Abstract:
A blade sharpening device is provided for honing a cutting edge of a blade. The device includes a block with a top honing surface, and a jig assembly mounted on the block. The jig assembly holds a blade in a fixed position adjacent the honing surface, and directed towards the honing surface, so that a sharpening stone can be manually moved on the top honing surface and across the blade edge for sharpening. The stone can be moved longitudinally, laterally, and circularly. The jig assembly is pivotally mounted on the block for a desired sharpening angle, and vertically adjustable so that the blade edge is substantially flush with the top honing surface of the block.

Description:
FIELD OF THE INVENTION 
   This invention relates to a device for sharpening blades of cutting tools using a whetstone, and particularly a jig for holding various woodworking edge tools, such as planes, chisels, scrapers, and the like. 
   BACKGROUND OF THE INVENTION 
   Cutting tools require a sharp edge to function satisfactorily and efficiently. Typically, the tool blade has a beveled cutting edge defined by two intersecting angles. The more refined or smoother the angle intersection can be made, the sharper the tool will be. Also, the more consistently that the angle can be made from one sharpening operation to the next sharpening operation, then the faster the desired edge can be obtained. A sharpening jig aids in setting the angle of the beveled edge repeatedly and accurately each time the blade is sharpened. 
   Prior art sharpening jigs are typically slow to set up or cumbersome to use. Prior art jigs usually have no provision or accommodation for setting the angle, except by using a separate angle measuring device. Using the blade jig in combination with the separate angle registration device takes time, and is prone to error. It is also awkward and difficult to secure the tool blade on the jig at the desired angle in many prior art sharpening devices. 
   It is normally desirable to hone both the beveled edge of the blade and the back side of the blade. However, with prior art jigs, only a small portion of the back side of the blade normally projects from the jig. Therefore, only a small portion of the back side of the blade which protrudes from the jig can be polished with the sharpening stone. For short bladed tools, the typical jig does not work, because the tool handle prevents the blade from protruding sufficiently so as to hone the required angle. 
   Some jigs utilize a roller which rolls on the sharpening stone while the blade is being honed. The distance from this roller to the blade edge may be long, depending on the bevel angle, which thus requires the sharpening stone to be longer than would otherwise be necessary so that the roller remains on the stone during the sharpening process. 
   Therefore, a primary objective of the present invention is the provision of an improved blade sharpening device. 
   Another objective of the present invention is the provision of a blade sharpening device which fixes the tool blade in a stationary position while the sharpening stone moves over the blade. 
   Still another objective of the present invention is the provision of a blade sharpening device having a scale for directly setting the honing angle. 
   Yet another objective of the present invention is a blade sharpening device having an unobstructed upper surface along which the sharpening stone moves over a blade edge in lateral, longitudinal, and/or circular motions. 
   A further objective of the present invention is the provision of a blade sharpening device which minimizes the sharpening stone size. 
   Another objective of the present invention is the provision of a blade sharpening device wherein the blade is referenced on its back side, with the beveled edge facing upwardly. 
   Still another objective of the present invention is the provision of a blade sharpening device having improved visibility during the sharpening process. 
   Still another objective of the present invention is the provision of a blade sharpening device which can hone both angled and straight blade edges. 
   A further objective of the present invention is the provision of a blade sharpening device which can be used for very small blades. 
   Yet another objective of the present invention is the provision of a blade sharpening device having an internal storage compartment for sharpening stones and other accessories. 
   Another objective of the present invention is the provision of an improved blade sharpening device which can sharpen blades repeatedly and accurately. 
   Still another objective of the present invention is the provision of a blade sharpening device which can be used to sharpen scraper blades at true 90° angles. 
   A further objective of the present invention is the provision of a blade sharpening device having a waterproof jig for water-stone sharpening. 
   Another objective of the present invention is the provision of an improved blade sharpening device which is economical to manufacture, and durable and efficient in use. 
   These and other objectives will become apparent from the following description of the invention. 
   BRIEF SUMMARY OF THE INVENTION 
   The blade sharpening device of the present invention includes a block with opposite first and second ends, opposite sides, and a top surface. A jig assembly is amounted in one end of the block and is adapted to hold various blades to be sharpened in a fixed position, with the edge of the blade being adjacent to and substantially flush with the top surface of the block. A sharpening stone is slid manually along the top surface of the block in longitudinal, lateral, and/or circular motions over the blade, so as to the sharpen cutting edge of the blade. 
   The jig assembly is pivotally mounted on the block such that the angle of the blade relative to the top surface of the block is adjustable. The jig is also vertically adjustable relative to the top surface of the block so that the blade is substantially flush with the top surface. A scale is provided on the block, with a pointer connected to the jig assembly to directly indicate on the scale the angle of the jig. A second jig assembly may be provided on the block to hold a scraper blade for sharpening the blade edge at a 90° angle. The block is hollow so as to define a storage compartment therein for storing sharpening stones and other accessories. 
   The method of sharpening a blade using the device of the present invention comprises the steps of fixing the blade in the jig so as to be stationary with the edge of the blade facing the top support surface of the block, manually gripping a sharpening stone in a user&#39;s hand, and moving the sharpening stone along the support surface so as to hone the edge of the blade. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the blade sharpening device of the present invention. 
       FIG. 2  is another perspective view of the blade sharpening device. 
       FIG. 3  is a side elevation view of the device. 
       FIG. 4  is an end elevation view of the device. 
       FIG. 5  is an enlarged perspective view of the jig assembly of the device. 
       FIG. 6  is a view from an opposite end showing the internal storage compartment of the device. 
       FIG. 7  is another perspective view of the device showing a blade from a plane secured to the jig for sharpening. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The blade sharpening device of the present invention is designated by the reference numeral  10  in the drawings. The device  10  generally comprises a block  12  and a jig assembly  14  mounted to the block. 
   The block  12  includes opposite sides  16 ,  18 , a top surface  20 , and opposite ends  22 ,  24 . Preferably, a bottom  26  is also provided on the block  12 . Preferably, the block  12  is hollow, with the front end  22  comprising a wall and the rear end  24  comprising a door so as to define an internal storage compartment  28  for storing sharpening stones, extra blades, and other accessories. The door  24  may be pivotally connected to the block  12  in any convenient manner so as to be moveable between open and closed positions to provide access to the storage compartment  28 . For example, as seen in  FIG. 3 , the door  24  is mounted to the block  12  by a pivot pin  30  and is retained in a closed position via the pressure of a thumb screw  32 . It is understood that the door  24  can also be hinged to the block  12  and have any conventional latch or lock mechanism to maintain the door in the closed position. 
   The jig assembly  14  includes a jig body  34  which is pivotally mounted between the left and right sides  16 ,  18  of the block  12  on a pivot axis defined by axles  36 ,  38  extending from opposite sides of the body  34 , as best seen in  FIG. 4 . While  FIG. 4  shows the axles  36 ,  38  to be separate, it is understood that a single, elongated axle can extend through the length of the body  34 , as opposed to separate axles. The left axle  36  extends outwardly beyond the left side wall  16 . A clamping knob  40  is threadably mounted on the outer end of the axle  36 . The knob  40  can be loosened to allow pivotal rotation of the jig body  34 , and can be tightened so as to fix the jig body  34  in a selected angular position. 
   The right axle  38  extends outwardly beyond the right side wall  18 , and has a pointer  42  attached to the outer end of the axle  38 . A scale  44  is secured in any convenient manner to the right side wall  18  of the block  12  and includes angular indices corresponding to the angular orientation of the jig body  34 . Thus, as the body  34  is pivoted about the axles  36 ,  38 , the pointer  42  directly indicates on the scale  44  the angular orientation of the jig body  34 . 
   The jig body  34  is also vertically adjustable relative to the top surface  20  of the block  12 . More particularly a pair of threaded posts or shafts  46  are mounted in grooves  48  on the inside of the side walls  16 ,  18 , as best seen in  FIG. 4 . At the top of each post  46  is a shaft collar  50  with a bushing through which the axles  36 ,  38  extend. The bottom of each post  46  is threadably received in a wheel  52 . The shaft collars  50  do not rotate, but are free to slide along the enlarged upper end of the grooves  48 , thereby allowing the axles  36 ,  38  and the jig body  34  to be adjusted upwardly and downwardly along the axle slots  39  in the block side walls  16 ,  18  as the wheels  52  are rotated. 
   The jig body  34  includes a T-shaped slot  54  extending across the width of the body. A pair of nuts  56  are retained within the T-shaped slot  54 . A pair of blade stops  58 ,  60  are mounted on the jig body  34  by bolts or thumb screws  62  extending through slots  64 ,  66  in the blade stops  58 ,  60 , respectively and into the nuts  56  in the T slot  54 . The blade stops  58 ,  60  are adapted to hold or clamp a blade to be sharpened on to the upper surface  68  of the jig body  34 . A second slot  70  is provided on the blade stop  60  and has a countersink. A screw  74  with a countersink head extends through the slot  70  and into a nut in the T-slot  54 . The T-slot  54  allows lateral adjustment of the space between the blade stops  58 ,  60 , so as to accommodate blades  76  having different widths positioned between the blade stops  58 ,  60 , as shown in  FIG. 7 . The screw  74  can be tightened with a screwdriver so that the countersink head of the screw  74  wedges the side of the blade stop  60  slightly outwardly so as to secure the blade  76  between the blade stops  58 ,  60 . Thus, the male and female countersinks of the slot  70  and screw  74  have a wedging effect. When the screw  74  is released, the blade  76  can be removed from the jig body  34 . The slots  64 ,  66  in the blade stops  58 ,  60  allow longitudinal adjustment of the blade stops, so as to accommodate smaller blades  78  to be positioned in front of the blade stops  58 ,  60  for sharpening, as shown in  FIG. 2 . 
   In use, the angle to be honed on the blade  76 ,  78  is set on the jig body  34  by loosening the lock knob  40 , turning the body  34  to the desired angle as indicated by the pointer  42  on the scale  44 , flushing the body  34  with the top honing surface  20  of the block  12  by turning the body height adjusting wheels  52  to move the body  34  upwardly or downwardly via the axle slots  39 , and then tightening the knob  40 . The blade  76 ,  78  is set onto to the upper surface  68  of the body  34  with the beveled side up so that the cutting edge  80  is directed towards the top surface  20  of the block  12 . The blade edge  80  will be very slightly positioned above the honing surface  20 . During an initial honing or sharpening procedure wherein a bevel may need to be re-made or increased honing pressure is necessary, the blade is preferably clamped between the blade stops  58 ,  60 , and the outer thumb screws  62  tightened, as shown in  FIG. 7 . Then, the clamping screw  74  is tightened to further secure the blade between the stops  58 ,  60 . 
   For subsequent honing with finer grit stones, it is unnecessary to clamp the blade between the stops  58 ,  60 . Rather, the blade can be positioned between or in front of the stops  58 ,  60  and held by hand. This hand retention of the blade on the jig body  34  provides for fast and convenient “chasing of the wire edge” by flipping the blade between the beveled edge  80  and the back side. The blade is set on the top surface of the block  12  with the back side facing upwardly when the back side is being honed. 
   The stops  58 ,  60  have forward edges ground at a 45° angle, which allows short and/or thin blades to be positioned in front of the stops  58 ,  60 , which are then adjusted forwardly and rearwardly via the slots  64 ,  66  and the thumb screws  62  so that the blade edge is substantially flush with the top surface  20  of the block  12  for sharpening. By capturing the rear of the short or thin blade  78  in the beveled front edge of the stops  58 ,  60 , the blade is effectively held for honing, and is easily removed and repositioned. 
   One of the side walls  16 ,  18  of the block  12  has two additional blade stops  82  secured to the side wall with thumb screws  84  extending through slots  86  in the stops  82 , and received in threaded inserts tapped into the side wall of the block  12 . A scraper blade, also known as a card scraper, can be set in the blade stops  82 , which are vertically adjusted via the slots  86 , such that the edge of the scraper  88  is very slightly above the honing surface  20  of the block  12 , so as to allow for quick and accurate sharpening of the scraper edge, and assuring a 90° angle on the edge. 
   The top honing surface  20  of the block  12  is free from obstructions, such that the sharpening stone  90  can be slid on the top surface  20  in a longitudinal motion, lateral motion, and/or circular motion on the surface  20  and across the blade edge  80  for sharpening. 
   The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.