The present invention relates generally to a blade sharpener and, more particularly, to a sharpening device for serrated blades or blades having teeth or serrations, such as knives, saw blades and the like.
It is well known to sharpen smooth blades, such as knife blades and lawn mower blades, by manually moving the blade over a grinding wheel at a desired angle or angles to provide a sharpened edge along the blade that prolongs the useful life of the blade. For serrated blades, manually sharpening can be much more difficult to accomplish in a manner that preserves the shape of the teeth or serrations on the blade and that provides a consistent sharpened edge along the length of the blade. Accordingly, it is common for some serrated blades to be removed from an associated tool when the blade is dull and discarded to be replaced with a new serrated blade.
The present invention provides a blade sharpening apparatus and method for sharpening a serrated blade in a precise and generally consistent manner. The serrated blade is securely held in a position with a blade holder, such as a clamping device, that exposes a toothed edge of the serrated blade. A grinding wheel is provided that rotates and has a grinding edge that is shaped to engage the teeth or serrations spaced along the toothed edge of the selected serrated blade that is secured in the blade holder. An oscillating mechanism provides lateral oscillation between the blade holder and the grinding wheel at an oscillating distance that is selected to correlate with the depth between the teeth or serrations on the serrated blade. A linear actuator provides longitudinal movement between the blade holder and the grinding wheel that is substantially parallel with the rotational axis of the grinding wheel. The linear actuator is operable with the oscillating mechanism to coincide the longitudinal and lateral movements to correspond to the depth and spacing of the teeth or serrations disposed along the serrated blade, such that the serrated blade is sharpened consistently across the blade, while maintaining the teeth or serrations and overall shape of the serrated edge. Accordingly, with the use of such an apparatus and method, sharpening previously used serrated blades can prolong the useful life of a serrated blade and can be more economical than discarding and replacing dull serrated blades.
In accordance with one aspect of the present invention, a blade sharpening apparatus for sharpening a serrated blade includes a blade holder configured to securely hold a serrated blade in a position that exposes a toothed or serrated edge of the serrated blade. The blade sharpening apparatus also includes a grinding wheel that is configured to rotate about a rotational axis and engage teeth or serrations spaced along the toothed or serrated edge of the serrated blade that is secured in the blade holder. An oscillating mechanism is configured to laterally oscillate the blade holder or the grinding wheel relative to the other at an oscillating distance greater than a depth between the teeth or serrations on the serrated blade. A linear actuator is coupled with one of the blade holder and the grinding wheel and configured to longitudinally move substantially parallel with the rotational axis of the grinding wheel. The linear actuator is operable with the oscillating mechanism to coincide the longitudinal and lateral movement to correspond to the depth and spacing of the teeth or serrations disposed along the serrated blade.
In accordance with another aspect of the present invention, a blade sharpening apparatus for sharpening a serrated blade includes a base structure configured to rest on a support surface and a blade holder coupled with the base structure and configured to securely hold a serrated blade in a position that exposes a toothed or serrated edge of the serrated blade. A threaded rod is rotatably coupled with the base structure about a rotational axis that is offset a fixed distance from a center axis of the threaded rod. A support rod is coupled with the base structure in substantially parallel alignment with the threaded rod and at a spaced distance from the rotational axis of the threaded rod. A grinding wheel is rotationally attached to a shaft and configured to engage teeth or serrations spaced along the toothed or serrated edge of the serrated blade that is secured in the blade holder. The grinding wheel is engaged with the threaded rod and the support rod, and wherein, responsive to rotation of the threaded rod about the rotation axis, the grinding wheel is moved in coinciding oscillating lateral movement and linear longitudinal movement that is configured to move the grinding wheel against the serrated blade to sharpen the toothed or serrated edge of the serrated blade.
In accordance with yet another aspect of the present invention, a method of sharpening a serrated blade includes securing a blade at a blade holder to expose a serrated edge of the blade. A grinding wheel is rotated about a rotational axis. The blade holder or the grinding wheel is laterally oscillated relative to the other at an oscillating distance configured to sharpen a depth between teeth or serrations that are spaced along the serrated edge of the blade. The blade holder or the grinding wheel is moved longitudinally in substantially parallel alignment with the rotational axis of the grinding wheel. The longitudinal and lateral movements coincide to correspond to the depth and spacing of the teeth or serrations along the serrated edge of the blade.
The blade sharpening apparatus and methods of the present invention provide for a coordinated longitudinal and lateral movement between a grinding wheel and a serrated blade such that those longitudinal and lateral movements are configured to coincide in a manner that corresponds to the depth and spacing of the teeth or serrations along the serrated edge of the blade.
These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.
Referring now to the drawings and the illustrative embodiments depicted therein, a blade sharpening apparatus 10 for sharpening a serrated blade 12 (
The blade sharpening apparatus 10 includes a base structure 30 to support the operational devices of the blade sharpening apparatus, such as the grinding wheel 16, oscillating mechanism 22, and linear actuator 24, at the desired positions to properly function together. The base structure may thereby include mounting surfaces, apertures, brackets and the like that are designed to package the operational components of the blade sharpening apparatus 10. The base structure may be integrated into one or more additional structures or may rest on a support surface, such as a counter, table, workbench, or the like. The base structure 30 shown in
The housing 32 may also include a lid or cover 42 that attaches at the rear exterior wall, such as via a hinge, so that the cover 42 is capable of pivoting between an open position (
The grinding wheel 16, as shown in
The grinding wheel 16 is located on or rotatably attached at the base structure 30 in a position for the edge 16a of the wheel 16 to engage the sharpened portion of the teeth spaced along the serrated edge 12a of the blade 12 held by the blade holder 14. The edge 16a of the grinding wheel 16 generally corresponds with the shape of the teeth on the serrated blade 12, such that the grinding wheel 16 may be replaced with a differently shaped grinding wheel to correspond with a differently selected blade that has differently shaped teeth along the serrated edge. Thus, the grinding wheel may have different sized and shaped edges and may also or alternatively be made to have different materials bonded to the periphery of the edge, such as industrial diamonds for diamond wheel and other materials or combinations thereof, such as zirconia, silicon carbide, ceramic, aluminum oxide, or other abrasive compounds.
The blade holder 14 securely holds the serrated blade 12 to expose the serrated edge 12a, such as by clamping along a back portion 12b of the blade 12 (
To move the blade 12 and grinding wheel 16 relative to each other to effectuate the grinding process of the serrated edge 12a, the oscillating mechanism 22 and linear actuator 24 are operated to coincide longitudinal and lateral movements to correspond to the shape of the serrated edge 12a, such as to sharpen along the general depth and spacing of the teeth or serrations. With respect to the oscillating mechanism 22, it may comprise a support member, such as the illustrated threaded rod 26, which is attached at a rotational coupling 28 to position the supported device, such as the blade holder or the grinding wheel, at an offset location from a central axis 28a of the rotational coupling 28 to provide the oscillation movement. As shown in
To assist with maintaining the generally horizontal orientation of the blade 12 during the lateral oscillation, the blade holder 14 extends generally away from the grinding wheel 16 to engage a support rod 54. The support rod 54 is disposed in substantially parallel alignment with and at a spaced distance from the threaded rod 26. To engage the support rod 54, the blade holder 14 includes a pivot block 56 that is disposed at an opposing end of the base plate 48 from the movable part 50 of the clamping device, where the pivot block 56 includes an oval or stadium shaped aperture 56a. As shown in
The linear actuator 24 comprises a threaded rod engaged by the supported device, such as the blade holder or the grinding wheel, whereby the longitudinal movement is induced or provided upon rotation of the threaded rod or by rotation of the support element engaging the threaded rod. As shown in
Each revolution of the threaded rod 26 correlates to lateral movement that corresponds to at least the depth of the teeth along the serrated edge 12a of the blade 12, as the threaded rod 26 is disposed at an offset distance away from the central axis 28a of the rotational coupling 28 that is at least half of the depth of the teeth. The illustrated threaded rod 26 is rotated via a hand crank that is attached at the rotational coupling 28 at an exterior portion of the housing 32, so as to allow the user to adjust the speed at which the threaded rod 26 rotations, and thus the speed at which the blade holder 14 moves laterally and longitudinally relative to the grinding wheel 16. It is also contemplated that the threaded rod 26 may be rotated at the rotational coupling 28 via an electric motor, such as the electric motor used for the grinding wheel that is geared to the desired rotational speed via a set of gears. It is also contemplated that the threaded rod may be replaceable with a different threaded rod have a different thread pattern, such as a different pitch or teeth per inch, which corresponds to how course or fine the teeth on the sharpened blade are cut.
In additional embodiments of the blade sharpening apparatus, it is contemplated that the clamping mechanism and the blade holder may be fixed to the base structure, such that the grinding wheel oscillates laterally and moves longitudinally along the fixed blade. Alternatively, the grinding wheel may configured to be oscillated, such as with an offset rotational axis or other oscillating mechanism, and thus the blade holder may simply be configured to hold the blade fixed or to move the blade only longitudinally along the oscillating grinding wheel. Likewise, it is contemplated that the blade holder may configured to be oscillated, such as with an offset rotational axis or other oscillating mechanism, and thus the grinding wheel may simply be configured to move longitudinally along the oscillating blade holder. Furthermore, it is conceivable that in additional embodiments, the mechanisms necessary to impart the longitudinal and lateral movement may also or alternatively include the use of hydraulic or pneumatic actuators, servo motors, cams, rack and pinion, and gears or the like.
In another exemplary embodiment, a blade sharpening apparatus 510 comprises a motorized grinding wheel assembly 502 and a blade holder 514, as shown in
As illustrated in
As also illustrated in
It will be appreciated that during operation of blade sharpening apparatus 510, the grinding wheel axis 518 and threaded rod 526 each trace a respective oscillating arcuate path while remaining parallel to the grinding path axis 528a. The arc length or amplitude of the arcuate path traced by the grinding wheel axis 518 is determined by the offset distance between the longitudinal axis of the threaded rod 526 and the grinding path axis 528a, according to the offset rotational coupling 528. Thus, the arc length or amplitude of the oscillating arcuate path traced by the grinding wheel 516 can be set according to the choice of rotational coupling 528, and a plurality of different rotational couplings 528 may be provided so that a user may select the appropriate arc length or amplitude of oscillating arcuate path that will be traced by the grinding wheel 516 during operation of the drive motor 521a. Similarly, the pitch of the sinusoidal path can be set according to the pitch of the threads along the threaded rod 526, which may also necessitate a corresponding change of the threaded support member 548a.
Therefore, as illustrated in
The threads of the threaded rod 526 and receiving grooves of the threaded support member 548a are sized with respect to the size of the teeth 12a, 112a of the serrated edge of the tool 12, 112, such that the longitudinal and lateral movements of the motorized grinding wheel assembly 502 are dimensioned according to the size of the teeth 12a, 112 of the serrated edge of the tool 12, 112, respectively. It is also contemplated that the threaded rod may be replaceable with a different threaded rod have a different thread pattern, such as a different pitch or teeth per inch, which corresponds to how course or find the teeth on the sharpened blade are cut.
In operation, the blade sharpening apparatus is prepared for grinding by securing a blade at the blade holder to expose the serrated edge of the blade. The tooth or serration shape of the blade can be examined to determine the appropriate grinding wheel and corresponding lateral and longitudinal movements to follow and sharpen the serrated edge. When the blade sharpening apparatus has been configured for the selected blade, the grinding wheel is rotated about its rotational grinding wheel axis, such as via the electric grinding motor. The blade holder and/or the grinding wheel is then oscillated relative to the other at an oscillating arc length that is configured to sharpen the blade along the depth between teeth spaced along the serrated edge of the selected blade. Also, the blade holder and the grinding wheel are moved longitudinally relative to each other in substantially parallel alignment with the rotational grinding wheel axis. The longitudinal and lateral movements are configured to coincide in a manner that corresponds to the depth and spacing of the teeth along the serrated edge of the blade. When the blade sharpening has been completed, the grinding wheel may stop and the associated housing may be opened, such as via a cover, to remove the blade from the blade holder. Optionally, the housing may include a slide out tray in the sharpening area for collecting debris from sharpening, so as to easily be removed and emptied for cleaning the accumulated debris.
Therefore, exemplary embodiments of the present invention provide for a coordinated longitudinal and lateral movement between a grinding wheel and a serrated blade such that those longitudinal and lateral movements are configured to coincide in a manner that corresponds to the depth (amplitude) and spacing (pitch) of the teeth along the serrated edge of the blade.
Changes and modifications in the specifically-described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law including the doctrine of equivalents.
The application claims the filing benefits of U.S. provisional application Ser. No. 62/546,734, filed Aug. 17, 2017, which is hereby incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
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1444598 | Ferguson | Feb 1923 | A |
1909033 | Yerkey | May 1933 | A |
1961504 | McMillan | Jun 1934 | A |
2041340 | Hartman | May 1936 | A |
2097068 | Johnson | Oct 1937 | A |
2118197 | Hartman | May 1938 | A |
2716845 | Viall, Jr. | Sep 1955 | A |
2769281 | Jones | Nov 1956 | A |
Number | Date | Country |
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101829813 | Nov 2012 | CN |
Number | Date | Country | |
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62546734 | Aug 2017 | US |