Abstract:
This invention pertains to a ground connector for grounding a conduit to an enclosure. The ground connector includes a plurality of integral ears extending from an outer wall of the connector with these ears configured to receive a ground wire therein. A locking nut portion, when engaged with the connector, urges the ground wire against the ears to thereby mechanically and electrically secure the ground wire to the ground connector. The connector is further configured with a plurality of locking teeth that engage the enclosure to thereby at least mechanically (and preferably electrically) secure the connector to the enclosure.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to U.S. Provisional Patent Application No. 60/674,865, filed on Apr. 26, 2005, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention pertains in general to grounding connectors for use in load centers or other electrical enclosures to which metal conduit is connected and more particularly to a grounding bushing whose ground wire connection can be made regardless of the orientation of the bushing within the enclosure.  
       BACKGROUND OF THE INVENTION  
       [0003]     Local and national electric building codes require there to be a ground connection between electrical conduits and an enclosure such as a load center or the like. Such codes require this grounding path to be permanent and electrically continuous. Thus, to comply with such requirements, it is common for the installer to employ a secondary ground conductor or wire between these devices rather than rely solely upon the connection to the enclosure.  
         [0004]     To satisfy this requirement, many different types of grounding connectors have been designed that secure a ground wire between a load center/enclosure and a metal conduit. Examples of such devices are shown in U.S. Pat. No. 2,974,185, U.S. Pat. No. 3,492,625, U.S. Pat. No. 4,159,859 and U.S. Pat. No. 4,806,108.  
         [0005]     The earlier &#39;185 patent shows a grounding bushing having only two locations at which a ground wire connection can be made. This can be problematic if either of these two ground wire connecting locations end up being inaccessible due to the limited space within the load center/enclosure. The &#39;625 patent improves upon this earlier patent by providing a grounding bushing having three such locations where a ground wire can be secured thereto. The &#39;108 patent improves upon these former patents even further by providing a multitude of different locations where the ground wire connection can occur. The &#39;859 patent is unique in that not only does it show a multitude of different locations where the ground wire can be attached to the grounding bushing, but this patent also discloses a separate cable connector member  12  that can be rotated about its connection to the grounding bushing. This provides even more options for the installer to make the ground wire connection within the tight confines of the enclosure.  
         [0006]     U.S. Pat. No. 3,967,872 varies from the above in that a cradle type grounding lug is secured between or intermediate adjacent projections  18  rather than at these projection locations themselves as would be done according to the earlier cited patents.  
         [0007]     The number and location of ground wire connections is very important to the installer since the more ground wire connection points available, the less need there is for the installer to manipulate the bushing so as to make a connection point accessible. In the past, it was common for an installer to either un-tighten or over-tighten the bushing within the enclosure in order to align or get access to the connection point for the ground wire. Thus, it frequently occurred that an installer secured a ground wire to the connector, but the connector was not properly secured to the enclosure or the conduit. This, of course, is to be avoided at all costs! 
         [0008]     It should also be noted that, as shown in the above identified patents, it is quite common to require the installer to insert the ground wire into a separate clip, lug or device and then require the installer to turn a screw so as to secure the ground wire within the clip. Hence, in these types of situation, two potentially limiting issues must be overcome by the installer. First, the screw must be accessible and at such an angle so that it can be torqued as needed against the ground wire. In the tight confines of an electrical enclosure, it is more often the case that such accessibility is not possible and hence to make it accessible, the conduit connector must be compromised such as by being loosened. Second, the separate clip can be readily lost or it can project so far as to interfere with an adjacent connector such that the clip cannot be employed. Unfortunately, these issues do not surface until the connector is actually installed as it is not possible to know beforehand whether there will be a conflict or not. Thus, there always exists the possibility when using these types of clip ground wire connectors, that the situation at the installation site is such that the connector cannot be employed, or if employed, will not be installed as specified by the manufacturer.  
         [0009]     Further still, it is to be noted that many existing ground connectors are manufactured by casting. This is a costly and time-consuming manufacturing method and one that does not readily lend itself to streamlining or to large volumes. Thus, a simpler and quicker way to manufacture ground wire connectors is desirable.  
         [0010]     There is therefore a need to be able to install a ground wire connector without regard to the final position or location of the ground wire connector component. It is also desired to be able to install the connector without incurring any interference with adjacent connectors. Yet another desirable feature is to be able to install the connector as tight as needed knowing that there is no potential need to ‘back-off’ or over-tighten the connector in order to properly align the connector with the ground wire. Still another desirable feature is to be able to install the connector without being concerned whether access to the ground wire component will be blocked or not. A further desire is to employ a connector that can be readily installed with a minimum number of parts so as to streamline the assembly and reduce the possibility of lost or dropped components. Yet another desirable feature is to be assured of a permanent and electrically continuous ground path between the conduit and the enclosure. Still another desirable feature is to be able to manufacture such a connector in a cost effective manner that readily lends itself to high volumes. These and other objects and advantages of this invention will be described in greater detail below.  
       SUMMARY OF THE INVENTION  
       [0011]     A ground connector for grounding an electrical conduit includes a bushing having an outer wall and a plurality of ears integral with and extending from this outer wall. Each such ear is configured to define a ground wire receiving cavity. A separate locking member secured to the connector urges a ground wire into at least one of these ground wire receiving cavities.  
         [0012]     The present invention provides for a ground connector for grounding an electrical conduit including a bushing and a locking nut. The bushing includes a top end, a bottom end, a side wall therebetween. The side wall has an outer wall and an inner wall, a plurality of ears integral with and extending generally radially from the outer wall, each of said ears configured to define a ground wire receiving cavity. The locking nut is configured for securement to the bushing for urging a ground wire into at least one of the ground wire receiving cavities.  
         [0013]     The ground connector may include plurality of locking teeth extending from the outer wall, the locking teeth extending beyond the bottom end of the bushing, the locking teeth configured for engagement with an electrical enclosure. The teeth may be beveled to assist with engaging the bushing with the electrical enclosure.  
         [0014]     The ground wire receiving cavity may be further defined by the outer wall and/or at least one of said ears is curved. The ears are configured with a first mating structure and the locking nut is configured with a second mating structure. Mating the first mating structure with the second mating structure enables the locking nut to urge the ground wire into the ground wire receiving cavity. Additionally, the locking nut may have a tear-shaped geometry corresponding with contours of the ground wire receiving cavity to assist in guiding and securing the ground wire within the ground wire receiving cavity.  
         [0015]     The outer wall is partially threaded and the locking nut is matingly threaded. The locking nut urges the ground wire into at least one of the ground wire receiving cavity upon threading the locking nut with the outer wall.  
         [0016]     Further, the inner wall may include a protruding stop to prevent a conduit from extending toward the top end of the bushing beyond the stop. The stop may be an inwardly extending rim of the side wall. The rim has a top surface which may be a curved smooth surface to prevent abrasion to conduit pulled therethrough.  
         [0017]     The present invention provides for a ground connector for grounding an electrical conduit including a bushing having a top end, a bottom end, and a side wall therebetween. The side wall having an outer wall and an inner wall and is generally cylindrical in shape. The outer wall includes a plurality of ears and a plurality of locking teeth. The plurality of ears integral with and extending generally radially from the outer wall, each of the ears configured to define a ground wire receiving cavity. The plurality of locking teeth extend from the outer wall and extend beyond the bottom end of the bushing. The locking teeth are configured for engagement with an electrical enclosure. The inner wall includes an inwardly extending stop. The locking nut is configured for securement to the bushing. The locking nut includes ground wire lead-in geometry to urge a ground wire into at least one of the ground wire receiving cavities.  
         [0018]     The present invention also provides for a ground connector for grounding an electrical conduit including a bushing comprising a top end, a bottom end, a side wall therebetween. The side wall has a partially threaded outer wall with a plurality of ears and a plurality of locking teeth. The plurality of ears are integral with and extending generally radially from the outer wall to define a ground wire receiving cavity. The plurality of locking teeth extend from the outer wall beyond the bottom end of the bushing. The side wall inwardly folds over itself to define an inwardly extending stop. The locking nut has interior threading to mate with the threading of the outer wall of the bushing. The locking nut includes ground wire lead-in geometry to urge a ground wire into at least one of the ground wire receiving cavities. The lead-in geometry corresponds with the contours of the ground wire receiving cavity.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is a perspective view of the present invention.  
         [0020]      FIG. 2  is a top view of the invention of  FIG. 1 .  
         [0021]      FIG. 3  is a section view of the invention of  FIG. 2  along the line A-A.  
         [0022]      FIG. 4  is a perspective view of the bushing portion of the present invention.  
         [0023]      FIG. 5  is a top plan view of the invention of  FIG. 4 .  
         [0024]      FIG. 6  is a section view of the invention of  FIG. 5  taken along line B-B.  
         [0025]      FIG. 7  is a top perspective view of the locking nut portion of the present invention.  
         [0026]      FIG. 8  is a section view of the invention of  FIG. 7 .  
         [0027]      FIG. 9  is a front exploded perspective view of the present invention assembled onto a conduit and secured to a load center.  
         [0028]      FIG. 10  is an exploded sectional view of the invention shown in  FIG. 9 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]     Referring initially to  FIGS. 1-3 ,  9  and  10  there is shown ground wire connector  10  includes a grounding bushing portion  12  and ground wire locking nut portion  14 . Bushing  12  and locking nut  14  are secured together by cooperative attachment between the external threads  36  of the bushing  12  and the internal threads  38  of the locking nut  14 . Bushing  12  is also internally threaded  16  as shown in order to be secured to metal conduit  18  in the normal fashion for such a device. This manner of attachment requires a mating threaded end of metal conduit  18  to extend partially through an electrical enclosure  20  so that ground wire connector  10  can secure conduit  18  to the enclosure  20 . The bushing  12  includes internal stop  17  which is a smooth curved protrusion within the bushing opposite the conduit  18  entry side as shown in  FIG. 6 . The internal threads  16  of the bushing  12  ends at the internal stop  17 . The internal stop  17  serves a duel purpose. The internal stop  17  prevents the conduit  18  from extending through the brushing  12  beyond the internal stop  17 , averting the conduit  18  from extending too far into the box. Additionally, the internal stop  17  provides a smooth curved surface to pull wires  18  through the box without damaging the wires by cutting or abrasion thereto.  
         [0030]     Generally, a separate locking nut  22  would be secured to conduit  18  from one side of enclosure  20  (i.e. outside), and grounding bushing  12  is threaded onto conduit  18  at the other side (i.e. inside) which protrudes through the enclosure  20  up to the internal stop  17 . This grounding bushing  12  and/or the separate locking nut  22  would then be tightened to compress enclosure  20  therebetween in the normal fashion.  
         [0031]     Most notable about grounding bushing  12  are the multitude of projecting ears  24  used as shown to secure a ground wire  26  to connector  10 , as shown in  FIGS. 4-6 . Ears  24  are preferably curved upward away from the enclosure so as to readily accept a variety of differently sized ground wire  26  therein. Hence, ground wire receiving cavity  27  is defined by the curved portion of ears  24  and outer wall  29  of bushing  12 . These ears  24  are also spaced about every 45 degrees along the perimeter of bushing  12 . Of course, different spacings and different curvatures are equally likely, this arrangement merely being the preferred embodiment.  
         [0032]     Intermediate a few of these ears  24  are locking teeth  28 . These locking teeth  28  also extend outward from outer wall  29  of bushing  12 , but they are curved or directed downwardly in a direction opposite ears  24 . Locking teeth  28  preferably terminate at an edge, point or bevel  30  so as to be able to dig into enclosure  20 . As shown in  FIGS. 1 and 3 , these teeth  28  project or extend just slightly below the bottom  32  of bushing  12  so as to better engage with the surface of the enclosure  20  and complete a ground connection therewith. Hence, when enclosure  20  is compressed between bushing  12  and separate locking nut  22 , teeth  28  of bushing  12  dig into enclosure  20  from one side as separate locking nut  22  is tightened onto conduit  18  from the other side. This provides extra assurance that connector  10  is and will remain properly secured to enclosure  20 .  
         [0033]     By incorporating bushing  12  with such teeth  28 , connector  10  is able to eliminate one common components of prior art connectors, namely the internal and/or external locknuts. Thus, this design of connector  10  is now of fewer components and thus is less costly to manufacture and requires one less part to be assembled thereby improving installation time.  
         [0034]     It should also be noted that sides  34  of teeth  28  can be configured to extend radially from bushing  12  in a generally perpendicular direction so as to create a corner between sides  34  and outer wall  29  of bushing  12 , as shown in  FIG. 5 . This now permits an installer to apply a tool in the corner created and use that tool as a driver to more forcibly torque bushing  12  against enclosure  20  (or to release or un-thread bushing  12  from conduit  18 ). Alternatively, it is conceivable for portions of ears  24  to be likewise configured to create such a corner for the insertion of a driver so that the installer now has many more options to choose from.  
         [0035]     To retain ground wire  26  within ground wire receiving cavity  27  and against the curvature of ears  24 , ground wire locking nut  14  is threaded onto bushing  12 . These external threads  36  on bushing  12  are better shown in  FIGS. 1, 4 , and  6  and they mate with internal threads  38  along the interior surface of locking nut  14 . Locking nut  14  includes protrusion  15  which are used to secure or tighten the locking nut  14  onto the bushing  12 .  FIGS. 7 and 8  show locking nut  14  shaped with a tear-drop lower portion  23  to mate with the ground wire receiving cavity  27 . The lower portion  23  of the locking nut  14  assists in securing ground wires  26  within the ground wire receiving cavity  27 .  FIG. 3  shows locking nut  14  threaded on bushing  12  maintaining ground wire  26  within ground wire receiving cavity  27  and securely against the curvature of ears  24  so as to provide permanent and continuous electrical contact with the ground wire  26 . Preferably, locking nut  14  is made of metal, similar to that of bushing  12 , but it is also conceivable for locking nut  14  to be made of other material, such as an insulating material, so long as it is capable of retaining ground wire  26  against ears  24  for electrical connectivity.  
         [0036]     As indicated earlier, the curvature of ears  24  is such that a variety of differently sized ground wires  26  can be inserted within ground wire receiving cavity  27 .  FIG. 1  shows one size ground wire  26  secured against an ear  24  but other larger sized ground wire may be mounted against ears  24  and locking nut  14 . Of course, the smaller the size ground wire, the more that locking ring  14  may be threaded onto busing  12 .  
         [0037]     No matter the ground wire  26  size, however, electrical contact is now made between the ground wire  26  and ground wire receiving cavity  29  and in particular the inside curved surface of ears  24  as well as the sides of bushing  12  in addition to locking nut  14  (provided locking nut  14  is made of a conducting material). Hence, all sides of the ground wire  26  are now in electrical contact with connector  10  and not just its opposite sides as is the case in the prior art where the ground wire is pressed between a screw and an opposite seat. Thus, greater electrical contact with ground wire  26  is now possible.  
         [0038]     Another unique feature of connector  10  is that is can be manufactured by a stamping operation, it need not be cast. Such a stamping operation is quicker to accomplish and can accommodate the manufacture of many more such connectors  10  in the same amount of time. Such a manner of construction also lends itself to a greater degree of automation. Thus, this design provides not only for better electrical contact with the ground wire and employs fewer parts, it is also easier and cheaper to manufacture.  
         [0039]     To install connector  10 , a user would first separately thread locknut  22  or apply another stop onto the end of conduit  18  in the normal fashion and as is quite common in the industry. The projecting conduit end would then be inserted through an opening in electrical enclosure  20  as is also typical. From the inside of enclosure  20 , the installer would then thread bushing  12  onto the end of conduit  18  until the conduit abuts the internal stop  17  of bushing  12 . The separate locking nut  22  is then adjusted or tightened to remove any slack in the conduit between the bushing  12  and the locking nut  22  to allow the bushing  12  to tighten securely against enclosure  20 . To insure a secure installation, the installer oftentimes places a driver against an ear  24  or a tooth  28  and then applies more force, such as by hammering, to tightly compress enclosure  20  between bushing  12  and outside locknut  22 . Teeth  28 , which extend slightly below the bottom  32  of bushing  12 , would now dig into enclosure  20  and resist any un-tightening as well as make a ground connection between bushing  12  and enclosure  20 . The same can be said for any locknut  22  that may be configured with like teeth located on the outside of enclosure  20 .  
         [0040]     The user is now presented with numerous locations or ground wire receiving cavities  27  into which ground wire  26  may be placed. Since there are no set screws or separate clips to be employed in tightening the ground wire  26  against bushing  12 , the only concern of the installer is which cavity  27  the stripped ground wire  26  is to be placed. Obviously, ground wire  26  can be readily bent or deformed to accommodate one or more ear  24  on bushing  12 . Thus, under this arrangement, there is no need for the installer to be concerned with clearances or accessibility for a later screw or driver since these issues which occurred frequently in the prior art no longer apply with connector  10 .  
         [0041]     Once ground wire  26  is placed within one (or even more than one) cavity  27 , locking nut  14  is threaded onto bushing  12  to thereby trap and hence secure ground wire  26  in place. The tear-shaped portion  23  of the locking nut  14  assist in securing the ground wire  26  by sandwiching it between the ears  24  and the locking nut  14 , within the ground wire receiving cavity  27 . Locking nut  14  also biases ground wire  26  against ears  24  so as to insure electrical conductivity between the ground wire  26  and connector  10  and ultimately with enclosure  20 .  
         [0042]     While select preferred embodiments of this invention have been illustrated, many modifications may occur to those skilled in the art and therefore it is to be understood that these modifications are incorporated within these embodiments as fully as if they were fully illustrated and described herein.