Abstract:
A pan box assembly for fixtures for use on exterior walls. The box assembly includes a base unit, which is mounted directly to a flat surface substrate, and two extension elements. The unit, along with the extension elements, allows for modification of certain dimensions of the box assembly so that it can be used with three different finish thicknesses. The extension elements may be added or removed without uninstalling the box or removing the back of the box.

Description:
FIELD OF THE INVENTION 
     The present invention relates to assemblies for the mounting of electrical devices and fixtures, and, more specifically, to electrical box assemblies which are typically installed and utilized in the exterior walls of buildings and other structures. 
     BACKGROUND OF THE INVENTION 
     A common goal in installing electrical boxes for fixtures in exterior walls, particularly those having a stucco finish, is to install the face of the box substantially flush with the exterior wall surface. 
     Stucco is frequently applied to exterior walls in order to create a decorative but durable coating. The depth of the stucco application is typically defined by an architectural stucco reveal system. The stucco reveal system typically includes interconnecting strips of material, or reveals, which are attached to an underlying substrate. The reveals provide a screed edge which will define the location of the face surface of the stucco and thus the depth of the stucco. The reveals are usually provided in several standard sizes in order to form a desired stucco depth. Typically, stucco applications are completed in one of three particular thicknesses, i.e., 1⅜ inch, ⅞ inch, and ⅝ inch. 
     As a result of the various conventional depths of stucco applications on exterior walls, several sizes of electrical boxes are required at the job site in order to insure that the electrical box is flush with the wall finish. It is therefore desirable to have a single electrical box assembly that can be configured at the job site to match the installed reveal and thereby mount the electrical box flush with the stucco surface. 
     OBJECT OF THE INVENTION 
     It is a goal of the invention to provide a fixture box that mounts directly to a flat surface to be used on exterior walls such that it is able to sit essentially flush with the finished coating on such walls. 
     It is a further goal of the invention to provide a fixture box with interchangeable extension elements so as to permit the box to be used on exterior walls having varying finish thicknesses. More specifically, it is an object of the invention to provide an electrical box assembly which facilitates the mounting of electrical fixtures in applications having any of three different finish thicknesses and, therefore, requiring one of three different reveals. 
     It is another goal to provide a pan box which is mountable directly on the flat surface of a substrate so as to avoid the need to cut large holes in the substrate. 
     It is a further goal to minimize the cost of the box assembly by constructing it of a minimal number of parts. 
     SUMMARY OF THE INVENTION 
     The present invention describes an electrical box assembly for the installation of fixtures on exterior wall surfaces having varying finish thicknesses. The box assembly mounts directly to the flat-surface substrate and alleviates the need to cut large holes in the substrate for installation. The box assembly can be used by itself or with one of two extension rings, thereby insuring that the box provides the desired reveal when used in conjunction with any of three wall finish thicknesses, namely 1⅜″, ⅞″, and ⅝″ finishes. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of the pan box assembly disclosed herein. 
         FIG. 2  is a front view of the pan box assembly disclosed herein. 
         FIG. 3  is a rear view of the pan box assembly disclosed herein. 
         FIG. 4  is a side view of the pan box assembly disclosed herein. 
         FIG. 5  is a sectional side view of the pan box assembly disclosed herein. 
         FIG. 6  is a perspective view of the pan box assembly disclosed herein. 
         FIG. 7  is an exploded side view of the pan box assembly including a first extension element. 
         FIG. 8  is an exploded side view of the pan box assembly including a second extension element. 
         FIG. 9  is a side view of the pan box assembly including a first extension element. 
         FIG. 10  is a side view of the pan box assembly including a second extension element. 
         FIG. 11  is a perspective view of the base unit along with the extension elements. 
     
    
    
     TABLE OF NOMENCLATURE AND PARTS 
     The following is a listing of the nomenclature and parts, along with accompanying reference numerals, that are used to describe the invention set forth herein: 
     
       
         
               
               
             
           
               
                   
               
               
                 Part Number 
                 Brief Description 
               
               
                   
               
             
             
               
                 100 
                 Electrical box assembly 
               
               
                 105 
                 Base unit 
               
               
                 110 
                 First extension element 
               
               
                 115 
                 Second extension element 
               
               
                 120 
                 Base plate 
               
               
                 125 
                 Side wall 
               
               
                 130 
                 Interior space 
               
               
                 150 
                 Apertures 
               
               
                 155 
                 Boss 
               
               
                 160 
                 Bore 
               
               
                 165 
                 Fastener 
               
               
                 170 
                 Fastener 
               
               
                 172 
                 Base of Fixture 
               
               
                 175 
                 Grounding boss 
               
               
                 185 
                 Mounting section 
               
               
                 190 
                 Knockout portions 
               
               
                 200 
                 Depression 
               
               
                 210 
                 Extension element boss 
               
               
                 215 
                 Extension element bore 
               
               
                 220 
                 Extension element grounding boss 
               
               
                 225 
                 Extension element grounding boss bore 
               
               
                 230 
                 Lip 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a first embodiment of the electrical pan box assembly  100  disclosed herein. The pan box assembly  100  includes a base unit  105 , a first extension element  110  (shown in  FIG. 1 ), and a second extension element  115  (shown in  FIGS. 10 and 11 ). The base unit  105  includes a base plate  120  which is generally quadrilateral in shape and has a front section and a rear section. In the preferred embodiment shown in  FIG. 1 , the base plate  120  is of a substantially square shape. A sidewall  125  extends outward from the front section of the base plate  120 . The sidewall  125  defines an interior space  130  being bounded on one end by the base plate  120  and being open to the exterior on the other end. The base plate  120  includes apertures  150  therein. The apertures  150  are capable of receiving fasteners (not shown) which pass through the base plate  120  and terminate in or beyond the mounting substrate (not shown). 
     As seen in  FIGS. 1 and 2 , one or more bosses  155  are integral with the sidewall  125  and extend into the interior space  130 . These bosses  155  may contact or originate from the base plate  120  but they need not do so. The bosses  155  include bores  160  therein.  FIG. 5  is a cross-sectional view of the base unit  105  including the bosses and bores therein. The bores are directed toward the front end and are disposed to receive fasteners  165  for securing first extension unit  110  to base unit  105  and fasteners  170  for securing base  172  of fixture (not shown) to first extension unit  110 . The preferred embodiment includes four bosses  155 , namely, two mounting bosses (for mounting either of said optional spacers  110 ,  115 ) and two fastening bosses (for fastening an electrical device within said assembly  100 ). In this embodiment shown in  FIG. 2 , a mounting boss and a fastening boss are located at a first position on the sidewall  125  and a second mounting boss and fastening boss are located on a second, opposed position on the sidewall  125 . The assembly  100  also includes a grounding boss  175  which is integral with the sidewalls  125  of the base plate  120 . The grounding boss  175  further includes a bore  180  directed toward the front section and capable of receiving a grounding screw (not shown). 
     Referring to  FIG. 2 , the base plate  120  includes one or more mounting sections  185  that are on the portion of the base plate  120  enclosed by the sidewall  125 . The mounting portion  185  includes one or more knockout portions  190  capable of being removed in order to provide a passageway for electrical cable or wire into or through the interior space  130 . The mounting portion  185  is raised in any location where a knockout portion  190  is found; that is, the knockout portions  190  are mounted on mounting sections  185  of the base plate  120  which project slightly into the interior space  130 . There is a corresponding depression  200  on the opposite side of the base plate  120 , as shown in  FIG. 3 . 
     The first extension element  110  is a ring, being cylindrical in nature with peripheral sidewalls and possessing a hollow center as shown in  FIG. 11 . The ring is of a circumference substantially identical to that of the base unit sidewall  125  and of a pre-determined depth D 2 . The extension ring possesses a front side and a rear side both of which terminate in a planar face. Referring back to  FIG. 1 , the ring includes one or more bosses  210  integral with the ring  110  and extending into the interior space of the ring. The bosses include bores  215  therein which run through the length of the boss, resulting in an opening on both ends of the boss  210 ; the bores  215  are co-axial with corresponding bores in the base unit  105  in order to accomplish mounting of the spacer and an electrical device to the base unit  105 . 
     Referring now to  FIG. 2 , the first extension element  110  also includes a grounding boss  220  which is integral with the body of the element  110 . The grounding boss  220  includes a bore  225  therein which runs through the length of the boss  220  resulting in an opening on both ends of the grounding boss  220 . Finally, the extension ring  110  includes a lip or flange  230  which extends outward from the rear side and circumscribes at least a portion of the ring. In the preferred embodiment shown in  FIG. 1 , the lip  230  circumscribes the entire portion of the rear side of the ring with the exception of a first break  235  and a second break  240 . As noted above, the bosses  210  are positioned such that the bores in these bosses  215  may be axially aligned with the bores  160  in the bosses  155  of the base unit  105  and, further, and the grounding bosses  220  is positioned such that the bore  225  in the grounding boss  220  may be axially aligned with the bore  180  in the grounding boss  175  of the base unit  105 . 
     The second extension element  115  is a ring, being cylindrical in nature and possessing a hollow center. The ring is of a circumference substantially identical to that of the sidewall  125  and of a pre-determined depth D 3 . Aside from the difference in depth, the second extension element  115  is identical to the first extension element  110  and includes the same elements in the same orientation. It will be noted that in the preferred embodiment D 2  is equal to a value of ¾″ and D 3  is equal to a value of ¼″. 
     In operation, a user first determines the desired reveal. The pan box assembly  100  may be distributed pre-assembled in any of the three thickness configurations. In a preferred embodiment, the pan box is pre-assembled to be used with 1⅜″ wall finish thicknesses as seen in  FIG. 1 . Referring now to  FIGS. 1 ,  7  and  9 , the pan box configuration suitable for 1⅜″ cladding use comprises the base unit  105  with the first extension element  110  attached thereto. The first extension element  110  is removably secured to the base unit  105  via one or more fasteners  165  which pass through the bosses of the first extension element  110  and into the bosses  155  of the base unit  105 . The lip  230  is seated in the interior space  130  and abuts the sidewall  125 . The lip  230  includes breaks or spaces  235 ,  240  in the locations where the bosses and bores of the sidewall  125  and the extension element  110  are co-axial, as seen in  FIG. 1 . The lip  230  assists the user in properly aligning the base unit  105  and the extension element and, once aligned and seated, serves to prevent travel of the extension element  110 . 
     Once the cladding thickness is determined and the pan box assembly  100  is configured for such thickness, the user drills or otherwise creates a hole for the electrical wire or cable. It will be noted that when using this pan box assembly, the hole need only be large enough to accommodate the wire or cable and there is no need to cut or make a large hole in the substrate. Once the wire or cable is pulled through, the pan box assembly is installed to the substrate though the use of fasteners passing though the apertures  150  in the base plate  120 . 
     The pan box assembly  100  is easily adapted for use with two other finish thicknesses. In order to use the pan box assembly  100  in a ⅝″ cladding application, the base unit  105  is used without any extension elements as seen in  FIG. 6 . The base unit  105  is mounted to the substrate and no extension rings are attached to the base unit. Referring now to  FIGS. 8 and 10 , in order to use the pan box assembly  100  in a ⅞″ cladding application, the base unit  105  is used with the second extension element  115 . The base unit  105  is mounted to the substrate and the second extension ring  115  is secured in the same fashion as the first extension element  110 . Accordingly, the pan box assembly is suitable for 1⅜″ cladding by using the base unit  105  and the first extension element  110 , suitable for ⅝″ cladding by removing all extension elements and using the base unit  105  alone, and suitable for ⅞″ cladding by using the base unit and the second extension element  115 . The desired reveal can therefore be changed or altered without uninstalling or removing the base unit, rather, the reveal can be modified by simply adding or removing the extension elements  110 ,  115 . 
     The base unit  105  and optional extension spacer elements  110 ,  115  allow one box to work with the most commonly found exterior wall finishes. The invention alleviates the need to stock multiple boxes for multiple finishing thicknesses. Further, as the pan box is mounted directly on a flat surface, there is no need to cut a large hole in the substrate to mount the assembly. The extra-wide base plate  120  prevents water and air intrusion between the flange and stucco; no gaskets or caulking are required. Moreover, the knockout mounting sections  185  are raised such that adaptor rings or other connectors may be installed in the knockout opening without causing the assembly to extend beyond the plane of the base plate  120 . 
     In a preferred embodiment, the electrical box assembly  100  is composed of a non-metallic thermoplastic material such as polypropylene, polyethylene, polyvinyl chloride, polycarbonate, or acrylonitrile butadiene styrene. The use of these materials assures that the device box assembly  100  possesses appropriate non-corrosive and non-conductive properties. This construction further assures that the assembly  100  is compatible with most building surfaces. 
     While the invention has been described in reference to certain preferred embodiments, it will be readily apparent to one of ordinary skill in the art that certain modifications or variations may be made to the system without departing from the scope of the invention claimed below and described in the foregoing specification.