Abstract:
An apparatus and method to connect to an electrode is claimed. The apparatus includes a first mating member and a second mating member having first and second openings. A resilient body portion connects the first and second mating members.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 119 of prior filed, co-pending provisional application No. 60/119,677 filed Feb. 11, 1999, and hereby incorporates that disclosure by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to an apparatus that can be connected to an electrode on a patient, and a method of connecting a device to an electrode on a patient. More particularly, the invention relates to an apparatus and method for providing an electrode connector having a low profile and low contact resistance. 
     Electrical treatment and diagnostic techniques are well established in the medical field. For example, it has become well recognized that electrical impulses can be employed for desired medical therapeutic and physical rehabilitative purposes. Further, critical care monitoring of infants and other patients requiring constant care frequently involve electrode based monitoring of electrophysiological signals. 
     Numerous electrode configurations have been described in the prior art. Typical configurations frequently encountered in acute care of premature infants include use of a garment-type snap, or use of a grabber, which operates like a clothespin. A problem encountered with using garment-type snaps is that snaps tend to disconnect easily. A problem encountered with grabbers is that grabbers do not have a low profile, a feature particularly desirable in dealing with infants. Further, traditional snaps and grabbers often have high contact resistance, leading to poor electrical conductivity. 
     SUMMARY OF THE INVENTION 
     Accordingly, the invention provides an apparatus and method to provide a reliable, low profile connection to patient electrodes. The invention allows an apparatus to be connected to an electrode attached to a patient. The apparatus has first and second mating members shaped to form first and second openings. The first and second mating members lie on planes substantially parallel to one another. The apparatus also includes a body portion connecting the first and second mating members. The body portion is integrally formed with the first and second mating members, and has a low profile allowing the connector to be particularly desirable for neonatal patients. When the body portion is compressed, the first and second openings are substantially aligned. The body portion may further include an opening allowing a lead wire to be electrically connected to the body portion. 
     It is an advantage of the invention to provide a method and apparatus to provide reliable electrical and mechanical connections to electrodes. 
     It is another advantage of the invention to provide a method and apparatus of providing a low profile connection to electrodes. 
     It is another advantage of the invention to provide a connector for electrodes having low contact resistance. 
     It is another advantage of the invention to provide a connector for electrodes that is lightweight. 
     It is another advantage of the invention to provide a method and apparatus for providing a connector to electrodes having a large contact surface. 
     Other features and advantages of the invention are set forth in the following drawings, detailed description and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the connector device embodying the invention. 
     FIG. 2 is a perspective view of the connector device in a relaxed position and adjacent a mating stud attached to an electrode on a patient. 
     FIG. 3 shows a top view of the connector device in a compressed position adjacent the mating electrode. 
     FIG. 5A is a section view of a connector device. 
     FIG. 5B is a side view of the connector device of FIG. 5A along section line B—B. 
     FIG. 6 is a side view of the connector device shown in FIG. 6 along section line C—C. 
     FIG. 7A is an exploded, unassembled view of the connector device and a shell for a connector device. 
     FIG. 7B is a perspective view of the connector device and a shell in an assembled position. 
     FIG. 8A is a chart illustrating the contact resistance of the connector device embodying the invention. 
     FIG. 8B is a chart illustrating the contact resistance of prior art electrode connectors. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also it is to be understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. 
     FIG. 1 illustrates a connector device  10  embodying the invention, or more particularly, a raw metal connector before being overmolded with a plastic shell  60 , which will be discussed below. The connector device  10  is formed from a single piece of electrically conductive metal. In a preferred embodiment, the metal is nickel-plated stainless steel. 
     The connector device  10  includes a first mating member  14  and a second mating member  18  arcuately shaped to form first and second openings  22  and  26 , respectively. The first and second mating members  14  and  18  are connected by a resilient or flexible body portion  30 , and positioned in substantially parallel planes. In the preferred embodiment, as shown in FIG. 6, the thickness of first and second mating members  14  and  18  is approximately 0.015 inches. 
     The body portion  30  of the device  10  includes first and second side ridged portions  34  and  38  and center portion  40  connecting side ridged portions  34  and  38 . The center portion  40  and side ridged portions  34  and  38  are generally perpendicular to the first and second mating members  14  and  18 . First and second side ridged portions  34  and  38  are arcuately shaped to form first and second side openings  46  and  50 . The body portion  30  also includes a center opening  42 , from which a lead wire may be attached. 
     The body portion  30 , side portions  34  and  38  and the center portion  40  each have a height. In a preferred embodiment, the height of the side portions  34  and  38  is greater than the height of the body portion  30 . This allows a user of the device  10  to easily compress the side portions  34  and  38  together, towards one another. In a preferred embodiment, the height of the body portion  30  is less than about 0.175 inches, and preferably about 0.167 inches, which gives the device  10  a low profile. Minimizing the size of the connector device  10  decreases the total weight of the connector device  10 . In a preferred embodiment, the weight of the connector device  10  is less than about 0.0286 ounces, and preferably about 0.0282 ounces. Minimizing the height profile and weight of the connector device  10  is particularly desirable for neonatal electrodes. 
     In a preferred embodiment, an insulating shell  60  can be molded over the connector device  10  as shown in FIG. 7A and 7B. The shell  60 , preferably a plastic such as polypropylene, is molded onto the connector device  10  such that the electrode wire  62  protrudes through the center opening  42 . In a preferred embodiment, the electrode wire  62  is soldered onto the connector device  10  through the center opening  42 . 
     FIG. 2 shows the device  10 , insulated by the shell  60 . In FIG. 2, the device  10  is proximate, but not attached, to a mating electrode stud  54  that is electrically connected and attached to an electrode  56  on a patient. The electrode stud  54  has a protruding portion  58  integrally formed with the body of the electrode stud  54 . 
     The connector device  10  is shown in the relaxed position in FIG. 2, wherein the first and second mating members  14  and  18  only partially overlap, and the first and second openings  22  and  26  only partially align. The connector device  10  is biased towards the relaxed position. In the relaxed position, the partial alignment of the openings  22  and  26  does not allow the device  10  to be placed over the electrode stud  54 . 
     When the first and second side portions  34  and  38  are compressed together, as shown in FIG. 3, the first and second side mating members  14  and  18  substantially completely overlap, and the first and second openings  22  and  26  are substantially aligned. Approximately 2.3 pounds of force is necessary to position the device in the compressed position. In a preferred embodiment, the distance between the first and second mating members  14  and  18  is approximately 0.003 millimeters when the connector device is in the compressed position. When the openings  22  and  26  are substantially aligned, the device  10  can be positioned over the protruding portion  58  of the electrode stud  54 . Once the device  10  is placed over the electrode stud  54 , and the protruding portion  58  is situated within the openings  22  and  26  the ridged side portions  34  and  38  are released, and the bias forced connector device  10  causes side portions  34  and  38  to move away from one another into the relaxed position. As a result, the first and second mating members  14  and  18 , and the openings  22  and  26  located therein, engage the protruding portion  58  of the electrode stud  54 , thereby attaching the device  10  to the electrode stud  54  as shown in FIG.  4 . 
     When the connector device  10  is attached to the electrode stud  54 , an electrical connection is made such that the patient&#39;s physiological signals may be monitored. A lead wire  62  can be inserted into the center opening  42  of the connector device  10  to transfer electrical signals captured by the electrode via the electrode stud  54  and connector device  10  to a monitor (not shown). In a preferred embodiment, the lead wire  62  is soldered onto the connector device  10  through the center opening  42 . 
     Because the connector device  10  is biased toward the open, relaxed position, pull action is not required to open or remove the connector device  10  from the protruding portion  58  of the electrode stud  54 . Instead, to remove the attached connector device  10 , the ridged side portions  34  and  38  must again be compressed to release the tension created by the engagement of the mating members  14  and  18  with the electrode stud  54  when the device  10  is attached to the electrode stud  54 . 
     FIG. 8A illustrates the contact resistance of the invention. FIG. 9B is a chart illustrating the contact resistance of prior art electrode connectors. As indicated, the contact resistance of the invention is lower than that of prior art connectors. Accordingly, the connector device  10  of the invention maintains better electrical contact than prior art connectors. The contact resistance of the connector of the invention is preferably less than about 0.010 ohms. In a preferred embodiment, the contact resistance is approximately 0.05 ohms. 
     Various other features and advantages of the invention are set forth in the following claims.