The present invention relates generally to battery cable clamps and connectors, and more particularly to a quick twist connector suitable for use with marine batteries, which are typically recognized by their threaded battery posts. 
     BACKGROUND ART 
     It will be appreciated by those skilled in the art that most motor boats are now started by battery power utilizing a relatively standardized 12-volt battery having threaded metal posts for the opposing polarities of the battery to which connector cables are attached. Marine-type batteries with threaded posts are used in a number of other applications, and those typically heavy duty, deep cycle applications such as over-the-road trucks, fire trucks and buses, construction equipment, and RV-motor coaches. The standard connection to the battery terminal posts of a marine-type battery involves simply a battery cable having an end lug with an aperture that fits over the battery terminal post. A nut or wing nut is then fastened on the threaded post to hold the lug in place. 
     Many marine batteries will last for several years, especially when used sparingly as in some boats and vehicles. During the course of the life of a battery, corrosion buildup may occur and cause the bolt or nut to attach by corrosion to the battery post. For this reason, some marine battery components are made of brass or stainless steel. Nonetheless, corrosion may impair the proper transmission of battery power from the battery post through the lug to the battery cable thereby diminishing the electrical power available. To remedy the diminished transmission of power, the battery cable clamp and nut or bolt have to be removed, corrosion brushed away, and then replaced so that a solid connection between the lug and the post can be reestablished. In addition, batteries must often be disconnected for proper servicing of a vehicle and if the battery is spent, the old battery must be removed and replaced with a new one. In light of these circumstances, the securing nut or bolt must be removed and the seal of corrosion broken to remove the nut and lug from the post. Because of the corrosion of the nut or bolt to the threaded battery post, any of the processes of disconnecting and reconnecting power, cleaning the battery post, or replacing the battery can be time consuming and difficult. 
     The difficulties of removing a nut or bolt in confined space make it particularly desirable that a wing nut type fastener be utilized so that it is not frequently necessary to work with a wrench in restricted spaces. It is also desirable that the nut or bolt be removed with a small number of turn for reasons of speed and convenience. There are similar difficulties in threading a bolt in confined spaces, so that a self-setting fastener is preferred. In some situations, the threaded section of a bolt may be very long, and it is desirable to have a fastener that can slide over the threads and then be set where desired. 
     What is needed then, is a fastener that will overcome the problems with prior art devices and provide an easily removable and fastenable connector to hold the battery lug in place on a marine battery. In addition, on marine batteries it is common to utilize battery terminal covers to protect terminal connections from accidental shorts. Therefore, a connector that provides some degree of insulation may reduce the need for such additional insulating components. 
     SUMMARY OF THE INVENTION 
     Instead of a standard bolt or wing nut which attaches to a threaded marine battery post in a conventional manner, the split wing nut assembly of the present invention is able to fit around the threaded terminal post until only the last several turns of the thread required to securely fasten the battery cable lug onto the post. The split wing nut assembly is compressed as downward pressure forces left and right split nut portions together and then several turns of the winged sleeve cause the left and right nut portions to completely tighten the split wing nut assembly against the battery cable lug on the post. Similarly, when it is desired to remove the battery cable, only a few turns of the wing nut sleeve are required to create sufficient space for the left and right nut sections to separate and then move freely over the threaded battery post permitting rapid removal of the split wing nut assembly and the battery cable lug it was holding in place. The upper portion of the wing sleeve may be manufactured with an insulating coating, or in appropriate cases of insulating materials such as glass filled Nylon, to protect against some instances of accidental shorting. In addition, the sleeve encompassing the left and right nut sections may be formed of an insulating material. To realize a self-setting fastener, it is preferred that only one of the split nut portions be threaded. In this fashion, cross-threading is eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects of the invention will be explained in greater detail in connection with the following drawings of the preferred embodiment of the invention: 
         FIG. 1  is an exploded perspective view of the elements of a split wing nut battery cable fastener of the present invention. 
         FIG. 2A  is a perspective view of the winged sleeve of the split wing nut of the  FIG. 1 . 
         FIG. 2B  is a top plan view of the split wing nut of  FIG. 2A . 
         FIG. 2C  is a side sectional view of the split wing nut of  FIG. 2A  taken along the line C-C as shown in  FIG. 2B . 
         FIG. 2D  is a side sectional view of the split wing nut of  FIG. 2A  taken along the of  FIG. 2B . 
         FIG. 2E  is a bottom plan view of the split wing nut of  FIG. 2A . 
         FIG. 3A  is a perspective view of the sleeve cylinder of the retaining sleeve shown in  FIG. 4A . 
         FIG. 3B  is a top plan view of the sleeve cylinder of  FIG. 3A . 
         FIG. 3C  is a side sectional view of the sleeve cylinder of  FIG. 3A  taken along the line C-C of  FIG. 3B . 
         FIG. 4A  is a perspective view of the retaining sleeve of  FIG. 1  shown in isolation. 
         FIG. 4B  is a bottom plan view of the retaining sleeve of  FIG. 4A . 
         FIG. 4C  is a side sectional view of the retaining sleeve of  FIG. 4A  taken along the line C-C of  FIG. 4B . 
         FIG. 5A  is a perspective view of the sleeve cap shown fitted at the end of the sleeve cylinder in the retaining sleeve of  FIG. 4A . 
         FIG. 5B  is a bottom plan view of the sleeve cap of  FIG. 5A . 
         FIG. 5C  is a side sectional view of the sleeve cap of  FIG. 5A  taken along the line C-C of  FIG. 5B . 
         FIG. 6A  is a perspective view of the retaining ring shown in  FIG. 1 . 
         FIG. 6B  is a side plan view of the retaining ring of  FIG. 6A . 
         FIG. 6C  is a top plan view of the retaining ring of  FIG. 6A . 
         FIG. 7A  is a perspective view of a threaded nut section of the winged nut fastener shown in  FIG. 1 . 
         FIG. 7B  is a top plan view of the nut section of  FIG. 7A . 
         FIG. 7C  is a bottom plan view of the nut section of  FIG. 7A . 
         FIG. 7D  is a side plan view of the nut section of  FIG. 7A  taken along the line D-D in  FIG. 7B . 
         FIG. 7E  is a side plan view of the nut section of  FIG. 7A  taken along the line E-E in  FIG. 7B . 
         FIG. 8A  is a perspective view of an assembled split wing nut according to the present invention. 
         FIG. 8B  is a bottom plan view of the split wing nut fastener of  FIG. 8A . 
         FIG. 8C  is a side sectional view of the split wing nut fastener of  FIG. 8A  taken along the line C-C in  FIG. 8B . 
         FIG. 8D  is an enlarged view of the portion D marked in  FIG. 8C . 
         FIG. 8E  is an enlarged view of the portion E marked in  FIG. 8C . 
         FIG. 9  is a perspective view of prior art fasteners utilized on the threaded terminals of a typical marine battery. 
         FIG. 10  is an exploded perspective view of the elements of a split nut battery cable fastener of the present invention with a six-sided nut shaped grasping portion. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A description of the preferred embodiment of the present invention will be best understood by referring to  FIGS. 1-9  of the accompanying drawings wherein like numerals refer to like parts. 
     In the prior art as shown in  FIG. 9 , a typical marine battery  16  is provided with positive and negative battery terminal posts  17   a ,  17   b . In order to fasten battery cables  19   a ,  19   b  to create an electrical connection with battery terminal posts  17   a ,  17   b , the battery cables  19   a ,  19   b  terminate in a lug portion  18   a ,  18   b , having an opening  9  sized to fit about the battery terminal posts  17   a ,  17   b . A typical marine battery post might be about ⅜ of an inch in diameter with M6 thread. The lugs  18   a ,  18   b  are then held in place by fastening a nut  8  or wing nut  7  type fastener on the threads of terminal posts  17   a ,  17   b . These prior art fastening devices are unnecessarily slow, subject to binding due to corrosion, difficult to set on the threads of the posts  17   a ,  17   b  without cross-threading, and in confined spaces difficult to manipulate with a wrench, all the while providing no insulating protection against accidental short circuits. To provide insulation, it is common in the prior art to utilize additional insulating boots to cover the terminal posts  17   a ,  17   b  and fasteners  8 , 7 . 
     Accordingly, according to the present invention, a split wing nut assembly is provided, shown in its assembled form in  FIG. 8  and in exploded view in  FIG. 1 . The components of the illustrated split wing nut fastener include retaining sleeve  11  formed of sleeve cylinder  30  and sleeve cap  40 , retaining ring  12 , threaded left nut section  13  and unthreaded right nut section  14  and wing sleeve  15 . These components are shown in isolation in greater detail in the following drawings. 
       FIG. 2A  shows the wing sleeve  15  with a grasping portion such as wings  20 , a body such as cylindrical wall  21  which has an expanded wall portion  23  with a downwardly extending flange  24  defining an interior channel  25  between flange  24  and the distal section  27  of body  21 . Keys  26  protrude into the channel  25 . The cylindrical wall  21  defines an interior channel or lumen  22  which is of a dimension suitable to permit the unimpeded passage of a marine battery terminal post, or even a longer threaded bolt that might pass entirely through the split nut assembly. The grasping portion may be advantageously coated with a durable insulating material such as glass filled Nylon, or other polymers, thereby avoiding the need for an insulating boot to cover the terminal post, especially when the sleeve cylinder  30  is also insulated or made from an insulating material. 
       FIG. 3A  depicts the sleeve cylinder  30  which has an interior channel  31 , a slightly raised interior edge  34  at the top, the interior channel  31  having a slightly wider portion  32  toward the top, a narrower portion  33  as the channel proceeds downward, and an inwardly turned lip  35 . 
       FIG. 4A  shows the retaining sleeve  11  which comprises the sleeve cylinder  30  and sleeve cap  40 . The upper portion of sleeve cap  40  has flange  42  which will not pass through the inward lip  35  of sleeve cylinder  30  as shown in  FIG. 4C . Thus, a portion of side wall  43  of sleeve cap  40  extends beyond sleeve cylinder  30 , and the bottom  45  of sleeve cap  40  has an opening  41  with a tapered edge  46  to assist in guiding a battery terminal post into the opening  41 . Thus, the tapered edge  46  slopes rearward toward the opening  41 . 
       FIG. 5A  shows the sleeve cap  40  in isolation and particularly the outer flange  42  with upper outer surface  47  and tapered inner surface  44  defining opening  41 . The sleeve cap  40 , like the wing sleeve  15 , is preferably made of stainless steel or other strong non-corrosive material. 
       FIG. 6A  shows the retaining ring  12  comprising band  60  having an opening  61 , top surface  62  and bottom surface  63 . 
       FIG. 7  shows nut section  13  which is substantially the same angular size as nut section  14  in the illustrated embodiment, although it would be possible for one of the nut sections to be larger than the other, or for there to be more than two nut sections, for instance three sections of approximately 120° of curvature each rather than the illustrated two sections each of approximately 180° curvature. The nut section  13  has a top surface  50 , an upper flange  51 , body  52  with an inward notch toward the top, and a tapered bottom outer surface  56  generally matching the taper on the top surface  44  of sleeve cap  40 . The inner portion of body  52  has an upper wider cavity portion  54  and extends downward to threaded cavity portion  55  sized to fit on a standard threaded marine battery terminal post. The other nut section  14 , shown in  FIG. 1 , is preferably substantially identical to nut section  13 , except the cavity portion  55  is not threaded. In this fashion, when the nut sections  13 , 14  engage on the threads of the terminal posts  17   a ,  17   b , there is no possibility of cross-threading causing the nut to jam. Instead, the threads of nut section  13  engage with the threads of the terminal posts  17   a ,  17   b  and unthreaded nut section  14  glides smoothly around the post as the nut  10  is tightened. 
       FIG. 8  shows the assembled split wing nut fastener where it can be seen that the fastener is assembled by placing sleeve cap  40  within sleeve cylinder  30 , and if desired some adhesive may be utilized between flange  42  and lip  35  to securely hold sleeve cap  40  in its position at the bottom of sleeve cylinder  30 . Next, the wing sleeve split nut assembly is created by sliding the nut sections  13 ,  14  within the opening  61  of retaining ring  12  until the top surface  62  of band  60  is beneath the flange  51  of the half nut sections  13 ,  14 . Then, the retaining ring  12  and half nut sections  13 ,  14  are fit into the channel  25  (shown in  FIG. 2C ) between the lower section  27  of cylinder wall  21  and flange  24  of the wing sleeve  15 . Flange wall  24  is bent around the outside of band  60  and over a portion of the bottom surface  63  of the band  60 , as shown in  FIG. 8E , thereby clamping the band and nut section flange  51  securely into channel  25 . Due to notch back  53  at the top of nut sections  13 ,  14 , openings exist along the top surface  50  of the nut sections and detents such as key ridges  26  within channel  25  engage those open sections so that the half nut sections  13 ,  14 , rotate in unity with wing sleeve  15 . The final assembly step involves the rolling of edge  34  on the interior of sleeve cylinder  30  inward creating an inwardly facing flange so that the expanded cylinder wall  21  of the body portion of wing sleeve  15  will not exit from the sleeve cylinder. In order to provide some insulating protection, preferably at least the grasping portion of wing sleeve  15  is insulated, either by manufacture with insulating material or by coating with an insulating material. For instance, the wing sleeve  15  could be manufactured substantially from glass-filled Nylon and then be attached to a lower metal fitting defining flange  24  and channel  25 . Alternatively, the wing sleeve  15  can be made of metal and at least the grasping portion such as wings  20  can be coated with polyimide resin or other insulating material. In some embodiments, the grasping portion may be adapted to be turned with a tool, such as being adapted to the configuration of a six-sided nut for turning with a wrench. 
     In operation, the opening  41  in the sleeve cap and lumen  22  in the wing sleeve are slightly larger than a standard threaded marine battery terminal post. Indeed, even the cavities  55  of nut sections  13 ,  14  are spaced apart by more than the diameter of such a threaded terminal post. However, when downward pressure is exerted upon the wing sleeve  15 , the lower tapered bottom section  56  of nut portions  13 ,  14  are pressed against the tapered surface  44  of the sleeve cap. This causes the forward portions of the nut sections to pivot inward whereby the threaded portion  55  of nut portion  13  engages with threads on a threaded marine battery terminal post. Once the threaded section  55  has engaged, further tightening may only be accomplished by twisting the grasping portion of wing sleeve  15 . Tightening has the effect of both pulling the entire split nut wing fastener and the bottom  45  of sleeve cap  40  downward against a cable lug to ensure good contact between the cable lug and the terminal, and the additional effect of urging the nut sections  13 ,  14  more firmly against the interior tapered surface  44  of sleeve cap  40  so that nut portions  13 ,  14  are securely engaged against the threads of the terminal post  17   a ,  17   b . In operation, on a typical M6 thread terminal post, it is generally only necessary to turn the wing sleeve through a rotation of between about 180° to 360° in order to accomplish secure tightening of the split nut wing fastener. 
     Use of the fastener is not limited to marine battery terminal posts, as it may also be adapted to use on almost any threaded post for electrical or mechanical connections. Indeed, one significant use is to place a split nut fastener on a long threaded bolt, whereby the fastener may be moved freely along the bolt without spinning until the split nut sections are pushed forward and pivot inward. Once the split nut sections engage, the fastener is quickly tightened. Thus a quick connect fastener is provided. 
     Accordingly, the present invention provides quick connect and disconnect capability in a confined space with a grasping portion that often obviates the use of a wrench even in the presence of limited corrosion. If a wrench should be necessary, only a single turn of the fastener may be required in order to disengage the fastener from the terminal post. Furthermore, this invention provides a self-setting nut and may obviate the need for a separate insulating boot over the terminal. 
     Although preferred embodiments of the present invention have been disclosed in detail herein, it will be understood that various substitutions and modifications may be made to the disclosed embodiment described herein without departing from the scope and spirit of the present invention as recited in the appended claims.
The invention provides a split nut connector in which spaced apart nut sections enable the connector to slide over a threaded battery terminal post until contact is made with the battery cable lug and the threaded nut sections are pushed into engagement with the threaded battery terminal post enabling effective tightening of the nut with a minimal amount of rotation in the fastening direction.