US2481309A - Sharpening tool - Google Patents

Description

Sept" 6, 11949. E. GUNNARSON 24r81173@9 SHARPENING TOOL Filed Feb. 15, 1947 2 SheetsSheet l jLIIIH A x I l5 7 FIG. 7.

ZNVENTOR.

ELoF GUNNARSON ATTORNEY Sept. 6, 1949. E. GUNNARSON SHARPENING TOOL Filed Feb. 15, 1947 2 Sheets-Sheet 2 FIG. 2.

FIG. IO.

INVENTOR. ELOF GUNNARSQN ATTORNEY Patented Sept. 6, 1949 SHARPENING TOOL Elof Gunnarson, Minneapolis, Minn.

Application February 15, 1947, Serial No. 728,756

2 Claims.

My invention relates to a sharpening tool designed to provide a means for drawing a strip of sharpening material, such as emery cloth, paper, or other similar abrasive material stretched taut over the various surfaces of the tool. The tool includes an adjustable means for regulating the tension on the strip of abrasive material and to insure the holding of the same over the various surfaces in a firm and set position.

A feature of my tool resides in providing the body of the tool formed of light weight metal or other suitable material with multiplicity of surfaces. The body of the tool is formed with a long forward end which extends virtually into a point where two of the long surfaces join together. At the rear of the long surfaces formed on the body of the tool, I provide short parallelly extending surfaces which are fiat and which connect into a bifurcated end which leads into a recess in which a spring gripper operates to draw the free ends of the abrasive material taut and thereby tightening the strip of abrasive material which extends over all of the outer surface of the tool. The spring gripper is formed with a pair of serrated edges which bite into the free ends of the abrasive material to grip the same. The spring gripper is secured to a screw member which extends freely into an opening for receiving the same in the inner rib of the tool.

- I provide a starlike member which is threaded to the shank of the gripper and which operates within a recess in the center rib of the tool to engage the threaded shank of the gripper and operate the same to draw the gripper into the recess formed in the rear end of the tool, closing the jaws of the gripper by engagement with the sides of the recess and causing-the teeth of the gripper to firmly engage the free ends of the abrasive strip to draw it tight and thus hold the abrasive strip firmly in place over the surfaces of the tool. When the gripping jaws are released by operating the starlike member, the jaws of the same expand to permit insertion of the free ends of the abrasive material.

A feature of my tool resides in providing one of the long surfaces with a longitudinal curve from one end to the other and with the outer surface thereof arcuated outwardly in transverse cross section to form a compound curved surface wherein one curve extends longitudinally of the surface and the other curve extends transversely thereof.

It is also a feature to provide a long straight fiat surface on the body of the tool opposite the arcuated surface just described. The two longest surfaces on my tool extend virtually into a point which permits the tool to be used in close cutting. or into recesses or within small spaces Where the point of the tool will extend.

The rear fiat surfaces which extend parallel are;

comparatively short as they form the rear end of the abrasive tool. Furthermore, the rear bifurcated end of the tool forms two small pointed ends which may be used insome places where it is desired touse an abrasive surface.

The multiplicity of surfaces of my tool over which the abrasive strip is stretched provide an abrasive tool which is very desirable for various uses. Thus I provide a tool which may be used. in the shop, in the home, or wherever an abrasive surface is desired and Where it is desirable to sharpen knives or other tools and where a tool.

of the abrasive strip and singularly riveting each.

folded-over end to provide a shoulder on each end; of the abrasive strip. Then when the abrasive strip is passed around the supports andthe free ends are engaged by the clamping hooks, thepull will be exerted against the shoulders and thus the abrasive strip can be drawn taut around the supporting member. The ends of the abrasive strip may be folded over to form shoulders and then the two folded-over ends riveted together to form an endless abrasive strip.

The purpose of reinforcin the ends or attach: ing the same together as just described is to in sure a firm gripping end for the clamp to engage against so as to insure drawing the abrasive strip around the frame of the suporting member as tight as possible.

These features together with other details and objects will be more fully hereinafter set forth. In the drawings forming part of this specifica tion:

Figure 1 is a side view of my sharpening tool. Figure 2 is .a top view of the tool. Figure 3 is a front view of my sharpening tool. Figure 4 is a rear view of the Sharpening tool. Figure 5 is an enlarged side view of the rear end of my tool. Figure 6 is a cross section on the line 6-6 of Figure 5.

These shoulders:

Figure 7 is a cross section on the line 1-4 of Figure 5.

Figure 8 is a perspective of the gripper member with its threaded shank.

Figure 9 is a perspective of one end of the abrasive strip showing the free end folded over and riveted to provide a gripping shoulder on the inner surface threof.

Figure 10 is a detail of the ends of the abrasive strip which are folded over and riveted together to form an endless abrasive strip.

My sharpening tool A is formed with a body portion I having an I-beam cross section to provide a central reinforcing rib II.

The member I 0 is formed with a multiplicity of angularly disposed surfaces I2, l3, 14, I5, I6, and I1, over which a strip B of abrasive material is adapted to be stretched taut. In this manner the abrasive material is adapted to fit closely against the respective surfaces I2 to I! inclusive, and thus the abrasive material is firmly held in place in a manner to cover all of the outer surfaces of the body member Ill. I

The surfaces l2 and I1 converge into virtually a point l8, around which the abrasive strip B extends.

' The under surface I! is convex while the surface I2 is flat.

The surfaces I3 and I6 are approximately parallel to each other, while the surfaces Ill and I5 provide a rear bifurcated end to the sharpening tool A. V Y

The reinforcing rib II is cut away at I!) to decrease the weight of the tool A and to provide a hand hole so that the tool may be freely gripped by the fingers of the operators hand in the use of the tool. The rib II extending between the surfaces l3 and I6 is enlarged to provide a hole for the threaded shank of the gripping member C. A transverse recess 2| is provided in the rib II which is adapted to receive a star-shaped thumb nut 22 which is threaded to the shank 26.

The inner ends of the surfaces l4 and I5 which provide the bifurcated end of the tool A converge into a recess 23, the sides of which are virtually parallel. The gripping member C is formed with a threaded shank 20 and the spring gripping jaws 24, which are formed with serrated gripping edges in hook formation. Normally the gripping jaws 24 are expanded beyond the width of the opening 23 and are adapted to engage the ends of the abrasive member or strip B as illustrated in Figure 5.

As the star thumb nut 22 is rotated to draw the gripping member C inward, the jaws 24 are forced against the cam surfaces l4 and I5.

The abrasive strip B is practically the same width as the surfaces I2 to I! inclusive,'so that it will cover these surfaces when drawn taut over the same. The strip B may be plain on its ends or the ends may be reinforced by doubling under a portion 26 and securing the same with a rivet or staple 21. In this manner I provide a gripping shoulder 28 across the front ends of the strip which may be engaged by the gripping hooks 25 to assist in drawing the abrasive strip B taut over the surfaces of the tool A.

The abrasive strip B may be folded over at the ends to provide the shoulders 29 and the foldedover ends secured together by the rivet or staple 30 thus connecting the strip B into an endless loop which may be extended over the surfaces I2 to i! inclusive and the shoulders 29 engaged by the hook ends 25 so that the nut 22 may draw the abrasive strip taut over the surfaces of the tool A.

My tool A is designed to provide an abrasive tool wherein the abrasive surface may be readily changed at any time and a new abrasive strip attached to the tool. This tool A may be used as a knife sharpening device or may be used for a multiplicity of purposes. The surface I! is convex transversely and longitudinally to provide a compound curve to the surface.

The pointed end of the tool A permits the same to be used in close places which is also true of the bifurcated end at the rear of the tool. The hand hole [9 forms an opening for the fingers of the operator so that the tool A may be gripped from either side. The tool A may also be engaged with the operators hand extending around the outside of the surfaces.

When the abrasive strip is attached to the tool A the gripping jaws 24 are released into the position illustrated in Figure 5 by operating the thumb nut 22. Then by reversing the operation of the nut 22 the spring gripping jaws 24 may be drawn into the position illustrated in Figure 1 and the dotted position of Figure 5 so as to draw the ends of the abrasive strip taut over the surfaces of the strip. This operation is reversed to remove the abrasive strip from the tool A.

While the tool A may be shown of a specific form and with various angularly disposed surfaces, it is apparent that the design may be changed within the scope of the appending claims without departing from the purpose or intention of the invention.

I claim:

1. A sharpening tool including a body portion having a hand hole formed through said body portion to permit free gripping of the same, outer ,angularly disposed surfaces formed on said body having parallel longitudinal sides, a strip of abrasive material approximately the same width as said surfaces, means for gripping said abrasive material to draw the same taut over said surfaces, said means including a clamp, threaded screw and a nut for opening and closing said screw and clamp, and cam surfaces adjacent said clamp to progressively restrict the jaws of said clamp to close and bite into said abrasive material as the same is drawn taut over said outer surfaces of said body.

2. A sharpening tool comprising a body formed of a single piece of lightweight material, a multiplicity of outer surfaces formed on said body, a spring gripping means, screw and nut means for operating said spring gripping means, cam surfaces against which said spring gripping means operates to force the jaws of said gripping means together, and a strip of abrasive material having shoulders formed therein against which said spring gripping means are adapted to engage when said gripping means are caused to grip said abrasive to draw it taut over said surfaces of said tool thereby providing a multiplicity of abrasive surfaces which may be replaced when worn out.

ELOF GUNNARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,736,869 Albertson et al Nov. 26, 1929 2,063,338 Pritchard et a1 Dec. 8, 1936 2,401,116 Stang May 23, 1946 2,415,367 Pavlovic Feb. 4, 1947

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