Any shading and cross-hatching are not features of the design but are utilized to illustrate the surface contours of the knife sharpener in the drawings.
The ornamental design for a knife sharpener, as shown and described.
Filed: Apr 29, 2009
Date of Patent: Aug 31, 2010
Inventors: Brett A. Friesen (Detroit Lakes, MN), Mitchel T. LeBrasseur (Ludlow, MA), Ken Moncrief (Richmond, VA)
Primary Examiner: Philip S Hyder
Assistant Examiner: Roselynne Cody
Attorney: Neustel Law Offices
Application Number: 29/336,197