US 3741219 A
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United States Patent 1 Sessions GROUNDING PLACE OR ELECTRODE FOR ELECTROMEDICAL EQUIPMENT  Inventor: Robert W. Sessions, German Church Road, Hinsdale, Ill.
 Filed: Nov. 24, 1971 211 Appl. No.: 201,910
[ June 26,1973
Primary Examiner-Richard A. Gaudet Assistant Examiner -Lee S Cohen A ttorney Carlton Hill, Donald J. Simpson et a1.
[5 7] ABSTRACT A disposable ground plate electrode for effecting a connection of electromechanical equipment to the body of a patient by surface contact, particularly with the aid of a conductive gel, in which the conductive surface of the ground plate is provided with a series of ridges preferably concentric, which are adapted to engage such a body surface and are of a size and shape insufficient to cause discomfort but sufficient to form retaining means for a conductive gel disposed therein to localize spreading such a gel, resulting from relative movement between such a body surface and the ground plate.
4 Claims, 4 Drawing Figures L I J l GROUNDING PLACE OR ELECTRODE FOR ELECTROMEDICAL EQUIPMENT BACKGROUND OF THE INVENTION Electromedical units commonly employed for various medical and surgical procedures have in the past used stainlesssteel and other metallic plates to effect an adequate ground connection to the patient. More recently disposable type ground plates employing a suitable base member, for example, of light cardboard or the like having a metallic layer or coating on one face thereof, have found favorable acceptance, the electrode being sufficiently inexpensive to enable a single use and disposal, eliminating cleaning operations etc. as formerly required with relatively heavy metal plates. A disposable electrode of this type normally is connected to the electromedical equipment by a conductor lead which is operatively connected to the electrode by suitable manually actuatable clamping means, for example, clips similar to alligator-type electrical clips having oppositely disposed jaws, usually spring biased in closed position, which following manual spreading may be applied to the ground electrode, clamping a portion thereof between the terminal jaws.
The use of a conductive gel for effecting a more efficient conductive connection between the skin surface of the patient and the electrode is being more and more extensive. Where prior types of electrodes have been employed, having a smooth surface adapted to contact the body surface of the patient, some difficulties have been experienced in the use of a conductive gel in that movement of the patient relative to the electrode produces a wiping action tending to wipe off the conductive gel, and it is possible to sufficiently wipe an electrode surface that the desired highly efficient conductive connection is reduced, if not materially impaired.
The present invention is therefore directed to the elimination of this problem whereby the gel is effectively retained in the general area desired and is constantly present in an amount to insure the availability of adequate gel at all times and thereby provides and maintains the desired conductive connection.
SUMMARY OF THE INVENTION The present invention not only-accomplishes the desired results but does so with an extremely simple arrangement which may be readily incorporated in ground electrodes directly interchangeable with those heretofore employed.
Such results are achieved in a disposable type electrode by providing the conductive face thereof with a plurality of outwardly disposed ridges or projections which are so sized and proportioned that while insufficient to cause discomfort to a patient using the same, they will achieve a firmer contact with the skin surface and will form retaining means for localizing spreading of conductive gel which might otherwise result from relative movement between the skin surface and the electrode. In a preferred embodiment such ridges may take the form of a series of concentric circles.
The present invention also provides a flap or flange member adjacent at least one edge which may be folded back upon the base portion of the electrode to provide a clamping edge adapted to be received in the jaws of a cooperable clip member with both jaws of the latter effectively engaging the conductive surface of the electrode to provide maximum conductive connection between a mounting clip and the conductive surface of the electrode.
BRIEF DESCRIPTION OF THE DRAWINGS In the drawings wherein like reference characters indicate like or corresponding parts:
FIG. 1 is a top plan view of a ground electrode constructed in accordance with the present invention;
FIG. 2 is an elevational view of a portion of such an electrode illustrating the attachment thereto of a connector clamp or clip of a type commonly employed;
FIG. 3 is a similar side elevational view illustrating the connection thereto of a connector also in a common use at the present time, and
FIG. 4 is a sectional view through a portion of an electrode structure constructed in accordance with the present invention illustrating the gel retaining action resulting therefrom.
DETAILED DESCRIPTION OF APREFERRED FORM OF THE INVENTION Referring to the drawings and more particularly to FIGS. 1 and 2, the reference numeral 1 indicates an electrode structure of sheet-like formation, the embodiment illustrated comprising a base sheet 'or member 2 of inexpensive material, such as lightcardboard or the like, to which is laminated or otherwise applied to the upper surface thereof a relatively thin conductive sheet or layer 3, for. example, a'suitable metallic foil such as an aluminum foil which is suitably applied and secured to the base member or board 2 by any suitable means to form an integral structure having a conductive upper surface.
Disposed on the upper face, i.e., the conductive face of the electrode, are a plurality of upwardly extending projections or ridges 4, illustrated as having a concentric circular configuration with respect to the approximate center of the electrode. The circular ridges 4, as illustrated in FIG. 4 on an enlarged scale, may be readily formed by a suitable embossing of the laminated card stock, with the embossed projections or ridges 4, in the embodiment illustrated, having a flat top surface 5 connected to the adjacent portions of the electrode by diverging surfaces 6 of annular configuration with the side surfaces 6 forming relatively sharp edges at their junctures with top surface 5. The transverse cross sectional proportions of the ridges 4 are preferably such that the elevation of the surface 5 above the general plane of the conductive surface 3 is insufficient to create discomfort on the part of a patient, for example, laying thereon, but at the same time, form side wall surfaces 6 of sufficient height to achieve the desired gel retaining action hereinafter described.
In addition to the ridges 4, the electrode may be provided with score lines or ridges 7 adjacent one or more edges of the electrode, which lines in the embodiment illustrated are quite similar in proportions to the ridges 4 and may function as fold lines along which the elec-' effected by means of a spring clip, indicated generally by the numeral 10, that is illustrated in FIG. 2 being of known construction. The clip 10 illustrated, comprises a pair of spring arms 11 which are supported in a block 12 with the arms 11 being electrically connected with the electrical conductor 9. The arms 11 are provided with a suitable configuration operative to resiliently urge the jaw portions 13 thereof toward one another, exerting clamping forces on an object interposed therebetween such as the edge portion of the electrode 1. FIG. 2 illustrates the clamp 10 as engaging only a single thickness of the electrode sheet and consequently, only one of the jaws 13 makes electrical contact with the conductive surface 3.
Preferably,- the sheet is folded over along one of the fold lines 7 as illustrated in FIG. 3 whereby, the terminal clamp. may engage the conductive coating 3 on opposite faces of the electrode structure. In this construction the known type of clip 10", is provided with two oppositely disposed jaws 13a and 13b, and jaw 13b being urged into clamping relation by a thumb screw 19 with each jaw engaging a respective portion of the conductive coating 3. v
In use, the patient may be disposed upon the ground electrode with the latter disposed at the desired point of contact, normally following the application of a suitable amount of gel to the conductive surface of the plate to insure an efficient electrical connection between the skin surface-of the patient andthe conductive surface of the electrode.
As illustrated in FIG. 4 which represents, on an enlarged scale, a cross sectional view through one of the ridges or projections 4 and contacting portions of a body thereon, it will be'noted that the ridges 4 perform two functions, the first being to depress the skin surface adjacent the top portion 5 of the ridge, thereby providing increased pressure thereat', and second, at the same time, the side walls 6 of the ridges form abutments at which gel may accumulate, this also being facilitated by any slight spacing of the skin surface from the juncture of the side wall with the main bodyof the sheet, forming a small space of more or less triangular cross sections at the juncture of the side wall 6 with the base portion at which the gel may accumulate. In the event the patient tends to slide or shift on the electrode, the portions of the respective ridges intersecting the line of direction of movement of the patient relative to the electrode will act as gel retaining abutments, each ridge tending more less to squeegee the gel from the skin surface during such relative movement and thereby prevent a major displacement of the. gel on the sheet or possibly ever off of the sheet. Consequently, an adequate supply of gel is retained on the electrode at all times, and in particular, at the respective ridges.
It will also be appreciated that in addition to their function with respect to the conductive connection, the ridges also serve the additional function of providing a relatively nonskid effect whereby improved resistance to movement between the patient and electrode is achieved.
While the size and proportions of the electrode may vary in dependence upon specific requirements with respect to size of the patient and location at which the electrode is to be disposed, I have found that very good results can be obtained utilizing a sheet having overall dimensions of 10" X 13" which may be provided with the fold lines 7 disposed 1 inch from the adjacent end particular pattern gives a symmetrical arrangement relative to the center of the electrode and provides an ad equate number of ridges to insure effective desired retention of the gel on the electrode structure.
As the electrode is made from relatively light cardboard or the like, and a very thin lamination of conductive material, in the event a smaller electrode is desired, the sheet may readily be cut with ordinary scissors to the desired size and configuration, with the respective ridges then providing guide means for such cutting operations whereby, symmetry, if desired, may be readily achieved with a minimum of effort.
Having thus described my invention it will be apparent that the present invention provides a substantially universal ground plate which may be used with substantially any time any connector terminal employing a clamping action, whether by spring, screw, or otherwise. Likewise, where the terminal is so constructed that it will engage both conductive faces when the edge portion of the electrode is folded over as illustrated in FIG. 3, the electrode preferably is so folded. However, if the terminal connector will not effect such a double contacting, the electrode may be utilized in its unfolded state with the terminal means being attached in a manner comparable to that illustrated in FIG. 2.
Having thus described my invention it will be obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention.
1. A disposable ground plate electrode for effecting a connection of electromedical equipment to the body of a patient by surface contact usually by resting thereupon, particularly with the aid of a conductive gel, comprising a normally planar base member of suitable sheet stock having a top face formed by a conductive layer carried thereby, said conductive layer having a plurality of outwardly extending relatively narrow elongated ridges formed thereon in a symmetrical pattern and covering a major portion of said top face and adapted to engage the skin surface of such a body, said ridges projecting beyond the surface of such conductive layer a distance sufficient to form a plurality of collection abutments for a conductive gel disposed on such sheet, the abutments being angled inwardly with respect to the central portion of the electrode, whereby outward spreading of such gel on said sheet as a result of relative movement between such sheet and the skin surface of such a body is localized and thereby retained on such sheet.
2. A disposable ground electrode according to claim 1, wherein said pattern comprises a plurality of concentric circles.
3. A disposable ground plate electrode according to claim 2, wherein said base member is provided with a fold line adjacent at least one edge thereof, defining a 3 ,741 ,2 l 9 5 6 peripheral strip which may be folded back upon the such surface. base member with the conductive face of the strip out- 222332;;2 32f; zg z ggzz gg fiig g giggl claim 3, wherein said sheet is provided with respective mem with opposed portions of clamping means carried 5 fold lines adjacent oppositely disposed edges thereof. by a conductor lead to be electrically connected to 4. A disposable ground plate electrode according to