Patent Grant
7387562
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.
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.
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's hand, and moving the sharpening stone along the support surface so as to hone the edge of the blade.
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
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
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
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
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
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.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1086239 | Stover | Feb 1914 | A |
| 2372121 | Rosenberg | Mar 1945 | A |
| 2572261 | Hardey | Oct 1951 | A |
| 4404873 | Radish | Sep 1983 | A |
| 4964241 | Conklin | Oct 1990 | A |
| 5138801 | Anthon et al. | Aug 1992 | A |
| 5195275 | McLean | Mar 1993 | A |
| 5363602 | Anthon et al. | Nov 1994 | A |
| 5431068 | Alsch | Jul 1995 | A |
| Number | Date | Country |
|---|---|---|
| 2077155 | Dec 1981 | GB |
