Abstract:
An apparatus for guiding a hand-held power saw for a precision cut. The guide may be used for obtaining accurate cuts at commonly used angles. Guiding strips and runners define the path of travel of the hand-held power saw to allow for a home-handyperson to easily and efficiently cut a workpiece.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to an apparatus for guiding a hand-held power saw for a precision cut. More particularly, the present invention relates to a portable apparatus for guiding a hand-held power saw to consistently obtain straight and accurate cuts at commonly used angles.  
       BACKGROUND OF THE INVENTION  
       [0002]     There are various products available on the market for assisting an individual with obtaining precision cuts at various angles. However, most of these products are costly, difficult to use, and not very portable, and, therefore, impractical or unsuitable for the around-the-home handyperson.  
         [0003]     Home handypersons are likely to own hand-held power saws. However, it can be difficult to align a workpiece and the hand-held power saw to obtain a cut at the correct angle. It is also difficult to maintain a straight cut by hand. A fine adjustment to a cut (e.g. shaving off 1/8 inches) is also very difficult to obtain by hand. As a result, it is desirable to have an inexpensive product that serves to align and guide a hand-held power saw for obtaining accurate and straight cuts at angles commonly desired by a home handyperson. Parameters for common use by a home handyperson would typically include a workpiece width of up to 5/2 inches and height of up to 1½ inches (the actual dimensions of a 2×6), and angles of ninety, thirty, forty-five and sixty degrees.  
         [0004]     Previously disclosed apparatuses used to guide hand-held power saws have various deficiencies and limitations that negatively impact the accuracy of the cut, the straightness of the cut, in addition to the portability and versatility of the apparatuses, and the ease of using the apparatuses. Many apparatuses require the complicated assembly of many parts, or must be used with yet other products such as clamps. Other apparatuses have parts that are highly susceptible to wear and tear through use and likely to require replacement or repair. Apparatuses requiring much hand-eye coordination for alignment are not user-friendly as they may be confusing, tedious or difficult to manipulate, particularly for those with poorer eyesight, reduced mobility, unsteady hands, or limited dexterity. It is also desirable that a guide not have any parts which may move during the cut and, thus, affect the alignment.  
         [0005]     U.S. Pat. No. 5,226,345 issued to Gamble discloses a portable guide for hand power saws. The invention discloses two guide bars for holding the workpiece in place, one of which guide bars is movable with the use of kerf gauges. Using the kerf gauges, the movable guide bar, and multiple different materials, complicates the design of the guide and increases the expense of its production. The invention has parts which are, as stated in the Gamble patent, subject to wear and tear and will require replacement. The kerf gauges add time to the process for obtaining a cut as the wingnuts on the kerf gauges must be tightened and loosened for each use. The edges used to guide the power saw do not necessarily extend beyond the guide bars and, thus, do not ensure a straight cut through-out as the power saw is not properly supported in alignment at the start and end of the cut. Only two angular alignments are allowed by the invention.  
         [0006]     There exists a market for a product that is portable and convenient for the home handyperson to use for guiding a hand-held power saw to produce straight and accurate cuts at commonly desired angles. Further, it is desirable that the product be easy to assemble, easy to manipulate, inexpensive and not susceptible to significant wear and tear.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention comprises a portable apparatus for guiding a hand-held power saw for obtaining straight and accurate cuts at commonly desired angles. The apparatus comprises a platform having an upper face and a lower face, of which the upper face is operative to receive a downward force, while the lower face is operative to engage a workpiece. Two spaced apart parallel runners extend perpendicularly from the lower face of the platform. A first guiding strip is situated in a plane parallel to the platform when the first guiding strip is in engagement with the runners, forming a first pre-determined angle with the runners. The first guiding strip has a first guiding edge situated on a side of the first guiding edge, which first guiding edge is operative to guide the base of a hand-held power saw in a straight line at said first pre-determined angle. Similarly, the apparatus is also comprised of a second guiding strip which is situated in a plane parallel to the platform when in engagement with the runners. The second guiding strip then transverses the runners at a second pre-determined angle, and a second guiding edge, situated on the side of the second guiding strip, is operative to guide the base of a hand-held power saw in a straight line at the second pre-determined angle. The runners are operative to elevate said platform from a work surface, to guide and engage an elongated edge of the workpiece, and to support and position the base of a hand-held power saw in the plane of the upper surface of the workpiece.  
         [0008]     Other objects and advantages of the invention will become clear from the following detailed description of the preferred embodiment, which is presented by way of illustration only and without limiting the scope of the invention to the details thereof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a top view of the apparatus in accordance with the invention.  
         [0010]      FIG. 2  is a cross section of the apparatus from a side view.  
         [0011]      FIG. 3  is a side view of a guiding strip.  
         [0012]      FIG. 4  is a top view of the apparatus depicting the use of a hand-held power saw to cut a sixty degree angle on a workpiece.  
         [0013]      FIG. 5  is a top view of the apparatus depicting use of the apparatus with the Black &amp; Decker Workmate 400 (Trademark).  
         [0014]      FIG. 6  is a perspective view of an alternative peg.  
         [0015]      FIG. 7  is a perspective view of a peg lock.  
         [0016]      FIG. 8  is a side view of a runner.  
         [0017]      FIG. 9  is a perspective view of a workpiece cut at one end at two angles for a double-angled cut. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     Referring to  FIGS. 1-3 , guiding apparatus  10  has a platform  12  with an upper face  14  and a lower face  16 , and edges  18 ,  20 ,  26 ,  28  and  30 , of which edges  18  and  20  run parallel to each other. Referring to  FIG. 2 , runners  22  and  24  extend perpendicularly to the lower face  16  a distance  25  of 1⅜ inches. The distance  68  between inner edges  70  and  72  of runners  22  and  24  respectively, is 5⅝ inches.  
         [0019]     Runner  22  extends longitudinally beyond edges  26  and  28 , and runner  24  extends longitudinally beyond edges  26  and  30 . Runner  22  has peg holes  31 ,  36  and  40  on its upper surface, and runner  24  has peg holes  34  and  38  on its upper surface. Guiding strip  42  has guiding edge  43 , and pegs  44  and  46 , which extend perpendicularly to lower surface  56  of guiding strip  42  and are operative to engage peg holes  34  and  31 , respectively, to form an angle A of ninety degrees between guiding strip  42  and runners  22  and  24 . Similarly, guiding strip  48  has guiding edge  49 , and pegs  50  and  52 , which extend perpendicularly to lower surface  58  of guiding strip  48  to engage peg holes  38  and  36 , respectively, to form an angle B of forty-five degrees between guiding strip  48  and runners  22  and  24 . So, positioned, guiding strip  48  extends longitudinally in the same direction as edge  28  of platform  12 .  
         [0020]     In an alternate positioning of guiding strip  48 , angle C of sixty degrees is formed between guiding strip  48  and runners  22  and  24  when peg  66  engages peg hole  54  in guiding strip  48  and peg hole  40  in runner  22 , and peg  50  engages peg hole  38 . Edge  30  of platform  12  allows guiding strip  48  to use peg hole  38  for configurations for obtaining each of angles B and C.  
         [0021]     Referring to  FIGS. 1 and 4 , runners  22  and  24  extend longitudinally beyond guiding strip  42 , and also extend longitudinally beyond guiding strip  48  when guiding strip  48  engages runners  22  and  24  to form each of a forty-five degree angle B and a sixty degree angle C. Ends  102  and  104  of runners  22  and  24 , respectively, are tapered at a forty-five degree angle in a line parallel to guiding strip  48  when guiding strip  48  is engaged with runners  22  and  24  at forty-five degree angle. Guiding strips  42  and  48  extend longitudinally beyond runners  22  and  24  when in engagement with runners  22  and  24 .  
         [0022]     Platform  12  has peg lock holes  74  that are semi-circular in shape and arranged along lines  76  and  78 . Lines  76  and  78  run parallel to runners  22  and  24 . At least two peg lock holes  74  are situated along each of lines  76  and  78 . Peg lock holes  74  have straight edges  79  which are proximal to runner  24 . Between inner edge  70  and the straight edges  79  of those peg lock holes  74  in row  76  is a distance of 1½ inches. The distance between inner edge  70  and straight edges  79  of those peg lock holes  74  along line  78  is 3½ inches. Referring to  FIG. 7 , peg locks  80  have a semi-circular longitudinal cross-section  81  and are operative to engage peg lock holes  74  from above upper face  14 , and to extend past lower face  16  of platform  12 . Each of peg locks  80  have a cap  82  that is circular in shape, each cap  82  having a shoulder  84  operative to prevent peg locks  80  from falling entirely through peg lock holes  74  in platform  12 .  
         [0023]     During use, platform  12  is placed on top of a workpiece such that the workpiece is situated between runners  22  and  24 , and lower face  16  of platform  12  rests on the workpiece. Platform  12  is oriented, and guiding strips  42  and  48  are engaged with runners  22  and  24 , in accordance with the desired angle of the cut.  
         [0024]     For example, referring to  FIG. 4 , to obtain a sixty degree angle cut on workpiece end  90  of a 2×4 workpiece  88  using a hand-held power saw  92 , guiding apparatus  10  is placed over 2×4 workpiece  88  such that the ends  102  and  104  of runners  22  and  24  are proximal to workpiece end  90 . Guiding strip  48  is engaged with runners  22  and  24  by inserting peg  50  into peg hole  38  and peg  66  into peg holes  40  and  54 . Guiding apparatus  10  may be aligned with 2×4 workpiece  88  by sliding guiding apparatus  10  longitudinally along 2×4 workpiece  88 . Once 2×4 workpiece  88  is aligned and placed against edge  70  of runner  24 , 2×4 workpiece  88  is held in place by peg locks  80  inserted into peg lock holes  74  along line  78 , the multiple peg locks  74  and the straight edges  91  of peg locks  80  operative to prevent lateral movement of 2×4 workpiece  88 .  
         [0025]     Downward pressure is applied by hand onto upper face  14  of platform  12  such that lower face  16  of platform  12  engages top face  91  of 2×4 workpiece  88 , and friction between lower face  16  and top face  91  operates to hold 2×4 workpiece  88  in place against guiding apparatus  10 . Hand-held power saw  92  is aligned for the cut by resting the bottom of saw base plate  96  on runner  22  with base edge  94  of base plate  96  in contact with guiding edge  49  of guiding strip  48 . Blade  100  of hand-held power saw  92  is set in motion prior to blade  100  engaging 2×4 workpiece  88 . While keeping base edge  94  in contact with guiding edge  49  of guiding strip  48 , and base plate  96  on top of runner  22 , hand-held power saw  92  is moved in the direction along line a to engage and cut 2×4 workpiece  88 . Guiding strip  48  extends a distance beyond runners  22  and  24  sufficient to allow for a straight and accurate start and finish to the cut.  
         [0026]     A cut at an angle of one hundred twenty degrees may be obtained using guiding apparatus  10  in the same configuration as described above, but by rotating 2×4 workpiece  88  one hundred eighty degrees around its longitudinal axis. Guiding apparatus  10  is prepared for a cut at an angle of forty-five degrees (or one hundred thirty-five degrees, upon rotating 2×4 workpiece  88  one hundred eight degrees around the longitudinal axis of 2×4 workpiece  88 ) by positioning guiding strip  48  such that peg  50  engages peg hole  38  and peg  66  engages peg holes  54  and  40 . Similarly, guiding apparatus  10  may be used to obtain a cut at ninety degrees using guiding strip  42 . Multiple cuts along 2×4 workpiece  88  may be executed merely be sliding either guiding apparatus  10  or 2×4 workpiece  88  along the longitudinal axis of 2×4 workpiece  88 . Guiding apparatus  10  is designed to have few moving parts and to allow easy and quick alignment that is easily maintained during its use.  
         [0027]     Platform  12  is shaped as having five edges in order to provide a large surface area of lower face  16  for engaging a workpiece and holding the workpiece in place when downward pressure is applied to upper face  14 , while also allowing for guiding strip  48  to be positioned in two different ways to obtain angles B and C. To allow for greater friction and better positioning, lower face  16  may be either textured or coated to provide a non-abrasive non-slip surface suitable for engaging a workpiece.  
         [0028]     The extension of guiding strips  42  and  48  beyond runners  22  and  24  allows for a clean start and follow-through for the desired cut. Runners  22  and  24  provide upward support for base plate  96  to assist with guiding hand-held power saw  92  in alignment with the plane of the upper surface of a workpiece.  
         [0029]     A typical hand-held power saw  92  having a base plate  96  with a base edge  94 , and a blade  100 , has a distance between base edge  94  and blade  100  that is between 5 inches and 5/2 inches. For a hand-held power saw  92  with a distance between base edge  94  and blade  100  that is 5¼ inches, the preferred length, perpendicular to each of guiding strip  42  and guiding strip  48 , by which runners  22  and  24  extend beyond guiding strips  42  and  48  in a direction away from platform  12  is not less than 1 inch and not greater than 3½ inches. The maximum of 3/2 inches is specified to allow tilting of blade  100  up to an angle of 45 degrees to allow for a double-angled cut such as the cut as shown in  FIG. 9 . According to  FIG. 9 , workpiece  150  is cut along lines  156  on its upper surface at an angle E of sixty degrees, and along line  158  on the side edge of workpiece  150  at an angle D of forty-five degrees. Referring to  FIGS. 1 and 8 , an alternative embodiment that allows for a maximum upper surface to runners  22  and  24  while allowing for a double-cut is one in which ends  102  and  104  of runners  22  and  24 , respectively, are tapered along outside edges  103  and  105  at an angle of forty-five degrees, such that runners  22  and  24  extend beyond guiding strips  42  and  48  in a direction away from platform  12  no greater than 4/2 inches at the upper surfaces of runners  22  and  24 , and no greater than 3/2 inches at the lower surfaces of runners  22  and  24 . For hand-held power saws of different dimensions, apparatus  10  may be modified such that the dimensions of runners  22  and  24  complement the dimensions of the particular hand-held power saw.  
         [0030]     The guiding apparatus  10  may be used for workpieces of various sizes. Platform  12  may have additional peg lock holes at various distances from edge  70  of runner  24  for the purpose of holding workpieces of various widths. A 2×2 workpiece (not shown) may be cut using the peg lock holes  74  along line  76  to hold it in place. The width of guiding apparatus  10  also allows use for cutting a 2×6 workpiece (not shown) of actual dimensions 1½ inches by 5/2 inches by allowing for distance  68  of 5⅝ inches. For workpieces wider than a 2×6, guiding apparatus  10  may be designed so that distance  68  is greater than 5⅝ inches. To allow a user to hold a workpiece against either of runners  22  and  24 , additional peg lock holes (not shown) may be allowed such that the additional peg lock holes are placed at various desirable distances from runner  22 . Alternatively, rectangular peg holes (not shown) and rectangular peg locks (not shown) may be used and spaced such that each rectangular peg hole may be used to hold a workpiece against either of runners  22  and  24 .  
         [0031]     Workpieces that are of a depth less than 1½ inches, such as mouldings and trim, may be cut using guiding apparatus  10  by placing such a workpiece on a filler piece, preferably of a width equal to or approximating the distance between runners  22  and  24 , that allows the upper surface of such a workpiece to be engaged by lower face  16  of platform  12 , while also decreasing the likelihood of lateral movement of the workpiece during the execution of a cut. Alternatively, lumber that is of a depth of ¾ inches, such as 1×2, 1×4 and 1×6 pieces, may be doubled up to have one of the lumber pieces act as filler.  
         [0032]     To allow an even more secure engagement of a workpiece by peg locks  80 , peg locks  80  may be modified in design in accordance with  FIG. 6  of alternative peg  120 . Alternative peg  120  has a body  122  and head  124 . Head  124  has a shoulder  126  and extensions  128  operative to prevent alternative peg  120  from falling entirely through peg lock holes  74  in platform  12 . Extensions  128  extend outwardly from the longitudinal axis of body  122  in a direction perpendicular to the straight edges  132  of body  122  such that head  124  and body  122  share a t-shaped flat face  130 .  
         [0033]     Alternative peg  120  is operative to engage a peg lock hole  74  from above upper face  14 , and to extend past the lower face  16  of platform  12 , or, alternatively, to engage a peg lock hole  74  from lower surface  16 . When alternative peg  120  engages a peg lock hole  74  from lower surface  16 , head  124  rests on the work surface on which a workpiece rests, and t-shaped flat face  130  provides a surface operative to engage workpiece and to prevent workpiece from twisting or moving laterally during execution of a cut.  
         [0034]     Cross-sectional shapes other than those indicated above may be used for peg locks  80  (or alternative pegs  120 ) and peg lock holes  74 . For example, peg locks  80  may be cylindrical or rectangular pyramidal in shape, and peg lock holes  74  may accordingly be circular or rectangular in shape. However, it is preferable that peg locks  80  have flat faces, and, consequently, that peg lock holes  74  have a flat edges to complement peg locks  80 , as flat faces on peg locks  80  engage workpieces more securely than rounded faces, preventing a workpiece from twisting or moving laterally during the execution of a cut.  
         [0035]     There are no screws required during use of apparatus  10  and no clamps or kerfs required to hold the workpiece in place.  
         [0036]     While use of peg lock holes  74  and peg locks  80  decreases the likelihood of lateral movement, sufficient downward pressure on upper face  14  of guiding apparatus  10  also serves to keep a workpiece from moving. Distance  25  of 1⅜ inches allows for a substantial surface area on edge  70  for engaging a workpiece, while ensuring that lower face  16  may engage the upper surface of standard lumber workpieces such as 2×2, 2×4 and 2×6 pieces, which have actual depths of 1½ inches.  
         [0037]     Alternatively, apparatus  10  may be used with a work table such as the Black &amp; Decker Workmate 400 (Trademark) to facilitate holding a workpiece in place and preventing lateral movement during a cut. Referring to  FIG. 5 , the Black &amp; Decker Workmate 400 (Trademark) has a table surface  110  having perforations  112  for the insertion of accessories  114 . For example, in using apparatus  10  in conjunction with Black &amp; Decker Workmate 400 (Trademark) to facilitate a cut in 2×4 workpiece  88  at a ninety degree angle, one side of 2×4 workpiece  88  is placed against edge  71  of runner  22  while the opposite side of 2×4 workpiece  88  is placed against edges  116  of accessories  114 , and force is applied to maintain this alignment.  
         [0038]     While a uni-positional guiding strip, such as guiding strip  42 , may be more permanently attached to runners  22  and  24 , for packaging and storage purposes, it is preferred that guiding strips  42  and  48  be detachable. Guiding apparatus  10  may also be modified to allow for various other cut angles.  
         [0039]     Use of guiding apparatus  10  does not require the use of triangles, protractors and other aids for measuring angles in order to obtain straight and accurate cuts for commonly used angles. There are few components to guiding apparatus  10  allowing for ease of use.  
         [0040]     In the preferred embodiment, injection-moulded plastic would be used to make a durable, light-weight, inexpensive and precision-crafted guiding apparatus  10 . Alternatively, guiding apparatus  10  may be made of wood such that platform  12  is firmly secured to runners  22  and  24  using, for example, screws or nails and that pegs  44 ,  46 ,  50  and  52  are attached using, for example, glue or nails to upon insertion them into bored holes (not shown) in guiding strips  42  and  48 . While guiding apparatus  10  may also be constructed using metal, a balance would have to be reached between the rigidity of the metal, to ensure guiding apparatus  10  holds its shape, and the weight of guiding apparatus  10 , to ensure that guiding apparatus  10  is not too heavy and that its portability is not unduly impacted.  
         [0041]     This invention has been described with reference to illustrative embodiments, rather than restrictive embodiments. Accordingly, this description is not intended to be construed in a limiting sense. Various modifications to the illustrative embodiments, as well as other embodiments of the invention, will be apparent to a person skilled in the art upon reference to this description. The scope of the invention is indicated by the appended claims rather than the foregoing description and all such modifications or embodiments that come within the meaning and range and equivalence thereof are intended to be embraced therein.