Abstract:
An electrical box hanger assembly for hanging an electrical fixture from a ceiling. All hardware required for mounting the electrical device is included with the assembly. An adjustable mounting bar includes sliding tubular members with end flanges for spanning between adjacent overhead joists. An electrical box is connected to the adjustable mounting bar by a one-piece mounting bracket and a single box mounting fastener. The mounting bracket includes integral tensioner tangs on the mounting bracket prevent backing out of the box mounting fastener after it is secured in place. Bar fasteners are used to securely fasten the mounting bar to the joists. Load bearing device fasteners used to secure the mounting ring of an electrical fixture to the electrical box. Oversize openings are provided in the top wall of the electrical box to ensure that the suspended load is borne by the clamp and mounting bar and not the electrical box.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional U.S. Application No. 62/129,875, filed Mar. 8, 2015, the contents of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to electrical junction boxes and more particularly to an adjustable hanger bar and electrical box combination for hanging an electrical fixture or component from an overhead support. 
     BACKGROUND 
     Electrical boxes are commonly mounted on ceilings for the purpose of supporting ceiling fans, light fixtures, or other electrical devices. The electrical box provides a safe enclosure to house all wiring connections. Typically, these electrical boxes are secured to the ceiling by a supporting device that spans between two adjacent ceiling joists. 
     Various considerations are necessary in providing supporting devices for ceiling-mounted electrical boxes. The National Electrical Code specifies a minimum weight of 50 pounds for ceiling light fixtures and a maximum weight of 70 pounds for ceiling fans. It is therefore very important that an installer use adequate load-bearing fasteners for securing the supporting device to the overhead joists. It is also important that the load be carried by the supporting device, and not by the electrical box. 
     A second consideration arises from the awkwardness of working overhead. Typically, when securing a supporting device and an electrical box to the overhead structure of the ceiling, the installer must assemble several items together while reaching overhead. These include the mounting bar, the electrical box, the fasteners for securing the mounting bar to the ceiling structure, and the fasteners for mounting the electrical box to the mounting bar. Considering that the installer is typically on a ladder and reaching upwards, this creates a challenging task for any installer. It is therefore imperative that all parts necessary for a successful installation are on hand for the installer. 
     For installation of fan fixtures, a further consideration is that the electrical box must be connected support device must be as simple as possible. Many prior art supporting devices require the use of two-piece mounting brackets and multiple fasteners for attaching the electrical box to the support device, which creates a difficult assembly task for the installer as several components must be handled while at the same time supporting the overhead support device. 
     Accordingly, it would be advantageous to supply a support device that simplifies the procedure for hanging an electrical box or fixture from overhead joists while freeing up the installer&#39;s hands. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is an adjustable mounting bar and electrical box assembly for hanging a light fixture, fan, or other electrical device from a ceiling. All hardware required for mounting the electrical device is included as part of the assembly thereby eliminating the need for separate bagged parts or pieces to lose. The adjustable mounting bar includes sliding tubular members with end flanges for spanning between adjacent overhead joists. An electrical box is connected to the tubular members by a clamp and a single clamping fastener, which can be loosened to adjust the location of the electrical box with respect to the adjustable mounting bar. The end flanges include a nailing tooth that can be driven into the overhead joists to temporarily secure the adjustable mounting bar to the joists and thereby free the installer&#39;s hands for subsequent installation tasks. Bar mounting fasteners are threadably engaged in first storage receptacles in the sliding tubular members of the assembly and upon temporary securement to the joists, can be removed from the first storage receptacles and fastened through the end flanges to securely fasten the mounting bar to the joists. The assembly includes fixture mounting fasteners that are threadably engaged in second storage receptacles in the electrical box. After the mounting bar is secured to the joists and the electrical box is secured to the mounting bar, the device fasteners can be removed from the second storage receptacles and the mounting ring of an electrical device or fixture brought into engagement with the lower edge of the electrical box. The box mounting screw is then driven through the electrical box, through the elongated slot in the adjustable bars, and into a threaded box attachment bore in the clamp. Oversize openings are provided in the top wall of the electrical box to ensure that the entire suspended load is borne by the clamp and the mounting bars and not the electrical box. 
     OBJECTS AND ADVANTAGES 
     A first object is to supply a complete mounting assembly for mounting an electrical device to a ceiling, including all of the required fastening hardware. All of the installation hardware that is required to complete the task is provided as a part of the mounting assembly, including all required fasteners. 
     A further object is to provide a box mounting bracket with integral tension tangs that prevent backing out of box mounting fasteners while withstanding vibration of a fan or similar device. 
     A further object of the invention is the provision of an alignment tab on the electrical box for rapidly aligning the electrical box with respect to the adjustable bars and to the box mounting bracket. 
     Another object of the invention is to enable a secure mounting of an electrical box to an adjustable hanger bar by use of a single fastener. 
     An additional advantage is that the required fasteners are held securely in the electrical box mounting assembly in temporary storage receptacles. The temporary storage receptacles provide an advantage in that the fasteners are held securely in the assembly until they are ready to be used. The required fastening hardware is therefore on hand for installation at the time it is required. By freeing up an installer&#39;s hands, the task of mounting an electrical device to a ceiling is therefore greatly simplified and the installation time greatly reduced. Additionally, by having all of the required fastening hardware on hand, the installer is not burdened by the task of locating appropriate fasteners at the appropriate time. 
     The electrical box mounting assembly also provides the advantage that all of the load is supported by the supporting bars and the clamp, and not by the electrical box itself. 
     A further advantage is that the fastening hardware, while in storage in the temporary storage receptacles, does not extend beyond the outer periphery of the bars and end flanges. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Reference is made herein to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  is an isometric view of an electrical box hanger assembly, in accordance with embodiments of the invention. 
         FIG. 2  is a bottom view of an electrical box that forms a portion of the electrical box assembly of  FIG. 1 . 
         FIG. 3  is a side view of the electrical box as viewed along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a sectional view of the electrical box taken along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a top view of an electrical box that forms a portion of the electrical box assembly of  FIG. 1 . 
         FIG. 6  is an isometric view of the electrical box as viewed from the bottom or open end. 
         FIG. 7  is an isometric view of the electrical box as viewed from the top or closed end. 
         FIG. 8  is a plan view of a male hanger bar according to the present invention. 
         FIG. 9  is a side view of the male hanger bar of  FIG. 8 . 
         FIG. 10  is a sectional view of the male hanger bar taken along line  10 - 10  of  FIG. 9 . 
         FIG. 11  is a plan view of a female hanger bar according to the present invention. 
         FIG. 12  is a side view of the female hanger bar of  FIG. 8 . 
         FIG. 13  is a sectional view of the female hanger bar taken along line  13 - 13  of  FIG. 12 . 
         FIG. 14  is a plan view of an anchor tab that forms a portion of the end plate of each hanger bar according to the present invention. 
         FIG. 15  is a sectional view of the anchor tab taken along line  15 - 15  of  FIG. 14 . 
         FIG. 16  is an end view of the electrical box hanger assembly of  FIG. 1 . 
         FIG. 17  is a plan view of an adjustable hanger bar according to the present invention. 
         FIG. 18  is a sectional view of the adjustable hanger bar of  FIG. 17 . 
         FIG. 19  is a top view of an electrical box mounting bracket that forms a portion of the electrical box hanger assembly of  FIG. 1 . 
         FIG. 20  is a side view of the electrical box mounting bracket. 
         FIG. 20A  is a detail view of the end portion of the electrical box mounting bracket. 
         FIG. 21  is an isometric view of the electrical box mounting bracket. 
         FIG. 22  is an end view of the electrical box hanger assembly of the present invention, depicting the electrical box in relation to the hanger bars, box mounting bracket, and end plates of the assembly. 
         FIG. 23  is an exploded isometric view of an electrical box hanger assembly, in accordance with embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , there is shown a preferred embodiment of an electrical box hanger assembly  20  according to the present invention. The adjustable hanger bar assembly  20  includes an adjustable hanger assembly  22  that includes an inner bar member  24  and an outer bar member  26 . The inner bar member  24  is slideable within the outer bar member  26  of the adjustable hanger assembly  22 , thereby creating an interior channel  28  and parallel bottom lips  30  that define an elongated longitudinal slot  32  running lengthwise along the adjustable hanger assembly  22 . The electrical box hanger assembly  20  includes a fan box assembly  34  (see  FIG. 1 ) that is secured to the adjustable bar hanger  22  with a flat mounting bracket  35  that is positioned inside the interior channel  28  of the adjustable hanger assembly  22 . 
     Referring to  FIGS. 2-5 , the fan box assembly  34  includes an electrical box or fan box  36  with four flat walls  38 , four arcuate walls  40 , a rim  41 , and a top wall  42  defining an electrical enclosure  44  therein. Lugs  46  extend from the rim  41  of two opposing arcuate walls  40 . The lugs  46  are located substantially 180 degrees apart on opposing sides of the electrical box. Apertures  48  in lugs  46  are in coaxial with slots  50  in top wall  42  of electrical box  36 . One or more knockout openings  52  are provided in the top wall  42  and the knockout openings may include a nonmetallic electrical cable fitting  54  as shown in the top right corner of  FIG. 2 , such as the Black Button™ push-in fitting or connector for connecting non-metallic cable to electrical boxes. The Black Button™ push-in fitting is available from Arlington Industries of Scranton, Pa. Use of the push-in fitting  54  will enable push-in connection of a non-metallic cable (not shown) to the fan box  36 . 
     Top wall  42  of electrical box  36  further includes a box assembly aperture  55  two fixture mounting screws  56  and a grounding screw  57  as shown in  FIG. 2 . Top wall  42  of electrical box  36  further includes a plurality of bar engagement tabs  58  bent outward of the top wall and an alignment tab  60  bent outward of the top wall. Bar engagement tabs  58  define a bar engagement channel  62  as shown by distance D1 in  FIG. 5 . Bar engagement tabs  58  preferably extend by at least distance D2 from top wall  42  as shown in  FIG. 3 . As shown in  FIG. 5 , top wall  42  includes two threaded storage bores  63 , for captivity holding fixture mounting screws  56  (see  FIG. 4 ) with the electrical box  36  until they are required for installation of the electrical box hanger assembly  20  to a rafter or similar overhead support. As the fixture mounting screws  56  are of substantial length (see  FIG. 1 ), it is critical that the threaded storage bores  63  and the fixture mounting screws  56  are located outside of the bar engagement channel  62  of the electrical box  36 . Thus the fixture mounting screws  56  will be positioned to the side of the adjustable hanger assembly  22  and will not interfere with connection of electrical box  36  to adjustable hanger assembly  22  prior to the fixture mounting screws being used to secure a light or fan fixture to the electrical box hanger assembly  20 . 
     The electrical box  36  of the present invention may be constructed of metal or plastic. If constructed of metal, it is preferably constructed of steel, and most preferably of 0.062-inch AISI 1010 steel that is galvanized with a minimum zinc plating thickness of 0.0005-inch. As shown in  FIG. 4 , the lugs  46  include a bottom face  64  that is substantially planar with the lower edge  66  of the electrical box  36 . 
     With reference to  FIGS. 8-13 , the inner bar member  24  and outer bar member  26  each include an end plate  68  with a top end  70  and a bottom end  72 . An alignment tab  74  extends from the bottom end  72  of the end plate and a nailing tooth  76  is lanced from and bent inward of the end plate. As shown particularly in  FIGS. 10 and 13 , the bar members  24  and  26  are substantially U-shaped and include a top wall  78  and two side walls  80 . Paired threaded bores  81  (see  FIGS. 10 and 13 ) are provided in the side walls  80  of the bar members  24  and  26  substantially near the end plates  68 . The bar members  24  and  26  are preferably formed from 1010 sheet steel with a minimum thickness of 0.046 inch and are zinc-plated. 
     As shown in  FIGS. 14 and 15 , the nailing tooth  76  includes a base end  82  where it is integral with the end plate  68 , a sharp bend  84 , and a pointed tip  85 . As shown in  FIG. 16 , each end plate  68  includes a plurality of rows of slots  86   a ,  86   b , and  86   c  and indicia  87  thereon to indicate where the end plates should be aligned with respect to an overhead rafter or similar support in order to accommodate the desired thickness of ceiling wallboard. One or more nailing apertures  88  are provided in the end plate  68 . Referring to  FIGS. 17-18 , the adjustable hanger assembly  22  includes the inner bar  24  and outer bar  26  assembled together, with the inner bar slideable within the outer bar  26  and two bar fasteners  89  held captive within the side walls  80  of the bar members  24  and  26 . 
     Referring to  FIGS. 19-20 , the mounting bracket  35  is a substantially flat elongated metal bar having two ends  90 , and an upper surface  92  and a lower surface  94 . The mounting bracket  35  further includes an alignment slot  96 ; a threaded box attachment bore  98  and an associated box attachment boss  101  in axial alignment therewith. The mounting bracket  35  also includes threaded fixture attachment bores  103  and an associated fixture attachment boss  105  in axial alignment therewith. A tensioner tang  107  is provided on at least one corner  109  of the mounting bracket  35 . The tensioner tangs  107  are each defined by a longitudinal slit  111  in the mounting bracket and each tensioner tang is bent toward the lower surface  94  and out of the plane of the mounting bracket as shown in  FIG. 20A . Preferably, the mounting bracket  35  is constructed of steel and is at least 0.083 inch thick, as denoted by thickness D3 in  FIG. 20A . Threaded box attachment bore  98  is preferably centered on said mounting bracket  35 . 
     Referring to  FIG. 22 , when preparing to install the electrical box hanger assembly  20 , such as between two rafters (not shown), the inner bar member  24  resides within the outer bar member  26  and the two members are slideable with respect to one another. Bar engagement tabs  58  contact the side walls of the outer bar member  26  and quickly align the electrical box  36  with the adjustable hanger assembly  22 . A single box mounting screw  113  passes from the interior of electrical box  36  and through center hole in electrical box  36  and thence through center hole in mounting bracket  35 . For accommodating one-half inch thick wallboard, end plates  68  are aligned with the rafters with bottom tab  74  of the end plate  68  flush against the bottom edges of the rafters. To accommodate ¾-inch, 1-inch, or 1.25-inch thick wallboard, the end plates  68  of adjustable hanger assembly  22  is aligned respectively with row A of slots, row B of slots, or row C of slots. After the adjustable hanger assembly  22  is adjusted for wallboard thickness and is adjusted to fit between two parallel rafters, nailing tooth  76  is hammered into the rafter for each of the end plates  68  to temporarily secure the electrical box hanger assembly  20  to the rafters. Fasteners such as nails or screws (not shown) are then driven through nailing apertures into the rafters to permanently secure the adjustable hanger bar assembly to the rafters. For the assembly shown in  FIG. 22 , the resultant installation will then have bottom edge  114  of electrical box  36  aligned with the bottom surface  115  of the surrounding wallboard  117 . 
     With reference to  FIG. 23 , electrical box hanger assembly  20  includes adjustable hanger assembly  22  assembled with inner bar  24  nested within outer bar  26 . Mounting bracket  35  nests within channel  28  of adjustable bar assembly with tensioner tangs  107  of mounting bracket  35  sliding along lips  30  of adjustable hanger assembly  22 . End plates  68  are aligned for the correct wall board thickness and secured to the rafters (not shown). Mounting screw  113  is then driven through box assembly aperture  55  (see  FIG. 2 ) of electrical box  36  and threaded loosely into threaded box attachment bore  98  of mounting bracket  35 , after which electrical box  36  is assembled to mounting bracket and mounting bracket  35  and electrical box  36  assembly are then slideable with respect to adjustable hanger assembly  22 . After the nailing tooth  76  of each end plate  68  is nailed into the respective rafter (not shown), the electrical box  36  may be secured at the desired position along the adjustable hanger assembly  22  by tightening mounting screw  113  into mounting bracket  35 . Fixture mounting screws  56  may then be removed from their captive position in paired threaded bores  78  (see  FIG. 5 ) and passed through holes in fixture mount (not shown) and passed through lugs  46  of electrical box  36  and tightened into threaded fixture attachment bores  103  of mounting bracket  35  to secure the mounting bracket (not shown) of an electrical fixture, such as a ceiling fan or light fixture, to the electrical box hanger assembly  20  and thus securely to the overhead rafters. 
     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. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiments herein were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention.