Abstract:
A tool for use in cutting drywall is provided. The tool is comprised of a plate with at least one indentation it the top edge of the plate. The tool is placed flush against a piece of drywall so that the drywall may be cut with indentations matching the at least one indentation in the top edge of the plate. In a further embodiment of the invention, a plurality of the plates are joined together. A method for cutting at least one indentation in a plate comprising placing the plate against drywall and cutting the drywall to match the at least one indentation.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a tool for cutting drywall.  
       BACKGROUND OF THE INVENTION  
       [0002]     Drywall is an essential component in conventional building construction. The skeleton of an interior room in a building includes vertical corner posts which bookend upright supports, known as studs. The studs constitute the structural support for the non-load bearing walls in a building. Sheets of drywall are attached to the opposing sides of studs and extend from floor to ceiling.  
         [0003]     Vertical corner posts are normally metallic and recently metal studs have gained acceptance amongst builders. As a result, these components of a building&#39;s construction are fire-resistant. The drywall is also fire-resistant, which helps to contain a fire within a single room. To ensure that the fire is contained, the boundaries between the ceilings and the walls must be well sealed.  
         [0004]     Sealing the boundary between a wall and the ceiling of a room is particularly challenging when the ceiling is fluted decking. Normally, concrete is poured onto fluted decking to form the floor above. The decking itself is steel with downwardly facing, concave channels and may be left exposed for cosmetic reasons. The channels are also known as flutes.  
         [0005]     The decking extends along the length of a building such that the walls of individual rooms meet the decking transversely. Where the walls extend along the length of a channel, there will be little potential for gaps at the meeting points. However, where the plane of the wall is transverse from the planes of the channels, there will be gaps where the walls meet the decking unless the drywall is cut or shaped to fit within the channels.  
         [0006]     Recently there has been a trend toward attempting to prevent the spread of fire beyond interior walls by adding strict provisions to fire code regulations. Fire-resistant insulation is packed in the flute openings between rooms to prevent the spread of flames. If the gap between the drywall and the roof flutes is not properly sealed, expensive fire retardant spray must be applied to the insulation. Even after fire-retardant spray is applied, there are significant risks. When a fire is burning in a room, the smoke generated by the fire creates pressure. This pressure has been known to force the insulation from its placement between the walls, thus opening a passage for the spread of flames.  
         [0007]     Therefore, to secure the insulation within the cavity between the walls, fire code regulations now require the precise cutting of drywall so that its top edge fits within the deck flutes. Hand cutting the top edge of the drywall can be labour intensive and may add significantly to the costs of construction. Furthermore, hand cutting frequently results in the drywall fitting poorly at the border of the deck flutes and the interior walls. Extensive caulking or the addition of fire tape at the gap between the drywall and the ceiling will then be necessary.  
       SUMMARY OF THE INVENTION  
       [0008]     In view of the deficiencies of the prior art, a tool is provided for use in cutting varied lengths of drywall sheets to match the profile of a surface against which the drywall is to be mounted.  
         [0009]     Accordingly, in one aspect of the invention, an apparatus is comprised of a plate with a bottom edge, a top edge, a first side edge and a second side edge. The plate has at least one indentation on its top edge between the first side edge and the second side edge. The apparatus can be placed flush against drywall such that the drywall may be cut with indentations matching the at least one indentation in the top edge of the plate.  
         [0010]     In a further aspect of the invention, the apparatus is comprised of a plurality of plates joined together. Each of the plates has a bottom edge, a top edge, a first side edge and a second side edge. Each of the plates also has at least one indentation on its top edge between the first side edge and the second side edge. The apparatus can be placed flush against drywall such that the drywall may be cut with indentations matching the at least one indentation in the top edge of each of the plates.  
         [0011]     A further aspect of the invention is a method for cutting drywall using a plate with at least one indentation in a top edge of the plate and comprising the steps of placing the plate against the drywall and cutting the drywall to match the at least one indentation. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The invention is best understood from the following detailed description when read in connection with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawings are the following Figures:  
         [0013]      FIG. 1  is a perspective view of a first exemplary embodiment of the invention with one plate;  
         [0014]      FIG. 2  is a perspective view of a second exemplary embodiment of the invention with two plates in an open position;  
         [0015]      FIG. 3  is a perspective view of the second embodiment of the invention with two plates in a closed position;  
         [0016]      FIG. 4   a  is a cross-sectional view of the second embodiment of the invention, taken along line  4   a - 4   a  of  FIG. 2 , with a fastener in a tightened position;  
         [0017]      FIG. 4   b  is a cross-sectional view of the second embodiment of the invention, taken along line  4   a - 4   a  of  FIG. 2 , with the fastener in a loosened position;  
         [0018]      FIG. 5  is a perspective view of the second embodiment of the invention with two plates apart from one another;  
         [0019]      FIG. 6  is a perspective view of a third exemplary embodiment of the invention;  
         [0020]      FIG. 7  is a top view of the third embodiment of the invention with a fastener in a tightened position; and  
         [0021]      FIG. 8  is a perspective view of the second embodiment of the invention in situ relative to a partially cut sheet of drywall below a roof with deck flutes. 
     
    
     DETAILED DESCRIPTION  
       [0022]     A drywall tool  10  for cutting drywall is shown in  FIG. 1 . The drywall tool  10  is generally comprised of a plate  12 . The plate  12  is desirably substantially flat. Furthermore, the plate  12  may be comprised of any solid material. In one exemplary embodiment of the apparatus, the plate is metallic. A light yet durable metal such as aluminum is desirable. The plate  12  may be constructed in a variety of dimensions to suit the application. One configuration found suitable for cutting drywall for abutting ceiling deck flutes is for the plate  12  to be one quarter inch thick, three inches high and fifty inches long.  
         [0023]     The plate  12  has a bottom edge  14 , a top edge  16 , a first side edge  18  and a second side edge  20 . The bottom edge  14  is parallel to the top edge  16  of the plate  12 . The first side edge  18  and the second side edge  20  are parallel to one another and perpendicular to bottom edge  14  and top edge  16  of the plate  12 . The plate  12  has indentations  22  in the top edge  14 . In one exemplary embodiment of the drywall tool  10 , each of the indentations  22  has opposing sloped edges  24 . The sloped edges  24  meet at an indentation floor  26 . Each indentation floor  26  is parallel to the bottom edge  14  and the top edge  16  of the plate  12 . Furthermore, each indentation floor  26  is equidistant from the bottom edge  14  of the plate  12 .  
         [0024]     In the configuration of the drywall tool  10  shown and discussed herein, the indentations  22  are spaced three inches apart and the indentation floor  26  is one and one half inches long. However, as the skilled person in the art will appreciate, the spacing of the indentations  22  and the length of the indentation floor  26  may vary. The plate  12  may be manufactured such that the indentations  22  may match any profile against which the drywall tool  10  is placed. Furthermore, the plate  12  may be manufactured such that the drywall tool  10  fits snugly against roof flutes of any dimension.  
         [0025]     In a further embodiment of the invention, shown in an open position in  FIG. 2 , the plate  12  is joined to a second plate  28 . The second plate  28  has dimensions identical to the dimensions of the plate  12  and has a first side edge  34 , a bottom edge  36  and a top edge  38 .  
         [0026]     In this embodiment of the invention, the plate  12  has a first aperture  30  and the second plate  28  has a second aperture  32  (as best seen in  FIG. 5 ). Desirably, the first aperture  30  extends through the entire thickness of plate  12  and the second aperture  32  extends through the entire thickness of the second plate  28 . However, one of the first aperture  30  and the second aperture  32  may not extend through the entire thickness of the corresponding plate. In this circumstance, the aperture that does not extend through the entire plate is threaded to accept a threaded fastener.  
         [0027]     It will be appreciated by those skilled in the art that more than two of plates  12 ,  28  can be joined together to form a length of tool  10  suitable for cutting drywall. The embodiment of the two plates  12 ,  28  will be illustrated and discussed for convenience.  
         [0028]     As illustrated, the first aperture  30  is proximate to the second side edge  20  of the plate  12  and the second aperture  32  is proximate to the first side edge  34  of the second plate  28 . Furthermore, the distance between the first aperture  30  and the second side edge  20  and the distance between the second aperture  32  and the first side edge  34  are such that when the first aperture  30  is lined up with the second aperture  32 , the edges  20 ,  34  overlap such that the resulting distance between an indentation  40  closest to the second side edge  20  and an indentation  42  closest to the first side edge  34  is equal to the distance “d” between indentations  22  in each of the plates  12 ,  28 .  
         [0029]     As shown in  FIG. 4   a,  when the first aperture  30  is lined up with second aperture  32 , a fastener  44  may be placed through the first aperture  30  and the second aperture  32  to releasably join the plate  12  and the second plate  28 . The fastener  44  may be a peg, a bolt, a screw or any other elongated device sized to extend through the first aperture  30  and the second aperture  32 . The fastener  44  is threaded and releasably secured in place by a nut  46 . Desirably, the nut  46  has head  48  that may be easily gripped by the user of the drywall tool  10 . Conventional nuts, including wingnuts, may also be used.  
         [0030]     Alternatively, if one of the first aperture  30  or the second aperture  32  does not extend through the plate  12  or the second plate  28 , respectively, that aperture is threaded. The fastener  44  is sized to extend through the non-threaded aperture and engage the threaded aperture in order to releasably secure the fastener.  
         [0031]     A recess  50  in the plate  12  surrounds the first aperture  30 , as shown in  FIG. 5 . In one exemplary embodiment, the recess  50  has a bottom  52 , a top  54 , a first side  56  and a second side  58 . The bottom  52  is parallel to the top  54  and the bottom  52  and the top  54  are perpendicular to the first side  56  and the second side  58  such that the recess  50  is square shaped or rectangular. Furthermore, the bottom  52  and the top  54  of the recess  50  are both parallel to the bottom edge  14  and the top edge  16  of the plate  12 . The depth x of recess  50  is equal to half of the thickness y of the plate  12 .  
         [0032]     A flange  60  surrounds the second aperture  32 . In one exemplary embodiment, the flange  60  has a bottom  62 , a top  64 , a first side  66  and a second side  68 . The bottom  62  is parallel to the top  64  and the bottom  62  and the top  64  are perpendicular to the first side  66  and the second side  68  such that the flange  60  is square shaped or rectangular. Furthermore, the bottom  62  and the top  64  of the flange  60  are both parallel to the bottom edge  36  and the top edge  38  of the second plate  28 . The thickness z of the flange  60  is equal to half of the thickness y of the second plate  28 .  
         [0033]     The recess  50  and the flange  60  are oriented and sized such that when the first aperture  30  is lined up with the second aperture  32  the recess  50  receives the flange  60 . Furthermore, the height and width of the flange  60  are each only slightly less than the height and width of the recess  50 , respectively, such that the flange  60  fits tightly within the recess  50 .  
         [0034]     In a further embodiment (not shown) the recess  50  and the flange  60  are both circular.  
         [0035]     In a further alternative embodiment of the invention shown in  FIGS. 6 and 7 , the plate  12  has a cutout  78  and the second plate  28  has a second cutout  80 . The depth m of the cutout  78  is equal to half the thickness n of the plate  12 . The depth o of the second cutout  80  is equal to half of the thickness n of the second plate  28 . The cutout  78  surrounds the first aperture  30  and extends between the bottom edge  14  and the top edge  16  of the plate  12 . Similarly, second cutout  80  surrounds the second aperture  32  and extends between the bottom edge  36  and the top edge  38  of the second plate  28 . The cutout  78  and the second cutout  80  are mirror images of one another.  
         [0036]     The drywall tool  10  comprised of plate  12  and second plate  28  has an open position, shown in  FIG. 2  and a closed position, shown in  FIG. 3 . To manipulate the drywall tool  10  between these two positions, the nut  46  is loosened by rotating the nut  46  about the fastener  44 . The plate  12  is separated from the second plate  28  such that the flange  60  is no longer nested within the recess  50 , as shown in  FIG. 4   b.  The plate  12  or the second plate  28  may then be rotated one hundred and eighty degrees about the fastener  44  to the open position or the closed position, the plates may be pressed together such that the flange  60  nests within the recess  50  as shown in  FIG. 4   a  and the nut  46  may be tightened.  
         [0037]     Alternatively, if the recess  50  and the flange  60  are circular, the user does not have to separate the plate  12  from the second plate  28  before rotating the plate  12  or the second plate  28  about the other.  
         [0038]     When using the drywall tool  10  for cutting, the drywall tool  10  is placed against a piece of drywall  70 . The length of the drywall  70  to be cut will determine whether the tool  10  will comprise a single plate  12 , a plate  12  and a second plate  28 , or three or more properly oriented plates. The drywall tool  10  may be releasably attached to a piece of drywall by at least one securing means  72 , as shown in  FIG. 8 . The securing means  72  may be a clamp or a clip or anything suitable to hold the tool  10  flush against the drywall  70 . When the flange  60  is tightly nested in the recess  50  and the drywall tool  10  is in the open position, each of the indentation floors  26  of the plate  12  and the second plate  28  will be equidistant from the top edge of the drywall  70 . The drywall  70  is then cut to the shape of the drywall tool  10  such that a resulting profile of a top edge  74  of the drywall  70  fits within fluted roof decking  76 . Alternatively, an outline of the drywalling tool  10  may be traced upon the drywall  70  and the drywall tool  10  may be detached from the drywall  70  before cutting the drywall  70  along the tracings.  
         [0039]     Numerous modifications may be made to the embodiments as described above without departing from the scope of the invention, which is described by the claims.