Abstract:
A fastener designed to press into two slots of a barrier and become captivated with spring tension barbs is disclosed. The fastener thus allows two vertical barriers to be fastened together by driving a screw through a first barrier, a second barrier, and then the fastener, to compress the barriers in place during assembly. The fastener may be provided with a nut holding cage with caged nut or a pair of thread engaging flanges to secure the screw to the fastener.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to fasteners and more particularly relates to a fastener for attaching to a barrier. 
     Motor control sections are designed with horizontal and vertical bus bar assemblies. The bus carries electrical current to plug-in units that operate motors in factories. The bus bar is energized during operation, requiring isolation of electrical current to prevent inadvertent contact. This may be accomplished by using two bus barriers. The barriers usually have internal grooves to hold each bus in position and keep them spaced properly to prevent short-circuiting. 
     Connections between adjacent vertical barriers of the prior art have previously typically been assembled vertically and required two assemblers to install nut and bolt type hardware. This method subsequently increases the labor cost of the assembly. Occasionally, inserts have been molded into an insulation barrier. Sometimes fasteners, such as PEM® brand self-clinching fasteners by Penn Engineering &amp; Manufacturing Corp., have been employed. Unfortunately, both of these additions have resulted in significantly increasing the part cost of the assembly. In yet another attempt to secure two vertical barriers, a fixture, not forming part of the assembly, has been employed to secure a nut to one barrier using self taping screws. Again, this method imparts substantial part cost and labor cost to the final assembly. 
     SUMMARY OF THE INVENTION 
     In an exemplary embodiment of the present invention, a fastener, for securing to a vertical barrier and allowing an adjacent barrier to be secured thereto, includes a main body portion having a first end and a second end, a first leg depending from the first end of the main body portion, and a second leg depending from the second end of the main body portion. The first leg and the second leg each having a mating end adjacent the main body portion and an unattached free end. The fastener further includes a first barb on the first leg and a second barb on the second leg. The first barb and the the second barb are each formed as a cutout portion having an attached end adjacent the free end of each respective leg and angled outwardly from each respective leg. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective view of a fastener and caged nut according to the present invention; 
     FIG. 2 is a top plan view of the fastener of FIG. 1; 
     FIG. 3 is a front plan view of the fastener of FIG. 1; 
     FIG. 4 is a side plan view of the fastener of FIG. 1; 
     FIG. 5 is a top perspective view of a fastener having thread engaging flanges according to the present invention; 
     FIG. 6 is a top plan view of the fastener of FIG. 5; 
     FIG. 7 is a side plan view of the fastener of FIG. 5; 
     FIG. 8 is a perspective view of a vertical bus barrier according to the present invention; 
     FIG. 9 is a partial side cross-sectional view of the fastener of FIG. 5 inserted within the vertical bus barrier of FIG. 8; 
     FIG. 10 is a perspective view of a pair of vertical bus barriers for holding vertical bus bars there between; 
     FIG. 11 is a side cross-sectional view of a pair of vertical bus barriers held together by a bolt and fastener of the present invention; 
     FIG. 12 is a front plan view of the vertical bus barrier of FIGS. 8-11 in use; 
     FIG. 13 is a front plan view showing horizontal and vertical bus bars with respect to the bus barriers of the present invention; and, 
     FIG. 14 is a front plan view of a three section motor control line up. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIGS. 1-4, a fastener  10  according to the present invention generally includes a main body portion  12 , a first leg  24  having a barb  32 , a second leg  37  having a barb  44 , and a nut holding cage  50 . 
     More specifically, the main body portion  12  may have a generally rectangular shape having a first end  14 , a second end  16 , a first side  18 , and a second side  20 . Centrally located within the main body portion  12  is a circular aperture  22 . 
     Depending from the first end  14  of the main body portion  12  is the first leg  24 . The first leg  24  may also have a generally rectangular shape with a mating end  26  which is adjacent the first end  14  of the main body portion  12 . Opposite the mating end  26  is a free end  28 . Within the first leg  24  is a cutout opening  30 . The material from the cutout  30  makes up a barb  32  which extends outwardly at an angle A from the first leg  24 . The barb  32  extends from the first leg  24  at its attached end  34 . The barb  32  ends at its projecting end  36 . The barb  32  is preferably spring biased with respect to the first leg  24  at an angle in the range of 5 to 45 degrees, and preferably about 25 degrees. 
     Depending from the second end  16  of the main body portion  12  is the second leg  37 . The second leg  37 , similar to the first leg  24 , may also have a generally rectangular shape with a mating end  38  which is adjacent the second end  16  of the main body portion  12 . Opposite the mating end  38  is a free end  40 . Within the second leg  37  is a cutout opening  42 . The material from the cutout  42  makes up a barb  44  which extends outwardly at an angle A from the second leg  37 . The barb  44  extends from the second leg  37  at its attached end  46 . The barb  44  ends at its projecting end  48 . The barb  44  is preferably spring biased with respect to the second leg  37  at an angle in the range of 5 to 45 degrees, and preferably about 25 degrees. 
     The nut holding cage  50  preferably includes a first holding arm  52  and a second holding arm  62  for securing a nut, e.g. nut  80 , therein. The cage  50  is preferably designed such that the screw hole  79  of the nut  80  is aligned with the screw accepting aperture  22  of the main body portion  12 . The first holding arm  52  may include a side member  54  extending from the first side  18  of the main body portion  12 . Two side flanges  58  and  60  and a top flange  56  preferably extend from the side member  54  to complete the first holding arm  52 . The second holding arm  62  may include a side member  64  extending from the second side  20  of the main body portion  12 . Two side flanges  68  and  70  and a top flange  66  preferably extend from the side member  64  to complete the second holding arm  62 . 
     Advantageously, the fastener  10  may be stamped from a single sheet of material and bent along bend lines  72  to form the present invention. Preferably, the first leg  24 , second leg  37 , side member  54 , and side member  64  may be bent along bend lines  72  at an approximate  90  degree angle from the main body portion  12 . Additionally, for the first and second holding arms  52 ,  62 , the side and top flanges  56 ,  58 ,  60 ,  66 ,  68 , and  70  may be bent along bend lines  72  at approximate 90 degree angles from their respective side members  54  and  64 . The barbs  32  and  44  may also be bent along bend lines  72  at the above described angle A from first and second legs  24  and  37 . The sheet of material may be spring steel and heat treated to form the fastener  10  of the present invention. 
     Turning now to FIGS. 5-7, the nut holding cage  50  is shown replaced by a screw retaining member  81  having a pair of thread engaging flanges. A first thread engaging flange  82  has a connected end  84  which extends from near the first end  14  of the main body portion  12  to an indented end  86  which is adapted for engaging with threads in a screw. A first section  88  extends from the connected end  84  at an angle B from the main body portion  12 . A second section  90  extends from the first section  88 , ending at the indented end  86 , and may be generally parallel to the main body portion  12 . Similarly, the second thread engaging flange  92  has a connected end  94  which extends from near the second end  16  of the main body portion  12  to an indented end  96  which is adapted for engaging with threads in a screw. A first section  98  extends from the connected end  94  at an angle B from the main body portion  12 . A second section  100  extends from the first section  98 , ending at the indented end  96 , and may be generally parallel to the main body portion  12 . The indented ends  86 ,  96  together form a generally circular aperture  102  for accepting a screw body in the direction indicated by arrow X. While the first thread engaging flange  82  may be the same size as the second thread engaging flange  92 , the second section  100  of the second thread engaging flange  92  may be larger than the second section  90  of the first thread engaging flange  82  and the first section  98  of the second thread engaging flange  92  may be smaller than the first section  88  of the first thread engaging flange  82  such that the first thread engaging flange  82  and the second thread engaging flange  92  engage threads of a screw at different heights along the screw body. The first and second thread engaging flanges  82 ,  92  may be cutout from the main body portion such that a cutout opening  104  is formed in the main body portion  12  and the flanges  82 ,  92  may bend along bend lines  72  as previously described. 
     FIGS. 8-11 show vertical bus barriers for accepting the fastener  10  of the present invention. The barriers  110  and  111  are termed “vertical bus barriers” because they sandwich vertical bus bars there between, as will be described. A first vertical bus barrier  110  is shown in FIG. 8. A second vertical bus barrier  111  is preferably a duplicate of first vertical bus barrier  110 , and therefore only the details of first vertical bus barrier  110  will be described. The assembly of second vertical bus barrier  111  to first vertical bus barrier  110  will be described below. The first vertical bus barrier  110  has a series of screw holes  112  passing through a first surface  114  and a second surface  116  of the vertical bus barrier  110 . The screw holes  112 , four in FIG. 8, are flanked by a pair of rectangular slots  118 ,  120 . Each slot  118 ,  120  has an opening  122  for accepting either the first leg  24  or the second leg  37  of the fastener  10 . Each slot  118 ,  120  further has an upper wall  124  with an inner wall surface  126  within the interior  128  of the slots  118 ,  120 , an outer wall surface  130  contiguous with the first surface  114  of the vertical bus barrier  110 , and an interior side wall surface  132  connecting the inner wall surface  126  and the outer wall surface  130 . Preferably, the distance d from the interior side wall surface  132  of a first slot  118  to the interior side wall surface  132  of a second slot  120  is substantially equal to (or slightly greater than) the length  1  of the main body portion  12  such that a fastener  10  may fit snugly within the slots  118 ,  120 . 
     When a fastener  10  is inserted into the slots  118 ,  120  by pushing the first and second legs  24 ,  37  into the slots  118 ,  120 , the barbs  32 ,  44  are compressed towards the first and second legs  24 ,  37 . That is, the angle A is reduced when the barbs  32 ,  44  slide along the interior side wall surface  132  from their attached ends  34 ,  46  to their projecting ends  36 ,  48 . Once the projecting ends  36 ,  48  are pushed past the interior side wall surface  132  of the slots  118 ,  120 , the barbs  32 ,  44  return to their biased position forming the angle A with respect to the first and second legs  24 ,  37 . In this biased position, the projecting ends  36 ,  48  abut against the inner wall surface  126  of the slots  118 ,  120  such that the fastener  10  cannot be removed, without significant force and effort, from the vertical bus barrier  110 . Thus, the fastener  10  is simply snapped into place. 
     Preferably, three bus bars are attached to the horizontal bus, aligned with the vertical cavities in the back and front barrier (first and second barriers  110 ,  111 ). A barrier assembly  115  utilizes two bus barriers  110  and  111  as shown in FIG.  10 . The fastener  10  is placed on a back or first barrier  110  as shown in FIG.  11 . Then, a second, front barrier  111  is turned  180  degrees. That is, when looking at a rear exploded perspective view of the barriers  110  and  111  as shown in FIG. 11, surface  114  of barrier  110  is shown, with surface  116  behind, and for barrier  111 , surface  116  is visible, with surface  114  behind. Both second surfaces  116  of the first barrier  110  and second barrier  111  are placed face to face in an abutting relationship. The bolt or screw  150  may then be passed through the screw hole  112  in the X direction from the first surface  114  of the barrier  111 . Since this barrier  111  has no fastener  10  installed, the bolt or screw head  152  may lie flush against the surface  114  when bolted together. Then, the shaft  154  of the bolt or screw  150  may pass through screw bole  112  of the barrier  111  and then the barrier  110  and finally past the first surface  114  of the barrier  110  threading into fastener  10  on back of the rear barrier  110 . The fastener of FIGS. 5-7 is shown in use in FIG.  9  and the fastener  10  of FIGS. 1-4 is shown in use in FIG.  11 . 
     Turning to FIG. 12, the vertical bus barriers  110  and  111  are used for sandwiching the vertical bus bars  160 , three shown. The vertical bus bars  160  pass through the cavities  140  (see FIG. 10) that are formed within each barrier  110  and  111 . The vertical bus bars  160  have a slim profile while passing through the barriers  110 ,  111  as shown at  162 . That is, the thickness of the vertical bus bars  160  is shown at  162 . Above the barriers  10  and  111 , the vertical bus bars  160  have a 90 degree twist as shown at  164  about the centerline of each bus bar  160  such that a wider profile  166  (from a front plan view) is shown in FIG.  13 . The wider profile  166 , or width of the vertical bus bars  160 , is used for connection to the flat horizontal bus bars  170 . One vertical bus bar  160  is bolted to each horizontal bus bar  170  at connecting sections  180 . 
     FIG. 14 shows a three section motor control line-up  190 . Vertical bus  160  is shown only in sections  192  and  194 , not in section  196 . The horizontal bus bars  170 , however, pass through all three sections. A bus barrier is installed in the front and back of each section. 
     The present invention eliminates the need for more expensive fasteners such as PEM brand self-clinching fasteners or molded inserts and nut &amp; bolt combination requiring two assemblers. Using the snap in fastener  10  is cost effective, requires no assembly tools and allows front assembly of the vertical bus barriers in sections, using standard bolt type hardware. The caged nut design of the fastener shown in FIGS. 1-4 meets 2½ thread engagement and essentially eliminates the possibility of pull through during short circuit testing. 
     The barrier assembly  115  is held securely through use of the fastener and bolt/screw combination such that vertical bus  160  may be retained in insulated internal grooves  140 , thus preventing the bus  160  from making contact with the other bus bars  160 . As shown, the fastener  10  is suited for motor control vertical bus barriers of the 18″ and 12″ type, however, use on other types and sizes of vertical bus barriers as well as other applications are within the scope of this invention. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.