Abstract:
An adjustable template assembly for a router to assist in cutting junction box apertures at preselectable positions in wall surfaces which may be vertically or horizontally disposed.

Description:
FIELD OF THE INVENTION 
     This invention relates to a template assembly useful for the placement of apertures for junction boxes and other electrical power and communication devices that accommodate switches, receptacles, telephone outlets, data outlets, and the like. It relates in particular to the provision of a guide for a router used in cutting such apertures. 
     BACKGROUND OF THE INVENTION 
     During a remodeling or new construction project, electricians or drywallers are required to appropriately place in sheetrock or other wall materials apertures where junction boxes and other electrical power and communication devices will be located. When measuring for the cut-out sections in the walls, the installer will typically use a ruler to measure the appropriate location of the cut-out, and then trace a junction box with a pencil to outline the shape to be cut out. The marking and cutting out of junction box locations by this procedure requires a considerable amount of time and labor. Due to the time constraints and high cost of labor involved in construction projects, there is a great need for a device which will expedite the locating of cut-outs on new and existing walls to accommodate boxes for devices. Additionally, the traced outline is then cut with a saw, a router or other cutting instrument, following the traced line. If the operator of the cutting instrument misdirects the cutter, the cut may not be appropriately sized. 
     SUMMARY OF THE INVENTION 
     While previous inventions have provided templates which facilitate the locating of positions for cutouts, the present invention not only assists in properly locating cutouts, but meets a further need by providing a guide for the tool used in cutting apertures in walls to accommodate junction boxes and other electrical power and communication devices. Further, the present invention provides a template that not only assists in cutting of such apertures in a vertical wall, but also in cutting of such apertures in horizontally disposed walls boards, as are encountered in the manufactured housing industry, modular housing industry and recreational vehicle industry. 
     The device is used to control the cuts made in drywall and other applicable materials by routers. It expedites the process by allowing an adjustable “ladder” type template assembly to be preset at the installer&#39;s predetermined wall box height. The dimensional cut of a hole is controlled with sliding templates that can be set to any desired height and used to guide the router bit by means of a collar fitted so that the router performs the cut in the drywall while tracing the inside edge of either a single gang or a double gang template. The device is designed to work particularly well in fast-paced, repetitious environments such as at construction sites or in the aforementioned housing and recreational vehicle industries. 
     In most commercial and domestic building environments, junction boxes are commonly positioned at either of two standard heights above floor level. Typically, electrical outlets are centered at a height of one foot, while switches are at a four-foot height. The present invention preferably has two templates, one corresponding to each height, but capable of adjustment in half-inch increments to take account of variations in local construction practices or building codes. 
     In summary, it is a purpose of this invention to provide a template assembly which functions as a guide for a router in repetitiously cutting apertures at standard heights in walls to accommodate electrical fixtures. 
     It is further a purpose of this invention to provide a template assembly which functions as a guide for a router in repetitiously cutting apertures at two standard heights in walls to accommodate electrical fixtures, both heights being readily adjustable to meet variations in standards. 
     It is further a purpose of this invention to provide a template assembly which functions as a guide for a router in repetitiously cutting apertures at two heights in walls to accommodate electrical fixtures, the assembly being easily and reversibly dismantled into compact portable sections. 
     It is further a purpose of this invention to provide a template assembly which can readily be configured as a guide for repetitiously cutting apertures at standard heights either in vertical walls or in horizontally positioned wall boards. 
     It is further a purpose of this invention to provide a template assembly which functions as a guide for a router in repetitiously cutting apertures at standard heights in walls to accommodate electrical fixtures, the assembly having templates which are easily and reversibly removable for independent use in non-standard applications. 
     It is finally a purpose of this invention to provide a template assembly which functions as a guide for a router in repetitiously cutting apertures at standard heights in walls to accommodate electrical fixtures, the assembly being readily adaptable by the user to be operable in more confined spaces than normal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a template assembly according to various embodiments of this invention. 
     FIG. 2 is a side view of the assembly of FIG.  1 . 
     FIG. 3 is an end elevation of an adapter. 
     FIG. 4 is a side elevation of an adapter. 
     FIG. 5 has a side elevation of an adapter and members of a rail. 
     FIG. 6 is a cross-sectional view taken along line A—A of FIG.  1 . 
     FIG. 7 is a plan view of a round crossbar. 
     FIGS. 8,  9  and  10  show a slide in plan and end and side elevations. 
     FIGS. 11 and 12 show a template in plan and end elevation. 
     FIG. 13 shows a side elevation of a collar engaged with a router bit. 
     FIGS. 14,  15  and  16  show an end piece in plan and side and end elevations. 
     FIGS. 17 and 18 show partial side elevations of the assembly with cutaways to show in cross-section its disposition relative to a routing tool and, respectively, to a vertical wall and a horizontal board. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2 illustrate a template assembly  20  according to various preferred embodiments. Template assembly  20  has two metal parallel rails  22 , each of which is comprised of a first end member  24 , a generally similar second end member  26 , and a central member  28  extending therebetween. In the illustrated embodiment, first end members  24  and second end members  26  have a square cross-section tubular construction, and central members  28  have a round tubular construction. Each end member  24 ,  26  has a plurality of holes  30  transversely aligned in pairs along the length of the members, some of which are mechanically functional, as will be seen, while others may be present for the purpose of reducing weight of the overall assembly. Central members  28  have a plurality of holes  32 , also transversely aligned in pairs, which are preferably equally spaced along the length of members  28 . Similarly to holes  30  in end members  24  and  26 , several of the holes  32  have mechanical functions, but others may be included to reduce the weight of the overall assembly. In the following description, the various holes in rails  22  used for attachment purposes are comprised among holes  30  or  32 , as appropriate. 
     The central member  28  engages with the end members  24  and  26  as follows. An adapter  34 , shown in more detail in FIGS. 3,  4  and  5  is located at an extremity of each member  24  and  26 . The adapters  34  have generally square cross section and are sized to have an interference-fit when inserted into the extremity of each end member  24  and  26 . Each adapter  34  has a longitudinal cylindrical hole  36  extending through its entire length. With the complete length of adapter  34  inserted inside the extremity of end member  24  or  26 , an end of central member  28  is inserted into the cylindrical hole  32 , the diameter of which is sized to provide a snug fit for central member  28 , while allowing removal if desired. In the illustrated embodiment, four adapters  34  are located at the four locations where central members  28  are connected to end members  24  and  26 . The exploded view of FIG. 5 shows how an adapter  34  is used to engage central member  28  with, for example, second end member  26 . FIG. 6 is a cross-section view taken along line A—A of FIG. 1, and illustrates the aforementioned members secured together by a fastener  38 , such as a screw or bolt, which passes through a hole  30  in end member  26 , a hole  32  in central member  28 , and a hole  40  in adapter  34 , each of these holes being aligned with one another. In the illustrated embodiment, fastener  38  is tightened by engaging with a nut  42 . 
     The rails  22  thus formed are connected by various crossbars and are parallel to one another. The first end members  24  are joined by crossbars  44  at their outer ends and at a point near adapters  34 . In the illustrated embodiment, the crossbars  44  have a square cross section tubular construction, and are attached to the members  24  at one pair of holes  30  with fasteners, for example, threaded rods  46  that extend all the way through the crossbars interiors and through the inner wall of each end member  24  to engage with nuts  48 . The second end members  26  are similarly connected to one another with crossbars  44  and threaded rods  46 . Round crossbars  50 , shown in more detail in FIG. 7, connect the central members  28  to one another with fasteners, for example, with screws  54  that extend through selected pairs of holes  32  in the central members  28  and engage with threaded holes  52  in each end of crossbars  50 . The structure which has been described up to this point, comprising the parallel rails  22  connected by several cross members  44  and  54 , resembles a ladder. 
     FIGS. 8,  9  and  10  illustrate a slide  56  that is slidingly disposed on two opposed end members  24 . In the illustrated embodiment slide  56  has a generally rectangular shape, and may be fabricated from a rectangular section of sheet metal that is shaped to provide the profile seen in FIG.  9 . Specifically, the rectangular section of sheet metal is first bent perpendicularly to its original plane along lines defined by the distance between the outermost sides  58  of first end members  24 , then bent inward along lines defined by the thickness of an individual end member  24 . Alternately, slide  56  may be molded from a plastic or formed from another relatively rigid material. In any even, the slide  56  is preferably comprised of a main area  60 , sides  64  and flanges  65 , which, when slide  56  is in position, the sides  64  and flanges  65  wrap around both the first end members  24  in such a way that slide  56  is generally free to move in either direction along the first end members  24 , unless attached to the end members  24  as described below. Slide  56  has in its main area  60  a rectangular opening  62  which allows access by a router bit to a surface into which it is desired to cut an aperture. 
     Slide  56  has drilled along its sides  64  a plurality of transversely disposed holes  66  spaced relatively closely together, for example, holes with centers spaced in 0.5-inch (12.7 mm) increments. Holes  66  are adapted to receive a fastener to prevent slide  56  from sliding along end members  24 . In other words, holes  66  are aligned with holes  30  in the end members  24 , and fasteners are inserted in the aligned holes to lock the slide  56  at a predetermined position along end members  24 . In the illustrated embodiment, such fasteners comprise screws  68  which engage with press-in locknuts  70  that are disposed in four positions along outermost sides  58  of first end members  24 , the locknuts  70  being recessed in sides  58  so as not to interfere with the positioning of slide  56 . The separation between adjacent locknuts  70  is an exact multiple of the incremental separation of holes  66  in slide  56 . In other words, the combined effect of having several positions for locknuts  70 , and multiple holes  66  in slide  56 , is to provide a wide range of positions at which the slide  56  can be attached to first end members  24 , in small increments defined by the incremental spacing between holes  66 . 
     A template  72 , shown in more detail in FIGS. 11 and 12, may be fabricated from a metal plate or other relatively rigid material, and preferably has a generally rectangular shape. Near each corner of template  72  are holes  74  which are sized to provide clearance for fasteners, such as screws  76 , by which template  74  is affixed to slide  56 . In the illustrated embodiment, screws  76  engage with corresponding threaded holes  78  near the corners of slide  56 . Template  72  has a generally rectangular opening  80  which is larger than the opening  60  in slide  56 , thus leaving a portion of main area  60  of slide  56  exposed to form a shelf  82 . Besides being used as part of template assembly  20 , template  72  may be used independently for a non-routine application which demands the corresponding aperture size of opening  80 ; for example, template  72  may be removed from slide  56  and fastened through holes  74  directly into a work surface, such as a piece of plywood, to enable the cutting of an aperture therein. 
     The opening  80  in template  72  is sized to engage with a circular spacing collar  84  which is concentrically attached to a router bit  86 , as in various conventional routers. The collar  84  and bit  86  are shown in FIG. 13, and FIGS. 17 and 18 illustrate two configurations of a collar with a bit positioned in template  72 . Collar  84  has a cylindrical stem  88  integral with a cylindrical end portion  90  that includes a side  92  and a bottom surface  94 . Bit  86  projects far enough below surface  94  of collar  84  to pass entirely through the article being cut out, allowing for the relevant thickness of slide  56 . When the tool is in operation, the bit  86  rotates in conjunction with collar  84 . In the following, it is assumed that the template assembly  20  is in position against a wall or board or other surface into which an aperture is to be cut. The bottom surface  94  of collar  84  is positioned squarely on the shelf surface  82  in order to provide stability for the routing tool. With the router motor engaged, the operator moves the router so that the side  92  of the collar  84  is in contact with the shoulder formed by opening  80  of template  72 , using this shoulder to trace the path defined by the template opening  80  until the entire area perimeter of the opening has been followed, at which point a section of wall or board material will have been completely severed from its surrounding area, causing an aperture to be formed. The end portion  90  of collar  84  has a predetermined, standard diameter, and the template opening is sized accordingly to accommodate the diameter of collar  84  and provide the desired, correctly sized aperture removed from the work surface by the cutting operation. 
     The foregoing description has concentrated on slide  56  and template  72 , which are associated with the first end members  24 . Referring to FIG. 1, a second slide  96  and a second template  98 , located along end members  26 , have a similar construction as first slide  56  and first template  72 , respectively. However, in the embodiment illustrated in FIG. 1, the openings of slide  56  and of template  72  are sized, in conjunction with the diameter of collar  84 , to yield a double gang aperture from the cutting operation, that is, for a situation in which two switches or outlets are to be mounted side-by-side, whereas the second slide  96  and the second template  98  have smaller openings designed for a single gang aperture. 
     FIGS. 14,  15  and  16  illustrate in detail the end piece  100  extending between the ends of end members  26 . End piece  100  serves as a guide for the assembly. As viewed in FIG. 16, end piece  100  is generally U-shaped, comprised of a central flat portion  101  and brackets  102 . The end piece  100  is adapted for connection to both the second end members  26 , for example, with fasteners such as bolts  106  and nuts  108  received in holes  104  aligned with holes  30  in end members  22 . 
     In FIGS. 14 and 15, a flat portion  110  can be seen, which is also shown in FIG. 2 projecting perpendicularly from the rails  22 . The end piece  100  is designed to be attached to second end members  26  so that both an outer surface  112  and an inner surface  114  are squarely aligned with respect to the longitudinal direction of the template assembly  20 . 
     End piece  100  allows template assembly  20  to function in either of two modes. In one mode, it can be used at a building or remodeling location, where a wall is already in position. In this case, assembly  20  is vertically disposed in a chosen location against the wall, with the outer surface  112  of end piece  100  placed flat against a floor to aid in achieving a correct vertical alignment. In another mode, it can be used in prefabrication environments, such as are encountered in the manufactured housing, modular housing and recreational vehicle industries. In these industries, wall materials are frequently handled in a horizontal plane while resting on a support table. In such a case a wall board is lined up with an edge of the table, and the template assembly  20  is positioned appropriately, using the inner surface  114  of end piece  100  against the table edge to aid in aligning the template assembly  20  with the workpiece supported on the table support surface. 
     It should be emphasized that the orientation of the end piece  100  with respect to rails  22 , and slides  56  and/or  96  thereon, differs between the aforementioned modes of use. FIGS. 17 and 18 show side elevations of template assembly  20  partially cut away to show in cross-section the orientation of the end piece with respect to a slide  56  including template  72 . 
     In FIG. 17, the template assembly  20  is oriented vertically against an existing wall  116 ; the end piece  100  has its surface  112  of the flat portion  110  placed flush against the floor  118  and projecting away from the wall to allow the slide  56  to be disposed flush against the wall. However, when the assembly  20  is used as in FIG. 18, with a board  120  disposed on a horizontal table  122 , end piece  100  is reoriented to project downwards so that surface  114  can engage with the edge of table  122  and workpiece  120 . It is evident, therefore, from FIGS. 17 and 18 that the flat portion  110  of end piece  100  projects in opposite directions for the two modes of use. This is simply achieved by disengaging the fasteners, for example screws  34  and nuts  42 , from second end members  26 , then removing end piece  100 , reversing its orientation, and finally reattaching it to second end members  26 . Since the template assembly  20  is intended for repetitious operations, it would be comparatively rare for a given user to change the mode of use, and reversal of end piece  100  would not be an inconvenience; in all probability it would be a once-only operation. On the other hand, from the point of view of the fabricator, the versatility of the making same item for both modes of application represents a saving in manufacturing cost which can be passed on to the customer. 
     Accordingly, end piece  100  defines the bottom of the template assembly  20 . It is normally more frequent to have double gang situations in higher positions above floor level, as for example with light switches, and to have single ganging at lower levels, as represented by power outlets. It would therefore be most common for the different sized templates of this invention to be placed with the smaller template nearer to the bottom of assembly  20 , and the larger template nearer to the top. Although this would be the most preferred disposition of templates, it would equally be possible to have two smaller or two larger templates on a given assembly. Furthermore, certain electrical switches and outlets are designed to be self-contained, that is, directly attached to electrical conductors instead of requiring a junction box. These require smaller apertures than junction boxes, and the template openings can be sized accordingly. 
     The preferred material for the rails  22 , adapters  30 , crossbars  44  and  50 , slides  56  and  96 , and templates  72  and  98  is aluminum. According to one embodiment of this invention: the end members  24  and  26  and their corresponding crossbars  44  preferably have a 1-inch (25 mm) square cross section and a 0.0625-inch (1.6 mm) wall; end members  24  and  26  are 22 inches (0.56 m) long, and crossbars  44  are 7 inches (0.18 m) long; the central members  28  have a 0.75-inch (19 mm) diameter, a 0.125-inch (3.2 mm) wall and a 20-inch (0.51 m) length, and their corresponding crossbars  50  are constructed of 0.5 inch (12.7 mm) rod with a length of 7.44 inches (0.19 m). When assembled with a 2-inch (50 mm) overlap between central and end members, the overall length of the device is 60 inches (1.52 m). For this embodiment, the slides  56  and  96  are fabricated from 0.125-inch (3.2 mm) thick stock and the templates  72  and  98  from 0.375-inch thick (9.5 mm) stock. 
     The sectional nature of template assembly  20  offers the user advantages which would not be provided by a comparable device with integral rails. For instance, it may be necessary in some situations to repetitively cut apertures in walls with insufficient space to place the template assembly  20  as supplied. In such cases, the device can be shortened by removing the central members  28  from either the first end members  24  or the second end members  26 , cutting down the central members  28  to an appropriate length, and resecuring them to the end members through different holes  32  than previously. Also, the round crossbars  50  may be removed and reattached at other points to provide optimum strength and symmetry. 
     Furthermore, the user may completely disengage the central members  28  from end members  24  and  26  by removing the fasteners. The device is now dismantled into three short sections based on the central members  28  and each of the end members  24  and  26 . Since no section exceeds 22 inches (0.56 m) in length, it is more readily portable than the complete assembly and may, for instance, easily be stowed in an aircraft luggage compartment and reassembled later. 
     Sometimes, it is necessary to make apertures for ganging together more than two electrical fixtures. In such a case, the invention can be used to cut out a first aperture, then it can be moved just far enough along to cut out an adjacent second area which extends the size of the first aperture. 
     While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation of material to the teachings of the invention without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.