Automatic knife sharpening machine with sharpness detection

Patent metadata

Field	Value
Publication number	US-11850698-B2
Application number	US-202016775551-A
Country	US
Kind code	B2
Filing date	Jan 29, 2020
Priority date	Jan 31, 2019
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

An automatic knife sharpening machine may include a vice to grip a blade of a knife and a pair of grind wheels to grind material from the blade. The machine may include a scanner to determine a profile of an edge of the blade, and a sharpness sensor to determine a sharpness level of the edge. The machine may include a controller. The controller may perform a first sharpening pass on the knife by moving the grind wheels into contact with the blade, and advancing the grind wheels longitudinally along the blade from adjacent the vice towards a tip of the blade with the grind wheels in contact with the blade. The controller may determine, using the sharpness sensor, the sharpness level of the edge after the first sharpening pass and perform at least one second sharpening pass when the determined sharpness level is less than a threshold sharpness level.

First claim

What is claimed is:

1. An automatic knife sharpening machine, comprising:
a vice configured to grip a blade of a knife;
a pair of grind wheels configured to grind material from the blade;
a scanner configured to determine a profile of an edge of the blade;
a sharpness sensor configured to determine a sharpness level of the edge; and
a controller configured to:
perform a first sharpening pass on the knife by:
vertically moving the grind wheels into contact with the blade at a position adjacent the vice; and
advancing the grind wheels longitudinally along the blade from the position adjacent the vice towards a tip of the blade with the grind wheels in contact with the blade;

determine, using the sharpness sensor, the sharpness level of the edge after the first sharpening pass; and
when the determined sharpness level is less than a threshold sharpness level, adjust a grind parameter based on the determined sharpness level and perform at least one second sharpening pass on the knife.

2. The automatic knife sharpening machine of claim 1 , wherein the grind wheels are disposed in a movable grind head.

3. The automatic knife sharpening machine of claim 1 , wherein the controller is further configured to pitch the grind wheels relative to the vice such that an axis of the grind wheels is within ten degrees of parallel to local tangents along the profile during the first and the second sharpening passes.

4. The automatic knife sharpening machine of claim 1 , wherein the sharpness sensor includes:
a light source configured to direct light on the edge of the blade; and
a receiver configured to detect the light reflected by the edge.

5. The automatic knife sharpening machine of claim 4 , wherein the controller is configured to determine the sharpness level of the edge based on at least one of an intensity, a power level, or a wavelength of the reflected light.

6. The automatic knife sharpening machine of claim 1 , further including a profile sensor configured to determine a thickness of the blade.

7. The automatic knife sharpening machine of claim 6 , wherein the controller is further configured to adjust a distance between the grind wheels based on the determined thickness.

8. The automatic knife sharpening machine of claim 1 , wherein the scanner determines the profile of the edge of the blade by means of an optical sensor.

9. The automatic knife sharpening machine of claim 8 , wherein the optical sensor is a camera.

10. The automatic knife sharpening machine of claim 1 , further including a vacuum system fluidly coupled to the volume of air surrounding the locations where grinding occurs.

11. The automatic knife sharpening machine of claim 1 , wherein the scanner and the sharpness sensor are disposed in a movable sensor head.

12. A method of automatically sharpening a knife, comprising:
clamping a blade of the knife in a vice;
scanning the blade using a scanner;
determining, using a controller, an initial blade profile based on signals received from the scanner;
performing a first sharpening pass on the knife by:
vertically engaging a pair of grind wheels disposed on either side of the blade with the blade at a position adjacent the vice; and
advancing the grind wheels along a longitudinal direction of the blade from the position adjacent the vice to adjacent a tip of the blade with the grind wheels in contact with the blade;

determining, using a sharpness sensor, a sharpness level of an edge of the blade after performing the first sharpening pass; and
when the determined sharpness level is less than a threshold sharpness level, adjusting a grind parameter based on the determined sharpness level, and performing at least one second sharpening pass on the knife.

13. The method of claim 12 , further including:
determining using a profile sensor a thickness of the blade; and
adjusting a distance between the grind wheels based on the determined thickness.

14. The method of claim 13 , further including:
determining an initial sharpness level of the edge before performing the first sharpening pass;
selecting grind parameters based on at least one of the initial sharpness level, the initial blade profile, or the thickness of the blade; and
performing the first sharpening pass based on the selected grind parameters.

15. The method of claim 14 , wherein the grind parameters include at least one of a type of abrasive of the grind wheels, a rotational speed of the grind wheels, a rate of advance of the grind wheels along the longitudinal direction of the blade, or a pitch angle of the grind wheels.

16. The method of claim 14 , further including using a machine learning model to select the grind parameters.

17. The method of claim 12 , wherein determining the sharpness level includes:
directing a light from a light source on the edge of the blade;
detecting, using a receiver, the light reflected by the edge; and
determining the sharpness level based on at least one of an intensity, a power level, or a wavelength of the reflected light.

18. The method of claim 12 , wherein the sharpness level is a first sharpness level, and the method further includes:
determining a second sharpness level of the edge after performing the at least one second sharpening pass; and
halting sharpening operations when the second sharpness level is greater than the threshold sharpness level.

19. The method of claim 12 , wherein the scanner and the sharpness sensor are disposed in a movable sensor head.

20. The method of claim 12 , wherein the grind wheels are disposed in a movable grind head.

Assignees

• Hillman Group Inc

Inventors

• Fowler Whitfield Janes
• Stone Sean
• Bennett Ari
• Kastenbaum Jeffrey
• Lyons David Frederick
• Kolchin Dmitriy

Classifications

• B24B3/54 Primary

  of hand or table knives · CPC title

• B24B49/12

  involving optical means · CPC title