US1389739A - Method of forming a pressed metal article - Google Patents

Description

H. G. CARLSON. METHOD OF FORMING A PRESSED METAL ARTI CLE. APPLICATION FILED SEPT. 17, 1918.

1,889,739. Patentedsept. 6, 1921.

H. G. CARLSON. METHOD OF FORMING A PRESSED METAL ARTICLE.

APPLICATION FILED SEPT. 17, 1918. 1,389,739.

Patented Sept. 6, 1921.

- UNITED STATES PATENT OFFICE.

HJALMAR G. CABLSO'N, OF WORCESTER, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ROCKWOOD SPRINKLER COMPANY OF MASSACHUSETTS, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

METHOD OF FORMING A PRESSED METAL ARTICLE.

Specification of Letters Patent.

Patented Sept. 6, 1921.

Application filed September 17, 1918. I Serial No. 254,481.

To all whom it may concern:

Be it known thatI, HJALMAR specification.

This invention relates to a method of pro- :ducing from a flat sheet metal blank a tubular article having one end of materially thicker stock than the other, but integral with the tubular portion. Such an article can be formed for any desired purpose.

The invention involves. the process of gradually producing such an article by a series of cold'drawlng operations and doubling over its end in dies so as to render the end portion of more than double thickness as described. Further objects and advantages of the invention will appear hereinafter. 1

Reference is to be had to the accompanying drawings, in which-- Figure 1 is an edge view of a circular blank of soft sheet metal from which the article is to be produced, and

Figs. 2 to 12 .inclusive are. longitudinal central sectional views of the blank in several stages of its roduction, the order of the steps being in icated by the numerals designating the several figures, Fig. 12 showing'thei completed article so far as the metal drawing operations are concerned.

The invention is shown herein as being employed for the prqiuction of a combination booster casing and adapter for a shell, the adapter being integral with the booster casing'and being formed with a doubled over external flange as indicated above. This is a cold drawn article, but of course the metal is annealed as many times as may be necessary. The article, of course,.can be made in any desired size or shape, but the oneillustrated is made from a circular blank 10 0f annealed sheet stock as indicated in Fig. 1. This is shaped by dies to produce by the first operationa flanged cup such as indicated in Fi 2. By this operation the center of the b ank is drawn out to forma central cup-shaped portion 12 having a circumferential flat edge 11 at the open end The.

GfCAnLsoN, a citizen of the United States, residing at.

diameter of the blank is reduced by this operation and the metal is only slightly thickened at the edge.

The second operation, the result of which isindicated in Fig. 3 is shown mainly for the purpose of flattening and thinning the base 13 of the blank. The thinning however may be omitted in some classes of work. The internal and external diameters of the walls between the base and edge flange 11 are reduced by this operation and the length of the cylinder increased. The thickness of the flange 11 is unchanged although as this Iflange is not'held between flat surfaces, it

becomes curved.

The third operation changes the shape of the blank shown in Fig. 3 to that shown in Fig. 4:, in which the edge flange 11 is not materially increased in area. The internal and external diameters of the tubular portion are materially reduced,the thickness of the stock everywhere remaining substaki tially the same.

By the next operation indicated in Fig 5 again the only change produced is the reduction in diameter of the cylindrical portion of the blank and lengthening it.

The next operation also is for a similar purpose, the diameter being reduced slightly and the length increased. This result is indicated in Fig. 6.

It will be seen that Figs. 4, 5 and 6 represent the results of three operations, each of which has for its object merely the reduction in diameter and the increase in length of the cylindrical portion of the blank. No change in thickness is intended anywhere, but it is found that the diameter of the flange 11 may be increased slightly, and of course its width is materially increased. 2

The next operation, the result of which is shown in Fig. 7 also involves the lengthening of the tubular portion, but by the reduction of its end only. The open end 141 of the tube near the flange 11 is left in the same condition as in Fig. 6, but the closed end is drawn out between the die and the flange 11 has a wavy shape, a circular corrugation being formed in it. This is provided to store a surplus of metal here so that in performing the next operation shown in Fig. 9 there will be stock to force into the square corners of the dies and fill them up to produce the shoulder 17. The edge is now trimmed off to a true cylindrical surface to exactly fit the dies shown in Fig.8 and hold the metal so that the square shoulder can be formed by means of these dies. The flange 11 is flattened out, or its flattening completed, between the flat die plates. When the cup leaves the dies shown in Fig. 8 its shoulder 15 is nearly square and its flange is flat. Preferably a corrugation 18 is then formed in the edge of the flange to produce the shape shown in Fig. 9.

Having brought the blank tothis form, the thin tubular portion 16 is in its final shape as is also the thickened portion 14 at the base. The flange 11 is the only thing that now remains to be shaped, and this is bent over by forcing it through a die and assumes the form shown in Fig. 10. It now constitutes an external rim 11 of circular shape spaced from the inner wall 14.

Two operations in forming dies force this rim 11 up against the surface of the wall 14. The results of these operations are shown in Figs. 11 and 12. Fig. 11 shows the rim drawn in and Fig. 12 shows it upset against the wall 14. In the final condition this rim 11 constitutes an integral external wall of conical shape connected with the internal wall 14 at the end, which in turn is integral with the tubular casing 16 below. It is to be observed that the upsetting causes both walls 11 and 14 to be materially thicker than the wall 16. I have shown the rim 11 as extending beyond the shoulder 15 which connects the tubular casing 16 with the inner wall 14.

A feature shown in Fig. 12 is the anchoring of the rim 11 to the wall 14 on the out side. As the rim 11 is upset longitudinally and is forced in over the shoulder 17, its inner surface assumes a barrel shape and gives the wall 14a corresponding form fitting in it. This anchors the two'parts together. Thus, if any weakness develops where the rim is bent over, it tends to be compensated for by this construction. WVhen it desired to still further strengthen this part of the article the corrugation 18 is pro vided. This furnishes surplus metal for forming a solid projection 19 which is drawn in behind the shoulder 17 and absolutely prevents the fracture of the article where the rim is turned over. It also makes the rim 11 very thick and rigid so that it will stand threading without being unduly weakened.

The external conical surface of the rim 11 is to be provided with a pipe thread if the device is to be used as an adapter. The inner wall also is to be provided with an internal screw-thread for receiving an internal element whenever that is desired. The part of the rim at the end beyond the screw thread is shown as octagonal in form so that it may be screwed in by a wrench as usual. This is formed in the last operation.

It will be seen, therefore, that by a series of operations such as described above, a flat blank of sheet stock can be converted into a tubular structure having comparatively thin end and side walls and provided with a'base having walls of double thickness, each of the latter walls being of greater thickness than the original blank, and that this furnishes a solid and firm base integrally connected with the tubular casing which it supports. Such an article can be used as a combined adapter and booster casing in a shell, but the process can be used for manufacturing articles of other various kinds requiring similar properties.

I am aware, of course, that the exact number of steps set forth herein is not absolutely essential to all kinds of articles that can be made by this process; for example, the three steps represented by Figs. 4, 5 and 6 can be replaced by two or four steps if the particular conditions require it, and the same is true of the operations represented by Figs. 7, 8 and 9. Moreover in making adapters for other shells modifications within the skill of any person skilled in the art may be made in this process without departing from the scope of the invention as expressed in the claims. Therefore, I do not wish to be limited in these respects, but what I do claim 1S 1. The method of making an article having a hollow closed end and a'double-walled open end, which consists in drawing out a flat blank of cold drawn sheet stock into an elongated tubular shape with one end closed and reduced in thickness and the other end having a circular flange surrounding it, then reducing and elongating the closed end only of the blank by a series of steps, and finally turning over the flange so as to envelop the adjacent wall of the blank.

2. The method of making an adapter and booster casing whichconsists in drawing out a flat blank of sheet stock intoan elongated tubular shape with one end closed and the other end having a circular flange surrounding it, then reducing and elongating the closed end of the blank by a series of drawing operations, leaving the open end of that part of the blank unreduced in diameter and thickness, and turning over the flange into contact with the adjacent convex wall of the blank beyond the unreduced portion to hold the two parts together.

3. The method of drawing sheet metal stock which consists in drawing out a projection from a blank, leaving the open edge in the form of a surrounding flange, forming a shoulder on the projection, doubling over the flat flange to form a rim surrounding the open end of said projection, and finally forcing the rim against the wall which constitutes theend of the projection and behind said shoulder.

4. The method of cold drawing sheet metal which consists in drawing out a tubular projection from a flat circular blank, leaving the open edge in. the form of a surrounding flange, annealing it at suitable intervals, elongating and reducing in diameter the tubular pro ection, thereafter maintaining the portion of this tubular projection near the open end in substantially uniform condition, and while in that condition drawing out the closed end of the same so as to increase its length and reduce its diameter and thickness, forming a shoulder at the end of the thicker portion of the same, doubling1 over the flange so as to form a rim surrounding the thick portion and projecting beyond said shoulder, and finall forcing the same against the inner wall to ring the rim at its edge beyond the shoulder, u setting the rim and giving it a conical s ape outside.

5. The method of drawing sheet metal stock which consists in drawing out in dies a central projection from a flat circular blank, leaving the open edge in the form of a surrounding flange, progressively drawing out the closed end so as to increase its len th and reduce its diameter and thickness at t e end, forming a shoulder on the thicker portion of the same, doubling over the flat flange, and finally forcing the same against the inner relatively thin wall which constitutes the end of the tubular part and over said shoulder.

6. The method of drawing sheet metal which consists in drawing out in dies a central projection from a flat circular blank so as to leave the open edge in the form of a surrounding flange, forming a circumferential shoulder on the projection, doubling over the flange, and finally forcing the same toward the inner wall to bring the external wall or flange at its edge beyond the shoulder, and upsetting the projecting edge against said shoulder.

7. The method of cold drawing sheet stock which consists in drawing out in dies a central projection from a flat circular blank so .as to leave the open edge in the form of a surrounding flange, progressively elongating and reducing in diameter the central portion thereof to form a tubular shape, maintain ing the portion of this tubular part near the open end in substantially uniform condition, while in that condition progressively drawing out the closed end of the same so as to increase its lengthand reduce its diameter, forming a shoulder on the thicker portion of the same, doubling over the flange, and finally forcing the same against the thick wall, forcing its end over said shoulder and upsetting it lon itudinall to give the inner surface of the ange an the outer surface of the thick wall an interlocking convex or barrel shape.

In testimony whereof I have hereunto aflixed my si nature.

DHJALMAR G. CARLSON.

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