US2795975A - Rotary knife blade steel - Google Patents

Description

June 18, 1957 L. D. STONER ROTARY KNIFE BLADE STEEL Filed Jan. 25, 1957 INVENTOR. ZEWAs'RASTaNER BY Jinn/i ROTARY KNIFE BLADE STEEL Lewis D. Stoner, San Francisco, Calif.

Application January 25, 1957, Serial No. 636,288

4 Claims. (Cl. 76-892) My present invention relates to cutlery and more particularly to a new and novel cutting blade sharpening device and it has for an object the provision of a simple and convenient means for maintaining the cutting edge of a knife blade in a sharpened condition without a grinding or abrading action.

Another object of the invention is to provide a simple and handy device by which the cutting edge of a knife blade may be restored to its original degree of sharpness with a swaging or burnishing operation comparable to that obtained by the use of a butchers steel.

Another object of the invention is to provide a new and novel device for restoring the dull edge of a cutting implement without the use of an abrasive or other means in which the edge of a knife is sharpened by the removal of metal therefrom.

A further object of the invention is to provide a device for maintaining the cutting edge of a knife blade in a keenly sharpened condition by a swaging or rolling operation that will result in a work hardening of the metal at the cutting edge of the blade.

It is well known that the use of a steel as employed by butchers forms a keen cutting edge upon a knife blade without any grinding away of the blade metal. Resort has long been had to steeling in order to provide a keen edge and prolong the life of a knife without frequent grinding which would naturally shorten its useful life. The steeling of a knife blade as performed by professional butchers requires considerable practice and is a hazardous operation when first attempted by a novice. It is, therefore, a further object of my invention to provide a knife blade sharpening device by which the cutting edge of a knife may be restored to its original degree of sharpness by a swaging or burnishing operation without danger of being cut as might happen in the use of a conventional butchers steel.

Other objects and advantages will be in part evident to those skilled in the art and in part pointed out in connection with the accompanying drawing, wherein there is shown by way of illustration and not of limitation a preferred embodiment of the invention.

In the drawing wherein like numerals refer to like parts throughout the several views:

Figure 1 is a perspective view of a device constructed in accordance with my invention,

Figure 2 is a top view of the device as shown in Figure 1, and

Figure 3 is an enlarged view of the blade sharpening element of my device.

As is well known the cutting edge of a knife blade progressively looses its keen edge in use and while it is conceivable that carving knife blades might be formed of steel which would retain a keen edge for a much longer period, the use of such steel results in a blade which as a whole will be brittle and subject to breaking upon a flexing thereof as is often encountered in the use. It is, therefore, the practice to form these blades of a relatively Patent C Patented June 18, 1957 softer steel which will maintain a cutting edge for an acceptable period of time before a grinding and/ or stoning is necessary. In the meantime, between these grinding and/or stoning operations, the keenness of the cutting edge can be maintained by stropping or by steeling as with a butchers steel. The stropping of a carving knife is diflicult, if not impossible and, therefore, up to the present time there only remains for this purpose a butchers steel.

The use of a butchers steel has the advantage over grinding in that it does not grind away metal and results in a swaging or burnishing action that produces a hardening at the cutting edge of the knife blade which can be maintained for a considerable time between grindings. It is this desirable result which is contemplated and obtained by my invention. In fact, it has been found that a keen edge may be maintained upon carving knives indefinitely without regrinding where the blade is protected and not subjected to knicking due to accident or misuse such as would of itself require a regrinding.

For a description of my invention, reference is now had to the accompanying drawing where in Figure 1, I have shown a device embodying the principles of my invention as comprising a supporting body 10 of metal, hard wood or a plastic. This supporting body 10 may take any desired shape. It is here shown as of a size and shape that can be conveniently gripped between the thumb and index finger of a hand in the manner shown and firmly held against the horizontal top of a table or bench while a knife blade, shown by dot and dash lines and designated by the numeral 11, is drawn backward and forward at one end thereof. To prevent a sliding of the supporting body 10 upon the table top or bench, I have also shown a strip of anti-slipping material 12 which may be of rubber or the like as secured along the bottom thereof.

Extending outwardly from the end of the supporting block 10, there is a swaging roller 13, which as shown in Figure 2 of the drawing, is mounted upon a shaft or spindle 14 that is driven into the supporting body 10 with a tight fit and at an angle in a horizontal plane with respect to the end of the supporting body 10. In this arrangement, the shaft or spindle 14 has a portion of enlarged diameter 15 about which the roller 13 turns and at the outer end thereof there is a retaining head 16 that will secure the roller 13 against displacement when the shaft 14 is driven tightly into the supporting body 10 as above stated. Because of this angular disposition of the shaft or spindle 14, it will be noted that the supporting body 10 is counterbored about the axis of the spindle, as at 17. When assembled the face or end of the supporting body 10 will extend horizontally at an angle with respect to the axis about which the roller 13 rotates and vertically in a plane extending substantially centrally through the roller 13. In order to compensate for an average knife blade and thus dispose the cutting edge thereof substantially centrally between the inclined sides of the V-groove in the roller 13, I have shown the end face of the supporting body 10 as being slightly chamfered as at 18 in that portion thereof which functions as a guide for the movements of the knife blade 11 as it passes over the roller 13 when in use.

As is more clearly brought out in Figure 3 of the drawing, the roller 13 is provided with a V-like annular groove having inclined and oppositely disposed sides 19 which may be straight or curved as shown and with a spacing and depth of the groove such that the cutting edge of a knife will engage the opposed sides 19 of the V-groove in the roller 13 substantially equi-distant at opposite sides of its vertical center. In this operation, the blade is held out of contact with the bottom of the groove therein ice when the knife blade is passed thereover at such angle, as is here indicated bythe fragmentary showing of a knife blade 20 as positioned thereupon.

In the use of my device the blade is held between .the sides of the V-groove on the periphery of-the roller 13. At such an angle with the axis of the roller 13 the blade 29 cannot contact the bottom of the groove but will contact the groove only at its sides. At these contact points the two sides at the edge of the blade will contact the adjacent sides of the V-groove. As these contact points comprise only linear radii of the roller 13 the two cones forming its V-groove, and the corresponding linear outline of the blade itself will form contacting surfaces which are miscroscopically small. Therefore, with very small amounts of pressure applied to the blade in forcing the two sides of its blade against the corresponding sides of the V-groove, these minute contact areas result in a very great unit area pressure between the blade and the sides of the V-groove.

The pressure thus applied While a blade is given a reciprocating movement forward and backward within the V-groove will cause the roller 13 to rotate. Therefore, the conical surfaces of the V-groove may be said to swage and burnish the metal of the blade upon both of its sides so that at the apex of an edge, flattened or rounded by its use as a cutting implement, will be restored to its true edge and made to cut keenly again.

It will be readily understood that this method of restoring keenness to dulled edges can be used upon knives or blades of any form, straight, curved or circular. Its further advantage is that it operates with equal success upon cutlery metals of all kinds, varieties and grades, because it is not essential that these metals have a fine cutlery grain when this method is used in sharpening them. From softest iron to hardest alloy steels it makes them all equally keen by compressing molecules of metal to a keen edge form.

While I have, for the sake of clearness and in order to disclose my invention so that the same can be readily understood, described and illustrated a specific form and arrangement, I desire to have it understood that this invention is not limited to the specific form disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and all such changes as come Within the scope of the appended claims are to be considered as part of this invention.

Having thus described my invention, What I claim and desire to secure by Letters Patent is:

1. A cutting blade sharpening device, comprising a body member having a substantially vertical blade guiding surface when held upon a supporting horizontal surface, and a rotary burnishing element mounted upon said body member for rotation about an axis disposed at an angle in the horizontal plane and extending through the plane of said blade guiding surface, said rotary burnishing element having an annular groove with inclined sides between which the cutting edge of a knife blade is positioned as the knife blade is moved backward and forward in contact with the blade guiding surface of said body member to cause rotation of said burnishing element.

2. A cutting blade sharpening device, comprising a hardened metallic roller having a V-like annular groove extending therearound with inclined sides of parabolic curvature flaring outwardly from the bottom of said groove, a shaft disposed at an angle in a horizontal plane upon which said roller is rotatably mounted, and a support for said shaft having a knife blade guiding surface extending in a plane bisecting the V-like annular groove of said roller at an angle, whereby in being moved along said blade guiding surface with a reciprocating movement and in contact with the inclined sides of said groove as said roller rotates about said shaft the cutting edge of the blade will be swaged and hardened with a burnishing action.

3. A household blade sharpening device, comprising a body member having a substantially vertical blade guiding surface at one end when held upon a horizontal supporting surface, a shaft carried by said body members extending at an angle in a horizontal plane and through the plane of said blade guiding surface, a roller mounted upon said shaft having an annular V-shaped groove with inclined sides between which the cutting edge of a knife blade is supported and held out of contact with the bottom of said V-shaped groove as the knife blade is moved backward and forward along the blade guiding surface of said body member.

4. A household blade sharpening device, comprising a hardened metallic roller having a V-groove extending therearound with sides flaring outwardly from the bottom of said groove, a shaft upon which said roller is rotatably mounted, and a support for said shaft having a knife blade guiding surface extending in a vertical plane at an angle to the axis of said roller, whereby in being moved along the blade guiding surface of said support with a recirocating movement the cutting edge of a knife blade will be held in contact with the sides of said groove and subjected to a swaging action as said roller rotates about said supporting shaft.

No references cited.

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