Patent Abstract:
A sharpening holder for manually-sharpening a cutting edge to be honed over a honing surface includes a body, an adjustable clamping component, and a plurality of roller members. The body has a first end, a second end and a tool support surface between the first end and the second end. The adjustable clamping component has a fastening plate positioned against the tool support surface. The fastening plate has a tool engaging surface to hold the tool against the tool support surface. The plurality of roller members are attached to a lower portion of the body adjacent the second end where the plurality of roller members are configured to allow the body to roll in a direction selected from the group consisting of sideways and in an arc on the honing surface causing the cutting edge of the tool to move parallel to the honing surface instead of perpendicular to the honing surface.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to tool holders. Particularly, the present invention relates to blade sharpening holders. More particularly, the present invention relates to honing guides and tool grinding rests. 
         [0003]    2. Description of the Prior Art 
         [0004]    When sharpening a cutting edge on a tool, it was common to use jigs to hold the tool to be sharpened at a predetermined angle to a grind stone. Typically, the grind stones were water cooled. The grinding jigs usually included a roller which supported a plate upon which the tool was secured. The support plate and roller held the tool at a selected angle against the stone surface. As the stone was moved, the cutting edge was ground to the selected angle. The initial setting of the tool in the jig was critical to the success of the operation. 
         [0005]    The present use of such guides is now customarily limited to flat bench stones. The skilled artisan, however, differentiates between grinding and honing. Grinding is considered as defining the basic edge and honing as refining the basic edge to the finished sharp edge. In the normal sharpening process, the edge to be sharpened is initially passed over the coarse stone at a selected angle. This process leaves a ragged edge of the desired angle. The bevel is then refined over a stone of finer particles. Since such stones cut more slowly, the work is done on the part of the bevel which intersects with the face of the tool to provide a micro-bevel. 
         [0006]    The micro-bevel selected should be a function of the tool material, the material to be cut and the intended use. Ideally, the bevel angle should be no greater than is necessary to prevent the edge from breaking down so that the wedging action of the tool is minimized as the edge enters the material to be cut. 
         [0007]    When manually sharpening a tool&#39;s cutting edge, the skilled artisan uses a honing stone that is typically rectangular shaped. A small amount of honing oil, which is a lightweight oil, is usually placed on the honing stone. The skilled artisan then pulls or pushes the cutting edge over the honing stone at the desired angle as if the cutting edge were scrapping the surface of the honing stone, i.e. the cutting edge is pushed or pulled over the honing surface in a perpendicular fashion. Several blade holders to facilitate manual sharpening of a cutting edge over a honing surface have been devised. 
         [0008]    U.S. Pat. No. 4,733,501 (1988, McLean) discloses a honing guide. The honing guide includes a tool support plate mounted above a surface-engaging roller. The surface engaging roller is mounted eccentrically so that the height of the tool support plate may be varied to provide a range of honing angles without unclamping the tool from the guide. 
         [0009]    U.S. Pat. No. 5,472,375 (1995, Pugh) discloses a blade sharpening angle guide. The blade sharpening guide includes an elongated curved block having a longitudinal slot therethrough. The longitudinal slot releasably holds a knife blade with the blade cutting edge extending a distance outside the slot. 
         [0010]    U.S. Pat. No. 6,030,281 (2000, Cozzini et al.) discloses a sharpening apparatus. The sharpening apparatus includes a base member on which a sharpening stone is positioned. A slidable blade guide member is slidably connected to the base member and includes a guide surface that is disposed at an angle relative to the upper surface of the sharpening stone and a mounting mechanism for removably mounting a spatula against the guide surface such that the scraping edge of the spatula is in engagement with the sharpening stone. The slidable blade guide member is manually slidable back and forth to sharpen the scraping edge of the spatula. A fixed blade guide member is also attached to the base member. The fixed blade guide member includes a horizontal slot that is adapted to receive the shaft of a grill scraper. The fixed blade guide member is adapted to provide guided back and forth sliding movement of the grill scraper within the slot and engagement with the sharpening member to sharpen the scraping edge of the grill scraper. 
         [0011]    The above-described devices require the cutting edge of the tool to move over and against the sharpening/honing stone in a “scraping” motion. In other words, the motion of the cutting edge to the stone surface is similar to the action used with a scraper/tool. A disadvantage of this type of action is that the honing stone surface develops a concave shape with use thus shortening the useful life of the honing stone. Another disadvantage is that the concave surface of the honing stone produces a cutting edge that is inconsistent since the cutting edge angle changes as the cutting edge moves through the concavity in the stone surface. Yet another disadvantage is that only a portion of the honing stone is used since the holder must be on the stone at the beginning of the honing process in order to insure that the cutting edge is positioned correctly relative to the honing surface. 
         [0012]    Therefore, what is needed is a sharpening holder for use in manually sharpening a cutting edge that does not cause the development of a concave surface in the honing stone with extended use. What is further needed is a sharpening holder that allows the use of substantially the entire surface area of the honing stone. What is also needed is a sharpening holder that does not use a “scrapping” action of the cutting edge over the honing surface in order to sharpen the cutting edge. 
       SUMMARY OF THE INVENTION 
       [0013]    It is an object of the present invention to provide a sharpening holder that allows a user to use substantially the entire surface area of the honing stone surface when manually honing a cutting edge. It is another object of the present invention to provide a sharpening holder that does not cause the development of a concave honing surface in a honing stone when a cutting edge is sharpened using the sharpening holder. It is a further object of the present invention to provide a sharpening holder that does not rely on “scrapping” the cutting edge into the honing surface to achieve sharpening of the cutting edge. 
         [0014]    The present invention achieves these and other objectives by providing a sharpening holder that has a body, an adjustable clamping component, and a plurality of roller members. The body has a first end, a second end and an opening through the body between the first end and the second end, and the opening has a tool support surface. The adjustable clamping component has a fastening plate positioned within the opening of the body. The fastening plate has a tool engaging surface to hold the tool to be sharpened against the tool support surface of the body. The plurality of roller members are attached to a lower portion of the body below the opening and adjacent the second end where the plurality of roller members are configured to allow the body to roll sideways on the honing surface causing the cutting edge to move parallel to the honing surface instead of perpendicular to the honing surface. The plurality of roller members may also be configured to allow the body to roll through an arc on the honing surface to provide “parallel” like sharpening of a curved cutting edge. 
         [0015]    The adjustable clamping component also includes an adjustable fastener for holding the fastening plate against the tool/blade inserted in the opening of the body. The plurality of roller members is attached to a lower portion of the body below the opening and adjacent the second end of the body. The plurality of roller members may be permanently attached or, preferably, removably attached. Optionally, a raceway may be used to house the plurality of roller members. The raceway is preferably formed at a angle to the bottom of the body and may be incorporated into a body extension that extends below the body adjacent the second end. It should be noted that the use of a raceway is optional, especially when wheels or cylindrical rollers or tapered rollers are used since these could be attached to an angled surface on the bottom of the body or at the second end of the body. If a body extension is used, the body extension may be integrally formed with the body or may be a separate component that is attached to the body. 
         [0016]    The unique feature of the present invention is the ability to sharpen the cutting edge of a blade or tool using a sideways motion with the sharpening holder that is parallel to the cutting edge of the blade or tool when manually sharpening a tool on a stationary honing stone surface. The prior art devices require a sharpening motion that is perpendicular to the cutting edge. The parallel sharpening motion has the added advantage that it does not create a concavity in the honing stone surface with use over time like that created by prior art devices. 
         [0017]    Another feature of the present invention is the relationship of the cutting edge of a tool/blade mounted in the body to the plurality of roller members. The plurality of roller members is positioned preferably at a predetermined angle to the bottom of the body so that the distance between the cutting edge to be sharpened and the points of contact of the roller members with the honing stone surface is less than one-half the width of the honing stone. This feature provides another advantage of the present invention in that it allows sharpening over substantially the entire honing stone surface. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view of the present invention. 
           [0019]      FIG. 2  is a front view of the present invention showing the blade receiving opening in the body of the sharpening holder with the plurality of roller members. 
           [0020]      FIG. 3  is a side view of the present invention showing the body and roller members. 
           [0021]      FIG. 4  is a perspective view of the present invention showing the fastening plate of the adjustable clamp component. 
           [0022]      FIG. 5  is a side view of the present invention showing the fastening plate and the concave tool-engaging surface. 
           [0023]      FIG. 6  is a bottom view of the fastening plate of the present invention showing the plurality of tool-holding grooves in the tool-engaging surface. 
           [0024]      FIG. 7  is a perspective view of the embodiment of the present invention in  FIG. 1  showing the positioning of the sharpening holder with a cutting edge on a honing surface. 
           [0025]      FIG. 8  is a side view of the embodiment of the present invention in  FIG. 7  showing the positioning of the sharpening holder with a cutting edge on a honing surface. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    The preferred embodiment(s) of the present invention is illustrated in  FIGS. 1-8 .  FIG. 1  shows the sharpening holder  10  of the present invention with one type of blade  1  mounted for sharpening. Sharpening holder  10  has a body  20 , an adjustable clamping component  30 , and a plurality of roller members  40 . Body  20  has a first end  22 , a second end  23  and an opening  24  through body  20  between first end  22  and second end  23 . Body  20  also includes a tool support surface  25  within opening  24 . 
         [0027]    Adjustable clamping component  30  includes a fastening plate  32  and an adjustable fastener  38 . Adjustable fastener  38  engages fastening plate  32  and imparts a holding force so that fastening plate  32  secures the cutting blade  1  to the tool support surface  25 . Although various adjustable fasteners may be used to engage fastening plate  32 , adjustable fastener  38  is preferably a thumb screw that engages fastening plate  32  through a threaded opening  27  in a top surface  26  of body  20 . 
         [0028]    The plurality of roller members  40  are connected to a lower portion  28  of body  20  below opening  24  and adjacent to second end  23 . Each of the plurality of roller members  40  are freely rotatable and are aligned to provide body  20  with a sideways rolling action. Roller members  40  that are usable in sharpening holder  10  include wheels, ball bearings, cylindrical rollers, tapered rollers, and the like. An important feature of the plurality of roller members  40  is that the roller members  40  must be sufficiently exposed to allow body  20  to not only roll sideways but also to allow body  20  to pivot through a selected angular range with the pivot point being the points of contact of the roller members  40  with a honing surface of a honing stone (not shown). It should be understood that second end  23  of body  20  may extend to up to and beyond roller members  40  a reasonable distance, if desired, without affecting the functionality of the present invention. 
         [0029]    Turning now to  FIG. 2 , there is illustrated a front view of the present invention. Opening  24  of body  20  and fastening plate  32  may be sized to accommodate a variety of blades and tools having a cutting edge. The plurality of roller members  40  are positioned within a raceway  29  that extends along the width of body  20 . The number of roller members  40  connected to body  20  depends on the size of the roller members  40  and the size of body  20 , which, in turn, is dependent on the type and size of the blade or tool with a cutting edge that is going to be sharpened and the size of the honing stone surface. The width of body  20  should be shorter than the sharpening surface to allow sufficient sideways sharpening motion. The number of roller elements  40  used is chosen to provide stability to body  20  when it is engaged with the sharpening surface in the sideways sharpening motion. In the preferred embodiment, wheels are the roller members of choice. 
         [0030]      FIG. 3  shows a side view of sharpening holder  10 . As can be seen, the preferred embodiment has body  20  with a body extension  21  that extends from lower portion  28  below opening  24  adjacent second body end  23 . Raceway  29  is located in body extension  21 . Each roller member  40  is supported by an axle  42  and all roller members  40  protrude out of raceway  29  a predefined distance. Body extension  21  is structured to have a preset angle θ relative to the bottom  28   a  of body  20 . Angle θ is preferably in the range of about 105° to about 125°. Even though body extension  21  is shown as being integral to body  20 , body extension  21  may be a separate component that is attached to body  20 . 
         [0031]    It is important to note that body  20  does not require the use of body extension  21 . Raceway  29  could easily be formed into bottom  28   a  adjacent second end  23  at the preset angle θ. The only difference is that body  20  would be slightly heavier due to a thicker bottom portion  28  in order to accommodate raceway  29 . 
         [0032]    Turning now to  FIG. 4 , there is illustrated a perspective view of fastening plate  32 . Fastening plate  32  is sized to fit within opening  24  with the blade/tool to be sharpened. Fastening plate has a top plate surface  33  and a bottom plate surface  34 . Top plate surface  33  is engaged by adjustable fastener  38  while bottom plate surface  34  is the tool engaging surface to secure the blade or tool within the sharpening holder  10 . 
         [0033]      FIG. 5  is a side view of fastening plate  32  shown in  FIG. 4 . Top plate surface  33  includes an optional fastener recess  33   a  for receiving the engaging end of adjustable fastener  38 . Optional fastener recess  33   a  prevents fastening plate  32  from inadvertently sliding while engaged by adjustable fastener  38 , especially when a blade/tool is being sharpened. Bottom plate surface  34  also includes an optional tool engaging recess  35 , which is preferably a V-shaped recess formed in bottom plate surface  34 . Similar in purpose to optional fastener recess  33   a , tool engaging recess  35  prevents the blade/tool from slipping sideways when the sharpening is being performed. Bottom plate surface  34  may also include a plurality of optional bottom plate grooves  34   a , which are more clearly shown in  FIG. 6 . 
         [0034]    Turning now to  FIG. 6 , there is shown a bottom view of fastener plate  32 . Bottom plate surface  34  has a plurality of optional bottom plate grooves  34   a , which are preferably formed in bottom plate surface  34 . Optional bottom plate grooves  34   a  also enhance the holding capability of fastener plate  32 . The edges of the blade/tool to be sharpened preferably rest within the bottom plate grooves  34   a , which further restricts any sideways movement of the blade/tool being sharpened. It has been found that the preferred spacing of optional bottom plate grooves  34   a  is 1/32 in. 
         [0035]      FIG. 7  illustrates the use of the present invention with a planing blade  1  mounted in sharpening holder  10  on a honing surface  2   a  of a honing stone  2 . Planing blade  1  is placed through opening  24  below fastening plate  32  so that blade  1  rests upon tool support surface  25  with the bevel cutting edge  1   a  facing towards the honing stone surface  2   a . The blade  1  and sharpening holder  10  are adjusted so that cutting edge  1   a  contacts honing stone surface  2   a . Fastener  38  is then turned to secure blade  1  in sharpening holder  10 . Once secured, sharpening of blade  1  is accomplished by rolling the sharpening holder  10  with the cutting edge  1   a  on honing stone surface  2   a  in the directions indicated by arrows  100 . 
         [0036]    Unlike prior art hand or manual sharpening tools and jigs, the present invention moves the cutting edge  1   a  in a motion that is parallel to the cutting edge  1   a  and not perpendicular. The advantage of the sharpening holder  10  and its method of sharpening is that the entire honing stone surface  2   a  can be used. Cutting edge  1   a  can be moved to and beyond the edges  2   b  of honing stone  2  without sharpening holder falling off of honing stone  2 . This motion and sharpening technique also eliminates the formation of a concavity in the honing stone surface  2   a . In fact, it is typical that the honing stone surface  2   a  will develop a slight convex nature when tool sharpening is performed using a sharpening holder of the present invention, which is not detrimental to the cutting edge  1   a  or the useful life of the honing stone. In fact, this “parallel” sharpening technique lengthens the useful life of the honing stone compared to stones where a sharpening jig that relies on a “perpendicular” sharpening technique is used. 
         [0037]    Turning to  FIG. 8 , there is a side view of the embodiment in  FIG. 7 . Sharpening holder  10  is pivoted about the contact point of the roller members  40  with honing stone surface  2   a  so that cutting edge  1   a  makes contact with honing stone surface  2   a . The distance between the cutting edge  1   a  and the plurality of roller members  40  depends on the bevel angle of the cutting edge  1   a . The bevel angle is normally within a range between a knife blade and a scraper. The range is typically between about 21° (knife edge) and 32° (scraper). For wood planing blades, the bevel angle is about 27°. 
         [0038]    As previously mentioned, sharpening holder  10  can be sized for the type of tool or blade that is to be sharpened as well as the size of the honing stone surface. The sharpening holder  10  is preferably structured so that the distance “d” illustrated in  FIG. 8  between the plurality of roller members  40  and the cutting edge  1   a  is less that one-half of the honing stone width. This allows the entire surface of the honing stone  1  to be used for sharpening, which in turn allows the entire surface of the honing stone  1  to wear evenly and to avoid the wear concavity caused by prior art sharpening holders and jigs. 
         [0039]    It is also noted that the distance the cutting edge  1   a  extends out of sharpening holder  10  can also change the pivoting angle of sharpening holder  10  along the contact points of the plurality of roller members with the honing stone surface  2   a . This allows the sharpening holder  10  to be used to sharpen blades or tools with cutting edges that differ from one blade or tool to another. The allowed pivoting angle of sharpening holder  10  is directly related to the size of the plurality of roller members  40  as well as the distance the roller members  40  extend from sharpening body  20 . 
         [0040]    Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.

Technology Classification (CPC): 1