Abrading – Abrading process – Razor – knife – or scissors sharpening
Reexamination Certificate
1999-09-07
2001-07-10
Banks, Derris H. (Department: 3723)
Abrading
Abrading process
Razor, knife, or scissors sharpening
C405S182000, C405S302000
Reexamination Certificate
active
06257962
ABSTRACT:
TECHNICAL FIELD
The present invention relates to apparatus and methods for forming hollow-ground surfaces simultaneously on opposite sides of a knife blade blank.
BACKGROUND
Knife blade edges are conventionally sharpened by passing the edge of the blade between a pair of grinding wheels. The grinding wheels typically remove metal from the knife blade edge and form tapered surfaces along opposite side edges of the blade to form a sharpened knife blade edge. Knife blade edges are typically sharpened by applying the blade edge to grinding surfaces having various grits, typically from coarse to fine, such that a fine sharp knife blade edge can be formed.
A finished hollow-ground knife blade, however, is characterized by a concave surface on each of the opposite side faces of the knife blade and spaced back from the sharpened edge of the blade. Typically, these hollow-ground side faces are individually manually ground. Thus, hollow-ground knife blades often have non-symmetrical opposite hollow-ground side faces. While care and skill will sometimes result in a near-symmetrical hollow-ground knife blade, each side face of the blade requires substantial individual attention and time which increases the cost of hollow-ground knives. Accordingly, there is a need for a machine for accurately, quickly and simultaneously forming hollow-ground knife blades.
DISCLOSURE OF THE INVENTION
In accordance with a preferred embodiment of the present invention, there is provided a belt grinder in which two grinding belts are employed, enabling opposite side surfaces of a knife to be simultaneously ground thereby forming a hollow-ground knife blade from a knife blank. Particularly, an electric motor drives primary and secondary shafts. Grinding wheels are mounted on the respective shafts and define a gap or nip therebetween. A grinding belt is deployed about each of the grinding wheels and an idler pulley offset to one side of the grinding wheel. The idler pulleys are preferably adjustable toward and away from the associated grinding pulley to adjust the tension of the belts about the grinding pulleys. Also, each idler pulley is angularly adjustable relative to the associated grinding wheel to enable adjustment of the run of the grinding belt to keep it straight and true on the grinding wheel and prevent the belt from riding up over the margins of the grinding wheel and idler pulley.
In a preferred embodiment of the invention, the gap between the grinding wheels is adjustable to accommodate knife blanks of different thicknesses. For example, and in this preferred embodiment, the bearings for one of the shafts and the shaft itself are mounted on a slidable plate. Thus, the bearings, shaft and grinding wheel mounted on the shaft are movable toward and away from the opposing bearings, shaft and grinding wheel into infinitely adjusted positions within that range. By displacing the plate into an adjusted position, the gap between the grinding belts may be adjusted.
In the operation of the foregoing-described machine, a knife blank is disposed in the gap between the grinding wheels. It will be appreciated that the grinding wheels rotate in opposite directions and in an upward direction from the gap. By disposing the knife blank in the gap between the wheels and sliding the blank forwardly and rearwardly, a hollow-ground surface is provided simultaneously on the opposite sides of the knife blank. That is, the simultaneous grinding of the opposite side faces of the knife blank forms the concave side surfaces in the knife blank characteristic of a hollow-ground knife blade and in a manner which is substantially symmetrical about the length of the knife. Also, the hollow-ground faces are spaced or set back from the edge of the knife, which edge, of course, is sharpened after formation of the hollow-ground side faces.
In a preferred embodiment according to the present invention, there is provided a method of forming a hollow-ground knife blade comprising the steps of (a) inserting a knife blade blank into a gap between a pair of rotating grinding wheels and (b) forming concave surfaces simultaneously along opposite side faces of the blank spaced back from an edge of the blank nearest the gap by grinding opposite side faces of the knife blade blank.
In a further preferred embodiment according to the present invention, there is provided apparatus for forming a hollow-ground knife comprising a pair of grinding wheels defining a gap therebetween, a motor for driving the wheels, a pair of idler pulleys, a first endless grinding belt disposed about a first idler pulley of the pair thereof and a first wheel of the pair of grinding wheels, a second endless grinding belt disposed about a idler pulley of the second pair of idler pulleys and a second wheel of the pair of grinding wheels, the first wheel being mounted for movement toward and away from the second wheel to adjust the gap between the wheels and an adjustable element mounting each idler pulley for angular adjustment of the idler pulleys relative to the grinding wheels to adjust the angular relationship of planes passing through the idler pulleys and the grinding wheels.
In a still further preferred embodiment according to the present invention, there is provided apparatus for forming a hollow-ground knife blade comprising a pair of grinding wheels defining a gap therebetween, a motor for driving the wheels, a pair of idler pulleys, a first endless grinding belt disposed about a first idler pulley of the pair thereof and a first wheel of the pair of grinding wheels, a second endless grinding belt disposed about a second idler pulley of the pair of idler pulleys and a second wheel of the pair of grinding wheels, a slide carrying the first grinding wheel and the first idler pulley for movement toward and away from the second wheel and the second idler pulley to adjust the gap between the wheels and a lock for locking the slide in an adjusted position thereby maintaining the gap between the grinding wheels in an adjusted position.
REFERENCES:
patent: 3543446 (1970-12-01), Kilian
patent: 4617763 (1986-10-01), Edling
patent: 4671018 (1987-06-01), Ekhoff
patent: 4676029 (1987-06-01), Palmer
patent: 5012618 (1991-05-01), Price et al.
patent: 5099615 (1992-03-01), Ruble et al.
patent: 5651722 (1997-07-01), Werner
patent: 5888123 (1999-03-01), Wang
Cissell Steven N
Franke Norman T.
Banks Derris H.
Nixon & Vanderhye
Ojini Anthony
LandOfFree
Apparatus and methods for forming hollow-ground knife blades does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and methods for forming hollow-ground knife blades, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and methods for forming hollow-ground knife blades will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2519725