Cutting tool sharpener

Patent metadata

Field	Value
Publication number	US-9956662-B2
Application number	US-201715708275-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Dec 21, 2007
Publication date	May 1, 2018
Grant date	May 1, 2018

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 for sharpening a cutting tool having an elongated cutting edge, the apparatus comprising:
a plurality of spaced apart rollers comprising at least first, second and third rollers rotatable about parallel first, second and third axes, respectively, wherein the first, second and third rollers are placed in a substantially triangular arrangement so that a distance between the first and second axes is substantially equal to a distance between the first and third axes and greater than a distance between the second and third axes;
a flexible abrasive belt having a selected linear stiffness and routed along the plurality of spaced apart rollers to define a belt path having a first extent that extends along a first plane tangential to the first and second rollers and a second extent that extends along a second plane tangential to the first and third rollers, each of the first and second planes symmetric with respect to a centerline passing through a central axis about which the first roller rotates, the central axis bisecting an overall angle between the first and second planes;
a tensioner assembly connected to at least one of the plurality of spaced apart rollers and adapted to exert a bias force thereon to translate the corresponding axis of the at least one of the plurality of spaced apart rollers with respect to the axes of the remaining rollers to maintain a tension along the flexible abrasive belt and resist bending of the flexible abrasive belt out of at least one of the first or second planes;
an electric motor adapted to drive the flexible abrasive belt in at least a first selected rotational direction along the belt path; and
a sharpening guide assembly secured adjacent the flexible abrasive belt comprising a first guide slot adjacent the first extent of the flexible abrasive belt along the first plane and a second guide slot adjacent the second extent of the flexible abrasive belt along the second plane, wherein the first and second guide slots further comprise first and second cutting edge guide surfaces adapted to contactingly engage the cutting edge of the cutting tool during presentation of the respective first and second sides of the cutting tool against first and second cutting edge guide surfaces, the first and second cutting edge guide surfaces being symmetric about the centerline, the first guide slot configured to contactingly support a cutting tool in a selected orientation during presentation of a first side of the cutting tool against the first extent of the flexible abrasive belt, the second guide slot configured to contactingly support the cutting tool in said selected orientation during presentation of an opposing second side of the cutting tool against the second extent of the flexible abrasive belt, wherein the first and second extents of the flexible abrasive belt respectively deform at a radius of curvature responsive to said presentation of the respective first and second sides of the cutting tool thereagainst.

2. The apparatus of claim I, wherein the second and third rollers are characterized as guide rollers each having an annular outer surface which contactingly engages an inner surface of the flexible abrasive belt and inner and outer annular flanges at opposing ends of the annular outer surface configured to retain the flexible abrasive belt adjacent the annular outer surface.

3. The apparatus of claim 1 , wherein at least one of the first, second or third rollers is characterized as a crowned roller.

4. The apparatus of claim 1 , wherein the first guide slot further comprises a first side guide surface configured to support a side of the cutting tool during presentation of the cutting edge against the first extent wherein the second guide slot further comprises a second side guide surface configured to support a side of the cutting tool during presentation of the cutting edge against the second extent, wherein the first side guide surface extends at a selected angle with respect to the first extent, and wherein the second side guide surface extends at the selected angle with respect to the second extent.

5. The apparatus of claim 1 , wherein the electric motor is further configured to advance the flexible abrasive belt in an opposing second rotational direction along the belt path.

6. The apparatus of claim 1 , wherein the first roller has a first outermost diameter, and wherein each of the second and third rollers have a second outermost diameter greater than the first outermost diameter.

7. The apparatus of claim 1 , wherein the tensioner assembly comprises a spring which exerts a bias force upon the at least one of the plurality of rollers.

8. The apparatus of claim 1 , further comprising a base unit which supports the plurality of rollers and a guide housing removably attachable to the base unit, the base unit incorporating the sharpening guide assembly.

9. The apparatus of claim 8 , wherein the base unit comprises a base housing in which the electric motor is disposed, the base housing configured to be supported on a base surface and having a user engageable switch to activate the electric motor and initiate movement of the flexible abrasive belt along the belt path.

10. An apparatus for sharpening a cutting tool having opposing first and second side surfaces and a cutting edge therebetween, the apparatus comprising:
a plurality of spaced apart rollers;
a flexible abrasive belt having an abrasive top surface and an opposing backing surface, the flexible abrasive belt routed around the plurality of rollers to form a belt path defining respective first and second planar extents tangential to and on opposing sides of a first roller of the plurality of rollers, the first planar extent extending from the first roller to a second roller and the second planar extent extending from the first roller to a third roller, each of the first and second planar extents symmetric with and non-parallel to a centerline passing through a central axis about which the first roller rotates, the central axis bisecting an overall angle between the first and second planar extents, the plurality of spaced apart rollers comprising a belt tracking mechanism to nominally maintain the flexible abrasive belt positioned over the plurality of rollers;
a motor adapted to drive the flexible abrasive belt in at least a first selected direction along the belt path; and
a sharpening guide assembly secured adjacent the flexible abrasive belt and the first roller comprising a first guide slot adjacent the first planar extent of the flexible abrasive belt and a second guide slot adjacent the second planar extent of the flexible abrasive belt, wherein the first and second guide slots comprise first and second cutting edge guide surfaces adapted to contactingly engage the cutting edge of the cutting tool during presentation of the respective first and second sides of the cutting tool against first and second side guide surfaces, the first and second side guide surfaces symmetric about the centerline of the first roller so that each of the first and second side guide surfaces are disposed at a common acute angle with respect to the first and second planar extents of the flexible abrasive belt to support the opposing first and second side surfaces of the cutting tool as the cutting edge of the cutting tool is contactingly presented against the respective first and second planar extents.

11. The apparatus of claim 10 , wherein the belt tracking mechanism comprises opposing first and second belt tracking flanges extending from at least a selected one of the first, second or third rollers on opposing sides of the flexible abrasive belt.

12. The apparatus of claim 10 , w

Assignees

• Darex Llc

Inventors

• Dovel Daniel T

Classifications

• 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

• B24B3/52

  of shear blades or scissors · CPC title

• B24B3/54

  of hand or table knives · CPC title