US2586823A

US2586823A - Hand die

Info

Publication number: US2586823A
Application number: US693026A
Authority: US
Inventors: Paul J Huhn
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1946-08-26
Filing date: 1946-08-26
Publication date: 1952-02-26
Anticipated expiration: 1969-02-26

Description

Feb. 26, 1952 HUHN 2,586,823

HAND DIE Filed Aug. 26, 1946 lz @9955 j 'Patented Feb. 26, 1952 HAND DIE Paul J. Huhn, St. Paul, Minn., assignor to Minnesota Mining & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Application August 26, 1946, Serial No. 693,026

3 Claims.

The present invention relates to hand dies for cutting out swatches or patches or sections of sheet material of predetermined size and shape.

Heretofore the necessary periodic sharpening of such dies has altered the contour of the cutting edge sufficiently to render the die unfit for further use after a number of sharpenings. In cutting work where accurate size is critical, dies had to be discarded after. one or two or only a few sharpenings.

An example of the latter may be seen in the sheet abrasive (sandpaper) art where hand dies are used to cut out test samples of the freshly coated Web at regular intervals during the con tinuous making process. To determine whether the coating weight of the sample in terms of grains per unit area is correct, the simplest and quickest method is to weigh a sample just as it is cut from the web and then compare it to the standard. This method, however, requires that the sample that is cut out by the die be of a very precise size, exactly the same as the standard. This requires an accurate die. The cutting of sandpaper dulls the die edge rapidly. The life of the old style hand dies in abrasive sampling work is thus very short.

An objective of the present invention is to provide a die capable of being maintained at a high standard of sharpness and precision for a long period of time at low cost;

Broadly, the present invention provides a die having a body portion, a handle, a form extending downwardly from the body whose outline is w the same as that of the section of'material to be cut out, a removable cutting blade and means for holding the blade pressed against the outer.

side of the form in conformity to the contour thereof. l

' The invention is exemplified by a device described hereinafter and illustrated in the accompanying drawings in which:

Figure 1 is a side elevation with one corner of the die broken away;

Figure 2 is a plan view; Figure 3 is a bottom elevation; Figures 4, 5 and 6 show examples of alternative shapes for the form;

Figure 7 shows a modification of the bladeholding means; and

Figure 8 shows a junction of blades at a corner. The body portion comprises a. base In, a handle-supporting frame II and a vertical handle I! having a rounded striking surface I3 on its top. a

A form [4 extends downwardly from the body whose outline I5 formed by its outer sides and edges is that of the section of sheet material to be cut by the die when in use. In the illustrated device the form [4 is rectangular. It may be of other shape, such as arcuate, as indicated in Figure 4, circular (Figure 5), rectangular with rounded corners (Figure 6), etc.

Adjacent the edges or sides of the form are blades l6--l6 and lll'|. The blades are edgeground rather than center-ground so that their cutting edges :0 are in the plane of their side surfaces rather than in their longitudinal center, as more clearly appears in Figures 7 and 8. Thus (referring to Figure 8), when the edged sides of the blades face inwardly against the sides of the form l4, and the ends of the blades |6l6 are made to fit close up against the inside sides of the blades I1-I1, and the blades l'l-ll extend in length beyond the intersection of the blades, the edges :1: of the four blades meet at y at each of the four corners of the form l4 and extend all around it, thus forming a continuous cutting edge rectangular in outline, coinciding exactly with that of the said form l4.

Means for holding the blades pressed closely against the sides [5 of the form [4 so as to conform them to its contour of outline, are provided in the form of ridges I8 which project downwardly from the body and surround the form in spaced relation thereto, and setscrews l9 in the said ridges positioned to bear or press against the blades I6-|6 and [1-H which latter are in the slots or spaces 20 that occur between the form I4 and the ridges I8. In Figures 1, 2 and 8, the slots 2|] are shown as being of approximately the same width as the thickness of the blades. Alternatively they may be wider, as shown in Figure 7, so as to accommodate relatively rigid or inflexible bearing plates 2| between the blades and the ridges I8. The setscrews It then bear against the plates 2| which latter bear against the blades evenly throughout the area of the latter, thereby providing a high degree of conformity of the blades to the form. If desired, the ridges l8 need not be continuous but may be provided only at the points where the setscrews occur.- Means other than setscrews may be associated with the ridge [8 to serve as pressing members for holding a blade against the form to conform it thereto, such for example as wedges inserted between a blade and the ridge IS. The plate 2|, for example (Figure 7), may be shaped to serve as a wedge, to be driven upwardly into the slot 20 between the blade I6 and the ridge E8, in whichcase the illustrated setscrews would not be needed.

Dies made in accordance with this invention are of various sizes according to the work being done. The over-all dimensions of the illustrated die are 4%" x 61-2" x 7%,", and it cuts out a section of sheet material measuring 4 x 6".

In operation, the sheet material to be cut is laid temporarily upon a suitable anvil member such as a wooden block. The die is then placed on the top surface of the sheet with its cutting edges a: resting thereon, whereupon the top l3 of the die handle I2 is struck with a mallet or hammer, thereby cutting out a section of the-- sheet which exactly coincides with the form I i in size and shape. The cutout section may then be removed from the die by pressing downwardly upon it with the fingers through the opening 22 in the form 14.

Since the edges l of the form 14 never contact the work, they are not subject to dulling as were the corresponding edges of the hand dies heretofore known. In the latter the cutting edges were at the same time the edges of the form which determined the size and shape of the section to be cut; sharpening the edges would therefore alter the shape of the form, thereby rendering the die unsuitable for further precision cutting, and eventually unsuitable for any cutting at all.

The present die, on the other hand, may be used for many years without any defacement or alteration of the contour of the form. When dull, the die may be restored to its original degree of sharpness and accuracy simply by removing its blades for sharpening or for replacement with new blades. Meanwhile'the size and shape of the section of sheet material that the die will cut out never changes because the sides and,edges l5 which determine what the said size and shape shall be, are never defaced or altered in any way. The die thus has an almost unlimited life, during the full course of which it retains the full degree of its original efficiency. The expense of frequent replacement of entire new dies may therefore now be substantially eliminated.

The present die also overcomes much of the distortion caused by thermal changes. In the old hand dies, a slight thermal change that was sufficient to effect the thin edge portion of the die without effecting the body portion would warp the cutting edge. In the present die, however, the separate blades may expand and contract in their slots independently of the relatively stationary body portion without serious distortion.

The dies of this invention may be used for cutting any kind of sheet material that is severable by the downward pressure of a knife, such as paper, cloth, cellophane, plastic sheets, adhesive tape or sheeting, etc. Due to their novel capacity for maintenance of sharpness and accuracy to the full degree at low cost for an almost unlimited period of time, the dies are particularly useful for cutting out test samples during continuous making processes of coated sheets that tend to dull the cutting edges rapidly, such as sandpaper, glass bead coated sheets such as the reflex reflector sheets sold under the trade-mark Scotchlite, and the like. Such work requires that the variance in size of the cut-out samples does not exceed .0003 to .0004 inch. The dies are also useful in cutting out sections of thin sheet metal.

I claim:

1. A hand die of the character described for.

cutting out test samples of abrasive sheet ma- I V terial during the making process of the latter comprising a body portion having a flat undersurface, a handle extending upwardly from the top of the body, the said undersurface having two parallel spaced apart slots extending lengthwise of the body and two parallel spaced apart slots extending crosswise of the body and intersecting the first two slots at an angle of thereby forming a fixed rectangular form surrounded by four fixed ridges spaced therefrom, an individual removable edge-ground straight cutting blade in each slot projecting downwardly from the undersurface of the body with the edged sides of the blades facing inwardly against the form and meeting at the intersections to form a continuous rectangular cutting edge, and set screws extending through each of the four ridges to the slots with the ends of the screws bearing against the blades to hold the latter pressed against the form.

2; A hand die for cutting out test samples of abrasive sheet material during the making process of the latter comprising a body portion having a flat undersurface, a handle extending upwardly from the top of the body, the said undersurface having two parallel spaced apart slots extending lengthwise of the body and two parallel spaced apart slots extending crosswise of the body and intersecting the first two slots at an angle of 90, thereby forming a rectangular form surrounded by four ridges spaced therefrom, an individual removable edge-ground straight cutting blade in each slot projecting downwardly from the undersurface of the body with the edged sides of the blades facing inwardly against the form and meeting at the intersections to form a continuous rectangular cutting edge, a bearing plate in each slot adjacent the outer surface of each blade, and setscrews extending through each of the four ridges to the slots with the ends of the screws bearing against the plates to hold the blades pressed against the form.

3. A hand die of the character described for cutting out test samples of abrasive sheet material during the making process of the latter comprising a body portion having a fiat undersurface, a handle extending upwardly from the top of the body, the said undersurface having two parallel spaced apart slots extending lengthwise of the body and two parallel spaced apart slots extending crosswise of the body and intersecting the first two slots at an angle of 90, thereby forming a fixed rectangular form surrounded by four fixed ridges spaced therefrom, an individual removable edge-ground straight cutting blade in each slot projecting downwardly from the undersurface of the body with the edged sides of the blades facing inwardly against the form and meeting at the intersections to form a continuous rectangular cutting edge, and means for holding the blades pressed against the sides of the form.

PAUL J. HUHN.

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

UNITED STATES PATENTS Number Name Date 74,095 Hunt Feb. 4,v 1868 198,219 Schell Dec. 18, 1877 594,186 Walter Nov. 2 8, 1897 1,630,988 Tyler May 31, 1927