Abstract:
A multi-piece structure for mounting an electrical fixture to the side of a building. The structure includes an electrical box having four side walls and locating supports extending radially from said side wall. This fits within the inside of a mounting block with an intermediate plate between the front wall of the mounting block and the opening surface of the electrical box. The electrical box and plate can be formed from fire resistant material permitting the mounting block to be formed from a non-fire rated material. A metal plate can be positioned over the mounting block to provide the appearance of a brass structure. The structure includes two pairs of mounting holes permitting one to attach light fixtures or electrical outlets.

Description:
BACKGROUND  
         [0001]    The use of lapped siding, i.e., vinyl, aluminum, etc., on buildings increases the difficulty of mounting electrical fixtures such as light fixtures, electrical outlets and the like to the sides of buildings. A product was developed which provided a mounting surface for the electrical fixture and was easily integrated into siding. This device is disclosed in Vagedes et al., U.S. Pat. No. 4,726,152. This is mounted to the side of a building with or without the use of an electrical box. The problem with this mounting block and similar blocks is that it is not fire resistant. To be fire resistant, a mounting block must be made from a fire resistant plastic and further there must be an electric box attached to the rear surface of a mounting block. Generally mounting blocks are not deep enough for a standard electric box.  
           [0002]    Making the mounting block itself fire resistant significantly increases the cost of the product. One attempted solution to this problem is disclosed in U.S. Pat. No. 6,359,220 which uses a mounting block that has an electrical box that snap fits into the opening. The electrical box made from fire resistant material is attached directly to the electrical fixture. In order to facilitate electrical wires and electrical outlets, the box needs to be significantly deeper making the mounting block somewhat unsightly.  
           [0003]    Plastic mounting blocks generally match the color of the siding. Siding comes in a wide variety of colors. Thus, stocking mounting blocks which match all siding colors is very expensive.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention is premised on the realization that a fire resistant mounting structure for an exterior electrical fixture can be formed from a mounting block having a flange, a front wall and four side walls. A standard opening is provided in the front wall. The interior of the mounting block holds a separate fire resistant electric box that has an opening substantially larger than the opening on the front surface of the mounting block. Interposed between the electric box and the mounting block is a separate fire resistant plate which restricts the opening on the electric box making it correspond in size to the opening in the mounting block. The interposed plate and the electric box are formed from fire resistant material. This combined structure is fire resistant. At the same time this provides more than adequate room for electrical wiring and/or an electrical outlet. The electric box can include four supports that extend from each corner. These supports locate the box and plate in the mounting block.  
           [0005]    Preferably the structure includes a peripheral ring that snaps on to conceal the cut edges of siding.  
           [0006]    Further, in a preferred embodiment, the structure includes a plate which mounts onto the front surface and covers the front surface as well as the peripheral ring. If the plate is metal, it makes the mounting appear to be metal such as brass or the like. Plastic plates can be used to match the color of the siding. Thus, only one color mounting block is required and less expensive cover plates can be used to match the siding color.  
           [0007]    The objects and advantages of the present invention will be further appreciated in light of the following detailed description and drawings in which: 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    [0008]FIG. 1 is a perspective view of the structure of the present invention partially broken away.  
         [0009]    [0009]FIG. 2 is an exploded view of the FIG. 1.  
         [0010]    [0010]FIG. 3 is a perspective view of the electrical box and interposed plate.  
         [0011]    [0011]FIG. 4 is a perspective view of the mounting box covering the interposed plate and the electrical box.  
         [0012]    [0012]FIG. 5 is a perspective view partially broken away depicting a cover plate covering the structure of the present invention.  
         [0013]    [0013]FIG. 6 is a plan view of the electric box used in the present invention.  
         [0014]    [0014]FIG. 7 is a perspective view of an alternate embodiment of the present invention.  
         [0015]    [0015]FIG. 8 is a cross-sectional view of the cover plate taken at lines  8 - 8  of FIG. 5.  
         [0016]    [0016]FIG. 9 is a cross-sectional view of the cover plate taken at lines  9 - 9  of FIG. 7. 
     
    
     DETAILED DESCRIPTION  
       [0017]    As shown in FIGS. 1 and 2, the present invention is a mounting structure  10  for an electrical light fixture, electric outlet or the like (not shown). The mounting structure includes an innermost electric box  12  which is covered by a mounting block  14 . A cover plate  16  is interposed between the electric box  12  and a front wall  18  of the mounting block  14 . This combined structure is attached to a wall  22  of a building as shown in FIG. 1 with siding  24  abutting the side walls  26 ,  27 ,  28  and  29  of mounting block  14 .  
         [0018]    The edges of the siding are then in turn covered with an exterior snap on ring  34 . The entire structure  10  can in turn be covered by a plate  36  as shown in FIG. 5.  
         [0019]    More particularly, the electric box includes four side walls  38 ,  39 ,  40  and  41 , locating supports  44  extend tangentially from each corner  42 . Inwardly extended portions  46 ,  47 ,  48 ,  49  from the side walls support screw holes  55 ,  56 ,  57 ,  58 . These four screw holes in the mounting block  12  are positioned so that they can facilitate mounting of either an electrical light fixture with holes  55  and  57  diagonally spaced (i.e., about 3.5″) or an electrical duplex outlet with vertically spaced holes  56  and  58  (i.e., about 3.3″).  
         [0020]    Back wall  62  of the box includes a punch out  64  for a mechanical wire fastener or alternately a fastening tab  66  to receive electric cable such as Romex brand cable. Each of the inwardly extended portions  46 - 49  includes a boss  68 ( a ), ( b ), ( c ), ( d ) which extend slightly above the forward edge  72  of the electric box  12 . This extends roughly the thickness of plate  16  and therefore is flush with the forward surface  74  of plate  16  when assembled with plate  16  resting on edge  72  of box  12 . Electric box  12  also includes a boss  50  designed to receive a ground screw.  
         [0021]    Plate  16  is sized to cover electric box  12 . Plate  16  further includes a standard sized rectangular opening  76  generally 2″ by 3-½″ and also includes four cut out portions  77   a, b, c, d  adapted to receive the bosses  68  of the extended portions  46 - 49 . Plate  16  is simply positioned over the electric box  12  completely covering the opening of the box  12 . This forms a complete fire resistant electric box. Cut out portions  77   a  and  77   c  are larger than bosses  68   a  and  68   d  providing an open area aligned with open areas in box  12 . This provides clearance for mounting screws for light fixtures and GFI coverplates. The front wall of block  14  has corresponding openings.  
         [0022]    The mounting block  14  in turn has a peripheral flange  78 , extended from side walls  26 - 29 . Front wall  18  includes an opening  79  corresponding in size and shape to the opening  76  in plate  16 . This opening should be about equal to or larger than the opening in plate  16 . The four supports  44  of the electric box  12  engage the internal surface of the four corners  80  of block  14  aligning all these elements and provide a wedge fit.  
         [0023]    Ring  34  which snap fits over block  14  has an internal surface  82  corresponding to the four walls  27 - 30  of the mounting block  14 . It includes first and second tabs  84  (only left side showing) which are adapted to snap into first and second indentations  88 ,  90  in the side walls  27  and  29  of the mounting block  14 . This ring  34  simply covers the exterior edges of siding once the unit  10  is installed.  
         [0024]    To install the unit of the present invention, a wire  92  is attached to the electric box  12  either through the opening at tab  66  or with an electrical connector through knockout  64 . The plate  16  is then placed over the electric box  12  and the mounting block  14  is placed over the combined electric box  12  and plate  16 . The supports  44  will properly locate the box  12  within the mounting block  14  to center the screw holes  58  in the box  12  with the openings  77  in plate  16  in the front wall  18  of the mounting block  14 . The wall flange of block  14  is nailed to the exterior wall  22  of a building. This holds the electric box  12  and plate  16  compressed between the wall  22  and front wall  18  of block  14 . Siding  24  is attached to the building abutting the four walls of the mounting block  14 . Ring  34  is snap fitted onto the side walls  27  and  30  of the mounting block  14 . The top of ring  34  is flush with the front wall  18  of the mounting block  14 .  
         [0025]    An electrical fixture (not shown) can then be attached to the wire  92  in the electric box  12  and screwed onto box  12  using holes  56  and  58  or  55  and  57 . Depending on the type of fixture, the open area above and below mounting holes  56  and  58  will provide clearance for fixture mounting screws. This combination of two sets of holes and the open areas above and below holes  56  and  58  permits most light fixtures, switches and outlets to be mounted.  
         [0026]    A cover plate  36  can be employed to cover the entire mounting structure  10  positioned between structure  10  and the electric fixture and provide a unique appearance. As shown in FIG. 5, plate  36  covers the entire front surface of wall  18  and extends beyond the edge of the mounting block  12  and the ring  34 . As shown in FIG. 8, the opening  91  in plate  36  has an inwardly extended lip  92  which centers the plate with opening  79  in block  14 . This will in turn be held in position permanently when an electrical fixture is attached to the box by screws or bolts extending from the electrical fixture into the screw holes  56  and  58  or  55  and  57 . Alternately as shown in FIG. 9, metal or plastic tabs  93  can be used to center the plate  36 ( a ). The plate can also be centered by its lower surface corresponding in size and shape to the ring  34 . Optionally centering tabs or posts (not shown) can extend from the backside of plate  36  and fit into corresponding openings in the front wall  18  of block  14 . These can provide an interference fit to temporarily hold the plate in place.  
         [0027]    This cover plate  36  can be used with or without the ring  34  and can be used with any plastic mounting block as long as the plate has a dimension which extends beyond the side walls of the mounting block  12 . Thus, it can be used to retrofit existing mounting blocks. Plate  36  can be plastic, metal, or metal coated plastic. Further, it can be square rectangular or oval, i.e., nonrectangular. It can be significantly larger than the block and used to mount a coach fixture, i.e., where the fixture is larger than the block.  
         [0028]    As indicated, the electric box  12  and plate  16  are preferably made from a fire resistant plastic or metal suitable for an exterior building. Their color is not relevant as they will be totally concealed by the mounting block  14  and any electrical fixture. The block  14  and ring  34  can then be formed from a different non-fire rated plastic. This reduces the cost of structure  10  while maintaining overall fire resistance. The color of the block  14  and ring  34  should match or accent the siding  24 .  
         [0029]    The present invention provides a mounting structure for an electrical fixture which is fire resistant whereas the mounting block  14  itself does not need to be made from fire resistant material. The inner electrical box  12  and intermediate plate  16  provides the fire resistant structure. Changing the color of the block will not affect the fire rating of the product. This encases the electrical wiring within a fire resistant structure making it compliant with current electrical codes. Further, due to the use of the intermediate plate, an electrical box can be molded or stamped to provide a large space for wiring without the need for an unsightly deep mounting block. The permanent locating supports on the mounting box ensure that when it is assembled, the opening in the electrical box is properly located within the mounting block and further facilitates quick assembly of the structure. Finally, the metal plate that can be attached to the exterior surface providing a truly unique appearance for the mounting block. Thus, the present invention facilitates easy installation, provides adequate room for electrical wires, provides fire resistance and improves the overall appearance of the mounting block.  
         [0030]    This has been a description of the present invention along with the preferred method of practicing the invention, however, the invention itself should only be defined by the appended claims wherein we claim: