US2603987A - Apparatus for making cartridge casing blanks or the like - Google Patents

Description

July 22, 1952 G. A. LYON 2,603,987

v APPARATUS FoR G CARTRIDGE CASING BLANK S T H E L I K E Original Fi 1111111111111 2 Patented July 22, V1952 APPARATUS FOR MAKING CARTRIDGE CASING BLANKS OR THE LIKE George Albert Lyon, Allenhurst, N. 'J

Original application January 12, 1942, Serial No.

426,453, now Patent No. 2,360,354, dated Oc- `tober 17, 1944. Divided and this application March 18, 1946, Serial'No. 655,119

4 Claims.

cylindrical metal object from a square blank or slab. A Y

Another object of this invention is to provide an improved coining die for shaping fromy a predetermined, blank a coined circular article of predetermined depth and inwhich the metal is caused to fiow during the coining operation in such a-di-rection as not to affect detrimentally the get-upof the `article preferably made from 4thecoinedv blank. l The subject-matter of this invention has been divided from my Patent No; 2,360,354 issued Octobery 17 1944, and isa continuationof my copending kpatent application, Serial No.- 471,665, led January 8, 1943, now abandoned. i

f. Heretofore, in the vmanufacture of 40 mm. -Bofors cartridge casings and the like, it has been the practice to punch out circular fiat blanks from `slab'or Vsheet material, each blank having a pre determined-.weight and vmetal content commensuratewiththe size of the casing to be made :therefromby: subsequent cupping of the blanks and drawing of the resultant cups. Such round blanks ca nrobviously not be punched out contiguously. A networkfof slab material is left between thefpunched-out perforations. In .particular, when heavy sheet orslab material Lis used, it' is-necessary to space eachround blanka considerable-distance froln'they, adjoining blanks in orderto have sufficient remaining material for aholddown during the cutting through of the thick stock.- Thusl from a brass slab 91% inches long,; 12%.; inches vrwidesand 0.687 :inch thick, weighing259-46 pounds, 62 round blanks each v,weighingw2-r215 pounds may,A be punched. These 62 -;blanks wil1,weigh-137.33 pounds, A The part of y theslab left as scrap Vafterthepunching operationwill weigh 122.13 pounds.-y In other words, the, punched-out round'blanksamount to ,only53 percent of the original slab material and 47 percent ofthe slab material is wasted as scrap.

Actually, it has been the practice for the brass foundries to roll brass into slabtform, annealthe rolled slabs thoroughlyfthen punch out the round blanks and anneal the blanks for three hours. Such-,prolonged annealing .is made necessary by the-severeworking o f the marginalv blank `portions in the punching operation and leaves the blanks with a coarse crystalline structure. The annealed blanks lare shipped to the casing manufacturer for further Working,

, In the previous practice of fabricating cartridge cases, the round blanks have been cut from heavy slab material having a thickness equal to the required bottom thickness of the finished casings. Cartridges for present day anti-aircraft guns are provided with head or closed ends much thicker thanthe side walls, which are made as thin as possible in order to keep down the weight ofthe cartridges, for enormous gas pressures are generated within the cartridge cases on firing. The tapered form of the cartridge cases tends todirect the gas pressure against the bottom and base of the casing. Further, the base of the cartridge casesis not supported laterally by the gun bore, which is countersunk to render the cartridge base accessible to ejector fingers. Asaconsequence, the bottom and base ofthe cartridge cases must be made thick enough to prevent rupture on firing. When, according to the standard prior art method, round blanks are punched from thick metal slabs, the cutting or punchingof the thick slab results in a so-called drag on the slab material at the edge being cut, which is made evident y `made irregular for some distance inward. These irregularities remain in the margin of the punched-out part through all the subsequent cupping and drawing operations. Asl a consequence, it `has heretofore been found necessary to draw out the casing to a length much greater than that desired in the final cartridge and then to cutoff between four and five inches of the open end so as to remove from theA casing material char,- acterized by va roughened surface, overlapping seams, and more or less 'free slivers or burrs of metaLf4 Further, portions of this irregular or rough part of thevblank are likely to break off in one of the drawingdies and may then so damage `the casing. lfas tov necessitate its rejection. Due

to the rapidity with which these casings are drawn on a large production basis, such abrokeno piece of metal in the die, if not observed, might easily damage many casings before its presence casingswhich is 'of suchconstruction andarrangement that a square blank can jbe initially used instead of a round blank, and whereby some blank is caused to ow in such radial direction as to form a raised edge and to flow other metal inwardly to form a centrally bulging button have ing margins tapering to the raised edge; the raised edge being so formed that it may be conveniently trimmed thereafter from lthe* coined blank leaving a circular coined blank which may raccents? 4 The coining assembly includes an upper male die member 20, a lower die member 2|, an indexing ring 22 cooperating with the lower die member 2l to form a female die member, and

an indexing plate 23 from which the indexingv ring` is suspended. Themale die is generally cylindrical, terminating .in a constricted end portion having a round end face including an outer annular flat surface 24 surrounding a frusto-conical annular surface 25 within which an annular surface 26 slopes toward a shallow central recess 21. The lower die member 2l is also generally cylindrical, terminating in a constricted end portion having a round end face be thereafter cut and drawn-into the desiredVV cartridge case shape.

In accordance with other features of the in-v n vention, there is provided, in a coining apparatus of the aforementioned character, cooperable die members so constructed and interrelated as to act on the blank in such a way thatthe vma'- terial thereof is distributed and so work-hard'- ened with the central portion of the blank as t0 provide for the enormously concentrated strains vtov Iwhich thebase and'bottomV of a cartridge made from the coined blank will be Vsubjected on the firing of shells made using such cartridge ca sings.

Other objects and features of this invention will/more fully appear from the following detailed description taken in connection with rthe Aacc'ompa flying drawings, which illustrate a single embodiment thereof, and in which,

Figure lis a vertical Vcross-sectionalY `view the marginal edge has been trimmed therefrom;v

Vand

Figure 4 is a vertical cross-sectional view through a cup formed by a suitablecupping A01peratio'n from the coined blank shown in Figure 3,"and which cupping operation constitutes the initial upsetting operation in the series of operations employed to, draw a cartridge casing therefrom. f

Asshown onthe drawings: Y As noted before, it is the aim .of this invention Lto use a square blank sheare'd from a'slab of k'metallic stock, such as brass or steel, instead o f a circ'ularly cut blankv in the forming fof vdrawn articles, such as Vcartridge'casingsr i Y 1 fhavegfound that the use lof such a'fblank `enablesfcertain metallurgical advantages inthe distribution of the strains 'and crystalline kmakeup ofthe article and, moreover, enables a saving. ingas much as fifty percent of the heretofore waste material. u After a blank Vof the desired size andthickness has been cut from" a slab, it is 'pla-ced' in `my Ynovelcoining apparatus, shown in Figures 1 andg2; with its corners ntting in the 'square corners ofthe lowerdiemember shown -in-Aliglure 2.V I Shall now proceed to describe the coiningclies.VH r

Aequal in size and aligned vwith the end face of Vthe male die member 20 and formed with an -outer annular flat surface 28 coextensive with the surfaces 24 and 25 and a shallow central 'recess having walls 29 sloping very gently toward a at bottom 3i). The indexing ring 22 is countersunk on -both sides of the constricted endv portions of the die members 20 and 2l. The' indexing ring isY flanged for suspension in an aperture l'32 vin the indexing `plate '23. Registering bores 33 and 34 provided, respectively.,

in the indexing ring ange and in the indexing plate accommodate coil springs 35 tending to lift the indexing ring away from the indexing plate. Such lifting movement is guided by headed pins 3B screwed into the indexing plate margin -aro'und thev aperture 32 and extending `th'rc'iugh close fitting bores 31 in the indexing 'ring flange, the pin heads limiting upward move ment of the indexing ring.

VFor cooperation with the die members 20 and '2, the indexing ring extends between the Surface 2'8` in the lower die member V2| and the surfaces 2li and 25 on the upper male die member, having its upper inner edge brevelled for `avoiding impact thereagainst ofi the male die member surface b25. Y At Vo intervals the' inner surface of the indexing ring is recessed, 'as indicated by the reference*numeral '38,v to receive the corners of a sduare blank. *The indexing ring and itsl iref cesses 'are sro proportioned that the square blank iswedged-fast therein. When the male die mem'- Vloer 20 is approximated to the die member 21 `and the indexing ring,v a 'square blank being wedged rast in itneiatter, then the sloping 'sur-facesse and 29'bri1'1`gf`ab0`iit an ri'ward radial 'o'WfOf blankv metal yfilling'the recesses in the faces of the die members 20 and 2i. Atthes'ametime, the 'marginalmank material between the brani; 'corners isforced radiallyv outward ;V Vthe resulting 4metal article being designated by the 'reference numeralfao and vcomprising 'a rmargijnm mash" portion; derivedA from ma inal lblankl material cncmdingthebnnk corner )7;

l 'This fnsrwpprtion extends inwardly toa line 4I generat'edb'y the edge forming the transition'fromth'e ustoconicalrsurfac'e v25 in the 'male fdiem'ember tothe sloping surface V26.V vThe article 40, when 'trimmed Valong the Vline M, 'forms the! button `4 5 "of Figure 3 having tapering margins "4t-and a central bulge Al-fonone broad face. Thifsbu'tton does not contain a'n'ly marginal blankrnateriall whose internal structure' has `been affected by` the original slab shearin, zj,Vv lank forming operation, for all f'sch material has been forced joutside the linefl linthe co'i'ningoperation."V j 'g -v Y 'riler frenetica or the index' plate in the .aber/e described taining and trimming operations A'is-te -Carryl the" indexring With the blank wedged f'a'st therein i from Athe 'various 'y bpe'ratingA stations' 1 at which-,respectively placing 'of 'a blankinthirmg,

coining. and trimming are effected. It vshouldbe notedv that the index plate vcarries the'index ring andthe .blank Wedgetherein asa unit from one stationtoanother.: .The springs 35 lift the index ringoi the diemember 2| after the coiningnoperation; when the male diel member .20 recedes fromthe die memberZ the heads ofthe pins 36 limiting: this-upward: movement of the index ring atfa point Where the index ring still remains centered inthe index plate aperture 32'.

ABcfo'rethe button 45- is subjected vto a further iworkiiig, itis annealed soas to compensatefor the wall 5| of the cup and the central button portion including the bulge 41 `have been formed into the bottom 52 of the c up. The squeezing or coining operation having"v established in the coined'blank a grain or crystal structure patterned after the spokes of a Wheel in thatthe -linesof flow-of the crystals-extend to and con- -vergeat the center of thefblank, this same grain structure iscarried over into the cup 50,'the lines of the grain structure extending from thecenter of ythe bottom 52 around and up vertically through the sidewall 5| so that the lines ofthe crystals all extend in substantially the same direction. This eliminates a potential point ofv weakness at the junction of the side wall 5| with the bottom 52 present in conventionally manufactured cartridge cases.

It should be noted that the inside side wall surface extends straight and with but little divergence from the vertical down to the line 53 in the base region and thereafter extends, still straight, but with slightly less steepness, to the bottom of the cup. The side wall 5| below the line 53 is thus made somewhat thicker than the rest of the side wall for the purpose of increasing the strength of the cup base.

After the aforesaid cupping operation, the cupped article is thereafter subjected progressively to a series of drawing operations for the purpose of elongating the wall of the cup to the length desired in the ultimate cartridge casing. Since such drawing operations do not per se relate to the coining apparatus herein claimed, it is not believed necessary to describe such operations in detail, especially since they are described and claimed in the aforesaid Letters Patent and pending application.

The internal or metallurgical make-up of the article is determined by the coining operation and is preserved during the subsequent operations so that the fibrous metal structure extends radially from the center of the bottom of the article up through the side walls.

Actually, I nd that cartridge cases made by the use of my coining apparatus after the nal annealing and normalizing operations have a hardness in the head and base region ranging from 115 to 105 Rockwell F While the straight open end section has a hardness of from 95 to 8'7 Rockwell F.

I iind that by using my invention the marginal trimportion to be scrapped amounts to about seven percent of the total stock used and that this figure actually includes whatever material from the end of a slab that may have to be scrapped.

A slab 121/2 to 12% inches wide and from 'l to 10 Y from the rim of the recess, another die member feet long may suitably beused forcutting .blanks 4 inches square and inches thick, a A93percent yield of `such-blanks being obtained. f Another, 21 percentofthe. original slab material.- .is trimmed off the blanks after the.coining loperation,;sothat the total amount of wasted'slab materialzis28 percent as against the nearly;50 percent-waste of slab material inherent in the priorart method.v E;

The comparative cost of making blanks according to the. conventional methodandaccording to the present invention can be computed ,asfollows 500,000 pounds of rstandardblanks can be fabricated from=r1',000,000 pounds of slab. metal,.1-io'r 2.11/4 cents .per'pound, .being wor-th..$l0,6,250.00, and 500,000 pounds of scrap..being obtained fas .a by-product. According to thepresent invention, 1,000,000 pounds of slab-material iyield 720,000 pounds of. the 'novel blanks togetherfwith 280,000 pounds of scrap. Tothese 280,000 pounds of scrap another 220,000 pounds, worth-$21,175.00 at. 9% cents .per pound, mustbe added to have-.500,000 pounds `.of scrap for a newbatch. lAdding-this $21,175.00 .to the.$.106,250.00.cost of the.- 500,000 pounds of standard blanks gives. a cost figure. of $127,425.00 forthe.720,000 pounds .of novel blanks of itherpresent,inventiomfwhioh consequently will ycost 17.7" cents per pound' fcon-ventional blanks weighing .2.215 pounds .each will .cost 47 .07

cents. each, while thenovel blanks each.l weighing 2`.13.=pounds willi cost.v 3'7v.70.:cents apiecexfl .'Ihe saving-will bei9.37`cents per blankwhen-oper- :ating according tor vfthe present invention.: ther, since the use of my present invention increases the yield of blanks from any given amount of slab material by 44 percent, the number of slab cutting, blank forming operations is reduced considerably.

It should be understood that the foregoing embodiment of my invention merely serves to illustrate the application of the principles of this invention, which are not-limited to the speciiic example described. Thus, pentagonal or other polygonal blanks can be cut contiguously from slab material and coined in dies having indexing rings with an appropriate number of recesses for receiving the corners of the straight-edged blanks which are then trimmed, cupped and drawn, upset, tapered, and flanged to form the desired cartridge case.

I claim as my invention:

l1. In a die for forming a cartridge case blank from a straight edged ilat metal slab, the combination of a male die member having -a lface centrally recessed and marginally tapered away from the rim of the recess, another die member having a face opposed to and coextensive with the male die member, and an annular die member having an inside recessed at circumferentially spaced areas to receive the corners of said slab in wedgedfast relationship, said annular die member being interposed between the margins of said male die member face and said other die member face, to form with the latter die member a female die member capable of directly cooperating with said male die member to coin and squeeze said metal slab into a button having a thickened center tapering radially and raised extreme margins containing all the edge material of the original slab.

2. In a die for forming a `cartridge case blank from a straight edged flat metal slab, the combination of a male die member having aV face centrally recessed and marginally tapered away having a face opposed to and coextensive with the male die member face, and anannular die .7. member having an inside recessed at circumferentially spaced areas to receive thecorners'of said slab in. wedged-fast relationship, said .iannular die. member 'being interposed between .the margins of said male Edie member `face and said other diemember face, to form with the latter die member a female .die member capable .of directly cooperating with said male die member to coin and squeeze said metal slab into a button having a thickened center tapering radially and raised extreme margins containing all the edge material of the original slab, said rdie further including means for guidingly lifting said annular die member to a predetermined level above said [other die member after. each coining and squeezing operation.: y f- Y Y 'Y V3. 'In a die forV forming a cartridge case blank having athickenedv center tapering radially to a thickened edge from a at straight edge metal slab and including a male` die member having iaterminal. face with a central recess and margins tapering away. from the rim of said recess, the improvement including a ffemale .die member alignedv with said male; die'member fordirect cooperation therewithiand-including a member having amarginally vflat face opposed to and coextensive with said male die member as Well as an annular member having an inside recessed `at :circumferentiallyvspaced areas to receive: the vco'rnerszof said slabv in wedged-fast relationship andseated on the at margins of the rst mentioned female adie vmember face `to `limit lateral file of this patent:

8 flow of slab material. when the male die member isapproximated to saidlfem'ale die member. I

V41.4111 a die for forminga blank forv a metallic article from alpolygonalat metallic blank,.in combination,. directly cooperablev.- alignedzdie members having opposedfaces, one of .said faces .being centrally recessedand the other facehav- UNITED STATES PATENTS Number Name` -Date Y. :503,354 Pearson, Aug. 15,1893 521,178. Porter 1 June 12,1894 937,749 Andrews r.-; Oct. 2.6,.'1909 1,434,190 Bird -v Oct. .31, -1-922 1,857,708 Benedetto Maylfll), 1932 y2,014,605 f Zimmerman Sept. 17, 19.3.5 .2,360,354

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