Abstract:
A depth-adjustable electrical box assembly for mounting of a fan or fixture on a ceiling including a fan/fixture box and a depth adjustment screw that is always accessible for adjusting the depth of the electrical box with respect to the ceiling. Bracket mounting screws are held captive with the assembly. A slide plate on the fan/fixture box is slideable with respect to the box. A base plate integral with the slide plate includes apertures therein for accepting the bracket mounting screws. A screw retainer, held securely to the fan/fixture box by a bracket, retains the end of the adjustment with respect to the box. Straps on the slide plate provide threaded engagement with the depth adjustment screw and enables the slide plate to slide with respect to the electrical box in response to rotation of the adjustment screw.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional U.S. application No. 62/156,538, filed May 4, 2015. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to electrical boxes for mounting of fans and ceiling fixtures and specifically to an electrical box that allows depth adjustment of the box after the ceiling is in place. 
     BACKGROUND OF THE INVENTION 
     In the mounting of fans and ceiling fixtures it is typically desired to install the front face of the electrical box substantially flush with the ceiling. Conventional electrical boxes are typically fastened to a joist before the drywall is installed thereto. As drywall is supplied in various thicknesses or at times is doubled up to form a thicker ceiling, it is difficult for the installer to initially position the electrical box at the ideal level for the box to be flush with the eventual ceiling surface. 
     Although some adjustable electrical boxes have been proposed for adjusting the depth of a box at initial installation, there is no accommodation for later adjustment of the box after the initial installation. After initial installation of these prior art boxes, there is no mechanism to enable easy adjustment of the box with respect to the ceiling surface. 
     Accordingly, what is needed therefore is an adjustable electrical box that is capable of being securely fastened to a joist but which enables later adjustment of the depth of the box with respect to the ceiling surface. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is a post-installation depth-adjustable electrical box assembly for mounting of a fan or fixture on a ceiling. The electrical box assembly includes an electrical box or fan/fixture box and a depth adjustment screw that can be accessed at any time after the box is secured to a joist. The depth adjustment screw enables the rim of the box to be adjusted flush with the ceiling surface. Bracket mounting screws are held captive with the assembly. The fan/fixture box includes a bracket that can slide with respect to the box. The depth adjustment screw, accessible from the open face of the fan/fixture box, can be rotated to move the box with respect to a joist to which the fan/fixture box is secured thereby allowing adjustment of the fan/fixture box face so that it is flush with the ceiling surface. A slide plate includes an integral bracket with apertures therein for accepting the bracket mounting screws. A top bracket holds a screw retainer securely to the fan/fixture box and screw retainer retains the end of the adjustment with respect to the fan/fixture box. Straps on the slide plate provide threaded engagement with the depth adjustment screw and enables the slide plate to slide with respect to the fan/fixture box. 
     OBJECTS AND ADVANTAGES 
     A first object of the invention is to provide a depth-adjustable electrical box assembly for mounting of a fan or fixture on a ceiling. 
     A second object of the invention is to provide a depth-adjustable electrical box that may be adjusted after the box is mounted and the drywall has been installed. 
     A further object is to provide a depth-adjustable electrical box including a fan/fixture box and a slide plate that is slideable with respect to the box. 
     Another object is to provide a fan/fixture box and slide plate arrangement that is pre-set for ½″ ceilings and for which the depth may be adjusted up to 1½″. 
     A further object of the invention is to provide a depth-adjustable electrical box with a screw retainer means to retain the end of a depth-adjustment screw and thereby maintain its axis of rotation with respect to the 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. 
    
    
     
       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 a front exploded isometric view of a first and preferred embodiment of a depth-adjustable electrical box, in accordance with embodiments of the invention. 
         FIG. 2  is a top view of an electrical box that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 3  is a bottom view of the electrical box. 
         FIG. 4  is a sectional view of the electrical box taken along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a sectional view of the electrical box taken along line  5 - 5  of  FIG. 2 . 
         FIG. 6  is an isometric view of the electrical box. 
         FIG. 7  is an isometric view of a slide plate that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 8  is an elevation view of the slide plate. 
         FIG. 9  is a sectional view of the slide plate taken along line  9 - 9  of  FIG. 8 . 
         FIG. 10  is an end view of the slide plate as viewed from the top of  FIG. 8 . 
         FIG. 11  is an isometric view of a bracket that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 12  is a plan view of the bracket. 
         FIG. 13  is a side view of the bracket. 
         FIG. 14  is an isometric view of a screw retaining tab that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 15  is a plan view of the screw retaining tab. 
         FIG. 16  is a sectional view of the screw retaining tab taken along line  16 - 16  of  FIG. 15 . 
         FIG. 17  is an isometric view of a box rim plate that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 18  is an isometric view of a depth-adjustment screw that forms a portion of the adjustable fan box of  FIG. 1 . 
         FIG. 19  is an isometric view of the depth-adjustment screw from the opposing end as that shown in  FIG. 8 . 
         FIG. 20  is a top view of the adjustable fan box of  FIG. 1 . 
         FIG. 21  is a bottom view of the adjustable fan box. 
         FIG. 22  is a side view of the adjustable fan box from the side depicting the slide plate. 
         FIG. 23  is a bottom isometric view of the adjustable fan box. 
         FIG. 24  is a top isometric view of the adjustable fan box. 
         FIG. 25  is a front elevation view of the adjustable fan box secured to a joist. 
         FIG. 26  is a side view of the adjustable fan box secured to a joist. 
         FIG. 27  is an isometric view of the adjustable fan box secured to a joist. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , there is shown a preferred embodiment of a depth-adjustable electrical box assembly  30 , in accordance with embodiments of the invention. The depth-adjustable electrical box assembly  30  is an assembly for mounting an electrical fan or electrical fixture, such as a light, to an overhead support (not shown) such as a rafter. The adjustable fan box  30  includes a fan/fixture box or electrical box  32 , a slide plate  34 , a bracket  36 , a screw retaining tab  38 , a box rim plate  40 , one or more device mounting screws  42  for mounting a fan or fixture to the electrical box, bracket mounting screws  44 , and an adjusting screw  46  for adjusting the position of the electrical box  32  with respect to the overhead support. 
     Referring to  FIGS. 2-3 , the electrical box  32  includes an arcuate side wall  48 , a flat side wall  50 , a top wall  52 , an arcuate bottom rim  54  on said arcuate side wall, and a sidewall extension  56  integral with and extending outward from the flat side wall  50 . A notch  58  is provided in the sidewall extension  56  and a recessed area  60  is provided in the top wall  52 . As shown in  FIG. 2 , mounting screw receptacles  62  extend from the top surface of the top wall  52 . 
     Referring to  FIGS. 4-5 , the arcuate side wall  48  includes open channels  64  located 180 degrees apart on the electrical box. A box mounting boss  66  extends across each channel  64  and includes a box mounting bore  68  therein. Mounting screw receptacles  62  each include a bore  70  therein that is accessible from the inner enclosure  72  of the electrical box that is defined by the arcuate side wall  48 , the flat side wall  50 , and the top wall  52 . Sidewall extension  56  includes a boss  74  having an aperture  76  therein and a ledge  78  extending outward from the boss  74 . 
     With reference to  FIG. 6 , the electrical box further preferably includes two bracket alignment posts  80  extending from the top wall  52 , apertures  82  inboard of the bracket alignment posts, and one or more knockout panels  84  that can be removed by an installer to create a knockout  86  for passage of electrical cables into the electrical box  32 . A post  88  extends from the surface  90  surrounding the recess  60  in the top wall. The electrical box further includes two rails  92  at opposing edges  94  of the flat side wall  50 . Rails  92  include a base portion  96  and an end portion  98  that define channels  101 . Two ribs  103  extend from the flat wall  50  and are each located near one of the channels  101 . Notch  58  of sidewall extension  56  includes a substantially U-shaped perimeter  105  and includes a base portion  107  and two outward extending wings  109 . An aperture  110  is provided in each wing  109 . One or more narrowed portions  113  are provided around the perimeter  105  of the notch  58 . 
     Referring to  FIG. 7 , the slide plate  34  includes a base plate  111  including two outturned edges  113 , two wings  115 , and an aperture  117  in each wing. The wings  115  are laterally offset from the plane containing the base plate  111 . Two ribs  119  extending from the base plate  111  each include an outer surface  121  that is offset from the base plate. The base plate  111  includes an inner edge  123  and an outer edge  125 . A nailing flange  127  extends from the central portion of the base plate  111  at the inner edge  123 . Nailing flange  127  includes one or more apertures  129  through which fasteners  130  are driven for securing the depth-adjustable electrical box assembly to a joist  132  (see  FIG. 25 ). Two parallel outturned ribs  131  provide thread engagement surfaces for capturing and engaging threads  133  of adjusting screw  46 . Nailing flange  127  includes an opening  135  therein for enabling the passage of adjusting screw. Nailing flange  127  is preferably at a 90° angle with respect to the base plate  111 . 
     With reference to  FIGS. 11-13  bracket  36  is a substantially planar plate that includes an inner side  137 , an outer side  139 , alignment apertures  141 , box engagement apertures  143 , and fan or fixture apertures  145  therein extending from the inner side to the outer side. The bracket  36  includes a long side  147  and a short side  149  and two opposing slots  151  near the short side  149 . 
     Referring to  FIGS. 14-16 , screw retaining tab  38  includes an inner end  153 , an outer end  155 , an alignment aperture  157 , and a screw retaining aperture  159  therein. Screw retaining tab  38  further includes a first surface  161  and a second surface  163 . 
     With reference to  FIG. 17 , box rim plate  40  includes a flat body  165  having a top surface  167  and a perimeter wall  169 . Perimeter wall  169  and top surface  165  create a recessed area  171  on the top side of the box rim plate. The box rim plate  40  further includes one or more top tabs  173  extending from the top of the perimeter wall  169  and one or more bottom tabs  175  extending from the bottom of the perimeter wall  169 . The top tabs  173  and bottom tabs  175  define a channel  177  there between that function to snap engage the narrowed portions  113  around the perimeter  105  of the notch  58  of the electrical box  32  (see  FIG. 6 ). 
     Referring to  FIG. 18 , an adjusting screw  46  according to the present invention includes a head  179 , a threaded shank  181  including threads thereon, a threadless tip  183 , a collar  185  near the head, the collar  185  extending outward of the threads, and a seat  187  between the head  179  and the collar  185 , the seat being smooth and of smaller diameter than the threaded shank  181 . 
     With reference to  FIG. 1 , the depth-adjustable electrical box assembly  30  is assembled by first sliding slide plate  34  within the channels  101  at the sides of the flat wall  50  of electrical box  32 . Adjusting screw  46  is then passed through boss  74  of electrical box  32  and rotated through the parallel outturned ribs  131  of slide plate  34 . Screw retaining tab  38  is then aligned with electrical box  32  by aligning alignment aperture  157  of screw retaining tab  38  with post  88  of electrical box  32  and slipping the screw retaining tab  38  into recess  60  of electrical box. Bracket  36  is then aligned with top surface  52  of electrical box  32  by fitting alignment posts  80  of electrical box through alignment apertures  141  of bracket  36 . Bracket  36  is secured to top surface  52  of electrical box  32  by tightening bracket mounting screws  44  through apertures  143  of bracket into apertures  82  of electrical box. Once secured to the electrical box  32 , the bracket  36  holds screw retaining tab  38  within the electrical box assembly and slide plate  34  against flat wall  50  and within channels  101  of electrical box. Threadless tip  183  of adjusting screw  46  engages screw retaining aperture  159  of screw retaining tab  38 . The aperture  159 , which could be a bore partially through the screw retaining tab  38 , keeps the adjusting screw  46  in proper axial alignment with the sliding plate  34  and electrical box  32 , and keeps the adjusting screw  46  from being bent out of axial alignment. The depth-adjustable electrical box assembly  30  may then be secured to an overhead support by driving nails, screws, or similar fasteners  186  (through apertures  129  in nailing flange  127  and through apertures  117  in ears of slide plate  34 . Arcuate bottom rim  54  of electrical box  32  can then be adjusted parallel to the desired level with respect to surface of the ceiling (not shown) by turning adjusting screw  46  in the appropriate direction to raise or lower the electrical box with respect to the ceiling. After the electrical box  32  is at the desired level with respect to the ceiling, box rim plate  40  may be snapped into the notch  58  of the electrical box to provide a circular bottom rim  188  on the electrical box and to occlude sight of the slide plate  34  from the bottom of the assembly. If further adjustment of the level of the electrical box  32  with respect to the ceiling is required at a later date, the adjusting screw  46  is accessible from the bottom of the adjustable fan box assembly  30 . 
     With reference to  FIG. 20 , the adjustable fan box assembly  30  includes bracket mounting screws  44  securing bracket  36  and screw retaining tab  38  to the electrical box  32 . As shown in  FIG. 21 , the adjusting screw  46  is accessible from the bottom of the adjustable fan box assembly  30 . 
     Referring to  FIG. 22 , clockwise rotation of adjusting screw  46  will raise the level of the electrical box  32  with respect to the ceiling and counterclockwise rotation of adjusting screw  46  will lower the level of the electrical box  32  with respect to the ceiling. 
     The electrical box assembly  30  is provided as an assembly as shown in  FIG. 23 . The device mounting screws  42  are captively held within the electrical box assembly  30  within the bores  70  of mounting screw receptacles  62  (see  FIG. 5 ). The mounting screw receptacles  62  hold the mounting screws  42  during storage and shipment. At the jobsite, after the electrical box assembly  30  is secured to an overhead support, the installer removes the mounting screws  42  from the screw receptacles  62  and uses them to mount a fan or fixture (not shown) to the support through bores  68  of box mounting bosses  66 . Preferably the bottom surface of the box rim plate  40  is flush with the sidewall extension  56  and the rim  54 . The head  179  of the adjusting screw  46  is recessed below the level of the sidewall extension  56  and the box rim plate  40 . 
     In the embodiment shown herein, the depth-adjustable electrical box assembly  30  is capable of supporting a fan of up to 70 pounds and a fixture of up to 100 pounds. Bracket  36  and screw retaining tab  38  are each preferably constructed of galvanized steel and each include a thickness of at least 0.125 inch. Sliding plate  34  preferably is constructed of galvanized steel and includes a thickness of at least 0.062 inch. 
     With reference to  FIG. 24 , one or more of the knockout panels  84  may be removed from the top wall  52  of the electrical box  32  and an electrical fitting  189  may be fitted within the resultant knockout  86  (see  FIG. 6 ) in the top wall of the electrical box  32 . One such electrical fitting  189  may be 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 will enable push-in connection of a non-metallic cable (not shown) to the electrical box  32 . 
     Electrical box  32  may be formed of metal or plastic. Most preferably electrical box  32  is molded in one piece of plastic. Suitable plastics include such as polycarbonate or polyvinyl chloride. Serrations  191  are preferably included under the head  193  of the device mounting screws  42  to lessen the chance of unintended loosening of the screws while they are supporting a rotating fan or a stationary fixture. As shown in  FIG. 24 , mounting screws  42  preferably are long enough to extend from the arcuate bottom rim  54  through channel  64  and completely through apertures  145  in thick bracket  36 . 
     With reference to  FIGS. 25-27 , the depth-adjustable electrical box assembly  30  is shown secured to a joist  132 . The assembly is secured to the joist  132  by fasteners  186  driven through wings  115  of slide plate  34  and fasteners  130  driven through nailing flange  127  of slide plate. For mounting of an electrical device (not shown), such as a fan or light fixture, to the electrical box assembly  30 , mounting screws  42  are removed from captive storage in mounting screw receptacles  62  (see  FIG. 26 ) and inserted through box mounting boss  66  of electrical box  32  and into apertures  145  in bracket  36  to secure the device to the assembly. The adjusting screw  46  is accessible from the bottom of the assembly  30  after being secured to the joist  132 . The assembly  30  is thus a post-installation depth-adjustable electrical box assembly for mounting of a fan or fixture on a ceiling. The meaning of post-installation as used herein is that the depth of the electrical box assembly can be adjusted at any time after being secured to the joist, as the head of the adjusting screw is accessible from the bottom of the assembly. 
     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.