US1387924A

US1387924A - Method of manufacturing shells

Info

Publication number: US1387924A
Application number: US256863A
Authority: US
Inventors: Francis S Denneen
Original assignee: Individual
Current assignee: Individual
Priority date: 1918-10-04
Filing date: 1918-10-04
Publication date: 1921-08-16
Anticipated expiration: 1938-08-16

Description

1 3 7 924 f-1 I, PatentdAllg- 16, 1921.

F.S. DENNEEN.

METHOD OF MANUFACTURING SHELLS. APPLICATION FILED OCT. 4, 191a.

, UNITED STATES FRANCIS S. DENNEEN, OF CLEVELAND, OHIO- METHOD OF MANUFAGTURWG SHELLS.

Specification of Letters Patent.

Application filed October 4, 191a Serial No. 256,868.

To all whomitmay concern: g Be it known that I, FRANCIS S. DENNEEN, a citizen of the United States of America, and a resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented a new and useful Method of Manufacturing. Shells, which invention is fully set forth in the following specification.

This invention relates to the manufacture of shellsor hollow projectiles and, while capable of application to the manufacture of shells for guns of either large or. small caliber, has particular utility in the manufacture of shells for guns of the larger calibers.

luaccordance with the methods now employed in the manufacture of shells to meet the specifications of the U.- S. Government, a cast steel billet is rolled into bars to give the steel the proper physical characteristics, and the bar stock is then nicked and broken into blocks of the proper size. The specifications of certain foreign countries however, permit the use of blocks formed by breaking directly from cast steel ingots the top and bottom of the casting so as to leave clear metal; but such cast blocks do not possess the same physical characteristics as rolled stock. The-block or slug, whether obtained from bar stock or an ingot, is next heated to a forging temperature and placed in the die of a hydraulic press, which press is provided with one or more piercing tools. The piercing tool or tools are forced into the hot metal to provide a central aperture therein, the metal during the piercing operation flowing upwardly in the die around the piercing tool. While the piercing'tool is initially positigned so as to be concentric with the lnner surface of the die, the maintenance of this .concentric relation during the piercing operation depends almost entirely upon the stiffness of the tool and the homogeneity of the hot metal; consequently, it is a common occurrence for the tool to drift during its entrance into the metal, whereby the aperture formed therein is in eccentric relation with respect to the exterior surface of the blank. Furthermore, the length of shell and the thinness of wall that can be obtained by this piercing operation are limited, both because of the frictional resistance opposing a long drawand because of the cooling of the metal where the wall is thin. Therefore, while it is possible to obtain short, relatively thick-walled shells by this piercing operation, it is practically impossible to obtain long, thin-walled shells thereby. "Additionally, the flow of the hot metal under the pressure of the piercing tool qulckly scores the inner surface of the die, and thls effect increases with the length of the draw, sothat, as these diesare relatively expensive, the. cost of maintenance becomes relatively high. y i

Therefore, if arelatively long, thin shell is to be drawn, the blank, after leaving the pierc ng press, is subjected to a further drawing operation in a draw-bench, wherein the heated blank is forced by a hydraulic ram through a series of draw-rings which successlvely decrease in diameter. Such a draw-bench requires the use .of a ram having a stroke of several feet and the power consumed in forcing'the blank through the successive rings is relatively great. Furthermore, the oxidized scale on the blank quickly scores the operative faces of these rings so that here again the cost of maintenance is relatively high. Additionally, a substantial eccentricity between the exterlor and interior surfaces of the blank, which exists in a large percentage of cases, is not corrected by this drawing operation.

While it might be possible theoretically to obtain concentricity between the inner and outer surfaces of the blank from the piercing operation and tomaintain this concentricity during the subsequent operations, the resulting increase in the cost of the forging and drawing operations would be so great. 'as to render it impractical. Therefore, it is customary to form the blank from a'block having a weight of metal greatly in excess.

of that of the finished shell so as to allow for machining off the eccentric portion and the irregular portions which result from the drawing operations. With the larger shells this excess of metal is frequently more than one hundred per cent. of the weight of the finished shell. Furthermore, the removal of such excess metal requires a heavy and costly machine equipment and consumes much time and labor. Additionally, if the eccentricity be so great that it would cost Patented Aug. 16, 1 921.

more to machine it off than to discard the blank, the forging is thrown into thescrap heap. .Therefore, the present method of drawing a shell not only necessitates a large and expensive equipment which consumes a relatively great amount of power and. is

costly in its upkeep, but it is also highly wasteful of the stock.

It has heretofore been proposed to elimimate the use of draw-benches by passing the blank between longitudinally and transversely movable squeezing dies, by rolling the blank, and by hammering the blank between a stationary die and a movable die, but none of these proposed methods, sofar as I am aware, has ever been successful, because none of these methods assures the production of. a concentric shell or the correction of eccentricity already existing in a blank in a way that is both practical and economical.

An object of this invention is to provide a method in the manufacture of shells which eliminates the use of a draw-bench; another object of the invention is to provide a method which enables the piercin operation to be kept, as respects length of raw and thickness of wall, within easy working limits so as'to decrease the wear on the dies and the loss of stock; another object of the invention is to provide a methodwhich. enables the 'use of a smaller blank, with the consequent consumption of less heat and the employment of a lighter piercing equipment; another object of the invention is to pro vide a method whereby any eccentricity arising durin the piercing operation is corrected so t at theblank may be materially reduced in size, the extent of subsequent machining greatly decreased and a substantial saving in stock obtained; another object of the invention is to provide a method which assures a concentric shell 80 that the blank may be kept closer tofinal dimensions, whereby less metal need .be removed, a lighter machine-tool equipment employed, less power, time and labor consumed, tool wear reduced, and'machining to accurate dimensions facilitated; another object of the invention is to provide a method whereby the interior surface of the shell will be left in good condition so that subsequent machining thereof may be reduced or eliminated; another object of the invention is to provide a method whereb eccentric shells heretofore discarded maybe reclaimed; another ob'ect of the invention is to provide a met od whereby a cast ingot may be employed as a blank and the shell still possess the physical characteristics heretofore obtained by the rolling operation. Other objects relate to the provision of a method in the manufacture of shells which is simple, economical and inexpensive to carry1 out, and which eliminates much of the eavy machine equipment heretofore re uired.

, that The invention is capable of being carried out in a variety of ways and by the use of a variety of apparatus. One method of procedure is hereinafter described in detail, and one form of apparatus is diagrammatically illustrated on the drawing. It is to be expressly understood, however, that the example taken is for the purposes ofillustration only and is not to be construed as a definition of the limits of the invention, reference being had to the appended claims for urpose.

Re erring to the drawing, a

Figure 1 represents diagrammatically a blank provided with a mandrel-receiving aperture.

Fig. 2 represents diagrammatically a modified form of blank and one whic is preferred for the reasons hereafter explained.

Fig. 3-represents diagrammatically a blank provided with a beveled pilot-portion coaxial with the axis of the mandrel aperture.

Fig. 4 represents diagrammatically a blank provided with a cylindrical pilotportion coaxial with the axis of the mandrel aperture;

Fig. 5 represents diagrammatically a shell after it has been subjected to the hammering1 action of the simultaneously-acting dies, an

Fig. 6 is a schematic view of an apparatus in which the hammering action may be carried out.

In the performance of this invention a blank 1 is provided with an aperture 2 to receive a mandrel, such blank having the usual boss,3 for receiving a centering recess to be used in the subsequent machining of the shell. This blank may be a cast steel ingot or it may be a block broken from a bar of rolled stock. The mandrel-receiving aperture may be provided by piercing the ingot or block, as heretofore described or, in case a cast ingot is employed, the aperture may be cast in the same by employing a core. If the aperture be formed by mereing a blank, the wall thereof may be left relatively thick as the thinning of the wall will be obtained by the hammering to which the blank is to be subjected; furthermore, as a smaller blank may be used, a lighter piercing press may be employed, less power is consumed thereby, less heat is required by the blank, the labor and discomfort of hendlmg the blank is reduced, the length of draw and loss of stock from eccentricity is d, and the scoring of the die is diminished. While the blanlnmay; be g erally cylindrical, as show 1n Fig. 1, the

' preferred form of blank is one that is tapered to increase in diameter toward its open endasshown at74inFig.2soastoprovide at the latter point an increased amount of stock which supplies metal for the subsequent drawing operation and therefore reduces the extent of displacement of the metal, and which also retains the heat at that portion of the blank which is last subjected to the ering action of the dies.

The blank is then heated, or if it has been obtained by piercing a heated block the blank may be sufiiciently hot so as not to require reheating, and is placed on a mandrel, after which it is subjected to the harm meringaction of simultaneousl acting dies. Any suitable apparatus may employed for this purpose. Referring to Fig. 6 wherein one form of apparatus is shown schemati V cally, the blank 1 is mounted on a mandrel said 21. Any other suitable longitudinally 'tate said shaft a thereto and driven by a belt 9. To move 5 connected to a shaft 6 which may move u r the frame 7. To ropulley 8 is-shown keyed the shaft 6 lotudinally "a sleeve 1% is shown then between co 11 and provided with a rack 12 with which meshes a pinion 13. Said pinion y be driven in any suitable way, either mamacally or uall as by the d wheel 14. The described apparatus for rota and advancing the man. however, is to be taken as typi of any suitable means for rotating and advanc e bl 1'5: spa-ct to dies.

In :1 -05. "t Wll the p it infion, the bl 1 is subjec to e a n action of un which the w:

I i is ported, and snitable apparatus for accemp end m ing suitably bevel a in '2! sho at 16 so as to ply r. 1 and w :1? 1

, min. 19 which pinions 21 driveninsynchronism by the r-.1 which n-rw' nwheelsfitlonthestub w I means,

withreuleously-ac :1. di% I however, ma be employed for operating the dies insyn onism sothatthe'blank shall be subjected to a hammering'actionof simnltancously-acting dies.

The mandrel-and dies may be suitably cooled by water or air-blast and, if found desirable, the blank maybe retained on the elpdwiselmovemlegt in any suite e way, as 'y-apunger arln' g' on the end of the blank under spring or fluid pressure, and receding before the advance of the mandrel in 9. er well understood in the art. Any suitable means or expedient.

to the pulley 8 so that there is substantially no tendency to twist the fibers of the metal as would be the case if the blank were posive y rotated durmg' the eriod of e a ment of the dies therewitli. As the b l a fk gm the dies it is subjected to the ammering action thereof, and said dies, by their I m-u er blows in succession longitudinally and eircerentially of the blank, w or swage the wine m as to reduce its exterior diameter to a predetermined amount and force the metal n: lly of the mandrel to w and '11- the wall of the b to the size. As the sis of the manl and therefore the s I i accident the axis 0 of the dies any w-tricity and the fin- I wwill concentric it:

. By then y m f 1 p outer md is p Hi as to provide a pilot-portion ew :1 with tllfi 0f 1: r1 drel "a r H 1: i x. pilot-portionma he of any le shape, 1-; shown in 3 as a beveled portion 25, and in Fig. 4 as a cylindrical portion 26, shown IS w m' by a "wr portion 25 to the body of the blank, and may be formed during the wvm of the ingot or by mechining the end of the blank'prior to'its introduction into the swaging machine.

With the larger sized blanks, or where the degree of eccentricity is great, so that the hammer blows of the dies may tend to bend the mandrel and its shaft, it may be desirable to maintain the pilot-portion of the blank in coaxial relation with the axis of the mahdrel during the time that the dies are in contact with the blank. This end may be accomplished in any suitable way, as by the provision of a ring27, having an'axial opening thatwill' receive the pilot or finished portionof the-blank, which travels with the blank or permits the same to slip therethrough, such ring preferably being free to rotate withthe blank. If means are provided formaintaining the blank against lat- ,eral'displacement'during the engagement of the hammer dies 15 therewith, the pilot-portion will preferably be made cylindrical, as shown at 26 in Fig. 4, and may be substantially of the same diameter; as the finished blank.

The hammering to which the blank is sub.-

jected, as it is advanced and rotated between the dies 15, changes the physical characteris v cast metal so as to enable the use of cast tics of cast metal so as to make it possible to start with a cast ingot and yet obtain a finished blank having substantially as good physical characteristics as if the blank were made from rolled Furthermore, as the blank is hammered into engagement with and drawnalong the mandrel, the interior surface thereof may be sufliciently smooth so as to require no machining prior to the nosing-inof the shell (except to'cut off the looking lug formed by pressing the metal into a groove in the mandrel when such an expedient is employed). It is therefore within the contemplation of this invention to nosein the shell immediately after the swaging operation and without machining the interior surface thereof, whereby only slight reheating, if any, of the blank is required.

The method heretofore outlined may also be employed in, reclaiming blanks which have been discarded because the eccentricity of the outer surfacewith respect to the inner surface is so great as to render it unprofitable or impossible to machine off the excess metal. In such case, the blank would preferably be provided with a pilot -portion,,

as heretofore explained, and hammered between the simultaneously-acting dies, while hot and supported on a mandrel, to draw and swage the same concentrically with the aperture and to the proper dimensions. In

case the eccentricity renders a portion of the plete the drawing in one heat, it is apparent j that it can be readily withdrawn from the mandrel and reheated, and the drawmg thereupon completed.

It will therefore be perceived that a method of manufacturing shells has been provided which eliminates the use of the draw-bench; which simplifies and cheapens the piercing operation inasmuch as the blank is not drawn into a thin, long wall in the piercing press; which enables the useof a' lighter blank and therefore a lighter piercing press with a consequent smaller consumption of power, heat, time and labor; which insures'the concentric'rty of .the' outer and inner wall atthe end of the drawing operation; which enables the use of a smaller blank whereby there is a correspond ing reduction of subsequent machining with a corresponding saving in macihne equipment, tool wear, and consumption of power, time and labor, which leaves the inner surface of the shell in .good condition so that interior machining may be eliminated and the nosing-in operation follow immediately after the draw; which improves the physical characteristics of ingots without prior rolling;'which eliminates the relatively great waste of stock that has heretofore been unavoidable where the blank had to be progressively drawn and mi ht be eccentric with respect to its inner wa ;and which is simple, relatively inexpensive and economical. Furthermore, a process has been provided which not only eliminates the wasting of blanks because of undue eccentricity, but-provides for the reclaiming of such blanks as have heretofore scribed, it is to be expressly understood that this apparatus has been selected for purposes of illustration only, as the invention may be practised with a wide variety of apparatus as will be readily appreciated by those skilled in the art. Therefore reference is to be had to the claims hereto a pended for a definition of the limits of t e invention.

What is claimed is:

1. In the manufacture of shells, providing a blank with an aperture to receive a mandrel, shaping the end of said blank to provide a pilot-portion substantially coaxial with the axis of the mandrel aperture, and

hammering. said blank while hot and supported on a mandrel between opposed simultaneously acting dies the acting faces of which are coaxial with said mandrel.

2. In the manufacture of shells, providing a blank with a mandrel receiving aperture and an annular wall increasing in thickness toward the apertured end of said blank, shaping the opposite end of said blank to provide a pilot portion substantially CO7 axial with the axis of the mandrel aperture and hammering the blank while hot and supported on a mandrel between simultaneously acting dies the acting faces of which are coaxial with said mandrel.

3. In the manufacture of shells, providing a blank with'a mandrel receiving aperture and an annular wall increasing in thickness toward the apertured end of said blank, shaping the opposite end of the blank to provide a pilot portion coaxial with the axis of the mandrel aperture, rotating and advancing said blank while'hot and supported on a mandrel between simultaneously acting dies the acting faces of which are coaxial with the axis of said mandrel, and hammering said blank with said dies to elongate and thin the walls of the same.

4. The process of reclaiming eccentric shells which comprises rendering the exterior surface of the shell concentric with I the interior surface thereof by hammering the shell while hot and supported on a man drel between simultaneously acting dies the acting bases of which are coaxial with said mandrel.

5. In the manufacture of shells, providing a blank with an aperture to receive a mandrel, and elongating and thinning the wall of said blank by hammering the same while hot and supported on a mandrel betweensynchronously-actuated dies movable toward and from an axis coincident with the axis of said mandrel.

6. In the manufacture of shells, piercing a blank to provide a mandrel-receiving aperture, and swaging said blank to elongate and thin the wall of the same while rendering the exterior surface thereof concentric with the axis of said aperture by hammering said blank while hot and supported on a mandrel getween opposed simultaneously-actuated a blank with a mandrel-receiving aperture; providing said blank with a cyllndrical pilot-portion concentric with the axis of said mandrel-aperture, and hammering said blank while hot and supported on a mandrel between simultaneously-acting dies.

9. The process of reclaiming eccentric shells which comprises shaping the end of said shell to provide a pilot -portion substantially co-axial with the axis of the interior wall of said shell, and hammering said shell while hot and supported on a mandrel between simultaneously-acting dies having the axis of their active faces coincident with the axis of said mandrel.

10. In the manufacture of shells, providing a blank with an aperture to receive a mandrel, rotating and advancing said blank while hot and supported on a mandrel between simultaneously actuated dies, and hammering said blank with said dies to elongate and thin the wall of the same.

11. In themanufacture of shells, providing a blank with an aperture to receive a mandrel, shaping the end of said blank to provide a pilot-portion substantially coaxial with said mandrel aperture, rotating and advancing said blank while hot and supported on a mandrel between synchronously-operating dies having their acting faces coaxial with said mandrel, and hammering said blank with said dies to elongate and thin the wall of the same.

12. In the manufacture of shells, providbetween simultaneously-acting dies the acting faces of which are co-axial with said mandrel, and hammering said blank with said dies to render its exterior surface concentric with its interior surface while elongating and thinnin the same.

14. In the manu acture of shells, providing a blankwith a mandrel-receiving aperture and an annular wall increasing in thickness toward the apertured end of said blank, and elongating and thinning said blank by hammering the same while hot and supported on a mandrel between simultaneouslyacting dies having their acting faces coaxial with said mandrel.

In testimony whereof I have signed this specification.