Abstract:
An electrical box with a snap fit panel including a mounting arrangement. The panel can snap fit against an opening in the sidewall of the electrical box to form an electrical enclosure with an internal mounting arrangement for mounting the electrical box in either new work or old work applications. Providing a mounting arrangement integral with the panel instead of integral with the box provides a significantly larger internal volume than prior art one-piece molded electrical boxes with integral internal mounting arrangements. The internal mounting arrangement provides fasteners internal to the electrical box, thereby enabling retrofitting an old box with no disruption to the surrounding wall.

Description:
This application is a Continuation-In-Part of U.S. patent application Ser. No. 11/287,055 filed Nov. 25, 2005 now U.S. Pat. No. 7,214,875, the entire contents of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to electrical boxes and specifically to an electrical box having an snap-in internal mounting arrangement for simplifying replacement of existing electrical boxes or for installation as a new work box. 
   BACKGROUND OF THE INVENTION 
   With the passage of time it is not uncommon for electrical boxes to become loose from the structures they are mounted to. Frequent attachments of plugs into an electrical outlet over time, for example, can cause the supporting outlet box to become unattached from the structure. The loosened electrical box is then a hazard, as it can cause loosening of wires within the box, electrical shorts, and potentially electrical shocks. 
   When an electrical box becomes loose, a prime consideration in replacing the box is minimizing damage to the surface surrounding the box. Electrical boxes for interior walls therefore must be capable of being easily installed into and secured to the existing wall without causing damage to the surrounding wall surface. 
   Electrical boxes have been developed specifically for the replacement of old electrical boxes, which are typically referred to as “old work” boxes. Prior art boxes of this type are described in U.S. Pat. No. 4,297,525 to Bowden, Jr., U.S. Pat. No. 4,120,473 to Suk, U.S. Pat. No. 5,603,424 to Bordwell et al., and U.S. Pat. No. 5,600,093 to Herth et al. In the above patent to Bowden, Jr., a box is shown which employs threaded mounting screws fastened into pawl arms. The pawl arms include tabs extending therefrom. After the box is inserted in an opening in a wall, tightening on the mounting screws urges the tabs linearly toward the box and eventually secures the box to the wall. Suk discloses a box that works in conjunction with a bracket to tighten against the wall. Bordwell et al. discloses a mounting assembly that includes clip-on securement members that are mountable to the outer sidewalls of an electrical box. Each securement member includes a bracket positioned on an external surface of the sidewall and a brace supported by the bracket. The brace is movable on the bracket so as to clamp the box to the mounting wall. Herth et al. discloses a modular interchangeable electrical work box. The work boxes have insert sheaths for fasteners for attaching the work box to a stud. 
   Although the patents to Bowden, Jr., Suk, and Bordwell et al. disclose electrical boxes for use in old work situations, they all rely on clamping type mechanisms that tighten onto the wall covering of the structure. Unfortunately, the wall covering is typically not a structurally strong portion of the wall. Sheet rock for example is used on interior walls, and is not a high strength material. So although the electrical boxes may clamp onto the wall material, the resulting electrical box is not very strongly attached. 
   The electrical box disclosed in Herth et al. improves the installation by providing fastener insert sheaths and fasteners. The fasteners are driven into the studs of the wall instead of into the wall covering. Although this is an improvement over the prior art boxes that employ clamping members, as a result of providing the fastener insert sheaths, the one-piece box disclosed by Herth et al. loses a large portion of the internal volume of the box. Therefore, although the box provides a better connection to the wall, the resulting volume within the box is small and provides inadequate space for completing wiring connections within the box. 
   An improved electrical box for retrofitting on finished walls or for use in new construction was disclosed in co-pending U.S. application Ser. No. 11/287,055, incorporated herein in its entirety and commonly owned by the assignee of the present invention, which included an internal mounting arrangement that was integral with a separate insert portion of the electrical box. By providing the internal mounting arrangement on a separate insert portion, the mounting arrangement is not formed as an integral portion of the box thereby taking up a large amount of otherwise usable volume in the electrical box. 
   The present invention expands upon the advantages of the electrical box of co-pending U.S. application Ser. No. 11/287,055 by providing a box that can be mounted horizontally and includes a mounting arrangement which is formed on a separate panel and then snap fit to the box to provide an internal mounting arrangement for the electrical box. By providing the mounting arrangement on a separate panel, more usable volume is provided within the box. 
   SUMMARY OF THE INVENTION 
   The invention is an electrical box with a snap fit panel containing a mounting arrangement. The panel can snap fit against an opening in the sidewall of the electrical box to form an electrical enclosure with an internal mounting arrangement for mounting the electrical box in either new work or old work applications. Providing a mounting arrangement integral with the panel instead of integral with the box provides a significantly larger internal volume than prior art one-piece molded electrical boxes with integral internal mounting arrangements. 
   OBJECTS AND ADVANTAGES 
   A first advantage of the electrical box of the present invention is that it mounts to a structurally sound portion of a building structure, such as a framing stud, rather than clamping to the wall covering as is presently the case with prior art boxes that rely upon clamping members. 
   Another advantage provided by the electrical box of the present invention is that the mounting arrangement is integral with a separate insert portion of the electrical box rather than with the box itself. As a result, the fastener receptacles formed integral with the insert do not take up a great amount of usable volume within the box, as is the case with prior art boxes in which fastener receptacles are formed integral with the box. Prior art boxes are typically molded in one piece, with the fastener receptacles internal to the box. Molding a box in one piece eliminates a large amount of internal volume and makes it impossible to fit a large electrical component, such as a ground fault receptacle, within the resulting box. The two-piece electrical box of the present invention provides a large internal volume with ample space for bulky devices such as ground fault receptacles. 
   A further advantage of the electrical box of the present invention is that the entire internal mounting arrangement is enclosed within the confines of the internal enclosure. No portion of the mounting arrangement extends beyond the front edge of the enclosure. 
   Another significant advantage is that an appropriate tool can easily reach the mounting arrangement, without any interference from the sidewalls or other portions of the box. A tool, such as a screwdriver, can be aligned with the axis of the fasteners and used to drive the fasteners therein without any interfering contact with the sidewalls of the 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 an exploded perspective view of a preferred embodiment of an electrical box according to the present invention including a box member and a panel exploded away from the box and in alignment to be inserted therein. 
       FIG. 1A  is an exploded perspective view similar to  FIG. 1  but from a different vantage point. 
       FIG. 2  is a front view of a preferred embodiment of a box member according to the present invention. 
       FIG. 3  is a sectional view of the box member taken along line  3 - 3   FIG. 2 . 
       FIG. 4  is a side view of the box member taken from line  4 - 4  of  FIG. 2 . 
       FIG. 5  is a sectional view of the box member taken along line  5 - 5  of  FIG. 2 . 
       FIG. 6  is a perspective view of a preferred embodiment of a panel according to the present invention. 
       FIG. 7  is a perspective view of the panel similar to  FIG. 6  but from a different vantage point. 
       FIG. 8  is an inside view of the panel of  FIG. 6 . 
       FIG. 9  is a sectional view of the panel taken along line  8 - 8  of  FIG. 7 . 
       FIG. 10  is an outside view of the panel of  FIG. 6 . 
       FIG. 11  is a perspective view of a the electrical box of the present invention with the panels inserted therein and in alignment with a framing member prior to being fastened thereto. 
       FIG. 12  is a sectional view of the electrical box assembly of the present invention. 
       FIG. 13  is a sectional view of the electrical box assembly of the present invention secured to a framing member. 
   

   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 
             
             
               22 
               box member 
             
             
               24 
               panel 
             
             
               26 
               sidewall 
             
             
               28 
               inner surface of sidewall 
             
             
               30 
               enclosure 
             
             
               32 
               back wall 
             
             
               34 
               removable wall portion 
             
             
               36 
               first removable portion 
             
             
               38 
               second removable portion 
             
             
               40 
               front edge of sidewalls 
             
             
               42 
               post 
             
             
               43 
               electrical contact point 
             
             
               44 
               first sidewall 
             
             
               46 
               opening 
             
             
               50 
               first rail 
             
             
               52 
               first side of openings 
             
             
               54 
               second rail 
             
             
               56 
               second side of openings 
             
             
               58 
               channel 
             
             
               60 
               planar front edge of first opening 
             
             
               62 
               second sidewall 
             
             
               64 
               recessed area 
             
             
               66 
               knockout portion 
             
             
               67 
               stop 
             
             
               68 
               front edge of panel 
             
             
               70 
               inner surface of panel 
             
             
               72 
               outer surface of panel 
             
             
               74 
               boss 
             
             
               76 
               bore 
             
             
               78 
               edge of panel 
             
             
               80 
               lip 
             
             
               82 
               tab 
             
             
               86 
               front edge of framing member 
             
             
               88 
               framing member 
             
             
               89 
               locking arrangement 
             
             
               90 
               fastener 
             
             
               92 
               fastener axis 
             
             
               94 
               sheet rock 
             
             
               96 
               wall surface 
             
             
               98 
               internal mounting arrangement 
             
             
               θ 
               angle of bore with respect to sidewall of box 
             
             
               D 
               distance of boss from the front edge of the box 
             
             
               O1 
               offset distance of stop from front edge of box 
             
             
                 
             
           
        
       
     
   
   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to a preferred embodiment in  FIG. 1 , the present invention is an electrical box  20  comprised of a box member  22  and a snap fit panel  24  for securing an electrical device such as a duplex outlet (not shown) or similar electrical device in a wall. The electrical box  20  is shown in  FIG. 1  with the panel  24  in alignment with the box member  22  and in alignment to be snapped thereto. The box member  22  includes sidewalls  26  having inner surfaces  28  and defining an enclosure  30  therein. 
   Referring to  FIG. 2  there is shown a preferred embodiment of a box member  22  according to the present invention. The box member  22  includes a back wall  32  and a removable wall portion  34  including a first removable portion  36  and a second removable portion  38 . The first removable wall portion  36  is of a smaller diameter than the second removable wall portion  38 . One or both of the removable wall portions  34  and  36  can be selectively removed to later accommodate different sizes of electrical fittings (not shown) for connecting wiring to the interior of the box member  22 . The sidewalls  26  include a front edge  40  and integral posts  42  extending from the front edge  40  along two of the sidewalls  26  to the back wall  32  of the box member  22 . The posts  42  include bores or electrical component contact points  43  capable of receiving fasteners of an electrical device (not shown) therein. 
   With reference to  FIGS. 2 and 3 , the box member  22  includes a first sidewall  44  that is adapted to receive the snap fit panel  24  (see  FIG. 1 ). The first sidewall  44  includes an opening  46  therein. A first rail  50  extends along a first side  52  of the opening  46  and a second rail  54  extends along a second side  56  of the opening  46 . The first 50 and second 54 rails define a channel  58  (see  FIG. 2 ) in the box member  22  formed between the rails and the first sidewall  44 . The opening  46  includes a planar front edge  60  as shown. 
   As shown in  FIGS. 4 and 5 , the box member  22  includes a second sidewall  62  opposite the first sidewall  44 . The second sidewall  62  includes a recessed area  64  including a knockout portion  66  therein. The recessed area  64  enables connection of fittings, such as the Black Button™ fitting available from Arlington Industries, Inc., of Scranton, Pa., within the knockout  66 . The recessed area  64  enables the fitting to be connected to the second sidewall  62  of the box member  22  without extending beyond the outer surface of the sidewall. The outer surface of the box member  22  also includes integral stops  67  extending from the first sidewall  44  near the front edge  40  of the box member  22 . 
   With reference to  FIGS. 6-10 , a preferred embodiment of the panel  24  includes a front edge  68 , an inner surface  70  and an outer surface  72 , and a boss  74  extending from the inner surface  70 . The boss  74  includes a bore  76  therein and is situated a distance D from the front edge  68  of the panel  24 . The panel  24  further includes edges  78 , a lip  80  extending along each of the edges  78 , and an outward extending tab  82  on the outer surface  72 . 
   As shown in  FIG. 11 , the stops  67  extending from the first sidewall  44  of the box member  22  enable rapid alignment with the front edge  86  of a framing member  88  and position the front edge  40  of the box member  22  at a predetermined offset from the front edge  86  of the framing member  88 . The length of the stop  67  determines the amount of offset and is preferably 0.5 inch to allow for ½″ thick sheet rock to be applied to the framing member  88 . The offset ensures that the front edge  40  of the box member  22  will be substantially even with the outer face of the sheet rock (not shown). 
   Referring to  FIG. 1 , the edges  78  of the panel  24  are snap fit into the channel  58  of the box member  22  by sliding the panel  24  into the channel  58  defined by the rails  50  and  54  that are integral with the first sidewall  44  of the box member  22 . 
   As shown in  FIG. 1A , when the panel  24  is fully advanced into the channel  58 , the outward extending tab  82  of the panel  24  snap fits into the opening  46  of the first sidewall  44  and locks against the planar front edge  60  of the opening  46 . The channel  58  and opening  46  of the box member  22  and the tab  82  on the panel  24  thereby form a locking arrangement  89  for snap fitting and locking the panel  24  to the box member  22 . 
   After the panel  24  is snap fit into the channel  58 , as shown in  FIG. 12 , the opening  46  of the box member  22  is in alignment with the bore  76  of the boss  74  on panel  24 . A fastener  90  is inserted partially within boss  74  and is frictionally held therein. The distance D of the bore  76  from the front edge  40  of the box member  22  and the angle θ of the bore  76  with respect to the sidewall  26  aligns axis  92  of the fastener  90  clear of the sidewalls  26  and the front edge  40  of the box member  22 . As a result of the distance D of the bore  76  from the front edge  40  and the angle θ of the bore  76  with respect to the sidewalls  26 , the axis  92  of the fastener  90  is clear of interference from the sidewalls  26  and the fastener  90  is easily accessible with an appropriate tightening tool such as a screwdriver (not shown). 
   The horizontal electrical box  20  of the present invention is provided in an assembled state, as shown in  FIG. 12 , with the panel  24  locked into the channel  58  of the box member  22  and the fastener  90  secured partially in the boss  74  but not extending beyond the outer surface of the sidewall  26 . The fasteners  90  are therefore provided as captive fasteners, which are available to the installer at the time they are needed for installation. By providing captive fasteners  90  with the electrical box  20  the installer is saved the trouble of finding appropriate fasteners of the correct size and load bearing strength for supporting the electrical box  20 . 
   In a preferred embodiment of the electrical box  20  as shown in  FIG. 12 , the angle θ of the bore  76  with respect to the sidewall  26  of the box member  22  is preferably between 45 and 55 degrees. Most preferably, the angle θ of the bore  76  with respect to the sidewall  26  of the box member  22  is 50 degrees. 
   For operation of the present invention, reference is made to  FIG. 13 . The electrical box assembly  20  is first aligned with a framing member  88  by sliding the electrical box  20  until the stops  67  are flush with the front edge  86  of the framing member  88 . This provides the proper offset distance O 1  to accommodate a layer of sheet rock  94  to form the wall surface  96 . The captive fasteners  90  can then be easily accessed by a conventional tool such as a screwdriver (not shown) and tightened to secure the box member  22  to the framing member  88 . With the fastener  90  tightened completely into the framing member  88  as shown in  FIG. 13 , the electrical box assembly  20  is secure to the framing member  88  and the fastener  90  further locks the panel  24  to the box member  22 . Thus, after tightening the fastener  90  through the opening  46  of the box member  22 , the box member  22  and the panel  24  are locked together by the fastener  90  in addition to the snap fit of the tab  82  within the opening  46 . The boss  74  integral with and extending from the inner surface  70  of the panel  24  and the fastener  90  partially inserted and frictionally held within the boss  74  thereby form an internal mounting arrangement  98  for securing the panel  24  to the box member  22  and framing member  88 . 
   With reference to  FIG. 1 , the box member  22  of the present invention is preferably molded of plastic or formed of metal in one piece. The panel  24  is also preferably molded of plastic or formed of metal in one piece. Plastics suitable for forming the box member and panel include polyvinyl chloride or polycarbonate. 
   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.