US2490926A - Blanking and cupping die unit - Google Patents

Description

13, 1949 R. E. sLATER y BLNKING AND CUPPING DIE UNIT Filed June l, 1945 I i||||||||||||l Il.

w v. "5 2 i 9 TER AGENT INVENTO-R RAYMDND E. 5L

BY% z l Patented Dec. 13, 1949 BLANKING AND CUPPING DIE UNIT Raymond E. Slater, New Rochelle, N. Y., asslgnor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation ol' Delaware Application June 1, 1945, Serial No. 597,076

2 Claims. (Cl. 113-42) The present invention relates to a die, particularly a blanking and forming die for producing tubular metal cups, such for instance as are used in the formation of cartridge cases, battery cups, or other ammunition components. An object of the invention is to provide a die wherein steel or other suitable sheet metal, having its grains or fibers directionally oriented, as distinguished from a random orientation, may be employed, and wherein the resultant drawnvcup will have a substantially smooth or non-scalloped mouth edge, which has heretofore only been possible with the use of metal having a random orientation of the grains or fibers.

The orientation of the grains or fibers of the metal results from cold rolling, which has the tendency to orient the grains or fibers in the direction of rolling, and when this type of metal is drawn in a die the drawn cup has a characteristic scalloped edge consisting of four ears or scallops located at substantially 90 to each other. Further drawing of the cup will cause the scalloping to move down the lines of weakness, which have occurred because of the cupping operation, so that these lines of weakness, retained in the cup throughout further drawing thereof, may extend down into the body portion of the cup even after the scalloped edge has been removed by the cutting oi of a relatively wide band. In the case of ammunition components, such as cartridge cases, firing may cause the case to split along these lines of weakness. In the case of ilanged battery cups the lines of inherent weakness may cause splitting as the edge flange is turned over.

It is proposed in the present invention to provide a die wherein the edge of the blanked disc is subjected in the die to an ironing or swaging action which has the effect of changing the directional properties of the metal at the edge of the blank, creating therein a compacted peripheral area in which the grains or bers have a random orientation. The edge of the blank which becomes the mouth portion of the drawn cup is thus prevented from developing the characteristic scalloping, and has the effect of sealing olf the usual lines of weakness and the potential fracture starting points.

With the above and other objects in view, an embodiment of the invention is shown in the accompanying drawings, and this embodiment will be hereinafter more fully described with reference thereto, and the invention will be finally pointed out in the claims.

In the drawings- Fig. 1 is a vertical sectional view of the die and its cooperating punch, according to the illustrated exemplary embodiment of the invention, a piece of sheet metal, from which the disc is to be blanked and cupped, being shown in relation to the die.

Fig. 2 is a similar view, showing the disc blanked from the metal sheet.

Fig. 3 is a similar view showing the disc pressed into the die to the point where the ironing or swaging operation upon its edge is performed.

Fig. 4 is a similar view, showing the drawing of the cup from the disc.

- Fig. 5 is a similar view showing the completed cup carried through the die and the drawing punch disengaged therefrom through its upstroke.

Similar reference characters indicate corresponding parts throughout the several figures of the drawings.

Referring to the drawings, the die, according to the illustrated exemplary embodiment of the invention, comprises a die holder I0 provided with a downwardly converging tapered pocket I I having a central opening I2 in its iiat bottom. Within the die holder there is engaged a die block I3 having a. tapered periphery fitting the tapered wall of the pocket H and normally having its base spaced above the base of the pocket II, as at M. The die block is retained in the die holder by means of a locking ring l5, engaged in an annular groove' I6 in the die holder and projecting into a shouldered peripheral recess Il at the upper end of the die block, the ring lnormally engaging the base of the shouldered recess, to prevent upward disengagement of the die block, and the recess being open above the ring to permit downward movement of the die block in the holder, as will presently more fully appear. The work receiving opening through the die consists of a slightly tapered downwardlyl converging upper portion I8, an arcuate inwardly and downwardly curved guide portion i9, and a cylindrical die land 2B having a beveled clearance recess 2l at its under side, the arcuate guide portion i9 blending with the tapered upper portion I8 and extending to the die land 20.

The die holder l0 is rigid and non-elastic, being suitably hardened and of suilciently massive structure as to withstand any dimensional change in its pocket Il when downward pressure is applied to the die block through the downward impact occurring upon cooperation of the punch therewith during the blanking and forming of the cup. The die block is formed of a suitably hard- I from the bottom of said recess vwhen unstressed,

said die having a downwardly converging work blank receiving aperture, a blanking punch of less diameter than the maximum diameter of said converging aperture, and means to move said punch into said die aperture to blank a disk from a sheet and advance said disk into the work receiving aperture of said die and thereby simultaneously moving said die downwardly in said recess to compress said die radially and reduce the diameter of said die aperture so as to change the directional properties of the metal in the periphery of said disk which is in engagement with the walls of the die aperture.

2. Apparatus for the production of smooth edge cups from sheet metal having directional properties comprising a blanking punch; a blanking die comprising a die block having therein an aperture in axial alignment with said punch, the intersection of the wall of said aperture with a planar face-.of said die block forming a shearing edge cooperating with said punch, the diameter of 'said shearing edge being greater than the diameter of said punch and the wall of said aperture sloping inwardly from said shearing edge to form said aperture to progressively reduced diameter, the inclination of said aperture wall being such as to enable said punch to enter said decreasing diameter aperture a distance exceed- 6 ing the thickness of said sheet metal; and punch actuating means to advance the punch toward said shearing edge to shear a disk from a sheet interposed between said punch andsaid die and to further advance said punch into said die aperture to thrust said disk while transversely subs'tantially undeformed into the reduced diameter portion of said aperture, thereby compressively straining and altering the directional properties of the edge portion of said disk.

RAYMOND E, SLATER.

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

UNITED STATES'PATENTS Number Name Date 37,189 Westlake Dec. 16, 1862 94,857 Allonas Sept. 14, 1869 181,356 Milbank Aug. 22, 1876 1,043,520 Higgins Nov. 5, 1912 1,692,902 Moltrup Nov. 27, 1928 2,150,708 Andrews Mar. 14, 1939 2,415,940 Eckstein Feb. 18, 1947 FOREIGN PATENTS Number Country Date 5,112 Great Britain Apr. 6, 1887

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