Abstract:
A tool for cutting drywall bead that has a shaped cross section and requires cutting to length with both straight and angled cuts. The tool includes a base with a first handle attached thereto and a second handle pivotably attached to the base, and a blade with a cutting edge movably engages the base. An anvil pivotably attaches to the base and may be rotated to a chosen angle relative to the blade, and the anvil has a shaped upper surface which complimentarily engages the shaped cross section of the drywall bead. A mechanical linkage forces the cutting edge of the blade towards the anvil when the second handle is biased towards the first handle such that a drywall bead positioned over the anvil is cut at a desired angle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/388,516, filed on Jun. 13, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention generally relates to hand tools. More particularly, the present invention relates to a drywall bead press used to make precise and consistent straight and angular cuts to drywall bead.  
           [0004]    2. Description of the Related Art  
           [0005]    Modern framing and drywall often includes corner bead material. The product is widely used to create round and otherwise finished corners. A number of obstacles face a construction worker in the installation of drywall corner bead. Traditional hand snips utilized in the construction industry are imprecise. For example, an angled cut must be made to match two opposing pieces of drywall bead material in a doorframe corner. The precision of the cut is important to ensure that drywall tape and mud can be applied to a smooth base, thereby ensuring a smooth and continuous surface in the finished wall. Often, large pieces of drywall bead material must be discarded following a less than perfect cut using hand snips.  
           [0006]    Another problem is the contoured cross-sectional shape of the drywall bead. If traditional had snips are used to cut the material, the straight cutting action of the snips crushes and distorts the contoured cross-section at the cut location. At a corner where both opposing pieces of drywall bead must be cut, the damaged cross-sectional shape of the adjoining pieces may easily result in a blemish in the finished surface. To compound the problem, modern architectural design often calls for walls and other interior surfaces that intersect at odd angles. In this situation, construction workers often apply a cut and fit approach which is both inefficient and often produces less than satisfactory results.  
           [0007]    Accordingly it would be advantageous to provide a tool that eliminates the imprecision of hand-eye gauged drywall bead cutting that increases the precision of drywall bead cuts by controlling the angle of the cut, that does not distort the drywall bead cross-section and that helps to eliminate the disposal of costly construction materials. It is thus to such a drywall bead press and method that the present invention is primarily directed.  
         SUMMARY OF THE INVENTION  
         [0008]    The disadvantages of the prior art are overcome by the present invention which, in one aspect, is a tool for the precise cutting of drywall bead, the drywall bead having a shaped cross section and requiring cutting to length. The tool comprising a base with a first handle attached to the base. A second handle engages the base such that the handle is movable relative to the base. A blade having a cutting edge engages the base and is movable relative the base. An anvil pivotally attaches to the base. The anvil is rotatable to an angle relative to the blade and has a shaped upper surface suitable for complimentarily engaging the shaped cross section of a length of drywall bead. A section of drywall bead to be cut is positioned over the anvil. A mechanical linkage forces the cutting edge of the blade towards the anvil when the second handle is biased towards the first handle such that the drywall bead is cut at an angle. The blade of the tool being readily replaceable when in dulls.  
           [0009]    In another aspect, the blade slideably engages the base such that biasing the second handle toward the first handle forces the cutting edge of the blade to move linearly towards the anvil. The mechanical linkage used in the tool is a rack and pawl assembly.  
           [0010]    In yet another aspect, the blade pivotably engages the base such that biasing the second handle towards the first handle forces the cutting edge of the blade to rotate toward the anvil. The mechanical linkage used is a scissor linkage.  
           [0011]    In yet another aspect, the shaped surface of the anvil has a recessed channel into which the cutting edge of the blade is received when the second handle is biased towards the first handle. The drywall bead is cut at a 45 degree angle across the shaped cross section.  
           [0012]    In yet another aspect, the invention provides a tool for the precise cutting of drywall bead, the drywall bead having a shaped cross section and requiring cutting to length. The tool comprising a base with a first handle attached to the base. A second handle engages the base such that the handle is movable relative to the base. A blade having a cutting edge engages the base and is movable relative the base. An anvil pivotally attaches to the base. The anvil is rotatable to an angle relative to the blade and has a shaped upper surface suitable for complimentarily engaging the shaped cross section of a length of drywall bead. A section of drywall bead to be cut is positioned over the anvil. The invention includes a means for forcing the cutting edge of the blade towards the anvil when the second handle is biased towards the first handle such that the drywall bead is cut at an angle.  
           [0013]    The invention further provides a method for cutting drywall bead at an angle. The drywall bead has a shaped cross section and requires cutting to length. The method includes the steps of placing the anvil of a cutting device onto a section of drywall bead. The anvil has a shaped surface thereon suitable for complimentarily engaging the shaped cross section of the drywall bead. The anvil is pivotally attached to a base of the device such that the anvil may be rotated to a chosen angle relative to the base. The base further having a first handle rigidly attached thereto and a second handle engaged therewith such that the second handle may move relative to the base. The device further having a blade movably engaged with the base and including a cutting edge. A mechanical linkage is between the second handle and the blade such that operation of the second handle forces the cutting edge of the blade towards the anvil. The section of drywall bead is then cut at an angle by biasing the second handle towards the first handle. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a side-perspective view of the drywall bead press.  
         [0015]    [0015]FIG. 2 is a side-elevation view of the tool of FIG. 1.  
         [0016]    [0016]FIG. 3 is an exploded view of the apparatus of FIG. 1, illustrating the tool assembly including the rack and pawl mechanism, stop pawl and springs.  
         [0017]    [0017]FIG. 4 is a side-cross sectional view of the tool of FIG. 1, illustrating the internal components of the tool in operation.  
         [0018]    [0018]FIG. 5 is a side-perspective view of an alternative embodiment of the drywall bead press. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    With reference to the figures in which like numerals represent like elements throughout, FIG. 1 is a side perspective view of one embodiment of the drywall bead press  10 . As shown in FIG. 1, the drywall bead press  10  includes a fixed handle  14  connected to a base  12 . A pivoting handle  16  is also connected to base  12  by screw  18 . An anvil  20  is connected to the base  12  by screw  22  and may rotate relative to the base  12 . The drywall bead to be cut is positioned upon the shaped upper surface  24  of the anvil  20 . FIG. 2 is a side elevation of the drywall bead press. As shown in FIG. 2, the drywall bead press  10  includes a blade  26  with a sharpened edge  28 . A reference plane of the anvil  20  is defined as including the centerline of screw  22  and passing through the centroid of the anvil  20 . The angle formed between the plane of the blade  26  and the reference plane of the anvil  20  determines the angle at which the drywall bead will be cut.  
         [0020]    [0020]FIG. 3 is an exploded view of the drywall bead press  10 . As shown in FIG. 3, the fixed handle  14  and base  12  may be combined into a single component. In an alternative embodiment, the fixed handle  14  may be a separate component and attached to the base  12 . The base  12  includes a guide channel  30  into which the blade  26  is inserted. The blade  26  has a toothed edge  32  and a slot  34  running parallel to the toothed edge  32 . During assembly, the blade  26  is inserted into guide channel  30  and retained in the base  12  by stabilizer screws  40 . The stabilizer screws  40  pass through the base  12  and engage the blade  26  by passing through slot  34 . The stabilizer screws  40  are secured in position by nuts  42 . The blade  26  is readily replaceable if it becomes dulled with use, by removing stabilizer screws  40 , removing the old blade  26  and inserting a new blade  26 , and reinstalling stabilizer screws  40 .  
         [0021]    As further shown in FIG. 3, the anvil  20  has a shaped upper surface  24 . A portion of drywall bead  46  is shown above the shaped upper surface  24  of the anvil  20 . The shaped upper surface  24  matches the contour of the drywall bead  46 . The sharpened edge  28  of the blade  26  also substantially matches the contours of the drywall bead. In operation, the shaped upper surface  24  supports the drywall bead  46  as it is cut by blade  26 . The shaped upper surface  24  thus prevents crushing or distortion of the drywall bead  46  as it is cut. The anvil  20  also includes shallow recessed channels  48  in the shaped upper surface  24 . The recessed channels  48  are positioned in the shaped upper surface  24  in alignment with blade  26  when the anvil  20  is rotated to a 45 degree angle between the plane of the blade  26  and the reference plane of the anvil  20 . In operation, as the blade  26  cuts the drywall bead  46  the sharpened edge  28  of the blade  26  passes into the recessed channels  48 . By passing into the recessed channels  48  the sharpened edge  28  of the blade  26  is not dulled by contacting the anvil  20 .  
         [0022]    In an alternative embodiment, the anvil  20  does not have recessed channels  48  and the sharpened edge  28  of the blade  26  cuts the drywall bead  46  by pressing against the shaped surface  24  of the anvil  20 . In another embodiment, the recessed channels  48  may only extend along a portion of the shaped surface  24 . In this embodiment the sharpened edge  28  of the blade  26  will pass into the recessed channels  48  along a portion of shaped surface  24 . In the remaining portion of shaped surface  24 , the sharpened edge  28  of the blade  26  cuts the drywall bead  46  by pressing against the shaped surface  24  of the anvil  20 . In another embodiment, the blade  26  does not completely cut through the drywall bead  46 , but scores the material so that the drywall bead  46  may be broken by hand at the desired location. In another embodiment, the drywall bead is cut at angles other than 45 degrees and additional recessed channels  48  are included in the shaped surface  24  at angles other than 45 degrees relative to the plane of blade  26 , such as 15 degrees, 30 degrees and other angles therebetween. A recessed channel  48  is also included at 0 degrees or perpendicular to the drywall bead  46  for making straight cuts.  
         [0023]    As further shown in FIG. 3, pawl  50  is inserted into pivoting handle  16  and secured by pawl screw  52 . The pawl screw  52  passes through hole  54  in pivoting handle  16  and through pawl  50  and is secured with nut  56 . Stop pawl  60  is inserted into the base  12  and secured by stop pawl screw  62 . The stop pawl screw  62  passes through hole  64  in the base  12  and through stop pawl  60  and is secured with nut  66 . Both pawl  50  and stop pawl  60  are free to rotate about screws  52  and  62  respectively.  
         [0024]    [0024]FIG. 4 is a side cross sectional view of the drywall bead press  10 . As shown in FIG. 4, the anvil  20  is restrained in a chosen angular orientation by anvil lock bead  70 . The anvil  20  may be rotated about screw  22  to an angle relative to the blade  26 . As the anvil  20  is rotated from one angular position to another the lock bead  70  slides along the bottom of the anvil  20  until it rests in a lock bead recess  72 . The lock bead  70  and lock bead recess  72  ensure alignment of the blade  26  with the recessed channel  48  when making a cut. In an alternative embodiment, the drywall bead is cut at angles other than 45 degrees and multiple lock bead recesses  72  are included in the anvil  20  at positions other than 45 degrees relative to the blade  26 , such as 0 degrees, 15 degrees, 30 degrees and other angles therebetween.  
         [0025]    As further shown in FIG. 4, pawl  50  is held in contact with the toothed edge  32  of the blade  26  by pawl torsion spring  58 . The stop pawl  60  is also held in contact with the toothed edge  32  of the blade  26  by stop pawl torsion spring  68 . The pivoting handle  16  is urged to an open position by handle torsion spring  78 . The blade  26  is urged to a retracted position away from anvil  20  and into the base  12  by compression spring  80 .  
         [0026]    In operation, as the pivoting handle  16  is biased towards the fixed handle  14  in the direction of Vector A, pawl  50  is forced into toothed edge  32  of the blade  26 . As pressure is further applied to pivoting handle  16 , the blade  26  is forced out of the base  12  and towards the anvil  20  in the direction of Vector B. The movement of the blade  26  is restrained by guide channel  30 , as best shown in FIG. 3, and stabilizer screws  40  running in slot  34 . The blade  26  moves linearly out of the base  12  and towards the anvil  20 . When the pressure is released on the pivoting handle  16 , stop pawl  60  engages the toothed edge  32  of the blade  26  and prevents retraction of the blade  26  into the base  12 . As the pivoting handle  16  is biased away from the fixed handle  14  by handle torsion spring  78 , the pawl  50  ratchets down the toothed edge  32  until the pivoting handle is fully released. Since the blade  26  has been forced out of the base  12 , the pawl  50  will engage a new tooth farther up the toothed edge  32  than the tooth engaged in the previous position. The toothed edge  32  functions as a rack for the engagement of the pawl  50  and together the components form a rack and pawl assembly as is commonly known in the art.  
         [0027]    During a drywall bead cut, the pivoting handle  16  is repeatedly biased towards the fixed handle  14 , the blade  26  is forced out of the base  12  and toward the anvil  20  with great force. A length of drywall bead positioned upon the anvil  20  is then cut by the advancing blade  26 . After the cut is completed, the blade  26  may be retracted by applying pressure to the rear portion  84  of the stop pawl  60 . Pressure applied to the rear portion  84  of the stop pawl  60  will cause the stop pawl  60  to pivot away from toothed edge  32 . As the stop pawl  60  pivots the stop pawl  60  also contacts the pawl  50  and forces the pawl  50  to disengage from the toothed edge  32  of the blade  26 . The blade  26  is then urged to a retracted positioned by compression spring  80  acting upon the fixed handle  14  and the upper portion of blade  26 .  
         [0028]    [0028]FIG. 5 shows an alternative embodiment of the drywall bead press  10  that may be used to practice the present invention. As shown in FIG. 5, a blade  90  is directly attached to a pivoting handle  92  and the anvil  94  is pivotably attached to a fixed handle  96  by a pivot screw  98 . In this configuration, the effective fulcrum length of the fixed handle  96  and pivoting handle  92  is substantially longer than the effective fulcrum length of the blade  90  and anvil  94  about handle pivot screw  100 . The mechanical advantage provided by the longer fulcrum of the pivoting handle  92  and fixed handle  96  produces sufficient force to cut a length of drywall bead positioned upon the shaped upper surface  102  of the anvil  94 . In this configuration, the fixed handle  96 , pivoting handle  92 , blade  90  and anvil  94  form a scissor linkage as is commonly known in the art. As will be appreciated by one skilled in the art, other mechanical linkage configurations are possible which provide sufficient force to cut the drywall bead.  
         [0029]    While there has been shown a preferred embodiment of the present invention, those skilled in the art will appreciate that certain changes may be made in the forms and arrangement of the elements for a drywall bead press without departing from the underlying spirit and scope of the invention defined by the following claims.