Blade sharpener

Abstract

Two thin cylindrical sharpening rods are made of a ceramic material which is loaded with a strong abrasive, and are set in an elongated hand held base in adjacent angular relationship to each other and in acute angular relation to the base member. That relationship is such that each rod will perform a proper sharpening action on a blade when that blade is held in perpendicular relationship to the longitudinal axis of the base and is moved down against the sharpening rod and along the length of the blade from the handle to the tip. The diameter of the sharpening rod is small enough so that it will make a point contact with the entire cutting edge of the blade as it is moved downward and from handle to tip, even when the blade has a serrated edge. The rods are supported in the base so that they can be rotated to present fresh surfaces to the blade edge thus allowing the entire outer surface of the sharpening rod to be available for use. The rods can be removed from the base for convenient storage and so that ordinary kitchen cleanser can be used to remove the metal deposits from the rods.

Description

BACKGROUND OF THE INVENTION

The top edges of cylindrical crocks have been traditionally used for sharpening knives and other blades virtually throughout the history of America. As such crocks have disappeared from ordinary usage in many households, this source of a sharpening "stone" for knives has gradually disappeared. Because the ceramic crock was not made primarily for sharpening purposes but rather for use as a cooking, holding, serving and eating utensil, it was not made to withstand repeated sharpenings and tended to show some signs of wear in time.

Sharpeners utilizing crossed abrasive pads, rods or the like have long been used, but typically, the knife was drawn between two such sharpening pads or stones or rods so that both sides of the knife were sharpened simultaneously. This had the obvious and serious drawback that the blade contacted the sharpening medium only at an infinitesimally small portion of that medium. Consequently, these sharpeners tend to wear out at a very rapid rate at the point where the knife blades come in contact with the sharpener.

In common use are hand held sharpeners in which washer-like discs are rotatably mounted on a first pin and are interspaced by similar washer-like discs rotatably mounted on a second pin. A knife blade is pulled between and in contact with the edges of the washers adjacent each other at the top thereof. These sharpeners are "powerful" in that they do actually scrape a considerable amount of metal off of the blade in the process of sharpening. This metal tends to cling to the sharpener itself and to the sharpened blade, and thus constitutes a safety and a health hazard. Also, the angle afforded by the intersection of these two sets of washer-like discs forms a very abrupt sharpened edge which is subject to rapid dulling.

In sharpening serrated cutting blades, these intersecting disc sharpeners suffer from the severe disadvantage that only the top edge of serrated blades is "attacked" by the washer-like discs, so that repeated use of such a sharpener has the tendency to literally remove the serrated edge rather than to continually resharpen it.

BRIEF SUMMARY OF THE INVENTION

Sharpening rods of the invention are of a uniform cylindrical dimension throughout, and are constituted of abrasive material, for example, a ceramic material into which is dispersed an abrasive substance such as aluminum oxide has been found to work well. These rods are supported in cylindrical openings provided in a base in such a manner that the top or the bottom of the pair of rods is in immediately adjacent relationship to the same portion of the other rod and so that each rod extends upwardly therefrom. In a typical installation the base can be constituted as a half-round piece of wood in which the flat side is designed to be held against a flat horizontal surface, and the rods extend upwardly and angularly outwardly therefrom.

With the base held in horizontal position by the opposite hand, for example, a knife holding hand is used to position the blade of the knife in perpendicular relationship to the longitudinal axis of the base and to draw the knife down against one or the other of the sharpening rods, at the same time moving the blade longitudinally to move the point of contact of the blade with the rod progressively from the handle toward the tip of the blade.

When this sharpening stroke has been completed, it is repeated by bringing the knife down against the other rod, thus completing a sharpening action on the other side of the blade.

A serrated edge of a knife can be sharpened fully by constituting the diameter of the rods as less than the "tooth" spacing of serrations along the knife edge.

IN THE DRAWINGS

FIG. 1 is a perspective view of a first form of blade sharpener of the invention showing the positioning of a knife blade as it would be held while it was being sharpened against one of the sharpening rods;

FIG. 2 is a front elevational view of the sharpener of FIG. 1 and showing in cross section the positioning of a blade to be sharpened against each of the ceramic rods of the invention;

FIG. 3 is an enlarged fragmentary and elevational view of the sharpener and one of the blades of FIG. 2 as seen on the line 3--3 in that figure;

FIG. 4 is an enlarged vertical sectional view taken on the line 4--4 in FIG. 3; and

FIG. 5 is a front elevational view of a modified form of a blade sharpener.

DESCRIPTION OF PREFERRED EMBODIMENTS

The blade sharpener 10 of the first form of the invention includes an elongated horizontal base 12 of wood or other suitable material and cylindrical rods 14 and 16 mounted therein in spaced relation to each other at the base and to come into overlapping adjacent relation to each other at the tip of each.

The base 12 has a horizontal bottom surface designed to firmly support the sharpener on a table or the like, as seen in FIG. 2. The base is long enough to provide a hold-down portion to the left of the rods as seen in FIG. 2 and to the right of the rods as seen in FIG. 5, this hold-down portion being sufficiently long to allow a hand to hold the base down in contact with the table top without endangering the hand during the sharpening operation. Mounting is accomplished by inserting the rods 14 and 16 into provided holes 18 and 20, respectively, in the base 12. The fit of the rods in the holes will be snug, but will be such that the rods can easily be rotated and can easily be removed as for cleaning and storage.

In use, a knife such as shown at 22 and having a blade 24 is situated so that its blade is in perpendicular relation to the longitudinal axis of the base 12 and its cutting edge 28 is initially in contact with an upper portion of one of the rods, for example, the rod 14 at a position in adjacent relationship to a handle 26 of the knife and as suggested in dotted lines in FIG. 1.

Maintaining this perpendicular relationship with respect to the base, the blade is "cut" down into the sharpening rod and the knife is moved longitudinally at the same time so that the point of contact moves down the rod 14 and from adjacent the blade to adjacent the tip of the knife.

This action is repeated with the other side of the knife blade 24 being initially put into contact with the left side of the rod 16, as seen in FIG. 1, and the longitudinal movement of the knife blade again accompanies the downward cutting action of the blade against rod 16.

This action is repeated on the left and right side of the knife blade until the blade is sharpened.

The relationship of the knife blade to the sharpening rod 14 is most clearly seen in FIG. 4 and in FIG. 3. From these figures it is evident that the actual sharpening takes place at a point of contact between the knife blade and the sharpening rod, and it can be seen from these figures that as the knife blade is moved longitudinally and downwardly, that point of contact will move smoothly along cutting edge 28 of the blade 24 and along each of the serrations in that edge.

In that modified form of the invention as seen in FIG. 5, rods 34 and 36 are mounted in a base 32 in much the same manner as in connection with the first form of the invention, except that the lower ends of the rods are situated in adjacent relationship to each other and the upper ends of the rods are spaced apart.

In this form of the invention, the action in sharpening a knife blade or any other appropriate blade, such as that of scissors, for example, is exactly the same as in the first form of the invention except that the interior surfaces of the rods (those facing the other rod) will be used rather than the exterior surfaces thereof.

This form of the invention has the advantage that it will tend to keep the moving knife blade confined and will lessen the opportunity for damage due to careless handling whereby the sharpened and sharpening blade could slash into something nearby. It has the disadvantage, however, that careless handling could allow the knife blade to go clear down to the base where it could encounter the opposite and facing sharpening rod to the detriment of the cutting edge.

Claims

The embodiments of the invention in which an exclusive property or priviledge is claimed are defined as follows:

1. A blade sharpener including a base, a pair of relatively thin but elongated sharpening rods mounted in the base to extend upwardly from the base in acute angular relationship to said base, said rods lying in substantially the same plane, and the acute angle between each rod and the base being the same as that of the other rod and the base, each rod leaning in an opposite direction from the base, wherein said rods are mounted in said base in spaced relation to each other and wherein upper portions of said rods terminate in adjacent relation to each other.