BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the present invention.
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.
FIG. 3 is a side view of the present invention showing the body and roller members.
FIG. 4 is a perspective view of the present invention showing the fastening plate of the adjustable clamp component.
FIG. 5 is a side view of the present invention showing the fastening plate and the concave tool-engaging surface.
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.
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.
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
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.
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.
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.
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.
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 28a 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.
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 28a 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.
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.
FIG. 5 is a side view of fastening plate 32 shown in FIG. 4. Top plate surface 33 includes an optional fastener recess 33a for receiving the engaging end of adjustable fastener 38. Optional fastener recess 33a 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 33a, 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 34a, which are more clearly shown in FIG. 6.
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 34a, which are preferably formed in bottom plate surface 34. Optional bottom plate grooves 34a 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 34a, 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 34a is 1/32 in.
FIG. 7 illustrates the use of the present invention with a planing blade 1 mounted in sharpening holder 10 on a honing surface 2a 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 1a facing towards the honing stone surface 2a. The blade 1 and sharpening holder 10 are adjusted so that cutting edge 1a contacts honing stone surface 2a. 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 1a on honing stone surface 2a in the directions indicated by arrows 100.
Unlike prior art hand or manual sharpening tools and jigs, the present invention moves the cutting edge 1a in a motion that is parallel to the cutting edge 1a and not perpendicular. The advantage of the sharpening holder 10 and its method of sharpening is that the entire honing stone surface 2a can be used. Cutting edge 1a can be moved to and beyond the edges 2b 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 2a. In fact, it is typical that the honing stone surface 2a 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 1a 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.
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 2a so that cutting edge 1a makes contact with honing stone surface 2a. The distance between the cutting edge 1a and the plurality of roller members 40 depends on the bevel angle of the cutting edge 1a. 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°.
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 1a 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.
It is also noted that the distance the cutting edge 1a 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 2a. 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.
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.
Patent Application
20080064309
