Referring to FIG. 7, there is shown a diagrammatic view of an electrical-surgical unit, indicated generally at 106, connected to a split ground plate electrode 107 with a cable 108 and a releasable bipolar clamp, indicated generally at 109. The cable 108 connects the clamp to a circuit testing unit 111 plugged into the electrical-surgical unit 106. The electric circuit through the patient is completed by the use of an active electrode coupled to a cable extended back to the electrical-surgical unit 106, as illustrated in FIG. 1.

The ground plate electrode 107 is a rectangular-shaped one-piece sheet member having a transverse flap or scored end 112 cooperating with the clamp 109 to prevent the accidental disengagement of the clamp from the ground plate electrode. The corners 113 and 114 are curved or arcuate to eliminate sharp points and edges which may cut the patient or personnel in the operating theater.

As shown in FIG. 8, the ground plate electrode 107 has a flat and flexible base 114 which may be made of cardboard, paper, or similar flexible and electrically insulative material. Secured to the top of the base 114 is a pair of spaced electrically conductive skins 116 and 117 having flat and smooth surfaces. The skins 116 and 117 are located in a side-by-side relation and are separated from each other by a longitudinal space 118 extended down the longitudinal centerline of the ground plate electrode 107. The skins 116 and 117 may be sheet material or metal foil, as aluminum foil, bonded to the base 114. The skins have smooth continuous top surfaces and outer peripheral edges 119 that are turned down into the adjacent edges of the base 114. The turned down edges 119 provide rounded edges around the entire ground plate, thereby eliminating any sharp edges which may injure the patient or operating personnel. The base 114 is impregnated with a plastic material which bonds the skins 116 and 117 to the top of the base. Other chemicals and materials can be used to treat and liquid-proof the base. The plastic material increases the thermal characteristics of the ground plate electrode 107 so that it can be placed in an autoclave for sterilization. In addition, the plastic material makes the entire ground plate electrode liquid-proof. The plastic material functions to maintain a continuous bond between the skins and the base so that the electrode may be flexed and wrapped around a patient without separating the skin from the base or cracking the base. The back side of the base can be printed with instruction and inventory code information with ink that does not run or react with liquids or change with heat.

A specific example of the bipolar ground plate electrode 107, usable as a disposable electrode with an electrical-surgical unit, is as follows. The base 114 is a cardboard sheet member having rectangular dimensions of 8 by 13 inches. The base is electrically insulative cardboard about 0.024-0.022 inch thick. The skins 116 and 117 are 0.003 inch aluminum foil bonded with plastic material to the top of the base. The base 114 is entirely impregnated with plastic material. The longitudinal center space 118 extends the entire length of the electrode, including the flap 112. The space has a width of 3/8 to 1/2 inch. The rounded corners have a radius of 1 inch and the flap has a width of 1/2 inch. Other sizes and shapes of the ground plate electrode and the skins 116 and 117 are intended to be within the scope of the invention.

The bipolar clamp 109 has an elongated C member of split cylinder 121 pivotally carrying a pair of converging levers 122 and 123. The levers extend through circumferentially spaced slots (not shown) in the back of the cylinder. Forward portions of the levers engage the transverse open edges of the split cylinder which biases these portions together. The part of the lever 122, projected forwardly from the cylinder 121, has a first flat contact nose or plate 122A and a second contact nose or plate 122B separated from the first contact plate with an electrically insulative strip 124. The strip 124 separates the lever 122 into separate electrical conductors. The lower lever 123 is also separated into two electrical conductors, each having rearwardly directed legs 123A and 123B separated from each other with an electrically insulative strip 125. The legs 123A and 123B have flat upper surfaces that face the flat contact surfaces of the plates 122A and 122B.

Projected downwardly from the forward portion of the insulation strip 124 is projection or pin 126 which extends through a hole 127 in the ground plate electrode 107 and a hole 128 in the insulation strip 125 of lever 123. The hole 127 is located in the space 118 of the ground plate electrode 107 adjacent the flap 112. Plates 122A and 122B can each be provided with a projection or pin adapted to extend through suitable spaced holes in the ground plate electrode. The use of two pins prevents rotation of the clamp relative to the ground plate electrode. The entire clamp 109, except for the contact plates 122A and 122B and corresponding surfaces on the legs 123A and 123B, is coated with an electrically insulative material, as an electrically insulative plastic. This coating prevents the grounding of the patient through the clamp and thereby avoids any contact burns.

The clamp 109 is releasably attached to the ground plate electrode 107 by compressing the outer ends of the levers 122 and 123 to open the mouth of the clamp by separating the contact plates 122A and 122B from the legs 123A and 123B. The ground plate electrode 107 with the flap 112 in the folded position, as shown in FIG. 10, is inserted into the clamp. The middle of the clamp 109 is aligned with the space 118 by aligning the projection 126 with the hole 127 and the ground plate electrode 107. This positions the contact plate 122A in flat surface engagement with the skin 116 and the contact plate 122B in surface engagement with the skin 117. The projection 126, by extending through the hole 128 in the lower lever 123, prevents the accidental removal upon disengagement of the clamp 109 from the electrode 107. The only way the clamp 109 can be removed from the electrode 107 is to depress and open the clamp to remove the projection 126 from the electrode 107. The purpose of aligning the bipolar clamp 109 so that one electrical contact portion 122A engages one skin 116 and the other contact plate 122B engages skin 117, is to provide a structure and electrical circuit capable of monitoring the efficiency of the electrical conductivity between the ground plate electrode 107 and the skin of a patient, as well as the electrical connection between the clamp 109 and the ground plate electrode 107 and the continuity of the cable 108. The circuit testing unit 111 functions to form these tests.

Referring to FIG. 11, there is shown the circuit testing unit 111 separated from the electrical-surgical unit. The testing unit 111 has a housing or casing 131 enclosing the electrical test circuit. Secured to one end of the housing is a male plug adapted to be inserted into a complementary receptacle in the electrical-surgical unit to electrically connect the testing circuit with the electrical circuit of the unit 106. The opposite end of the housing 131 carries a female receptacle 133 for receiving a male connector 134 secured to the end of the cable 108.

Exposed on the top of the housing 131 is an information scale or indicia 136 which is indicative of the continuity of the circuit. The scale is marked open, good, and short. Other indicia, as verbal, numerical, color and the like, may be used to indicate the electrical condition of the circuit. Associated with the scale is a movable pointer or finger 137 which moves in response to the electrical circuit characteristics. Located below the scale is a movable switch button 138 operative to switch the main ground circuit to the test circuit. The top of the housing 131 also contains an adjustable screw or member 139 used to calibrate the test circuit and compensate for the changes in the strength of the test battery.

Referring to FIG. 12, there is shown the electrical circuit, indicated generally at 141, between the ground plate electrode 107 and the terminals 144A and 144B on the electrical-surgical unit 106. The circuit includes the active electrode 142 connected with a line 143 to the terminal 144A. The ground plate electrode 107 is connected with a line 146 to the terminal 144B. This line 146 provides a continuous ground for the electrode 107. The line 146 is connected to one side of the lever 122. A second line 147 is connected to the opposite side of the lever 122 whereby both electrical conductive portions of the lever 122 are connected to the electrical-surgical generator. Interposed in line 147 is a switch, indicated generally at 148. The switch 148 has a first pair of contacts 151 and 152 connected to the line 147. The manually operated button 138 is connected to a movable bar or contact 156 which is normally engageable with the contacts 151 and 152 to complete the circuit through line 147. A spring 149 continuously biases the switch 148 to the closed position electrically connecting the contacts 151 and 152. As soon as the pressure or force is relieved from the switch button 138, the switch 148 will automatically return to the closed portion.

Switch 148 has a second pair of contacts 153 and 154 adapted to be engaged by the movable contact 156 upon depression of the button 138. Contact 153 is located in a line 157 connected to the line 147 between the contact 151 and the clamp 109. A battery 158, as a low-power 9-volt DC battery, is connected to the line 146 with a line 159. The battery 158 is also connected to a variable resistance 161 which is adjustable with the screw 139 to calibrate the electrical output of the battery. A line 162 connects the variable resistance 161 to a galvanometer or similar instrument for measuring the electrical current in a circuit. The meter 163 is connected with a line 164 to the switch contact 154. Upon depression of the button 139, the bar 156 engages the contacts 153 and 154, as shown in broken lines, to complete the test circuit to the meter 163 and the skins 116 and 117. The test circuit 141 functions to test the continuity of the lines or cable 108 between the unit 111 and the clamp 109, the electrical connection between the clamp contact plates 122A and 122B and the corresponding electrical conductive skins 116 and 117, and the electrical surface connection or resistivity between the skin portion of a patient, indicated at 166 in FIGS. 7 and 12, in surface engagement with both of the skins 116 and 117. The meter 163 will indicate a lack of effective electrical contact between the patient's skin and the electrical skin conductors 116 and 117. When the indicator or pointer 137 is in the open position, as shown in FIG. 11, the contact between the patient and the ground plate is insufficient to have an effective operation of the active electrode. When the pointer 137 is in the short range, the circuit is grounded. This may indicate an improper positioning of the clamp on the ground plate electrode so that a single contact plate, as plate 122A, engages both electrically conductive skins 116 and 117. An open circuit may indicate a break in the cable or electrical connection between the cable and the clamp, or an insufficient electrical connection between the clamp and the ground plate electrode.

When the test circuit indicates an open or insufficient electrical connection between the patient 166 and the ground plate electrode, it may be necessary to reposition the electrode on the patient or add electrically conductive jelly, or other conductive material, to increase the electrical connection between the patient's skin and the ground plate electrode. It may be necessary to reposition the clamp on the electrode to insure a surface contact between the contact plate 122A and skin 116 and contact plate 122B and skin 117.

Referring to FIG. 13, there is shown a ground plate electrode 167 having a generally rectangular shape. Electrode 167 has a flexible base 168 which can be made of cardboard, paper, wood, and similar material. The base is substantially flat, flexible, and electrically insulative. Attached to the top of the base 168 is a pair of substantially identical electrical conductive skins 169 and 171. The skins are spaced from each other along the longitudinal centerline of the base with a uniform longitudinal space 172. The skins 169 and 171 are electrically conductive sheet members having flat continuous and smooth top surfaces. The skins 169 and 171 may be made of sheet metal, metal foil, and like electrically conductive material, as aluminum foil. The skins can be bonded or secured to the top of the base 168 with an adhesive or plastic material embedded in the base 168. Other chemicals, bonding and adhesive materials can be used to treat and liquid-proof the base, as well as bond the skins 169 and 171 to the base 168. The treatment of the base increases its thermal characteristics, as well as its resistance to chemical action and liquids, as water, blood, and like. The peripheral edges of the ground plate are rounded to eliminate any sharp edges which may injure a patient or operating personnel, as shown in FIG. 8 of the drawing.

One end of the ground plate electrode has a flap or flange 173 extended across the end of the electrode and defined with a crease or fold line 174. The crease 174 permits the easy and convenient folding of the flap prior to insertion into the clamp. The corners 176 and 177 of the opposite end of the electrode are rounded or curved to eliminate any sharp points or edges. Inwardly of the flap 173 in the midsection of the base 168 is a clamp locator hole 178. The electrode 167 can be provided with two other holes 178A and 178B for the purpose of locating and holding the clamp on the electrode.

The clamp, indicated generally at 179, is a bipolar connector operative to make separate surface electrical connections with the skins 169 and 171. As shown in FIG. 14, clamp 179 is connected to a two-line cable 180 leading to the circuit test unit and electrical-surgical machine. As shown in FIG. 15, the clamp 179 comprises a pair of identical generally flat lever members 180 and 181 which are pivotally connected together in a manner so that the front sections thereof are biased together. Lever members 180 and 181 have front relatively flat portions 182 and 183 and upwardly and outwardly directed rear portions 184 and 186, respectively. The rear portions 184 and 186 diverge from each other from a transverse pivot rod 187. The sides of the lever members have inwardly directed side flanges 185. Each lever member 180 and 181, including the ears, rib, and side flanges, is a one-piece nonelectrical conductive plastic member resistant to heat and liquids, as blood and water. Materials other than plastic can be used to make the lever members. The obtuse angular shape of the lever members 180 and 181 enable the clamp to open wide for cleaning and attachment to the ground plate electrode.

As shown in FIG. 16, each lever member has a plurality of laterally spaced downwardly projected ears 188 and 189 which have end portions that overlap each other to accommodate the transverse pivot rod 187. Rod 187 is made of electrical insulative material. Rod 187 can be separated into two parts with the center portions of the parts spaced from each other. The forward portions 182 and 183 of the lever members are biased toward each other by a pair of torsion coil springs 192 and 193 telescoped over opposite end portions of the rod 187. Each spring has a pair of ends 192A, 192B, and 193A, 193B, which extend outwardly from the pivot rod 187 and engage the inside portions of the electrical conductors 195A and 196A and 194A and 194B mounted on the lever members and thereby continuously bias the front portions 182 and 183 into engagement with each other. The springs 192 and 193 provide electrical connections between adjacent upper and lower flat conductors 195A, 196A and 194A, 194B. Lever portions 184 and 186 have short projections or stubs 184A and 186A projected inwardly to retain conductors 195A and 196A in assembled relation with the lever members. Additional projections are used to hold conductors 194A and 194B. Cable 180 has a first line 180A connected to conductor 194A and a second line 180B connected to conductor 195A.

Returning to FIG. 14, the clamp 179 has a pair of spaced electrical contact plates 194 and 195 in surface engagement with the electrically conductive skins 169 and 171. Plate 194 is only in surface engagement with the skin 169 and plate 195 is only in surface engagement with the skin 171. The adjacent ends of plates 194 and 195 are spaced from each other a distance greater than the space 172 so that a single contact plate does not engage both skins 169 and 171. Preferably, this distance is approximately one inch. As shown in FIG. 17, the contact plate 195 is clamped onto a flat transverse rib 197. The rib 197, extended across the inside of the front portion 182, has a front transverse groove 198 and a rear transverse step 199. Plate 195 has a turned front terminating in a transverse edge 195B located in the groove 198. The rear portion of the plate 195 is offset, located adjacent step 199, and joined with conductor 195A. Plates 194 and 196 are attached to their ribs in the same manner. The rib 197 extends downwardly or inwardly from the inside face of the lever member 180 to form a space or pocket 201 to accommodate the flap or flange 173. The lever member 181 has a similar rib for carrying the contact plate 195 so that the pocket 201 has a large transverse space between the front portions 182 and 183 of the lever members.

Referring to FIG. 18, there is shown the lever member 180 having a downwardly directed projection or pin 202 integral with the midportion of the rib 197. The projection 202 extends through the hole 178 in the ground plate electrode and into a hole 203 in the lever member 181. The projection 202 provides a positive coupling of the clamp 179 to the ground plate electrode 167. The clamp cannot be accidentally removed without spreading the lever members 180 and 181. By locating the hole 178 in the base 168 within space 172, the electrical contact plates 194 and 195 are aligned with their respective electrically conductive skins 169 and 171. The clamp can have a pair of spaced pins or projections adapted to extend through holes 178A and 178B in the electrode 167. These projections can be secured to the plates 194 and 195 or extend through holes in these plates. The use of two spaced projections prevents rotation of the clamp relative to the electrode, as well as accidental removal of the clamp from the electrode.

FIG. 19 shows the forward portion of a modified clamp, indicated generally at 179A. The clamp 179A is identical with the clamp 179, except for the elimination of the projection or pin 202. The electrode 167 is retained in the clamp 179A by folding the flange 173 along the fold line 174. In this manner, the forward edge of the flange will cooperate with the rib 197A to prevent the accidental disengagement of the electrode 167 from the clamp. The folded portion of the electrode is located in the transverse space 201A between the lever portions 182A and 183A.

While there have been shown and described preferred embodiments of the ground plate electrode, the clamp releasably attached to the ground plate electrode, and the circuit-testing apparatus for monitoring the electrical characteristics of the ground plate electrode and connections thereto, including the resistivity between the patient and ground plate electrode, it is to be understood that various changes, substitutions, and deletions may be made by those skilled in the art without departing from the spirit of the invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination: an electrode having a base and electrically conductive skin means secured to at least one side of the base, clamp means releasably attached to a portion of the electrode, said clamp means having at least two separated electrical contact members, means to hold the contact members in surface engagement with separate portions of the electrically conductive skin means, and means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode, and electric circuit means connected to the contact members of the clamp means for testing the electrical connections between the electrically conductive skin means of the electrode and the separate contact members of the clamp means, said circuit means adapted to be connected to a source of electric power to provide electric energy to the circuit means to test said electrical connections.

2. The combination of claim 1 wherein: the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprise means on said clamp means engageable with a turned flange of said electrode.

3. The combination of claim 1 wherein: the circuit means comprises a low-voltage circuit connected to and completed through said contact members and electrically conductive skin means, a relay having a coil and switch contacts, said coil located in said low-voltage circuit, a high-voltage circuit containing said switch contacts and connected to the contact members of the clamp means whereby when the low-voltage circuit is completed in the coil, it is energized closing the switch contacts to complete the high-voltage circuit to the electrode.

4. The combination of claim 3 wherein: the low-voltage circuit includes signal means providing a recognizable indication when the high-voltage circuit is open.

5. The combination of claim 1 wherein: the circuit means has a first circuit connected to the separate contact members, a second circuit connected to at least one of the contact members, and means operable on completion of the first circuit to close the second circuit.

6. The combination of claim 5 wherein: the first circuit is a low-voltage circuit and the second circuit is a high-voltage circuit.

7. The combination of claim 5 wherein: the means operable on completion of the first circuit to close the second circuit includes relay means having a control element in the first circuit and switches in the second circuit operable by the control element so that on completion of the first circuit the control element will close the switches thereby closing the second circuit.

8. The combination of claim 1 wherein: said electrode has hole means and the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprise projection means extended through said holes means.

9. The combination of claim 1 wherein: the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprise at least one projection extended through a hole in the electrode and cooperating with the contact members to hold the clamp means in assembled relation with the electrode.

10. The combination of claim 1 wherein: the clamp means has a cover means located over the contact members, said contact members secured to a portion of the cover.

11. In combination: an electrode having a base, a first electrically conductive skin and a second electrically conductive skin spaced from the first skin, said first and second skins secured to said base and adapted to contact a body, clamp means releasably attached to a portion of the electrode, said clamp means having first electrical contact means engageable with the first skin and second electrical contact means engageable with the second skin, means holding the first and second contact means in engagement with said skins, and means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode, and electric circuit means connected to the first and second contact means of the clamp means for testing the electrical connections between the electrically conductive skin means of the electrode and the separate contact means of the clamp means and for monitoring the electrical conductivity of the electrical connections between a body and the portions of the first and second skins in engagement with the body, said circuit means adapted to be connected to a source of electric power to provide electric energy to the circuit means to test said electrical connections.

12. The combination of claim 11 wherein: the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprise means on said clamp means engageable with a turned flange of said electrode.

13. The combination of claim 11 wherein: said circuit means includes an electric power source, a meter connected to the power source, and a switch operable to couple the meter and power source in series with the first skin and second skin.

14. The combination of claim 13 wherein: said power source is a battery and said test circuit includes a variable resistance operable to calibrate the power output of the battery.

15. The combination of claim 11 wherein: the circuit means includes a line that continuously connects at least one conductive skin to ground and a test circuit for monitoring the conductivity of the electrical connection between the patient and the portions of the first and second skins in engagement with the patient.

16. The combination of claim 11 wherein: said clamp means has a first lever with a forward portion connected to the first contact means and the second contact means, a second lever, means pivotally connecting the first lever with the second lever, and biasing means urging forward portions of the first lever and second lever toward each other.

17. The combination of claim 16 wherein: the first lever has a generally flat forward portion and an upwardly and outwardly directed rear portion.

18. The combination of claim 11 wherein: the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprise at least one projection extended through a hole in the electrode when the clamp is attached to the electrode.

19. The combination of claim 18 wherein: the clamp means has two spaced projections extended through spaced holes in the electrode when the clamp is attached to the electrode.

20. The combination of claim 11 wherein: said circuit means includes an indicator means operable to provide a readable signal in response to the electrical connections between the electrical contact means and the first and second skins and the electrical connection between the body and the first and second skins.

21. The combination of claim 20 wherein: said indicator means is an electrical meter.

22. The combination of claim 11 wherein: the means cooperating with the electrode to prevent accidental separation of the clamp means from the electrode comprises at least one projection extended through a hole in the electrode between the first skin and the second skin when the clamp means is attached to the electrode, said projection being located between the first contact means and second contact means, whereby the projection aligns each contact means with a skin.

23. The combination of claim 11 wherein: the first skin and the second skin are longitudinally aligned relative to each other and secured to one side of the base, said skins being separated from each other along the longitudinal center of the electrode.