US 12,447,573 B2
Tool sharpener with concave sharpening surface
Joseph T. Zachariasen, Medford, OR (US); and Travis Campbell, Medford, OR (US)
Assigned to Darex, LLC, Ashland, OR (US)
Filed by Darex, LLC, Ashland, OR (US)
Filed on Dec. 7, 2021, as Appl. No. 17/544,525.
Application 17/544,525 is a continuation in part of application No. 15/929,718, filed on May 18, 2020, granted, now 11,192,217, issued on Dec. 7, 2021.
Claims priority of provisional application 62/849,464, filed on May 17, 2019.
Prior Publication US 2022/0088737 A1, Mar. 24, 2022
Int. Cl. B24B 3/54 (2006.01)
CPC B24B 3/54 (2013.01) 23 Claims
OG exemplary drawing
 
13. A sharpener for sharpening a cutting tool having a blade, the sharpener comprising:
a housing; and
a sharpening stage adapted to facilitate a sharpening operation upon the cutting tool responsive to retraction, by a user, of the blade along a longitudinal drawing axis, the sharpening stage comprising a first sharpening element having a first rear facing surface and a first relief surface, the first rear facing surface and the first relief surface meet to form a first curvilinearly extending, concave sharpening contact region, and a second sharpening element having a second rear facing surface and a second relief surface, the second rear facing surface and the second relief surface meet to form a second curvilinearly extending, concave sharpening contact region, the second sharpening element intersecting the first sharpening element to form a substantially v-shaped groove between the first and second curvilinearly extending, concave sharpening contact regions to impart a corresponding convex sharpening geometry to the blade during the sharpening operation in which the user retracts the blade along the longitudinal drawing axis through the sharpening stage, each of the relief surfaces and the longitudinal drawing axis forming an acute relief angle.