US2762108A

US2762108A - Method for forming shell blanks

Info

Publication number: US2762108A
Application number: US314161A
Authority: US
Inventors: Robert G Friedman
Original assignee: National Machinery Co
Current assignee: National Machinery Co
Priority date: 1952-10-10
Filing date: 1952-10-10
Publication date: 1956-09-11
Anticipated expiration: 1973-09-11

Description

Sept. ll, 1956 FRIEDMAN 2,762,l08

Sept. 11, 1956 R. G. FRIEDMAN J METHOD FOR FORMING SHELL BLANKS Filed Oct. 10, 1952 3 Sheets-sheet 2 INVENTO I ROBERT G. FRIED BY EICHE); wATRs soafkmlvg/v /vilwvy W %7 ATToRN YS a m Z l/ 7%? sept. 11, 1956 R. G; FRlEDMAN METHOD FOR FORMING SHELL BLANKS Filed Oct. 10, 1952 INVENTOR. ROBERT G. FP/EDMAN kic-HEY, WAT

United States Patent METHOD FOR FORMING SHELL BLANKS Robert G. Friedman, Tilin, Ohio, assignor to The National Machinery Company, Tifin, Ohio, a corporation of Ohio Application October 10, 1952, Serial No. 314,161

2 Claims. (Cl. 29-13) This invention relates to the manufacture of hollow articles by forging and more particularly to the forging of steel shell cartridge blanks.

With the increased need of large quantities of shell cartridges, it has become desirable to employ high production machines and reduce the cost per unit as much as possible. Many diiculties were encountered because of the close tolerances required and because of the large length of draw necessary. In the past attempts to form the shell cases by forging operations using steel have met With unsatisfactory results since the scrap rate was extremely high, often exceeding 50%.

An object of this invention is to make possible the production of shell blanks from the steel and to reduce the unit cost of the blanks by eliminating large losses due to the high scrap rate previously encountered.

A further object of this invention is to reduce the unit cost by arranging the process so as to reduce the number of anneals necessary during the formation of the blanks.

The process disclosed is advantageous in that the lubrieating coating is applied after several forging operations have taken place, therefore providing a uniform unbroken coating during the latter more ditiicult extruding and drawing operations. In this invention, rod stock material is fed into a rst station of a multiple header. A plurality of dies are mounted on said header and at these dies the stock is cut and formed into a cylindrical pellet by progressive forging operations. In a second phase of the process, the pellet may be heat treated and coated with a lubricant before being automatically fed into a second header wherein a series of forging dies are mounted which progressively form the pellet into the finished shell blank.

The foregoing and other objects and advantages will become apparent in view of the following description taken in conjunction with the drawings, wherein:

Fig. 1 discloses the space relationship of the dies in the first header;

Fig. 2 is a sectional view along 2-2 of Fig. l disclosing the cut-off mechanism and the first station of the forging operation;

Fig. 3 is a sectional view along 3-3 of Fig. 1 showing the structure 'of the three die stations of the first header;

Fig. 4 is a sectiona1 view of the second header showing the arrangement and form of the dies for performing the extruding and drawing operations which take place at the second header;

Fig. 5 is a view along 5 5 of Fig. 4 showing a feed mechanism through which the pellets may be supplied to the second header; and

Fig. 6 is a sectional view showing the shape of the blank formed at each of the sm stations in the two headers and the finished shell case which is formed from the blank.

In the manufacture of a hollow article such as a shell blank according to this invention there are a number of sequental operations which are on the material being formed.

Referring to the drawings, rod stock 10 is fed through a passage 11 iu the cut-off die 12 by any conventional method. Located in axial alignment with the passage 11 is a stock gauge and punch pn 13 which slides axially in the bore 14 of the stock cut-o 16. As the stock i feeds through the cut-off die 12 it projects into the aligned bore 14 and bears against the stock gauge 13 causing the stock gauge to slide axially until it engages a stock gauge stop 17 which is axially adjustable in the stop frame 18. The stock gauge stop may be adjusted axially providing means to adjust the amount of stock to be cut-cif by changing the amount of stock enclosed by the stock cut-cif 16. The stock cut-off 16 then moves to the position shown in phantom n Fig. 2 and in section in Fig. 3, so that the bore 14 is iu axial alignment with the cavity 19 of the die 21. Since the stock gauge and cut-off 13 is mounted in the stock cut-off 16 it also moves to the dotted position shown iu Fig. 2. It is during this movement of the stock cut-off 16 that the portion of the stock protruding into the bore 14 is sheared from the stock 10 and positioned before the cavity 19,

performed progressively thus forming the blank which is forged into a pellet and it the shape of the die cavity 19 as shown at station 1 of Fig. 3. As the header slide 22 returns to the position shown in Fig. 3 the Spring 20 withdraws the punch pn and the cut-off slide moves back to its initial position' and the stock is fed n through the bore 11 into the bore 14 preparatory to the shean'ng of the next blank. A stop 25 is provided to limit the travel of the punch pn due to the force of the Spring 20. The knockout pin 24 also moves axially toward the mouth of the die cavity 19 ejecting the blank from the die cavity and positioning it in a conventional transfer mechanism (not shown) which moves the blank to station 2 where it is positioned in front of the die cavity 26.

During the next cycle of the header slide the'punch 27 upsets the blank in the cavity causing it to conform to the shape of the cavity as shown at station 2 of Fig.

3. It should be noted that the bottom edge 28 of the cavity 26 in the die 29 is rounded so that the blank formed therein will not have sharp corners which may later cause undesirable fins or inclusions in the blank. As the header slide 22 returns to the position shown in Fig. 3 the knockout pin 31 ejects the blank from the cavity 26 and into a transfer mechanism (not shown) which moves the blank to station 3 and into axial alignment with the cavity 32 in the die 33. During this transfer it is preferable to utilize a transfer means which will invert the blank so that the edges of both ends may be rounded.

During the next cycle of the header slide the punch 34 engages the blank and upsets it so that it assumes the shape of the cavity 32 which is the nnal operation in the pellet-forming process. Here again the bottom edge of cavity 32 is rounded and since the blank is inverted both ends now have rounded edges and the pellet has the shape shown at station 3 of Fig. 3. As the header slide again returns to the position shown in Fig. 3, the knockout pn 36 ejects the blank from the cavity 32 into a third transfer mechanism (not shown) which transports the pellet to the next operation.

The pellet may be fed by any conventional means through any desirable heat treatment means to anneal and remove stress which might interfere with later operations. The particular form of the heat treating apparatus or the method of the heat treating itself has not been shown and is'not 'part'of this inventio The pellet may also be coated with a lubricant at this' stage, however, the apparatus for the coating forms no part of this invention. Very desirable results accrue dueto coating thelubricant at this stage instead of the more conventional'method of coating the stock prior to the cut-off since this sequence of coating covers the ends of the cylindrical pellet as well as the sides; It should be noted that the lubricating coating is not damaged by the operations of forming the pellet'since the pellet forging operations are prior to the coating operation.

"From the annealing and coating operations a pellet may be fed" down a chute 41 shown in Fig. 5. The form of the ichute 41 and of the element 42 are not critical to this invention and merely discloses one means of locating the pellet so. that it may be transferred to station 4 on the header 43 and aligned with the cavity 44 of the die 46. Again, any conventional transfer mechanism may be utilized. The transfer mechanism moves the pellet into alignment with the cavity 44 in the die 46 which forms station 4. In the preferred embodiment no upsetting takes place at this station and it is merely used for locatingpurposes. When the header slide 47 moves axially away from, the header bed frame 43 the knockout pin 48 ejects the blank from the cavity 44 into a transfer mechanism (not shown) which axially aligns the pellet with the cavity 49 in the die 51.

As the header slide 47 moves forward the punch 52 engages the pellet and the pellet isextruded outward around the punch and axially along the walls of the cavity 49 thereby forming an intermediate cup-shaped member. When the header slide 47 again recedes from the header 43, the intermediate cup is ejected from the cavity 49 by the ejector pins 50 and a stripper 53 with a bore through which the punch 52 projects during the forward stroke of the? header slide 47 provides means for stripping the intermediate cup member from the punch 52. A transfer mechanism (not shown) moves the intermediate cup member into axial alignment with a bore 54 of a die 56.

As the header slide moves forward again a punch 57 extends into the cavity of the intermediate cup and causes the intermediate cup to be drawn through the die 56 thus performing the rst drawing operation. A second drawing die 58 is formed with a bore 59 axially aligned and adjacent to the bore 54 of the die 56. The same motion of thepunch 57 draws the intermediate cup through the die 56 and also draws the intermediate cup through the die 58 thus performing a double draw n one operation forming the final cup-shaped shell blank. As the header slide 47 again recedes axially from the header 43, the punch 57 also leaves the dies 56 and 58. In this operation, the nal cup-shaped element is held in the bore 61 bythe stripper 60.

When the subsequent cup shapedelement is drawn through the dies 56 and-58 it will engage the prior cupshaped member forcing the prior member to slide up into the bore of the tube 62. During each subsequent cycle of the header slide 47 an additional cup-shaped'mernber is drawn through the dies 56 and 58 thus forcing the cupshaped-members within the tube further up the tube and into any subsequent operation which might be necessary.

High production is achieved with the disclosed method and apparatus for forming the cartridge blanks since a completed blank is formed during each cycle of the header slides. This high speed production method necessarily r method of forming cartridge blanks is ideally suited to conventional bolt forming presses with little or no modification necessary; However, the present method should not be construed to be limited to such forging machinery.

Having completed a detailed description of a preferred embodiment of the present invention so that others skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is not limited by said preferred embodinent but rather is defined in what is claimed.

What is claimed is:

l. That method of making a ferrous metal shell blank Which comprises cutting off a blank of cylindrical stock, upsetting said blank while celd in a cylindrical die having rounded corners at one end face thereof to form rounded corners at one end face of the blank, inverting the blank and further upsetting said blank in a cylindrical l die having rounded corners at one end face thereof to form rounded corners at the other end face of the blank, annealing the upset blank and thereafter coating the entire surface of said annealed upset blank with lubricant, piercing the coated blank with a blunt-nosed punch in a cylindrical die to extrude a portion of the body of the blank along the sides of the die to form an extruded cupshaped blank and thereafter drawing the extruded side; t walls of the cup-shaped blank to provide a shell blank characterized by side walls sequentially extruded and drawn.

2. That method of making a ferrous metal shell blank j which comprises cutting off a cylindrical blank from 4 ferrous rod stock having a diameter less than the diameter of the finished shell blank, upsetting said cut blank in a cylindrical die having rounded corners at one end face of the die to form rounded corners at one end of the formed, annealing the pellet, and thereafter forcing -a punch having a blunt end face of smaller diameter than the diameter of the pellet into the pellet while confined radially for a portion of the axial thickness of the pellet to extrude a portion of the pellet stock around the end face of the punch and form a shallow cup-shaped article and thereafter drawing the side walls of said cup-shaped article through a pair of axially aligned spaced drawing dies of dijferent diameters whereby the extruded side walls only of the blank are drawn to produce a shell blank having an' axial extent substantially twice the axial extent of the cup-shaped article.

References Cited n the le of this patent UNITED STATES PATENTS 2,338,652 Lefere Jan. 4, 1944 5 2,350,491 Butler et al June 6, 1944 2,367,015 Finzel et al. 'Jan. 9, 1945 2,371,716 Snell Mar. 20,'1945