US 3740703 A
A terminal clip, particularly for connecting a lead conductor to an electrode structure for making electrical connection to human skin surface and the like, especially a disposable type electrode, in which the electrode structure is provided with a button type male terminal, the clip being constructed to engage such a terminal by relative lateral movement of respective terminal clamping portions thereof transverse to the axis of such a button terminal wherein the clip may be attached to or detached from such a button terminal with slight, if any, pressure being applied to the electrode in the direction of the skin surface to which the electrode may be applied.
Description (OCR text may contain errors)
Sessions 1 June 19, 1973 l TERMINAL CLAMP  Inventor: Robert W. Sessions, German Church Road, Hinsdale, Ill.
 Filed: Nov. 24,- 1971  Appl. No.: 201,799
Primary ExaminerJoseph H. McGlynn Attorney-Carlton Hill, Benjamin H. Sherman. Charles F. Meroni et al.
 ABSTRACT A terminal clip, particularly for connecting a lead conductor to an electrode structure for making electrical connection to human skin surface and the like, especially a disposable type electrode, in which the electrode structure is provided with a button type male terminal, the clip being constructed to engage such a terminal by relative lateral movement of respective terminal clamping portions thereof transverse to the axis of such a button terminal wherein the clip may be attached to or detached from such a button terminal with slight, if any, pressure being applied to the electrode in the direction of the skin surface to which the electrode may be applied.
11 Claims, 5 Drawing Figures TERMINAL CLAMP BACKGROUND OF THE DISCLOSURE The present invention is directed to a terminal clip for connecting an electrical conductor of electromedical equipment or the like to an electrode or other structure, particularly for electrodes adapted to be attached to the skin of a patient for effecting an electrical connection between such patient and electro-medical equipment which is responsive to body or skin currents.
Electrodes of the type referred to may employ a structure adapted to be adhesively secured to the skin surface of a patient, such electrode being provided with a terminal, for example a button type male terminal adapted to be snapped into a cooperable female terminal connected to the conductor involved. A portion of such button terminal, or other means conductively associated with the terminal, may be utilized for the electrical connection between the terminal and the skin surface, a suitable conductive gel often being employed for this purpose.
The so-called button or snap-on" type of connecting terminals normally employs a button-type male member having an enlarged head which is adapted to be inserted in the cooperable member, which usually is of a semi-resilient construction having resilient portions engageable with the head of the button and which must be separated, or rather sprung into a position permittinginsertion and engagement with the head of the button member. Such spreading action must be achieved by disposing the two terminals in cooperable position for engagement and applying pressure to force the female terminal on the male terminal.
In the case of an electrode mounted on the skin surface of a patient such applying pressure thus results from the application of pressure on the female terminal in a direction toward the skin surface, thereby also forcing the male terminal toward the skin surface. Depending upon the-force required to effect the mounting engagement of the terminals, obviously the applied pressure will result in a considerable pressure on the terminal of the electrode tending to compress the adjacent flesh of the patient until the firmness thereof is greater than the pressure forces required to effect engagement of the two terminals. It is believed apparent that where an electrode structure is constructed for ad hesive mounting on the skin surface of the patient with a conductive gel forming the conductive connection between the electrode terminal and the'skin surface, the necessary pressure required to effect connection of the terminals results in a considerable pressure on such conductive gel, tending to spread such gel outwardly with two disadvantageous'results. First, such pressure results in a severe spreading of the gel radially outward in all directions from the central terminal which, in many instances, is sufficient to effect a separation of the adhesively connected portions of the electrode from the skin surface, thereby considerably reducing the effective attaching area and which, in some cases, could even result in a sufficient weakening of the adhesive bond between the electrode and the skin surface to a point where electrical conduction is impaired by the poor connection of the electrode structure to the skin surface. At the same time, the forcing of the conductive gel outwardly away from the central portion of the electrode containing the terminal structure, removes the conductive gel from the specific spot in which it was to do its work, namely between the inner face of the electrode terminal structure and the opposing skin surface, thus further reducing the efficiency'of the conductive connection following release of the applied pressure.
The present invention therefor is directed to the problem of eliminating the undesired displacement of the conductive gel by eliminating the necessity of applying pressure at any time to the terminal of the electrode structure.
BRIEF DESCRIPTION OF THE INVENTION The problem of the invention is solved by the production of a terminal clip by means of which a conductor may be operatively connected to an electrode of the type described without the application of undesired pressure on the terminal in a direction towards the skin surface i.e., by providing a structure in which the applying forces are laterally directed to portions of the terminal clip with substantially no force whatsoever being applied in a direction toward the electrode structure or the terminal thereof.
These results are achieved in the present invention by an arrangement in which a pair of members are pivotally connected for limited movement about an axis substantially normal to the skin surface to which such an electrode is supplied, such members having superimposed portions, each of which are provided with an opening therein of a size to receive the head of the button terminal of such an electrode with such members being pivotal from a position in which such openings are in alignment to a position in which such openings are out of alignment, spring means being provided to resiliently urge the members in nonaligning positions. Thus by manually effecting relative movement of the members in opposition to such resilient means the members may be moved to a position bringing the openings into sufficient alignment that the terminal of the electrode may be received therein whereby upon release of the members the resilient means will urge the members into a position in which the button terminal of the electrode structure is firmly clamped between oppositely disposed portions of the two members.
The electrical conductor may be either directly connected to the terminal clip by soldering or otherwise, or the clip may be provided at a suitable location with an auxiliary button terminal corresponding to that of the electrode, which auxiliary terminal thus may be engaged with a cooperable terminal on the electrical conductor, normally directly engageablewith the electrode terminal. In use of such structure the terminal of the conductor is' engaged with the terminal of the clip to securely fasten the two together and the clip then utilized to make the final'connection to the electrode structure. As the force required to move the two members into a position, for operative engagement with the terminal of the electrode, is exerted in a direction parallel to the skin surface and not transverse thereto engagement with the terminal of the electrode may be readily effected with substantially no pressure being applied on the electrode structure in a direction towards the patients skin, thus substantially eliminating any tendency to spread conductive gel disposed between the electrode structure and the skin surface.
The present invention thus not only provides a novel terminal which may be substituted for terminals normally mounted on'electrical conductors of the type herein referred to, but also enables the utilization of the present invention with existing terminal structures both on the electrode and on the cooperable conductors, merely by interposing the terminal clip of the invention between the respective terminals now employed.
BRIEF DESCRIPTION OF THE DRAWING In the drawings wherein like reference numerals indicate like or corresponding parts:
FIG. 1 is a top plan view of an electrode structure illustrating the mounting thereon of a terminal clip constructed in accordance with the present invention;
FIG. 2 is an enlarged view, similar to'FIG. 1 of merely the terminal clip, illustrating positions of the parts thereof when detached;
FIG. 3 is a sectional view taken approximately on the lines IIIIII of FIG. 1;
FIG. 4 is a sectional view taken approximately on the lines IV-IV of FIG. 1; and
FIG. 5 is a side elevational view of a terminal clip constructed in accordance with the present invention illustrating a direct connection of a conductor thereto.
DETAILED DESCRIPTION OF THE INVENTION Referring to FIGSQl and 4, the reference numeral 1 indicates generally an electrode structure of the type to which the present invention is especially applicable, such electrode structure comprising, for example, a disc shaped base member 2 of suitable sheet material having an adhesive coating 3 on the bottom face thereof as viewed in FIG. 4 which is shown as being covered by a protective cover sheet 4 adapted to be stripped off prior to usage to expose the adhesive coating 3. The disc 2 is provided with a central opening 5 therein which is covered by a smaller disc 6, likewise of suitable sheet material which is suitably secured thereto by means of an adhesive or the like. Secured to the disc 6 is an electrical terminal structure indicated generally by the numeral 7 which, for example, may be constructed in two pieces 8 and 9, the piece 8, for example, having a disc'like base portion 10 from which extends a hollow button terminal 11 the outer end of which has an enlarged head portion 12. The piece 9 likewise may be of disc like configuration and provided with a suitable projection or shank 13 which extends through the sheet 6 into the terminal 1 1 and rigidly secured thereto, thereby clamping the sheet 6 firmly between the pieces 8 and 9. The terminal 7 is of commonly used construction and many units of electrical or electronic medical equipment utilize conductor leads, or the like, having terminals adapted to be snapped on the on the terminal structure 7. As the details of construction of such a conductor terminal form no part of the present invention such a terminal, it is illustrated in FIG. 3, merely in elevation and designated by the reference numeral 14 from which an electrical conductor 15 extends.
As illustrated in FIG. 4 the'electrode 1 is provided at the terminal piece 9 with a circular pad 16 adapted to hold a quantity of conductive gel, either applied to the pad immediately prior to usage to prepackaged with the electrode with the gel thus adapted to make conductive connection between the terminal member 9 and the skin surface ofa patient to which the electrode structure 1 is applied. It will be appreciated that if the electrode structure of FIG. 4 were to be connected to the conductor 15 in the usual manner by a cooperable terminal member 14 such connection would have to be effected by disposing the terminal member 14 directly above the terminal 7 and sufficient downward pressure applied to the terminal 14 to snap it on the terminal 7.
The reference numeral 17 indicates generally a terminal clip constructed in accordance with the invention, the clip being illustrated in FIGS. 1, 3 and 4 as applied to an electrode structure 1, no connectingv conductor or terminal, however, being illustrated in FIG. 1. The terminal clip 17 comprises a pair of members 18 and 19 illustrated as being formed from suitable sheet metal stock and fonned to provide respective base plates or portions 20 and 21, pivoted together by a stud member 22, illustrated as having a shank 23 extending outwardly from the two base plates. Extending along an outer edge of the plate 20 is an outwardly or upwardly extending sidewall 0r flange 24, and in like manner extending along an edge of the plate 21 is a similarly extending flange or sidewall 25.
Extending around the shank 23 of the stud 22 is the central portion 26 ofa torsion spring indicated generally by the numeral 26 having like oppositely disposed portions 27 and 28 adapted to bear respectively on the flanges '24 and 25 of the respective plates thereby tending to urge the plate 18 in a clockwise direction and the plate 19 in counter clockwise direction with respect to the axis of the stud 22, producing correspondingseparating movement of thewalls 24 and 25. As illustrated in FIG. 2, the base plate 20 is provided with a circular opening 29 therein and the base plate 21 with a similarly shaped opening 30 therein, the opening 30 being slightly smaller than the opening 20 but of a size to permit passage therethrough of the head 12 of the terminal 7. As particularly illustrated in FIGS. 2 and 4, a portion of the base plate 21 defining the periphery of the opening 30 is deformed downwardly into the opening 29, forming a projection 31, the lower edge of which is defined by the adjacent peripheral edge of the opening 30 as illustrated in FIG. 2. When the clip is unconnected, the legs 27 and 28 of the torsion spring tend to effect relative rotation between the two base plates 20 and 21, in a direction to move the respective elements to positions such as that illustrated in FIG. 2 with the pivotal movement under the action of the torsion spring continuing until the members reach relative positions such as illustrated in FIG. 2, in which the outermost end edge 32 of the projection 31 forms an abutment engageable with the adjacent peripheral edge of the opening 29, thus functioning as a stop to control the separating movement of the respective members.
The construction illustrated in FIGS. 1, 2 and 3 is adapted to be used as a transition clip for use with exist ing electrodes employing a button terminal of the type illustrated to which a terminal 14 of a lead conductor 15 is adapted to be connected, in the manner previously described, by exerting downward forces on the terminal 14 to snap it into locking engagement on the button terminal 7 of the electrode. To this end, one of the members 18 or 19, in the embodiment illustrated the member 18, is provided with a mounting or connecting lug 33, illustrated as an extension of the base plate 21, which is provided at the same side thereof as the shank 22 with a button terminal 7' substantially identical to the button terminal 7 of the electrode 1.
Thus, in use, the electrode structure 1, with the pad 16 containing an appropriate quantity of conductive gel, may be suitably mounted on the skin surface of the user, without applying downward pressure upon the central portion of the structure containing the terminal 7 and pad 16, where the mounting operation will not tend to unduly spread the conductive gel along the skin surface of the user beneath the sheet 2. The terminal 14 of the lead conductor 15 may then be snapped upon the corresponding button terminal 7, substantially as illustrated in FIG. 3, to effectively conductively connect the terminal clip 17 with the electrical conductor 15.
The clip may then be taken between the thumb andforefinger grasping the same by the upwardly extending wall portions 24 and 25 and by this application of a squeezing pressure thereto, the members 18 and 19 may be pivoted in opposition to the action of the torsion spring, into a position in which the opening 30 is sufficiently aligned with the opening 29 to permit reception of the button terminal 7 through both openings to a position substantially as illustrated in FIGS. 3 and 4. As clearly illustrated in FIG. 4, one peripheral edge defining the opening is engaged with the neck portion of the button terminal disposed below the head 12 while the arcuate peripheral edge of the projection 31 engages such neck portion of the button 7 substantially diametrically opposite to the engagement of the peripheral edge of the opening with the button terminal,
whereby clamping forces are exerted by the respective members of the clip upon such button terminal. An effective conductive connection connection therebetween is thereby provided firmly mounting the clip upon the button terminal. Withdrawal movement of the clip from the button terminal is prevented by the enlarged head 12, in the absence of the application of sufficient squeezing forces on the two wall portions 24 and 25. It will be particularly noted that in attaching the clip to the button electrode 7, interlocking engagement therebetween maybe readily effected without applying any downward force to the button 7, all forces attendant to mounting and securement of the clip to the button terminal taking place transversely to the axis of the buttonterminal. Consequently, the conductive gel remains in its most effective position and at the same time the largest possiblearea of the adhesive of the sheet-2 is maintained in contact with the skin surface of the user to insure a very efficient connection between the electrode and the skin surface.
Where the clip is to be supplied as original equipment on lead conductors, such as the conductor 15, the lug 33 merely may be provided with an opening 34 therein through which the extreme end of the lead conductor 15 may be threaded and attached thereto by solder or other suitable means, as for example a swedged connection or the like as commonly employed in the electrical field. The entire portion of the lug 33 associated with the conductor 15 may be suitably protected by an insulating'tube or shell 35, for example, of heat reactive type which may be shrunk down upon the structure to provide a very efficient protective and insulating sleeve.
In all other respects, the clip illustrated in FIG. 5 may correspond to that heretofor described.
It will be appreciated from the above description that I have provided a terminal clip which may be readily employed with present equipment now in use, without change, to eliminate the disadvantages of the previously employed snap-type terminals, whereby substantially no disturbance of the electrode structure, subsequent to mounting on the skin surface, will take place when the lead conductor is attached to the electrode.
At the same time the present terminal clip is exceedingly simple in construction, employing only three movable pieces, including the torsion spring, enabling its manufacture at a minimum of expense.
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 inven tion.
1. A terminal clip, particularly for use on electrodes having a button type male terminal, comprising a pair of members having superimposed portions, each of which has an opening therein of a size to receive such a button terminal, means for pivotally connecting said members for relative pivotal movements, in one position of which the openings are substantially aligned to permit reception of such a button terminal therethrough, spring means operatively connecting said members to apply baising forces thereon urging said members out of said one portion to dispose said openings in non-alignment, cooperable means on said members for facilitating manual movement of said members to said open position in opposition to said biasing means, a projection means on one of said members forming an abutment engageable with the other member for limiting relativeseparating movement of said members, and means on one of said members for operatively attaching a lead conductor to said clip.
I 2. A terminal clip according to claim 1, wherein said abutment on the one member is constructed to extend into and engage the edge of the opening of the other member to limit pivotal movement of said members.
3. A terminal clip particularly for use on electrodes having a button type male terminal, comprising a pair of members having superimposed portions, each of which has an opening therein of a size to receive such a button terminal, means for pivotally connecting said members for relative pivotal movement, in one position of which the openings are substantially aligned to permit reception of such a button terminal therethrough, spring means operatively connecting said members to apply biasing forces thereon urging said members out of said one portion to dispose said openings in nonalignment, cooperable means on said members for facilitating manual movement of said members to said open position in opposition to said biasing means, one of said members being provided with a projection extending into the opening of the other member and adapted to engage an inserted button terminal, cooperable with the other member of clamp such a terminal therebetween, and means on one of said members for operatively attaching alead conductor to said clip.
4. A terminal clip accordingto claim 3, wherein said projection is constructed to form an abutment extending into the opening of and engageable with the other member to limit relative pivotal movement of said members.
5. A terminal clip according to claim 4, wherein said projection comprises a downwardly offset portion of the upper base portion forming a part of the periphery of the opening therein, an edge of such projection forming said abutment.
6. A terminal clip according to claim 1, wherein said members are formed from sheet-metal stock, each member having a flat base portion in which the associated opening is disposed, said base portions being disposed in overlying relation, one upon the other with said pivotal means connecting said base portions for pivotal movement about an axis spaced from said openings and extending normal to the general plane of said base plates, and a pair of outwardly extending manually engageable portions, each carried by a respective base portion along one said edge thereof with one of such outwardly extending portions laterally disposed at one side edge thereof and the other disposed at the laterally opposite side edge of the other of said base portions,
'said biasing means being operative to urge said base portions in directions tending to separate said outmember, said biasing means comprising a torsion spring having a central c'oil portion encircling said shank member and'two leg portions, each bearing on a respective manually engageable portion.
8. A terminal clip according to claim 7, wherein said projection comprises a downwardly offset portion of the upper base portion forming a part of the periphery of the opening therein, an edge of such projection I forming said abutment.
9. A terminal clip according to claim 8, wherein one of said base portions has an elongated extension to which such a lead conductor may be operatively connected.
10. A terminal clip according to claim 9, wherein said extension is constructed to receive a wire forming such conductor for direct attachment to such extension.
11. A terminal clip according to claim 9, wherein said extension is provided with a button terminal corresponding to the terminal of such an electrode, wherein a female connector terminal on such a conductor, normally engageable directly with the male button terminal of such an electrode may be mounted on said terminal of the clip and the latter engaged with the terminal of such an electrode.