US1118181A - Steel die-punch. - Google Patents

Description

A. J. BRADLEY. STEEL DIE PUNCH. APPLICATION FILED APR. 2, 1914.

1,118,181. l PatentedNov.24,1914.

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Z7 d A?? 95 y ANDREW J'. BRADLEY, OF NEW YORK, N. Y.

STEEL DIE-PUNCH.

Specification of Letters Patent.

Patented Nov. 24, 1914.

Application filed April 2, 1914. Serial No. 829,008.

To all fr0/0m t may concern Be it known that I, ANDREW J. BRADLEY, a citizen of the United States, and a resident of the city of New York and State of New York, have invented a new and useful Improvement in Steel Die-Punches, of which the following is a specification.

This invention relates to steel dies and punches such as are used in stencil cutting machines, and comprises the dies described in my pending application Serial No. 778,889, for processes of making steel die punches.

Punches for stencil machines should have bodies with parallel walls exactly conforming to the shape of their faces. A punch body with parallel walls will not stretch the uncut paper surrounding the portions cut out thereby during the punching stroke, as might occur if the punch body was tapered toward the face the punch, and also a parallel walled punch will not catch under the edges of the hole on the return stroke, as might occur if the punch body was upset or enlarged upon its face.

Dies for stencil machines should be a few thousandths of an inch larger than the faces of the punches mating therewith and moreover, the opening through the side should be flared or slightly enlarged toward the bottom of the die in order to provide a clearance for the punched out pieces of the stencil and allow them to fall through readily.

rIhe object of this invention is a steel die and punch having the characteristics hereinafter set forth, and what the invention consists in is more particularly defined in the appended claims.

In the accompanying drawings, in which like characters are used to designate the same parts in the several views,-Figure 1 is a top plan view of the die blank from which both the punch and the die comprised in this invention are made; Fig. 2 is a cross-section of the die blank on the line 2 2 in Fig. l; Fig. 3 is an edge view of the die blank, Fig. 4 is a top plan view of the punch plate prior to assembling the punch pieces with it; Fig. 5 is a cross-section of the punch plate on the line 5--5 inv Fig. 4; Fig. 6 is a cross-section ofthe punch plate and die blank superposed prior to the welding operation. Fig. 7 is a view similar to Fig. 6 showing the punch plate and die blank after the welding operation and prior to separating the punch pieces from the die blank; Fig. 8

is a cross section of the welded punch plate; Fig. 9 is a cross section of the die blank after the punch pieces have been separated therefrom; Fig. l0 is a bottom plan view of the finished punch; Fig. 1l is a top plan view of the finished die; and Fig. l2 is a sidev elevation of the finished punch and die, showing the manner in which they are mounted in a stencil cutting machine. o

In making punches and dies according to this invention it is necessary to have a full set of master punches and dies, comprising all the letters of the alphabet and the usual punctuation marks and characters, together with the numeral figures 2 to 9, inclusive. The master dies are vmade with the character reversed in plan view, and the master punches and dies are very carefully fitted to each other, the clearance between their co'- operating cutting edges being not over onethousandth of an inch. In addition to the letter or number character, the master punches have three pins which cooperate with three holes in. the master dies for punching three dowels or distance posts for positioning the die blank and punch plate at the proper distance apart in the process of making the punch.

The process followed in making the sten cil punches and dies is as follows: A steel die blank 9.1, about three-sixteenths of an inch thick, is placed 'on the master die, and the punch is brought down until it has penetrated about four-fifths through the die blank. This stroke is sufficient to completely sever the punchings 22 from the die blank, but will leave them sticking therein. At the same stroke the three pins in the master punch lining up with the holes in the master die are forced partly through the die blank, but to a. slightly less extent than the punchings,-the lower ends of the pins being set slightly above the face of the punch. The outer' ends of the posts which are raised on the face of the die blank (the top face in Figs. 1 and 2) by the pinsvon the punch block are about one thirty-second of an inch short of the extremities of the punchings 22.

The top edges of thevholes punched in the die blank (the loweredges in Figs. 1 and 9.) are left slightly rounded by the punch instead of having absolutely square corners. lt is impossible to punch soft steel and get absolutely square corners on the top edges of the punch holes due to the'metal surrounding the hole flowing slightly under the pressure brought upon it by the punch. lleretotore, in making stencil dies by master dies having the character cut upright instead ot inverted, it has been necessary to grind oli'1 the top sur ce oli the die blank in order to ,s square corners for the cutting edges ot the stencil die made therefrom. ln this process, the square tace of the die blank becomes the cutting face of the stencil die, and the rminded corners made by the punch are oil' adi'anta in providing bottom clearance in the holes additional to that ma de by the tapered side Walls of the punch. For a similar reason to that causing the top edges oit the holes to be slightly rounded, the projecting edges ot the punchings are slightly rounded. The punchings, howereu hare parallel vfalls exactly conforming in size to the holes in the master die through Which they are forced, instead ot being tapered like the punch. The cutting edges of the holes in the die blank, on the other l'iandn are slightly smaller than the holes in the master die, due to slight contraction after the withdrawal of the punch, and grip "the punchings tightly.

The die blank 21 is laid tace up, as shown in l? (3, and a punch plate 24- is placed on it, Vwith the punched out holes litting the punchings 2z. The punch plate is made with the same master dies With which the die blank was formed, but Without the punch pins, and the punch is forced entirely through the plate. The tapered punch bevels the side Walls ot the holes 25 slightly, the holes being slightly Wider on the side from which the punch approaches. This is the lover side ot the punch plate, as shown inlligs. et and Theclearance between the rounded edges ot the holes in the punch plate and the rounded edges oi the punchings is suiticient to enable the tivo plates to be assembled one on the other as shoivnv 1n Fig'. G, but not sui'hcient to leave any appreci able space between the meeting corners, and accordingly the punch plate serves as a teinplet lor assisting in maintaining the proper alinement of the punchings during the following opera-tion. The posts 23 serve to position the punch plate parallel With the dieblank and insure that the depth to Which the punchings project into the holes in the punch plate shall be uniform.

rlhe punch plate and die-blank are clamped in asseinblec position, and molten steel of the same composition as the punch plate is poured or fused into the cavities in the latter over the punchings This mob ten steel fuses thepunchings to the punch `plate and 'forms a solid punch 26,'as'shown in" 7. The operation vis performed quicky, `and the punch plate and die blank are so massive in proportion to the :molten metal that they are not much'distorted by heat! transferred to them during the operation. loieover, it there is slight distortion ot the punch plate it does not affect the abn-ement oli the punchings, which are securely held by both the punch plate and die- 'blank litter the parts cool, the punch plate and punchings are separated from the dieblank, and the surplus metal 'from the Welding operation is planed or ground off from the back of the punch plate, which then appears as shown in Fig. 8.

l"he die-blank is placed on the master die and lined up by the pins The master punch is forced 'through the die-blank to trim up the cutting edges and give a slight taper or relief to the sides of the holes, and holes 52T are simultaneously punched for the screws Q8 which attach it to the base plate ot the stencil cutting machine. The edges ot the die-blank are trinuned up, the scren7 holes 37 are counter sunk on the top side, and the die-blank is case hardened, forming the finished stencil. die 30, as shown in Figs. ll and l2.

The punch. plate is trimi'ned around its edges and drilled with tiro holes 3l which are counterbored on the side adjacent the punches tor the screws 32 which secure the punch plate to the punch block 83 of the stencil cutting machine. litter mounting the punch plate, the punch is :forced through tue hardened stencil die, which shaves off the edges of the punch Walls to lit the cutting cofres of the die exactly. The punch may be left soft, itt only paper stencils are to .be cut.

lt to be noted that the above described process produces punches and dies having sharp cutting edges exactly conforming to each other Without hand tiling, and Without grinding oit the cutting faces; obviously, the punch portions cooperating With the die 'are exact counterparts oit the holes in the latter' because both are made With the same master dies.

lt is evident that the sizes, shapes and thicknesses ot the seiferal parts, and the materials used, may be changed Without atiiecting the process. lt is also evident that the die-blank may be punched clear through at the lirst stroke ot the dies and the punchings reinserted therein or assembled in a separate templet for holding them properly during the operation ot Welding them to the punch plate. Moreover, the punchings may be secured to the punch plate by Weld ing, brazing, soldering, or any other method which will unite the parts in a secure manner. l

rlhis invention is not limited to the exact num-ber or sequence of operations described as constituting the preferred process of making lmy improved stencil dies. lThe process characterizes the dies forming this inifien'tiojn only in so tar as set forth in the following claims.

What I claim as my invention is:

l. A stencil character punch consisting of a punch plate having portions removed therefrom forming openings conforming to said character, inverted punchings conforming to said character arranged in said open ings and projecting below said punch plate, and means for securing said punchings in said openings.

2. A stencil character punch consisting of a punch plate having portions removed therefrom forming openings conforming to said character, inverted punchings conforming to said character arranged in said openings and projecting below said punch plate, and a filling of fusible metal in said openings securing said punchings therein.

3. A stencil character punch consisting of a metal punch plate having a considerable thickness, and punchings of the same metal and having the saine thickness as said punch plate projecting into said punch plate and fused thereto.

4. A stencil character punch and die comprising straight Walled punch portions and tapering Walled die portions, said portions having their cutting edges composed of counterpart sections of a single piece of metal.

5. A stencil Acharacter punch and die comprising straight Walled punch portions and tapering Walled die portions, said portions having their cutting edges composed of the iaces of counterpart sections of a single piece of flat metal.

6. A stencil character punch and die consisting of a die having punched openings with their side Walls diverging downwardly, a punch comprising a plate which is a replica of said die and punch portions Which are counterparts of said openings projecting from the openings in said plate, said punch portions having straight side Walls, and a filling of fusible metal in the openings in said plate behind said projecting punch portions.

Signed at the city of New York, N. Y., this 28th day of March, 1914:.

` ANDREW J. BRADLEY. Witnesses:

VALTER BENSON, A. MULLALY.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner o! latents,

Washington, I). C.

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