Tool sharpener with concave sharpening surface

Patent metadata

Field	Value
Publication number	US-12447573-B2
Application number	US-202117544525-A
Country	US
Kind code	B2
Filing date	Dec 7, 2021
Priority date	May 17, 2019
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

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 sharpening operation in which a user retracts the blade along a longitudinal drawing axis through the sharpening stage. A pair of intersecting sharpening elements may be provided to form a substantially v-shaped groove for a ripper-type sharpening stage. The sharpening element(s) may be fixed or tiltable with respect to the housing. The sharpening element(s) may further be moveable in a lateral direction to narrow or widen the v-shaped groove and change the convex geometry and edge angle imparted to the blade.

First claim

What is claimed is:

1. A sharpener for sharpening a cutting tool having a blade, the sharpener comprising:
a housing; and
a sharpening stage comprising a sharpening element characterized as a plate and having a rear facing surface and a relief surface, the rear facing surface and the relief surface meet to form a first curvilinearly extending, concave sharpening contact region configured to impart a corresponding convex sharpening geometry to a selected side of the blade during a sharpening operation in which a user retracts the blade along a longitudinal drawing axis through the sharpening stage, the relief surface and the longitudinal drawing axis forming an acute relief angle.

2. The sharpener of claim 1 , wherein the sharpening element is a first sharpening element, and the sharpening stage further comprises a second sharpening element having 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 curvilinearly extending, concave sharpening contact region and the second curvilinearly extending, concave sharpening contact region to impart the corresponding convex sharpening geometry to the blade.

3. The sharpener of claim 1 , wherein the sharpening element is immovably fixed to the housing so that the sharpening stage is characterized as a stationary sharpening stage.

4. The sharpener of claim 3 , wherein the sharpening element extends at a nonorthogonal angle with respect to the longitudinal drawing axis.

5. The sharpener of claim 1 , wherein the sharpening element is rotatable with respect to the housing so that the sharpening stage is characterized as a tiltable sharpening stage.

6. The sharpener of claim 1 , wherein the plate has respective length, width and thickness dimensions, the thickness dimension extending in a direction that lies along a plane along which the longitudinal drawing axis extends, the thickness dimension is 25% or less than either the length or width dimension.

7. The sharpener of claim 1 , wherein the sharpening element is formed of at least a selected one of carbide, steel, diamond or ceramic.

8. The sharpener of claim 1 , further comprising an attachment mechanism configured to releasably secure the sharpening element to the housing to allow the user to remove and reinstall the sharpening element as required.

9. The sharpener of claim 1 , further comprising an adjustment mechanism that imparts movement of the sharpening element in a lateral direction orthogonal to the longitudinal drawing axis.

10. The sharpener of claim 1 , wherein the sharpening element has a front facing surface, wherein the front and rear facing surfaces are nominally parallel, and wherein the relief surface extends between the front and rear facing surfaces at a nonorthogonal angle thereto.

11. The sharpener of claim 1 , wherein the acute relief angle is established by tilting the sharpening element relative to the drawing axis.

12. The sharpener of claim 1 , wherein the acute relief angle is established by the relief surface being formed at an acute angle relative to the rear facing surface.

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.

14. The sharpener of claim 13 , wherein the sharpening stage is characterized as a stationary sharpening stage so that the first and second sharpening elements are maintained in a fixed, non-moving relation with respect to the housing.

15. The sharpener of claim 13 , wherein the sharpening stage is characterized as a tiltable sharpening stage so that the first and second sharpening elements are rotatable with respect to the housing about a transverse rotational axis nominally orthogonal to the longitudinal drawing axis.

16. The sharpener of claim 13 , wherein the first and second sharpening elements are each characterized as a plate having respective width, length and thickness dimensions, the thickness dimension being smaller than each of the respective width and length dimensions.

17. The sharpener of claim 16 , wherein the thickness dimension is 25% or less of the smaller of the respective length or width dimension.

18. The sharpener of claim 13 , wherein each of the first and second sharpening elements is formed of at least a selected one of carbide, steel, diamond or ceramic.

19. The sharpener of claim 13 , wherein the first sharpening element is moveable with respect to the second sharpening element in a lateral direction to selectively increase or decrease an overall intervening distance between the first and second curvilinearly extending, concave sharpening contact regions to thereby widen or narrow the substantially v-shaped groove.

20. The sharpener of claim 13 , wherein the first and second sharpening elements are secured to the housing at a non-orthogonal orientation with respect to the longitudinal drawing axis.

21. The sharpener of claim 13 , wherein the first and second sharpening elements are secured to the housing so as to be in an orthogonal orientation with respect to the longitudinal drawing axis, and wherein the respective first and second relief surfaces are specially configured to extend in a non-orthogonal relation to opposing front and rear facing surfaces of the first and second sharpening elements.

22. The sharpener of claim 13 , wherein the acute relief angle is established by tilting the first and second sharpening elements relative to the drawing axis.

23. The sharpener of claim 13 , wherein the acute relief angles are established by the relief surfaces being formed at acute angles relative to the associated rear facing surfaces.

Assignees

• Darex Llc

Inventors

• Zachariasen Joseph T
• Campbell Travis

Classifications

• B24B3/54 Primary

  of hand or table knives · CPC title