US2426289A

US2426289A - Method of making cartridge cases

Info

Publication number: US2426289A
Application number: US398174A
Authority: US
Inventors: Robert H Wallace; Alex W Knudsen
Original assignee: Midland Steel Products Co
Current assignee: Midland Steel Products Co
Priority date: 1941-06-14
Filing date: 1941-06-14
Publication date: 1947-08-26
Anticipated expiration: 1964-08-26

Description

lvg 26, 1947. R. H. WALLACE ETAL A 2,426,289

-METHOD OF MAKING CARTRIDGE CASES ALEX W- KNUDS'EIN:

ROBERT H. WLLAC Aug. 26, 1.947. R. WALLACE ErAL 2,426,239

METHOD OF MAKING CARTRIDGE CASESl Filed June 14, 1941V 2 sheets-sheet 2 F|G.2 2o .5 I4 756 4 :alp s 3 "":l' l: I

I6 n I l ls l 2o '5 0 1364 ls 14 :s

,A l l ls l l mvENToRS ALEX W. KNUDSEN "Y` RoERTwwALLAcEJ Patented Aug. 26, 1947 A.

'NED STAT-ES METHOD F MAKING CARTRIDGE 'CASES Application June 14, 1941', Serial No. 398,174

.3 Claims.

This invention relates to new and useful improvements in the vmethod of Vmaking two piece cartridge cases.

An important object vof the invention is to :provide vmethod and means for press fitting, squeezing and upsetting theparts of 'the case together to form a double seal to effectively withstand high gas and hydrostatic pressures.

Another important object of the invention is to provide a cartridge case made of two simple parts to replace the more 'expensive `one-piece drawn cases, which two `parts lare most effectively locked together with a new method of manufacture.

Other objects and advantages will become apparent during the course of 'the following description.

In the accompanying drawings forming a part of the description and wherein like parts 'are designated with like numerals throughout `the several views,

Fig. 1 is a longitudinal section through the improved cartridge case showing the same 'as it takes its assembling position between dies,

Fig. 2 is a similar View showing an intermediate step in the method of connecting the `case with the base,

Fig. 3 is another similar view showing the i-nal step in the method, illustrating'the nalassembled condition of the parts,

Fig. 4 is an enlarged fragmentary section of the case and dies of Fig. 1.

Fig. 5 is an enlarged and magnified section of the case and dies as shown in Fig. 3, illustrating the final form of the joint between the case and the base.

Referring now more in detail to the accompanying drawings and to Figs. 1 and 4, wherein for the purpose of illustration is shown a 105 millimeter cartridge case, the numeral I designates an elongated cylindrical body or .metal cartridge case about fourteen inches in length, preferably made of seamless or welded tubing Vhaving an O. D. of approximately 4% inches, and of uniform wall thickness of approximately le of an inch. Tubing having a longitudinally welded seam has been found to give excellent results and as not being impaired at the seam in the yflanging and `processing steps.

The cap or base end of the Ycartridge case or annulus I is formed in any suitable way, but preferably by spinning, with an inwardly tapered portion 2 bent on a ,1 5 inch radius at vapproximately an angle of 45 degrees, the end `'of which .portion is bent again on a ,-16 inch radius into an axially 'extending portion having the same wall thickness as the -body of the case and an I. D. of 13% inches anda length of 1/8 inch concentric with the main body -of the case. This bending of Ithe Iend 'of the lcase forms it with the integral compound curved -

ange

2 and 3 as illustrated.

vThe -b'ase 'of the cartridge case is made of a disc cut from round bar stock, or it may be a stamping, forging, casting or the like. In any `event it is formed on its inner face with an axially extending 764 inch wide groove 5 formed with concentric axial iianges 6 and l. The inner flange 5 has an O. D. of 32%2 inches and is much longer than the outer flange l which stands Tse of an inch 'from the outer face of the base to the tip of the ange, while the inner ange stands l inches .from the same face of the base to its tip. The base also has an annular collar or flange 8 and a central inwardly extending boss 9 which is bored or tapped for the fuse capy of the primer charge. The outer face of the outer flange 'l is tapered at 4an angle of 7 degrees while its inner face has a '45 degree angle. The outer face of @ange t is .perfectly cylindrical and normal to the base, while its inner face at its tip is inclined at 'an angle of 15 degrees to merge into its transverse end with a Tg inch radius and into base 'd 1on a -g inch radius. Thus the base is provided with a groove 5 which is 1/54 of an inch wider than the wall thickness of the flange end -3 of the 'case to freely receive such end and to provide for rapid centering and alignment thereof 'as well las to provide for the subsequent thickv4ching or upsetting of the end within such groove. The method of assembling the base t on the case I, is to insert the latter in a slide t ring die Il) which in this illustration, has a die cavity terminating in a 20 degree angle bottom I2 to bac-k up the outer iiange 1. This ring die is seated in a ca vity in the upper end of a hollow stand I3 and is held by a ring retainer plate secured tc the stand by screws It as shown. When the case :I is inserted through the ring die Il) and down into the hollow stand, it has a clearance with the .bore through the stand as illustrated, and the pro i'ectile end of the case is supported upon a spring pad, not shown, inthe base of the stand to permit .axial .movement of the case during assembling :and may Iserve to eject the case later in the usual manner. A 4male die .post I5 is disposed concentric and longitudinally in the hollow stand to removably support the male die Il on top of the post by means of a screw I8 and within the female die with clearance therebetween for insertion ofthe case. The upper portion of the male die Il is formed with a convex nose swung on a 1/2 inch radius merging into an annular shoulder l 9 arranged a distance below the cavity I2 of the female die so that the cylindrical wall of the female die rmly backs up the cylindrical case during the processing.

The base il is then placed upon the case with the flange 3 entered in the groove 5 as shown in Figs. 1 and 4, and with the tip of the inner base flange engaging the convex surface of the male die Il and the end of flange 3 bottomed in the groove 5. The punch or ram 2!) of the press is then lowered to engage the base to move the case down through the ring die Iii and into the stand i3. As the base and case are being forced downwardly by the ram, the tip of the inner flange S of the base is first ilared outwardly by the male die I?, into engagement with the case I below the cavity I2 in the female die IQ, as shown to advantage in Fig. 2. As the case is forced farther downwardly into the female die I0, the nose of the male die il causes the inner ilange to progressively pinch or squeeze more and more of the case against the female die with longitudinal and radial outward pressure. This causes the metal of the case in the area between the inner flange ii and female die to crowd or flow longitudinally into the

flanged portions

2 and 3. This longitudinal displacement of metal causes the flange 3 to upset and increase in wall thickness above that of the original case I to pack and completely ll the wider groove 5 in the base.

It will be appreciated that the inner flange 5 of the base has its inner tip surface beveled for coordination with the curvature of the male die so that the. flange will be progressively moved with progressively increasing pressure into engagement with the case, to iron this portion of the case longitudinally and against the wall of the female die and against the outer flange 'l which backs up the flanged portion 2 of the case, whereby the displaced metal will be squeezed into and thicken the extremity 3 while portions of the two ilanges are being simultaneously pressed toward one another to firmly lock this thickened iiange into the base. When the outer flange I moves down into the female die cavity I2, it is pressed inwardly to closely engage the flange 2 and densify molecular structure of the flange 1. As the 1/2 inch radius of the maley die I'I bottoms against the 1%@ radius of the base 4 it will be seen that the base portions of flange 6 engaging the

flange portions

2 and 3 will be thinned and compacted firmly against and lock the thickened case flange in its space between the nanges 6 and l. In the final pressure stage of the press, the shoulder I9 of the male die engages the extreme end of the ilange 6 to deform it into a thin annular fin or flange 22 which seals against the shoulder formed in the case and serves as a illl or reinforcement for the end of the thinned portion of the case.

After the dies have bottomed and have formed the joint as shown in Fig. 5, the ram is elevated, and either the spring pressure pad or the male die can be automatically moved upwardly to assist in ejecting the shell. Thereafter, the base 4 is machined down to the dash line 25 shown in Fig. 5 to ilnish its exterior, or the base may be pre-shaped to nal form before being attached to the case.

The grain or fiber of the metal base 4 extends lengthwise of the flanges and is compacted in the outer flange adjacent the flange 2 while the grain of the inner flange 6 is compacted and follows the contour of the compound bend of the

anges

2 and 3 as best shown by the dot and dash lines in Fig. 5. Any stress imposed upon the joint formed, creates leverage inthe vicinity of the two points E3 and 2@ at opposite surfaces of the ange to create a compound compression seal. Hydrostatic pressure tests prove the joint invulnerable and show that the cylindrical contour of the case is maintained about 1A; of an inch beyond the iin 2 and toward the projectile end of the shell indicating the supreme strength of the joint under tests which are so severe as to actually bow the case outwardly.

While the parts of the cartridge case may be made from any kind of metal, the present invention was devised in order that it could be efcaciously made of steel to replace the more expensive one piece drawn brass cases. In this connection, the cylindrical body I of the case is preferably made of steel tubing possessing a single longitudinally extending welded seam for effecting economy of materials in the construction of the case. The method of processing the device, and its construction were conformed, to compensate for working of the metal to obviate any danger of impairing or opening the welded stock, so that this less expensive material could be utilized to economize in the manufacture of this essential defense material. The case is made simply in two pieces which are united very rapidly in a manner to provide a case which is more resistant to impact than the former brass cases, and is stronger at the joint than former multiple piece cases. The cases can be rendered rust-proof in various ways, so that they can be stored for indefinite periods or reused, and one eillcacious method is to electro-plate the cases with a thin coat of copper when completed.

It Iwill of course be appreciated that the invention is not limited to the production of cartridge cases, but may be employed as a joint of general application between any form of annulus and end closure. It will also be understood that various changes in the size, shape and relation of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

We claim:

l. The method of uniting a metallic annulus with a groove in a metallic base dened between a pair of spaced inner and outer annular flanges, said groove bein-g slightly wider than the wall thickness of said annulus, inserting the annulus into a conning die with its end inserted into said groove, moving said base and annulus axially relative to said die to restrict radial movement of said annulus, moving a male die against said inner flange to force the same radially outward to pinch the annulus against said confining die, and as the base and annulus are moved further to cause the inner ilange to progressively iron the metal of said annulus out against said conning die to flow the metal of said annulus axially thereof as the outer flange is moved to engage the confining die to thereby form a continuation of said confining die wall and thereafter exerting radially outward and axial pressure upon said inner flange causing metal of the annulus to flow toward the end thereof to thicken the same in said groove while continuing radial inward and outward pressures upon the outer and inner flanges respectively to lock said thickened portions of said annulus within said groove.

2. The method of uniting a metallic annulus with a groove in a metallic base defined between the high inner base flange having a straight outerwall and a low outer base flange having an inner Wall inclined outwardly away from the inner flange, bending the end of said annulus inwardly into a compound Ibend with a reduced inclined portion approximating the length of said inclined wall of said outer ange and terminating in an axially extending end, inserting said annulus for limited axial movement in a radial conning die with said reduced axially extending terminal of said annulus positioned in said groove between said inner and outer iianges, moving said base and annulus axially of said die while forming the end of said inner ange outwardly whereby its free edge pinches the annulus below said compound bend against said confining die, continuing the movement of said annulus axially of said die and exerting radial outward pressure on said inner flange to cause the same to be ironed out against the annulus backed up by said confining die, said outer flange being moved axially against said confining die to back up said annulus as said inner iiange is progressively squeezed inwardly and axially from its free edge thereby causing the metal of said annulus to progressively iiow into the reduced end thereof and to crowd its metal into said groove to increase its wall thickness while said two flanges are forced toward each other against opposite sides of the thickened reduced end of the annulus.

3. The method of mounting a steel annulus with a base consisting of providing a base having a groove wider than the wall thickness of said annulus, inserting the end of said annulus in said groove, exerting radially outward pressure upon that portion of the annulus immediately adjacent the inserted end of the annulus while confining the exterior of said portion of the annulus, and exerting axial pressure on said annulus, said axial and radial pressure serving to thicken said end in said groove above the original wall thickness of the annulus, and concurrently with the exertion of said axial and radial pressure, compressing the walls dening said groove upon the thickened end in the direction of said thickening.

ALEX W. KNUDSEN. ROBERT I-I. WALLACE'.

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

UNITED STATES PATENTS Number Name Date 192,676 Bullard July 3, 1877 1,826,544 Herbig Oct. 6, 1931 1,649,409 Jardine Nov. 15, 1927 1,805,255 Osterholm May 12, 1931 1,691,778 McDonald Nov. 13, 1928 2,018,683 Meyer Oct. 29, 1935 2,245,298 Proctor June 10, 1941 339,812 Ritchie Apr. 13, 1886 1,527,471 Clinchy et al Feb. 24, 1925 1,686,562 Jackson Oc'. 9, 1928 1,923,546 Lindemann et al. Aug. 22, 1933 1,292,359 Nelson Jan. 21, 1919 498,856 Overbaugh June 6, 1893 387,651 Maxim Aug. 14, 1888 1,157,269 Wall Oct. 19, 1915 1,482,932 Keiner Feb'. 5, 1924 546,936 Pinfold Sept. 24, 1895 750,394 Reynolds Jan. 26, 1904 1,620,728 Jackson Mar. 15, 1927 Re. 7,647 Allen May 1, 1877 298,696 Kynoch May 13, 1884 1,921,021 Bungay Aug. 8, 1933 2,112,673 Lewis Mar. 29, 1938 2,130,699 Reinartz Sept. 20, 1938 FOREIGN PATENTS Number Country Date Switzerland Apr. 24, 1912