WO1990001224A1

WO1990001224A1 - Universal clasp for external electro-medical electrodes

Info

Publication number: WO1990001224A1
Application number: PCT/US1988/002428
Authority: WO
Inventors: James R. Leblanc
Original assignee: The Leblanc Corporation
Priority date: 1988-07-18
Filing date: 1988-07-18
Publication date: 1990-02-08

Abstract

A universal clasp for transfer of electro-medical signals between an external electrode on a patient and signal monitoring or generating device. A pair of elongated electrically conductive arms (16, 18) are pivotally articulated with electrical contact surfaces and handle means at longitudinally opposite ends. A unitary spring means (50) held internally between such clip arms (16, 18) biases planar and curvilinear configuration electrical contact surfaces (34, 40) together and, also, presents electrical receptacle means (60) at the longitudinally opposite handle end of the clasp, for receiving and securely holding, under spring tension, a pin type connector (70). External surfaces and side edges of the metallic clip arms are electrically insulated by shielding means (30, 32) of configuration which interfits with the clip arms (16, 18) and covers exterior surfaces thereof.

Description

UNIVERSAL CLASP FOR EXTERNAL ELECTRO-MEDICAL ELECTRODES

This invention relates to electrical clasp structure for transferring electro-medical signals. In its more specific aspects, this invention is concerned with a universal clasp for transfer of electro-medical signals such as cardiovascular (CV) signals to electrocardiographic (ECG) equipment or electrical impulses being directed to a patient.

Sensors for ECG readings, referred to as external electrodes, are placed in contact with a patient's skin at selected locations about the torso and limbs. Such external electrodes, which can also be used for electrically imposed nerve or muscle ^' stimulat ing impulses, are adhesively held against the patient and include a conductive gel which reduces electrical resistance to facilitate electrical impulse transfer to or from the body via the electrode.

The present invention enables effective and efficient electrical connection with the various external electrode types and the various sizes of male pin-type cable connectors in general use for transfer¬ ring electro-medical signals.

External electrodes include the planar-tab type and a curvilinear configuration "button" type. For cable connector adaptability, an electrical receptacle structure is provided enabling easy and rapid connec¬ tion, through a unique spring-action member, for the various sizes of pin-type connectors in general use in this art. Secure interconnection with such male member is made without a threaded coupler or other such coupling means which require mechanical movement as in the prior practice. Such spring-action member provides for receiving and securely holding an electric cable pin connector enabling stable and electrically efficient signal transfer between the clasp and electrical equipment without requiring movement of mechanical coupling parts by the user.

The above and other advantages and contributions of the invention are described in more detail in relation to the accompanying drawings, in which:

FIG. 1 is a pre-assembly perspective view of elements of an embodiment of the clasp structure of the present invention; FIG. 2 is a side elevation view, with portions shown in phantom lines, of a clasp structure assembled from the elements shown in FIG. 1;

FIG. 3 is a right side elevation view of the clasp structure of FIG. 2; FIG. 4 is a cross sectional view of the clasp structure of FIG. 2 taken along the line 4-4;

FIG. 5 is a cross sectional view of the clasp structure of FIG. 2 taken along the line 5-5;

FIG 6 is a perspective view of the receptacle portion of the clasp structure of FIG. 2 in juxtaposi¬ tion with a male connector member, and

FIG. 7 is a schematic arrangement for illustrat¬ ing continuation of interconnection, partially illustrated in FIG. 6, between a clasp structure of the invention and electrical equipment for monitoring or generating electrical signals;

FIG. 8 is a perspective view of one of the encasement elements shown from another angle than that shown in FIG. 1; FIG. 9 is a perspective view of one of the metallic clip elements shown from another angle than that shown in FIG. 1, and

FIGS. 10 and 11 are illustrations, respectively, of planar and "button" type external electrodes for describing functions of the present invention.

The problems associated with attempting to have differing clasp types available for matching with differing types of external electrodes and, for matching with the differing sizes (e.g. 2, 3 and 4 mm diameter) pins provided by cable-connector manufac- turers can cause detrimental delays and have other disadvantageous results. Present teachings provide a universal clasp structure capable of being used with the differing types of external electrodes in general use and providing a secure and electrically efficient receptacle which accommodates the various size pin connectors in general use for transferring electro- medical signals. In brief, such clasp structure is "universal" at its longitudinal end which is connected to an external electrode and at its longitudinally opposite handle end which is connected via a cable to electrical equipment for receiving or generating electro-medical signals.

A unique-configuration, unitary spring member is assembled between metallic clip arm elements, as shown in FIGS. 1 and 2, to provide, among other functions, for rapid and easy reception of such variety of pin connectors. Such pair of electrically-conductive clip arms are pivotally articulated, about a rivet-type axle, and positioned by the unitary spring which also provides for biasing of the clip arms.

The means for making electrical contact with external electrodes are located at the working end 14

(FIG. 2) of elongated clip arms 15 and 18. As illustrated in FIGS. 1 and 2, clip arm 16 is the "upper" clip arm and clip arm 18 is the "lower" clip arm. Each clip arm is electrically conductive through¬ out its length. Interconnecting rivet 20 is located, as shown, intermediate the working ends and handle ends of the clip arms; rivet 20 is secured in place after assembly; the clip arms, as shielded by asso¬ ciated insulation elements, pivot about axle portion 21 of rivet 20.

Each electrically-conductive clip arm (16, 18) includes an elongated nose portion (22, 24, respec¬ tively) for connection with a planar tab type of electrode, shown and described later herein. A serrated contact surface, as seen at 26 of arm 18, is provided for improving the contact and stability of contact with planar tabs. Serrations on contact surfaces for each clip arm can be aligned to provide for mating of opposed serrated surfaces to improve the grip on a planar tab.

Curvilinear-configuration electrical contact means are positioned longitudinally intermediate nose 14 and the location for rivet 20. Such curvilinear contact means are defined by concave openings located along the side walls of the electrically conductive clip arms and electrically insulating shields for exterior surfaces and edges of such clip arms. Referring to FIG. 1, a matching-contour, electri¬ cally-insulating cover is provided for the exterior surface and edges of each electrically-conductive clip arm so as to prevent extraneous signals entering the system or interference with signals being transferred. Shield 30 covers the external surface and edges of electrically-conductive clip arm 16; and, shield 32 similarly covers clip arm 18. Such shield members are interfitted and interlocked with the clip arms as described later herein. Each of the electrical- insulating shields has a configuration to provide ready access for electrical contact with a planar tab contact or a curvilinear contact external electrode at the working (electrode contact) longitudinal end of the clasp structure. Shield 32, for lower clip arm 18, is likely to be the shield which is next adjacent to a patient's skin.

As shown in FIGS. 1 and 2, the side elevation contours at the electrode contact end of each clip arm serve the same function. That is, the planar exten¬ sions which provide for connection to a planar tab have essentially the same configuration, with serra¬ tions on confronting surfaces; and the curvilinear contact portions are mirror images of each other for connection to a button electrode. Also, the contours of the insulating covers follow those of the clip arms at such working ends. For example, the contour of the curvilinear contact 34 of clip arm 16 is the same as the curvilinear contour 36 of shield 30. This feature is also illustrated by FIG. 2. The clip arm edge protection provided by the cover shields is illus¬ trated by the transverse cross-sectional views of FIGS. 3, 4 and 5; the sidewalls of the shield prevent contact with side edges of the clip arms while not in any way inhibiting electrical contact by the electrode contact surfaces on the interior of each clip arm.

The confronting, spaced-apart , curvilinear surfaces 34, 40 of the clip arms 16, 18 provide optimum electrical contact for the curvilinear periphery of the "button type" of external electrode illustrated later herein. Sidewall contour 41 of shield 32 has the same configuration as contact surface 40 of clip arm 18.

The planar and curvilinear configuration elec- trode contact means are contiguous to the working end 14 of clasp 44. The clip arms are biased so that the contact means are in confronting relationship (with planar tab contact surfaces contacting in FIG. 2) by spring action. Clip arms 16, 18 are articulated about shaft 21 of rivet 20. Spring means 50 (FIG. 1) includes (upper) spring arm 52 in contact with the inner surface of clip arm 16; and, spring arm 54, major portions of which are in contact with, or against an inner sidewall surface (such as 55) of clip arm 18.

An important additional contribution of spring structure 50 is providing an electrical receptacle for rapid and easy electrical interconnection through a connector pin on a cable extending to an electrical apparatus. Stable and secure reception of a connector pin, as provided by spring structure 50, is free of need for any of threaded or Other type of assembly which required a separate mechanical movement by the user for electrical coupling. The connector pin is held securely in place by insertion into spring structure 50.

Referring to FIG. 1, spring 50 is unitary. In a preferred embodiment, it is preferably formed from flat sheet metal; then the sheet metal treated to provide desired spring-action temper. Spring arm 54 includes longitudinally-extending side flanges (such as 57 in FIG. 1) which contact inner sidewall surfaces of clip arm 18. From such side flanges, the metal of the spring arm extends, as shown, downwardly and inwardly in a transverse direction to help to define an intermediate groove 58 which extends longitudinally of the clasp structure. The curvilinear (substan¬ tially circular) opening 60 (see also FIG. 3) is defined by spring 50 as it curves in an arc 62 toward tongue portion 64; the latter extends longitudinally in the clasp structure, and downwardly toward and into groove 58 formed by the unitary metal of spring structure 50.

This spring structure establishes a unitary, open, electrical-coupling receptacle. Such an opening is defined at the handle end of clasp structure 44 for receiving a connector pin so as to be received and held firmly, by spring action, to provide for effi¬ cient electrical transfer of electro-medical signals. The arch shaped configuration 66 of cover element 32 shields the electrical receptacle structure from electrical contact with a patient or other extraneous interference; it also lends stability and strength to the overall structure; also it helps, in combination with a portion of cover element 30, to prevent lead wires or connector cables from entering under end 68 of cover 30 when clasp structures and connector cables are being readied or stored out of use.

Pin member 70 (FIGS. 6 and 7) is in electrical contact with cable 72 and extends beyond the usual plastic coupling sleeve 74. Pin 70 is inserted through opening 60 and is held under spring tension against groove 58 by the longitudinallyl-extending tongue portion 64 of spring structure 50. The insulating arch 66 electrically shields such cable end portions. The cable 72 extends to electri¬ cal equipment 76 (FIG. 7) which is used for measuring or generating impulses.

As indicated by the phantom lines of FIG. 2 and the cross-sectional views of FIGS. 3 4 and 5, external surfaces and edges of the electrically-conductive clip arms 16 , 18 are covered by contour-conforming, electrical-insulating shields 30, 32. Interacting fastening means are provided between the clip arms and the shield elements. Studs 78, 80 (FIG. 8) which are unitary with shield 30 interfit with openings 82, 84 of electrically conductive clip arm 16; stud 86 which is unitary with shield 32 interfits within opening 92 of electrically conductive clip arm 13 (each opening can have the shape of a slot) for receiving and interlocking with members of adjacent insulating covers.

Electrical shielding cover means 30, 32 are fabricated from a heat-stable, electrically-insulat- ing, plastic material, such as polymethylpentene ( "TPX" ) , and are affixed snugly and quickly to the clip arm surfaces by such interfitting studs (with rivet-type heads) within such circular openings* and movement along the key slots of the clip arms. The unique configurational and physical aspects of the unitary spring 50 perform the biasing function, which holds the electrode contact surfaces together (unless opened by the handle means) and, perform the electrical coupling function (for the pin connector) at the opposite longitudinal end of the clasp struc¬ ture. A major portion, at least about 90%, if not substantially all, of the pins used for electro- medical signal transfer can be accommodated by the spring structure dimensions taught herein. Pins (of two, three or four millimeter diameter) can be utilized and the gripping force provided by the specific embodiment shown and described is substan¬ tially in excess of that required by the adhesive properties of the external electrode. Also the electrical contact force at the opposite longitudinal end of the clasp structure exceeds that required. in both instances the clamping force must be strong enough that if sudden movement by a patient, or accidental pulling on a connector cable occurred, the clamping force at both ends of the clasp structure should be in excess of the adhesive strength with which the external electrode is held to the patient's body.

With certain cable structures, primarily for 2 mm pins, sleeve 74 can be of a shape and size to fit snugly within opening 62 so as to provide additional holding force over and above that established by the spring action of tongue portion 64 holding pin 70 against the surface(s) of groove 58. During assembly, guide markings 97, 98, which can take the form of apertures in the spring structure, are used to locate spring 50 on corresponding protru¬ sions 94, 96 along metal clip arm 18 (FIG. 1). Spring 50 is then spot welded in place to clip arm 18. During assembly, clip arm 16 compresses spring arm 52 sufficiently so that rivet 20 can be fitted into aligned openings (such as 100, 102, 104 as visible in FIG. 1) of the clip arms. The inserted distal end of axle portion 21 of rivet 20 is then swaged sufficient- ly to hold the rivet in place. The shield members 30, 32 are then positioned on the clip arms.

Approximate dimensions for a elements of the illustrated embodiment are as follows: Length Width Working End Handle End

Shield 30 1.290" 0.205" 0.0370" Shield 32 1.525" 0.195" 0.360" Clip Arm 16 1.235" 0.150" 0.300" Clip Arm 18 1.500" 0.150" 0.300"

Spring Structure 50

Overall length (in place) 0.940"

Length of Arm 52 0.530" Length of Tongue 64 0.200"

Diameter of Opening 60 0.160" Rivet 20 •

Length 0.280"

Diameter of Shaft 21 0.060" In practice, the clip arms can be fabricated from low carbon flat-rolled steel (nominal thickness about 0.020") with the entire structure coated by medical- grade plating practice with nickel so that no portion of the clasp is subject to rusting. Rivet 40 is preferably stainless steel and spring 50 is spring steel.

The electrical-insulating shields 30, 32 when made from polymethyl pentene, "TDX", have a thickness of about 0.020"; the interfitting studs have a diameter of^* about 0.065", the sidewall height of end 68 is about 0.145", and the overall height of arch 66 is about 0.370".

While specific configu.rational aspects have been shown and dimensional data as well as material characteristics set forth to enable those skilled in the art to make and use the invention, it is under¬ stood that modifications can be made to the specifics described while relying on the above teachings; therefore, for purposes of determining the scope of the present invention, reference shall be had to the appended claims.

Claims

CLAIMS 1. Universal clasp structure capable of being releasably connected to either a planar tab-type or a curvilinear-surface button-type external electrode and being adaptable for use with pin-type connectors of a variety of sizes to provide electrical coupling for transfer of electro-medical signals between external electrode contact with a patient and electrical equipment for monitoring or generating such signals, comprising: a pair of elongated electrically conductive clip arms, each clip arm having electrical contact means contiguous to one of its longitudinal ends, and handle means at its remaining longitudinal end; mechanical means pivotally interconnecting said pair of clip arms intermediate their longitudinal ends in articulated relationship, with said electrical contact means at said one longitudinal end of each clip arm confronting each other, and said handle means at the remaining longi- tudinal end of each said clip arm being disposed for articulated movement toward each other about said mechanical interconnecting means so as to open said confronting contact means, said electrical contact means on each said clip arm including: a planar surface contact, and a curvilinear configuration contact, said planar surface contact extending from the distal end of each said clip arm toward said mechani- cal interconnecting pivot means for said arms and presenting an elongated nose portion of substantially flat configuration in longitudinal cross section, said curvilinear contact of each clip arm being located intermediate said planar surface contact and said interconnecting means; and elongated unitary, electrically-conductive, spring means, formed from flat sheet metal, coacting between such pair of electrically-conductive clip arms, such spring means including a pair of articulated spring arms acting on said clip arms as pivotally interconnected to bias said confronting electrical contact means of said clip arms together, one each of such pair of spring arms contacting a separate single clip arm, and with one of such spring arms forming electrical coupling receptacle means, located at the handle end of the clasp structure, for receiving and securing an electrically conductive pin member for transfer of electro- medical signals. 2. The structure of Claim 1 further including: an electrical insulation cover means shielding external peripheral surfaces of said electrically conductive clip arms between said longitudinal ends of each clip arm to electrically insulate said clip arms from electrical signals other than through said confronting contact means at said one longitudinal end of each said clip arm. 3. The structure of claim 1 in which said planar contact surface of each clip arm has a width dimension of about 0.15" and a length dimension of about 0.2", and in which a lateral sidewall leg of each said clip arm presents such curvilinear-configuration contact located intermediate such planar contact surface and the location for pivotally interconnecting said arms. 4. The structure of Claim 1 in which the electrical coupling means located at such handle end of at least one of said clip arms as 13 defined by one of such spring arms includes an opening in such one spring arm in a plane which is transverse to the longitudinal direction of such clip arms, and a groove portion in such spring arm which extends longitudinally of such clip arm, said opening receiving and directing a pin-type connector toward said groove to establish electrical conduction between such connector and such clip arms through such spring means. 5. The structure of claim 4 in which such electrical coupling means as defined by one of such spring arms includes a longitudinally-directed extension which is curved toward suchuchgroove portion from said opening so as to force such pin-type connector inserted into said opening toward said groove. 6. The structure of Claim 4 in which said means for pivotally interconnecting said clip arms com- prises elongated cylindrical configuration rivet means. 7. The structure of claim 6 in which said clip arms have a U-shaped cross-sectional configuration in a plane perpendicularly transverse to the longitudinal axis of each said clip arm, 5 with leg means of said U-shaped configuration6 comprising a leg on each lateral side of said clip7 arms,8 each said lateral leg presenting an aperture,9 which is centrally located between longitudinal ends10 of said clip arms, for receiving said rivet means to11 pivotally interconnect said clip arm.1 8. The structure of claim 6 in which2 such cover means and electrically-conductive clip3 arms include coacting means for securing cover means4 to each said clip arm.

1 . 9. The structure of claim 8 in which such

2 coacting means includes

3 stud means on such cover means which interfit

4 with opening means in such clip arms, and further

5 including

6 means for establishing the location of such

7 spring means longitudinally in relation to such clip '8 arms .

1 10. A clasp structure for electro-medical signal

2 transfer between an external electrode and an electri-

3 cal apparatus, comprising

4 a pair of elongated, elect ically-conductive

5 clip-arms held in articulated relationship by a pivot

6 means interconnecting such clip arms at a location centrally located intermediate longitudinal ends of said clip arms, and spring means, held between such interconnected clip arms so as to bias such clip arms at one of their longitudinal ends toward each other, such spring means defining electrical receptacle means located contiguous to the remaining longitudinal end of such clip arms for receiving and securely holding under spring tension a pin-type electrical connector inserted into such electrical receptacle means.