US499820A - George p - Google Patents

Description

UNiTED e STATES Erice@ i GEORGE F. CHAMPNEY, DF TAUNTON, MASSACHUSETTS, ASSIGNOR OF THREE-FIFTHS TO ALFRED-H. HARRISON, OF LONDON, ENGLAND.

ART oF MAKING ollas.`

SPECIFICATION forming' part 0f Letters Patent No. 499,820, dated June 20, 1893.

Application tiled December Il, 1889. Serial No. 332.533. (No model.)

To all whom it muy concern:

',Be it known that I, GEORGE F. CHAMPNEY, a citizen of the UnitedStates, residing at Taunton,county of Bristol, and State of Mas- .to the value of the process. stacle referred to` is the liability of the patrice the making and also by cutting .from a solid steel block al patriceI in relief, which is then pressed byslow degrees and repeated blows into the-die block. Both methods are very tedious and costly and neither produces perfect work, since the traces of the tools are necessarily present. It has also been proposed to attach the patrice to a drop hammer, place the block 4of steel While-hot under it, and force the patrice into the block by dropping the hammer. The last mentioned process has had the advantage of. much greater speed and economy than those before mentioned, but is 4open to t`wo considerable objections. The `first of these is that where the work is delicate vand difficult the die is likely'to'. be imperfect.

Thus, for instance, when figures portrayed' are sharp, particularly about the outer edge of its face, the angles are likely to'be imper-4 fectly reproduced in the die block and the` distinctness ofthe original thus lost. As lineA work abounds in parts thusdifticult of reproduction this obstacle has been a seriousone The second obwhen made from cast iron or other fragile or soft metal, to be broken or crushed by'the force of the blow and thus fail to effectthe. desired impression.

My present inventionis in the nature'or` an improvement upon the last mentioned process and is based upon the discovery thatthe obstacles juststated can be avoided and theI process perfected by giving to the patrice-at .the moment 4ot ts'impact upon the dieblock.

an exceptionally high degree of speed. This" A vhigh Yvelocity secures." a' result which, in the perfection and certainty of the 'die produced, is new and which cannot be reached by merely Hitherto these dies have been increasing' the power of the blow by adding to the weight of the hammer. The new rewhen formed from cast iron, or from a comparatively soft metal, such as bronze, gold, -silver or even copper, to be broken or crushed by contact with the dieblock,is avoided, and also that the m'ost delicate parts of themos't difficult and nest work are brolught out'v ac-I curately i-n the die block and aperfect reproduction of thepatrice secured,ths beingtrue even where the relief andy intaglios of the patrice are very sharp and deep and finely drawn. The patrice passes so rapidly into the steel of the die block that it 'does not reit, the blow expending itself 'for the most part in the striking of the extended base of the patrice against the marginal top of the die block; and the high velocity of the patrice not giving suicient time for its breaking d own Perfect dies are thus securedwith great certainty and comparativelyslight cost even for the most complicated and delicate work.

The requiredvelocity may be given to the practical 'and eicient means known to me is that of a fall hammerdropping from a suiciently high elevation.v The velocity which must be given to the patrice at the moment of suits, and which -I' referto herein as a high degree of speed, is a' velocity of from aboutA twenty-five feet per second up to seventy-ve and Yone hundred, or even more', feetper second; and this lvelocity may befsecured by a ten feet upward. I A,

' In the'process above'referred to, upon which the present invention is afn improvement, it was proposed to use the/ordinary drop hammer employed in the arts having a fall of from two to six feet. The high degree of speed necessary to the practicey of my. invention drop hammer as' lheretofore commonly employed in' the arts; and I have found" it necessary to obtain specially constructed drop patricein any desired manner, but the mostl hammers of much more than the usual'height. v Ithave usedwith excellentresultsdrop ham- ./r'/

lsult is that all liability of the patrice, even v ceive enough of the force of the blow to injure away from the angles and sharp corners.

impact in orderto secure my improved re-l drop hammer having a clear fall/of from about i 9o y therefore cannot bjc/secured by the useof. the

face of the die block, now known or hereafter 15. devised, may b'e employed for the purpose. The most practicable and-best means known to meconsist in covering the face o't the die blockwith a close-fitting cap', and inclosing the die block and cap in an air-tight, close- -zo fitting casin g of suitable material before placing itin the-furnace. The die block thus protected and placed in the furnace is brought to such a degree of heat as desired. I find that the best degree of heat for this purpose is a white or welding heat, but other degrees ofheat may be employed. Theheated die block is then taken from the furnace, the inclosing hood is removed, and the die block is placed under the hammer; the .elose-itting 3o cap is then removed and the impactof the patrice is effected before exposure to the atmosphere can cause oxidation-of the surface of the die block. Sometimes it is possible to dispense with the inner .close-fitting cover where the reliefs are low and the surfaces plain, so that. the effects of oxidation can be.

removed from the die block lby the use of tools. Ido' not limit myself in carrying out the above mentioned operations to the use of 4o a vpatrice, made of any particular material or made in any particular manner. I prefer to make the patrice by casting in a suitable mold from a form or pattern, using any suit;

, able metal. The l'best 'metal known to me for the purpose is iron, .including under that term steel. I prefer, to use cast iron, adding thereto while molten about six per cent. of steel chips. -The processwhich is the subject-matter of my present application may be practiced 5o.'with very many forms of apparatus, and I .do

not confine the practice of the process to thev use of anyparticular form or construction. thereof.- I will however describe the arrest,l suitable form of apparatus now known to me' for the purpose. l

l In the drawings annexed .to this specificaF A tion and forming `ari-part thereof, Figure 1' shows vin section a. die block and the swage "or die holder inwhich the die block is held 6o while receiving the impression, and in eleva-v tion thehammer carrying the patrice and the guides between whichit works up and down,

the position of the parts being thatimmeditelynfollowing a 'blow of 'the hammer. Fig. 2 is a side view'of the samepartly'insection on line 2.-,2, Fig.3. Fig.3 isa plan view 'of the die holder and die block partly in section on line 3-3 of Fig. 2. Fig.- 4 represent-s mechanism hereinafter described for catching the hammer on the rebound, the clutches being shown withdrawn from that position in which they engage with the ratchets. Figs. 5 and Gare respectively longitudinal' and cross vertical sections, on an enlarged scale, of a die block, its cap and casing. Y

'The die block A is,.as I have stated, preferably of steel o r iron faced with steel, and is of rectangular orc'ircular or other desired form. The top surface maybe fiat, butI prefer to have it made with a central projection onfullness, as shown, sloping from the center to points'near the edges of 'the block. The object of this fullness isy to secure a greater degree of adaptability in the metal ofthe die block to the shape of the patrice than would v be possible if the' surface of the die block were plain. being upon the apex of the fullness of the-die block, this part' of the die block is free to adapt itself to theeonliguration of the patrice and to completely fill all `its recesses before.

the movement of the patrice is arrested by the contact of its iiatsurface with the face of the die block.- Moreover, lthisfullness in the die block permits the air to be driven from The first impact of the patrice the center outward frombetween thepatrice and the die block, preventing the inclosure of air between approaching surfaces,` the effeet of which would be, if it occurred,to keep the metal of the die from following into the sharp angles and recesses of the patrice and would more or less d ull the impression,- preventing the production of a sharply defined die. The block is provided with a cap a so shaped-as to closely fit its surface andis, thus' protected, inclosed injan air-tight caseof appro'priatefmaterial and shape. For this case I prefer to use sci ne refractory'material, such as plnmbago,.formed or pressed 'into shape. t

The form of case shown herein consists, (see Fig. 5) of a. plate b on which the die rests, and a cover c inclosingthe die block andresting upon' the plate bin such manner as to exclude air.

The channel tool or'die holder in which the die block'is held while being impressed consists, in the preferred form 'which I have shown lll-5 I.

v herein, of a solid block of steel d of suitable 'IA size, for instance three and a half feet long by .Y

twelve or thirteen inches wide and eight or nine inches high, in which is planed a channel Ig about four inches wide and half the -1 depth of block, vto receive thedi block.

Steel lreinforcingstraps e embracing the sides of the' block are shrunk on -and fastened by steel -bolts f passing-through the .body of. theblock. 'Other large bolts, four of which are shown, pass through the lower part of theblock at intervals ofits length for the pur-` pose ofstrengthening it against. th'e tendency to split longitudinally under the stress of t-he Ablow ol` the hammer. At each end', ,of the' block and just above thelevel of thebottom izov -of the channel arecut twe'slightly tapering fall and vice versa.

about fifteen feet.

key-ways h adapted to receive the tapering keys 'k which are somewhat longer than the width of the block and which form end bearings for the die block, or for packing pieces between the die block and the keys and are driven in to wedge the die block in place. These packing pieces z' are used for the purpose of adaptingthe` die holder to dies of dit'- ferent lengths. Packing pieces may be also inserted lengthwise of the dies to permit the die holder to .be used for die blocks of differrent widths. For certainty in centering the die block under the hammer, it is convenient to first drive one of the channel keys home, place the proper amount of packing between this channel piece and the die block to bring it into its prper position under the hammer, drop in the die block and wedge the die block in piace by driving in the other key against a suitable amount of packing interposed between the key and die block. Great strength in the die holder and tight and secure wedging ot the die block are desirable on account of the enormous spreading force exerted upon the die block by the blow of the hammer. It is in order to hold the metal of the die block up to the patrice, and thus insure 'a perfect impression,at the same time avoiding distortion of the die block, that'the die block is so tightly and powerfullyfconined. Y

The block d stands upon a suitable foundation between two-upright guides m, n, between which the -hammer o slides up and down, suitable power apparatus being provided for raising the hammer, and a suitable I trip operated from below'for permitting it to fall. The weightof 'the' hammer will vary with `the character of the work .to. be done and the distance it is caused to fall. Within 'certain limits reduction in the weight of the hammer maybe compensated by increased For ordinary light work, such as making dies for scissors, hammer heads, wrenches and other small tools, I prefer to fuse a hammer weighing Aabout one thousand pounds dropping from a height of The hammer preferably carries a hardened steel hammer block' p, adapted to enter the channelof the die holder, to the striking face of which is attached the patrice in any suitable manner. I find it most. con venient to fasten the patrice detachably, so

that its connection with the hammer. may be as plaster of broken by the shock ot impact with the die block andthe patrice left resting on or in the dieblock as the hammer recedes after the blow. This may b e done by the use of a cement, such paris which is the best cement known to me for the purpose, spreading the cement over the face of the hammer block in a plastic condition and applying thepatrice thereto; but the patrice may be fastened to the hammer'blcck in any other suitable manner.

` It is very desirable in carrying out this process to provide means forpreventing the hammer from making 'a double blow upon the die .shown in Fig. 1.

block. Theimpact of the hammer, when moving at high speed, upon the die block causes it to reboundand to fall back, striking the die block again with vgreat force unless some means are provided for preventingthe second descent of the hammer. The effect of such a second blow is frequently to destroyrthe die cut by theiirst blow since it will sometimes happen that two such successive blowswill not be exactly coincident with each other. This is the case where the patrice is attached permanently it is detachabiy affixed to it, as' by cement. In the latter case the patrice is sometimes partially pulled out of the die block before it is detached yfrom the hammer, so that, if struck by the hammer after the rebound, it would be liableto diverge from its original impression and spoil the die. The means which I preferably use for preventing the second blow of the hammer are shown in Figs. 1, 2 and 4 and consist of two ratchetbars q q', one attached to each of the uprights myn., and two clutches B pivoted upon bolts s siixedin thehamner and having on their lowerends teeth adapted -to mesh with the ratchets. To the hammer face is fixed a vertical mandrel t, the ends of which are held by clips luJ u. VAbout the mandrel is a cylinder E, the-head E' of' which has in it a hole through which the mandrel passes. The lower end of the cylinder lits loosely about a collar c, free to slide up and down on the mandrel. About the'mandrel is a spring a: held under a slight pressure, be-

tween the head of the cylinder and the collar.

Near the top of thezcylinder and on opposite sides are two external lugs y y. Eachof the clutches Bis provided with a pair of arms B B2. These arms B are so adjusted that when. their upper ends rest against the lugs y, y',

as shown in Fig.\4,the arms B2 support the collar 'v and compress the spring -The operationjof this device is asfollows: The clutches normally rest vwith their arms B against the lugs y as shown in Fig. 4, in which position the teeth ou their iowerends cannot engage with the teeth'on the ratchets q. When the hammer descends and vstrikes the die block the momentumof the cylinder E carries it downwardagainst the Vpressure ot the spring a: until the lugs y y release the arms B' and permit the clutches. to spring outward under the pressure ofthe spring acting through the collar u and the lower arms. B2, until the .parts assume the position .Thelugs y y' are nowcaught under the upper hooked ends of arms B. The cylinder is thus and the clutches 'are forced outward and drag along the teeth of the ratchets as the ham-v to the hammer, `and also where IOC held in its depressed position,

mer continues to rise on its rebound, As"v soon as the 'hammer ceases to ascend the'teeth o; the' clutches engage with' the teeth pfzthe ratchets and preventa second descentfWhen the hammer 1s to be again raised' the lower ends ofthe clutches B are pressed ltogether,

i v the patrice to-th 'e hammer block is advanwhich does not require a great exertion of force, and the cylinder E immediately returns to its normal place and locks the clutches l5 in the position shown in Fig. 1. Handles D are inserted in the lower ends-of the clutches for use in pressing the clutches together. \Vhi1e this is the preferred form of apparatus for preventing a second blow upon' the dieblock I do not confine myself to the use thereof, but may employ any apparatus suitable for the purpose, or mayuse the hammer without such apparatus.

In practicing my invention with the described apparatus the cap ais first applied to the die block, the die block is then inclosed in the casca-resting on the base b, and the incased die block is then Aplaced in the furnace and suitably heated. The die holder is then adjusted to receive the .die block and the patrice isattached to the hammer block; the heatedA die block is removed from the furnace, the casing taken off, and the die block dropped into the die space prepared for it in the die holder. The key is then driven home, wedging the die block between the packing pieces. The cap a is removed and immediately the hammer is tripped and drops, and the patrice is driven into the die block. The hammer rebounds and is caught by the clutches, and there suspended until it is againY raised. yWhere the patrice is attached to the hammer block by cement the force of the blow destroys the cement and breaks the connection; and the hammer block rises leaving'the patrice in the die. This method of attaching tageou'sfor a number of reasons; first, it is convenient and permits'patrices of different lsizes to. becentered upon' the face of the hammer block. Again, it is desirable in` many cases to leave the patrice in the die until the latter v has cooled, so as to effectually l Lprevent the access of" air to the surface of the 'die while hot.. This can bemore eectually done by leaving the patrice in the die than by filling the die with powdered charcoal which is a method of excluding the air sometimes resorted to.

After the dieA is cold its surface may be brushed with a solution of muriatic trice as the equivalent of motion of a patrice against a stationary die block.

An advantage of the process above set forth to which I wish to call particular attention is the fact above'adverted to that the highvef locity of the patrice at the moment of impact makes itpossible to penetrate the steel die block with a patrice fo'rnled of metals very much softer and more fragile, and therefore more easily worked, than a patrice cut from rolled cast steel which must be employed where the patrice is placed upon the die block iicult to make and much less costly, While at" the same time I obtain better results than can be secured by any other process.

' Certain features of the machine herein described are claimed in my applications, Serial Nos. 333,357 and 435,478, filed December l1,

1889, and June 4, 1892, and are therefore not 1 claimed herein.

Having thus described my invention, what I claim, and desire to protect by Letters Patent, is-

Y 1. The process of making steel dies, which consists in preparing and heating a` suitable steel or iron and steel die block and causing the patrice to move at a high f degree of speed as hereiubefore defined, and while so moving to strike thedie block and cut the die yat a single blow, substantially as described.

steel or iron and steel, die block andpreparing-a patrice from a metal which is comparatively soft or capable of being readily brought to the desired shape, as cast iron, and causing the patrice to move at a high degree of speed as hereinbefore defined, and while so moving to strike-the die block and cut the die at a single blow, substantially as set forth.

In testimony .whereof I have hereunto set vIO my hand in the presence of two subscribing l witnesses. i

. `Witnessesz f, J. J'. KENNEDY, EDWARD R. WOOD.

GEORGE F. oHA/lyvPNEY. y

Images