Patent Publication Number: US-2015075674-A1

Title: Apparatus for Forming Dovetail and Box Joints

Description:
This application is based upon U.S. Provisional Application Ser. No. 61/959,527 filed Aug. 27, 2013, the complete disclosure of which is hereby expressly incorporated by this reference. 
    
    
     BACKGROUND 
     Dovetail joints are considered to be the hallmark of a master woodworker who has acquired a significant level of skill. Dovetail joints are also a mark of quality and attention to detail that many people look for in high-quality furniture. This is because a dovetail joint requires very accurate and consistent workmanship in order to fit together properly. However, creating tight-fitting, accurate dovetail joints requires skill and patience sometimes beyond the amateur woodworker. Existing templates/jigs for creating dovetail joints are expensive and difficult for the amateur woodworker to use. 
     One difficulty in cutting dovetails using existing templates is centering the wood workpiece on the template to ensure the ends are even. It is desirable to center the edges of the workpiece behind portions of the jig during the cutting operation. However, existing jigs are made of opaque materials such as metal thereby limiting the woodworker&#39;s ability to see the ends of the workpiece behind the jig. 
     Another difficulty in cutting dovetails joints using existing templates is that significant care must be taken to ensure the correct side of the wood workpiece is facing the template. If the workpiece is facing the wrong direction then the angles of the cuts will be backwards resulting in a workpiece that does not fit properly with the adjoining wood workpiece. Existing dovetail jigs require opposite sides of the workpiece to be facing the template when cutting the pins and tails in the wood workpiece. The action of flipping the workpiece over when making these two cuts often results in confusion and mistakes since it can be difficult to keep track of which side of the wood should be facing the template for which particular cut. 
     Thus, there is a need for an improved device which simplifies the creation of dovetail and other types of joints for woodworkers. 
     SUMMARY 
     The present invention comprises a device for assisting with the formation of dovetail joints, box joints, and other similar types of joints with a router. The device comprises a base which is adapted, to be removably combined with a jig/template. In one embodiment the template is transparent thereby allowing the user to see the wood workpiece through the template. The template has a tail side and a pin side. The tail side comprises a plurality of spaced parallel notches adapted to guide a router having an angled tail bit along the workpiece to create the tails. The pin side has a plurality of notches with sides angled such that each notch is wider toward the bottom of the notch (away from the edge of the template). The shape of the pin side notches allows a wood workpiece to face the same direction during the cutting of the pins and the tails. The pin side is adapted to guide a router having a straight bit along the workpiece to create the pins. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the base; 
         FIG. 2  is a perspective view of the base combined with the template; 
         FIG. 3  is a top view of the template; and 
         FIG. 4  is a perspective view of the tail side of the device aligned with a wood workpiece. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention, consisting of multiple embodiments and described more fully below, comprises a device which acts as a guide for a router bit to cut pins and tails on the edges of boards so the workpieces can be connected by a dovetail joint, a box joint, or other similar types of joints. As shown in  FIGS. 1-4 , the device comprises a base  101  which is adapted to be removably combined with a jig/template  105 . The base  101  provides support for the template  105  and contains significant surface area on which to clamp the device to the wood workpiece  130 . The device may be adjusted so as to accommodate differing thicknesses of the workpieces  130 . In one embodiment, the base  101  is a generally rectangular block. The base is sufficient in diameter to allow enough surface area to permit a clamping device to firmly secure the workpiece  130  to help prevent inadvertent movement. A commercially available clamp (not shown) of appropriate size is used to squeeze the workpiece  130  firmly against the base  101 . The base  101  may include notched recesses  118  along one or two of its sides. As shown in  FIG. 2 , these recesses  118  correspond to the area directly behind the notches  107 ,  109  in the template  105  to help prevent contact between the router bit and the base  101  during cutting operations. The base  101  also includes a row of openings  116 ,  120  along its top surface which are adapted to receive fasteners, such as screws. The openings  116 ,  120  are further describe below with reference to the adjustment means feature. 
     As shown best in  FIG. 3 , the template has a tail side  106  and a pin side  108 . The tail side  106  comprises a plurality of spaced parallel notches  107  adapted to guide a router having an angled tail bit along a workpiece  130  to create the tails. In one embodiment, the notches  107  have sides which are generally parallel to each other, such as a square or rectangular shape. The pin side  108  has a plurality of notches  109  with sides angled such that each notch is wider toward the bottom of the notch  109  (away from the edge of the template  105 ). In one embodiment, the sides of each notch  109  angle outward toward the sides of the device (starting at the edge  108 ) at between about 5-10 degrees. In one embodiment the sides angle outward at about 7 degrees. The pin side  108  is adapted to guide a router having a straight bit along the workpiece  130  to create the pins. The shape of the pin side  108  notches  109  (being wider at the bottom) allows the same side of the wood workpiece  130  to face the template  105  during the cutting of the pins and the cutting of tails. 
     As shown best in  FIG. 3 , one embodiment includes an adjustment means for adjusting the position of the template  105  relative to the base  101 . The adjustment means allows the user to adjust the size of the pins by changing the amount of material removed from the workpiece  130  with the router. The user adjusts the position of the template  105  for the thickness of the wood workpiece  130 . The base  101  contains a generally straight row of spaced openings  116  along the length of its top surface. The template  105  contains a row of spaced openings  114  diagonally aligned (angled relative to the length of the template  105 ), each of the openings  114  in the template  105  is adapted to correspond to one of the openings  116  in the base  101 . The openings  114 ,  116  are adapted to receive a fastener such as a screw to help secure the template  105  to the, base  101 . A fastener is only inserted through one pair of openings  114 ,  116  at a time. Changing the pair of openings  114 ,  116  used will change the position of the template  105  relative to the base  101 . For example, inserting a fastener through the openings  114 ,  116  nearer to the end of the template  105 /base  101  will cause the pin side  108  of the template  105  to be closer to the base  101  while inserting a fastener through the openings  114 ,  116  nearer to the middle of the template  105 /base  101  will cause the pin side  108  of the template  105  to be farther from the base  101 . This ability to adjust allows for accommodation of varying thickness of the workpieces  130 . To accommodate for a thicker workpiece  130 , the edge of the pin side  108  is positioned farther from the base  101 . To accommodate for a thinner workpiece  130 , the edge of the pin side  108  is positioned closer to the base  101 . As described in more detail below, the farther the edge of the pin side  108  is from the base  101  (by using the opening  114  closer to the middle), the looser the fit between the pins and tails because more material is removed from the pins created in the wood workpiece  130 . More material is removed because the router is allowed to cut farther into the wider portion of the notch  109 . In one embodiment, the template  105  includes visual indicators above each opening  114  to help the user determine which opening  114  should be used for a particular thickness of wood. As shown in  FIG. 3 , there may be two opposing sets of openings  114 ,  116  on the template  105  and base  101  to help secure the template  105  in place relative to the base  101 . Further, the angle of the openings  114  may be reversed such that the opening nearest to the outer edge of the template  105  is farthest from the pin side  108 . Also, the openings  114  on the template may be aligned in a straight line and the openings  116  on the base  101  may be angled to obtain the same adjustment means. 
     In one embodiment the template  105  is transparent thereby allowing the user to see the wood working piece through the template. To allow transparency, the template  105  may be made of any suitable material, including acrylic. The transparent template  105  helps with alignment of the wood workpiece  130  during the cutting operation. As shown in  FIG. 4 , the wood is secured behind the template  105 . With existing opaque templates it is only possible to see the portions of the wood which appear in the notches  107 ,  109 .  FIG. 4  shows the workpiece  130  centered such that its ends are visible through the notches  107 , however, it is often desirable to center the outer edges of the wood under the portions of the template  105  which separate and define the notches  107 ,  109 . The transparency of the template  105  allows the user to more easily align the edges of the wood even when the wood is behind the template  105 . 
     In one embodiment the template  105  includes at least one notch  110   a - 110   d  which functions as a router bit depth guide. The distance the router bit extends from the router is varied depending on the thickness of the workpiece  130 . The notches  110   a - 110   d  are different lengths measured from the outer edge of the template  105  to the bottom of each notch  110   a - 110   d.  In use, a user inserts the bit into the appropriate notch  110   a - 110   d  to determine the appropriate distance that the bit should extend from the router. In one embodiment, the notches  110   a - 110   d  are labeled with visual indicators to allow users to quickly and easily determine the proper router depth for a given thickness of wood. 
     In use, the base  101  is secured to the template  105  in the desired position depending on the thickness of the workpiece  130 . The user may user the router bit depth guide to determine the proper length the bit should extend from the router. The wood workpiece  130  is secured behind the tail side  106  and a router with an angled tail bit is used to cut the tails by following the pattern created by the notches  107 . The workpiece  130  is removed from the tail side  106  and similarly secured behind the pin side  108  with the same side facing the template  105 . The user then uses a router with a straight bit to create the pins by following the pattern created by the notches  109 . If the pins and tails do not fit together properly, for example, if the fit is too tight or too loose, then the user may adjust the position of the template  105  relative to the base  101  to cause the pins to be larger or smaller, as desired. For example, if the fit is too tight, the user can use the adjustment means to move the pin side  108  farther away from the base  101  to create larger openings between the pins. 
     Having thus described the invention in connection with the preferred embodiments thereof, it will be evident to those skilled in the art that various revisions can be made to the preferred embodiments described herein without departing from the spirit and scope of the invention. It is my intention, however, that all such revisions and modifications that are evident to those skilled in the art will be included with in the scope of the following claims.