Abstract:
A connector includes a connector body having cavities with through-holes disposed therein. Sealing membranes are received in the cavities and serve to protect the connector from the environment. Wire conductors may pierce the sealing membranes, and may be received by the through-holes of the cavities in the connector. In cavities in which wire conductors have been received, each sealing membrane forms a seal around a corresponding wire conductor. The connector body is formed from a first material, and the sealing membranes are formed from a second material, different from the first material.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 61/405,270 filed Oct. 21, 2010, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector. In particular, the present invention relates to an electrical connector having an improved means for sealing the connector from the environment, and a method for forming such a connector. 
     2. Background of the Related Art 
     Turning first to  FIGS. 1-3 , shown therein is a conventional connector  1  for use in harsh environments. Traditional connectors  1  and modules include M38999, M81714, M12883, and M5105 connectors, and the like. The connector  1  is built with a wire sealing grommet  11  made of silicone. The grommet  11  includes cavities  12  having holes  13 , the holes  13  configured to accept wires  14  inserted therethrough. The holes  13  in the grommet  11  have a diameter that is typically less than the diameter of the wires  14  so that, upon insertion of a wire  14  into the connector  1  through a hole  13 , a tight seal is created between the wire  14  and the grommet  11 . As shown in  FIG. 2 , when holes  13  do not have wires  14  inserted therethrough, separate plastic sealing plugs  15  are used to prevent moisture and debris from entering the cavities  12  and potentially damaging the connector  1 . The sealing plugs  15  come in various sizes, which depend on the diameter of the cavities  12 . Installing these sealing plugs  15  is time consuming. The sealing plugs  15  add weight to the connector  1 , which is undesirable. Furthermore, the sealing plugs  15  have a potential to fall out of the connector  1 , making the protection offered by the sealing plugs  15  unreliable.  FIG. 3  is a more detailed view of the grommet  11  having unfilled contact cavities  12 . 
     U.S. Pat. No. 4,629,269 to Kailus, the entirety of which is incorporated herein by reference, describes a connector insert having pockets that are sealed by a membrane, which is molded integral with the insert. Because the membrane described in that patent is integral with the insert, the membrane necessarily must be made of the same material as the insert. However, the material used for the insert may not be optimal for use as a membrane. Similarly, the material that may be optimal for use as a membrane is not necessarily appropriate for use as a connector insert. Consequently, the membrane may shear when a wire or connector is inserted through it, and pieces of the membrane may interfere with the operation of the connector. In addition, the color of the material used for the insert may not be optimal for use as a membrane, and vice versa. 
     Accordingly, there exists a need to provide a lightweight electrical connector for use with a selectable number of wires, and a method of forming the same, in which the connector is protected against potential damage caused by moisture or other harmful substances in the environment, in which the disadvantages associated with the use of sealing plugs is avoided, and in which the types of materials used to form the sealing membranes and other connector components may be optimized depending on the application for which the connector is desired. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an electrical connector in which the number of wires received by the connector is selectable. 
     It is another object of the present invention to provide an electrical connector in which the connector is protected from the environment. 
     It is yet another object of the present invention to provide an electrical connector that overcomes the disadvantages of the use of sealing plugs, including increased connector weight, increased installation time, and unreliable protection. 
     It is yet another object of the present invention to provide an electrical connector in which the type of material used to form the connector body and the type of material used to seal the connector from the environment may be optimized. 
     Those and other objects of the present invention are accomplished, as embodied and fully described herein, by a connector, and a method for comprising the same, the connector comprising: a connector body having a surface, said connector body comprising a first material; at least one cavity formed in the surface of the connector body; and a sealing membrane received in the at least one cavity, said sealing membrane comprising a second material different from the first material. 
     The connector of the present invention may be configured to receive a wire conductor that pierces the sealing membrane, and the sealing membrane may form a seal around the wire conductor without shearing off when pierced by the wire conductor. The sealing membrane may adhere to the cavity, and may be formed separately from the connector body. 
     With those and other objects, advantages, and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the following detailed description of the invention, the appended claims, and the several drawings attached herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a conventional connector. 
         FIG. 2  is a perspective view of a conventional connector having wire conductors and sealing plugs received therein. 
         FIG. 3  is a detailed view of the conventional connector depicted in  FIG. 1 . 
         FIG. 4  is a perspective view of a connector in accordance with the present invention, the connector having cavities with sealing membranes received therein. 
         FIG. 5  is a top plan view of a connector in accordance with the present invention. 
         FIG. 6  is a cross-sectional view of the connector depicted in  FIG. 5 . 
         FIG. 7  is a top plan view of a connector in accordance with the present invention. 
         FIG. 8  is a cross sectional view of a through-hole and a cavity in accordance with the present invention. 
         FIG. 9  is a cross-sectional view of the connector depicted in  FIG. 5 . 
         FIG. 10  is a perspective view of a connector in accordance with the present invention, the connector having cavities with sealing membranes received therein, and wire conductors that pierce the sealing membranes. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in similar manner to accomplish a similar purpose. It is further understood that the invention may be embodied in other forms not specifically shown in the drawings. 
     Turning to  FIG. 4 , shown therein is a connector  10  having a grommet  20  in accordance with the preferred embodiment. The grommet  20  is part of the connector body  21 , and may be formed separately from, or integrally with, the connector body  21 . The grommet  20  has a number of cavities  22  positioned about the surface of the grommet  20 . A central through-hole  24  is positioned at the center of each of the cavities  22 . Each through-hole  24  extends through the grommet  20 . A silicone membrane  30  is received in each of the cavities  22 . 
       FIG. 5  is a top plan view of the grommet  20  showing the cavities  22  and through-holes  24 . The number and position of the cavities  22  shown in  FIG. 5  is exemplary only, and more or fewer cavities  22  may be provided. In the preferred embodiment shown in  FIG. 5 , the cavities  22  are circular. However, in other embodiments, the cavities  22  may have different shapes and sizes. 
       FIG. 6  is a cross-sectional view of the grommet  20  taken along line B-B of  FIG. 5 , before the silicon membrane  30  is inserted into the cavities  22 .  FIG. 7  is a top view of the grommet, showing the cavities  22  and through-holes  24 . 
       FIG. 8  is a cross-sectional view showing a through-hole  24  and a cavity  22 , and  FIG. 9  is a cross-sectional view taken along line A-A of  FIG. 5 . As shown in  FIGS. 6 ,  8 , and  9 , the grommet  20  has a 3-riser seal  23 , which has three small cavities  22 ,  22   a ,  22   b . An electrical wire conductor  25 , as shown in  FIG. 10 , extends through the 3-riser seal  23 , and the 3-riser seal  23  forms a seal around the wire conductor  25 . In the embodiment shown in the figures, the membrane  30  substantially fills the topmost cavity  22 , which is located at the surface of the grommet  20 . Accordingly, the membrane  30  is directly accessible at the surface of the grommet  20 . The membrane  30  material is selected to fill the top cavity  22 , but not pass through the through-hole  24  into the lower cavities  22   a ,  22   b.    
     Turning to  FIG. 10 , insulated wire conductors  25  are shown positioned in the cavities  22 . When a wire conductor  25  is inserted into the grommet  20 , the wire conductor  25  pierces the membrane  30  to form an opening  32  in the membrane  30 . The wire conductor  25  then passes through the lower cavities  22   a ,  22   b  of the 3-riser seal  23  to mechanically and electrically connect with the connector  10 . Preferably, the wire conductor  25  connects to a contact within the connector  10 . The membrane  30  adheres to the outside surface of the wire conductor  25  and forms a seal around the wire conductor  25  about the opening  32 . 
     The formation of the membrane  30 , and the receipt of the membrane  30  in the cavity  22 , will now be explained. The membrane  30  is added to the cavity  22  after the grommet  20  is formed. The membrane  30  is therefore a separate element that is added to an existing grommet  20 . The membrane  30  is initially in the form of a liquid, which is placed into each of the cavities  22  of the grommet  20  by using a syringe or other dispensing device. The liquid substantially fills the entirety of each cavity  22 , but the viscosity and surface tension of the liquid prevent the liquid from extending beyond the top of each cavity  22 . Once in place, the membrane  30  substantially cures within an hour, and fully cures within about 72 hours. The membrane  30  forms an air tight seal of the cavity  22  and the interior of the grommet  20 . Preferably, a membrane  30  is formed over all of the cavities  22  of the grommet  20 , whether or not it is know whether a particular cavity  30  will receive a wire contact  25 . 
     In accordance with the preferred embodiment, the membrane  30  is a self-leveling silicone adhesive coating which adheres to a plastic grommet  20 . The membrane  30  is relatively viscous, with a preferred viscosity of about 30,000-40,000 cps. The membrane  30  is relatively soft, with a preferred hardness of about 25 durometer, shore A. The membrane  30  is sufficiently flexible to form a seal about the wire conductor  25 , yet also allow the wire conductor  25  to pierce the membrane  30  without having pieces of the membrane  30  shear off into the connector  10 . The wire conductors  25  easily penetrate the membrane  30 , and the membrane  30  provides a consistent puncture, irrespective of the material and properties of the grommet  20 . Accordingly, the membrane  30  material can be optimized for its purpose of providing an air tight or fluid tight seal which can be punctured without shearing. And, the grommet  20  material can be separately optimized for its purpose for any given application, which may vary substantially from the purpose of the membrane  30 . 
     The membrane  30  is also preferably translucent, so that it is easily visible when it is located in the cavity  22 . Because the membrane  30  is clear, the user is able to see the cavity  22  and the through-hole  24 , so that the wire conductor  25  may be easily positioned over and inserted into the through-hole  24 . An example of the silicone appropriate for use as the membrane  30  is offered by Silicone Solutions of Twinsburg, Ohio, product number SS-6001. 
     The invention includes a process in which a clear silicone membrane  30  is adhered to a wire sealing grommet  20  to plug some, or preferably all, contact cavities  22  of a grommet  20 . The membrane  30  is punctured when a wire conductor  25  with crimped contacts at its ends is inserted into the connector  10 . If the contact cavities  22  are not occupied by wire conductors  25 , then those cavities  22  remain sealed, so that sealing plugs  15  are not needed. The application of the membrane  30  can be incorporated into all connectors  10  with wire sealing grommets  20 . The step of sealing the cavities  22  is separate from the formation of the connector body  21  and/or the grommet  20 . Accordingly, the type of material used to form the connector body  21  and/or the grommet  20  and the membrane  30  may each be optimized for the particular application for which the connector  10  is desired. Additional, advantages of the present invention include that the connector  10  does not require sealing plugs  15 , the connector  10  is light weight, the membranes  30  prevent the entry of foreign object debris into the connector  10 , and the added installation time required to install sealing plugs  15  in the connector  10  is eliminated. 
     In the embodiment shown in  FIGS. 4-10 , the grommet  20  has a length of about 1.0 inches, a width of about 0.6 inches, and a thickness of about 0.3 inches. The cavities  22  each have a diameter of about 0.1 inches, and the through-holes  24  each have a diameter of about 0.03 inches. The connector  10 , therefore, may receive wire conductors  25  having diameters ranging from about 0.03 inches to 0.1 inches. These dimensions are provided for exemplary purposes only, and are not intended to limit the scope of the invention. In the preferred embodiment, the connector  10  includes a grommet  20  as discussed above. However, other types of connectors and devices may be used without departing from the scope of the invention. 
     The foregoing description and drawings should be considered as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not intended to be limited by the preferred embodiment. Numerous applications of the invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.