Patent Abstract:
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 with the assembly. 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 outer clamping fasteners, which can be loosened to adjust the length of the adjustable mounting bar. The end flanges include penetrable tabs 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. The outer face of the end flanges include a series of rows of slots arranged horizontally thereon and forming a plurality of bend lines. To accommodate ceiling coverings of various thickness, the end flanges can be bent outwards at the proper bend line to position the lower end of the electrical box flush with the ceiling surface. Load bearing bar fasteners threadably engaged in temporary storage receptacles in the sliding tubular members are removed therefrom and fastened through the end flanges to securely fasten the mounting bar to the joists. Load bearing device fasteners threadably engaged in temporary storage receptacles in the electrical box are removed therefrom and driven into receptacles in the clamp to secure the electrical device to the mounting bar. 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 mounting bar and not the electrical box.

Full Description:
FIELD OF THE INVENTION 
   This invention relates to electrical junction boxes and specifically to an electrical box mounting assembly for mounting a fan or light fixture to a ceiling. 
   BACKGROUND OF THE INVENTION 
   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 maximum weight of 80 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, several separate items must be manipulated. 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, 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. 
   A third consideration is that the support device must be matched to an electrical box. Many supporting devices are meant to accommodate most commercial electrical boxes. This typically requires complex arrangements on the supporting device to accommodate a variety of boxes. 
   A further consideration arises as a result of the various different types of ceilings, each of a different thickness. It should be easy for an installer to mount the support device correctly on the overhead joists to position the bottom of the electrical box flush with the ceiling, regardless of the thickness of the ceiling. 
   Many supporting devices for ceiling fans and fixtures include an arrangement to temporarily secure the device to the ceiling joists including U.S. Pat. No. 5,934,631 to Becker, et al., U.S. Pat. No. 5,954,304 to Jorgensen, U.S. Pat. No. 5,938,157 to Reiker, and U.S. Pat. No. 6,098,945 to Korcz, and U.S. Pat. No. 6,332,597 to Korcz et al. 
   Although all of the above supporting devices include an arrangement for temporarily fastening the supporting device to overhead joists to free up an installer&#39;s hands, they are still not completely satisfactory for simplifying the remainder of the task for installing the electrical box and the light fixture or fan to the supporting device. 
   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 with the assembly. 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 outer clamping fasteners, which can be loosened to adjust the length of the adjustable mounting bar. The end flanges include penetrable tabs 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. The outer face of the end flanges include a series of rows of slots arranged horizontally thereon and forming a plurality of bend lines. To accommodate ceiling coverings of various thickness, the end flanges can be bent outwards at the proper bend line to position the lower end of the electrical box flush with the ceiling surface. Load bearing bar fasteners threadably engaged in temporary storage receptacles in the sliding tubular members are removed therefrom and fastened through the end flanges to securely fasten the mounting bar to the joists. Load bearing device fasteners threadably engaged in temporary storage receptacles in the electrical box are removed therefrom and driven into receptacles in the clamp to secure the electrical device to the mounting bar. 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 mounting bar and not the electrical box. 
   OBJECTS AND ADVANTAGES 
   The electrical box mounting assembly of the present invention provides 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. 
   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 the entire 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. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a preferred embodiment of an electrical box mounting assembly according to the present invention including an adjustable mounting bar and an electrical box assembly. 
       FIG. 2  is a bottom view of two tubular members that will be fitted together to form an adjustable mounting bar according to the present invention. 
       FIG. 3  is a side view of the two tubular members of  FIG. 2 . 
       FIG. 4  is a bottom view of the two tubular members of  FIG. 3  after they are fitted together to form the adjustable mounting bar of the present invention. 
       FIG. 5  is a cross-sectional view of the adjustable mounting bar taken along line  5 — 5  of  FIG. 4 . 
       FIG. 6  is a perspective view of the electrical box portion of the electrical box mounting assembly of  FIG. 1 . 
       FIG. 7  is a bottom view of the electrical box shown in  FIG. 6 . 
       FIG. 8  is a sectional view of the electrical box taken along line  8 — 8  of  FIG. 7 . 
       FIG. 9  is a perspective view of an outer clamping member that forms a portion of a clamping arrangement in the adjustable mounting bar and electrical box assembly of the present invention. 
       FIG. 10  is a perspective view of an inner bar that forms a portion of a clamping arrangement in the adjustable mounting bar and electrical box assembly of the present invention. 
       FIG. 11  is a cross-sectional view of the adjustable mounting bar taken along line  11 — 11  of  FIG. 12  and depicting the clamping arrangement portion of the present invention. 
       FIG. 12  is a bottom view of the adjustable mounting bar and electrical box assembly of  FIG. 1 . 
       FIG. 13  is an end view of the adjustable mounting bar taken along line  13 — 13  of  FIG. 3 . 
       FIG. 14  is a side view of the adjustable mounting bar and electrical box assembly of  FIG. 1 , overhead joists, and a ceiling fixture in position to be attached thereto on a ceiling with a thin ceiling cover. 
       FIG. 15  is a side view of the adjustable mounting bar and electrical box assembly of  FIG. 1 , overhead joists, and a ceiling fixture in position to be attached thereto on a ceiling with a thick ceiling cover. 
   

   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 mounting assembly 
             
             
               22 
               adjustable mounting bar 
             
             
               24 
               inner tubular member 
             
             
               26 
               outer tubular member 
             
             
               28 
               electrical box 
             
             
               30 
               outer end of inner tubular member 
             
             
               32 
               inner end of inner tubular member 
             
             
               34 
               outer end of outer tubular member 
             
             
               36 
               inner end of outer tubular member 
             
             
               38 
               bottom sides of tubular members 
             
             
               40 
               longitudinal slot 
             
             
               42 
               lip 
             
             
               44 
               end flange 
             
             
               46 
               top wall of electrical box 
             
             
               48 
               top surface of top wall 
             
             
               50 
               side walls of electrical box 
             
             
               52 
               bottom edge of side walls of electrical box 
             
             
               54 
               knockout areas 
             
             
               56 
               clamp arrangement 
             
             
               58 
               inner bar 
             
             
               60 
               outer clamping member 
             
             
               62 
               outer aperture in inner bar 
             
             
               64 
               inner aperture in inner bar 
             
             
               66 
               middle aperture in outer clamping member 
             
             
               68 
               inner threaded bore in outer clamping member 
             
             
               70 
               planar portion of outer clamping member 
             
             
               72 
               upturned edge 
             
             
               73 
               first fastener 
             
             
               74 
               outer clamping fastener 
             
             
               76 
               oversized opening in top wall of electrical box 
             
             
               78 
               receptacle 
             
             
               80 
               aperture in flange 
             
             
               82 
               inner face of flange 
             
             
               83 
               outer face of flange 
             
             
               84 
               V-shaped tab 
             
             
               86 
               joist 
             
             
               88 
               first temporary storage receptacle 
             
             
               90 
               second temporary storage receptacle 
             
             
               92 
               bar fastener 
             
             
               94 
               device fastener 
             
             
               98 
               outer edge of flange 
             
             
               100  
               mounting ring 
             
             
               102  
               electrical device 
             
             
               104  
               bent over portion of bottom edge of electrical box 
             
             
               106  
               alignment apertures 
             
             
               108  
               side portion of rectangular cross section 
             
             
               110  
               top surface of lip 
             
             
               111  
               inner channel within tubular members 
             
             
               112  
               aperture in top wall of electrical box for first fastener 
             
             
               114  
               aperture in top wall of electrical box for device fastener 
             
             
               116  
               grounding aperture 
             
             
               118  
               grounding screw 
             
             
               120  
               outer surface of end flange 
             
             
               122  
               row of apertures or slots 
             
             
                   124A 
               first bend line 
             
             
                   124B 
               second bend line 
             
             
                   124C 
               third bend line 
             
             
               126  
               indicia 
             
             
               128  
               outward facing seat 
             
             
               130  
               ceiling cover 
             
             
               132  
               bottom edge of end flange 
             
             
               134  
               line connecting bottom edge of end flanges 
             
             
               136  
               line level with ceiling surface 
             
             
               140  
               positioning arrangement 
             
             
                 
             
           
        
       
     
   
   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , there is depicted an electrical box mounting assembly  20  for securing an electrical device (not shown), such as a light fixture or a fan, to a ceiling. The electrical box mounting assembly  20  includes an adjustable mounting bar  22  including an inner  24  and an outer  26  tubular member, and an electrical box  28 . 
   Referring to  FIGS. 2–5 , the inner tubular member  24  has an outer end  30  and an inner end  32 . The outer tubular member  26  also has an outer end  34  and an inner end  36 . Both of the tubular members  24 ,  26  have rectangular cross sections. 
   As shown in  FIG. 5 , the inner tubular member  24  has a smaller rectangular cross section than the outer tubular member  26 , thereby enabling the inner tubular member  24  to be received in and slide with respect to the outer tubular member  26 . 
   With reference to  FIG. 2 , the bottom sides  38  of each tubular member  24 ,  26  include longitudinal slots  40 . Lips  42  surround the slots  40  and extend longitudinally along the bottom sides  38 . Each of the tubular members  24 ,  26  include an end flange  44  on their outer ends  30 ,  34 . 
   Referring to  FIGS. 6–8 , the electrical box  28  used with the electrical box mounting assembly of the present invention includes a top wall  46  having a top surface  48  and side walls  50  having a bottom edge  52 . The electrical box  28  may include knockout areas  54  which may be later removed as desired to allow for passage of wiring there through. 
   With reference to  FIGS. 9–10 , a clamp arrangement  56  is depicted. The clamp arrangement  56  includes an inner bar  58  and an outer clamping member  60 . The inner bar  58  includes outer  62  and inner  64  apertures that align respectively with middle  66  apertures and inner threaded bores  68  in the outer clamping member  60 . Outer clamping member  60  includes a planar portion  70  and upturned edges  72  at a 90 degree angle to the planar portion  70 . 
   Referring to  FIGS. 11 and 12 , the outer clamping member  60  is secured to the top surface  48  of the electrical box  28  by first fasteners  73  through aperture  112  in the top wall  46  of the electrical box  28  and secured into the inner threaded bores  68  in the outer clamping member  60 . Outer clamping fasteners  74  connect the outer clamping member  60  to the inner bar  58  with the lips  42  of the bottom side  38  of the tubular members  24 ,  26  sandwiched there between. The inner bar  58  therefore is disposed within the inner tubular member  24  and rests on the lips  42  of the inner tubular member  24 . With the outer clamping fasteners  74  loosely holding the outer clamping member  60  to the inner bar  58 , the inner tubular member  24  can be easily slid within the outer tubular member  26  thereby adjusting the adjustable mounting bar  22  to the desired length. Since the outer clamping member  60  has already been secured tightly to the electrical box  28 , once the adjustable mounting bar  22  has been adjusted to the desired length, the electrical box  28  can be adjusted to the desired position on the mounting bar  22  whereupon the outer clamping fasteners  74  can be tightened into the inner bar  58  to lock the adjustable mounting bar  22  to the desired length and also lock the electrical box  28  in the desired position. Two outer clamping fasteners  74  are typically used. The top wall  46  of the electrical box  28  includes oversized openings  76  sized larger than the head of the outer clamping fasteners  74 , therefore allowing the electrical box  28 , after initial mounting, to be removed from the adjustable mounting bar  22  without changing the length of the bar  22 . The oversized openings  76  also insure that all of the weight of a suspended device is borne by the inner bar  58  and the tubular members  24 ,  26  and not by the electrical box  28 , which, as a result of the oversized openings  76 , escapes contact with the outer clamping fastener  74  and therefore does not support any of the suspended load. As shown in  FIG. 9 , the outer clamping member  60  further includes receptacles  78 , the function of which will be explained herein. 
   Referring to  FIG. 1 , the end flanges  44  of the inner  24  and outer  26  tubular members include apertures  80 , an inner face  82 , and a V-shaped tab  84  bent from the inner face  82  such that the tab  84  can be later hammered outwards to temporarily secure the adjustable mounting bar  22  to the joists (not shown). 
   A distinguishing feature of the preferred embodiment of the electrical box mounting assembly  20  is the inclusion of prepackaged fasteners to simplify its installation. The prepackaged fasteners are held in temporary storage receptacles to make them readily available to the installer at the time of installation. As can be readily appreciated by anyone who has installed an overhead light fixture or fan, the fact that all the work is overhead and the installer is typically on a ladder, makes the installation challenging. One of the most difficult aspects of the installation is freeing ones hands to obtain the various fasteners, making sure to obtain the correct fastener, handling the fastener and screwdriver, and inserting the fastener while keeping the fan or light fixture in the proper position. To ease the installation task the electrical box mounting assembly  20  therefore includes a first temporary storage receptacle  88  near the outer ends  30 ,  34  of the tubular members  24 ,  26  as shown in  FIG. 3  and two or more second temporary storage receptacles  90  in the top wall  46  of the electrical box  28  as shown in  FIGS. 6–8 . Prepackaged fasteners, as shown in  FIG. 1 , are stored in the temporary storage receptacles  88 ,  90  and include one or more bar fasteners  92  secured in the first temporary storage receptacles  88  and a device fastener  94  secured in the second temporary storage receptacle  90 . 
   The electrical box mounting assembly  20  is typically supplied as shown in  FIG. 1  but with the adjustable mounting bar  22  adjusted to its shortest length. As shown in  FIG. 11 , the outer clamping fasteners  74  are typically secured tightly to the inner bar  58  to lock the electrical box mounting assembly  20  to its shortest length. As supplied, the electrical box  28 , referring to  FIG. 1 , is held tightly to the adjustable mounting bar  22 , the bar fasteners  92  are held tightly in the first temporary storage receptacles  88 , and the device fasteners  94  are held tightly in the second temporary storage receptacles  90 . The device fasteners  94  are typically screws and the second temporary storage receptacles  90  are typically threaded bores. The device fasteners  94  are typically threaded into the second temporary storage receptacles  90  to a position in which the heads of the device fasteners  94  reside within the box and do not extend beyond a plane intersecting the bottom edge  52  of the electrical box  28 . The bar fasteners  92  typically do not extend beyond the outer edge  98  of the end flanges  44 . The electrical box mounting assembly  20  is therefore supplied in the smallest profile possible, with the bar fasteners  92  and device fasteners  94  not extending beyond the lateral extent of the electrical box  28  or the end flanges  44 . For shipment, storage, and sale the electrical box mounting assembly  20  as supplied can be easily packaged within a rectangular packaging container without any fear of the prepackaged fasteners  92 ,  94  snagging or catching on the container or of loosening or dislodging from the first  88  and second  90  temporary storage receptacles. Alternatively, the electrical box  28  could be packaged and sold separately of the adjustable mounting bar  22 , for example, to allow the consumer to choose an electrical box of a specific depth or shape, in which case the adjustable mounting bar  22  with the bar fasteners  92  temporarily stored therein would be packaged separately of the electrical box  28  with the device fasteners temporarily  94  stored therein. The explanation of the operation of the electrical box mounting assembly  20  that follows assumes the electrical box mounting assembly  20  is sold as a unit, with the electrical box  28  temporarily secured to the adjustable mounting bar  22 . 
   To place the electrical box mounting assembly  20  in operation, a suitable location is found on a ceiling. Referring to  FIG. 1 , the outer clamping fasteners  74  are loosened, allowing the adjustable mounting bar  22  to be adjusted in length and further allowing the electrical box  28  to be slid along the length of the adjustable mounting bar  22  to the desired location. 
   As shown in  FIG. 14 , the adjustable mounting bar  22  is adjusted to accommodate the distance between adjacent overhead joists  86  and the electrical box  28  is slid to the desired position on the mounting bar  22 . The outer clamping fasteners  74  are then tightened to lock the electrical box  28  to the mounting bar  22  and to lock the adjustable mounting bar  22  to its desired length to span the joists  86 . At this point in the installation procedure, the installer&#39;s hands are free and all of the required installation hardware is contained with the electrical box mounting assembly  20  in the form of the prepackaged fasteners  92 ,  94 . The installer then lifts the electrical box mounting assembly  20  into the desired position between the joists  86  and hammers the V-shaped tabs  84  into the joists  86  to temporarily hold the mounting assembly  20  to the joists. The installers hands are then free to remove the bar fasteners  92  one at a time and secure them through the flange apertures  80  and into the joists  86 . As shown in  FIG. 1 , a most preferred embodiment of the electrical box mounting assembly  20  includes four bar fasteners  92 . The bar fasteners  92  are load bearing fasteners that are rated to hold an 80 pound ceiling light fixture or a 70 pound ceiling fan as specified by the National Electrical Code. After the bar fasteners  92  have been installed, the installer&#39;s hands are again free to proceed with the installation. The device fasteners  94 , which are held tightly in the second temporary storage receptacles  90 , may then be removed, the mounting ring  100  of an electrical device, such as a ceiling fan or light fixture  102 , lifted in alignment with the bottom edge  52  of the electrical box  28 , and the device fasteners  94  threaded into the receptacles  78  (see  FIG. 7 ) to suspend the electrical device  102  from the electrical box mounting assembly  20 . The receptacles  78  are typically threaded bores within the outer clamping member  60  to accept the device fasteners  94 . 
   Referring to  FIGS. 6 and 9 , the bottom edge  52  of the electrical box  28  includes bent over portions  104  having alignment apertures  106  therein, the alignment apertures  106  situated to be in vertical alignment with the receptacles  78  in the outer clamping member  60 . 
   With reference to  FIG. 12 , prior to tightening the device fasteners  94 , wiring connections (not shown) can be completed between the housing electrical supply and the electrical device  102 . Once wiring connections are completed, the device fasteners  94  are tightened to secure the electrical device  102  to the electrical box mounting assembly  20 . 
   With reference to  FIG. 5 , it should be noted that the rectangular cross sections of the tubular members  24 ,  26  include side portions  108 . The lips  42  of both the inner  24  and outer  26  tubular members include a top surface  110  that is smooth to allow the inner tubular member  24  to slide smoothly upon the outer tubular member  26  and to also allow the inner bar (not shown) to slide smoothly upon the lips  42  of the inner tubular member  24 . As shown in  FIG. 5 , the top surface  110  of the lips  42 , which face the inner channel  111  within the tubular members  24 ,  26 , are at a non-oblique angle to the side portions  108 . 
   Referring to  FIG. 12 , it is critical that several dimensions and materials of construction are maintained within specifications to support the weight of the electrical box mounting assembly  20  and the electrical device  102  suspended there from. The inner  24  and outer  26  tubular members, the electrical box  28 , the outer clamping member  60 , and the inner bar  58  are typically constructed from steel to resist torsional bending and strain from the suspended electrical device  102 . The steel pieces are typically zinc-plated to render them rust resistant. The wall thickness of the tubular members  24 ,  26  is typically at least 0.038 inch. The inner bar  58  is at least 0.120 inch thick. The outer clamping member  60  is at least 0.050 inch thick. 
   With reference to  FIGS. 1 and 14 , the end flanges  44  are preferably at a 90 degree angle to the tubular members  24 ,  26  and the flanges  44  on each tubular member  24 ,  26  are of equal lengths. The bar fastener  92  will be load-bearing and is preferably a self-tapping machine screw no smaller than a #10 and no less than 1 inch in length. To accommodate the self-tapping machine screw bar fastener  92 , the first temporary storage receptacle  88  is preferably a circular aperture with a diameter of 0.172 inch. The size of the device fastener  94  would vary in length depending on the size of the electrical box  28 , but is preferably a 10-32 screw no less than 2.5 inches in length for an electrical box with a side wall of length 1.590 inch. The second temporary storage receptacles  90  are preferably threaded bores in the top wall  46  of the electrical box  28  threaded to match the threads on the device fastener  94 . 
   Referring to  FIGS. 6–8 , the top surface  48  of the electrical box  28  typically is planar. The preferred embodiment of the top wall  46  includes the second temporary storage receptacles  90  which are threaded bores that will accept device fasteners  94 , two apertures  112  that will accept first fasteners  73 , oversized openings  76  to accommodate the outer clamping fasteners  74 , apertures  114  to accommodate the device fasteners  94  when they are moved from the second temporary storage receptacles  90  to their receptacles, and a grounding aperture  116  which is a threaded bore to accept a grounding screw  118 . 
   Referring to  FIGS. 12 and 13 , the end flanges  44  of the adjustable mounting bar  22  include an outer surface  120  that includes a plurality of rows of parallel apertures or slots  122 . Each row of apertures  122  defines a separate bend line  124 A,  124 B,  124 C. Indicia  126  are marked on the outer surface  120  of the end flanges  44  to indicate the thickness of ceiling covering material that are typically encountered in building construction. The indicia  126  correspond to a given thickness of ceiling covering material. Each row of parallel apertures  122  provides a bend line  124 A,  124 B, or  124 C at which the end flange  44  can be bent outwardly to provide an outward facing seat  128  (see  FIG. 15 ) for properly positioning the electrical box mounting assembly  20  for a given thickness of ceiling cover. For example,  FIG. 14  depicts the installation of the electrical box mounting assembly  20  to two adjacent joists  86  that will be covered with ½″ thick ceiling cover  130 . For positioning the electrical box mounting assembly  20  on joists  86  that will receive a ½″ thick ceiling covering  130 , the end flanges  44  are kept intact and the bottom edge  132  of the end flange  44  (see  FIG. 13 ) is aligned with the bottom of the joists  86 . The bottom edge  52  of the sidewalls  50  of the electrical box  28  extend ½″ below the line  134  connecting the bottom edge  132  of the end flanges  44 . Therefore, positioning the bottom edge  132  of the end flanges  44  level with the bottom of the joists  86  positions the bottom edge  52  of the electrical box  28  level with the lower surface of the ½″ thick ceiling cover  130 , denoted by line  136  in  FIG. 14 . 
   As an alternative example for a different thickness of ceiling cover,  FIG. 15  depicts the installation of the electrical box mounting assembly  20  to two adjacent joists  86  that will be covered with ¾″ thick ceiling cover  130 . For positioning the electrical box mounting assembly  20  on joists  86  that will receive a ¾″ thick ceiling covering  130 , the end flanges  44  are bent outwards at the “A” bend line  124 A. The resulting outward facing seat  128  on each of the end flanges  44  is placed flush against the bottom of each of the joists  86 . Positioning the outward facing seat  128  of the end flanges  44  flush against the bottom of the joists  86  positions the bottom edge  52  of the electrical box  28  level with the lower surface of the ¾″ thick ceiling cover  130 , denoted by line  136  in  FIG. 15 . In a similar manner, bending the end flanges  44  outwardly at the “B” bend line  124 B will position the bottom edge  52  of the electrical box  28  level with a 1″ thick ceiling and bending the end flanges  44  outwardly at the “C” bend line  124 C will position the bottom edge  52  of the electrical box  28  level with a 1″ thick ceiling. The bend lines  124 A,  124 B,  124 C therefore provide a positioning arrangement  140  (see  FIG. 13 ) that allows easy positioning of the electrical box mounting assembly  20  for a given thickness of ceiling cover  130 . 
   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.

Technology Classification (CPC): 8