Cutting tool sharpener

Patent metadata

Field	Value
Publication number	US-9849556-B2
Application number	US-201414213264-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Dec 21, 2007
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Method and apparatus for sharpening a cutting tool. In some embodiments, an abrasive endless belt is rotated in tension along a neutral plane between spaced apart first and second rollers. A guide assembly has spaced apart first and second guide surfaces which collectively converge to an intervening base surface to form a guide channel. Upon insertion of a blade of a cutting tool into the guide channel, a selected side of the blade contactingly slides against at least a selected one of the first or second guide surfaces and a first portion of a cutting edge of the blade contactingly engages the base surface to serve as a plunge depth limit stop for the blade. The endless belt is contactingly deflected by a second portion of the cutting edge away from the neutral plane to sharpen the second portion while the first portion remains in contact with the base surface.

First claim

What is claimed is:

1. An apparatus comprising:
an endless belt having an abrasive outer surface and a backing layer inner surface, the endless belt held in tension along a planar extent extending along a neutral plane between spaced apart first and second rollers against which the backing layer inner surface contactingly passes during continuous rotation of the belt along a routing path;
a guide assembly adjacent the planar extent of the belt comprising spaced apart first and second guide surfaces which collectively converge to an intervening base surface to form a guide channel, wherein the first guide surface extends at an acute angle with respect to the second guide surface and the base surface is fixed with respect to the neutral plane, wherein the guide assembly is configured such that during insertion of a blade of a cutting tool into the guide channel, a selected side of the blade contactingly slides against at least a selected one of the first or second guide surfaces and a first portion of a cutting edge of the blade contactingly engages the base surface to serve as a plunge depth limit stop for the blade, and wherein the endless belt is configured to be contactingly deflected by a second portion of the cutting edge away from the neutral plane to sharpen the second portion while the first portion remains in contact with the base surface; and
a tensioner assembly comprising a biasing member that applies a tension force to oppose the deflection of the belt out of the neutral plane, the tensioner assembly continuously applying the tension force in opposition to an insertion force applied to the cutting tool during insertion into the guide assembly, the tension force increasing responsive to deflection of the belt and contact of the first portion of the cutting edge with the base surface.

2. The apparatus of claim 1 , wherein the base surface is a first base surface, the guide channel is a first guide channel adjacent a first edge of the endless belt, the guide assembly further comprises a second base surface of a second guide channel adjacent an opposing second edge of the endless belt, the second base portion configured to serve as a second plunge depth limit stop for the blade, the endless belt configured to pass between the first and second base surfaces, and the second base surface is configured to support a second portion of the cutting edge while the first base surface concurrently supports the first portion of the cutting edge.

3. The apparatus of claim 2 , wherein the planar extent is a first planar extent and the guide assembly is a first guide assembly adjacent the first planar extent, the endless belt comprises a second planar extent extending between a selected one of the first or second rollers and a third roller, and the apparatus further comprises a second guide assembly, nominally identical to the first guide assembly, adjacent the second planar extent.

4. The apparatus of claim 1 , further comprising a proximity switch adjacent the guide assembly configured to sense the presence of the cutting tool within the guide channel.

5. The apparatus of claim 4 , further comprising a motor configured to respectively advance the endless belt in opposing first and second directions, the motor transitioning from the first direction to the second direction responsive to an indication from the proximity switch of the presence of the cutting tool within the guide channel.

6. The apparatus of claim 1 , wherein the first roller is characterized as an idler roller which rotates about a first axis that is fixed relative to the guide assembly, wherein the second roller is characterized as a tensioner roller connected to the tensioner assembly and which rotates about a second axis parallel to the first axis, the tensioner roller moving in a linear direction toward the idler roller responsive to deflection of the endless belt out of plane.

7. The apparatus of claim 1 , wherein the tensioner assembly supplies the tension force to the belt in a range of from about 0.5 pounds to about 10 pounds.

8. The apparatus of claim 1 , wherein the neutral plane is at an angle of about 20 degrees with respect to the first guide surface, wherein upon contact of the first portion of the cutting edge against the base surface the belt is deflected to induce a first, larger angle between the belt and the second portion of the cutting edge adjacent the first guide surface and to induce a second, smaller angle between the belt and the second portion of the cutting edge adjacent the second guide surface.

9. The apparatus of claim 1 , wherein the first roller is characterized as an idler roller which rotates about a first axis that is fixed relative to the guide assembly, wherein the second roller is characterized as a tensioner roller connected to the tensioner assembly and which rotates about a second axis parallel to the first axis and which is moveable toward the guide assembly responsive to deflection of the endless belt, and wherein the tensioner assembly comprises a biasing spring connected to the second roller to impart a deflection force to the second roller to deflect the second axis in a direction away from the first roller parallel to the first guide surface.

10. The apparatus of claim 1 , wherein a distal end of the first guide surface opposite the base surface is arranged in facing relation toward the abrasive outer surface of the endless belt along the planar extent thereof, wherein a distal end of the second guide surface opposite the base surface is arranged in facing relation away from the abrasive outer surface of the endless belt along the planar extent thereof, and wherein the guide assembly is configured such that the selected side of the blade contactingly engages the first guide surface while the cutting edge contactingly engages the base surface.

11. The apparatus of claim 1 , wherein the selected side of the blade is a first side, wherein the blade has an opposing second side, wherein the first and second sides converge to the cutting edge which extends along a length of the blade, and wherein at least one of the first or second sides of the blade are brought into respective contact with the first or second guide surfaces as the first portion of the cutting edge contactingly engages the base surface.

12. The apparatus of claim 11 , wherein the guide assembly is further configured to sequentially support the entirety of the cutting edge as the blade is drawn across the endless belt, wherein the deflection of the belt out of the neutral plane will vary in relation to a profile of the cutting edge.

13. The apparatus of claim 1 , further comprising a housing which supports the first and second rollers, wherein the guide assembly is removably engageable with the housing, and wherein the guide assembly covers at least a selected one of the first or second rollers.

14. The apparatus of claim 1 , further comprising a drive motor configured to rotate a selected one of the first or second rollers via a drive shaft that remains a fixed distance from the guide assembly irrespective of the presentation of the cutting tool therein, wherein a remaining one of the first or second rollers is an idler roller which rotates responsive to rotation of the belt.

15. An apparatus comprising:
an endless belt having an abrasive outer surface and a backing layer inner surface, the endless belt held in tension along a planar extent extending along a neutral plane between spaced apart first and second rollers against which the backing layer inner surface contactingly passes during continuous rotation of the belt along a routing path;
a tensioner assembly attached

Assignees

• Darex Llc

Inventors

• Dovel Daniel T

Classifications

• B24B3/54

  of hand or table knives · CPC title

• B24B3/52

  of shear blades or scissors · CPC title

• B24B21/20

  for controlling or adjusting the tracking or the tension of the grinding belt · CPC title

• B24B3/36 Primary

  of cutting blades (B24B3/58 takes precedence) · CPC title