Patent Publication Number: US-2013237071-A1

Title: Ground Clamp for Use with Ball Stud Ground Conductors

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     MICROFICHE/COPYRIGHT REFERENCE 
     Not Applicable. 
     FIELD 
     This disclosure relates to grounding assemblies used in the electrical utility industry as protective-grounding equipment, and more particularly to ground clamps for use with ball stud ground conductors. 
     BACKGROUND 
     Grounding assemblies including various types of clamps, ferrules, and interconnecting electrically conducting conduits in the form of cables are commonly used as protective equipment for lineworker or other personnel working around electric power lines. Ground clamps for use with ball stud ground conductors having a shaft that terminates in a spherical end are known. Such clamps are typically so call C-type clamps having a pair of generally C-shaped jaws that clamp the spherical end of the ball stud with the shaft of the ball stud extending through a pair of fingers that forming one of the jaws of the clamp. An example of such a clamp, as well as some ball studs, is shown in commonly owned, published U.S. patent application, Pub. No. US 2011/0081810, published Apr. 7, 2011. 
     When using ground clamps with ball studs, it is important that the jaws and the spherical end of the ball stud be properly aligned in the clamped condition. An improperly aligned clamp/spherical end can lead to an unintended release of the ball stud during lineworker maintenance or during a ground fault, which can create an unsafe situation. 
     SUMMARY 
     In accordance with one aspect of this disclosure, a ground clamp is provided for use with a ball stud, the ball stud having a shaft that terminates in a spherical end having a diameter larger than a diameter of the shaft. The ground clamp includes a body connectable to an electrical conduit to provide an electrically conductive connection, and first and second jaws extending from the body and movable relative to each other between an open position wherein a spherical end of a ball stud may be inserted into the clamp and a closed position wherein the spherical end of the ball stud can be clamped between the jaws to provided an electrically conductive connection between the clamp and the ball stud. The first jaw includes two fingers, each finger defining a C-shaped clamp surface that abuts the spherical end of the ball stud when the ball stud is inserted into the clamp. The two fingers are laterally spaced from each other to define a slot extending between the fingers and having a lateral width through which a shaft of the bail stud can extend when the ball stud is inserted into the clamp. The second jaw includes a laterally extending platform having a lateral width greater than the lateral width of the slot. The second jaw further includes a rib extending from the platform to be located within the slot between the two fingers with the jaws in the closed position. The second jaw has a concave clamp surface defined in the platform and the rib that partially surrounds the spherical end of the ball stud with the jaws in the closed position and the ball stud inserted in the clamp. The concave clamp surface on the rib is engageable with the spherical end of the ball stud as the jaws move from the open position to the closed position to guide the jaws and the spherical end of the ball stud into proper alignment in the closed position with the ball stud inserted into the clamp. 
     As one feature, the concave clamp surface is spherically shaped. 
     In one feature, the platform has a planar surface surrounding the concave clamp surface in the platform, and the concave clamp surface in the rib extends above the planar surface. 
     According to one feature, the jaws are translatable relative to each other along a longitudinal axis. 
     In a further feature, the platform has a planar surface surrounding the concave clamp surface in the platform and extending transverse to the longitudinal axis, and the concave clamp surface in the rib extends above the planar surface. 
     As one feature, the first jaw is fixed relative to the body and the second jaw is translatable relative to the body along the longitudinal axis. 
     According to one feature, the first jaw and the body are a one-piece component of the clamp. 
     As one feature, the ground clamp further includes a threaded member mounted in the body for rotation and extending parallel to the longitudinal axis, the threaded member operably engaged with the second jaw to translate the second jaw between the open and closed positions in response to rotation of the threaded member. 
     As a further feature, the second jaw includes a threaded boss engaged with the threaded member. 
     In one feature, the ground clamp further includes an actuating member operably associated with the jaws to actuate the jaws between the open and closed positions. 
     According to one feature, the body further includes a boss configured to receive an end of an electrical conduit to form an electrically conductive connection with the electrical conduit. 
     Other features and advantages will become apparent from a review of the entire specification, including the appended claims and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a ground clamp according to this disclosure, with the clamp shown in an open condition; 
         FIG. 2  is a side elevation of the ground clamp of  FIG. 1 , with the clamp again shown in an open condition; 
         FIG. 3  is a view similar to  FIG. 2 , but showing the clamp in a closed or clamped condition, with a ball stud clamped therein; 
         FIG. 4  if a front elevation of the ground clamp of  FIGS. 1-3 , with the clamp again shown in the open condition; 
         FIG. 5  is an enlarged top view of a movable jaw component of the clamp of  FIGS. 1-4 ; 
         FIG. 6  is a side view of the jaw component of  FIG. 5 ; 
         FIG. 7  is a section view taken along line  7 - 7  in  FIG. 5 ; and 
         FIG. 8  is a front view of the jaw of  FIGS. 5-7 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1-3 , a ground clamp  10  is shown for use with a ball stud  12 , the ball stud  12  being of any conventional and known construction and having a shaft  14  that terminates in a spherical ball or end  16  having a diameter D larger than the shaft diameter d. The ground clamp  10  includes a body  20 , a first or upper jaw  22 , a second or lower jaw  24 , and an actuating member  26 , operably associated with the jaws  22  and  24  to actuate the clamp  10  between the open position shown in  FIGS. 1 ,  2  and  4  and the clamped or closed position shown in  FIG. 3 . In the open position, the spherical end  16  of the ball stud  12  can be inserted into the clamp and in the closed position, the spherical end  16  of the ball stud  12  is clamped between the jaws  22  and  24  to provide an electrically conductive connection between the clamp  10  and the ball stud  12 . In the illustrated embodiment, the actuating member  26  is shown in the form of a threaded screw member  28  extending along a longitudinal axis  29 . 
     The body  20  includes a boss  30  for connection to an electrical conduit, shown diagrammatically at  32  in  FIGS. 2 and 3 , to provide an electrically conductive ground connection between the clamp  10  and the electrical ground conduit  32 . While any suitable construction can be used to provide the electrically conductive ground connection between the clamp  10  and the conduit  32 , in the illustrated embodiment the boss  30  has a bore  33  for receiving an end of the conduit  32 . The clamp  10  can further include a strain relief sleeve  34  of any conventional and known construction through which the electrical conduit  32  extends and which serves to reduce and/or relieve the strain on the electrical conduit  32  as it extends from the clamp  10 . The body  20  can further include an internally threaded boss  36  for receiving the threaded end of another bail stud (not shown). 
     The jaw  22  includes two fingers  40 , with each finger  40  defining a C-shaped damp surface  42  that abuts the spherical end  16  of the ball stud  12  when the ball stud  12  is inserted into the clamp  10 . The two fingers  40  are laterally spaced from each other to define an open ended slot  44  extending between the fingers  40  and having a lateral (perpendicular to the axis  29 ) width W 1  through which the shaft  14  of the ball stud  12  can extend when the ball stud  12  is inserted into the clamp  10 . In the illustrated embodiment, the housing  20  and the jaw  22 , including the two fingers  40 , are a one-piece component of the clamp  10 . 
     The second jaw  24  includes a laterally extending platform  50  having a lateral width W 2  greater than the lateral width W 1  of the open ended slot  44 . The jaw  24  further includes a rib  52  extending from the platform  50  to be located within the open ended slot  44  between the two fingers  40  with the jaws  22  and  24  in the closed position. The second jaw  24  has a concave clamp surface  54  defined in the platform  50  and the rib  52  that partially surrounds the spherical end  16  of the ball stud  12  with the jaws  22  and  24  in the closed position. In this regard, in the illustrated embodiment, the concave clamp surface  54  is spherically shaped and sized to conform to the spherical end  16  of the ball stud  12 . The concave clamp surface  54  on the rib  52  is engageable with the spherical end  16  of the ball stud  12  as the jaws  22  and  24  move from the open position to the closed position to guide the jaws  22  and  24  and the spherical end  16  into proper alignment in the closed position with the ball stud  12  inserted into the clamp  10 . The platform  52  has a planar surface  56  surrounding the concave clamp surface  54  and the concave clamp surface  54  and the rib  52  extends above the planar surface  56 , as best seen in  FIGS. 6 and 7 . 
     The threaded screw member  28  is offset from the clamp surfaces  42  and  54 , and the jaw  24  includes an internally threaded boss  60  that is engaged with the threaded member  28  so that the jaw  24  will translate between the open and closed positions parallel to the axis  29  in response to rotation of the threaded member  28 . In the illustrated embodiment, the threaded member  28  includes an enlarged portion  62  that abut an upper surface of the body  20 , a threaded shaft  64  that extends downwardly through a channel  66  formed in the body  20 , and an eye component  68  that is rotationally fixed to the shaft  64 , such as by a spring pin  70 , and abuts a lower surface of the body  20 . The jaw  24  includes parallel side walls  72  extending from the boss  60  to the platform  50  that slidably engage side walls  74  of the channel  66  to maintain alignment of the jaw  24  relative to the housing  20  and to react torsional forces generated when the threaded member  28  is rotated to translate the jaw  24  between the open and closed positions. It will be appreciated by those skilled in the art that the eye component  68  is engageable by one or more common tools employed by lineworkers. It should also be appreciated that while the threaded member  28  is shown as being offset relative to the clamp surfaces  42  and  54 , other constructions are possible, including one wherein the threaded member  28  underlies and/or is aligned with the clamp surfaces  42  and  54 . An example of such a construction is shown in previously referenced and commonly owned published U.S. patent application, Publication No. US 2011/0081810, published Apr. 7, 2011. 
     While any suitable mount construction can be used, the strain relief sleeve  34  is mounted via a bracket  75  and two bolts  76  that are received in threaded bosses  78  formed on the body  20  (only one bolt  76  and one boss  78  shown). 
     It should be understood that while certain embodiments have been illustrated and described herein, there are many possible forms for the various features of the clamp  10 . For example, while the actuating member  26  is shown in the form of the threaded member  28 , there are other possible constructions for an actuating member  26  that can move the jaws  22  and  24  relative to each other between the open and closed positions and that may be desirable depending upon the particular parameters of each application. As another example, while the platform  50  is shown as being rectangular when viewed from above, as best seen in  FIG. 5 , there are many possible shapes for the platform that may be desirable depending upon the particular parameters of each particular application. Accordingly, no limitation to any specific embodiment is intended unless it is expressly recited in one of the appended claims.