US1368725A - Method of making cartridge-shells and blank therefor - Google Patents

Description

L. E. HOOKER.

METHOD 0F MAKING CARTRIDGE SHELLS AND BLANK THEREFOR.

' Petented Feb. 15,1921.

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METHOD OF MAKING CARTRIDGE-SHELLS AND BLANK THEREFOR.

Specification of Letters Patent.

Application led April 10, 1918. Serial No. 227,690.

To all whom t may concern Be it known that I, LESLIE E. HooKER, a citizen of the United States, residing at Lowell, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Methods of Making Cartridge-Shells and Blanks Therefor, of which the following is a specification.

This invention relates to the manufacture of cartridge shells, or other tubes, by drawing or extruding operations, and consists more particularly in improvements in the blank from which-the tubes or shells are made, and in the method by which said lblank is fed to the die in which it is drawn or extruded.

By reference to my prior Patents, Nos. 918,154 @if April 13, 1909, and 922,585 of May 25, 1909, it will be seen that the operation of extruding a. cartridge shell, o r other tube, starts with a cupped blank which 1s placed in a die, in which it is acted upon by a plunger comprising a central forming punch and an annular extruding punch.

No means is shown in said patents for feeding the cupped blanks to the die and, as a matter of fact, they were fed by hand. It was found necessary, in order to obtain a satisfactory commercial output from the machines, to provide some form of automatic feed. It proved impracticable, ho-wever, toapply any form of mechanical feed -which could be depended upon to supply and center the blanks over the dies with sufiicient speed and accuracy.

The present invention has solved the difficulty in the 'simplest possible manner by making use of the plunger,in extruding operations, the forming punch,-itse1f as the feeding means, thus eliminating all the complications of a mechanical feed and rendering the operation extremely simple, rapid and accurate. The punch descends, picks up a blank, carries it over the die, thus automatically centering it perfectly accurately, and descends again to carry the blank into the die. But in order to enable the punch to pick up the cupped blanks, I found it necessary to modify the internal contour of the same by forming therein three or more flat surfaces or ridges equally spaced so as to give the inner wall of the cup, or the upper part of said wall, a polygonal, or sen1-i-p0lygonal outline. The drawing or forming punch, which is of course circular in cross-section, then contacts only w-lth said three or more flat or raised surfaces, and that with sufficient force to assure the cup being lifted with the punch.

The semi-polygonal contour may be imparted to the cup in the operation of formlng it from the original planchet, or else the ordinary cupped blank may be submitted to a second operation to modify its internal shape. It is not necessary that the fiat o-r raised surfaces extend for the full depth of the cup, and they are preferably made V-shaped with the apex of the V located above the bottom of the cup.

1n addition to adapting the cups to be lifted and fed to the die by the punch, the described shape of the inner wall of the cup results in certain other advantages. Thus, the fact that small spaces are left between the punch and the circular portions of the wall enables the air and any excess of lubri cant to escape from beneath the punch. Also the fact that the punch contacts with the wall at equally spaced points only results in an automatic centering of the cup on the punch, so that the cups are always properly presented to the die in a true vertical position. This feature renders my improved form of blank useful also in ordinary tube drawing operations, whether the punch is used as the feeding means or not.

,l believe that I am the first to use the drawing or extruding punch itself as the means for conveying hollow blanks from their place of introduction into the machine to the die, and also the first to provide such hollow blanks with an internal semi-polygonal contour, by forming three or more Hat or raised surfaces on the upper part of the inner wall, to cause them to automatically center themselves on the punch and to enable the punch to lift them up and p-resent them in proper position to the die.

The invention is illustrated in the accompanying drawing in which- Figure 1 shows the operation of cupping a planchet in the usual way.

F ig. 2 shows the transformation of the cup so formed into my improved form of gig. 3 is a plan, and Fig. 4 a section, of the improved blank.

Fig. 5 is a plan view 0f the cup provided with ridges.

rammed ret. i5, raar.

Fig. 6 represents the formation of the improved cup in one operatlon from the planchet.

Fig. 7 illustrates the use of the punch as the feeding means to convey the cup from a feed table to the die.

In Fig. 1 a sheet metal planchet is shown at 1, and the die by which it is drawn, with .the cooperation of the punch 2,' into the cup 3 shown in dotted lines, is shown at 4.

Fig. 2 shows the same cup 8 placed 1n a die 5 in position to be acted upon by a punch 6, provided with V-,shaped fiat surfaces 7, equally spaced around the same, whereby my improved form of cupped blank 8, having V-shaped fiat surfaces 7 joined by the ori inal arc-shaped surfaces 10, see Figs. 3 am 4, is formed.

Fig. 5 shows the blank with raised surfaces or ridges 9 in place of the fiat surfaces 7 the number of which may be three, four or more, regularly interposed between the arcs 10 of the original circular contour, the essential feature consisting in the provision of three or more points at uniform distances apart around the circle with which points the periphery of the circular punch will contact, leaving small spaces between it and the remaining arcs of the circle.

In Fig. l6 the planchet l1 is converted at one operation into the new form of cupped blank 3 by means of punch 6, provided with the flat places 7, or suitably shaped to form the ridges 9.

In Fig. 7 the cup 8 is shown in position on a feed table 12 to be picked up by the extruding plunger consisting of the forming punch 13 and extruding punch 14, the raised position of the plunger being shown in dotted lines.

After the plunger is lifted with the cup thereon, it is moved laterally into the other dotted line position directly above the extruding die, consisting of the parts 15, 16 and 17, and, in its next descent, extrudes the blank into the tube 18. In this figure, the plunger is shown slightly above its lowermost positions, the tube not being yet completely extruded and the forming punch not having yet entered the cup to its fullest extent.

f Having thus described my invention, what I claim is 1. The method of makin a tube which consists in cupping a plane et, giving the inner wall of the cup so formed a semi- 3. The method of, conveying a hollow l blank of polygonal internal shape to a die which consists in feeding it into position to be entered by a punch, driving said punch into the blank, conveying said punch with the blank thereon into alinement with a die, and driving the same into said die.

The method of feeding a cupped blank to a drawing or extruding die which consists in .picking it up on a punch which contacts therewith at certain points onl raising said punch and moving it lateral y into alinement with a drawing or extruding die, and driving said punch with the blank thereon into said die.

5. A hollow blank for the manufacture of tubes, the inner wall of said blank having formed thereon a plurality of salient surfaces, to enable it to ycenter itself on the punch and be conveyed thereby into line .with the die.

6. A hollow blank for the manufacture of tubes, the inner surface of which blank is given a semi-polygonal contour whereby it automatically centers itself on a punch and can be conveyed thereby to the die.

7. A cupped blank to be drawn or extruded into a tube, comprising a bottom and an annular wall the inner face of the latter having three or more fiat surfaces, whereb it automatically centers itself on the puncii (alnd can be conveyed on said punch into the 8. A cupped blank to be extruded into a cartridge shell tube the wall of said cup having internally a semi-polygonal contour comprising three or more salient points joined by circular arcs, whereby the blank can be carried by the punch into accurate alinement with the die.

In testimony whereof I have hereunto set my hand.

LESLIE E. HOOKER.

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