Granted Patent B2

US 7,686,676 · App. 12/103,007 · Granted Mar 30, 2010

Abstract

Claims (25)

1. A knife sharpener capable of precision sharpening of hunting and similar knives that have a first and second blade face, each of which terminates at a facet that meets the corresponding facet to create the knife edge where at least the first of the blade faces has a lower distinct planar or concave section adjacent the edge facet, the lower planer or concave section of the face being set at an angle to the center line of the blade thickness that is different from the angle of an adjoining upper section of the same blade face located adjacent to the back of the blade, said sharpener comprising a sharpening member having a sharpening surface, a knife guide having a planar angle knife guide surface designed for intimate sliding and sustaining contact with the second face of the blade in order to position an edge facet on the first of the faces into precise angular relation with said sharpening surface, and a knife holding spring having at least one arm that applies force predominantly against the first face of the blade at one or more locations on the lower planar or concave section of the first face that is adjacent to the edge facet being sharpened in order that only the lower section adjacent the edge on the second face of said blade is dominantly pressured to align with and remain in intimate sliding alignment with said guide surface of knife guide as the blade edge facet on the first face is being sharpened, said knife holding spring arm having an elbow to apply a dominant holding force, a support portion above said elbow, a free end below said elbow, and said free end being a withdrawing shape that can contact the lower blade face.

2. A knife sharpener according to claim 1 wherein said sharpening surface of said sharpening member is an abrasive coated surface.

3. A knife sharpener according to claim 1 wherein said spring is generally in the shape of an inverted U having a bight portion which merges into downwardly extending arms, each of said arms having an elbow portion, the spacing between said elbow portions being greater than the width of said bight, and each of said arms terminating in an outer free end with said outer free ends converging toward each other when said outer free ends are mounted in their knife holding position.

4. A method of precision sharpening of hunting and similar knives that have a first and second blade face, each of which terminate at a facet that meets the corresponding facet to create a knife edge where at least the first of the blade faces has a distinct planar or concave section adjacent the edge facet, and the lower planar or concave section of the face being set at an angle to the center of the blade thickness that is different from the angle of an adjoining upper section of the same blade face located adjacent to the back of the blade comprising the steps of placing the blade in a sharpener against a sharpening member having a sharpening surface and against a knife guiding surface of a planar angle knife guide, and holding the blade against the knife guide by use of a knife holding spring which applies force against the first face of the blade predominantly at one or more locations on the lower planar or concave section of the first face that is adjacent to the edge facet being sharpened in order that the lower section adjacent the edge of the second face of the blade is pressured to align with and remain in intimate sliding alignment with the guide surface of the knife guide as the blade edge facet on the first face is being sharpened.

5. The method of claim 4 including applying insufficient force by the spring against the upper section of the blade to cause the upper section of the second side of the knife to align with the knife guide surface.

6. The method of claim 4 including applying a force by the spring against the upper section of the blade that is less than that which would cause misalignment of the lower section on the second side of the blade with the knife guide surface.

7. The method of claim 4 wherein the spring applies a holding force to one face of the blade that is less than ⅝ inch in height and that has two planar faces each of which terminates at a facet that meets with the adjacent facet to create the knife edge, and the force applied by the spring being of a magnitude adequate to hold the opposing face of the blade in intimate sliding contact with the guide surface of the knife guide.

8. The method of claim 4 wherein the blade is sharpened by abrasive action from an abrasive coated surface of the sharpening member.

9. An electric knife sharpener capable of precision sharpening of hunting and similar knives that have a first and second blade face, each of which terminates at a facet that meets the corresponding facet to create the knife edge where at least the first of the blade faces has a lower distinct planar or concave section adjacent the edge facet, the lower planer or concave section of the face being set at an angle to the center line of the blade thickness that is different from the angle of an adjoining upper section of the same blade face located adjacent to the back of the blade, said sharpener comprising a rotatable sharpening member having a sharpening surface, a knife guide having a planar angle knife guide surface designed for intimate sliding and sustaining contact with the second face of the blade in order to position an edge facet on the first of the faces into precise angular relation with said sharpening surface, a knife holding spring having at least one arm that applies force against the first face of the blade predominantly at one or more locations on the lower planar or concave section of the first face that is adjacent to the edge facet being sharpened in order that the lower section adjacent the edge on the second face of said blade is pressured to align with and remain in intimate sliding alignment with said guide surface of knife guide as the blade edge facet on the first face is being sharpened, said knife holding spring arm having an intermediary located elbow, an upper portion above said elbow, and a free end below said elbow.

10. A sharpener according to claim 9 wherein said rotatable sharpening member is slidably mounted on a shaft, a sharpening member spring urging said sharpening member to slide on said shaft, and said sharpening member spring acting in concert with said knife holding spring to insure that the lower blade section is held in good contact with said guide surface while the blade edge facet is in contact with said sharpening member and the lower section of the blade face is in contact with said spring arm.

11. A sharpener according to claim 9 wherein said free end of said spring arm has a reduced cross-section as compared to the cross-section of said upper portion of said spring arm.

12. A sharpener according to claim 9 wherein said elbow is located a distance of from ⅝ to ¾ inch above the tip of said free end and a distance of from ⅝ to ¾ inch below the upper end of said upper portion.

13. A sharpener according to claim 9 wherein said free end of said spring arm is in contact with said guide surface when no blade is present.

14. A sharpener according to claim 9 wherein said free end of said spring arm is completely spaced from and diverges away from said guide surface when no blade is present.

15. A sharpener according to claim 9 wherein said knife holding spring is an inverted U having two of said arms, and said free ends of said arms diverging away from each other.

16. A sharpener according to claim 9 wherein said knife holding spring is an inverted U having two of said arms, and said free ends of said arms converging toward each other at their tips.

17. A sharpener according to claim 9 wherein said knife sharpener has multiple stages, each of said stages having a power driven rotatable sharpening member, said knife holding spring being an inverted U having two of said arms, said knife holding spring being mounted between two of said stages, and each of said spring arms being located in a respective one of said stages.

18. A sharpener according to claim 1 wherein said free end of said spring arm has a reduced cross-section as compared to the cross-section of said upper portion of said spring arm.

19. A sharpener according to claim 1 wherein said elbow is located a distance of from ⅝ to ¾ inch above the tip of said free end and a distance of from ⅝ to ¾ inch below the upper end of said upper portion.

20. A sharpener according to claim 1 wherein said free end of said spring arm is in contact with said guide surface when no blade is present.

21. A sharpener according to claim 1 wherein said free end of said spring arm is completely spaced from and diverges away from said guide surface when no blade is present.

22. A sharpener according to claim 1 wherein said knife holding spring is an inverted U having two of said arms, and said free ends of said arms diverging away from each other.

23. A sharpener according to claim 1 wherein said knife holding spring is an inverted U having two of said arms, and said free ends of said arms converging toward each other at their tips.

24. A sharpener according to claim 1 wherein said spring arm has only a single bend.

25. A sharpener according to claim 1 wherein said free end of said spring arm is straight from said bend to its tip.

Assignments (13)