Abstract:
The objective of the present invention is to provide electrical boxes, electrical mud rings and electrical box extenders with a cheap and efficient way to achieve the correct location of electrical devices with respect to the levels of the walls where they are located. With this electrical screw extender, a mechanical/electrical connection is still safe and lasting too. This electrical screw extender has among its advantages that can be placed in different models of electrical boxes and in mud rings, plus it can be used independently in the already existing constructions to extend the points of connection of devices to the correct levels. Besides, these electrical screw extenders can have different sizes or lengths to suit the different depths of the existing electrical boxes or mud rings, as well as are very comfortable and accurate in their use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of PPA No. 61/713,824, filed Oct. 15, 2012 by the present inventor. EFS ID 13984828 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    None 
       SEQUENCE LISTING 
       [0003]    None 
       BACKGROUND OF THE INVENTION 
       [0004]    This invention relates to an adjustable electrical box screw extender which may be attached to a conventional electrical junction box, a mud ring or can be used alone to enable positioning on the place, where the fixing screws of the electrical devices are inserted, at selectable distances from the junction box or mud ring. 
         [0005]    Because of various state and federal codes, the wiring of a building today requires the use of metal conduits for holding electrical wires, and so-called electrical junction boxes on which may be mounted a variety of electrical switches or plugs for access by the users of the building. Such conduits and junction boxes are mounted within the walls of the building, with openings provided in the walls for access to the junction boxes. These junction boxes are closed on all sides except where joined to conduits and except for the fronts of the boxes which face the openings in the walls. 
         [0006]    It is desirable that the open front of a junction box or the insertion point for the fixing screws of the electrical devices be positioned adjacent to the surface of the wall so that when a switch or plug is mounted in the junction box, the front of the switch or plug will be substantially flush with the surface of the wall. However, because of the wide variety of types of walls in which the conduit and electrical junction boxes are installed, and because the junction boxes are typically installed before the wall surfaces are applied to studs or the like, it is difficult to estimate the proper location of the junction box to ensure that the front of the switch or plug will be flush with the wall surface. If the junction box protrudes out from the wall surface, then the switch or plug will appear unsightly, whereas if the junction box is recessed too far from the wall surface, then the switch or plug to be mounted therein may not be adequately protected from spark or other electrical hazards reaching surrounding combustible materials. Also, if the junction box is too far recessed from the wall surface, it may not even be possible to mount the switch or plug therein. 
         [0007]    A number of adjustable electrical outlet boxes have been proposed to allow mounting a switch or plug so that it is substantially flush with a wall surface. Among these are those disclosed in U.S. Pat. Nos. 1,875,101; 2,048,611; 3,433,886; 4,634,015; 5,098,046; 5,114,105; 5,253,831; 5,289,934; 5,931,325; 6,369,322; 7,002,076; 7,462,775 and 8,245,862. These arrangements all show a combination of a specialized junction box and a slid able element for holding a switch or plug and as such require installation of the specialized junction box everywhere the device is to be used. That is, the device cannot be used with conventional junction boxes and so if the device is going to be used it must be installed at the beginning. This may result in an unnecessary expense since a conventional junction box might have been just as suitable, but such determination is often difficult before the building is constructed. 
       SUMMARY OF THE INVENTION 
       [0008]    The object of the present invention is to provide an adjustable electrical screw extender attachment which may be mounted on a conventional electrical junction box, mud ring or to be used alone and in which may be installed a conventional electrical switch, outlet or any kind of electrical or communication devices. 
         [0009]    It is another object of the invention to provide such electrical screw extender which may be installed after a building wall or other supporting structure is constructed. 
         [0010]    It is another object of the invention to provide electrical box, electrical mud ring and electrical box extender with a system incorporated to accept the assembly of the electrical screw extender. 
         [0011]    It is an additional object of the invention to provide such electrical screw extender in which intimate electrical and mechanical contact is maintained between an installed electrical device and the conventional junction box or mud ring. 
         [0012]    It is a further object of the present invention to provide such electrical screw extender wherein the disposition of the outlet or switch relative to the junction box may be manually adjusted so that the front edge of said outlet or switch can be positioned substantially flush with a wall surface in which said outlet or switch is installed. 
         [0013]    It is a further object of the present invention to provide electrical junction box, electrical mud ring and electrical box extender with an incorporated system to accept the easy assembly of the electrical screw extender. 
         [0014]    It is also an object of the invention to provide such electrical screw extender wherein no fasteners or other implements project into the installed junction box. 
         [0015]    It is also an object of the invention to use only standard bolts sizes, readily available bolts sizes which enable the installer to make use of them. 
         [0016]    It is also an object of the invention to simplify the way of manufacturing and the use of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The above and other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which: 
           [0018]      FIG. 1  is a perspective view of all the system, including the electrical box, the mud ring, the electrical screw extender and the electrical box extender. 
           [0019]      FIG. 2  is a perspective view of an electrical screw extender and how the fixed portion of said electrical screw extender is placed inside a 2 gang electrical box. 
           [0020]      FIG. 3  is a perspective view of an electrical screw extender and how the fixed portion of said electrical screw extender is placed inside a 2 gang mud ring. 
           [0021]      FIG. 4  is a perspective view of a 2 gang electrical box extender with a circular plastic duct to mount said electrical box extender at the electrical screw extender. 
           [0022]      FIG. 5  is a perspective view of an electrical screw extender and its fixed base. 
           [0023]      FIG. 6  is a lateral view of an electrical screw extender and its fixed base. 
           [0024]      FIG. 7  is a perspective view of an electrical screw extender used with a regular switch. 
           [0025]      FIG. 8  is a top perspective view of a 2 gang electrical box extender. 
           [0026]      FIG. 9  is a front view of a 2 gang electrical box extender. 
           [0027]      FIG. 10  is a perspective view of an electrical screw extender and a regular screw of the electrical devices. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]      FIG. 1  is a perspective view which also shows the system that can be used with the electrical screw extender. First is a 2 gang electrical box  21  with its different knockouts  19 , two treated internally threaded holes  28  and the fixed bases  71  with the internal thread  24  and the covered back  20 . Next we see a mud ring  32  with its flat base  29  and location slots  30 . For guiding hexagonal part  26  of the electrical screw extender, it is desirable that the upper and lower edges of said mud ring  32  must have four displacement openings  31  which enable with a nut driver. Next we see four electrical screw extenders with the external thread  25  and the internal thread  23 , the hexagonal part  26  and the regulation nut  27 . And last we see the two gang electrical box extender  83  with two ducts  82 ; two tabs  86  with two slots  85  and the border  81 . 
         [0029]      FIG. 2  is a perspective view which shows the electrical screw extender used in electrical box  21  with its different knockouts  19  with two internally threaded holes  28  and the covered back  20 . The various component parts of the electrical screw extender and its fixed base  71  are shown where said fixed base  71  is inside and fixed to said electrical box  21 . Said fixed bases  71  are observed with their respective internal threads  24  into which external threads or male screws  25  from electrical screw extender may be located to vary the distance from the final position. In the part of said external thread or male screw  25  of said electrical screw extender, locknuts  27  are observed, which serve as a means of fixing the selected distances. The hexagonal portion  26  of the electrical screw extenders must have a regular size, can be guided with a nut driver and also has at its center a treated internal thread  23  where the screws of any standard electrical devices can be placed. The sizes of these internal threads  23  are the standard 6/32 in the case of USA but they could be of another size in order to standardize the measures to those of regular use in other countries. For convenience so that the electrical screw extender can be used directly on the threads of the devices that mud rings have, external threads or male screws  25  of said electrical screw extender and female screws or internal threads  23  which are in the hexagonal part of this electrical screw extender must be both the same measure and standardized to the countries where they are used. By extension the inner threaded portion  24  which is located on the fixed base  71  also must be of the same measure as 6/32 is in the case of USA. 
         [0030]      FIG. 3  is a perspective view showing a regular mud ring  32  with its flat base  29  and location slots  30 . The internal threads  24  which are on said bases  71  should be spaced such that the separation from that it is located in the upper edge and that it is located in the lower edge is the same as the separation that exists among fixing screws in electrical devices like outlets or switches. Like it happens to the electrical boxes, It is also recommended that in the initial location, the outer edge of hexagonal portion  26  of said electrical screw extender and its internal thread  23  are completely flush with the outer edge of the mud ring  32 , whether all portion of the outer thread or male screw  25  of said electrical screw extender is fully inside the inner thread  24  of the fixed base  22  including the width of the locknut  27 . For guiding hexagonal part  26  of this electrical screw extender, it is desirable that the upper and lower edges of the mud ring  32  have four displacement openings  31  which enable with a nut driver, the proper and flush placement with the walls of said different hexagonal parts  26  of electrical screw extenders. 
         [0031]      FIG. 4  is a perspective view showing a two gang electrical box extender  83  which has two ducts  82  to mount said electrical box extender  83  in the hexagonal part  26  of the electrical screw extender. The tab  86  has a slot  85  to insert the device&#39;s screws in the female thread  23  of the electrical screw extender. Border  81  does not have to be wide because this box extender  83  is not supported by walls. 
         [0032]      FIG. 5  is a perspective view showing the electrical screw extender with all of its parts and the fixed base  71  with its internal thread  24  which is capable of accepting the full length of male external thread  25  of said electrical screw extender. The lower parts of the fixed base  71  must be flat for easy fastening of said fixed part  71  in the electrical box  21  or mud ring  32 . The locknut  27  can be displaced along the length of the outer or male thread  25  of the electrical screw extender. The hexagonal part of the electrical screw extender  26  and its internal thread  23  is capable of accepting the screws of electrical devices like outlets or switches that can be sized smaller than the screw of said electrical device in which case a cut of the length of the fixing screw of electrical devices must be made or it must be replaced by a smaller one or even the electric screw extender manufacturer could provide an appropriately sized screw for the electrical devices. Said hexagonal part  26  can be too circular or any other geometric shape with some slot to be guided with a screwdriver. As previously stated, the length of said electrical screw extender and its hexagonal part can be variable depending on the width of the electrical box or mud ring where they are located. Also if these electrical screw extenders are to be used in existing buildings to provide the appropriate location of electrical devices, they may have different sizes so that they help us measure walls or work circumstances where they can be used. 
         [0033]      FIG. 6  shows a lateral view of the electrical screw extender with its fixed base  71  where the internal thread  24  is located which can accept the outer or male thread  25  of the electrical screw extender. The lock nut  27  is movable over said male or external thread  25  and the hexagonal part  26  has an internal thread  23  which can accept screws from electrical devices. Said hexagonal part  26  can be circular, octagonal or any other geometric shape with some slot to be guided by a screwdriver. 
         [0034]      FIG. 7  shows a side view where an electrical switch  51  can be located properly flush with a new wall of tiles  44  that was located with the adhesive  43  on the sheet rock wall  42 . As usual, the electrical box  21  is fixed on one side in the wood beam  41  and the device mounting bolts  33  are placed into the internal thread  23  of the hexagonal part  26  of the electrical screw extender. The fastening nut  27  is tightened against the fixed base  71  after the portion of the outer or male thread  25  of the electrical screw extender has reached the correct distance in its displacement within the inner thread  24  of said flat base  71 . As an extra safety measure to avoid a possible displacement of the external or male thread  25  of the electrical screw extender on the thread of the locknut  27  and the internal thread  24  of the flat base  71 , said outer or male thread  25  may be damaged by any tool at the exact point that coincides with the outer edge of said security thread  27 . The cables  34  are those normally connected to any electrical switch. 
         [0035]      FIG. 8  is a top perspective view for an electrical box extender  83  with one gang showing the duct  82 , the border  81  the tab  86  with the slot  85 . 
         [0036]      FIG. 9  is a frontal view of the same one gang electrical box extender  83  shown in  FIG. 8  with the same parts like duct  82 , border  81 , tab  86  and the slot  86 . 
         [0037]      FIG. 10  is a perspective view showing the electrical screw extender and its different parts, such as the external or male thread  25 , the lock nut  27 , and the exterior hexagonal part  26  with which the exact location of the electrical screw extender is achieved using a nut driver and the internal thread  23  of said hexagonal part  26 , which is able to accept the screws from electrical devices  33 . As a reminder, in the U.S., thread sizes are 6/32 for screws of electrical devices  33 , too for the male or external thread  25  of the electrical screw extender, for the inner thread  23  of the hexagonal portion  26  of said electrical screw extender and the internal thread  24  of the fixed base  72 , but this measure may be another if we use these electrical screw extenders in other countries. 
         [0038]    It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and, the appended claims are intended to cover such modifications and arrangements.