Abstract:
A hanger assembly for supporting an electrical box above a drop ceiling having a grid supporting structure. The assembly includes an elongated one-piece bar with a U-shaped cross-section, an end bracket secured at each end of the bar, a center bracket, an anchor bar, and an electrical box. The end brackets include an inner leg for resting on the horizontal ledges of adjacent T-rails and arms for loosely fitting over the top of the T-rails. A fastening arrangement for securing the electrical box to the elongated bar enables mounting the electrical box in two ways. The electrical box can be mounted with its sides square with the bar or with the sides at a 45° angle to the bar. Mounting the electrical box with the sides at a 45° angle provides full access to all knockout apertures in the sidewalls of the electrical box.

Description:
FIELD OF THE INVENTION 
     This invention relates to supports for electrical junction boxes and specifically to an improved load bearing hanger for a suspended or drop ceiling. 
     BACKGROUND OF THE INVENTION 
     Electrical boxes are commonly installed above suspended or grid ceilings in order to provide secure enclosures for making electrical connections to supply the various electrical needs including lights, fans, and electrical outlets. Hangers for supporting such electrical boxes typically include anchoring structure above the electrical box to enable the electrical box to be tied off or supported from above by a chain, wire, or similar device. 
     Heretofore, hangers for grid ceilings typically provided a limited amount of knockouts or access apertures for the connection of conduit or cables. The limited amount of access apertures is typically a result of the anchoring structure interfering with access to each of knockouts on the electrical box. Thus an installer was limited in the amount of electrical conduit or cable that could be connected to the electrical box. 
     Accordingly, it would be advantageous to provide an electrical box hanger for supporting an electrical box above a suspended or drop ceiling in such a manner that all of the knockouts on the electrical box are available for use. Additionally, it would be advantageous to provide an electrical box hanger that was simple to install and could be manufactured at low cost. 
     SUMMARY OF THE INVENTION 
     The invention is a hanger assembly for supporting an electrical box above a drop ceiling having a grid supporting structure. The assembly includes an elongated one-piece bar with a U-shaped cross-section, an end bracket secured at each end of the bar, a center bracket, an anchor bar, and an electrical box. The end brackets include an inner leg for resting on the horizontal ledges of adjacent T-rails and arms for loosely fitting over the top of the T-rails. A fastening arrangement for securing the electrical box to the elongated bar enables mounting the electrical box in two ways. The electrical box can be mounted with its sides square with the bar or with the sides at a 45° angle to the bar. Mounting the electrical box with the sides at a 45° angle provides full access to all knockout apertures in the sidewalls of the electrical box. 
     OBJECTS AND ADVANTAGES 
     Several advantages are achieved with the suspended ceiling electrical box hanger assembly of the present invention, including:
         (1) The hanger assembly is an assembly of components that can be manufactured at low cost. Many of the parts, including the bar and end brackets, may be stamped and shaped from sheet metal. This lowers the cost of production of the support assembly.   (2) The hanger assembly enables an installer to mount the electrical box to the bar in such a manner that knockouts on all four sides of the electrical box will be available for making connections, thus greatly enhancing the functionality of the electrical box.   (3) Ample clearance is provided between the arms and end plate of each end bracket. This enables rapid placement and mounting of the electrical box hanger assembly over the bulb portions of adjacent T-rails in a drop ceiling.   (4) An anchor bar, provided for supporting the hanger assembly from an overhead structure, is integral with the elongated bar thereby having the advantage of supporting the load from the bar rather than from the electrical box.   (5) The hanger assembly includes an elongated bar and a center bracket having U-shaped cross-sections that advantageously provide extensive surface contact between them when secured together to support an electrical box.       

     These and other objects and advantages of the present invention will be better understood by reading the following description along with reference to the drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a preferred embodiment of a suspended ceiling junction box hanger assembly according to the present invention. 
         FIG. 2  is a top view of an elongated hanger bar that forms a portion of the hanger assembly of  FIG. 1 . 
         FIG. 3  is a side view of the hanger bar of  FIG. 2 . 
         FIG. 4  is an end view of the hanger bar. 
         FIG. 5  is a front elevation view of an end piece that forms a portion of the hanger assembly of  FIG. 1 . 
         FIG. 6  is a top view of the end piece depicted in  FIG. 5 . 
         FIG. 7  is an end view of the end piece depicted in  FIG. 5 . 
         FIG. 8  is a perspective view of the end piece. 
         FIG. 9  is a top view of an electrical box that forms a portion of the hanger assembly of  FIG. 1 . 
         FIG. 10  is a side view of the electrical box of  FIG. 9 . 
         FIG. 11  is a sectional view of the electrical box taken along line  11 - 11  of  FIG. 9 . 
         FIG. 12  is a top view of a center bracket that forms a portion of the hanger assembly of  FIG. 1 . 
         FIG. 13  is an end view of the center bracket of  FIG. 12 . 
         FIG. 14  is a perspective view of the center bracket of  FIG. 12 . 
         FIG. 15  is a plan view of an anchor bar that forms a portion of the hanger assembly of  FIG. 1 . 
         FIG. 16  is a sectional view of the elongated bar with the anchor bar attached thereto. 
         FIG. 17  is a detail view of a portion of  FIG. 16  depicting the clip members attached to the elongated bar. 
         FIG. 18  is a perspective view of the suspended ceiling junction box hanger assembly installed on the rails of a grid support structure for a suspended ceiling. 
         FIG. 19  is a top view of the suspended ceiling junction box hanger assembly with the electrical box mounted in a second orientation wherein the sidewalls of the electrical box are square with respect to the longitudinal axis of the elongated bar. 
     
    
    
     TABLE OF NOMENCLATURE 
     The following is a listing of part numbers used in the drawings along with a brief description: 
     
       
         
               
               
             
               
               
             
           
               
                   
               
               
                 Part Number 
                 Description 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 20 
                 electrical box hanger assembly 
               
               
                 22 
                 elongated bar 
               
               
                 24 
                 electrical junction box 
               
               
                 26 
                 center bracket 
               
               
                 28 
                 end piece 
               
               
                 30 
                 anchor bar 
               
               
                 32 
                 base portion of bar 
               
               
                 34 
                 upward extending sides 
               
               
                 36 
                 ends of bar 
               
               
                 38 
                 paired slots and round apertures 
               
               
                 40 
                 slot 
               
               
                 42 
                 round aperture 
               
               
                 44 
                 end aperture 
               
               
                 46 
                 end plate 
               
               
                 48 
                 arm 
               
               
                 50 
                 U-shaped top member 
               
               
                 52 
                 aperture in arm 
               
               
                 54 
                 aperture in top member 
               
               
                 56 
                 aperture in end plate 
               
               
                 58 
                 side walls 
               
               
                 60 
                 end of end plate 
               
               
                 62 
                 leg of end plate 
               
               
                 64 
                 bottom edge of leg 
               
               
                 66 
                 bottom wall of junction box 
               
               
                 68 
                 sidewall 
               
               
                 70 
                 knockout 
               
               
                 72 
                 corner 
               
               
                 74 
                 tab 
               
               
                 76 
                 threaded fastener 
               
               
                 78 
                 raised area 
               
               
                 80 
                 inner cavity 
               
               
                 82 
                 threaded bore 
               
               
                 84 
                 grounding screw 
               
               
                 85 
                 bore in bottom wall of electrical box 
               
               
                 86 
                 base portion of center bracket 
               
               
                 88 
                 bottom 
               
               
                 90 
                 side 
               
               
                 92 
                 wing 
               
               
                 94 
                 threaded bore 
               
               
                 96 
                 threaded bore 
               
               
                 97 
                 axis through first pair of bores in center bracket 
               
               
                 98 
                 axis through second pair of bores in center bracket 
               
               
                 101 
                 top portion of anchor bar 
               
               
                 103 
                 leg of anchor bar 
               
               
                 105 
                 V-shaped projection 
               
               
                 107 
                 clip member 
               
               
                 109 
                 base portion of clip member 
               
               
                 111 
                 post 
               
               
                 113 
                 rivet 
               
               
                 115 
                 threaded fastener 
               
               
                 117 
                 T-rail 
               
               
                 119 
                 grid ceiling support structure 
               
               
                 121 
                 horizontal flange 
               
               
                 123 
                 longitudinal axis of elongated bar 
               
               
                 125 
                 electrical box cover plate 
               
               
                 127 
                 fastener 
               
               
                 Dl 
                 center to center distance between bores 
               
               
                 Θl 
                 angle between pairs of bores in center bracket 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention comprises a junction box hanger assembly for supporting an electrical junction box on a conventional suspended or drop ceiling. With reference to  FIG. 1 , there is shown a preferred embodiment of the electrical box hanger assembly  20  including an elongated bar  22 , an electrical junction box  24 , a center bracket  26 , two end pieces  28 , and a center anchor or anchor bar  30 . 
     Referring to  FIGS. 2-4 , the one-piece elongated bar  22  is of substantially U-shaped cross section and includes a base portion  32 , two upward extending sides  34 , and two ends  36 . The base portion  32  of the bar  22  includes two paired arrangements  38  of slots  40  and round apertures  42 . The base portion  32  further includes end apertures  44  substantially near the ends  36  of the bar. 
     With reference to  FIGS. 5-8 , the end pieces  28  each include an end plate  46 , two arms  48  extending outwardly and downwardly from the end plate  46 , and a U-shaped top member  50 . The end piece  28  further includes an aperture  52  in each of the arms  48 , an aperture  54  in the top member  50 , and a pair of apertures  56  in the end plate  46  with the apertures  56  in the end plate  46  axially aligned with the apertures  52  in each arm  48 . Upward extending side walls  58  are provided on the top member  50  portion of the end bracket  26 . The end plates  46  include two ends  60  and a downward extending leg  62  on each of the ends  60 . Each of the downward extending legs  62  of the end plates  46  includes a planar or flat bottom edge  64 . The apertures  56  in the end plate  46 , being axially aligned with the apertures  52  in the arms  48 , enable passage of a fastener (not shown) there through for anchoring the hanger assembly  20  to a grid support structure for a suspended ceiling. 
     Referring now to  FIGS. 9-11 , the electrical junction box  24  includes a bottom wall  66  and four sidewalls  68 . A plurality of knockouts  70  are located on the bottom wall  66  and the sidewalls  68 . The electrical junction box  24  includes four corners  72  and a bent over tab  74  with a threaded fastener  76  therein is provided at two of the opposing corners  72  arranged diagonally across from one another. As shown in  FIG. 11 , the bottom wall  66  of the electrical junction box  24  includes a raised area  78  pressed upward into the inner cavity  80  of the junction box. The raised area  78  includes a threaded bore  82  and a grounding screw  84  threaded therein. Two bores  85  are provided in the bottom wall  66  of the electrical junction box  24 . 
     With reference to  FIGS. 12-14 , the center bracket  26  includes a U-shaped base portion  86  including a bottom  88  and two sides  90  and further includes two wings  92  extending orthogonally from the sides  90 . Two pairs of paired threaded bores are provided in the wings  92  of the center bracket  26  including a first pair consisting of threaded bores  94  and a second pair consisting of threaded bores  96 . As shown in  FIG. 12 , the angle Θ 1  between the axis  97  through first pair of threaded bores  94  and the axis  98  through second pair of threaded bores  96  is preferably 45°. As is described hereinafter in the operation of the present invention, this angle is critical as it enables the electrical box  24  to be mounted square with the elongated bar  22  or at a 45° angle to the bar  22 , at which 45° angle the electrical box  24  will be positioned in such a manner that all knockouts  70  (see  FIG. 1 ) within the electrical box  24  will be available for use by the installer. The center to center distance D 1  between threaded bores  94  is also equal to the center to center distance D 1  between threaded bores  96 . An equal distance between threaded bores  94  and threaded bores  96  is critical as it insures that both pairs of threaded bores will match up with apertures  85  in electrical box  24  (see  FIG. 1 ) when the electrical box  24  is rotated 45° to change from the first orientation to the second orientation of the box  24  with respect to the bar  22 . 
     Referring to  FIG. 15 , the anchor bar  30  includes a top portion  101  and two legs  103  extending orthogonally from the top portion  101 . Top portion  101  includes a V-shaped projection  105  therein. The legs  103  of the anchor bar  30  include a clip member  107  thereon. The clip members  107  are substantially C-shaped with a base portion  109  substantially parallel with the top portion  101  and an upward extending post  111  substantially parallel with the legs  103 . 
     With reference to  FIG. 1 , the junction box hanger assembly  20  is provided as an assembly with the end pieces  28  integrally connected to the elongated bar  22  by rivets  113 , which are shown exploded away from the elongated bar  22  for clarity, with threaded fasteners  76  secured in the tabs  74  of the electrical junction box  24 . The junction box hanger assembly  20  includes anchor bar  30 , electrical box  24 , center bracket  26 , and threaded fasteners  115 , all of which can be supplied loosely in a package with the bar  22  and end piece  28  assembly or in an assembled state with electrical box  24  secured to the bar  22  by threaded fasteners  115  extending through threaded bores  94  or  96  of center bracket  26 . 
     The elongated bar  22  is preferably constructed of 0.046-inch thick American Iron and Steel Institute (AISI) grade 1010 steel with a galvanized coating. The electrical box  24  and center bracket  26  are preferably constructed of 16-gage AISI 1010 steel with a galvanized coating. The end pieces  28  are preferably constructed of 0.062-inch thick AISI 1010 steel with a galvanized coating. The anchor bar  30  is preferably formed from 1008 or 1010 AISI steel rod of 0.188-inch diameter with a galvanized coating. Fasteners  115  for securing electrical box  24  to the elongated bar  22  are preferably #8−32×0.60-inch long tri-drive round head screws with locking serrations. The junction box hanger assembly  20  can be produced at low cost as all the components produced from sheet metal can be stamped and bent into shape, with the electrical box typically constructed of three pieces and welded together, and the anchor bar  30  simply cut to length and formed into the desired shape. 
     With reference to  FIGS. 16-17 , the anchor bar  30  is secured to the elongated bar  22  by simply spreading the legs  103  slightly apart until base portions  109  of clip members  107  pass through slots  40  in base portion  32  of bar  22  and then pressing inward and upward on legs  103  until posts  111  pass through round apertures  42 . Thus connected to the bar  22 , anchor bar  30  can be secured at V-shaped projection  105  by a chain or wire (not shown) to an overhead support. 
     For operation of the junction box hanger assembly  20 , reference is made to  FIG. 18 . Junction box hanger assembly  20  is placed over the T-rails  117  of a grid ceiling support structure  119  by simply pressing arms  48  of end pieces  28  over the T-rails  117  until the legs  62  of end pieces  28  rest on the horizontal flange  121  of the T-rails  117 .  FIG. 18  depicts electrical box  24  mounted in a preferred orientation with respect to the elongated bar  22 , wherein the sidewalls  68  of the electrical box  24  are at a 45° angle with respect to the longitudinal axis  123  of the bar  22 . To mount the electrical box  24  at the 45° angle, the installer simply tightens fasteners  115  through bores  85  of electrical box  24  into threaded bores  94  in center bracket  26 . The electrical junction box  24  is tightened against the bar  22  until the bottom wall  66  of junction box  24  is flush against the top of the two upward extending sides  34  of the elongated bar  22  and wings  92  of center bracket  26  are flush against the bottom wall  66  of the electrical box  24 . As both the bar  22  and center bracket  26  are of U-shaped cross-section, securing the electrical box  24  to the bar  22  also brings bottom  88  and sides  90  of center bracket  26  flush against the base  32  and sides  34  respectively of elongated bar  22 , making for a conforming fit between the two U-shaped elements. After electrical cables or conduit (not shown) have been connected to the junction box  24  and wiring connections completed, a conventional electrical box cover plate  125 , as shown in  FIG. 18 , can be secured to the junction box  24  to seal off the inner cavity  80 . If desired, a fastener  127  may be driven through axially aligned apertures  52  in arm  48  and apertures  56  in end plate  46  to secure electrical box assembly to the grid ceiling support structure. 
     An alternative method of mounting the electrical box to the bar is with the sidewalls  68  of the electrical box  24  square with the elongated bar  22 . With reference to  FIG. 18 , this is accomplished by simply rotating the electrical box 45° counterclockwise with respect to the bar  22  and inserting threaded fasteners  115  through bores  85  in electrical box  24  and into threaded bores  96  in center bracket  26 . As the separation distance between bores  85  in electrical box  24  is equal to the separation distance between pair of threaded bores  94  and pair of threaded bores  96  respectively, center bracket  26  functions to mount electrical box  24  in either of two orientations with respect to the bar  22 . As shown in  FIG. 18 , mounting the electrical box  24  at a 45° angle with respect to the bar  22  provides the advantage of freeing all knockouts  70  for use by the electrician. When installing electrical cables or conduit above a suspended ceiling, it is frequently necessary to have all knockouts available for use. 
     Having thus described the invention with reference to a preferred embodiment, it is to be understood that the invention is not so limited by the description herein but is defined as follows by the appended claims.