ALEXANDRIA, Va., Oct. 28 -- United States Patent no. 12,447,573, issued on Oct. 21, was assigned to Darex LLC (Ashland, Ore.).
"Tool sharpener with concave sharpening surface" was invented by Joseph T. Zachariasen (Medford, Ore.) and Travis Campbell (Medford, Ore.).
According to the abstract* released by the U.S. Patent & Trademark Office: "Apparatus configured to sharpen a blade of a cutting tool. In some embodiments, a sharpener is provided having a housing and a sharpening stage with at least one sharpening element. Each sharpening element is characterized as a plate and has a curvilinearly extending, concave sharpening surface configured to impart a corresponding convex sharpening geometry to a selected side of the blade during a shar...