US2341667A - Means for drawing shells - Google Patents

Description

Feb. 15, 1944. T, F. STACY 2,341,667

MEANS FOR DRAWING SHELLS Filed May 20, 1942 2 Sheets-Sheet 1- 7 A5- k m MENTOR;

Feb. 15, 1944. T. F. STACY MEANS FOR DRAWING SHELLS 2 Shets-Sheet 2 Filed May 20, 1942 v /N VEN fa? Patented Feb. 15, 1944 FFlCE MEANS FOR DRAWING SHELLS Thomas F. Stacy, Piqua, Ohio, assignor to The French Oil Mill Machinery Company, Piqua,

Application May 20, 1942, Serial narrates 2 Claims.

This invention relates to the production of metal, cartridge shells and analogous shells or cases, and particularly to improvements in a punch and die method and means for'redrawing partially drawn or formed shells or cases. In the production of artillery cartridge shells, according to the present practice, the shell is formed by successive punch and die drawing operations. A'flat metal disk or blank of appropriate alloy or characteristics is first pressed or drawn, by means of a punch and die, into the form of a cup or shell having a relatively short cylindrical wall. This cup is then elongated or increased in length until the final required length is reached by successive redrawing operations, each performed in a separate press or machine byv an appropriately formed drawing die and punch. 1

Referring, by way of specific example, to the method used at the present time to manufacture 75 um. cartridge shells, the disk of cartridge brass is drawn in the first operation, into the form of a cup, the length of which is approximately 3". Then, in the first redrawing operation, this cup is drawn or lengthened to a shell of approximately 5%" in length. By a second redrawing operation,

this shell is drawn out or lengthened to approx imately 9". These redrawing operations are repeated until the final length of the shell, approximately is obtained. Theblank-cupping and first redrawing operations can be performed in mechanical presses, but according to'the present practice, the second and succeeding redrawing operations are performed inhydraulic presses in each of which the shell produced by the preceding redraw is placed with its open end upwardly in a die on the stationary bed of the press,

and the punch, which is mounted on the lower end of the movable press ram, is moved downwardly into the shell. By continued downward movement of the punch after its end engages the base of the shell, the punch pushes the shell through the drawing die, and thereby increases the length and reduces the thickness of the cylindrical wall of the shell. The second and succeeding redrawing operations are performed similarly in successive hydraulic presses. With such organization of the press, the punch, in its retracted or raised position has to be spaced upwardly from the die a distance greater than thelength of the shell to be redrawn, to give sumcient space or clearance to enable the shell to be conveniently placed in position in the die beneath the punch. Therefore, in the redrawing operation of the press, the punch has strength of the finished shell.

distance greater than the length or the shell before it engages the base of the shell and starts the redrawing movement of the shell by'forcing it through the die. This means a lost or waste motion of the press ram in the drawing operation, of a length, at least, as long as the peripheral wall of the shell. In each redrawing operation, the speed of movement of the punch is restricted to a more or less well defined maximum in order to insure the required perfection and For instance, a practical punch speed for the second redrawing operation in the example cited is approximately 4'0 per minute, or about 8" per second, so that in this redrawing operation, assuming the shell being operated upon to be aproximately 5 long, there'is a loss of approximately one second of time for the punch to cover the lost motion or waste distance before it engages the base of the shell. The lost motion and lost time greatly increase with each succeeding redrawing operation, since in each, the shell is longer and the speed of travel of the punch is slower, and thus materially curtails the speed of production of the shells.

A primary object of my invention is to provide an improved method and means whereby such lost motion and loss of time in the drawing operation is prevented, so that the speed of production of the shells is very materially increased without increasing the speed of travel of the ram or movable press element.

Other objects of the invention are to provide a drawing press or machine for cartridge and analogous shells in which thepunch is held stationary during the drawing operation while the die is carried by the movable press ram or element, in an arrangement whereby the length of stroke of the latter is greatly shortened; also to provide a drawing press or machine in which the die is carried by the movable press ram and moves axially towards and from a punch which is held relatively stationary but which, however, is movable into operative position transversely from a position at one side of the path of movement of the die, so that the shell can be quickly and easily placed on the punch and carried by the punch tothe drawing position in alinement with the die;

' in which the die and punch are arranged and to move downwardly into the shell for a related in such a way that the shell tobe drawn can be placed on the punch while it is at one side of its operative position, and moved with the punch into operative alinement with the die for drawing the shell by relative axial movement between the die and punch; and in which the drawing die is carried by the movable press ram and 2 v a plurality of punches are arranged on a turret or punch carrier, which is movable in a direction of the preferred embodiment of the invention,

shown in the accompanying drawings, and the novel features of the invention are set forth in the appended claims.

In said drawings:

Fig.) is a fragmentary side elevation, on a reduced scale, of a drawing pressillustrating one embodiment of my invention.

Fig. 2 is a sectional plan view 2-2, Fig. 1.

Fig. 3 is a side elevation, on a larger scale, of the die holder and one punch, showing the drawn shell in the die holder after it has been stripped from the punch.

Fig. 4 is a fragmentary, sectional elevation showing the die holder, punch turret and punches with one punch carrying a shell in position for drawing cooperation with the die.

Fig. 5 is a sectional elevation of the die holder and one punch showing the position of the parts after the punch has forced the shell through the die, and before retracting the die to strip the shell from the punch. V

The invention is not restricted to the construction of the press, and the latter may he oi any suitable construction, comprising a bed or support, which is preferably stationary. for the punch turret or carrier, a ram or element which carries the drawing die, and means for effecting a relative axial movement between the punch carrier and die carrier to cause the punch to force the shell through the drawing die.

thereof on line In the embodiment of the invention illustrated in the drawings, the press comprises a stationary bed or base lllabove which, and suitably connected in fixed relation to the bed, is a cylinder i l in which a ram I2 is movable vertically toward and from the base. Suitably secured to the lower end of the ram, as for instance by side bolts I3, is a die holder II in the lower end of which is mounted a drawing die l5. This die maybe of usual or any suitable construction and suitably secured in the die holder. As shown, the die holder is provided above orbeyond the die ll with the usual stripping plates or devices lid for engaging the lower end of the shell after it has been drawn by passage through the die, for stripping the shell from the punch when the die is retracted or moved away from the punch.

Preferably, a plurality of punches ii are mounted on a turret or punch carrier I I which is movably supported on the bed or base of the press so that by movement of the punch carrier horizontally, or in a direction transverse to the axial line of movement of the die, the punches can be moved successively into and out of drawing position beneath the die in axial alinement therewith. As shown, four punches ii are provided, and are suitably fixed at equally spaced distances circumferentially on a circular turret annularretainingriug llisshowmsecuredon the bed and overlying the peripheral edge of the turret, to prevent movement of the turret upwardly or awayfrom the bed.

with the press thus constructed, the shells to be redrawn can be quickly and easily placed on or slipped over the upper ends of the punches with the bases of theshells engaging'the tops of the punches 'while the latter are at one side of, or out of the path of movement of, the die holder. Then, by turning the turret, a punch. with the shell thereon, is placed beneath the die in axial alinement therewith, ready for drawing the shell by downward movement of the ram and die.

The die, in its retracted, or uppermost position need only be spaced far enough above the'turret to give a sumcient clearance between the lowermost part of the die holder and the shells on the punches to insure proper movement of each shell into drawing position beneath the die by rotation of the turret, without danger of engagement with the die holder. Therefore, the lost motion or inactive movement of the ram and die is confined or reduced to a travel only equal to the short length of the space or clearance between the die and the base of the inverted shell on the punch beneath the die. The drawing action on the shell starts as soon a'sthe die moves this short clear-' ance distance and contacts the shell, and it is not necessary, as has been the case in previous presses in which the shell is placed base-down ward in a stationary die, for the punch to move down into the shell for the full length of its cylindrical wall before the end of the punch engages the base of the shell. The lost motion or insctive travel of the ram and die is therefore shortthe cylindrical wall of the shell.

In the downward movement of the ram-and die,

the shell is forced by the punch upwardly through the-die into the die holder, and during the retraction or upward movement of the ram, the stripping devices will operate in the usual manner to engage the lower end oi the shell and strip'it from the punch. The redrawn shell is thus left in the die holder when the latter has been retracted, and the shell can be quickly and easily ejected from the holder by pushing it out through an opening 20 in the side of the die holder. For this purpose, in the construction shown, two such side openings 2. are provided in the die holder at opposite sides thereof, so that the shell can be ejected through one side opening by pushing it with the finger or an implement insorted into the openingat the oppositeside of the holder. 1

It will be understood that various changes in the details and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art withinthe principle and scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. In a press for drawing cartridge shells and the like, comprising a drawing die, and a punch for forcing a shell through the die, the improvement which comprises a stationary support, a ram arranged opposite said support. adie holder in which the die is mounted and which issecured on the ram, means for moving said ram toward and from said support, and a punch stationarily supported by said support in axial alinement with said die, whereby a shell to be drawn which is placed on said punch when the die is retracted, is

forced by said punch through said die by move t ment 01' the ram toward said support, and means in the end portion of said die holder nearest to the punch but beyond the die for stripping the shell from the punch and retaining the shell in the die holder when the ram and die are moved away from the punch, and said die holder having an opening in one side thereof through which the drawn shell can be ejected from the die holder.

2. In 'a press for drawing cartridge shells and the like, comprising a drawing die, and a punch for forcing a shell through the die, the improvement which comprises a stationary support, a turret on which the punch is secured and which is mounted to rotate horizontally on said support for carrying the punch to and from a position vertically beneath the die, a ram which is mounted above said support to move vertically toward and from said turret, a die holder in which the die is mounted and which is secured to said ram, means for moving the ram toward and from the turret, whereby a shell to be drawn is adapted to be placed on the punch when the ram is retracted and the punch is out of the line of movement of said die holder, and to be moved into alignment with the die by turning said turret, and said shell is forced through said die by movement of the ram toward said turret, stripping means in the lower end portion of said die holder abovethe die for stripping the drawn shell from the punch and retaining the shell in the die holder when the ram is retracted, and said die holder having a side opening through which a drawn shell can be ejected from the die holder.

THOMAS F. STACY.

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