US2335916A - Method of flanging sheet metal can bodies - Google Patents

Description

Dec. 7, 1943. J. coYLE' ,METHOD OF FLANGING SHEET METAL CAN BODIES Filed May 7, 1942 Patented Dec. 7, 1943 METHOD OF FLANGING SHEET METAL CAN BODIES John Coyle, Baltimore, Md., assignor to Continental Can Company, Inc., New York, N. Y., la corporation of New York Application May 7, 1942, Serial No. 442,072

- 2 Claims.

The invention relates to new and useful improvements in a method of anging sheet metal can bodies, having a side seam with solder-bonded lap sections at the ends thereof.

One of the usual methods of hanging can bodies, consists in subjecting the formed can body to a Hanging die which is shaped so as to expand and roll the edge portion of the can body outwardly into a flange which lies in a plane substantially at right angles to the longitudinal axis of the can body. This produces a curved section in thercan body which joins the flange to the body portion of the can. The radius of this curvature is substantially uniform throughout the circumference of the can body except in the region of the side seam where the walls of the can body are lapped and solder-bonded together. During flanging these solder-bondedv sections resist the flanging die so that the curvature is often on a greater radius, and this interferes with the forming of a tight seam all the way around the can body when an end is secured thereto. When the body is die-shaped from cylindrical form into a flanged end after solder-bonding, the solder is strained at the side seam due to the expansion of the metal to form the flange, and this straining of the solder-bond sometimes causes the body wall which merges into the flange in the region of the lap sections is curved substantially on the same radius as the body wall in other regions.

A further object of the invention is to provide a method of hanging a can body, wherein the curvature of the body wall which merges into the ange in theregion of the lap sections is preformed to a large extent before the solder-bonding takes place, so as to reduce the strain on the solder-bond during die shaping of the body wall in the final flanging operation.

A still further object of the invention is to provide a method of fianging can bodies wherein the body Wall in the region adjacent the section from which the flange is to be formed and in the region of the lap sections is curved inwardly so as to reinforce and stiffen the portion of the can body through the side seam from one side of the can body to the other.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawing which shows a can body of the lock and lap seam type anged by my improved method,

Figure 1 is a View showing a portion of a can body having the hooks interlocked preparatory to bumping the side seam.

Fig. 2 is a View similar to Fig. 1 after the joined edges have been bumped preparatory to solderbonding the same.

Fig. 3 is a sectional view on the line 3 3 of Fig. 2 and showing in broken lines the formed flange.

' Fig. 4 is a sectional View on an enlarged scale through the Spline and the hammer showing the seam in its nal bumped condition.

Fig. 5 is a view showing more or less diagrammatically a portion of thedie for forming the flange partially entered into the can body preparatory to the flanging operation. Y

Fig. 6 is a View similar to Fig. 5 but sho-wing the flanging operation as completed.

Fig. '7 is a diagrammatic view showing the reinforcing rib extending across the body wall in the region of the side seam, Vthe view beingV taken substantially on the line 1-1 of Fig. 2.

The method will be described as applied to the ange of a can body having a lock and lap side seam. This type of can body is well known and only brief reference is necessary to the features of construction.

The can body section l is joined to the can body section 2 by a side seam which includes hooks which are engaged with each other. These hooks terminate short of the ends of the can body so that there are lap sections only in the region where the flange is to be formed. As viewed in Fig. 1, the can body is seen from the'outside of the body and the outer lap is shown at 4 in full lines, while the inner lap is shown at 5 in broken lines.

The can body is formed in cylindrical shap about a horn and the hooks are interlocked after which they are bumped to bring them into very tight and intimate contact with each other. This is accomplished by a bumping iron or hammer which is brought into contact with the outer face of the can body in the region of the interlocked hooks. The seam is bumped against the spline which is located in the horn. In Fig. 4 of the drawing a portion of the spline 6 and the bumping iron o'r hammer l are shown. In carrying out my improved method the spline is provided Wth a recess 8 which extends across the spline from one side thereof to the other. The bumping iron or hammer is provided with a curved `rib 8 which is opposed to the recess 8.

When the seam is bumped the body wall in the region of the hooks and the lapped sections adjacent the hooks will be curved inwardly, thus forming a rib on the inner wall of the can body which extends across the side seam and into the can body wall adjacent the side seam. This rib reinforces the body wall and greatly strengthens the same so as to prevent any hinge-like action on the seam formation which is likely to Open the seam.

The spline 6 is also provided with a recess I which is curved on a radius conforming substantially with the curvature of the body wall merging into the flange after the Vhanging operation. This curving of the body wall is limited substantially to the region of the lap sections. The hammer 'I is provided with a rib II which is curved to conform to the curvature in the recess, and during the bumping operation the lap portions of the side seam are curved inwardly as indicated in Fig. 4 of the drawing.

The bridging member formed during the bumping operation through the cooperation of the rib 9 on the hammer and the groove 8 in the spline is indicated at I2 in the drawings. This rib is substantially straight and is in a sense a chord to the curvature of the cylindrical body. As shown in Figs. 2 and 7 the bridging rib extends through the side seam from one side of the can body to the other side. This rib is formed before the can body is solder-bonded. The solder-bonding of the seam is not shown in the drawing, as it is likely to confuse the same, but it is understood that when the sfide seam is solder-bonded, the solder will how into the side seam throughout the limits thereof and join the contacting metal parts together.

During this bumping operation the rib II on the hammer cooperating with the recess I0 formed a curved portion I3 in the region of the lap sections, which curved portion is shaped so that it conforms substantially to the curved portion I4 which joins the finished harige I5 to the body wall. This curved portion I3 extends from a point I6 to a point II. I'I to the end of the can body the body wall is expanded into the harige. The hanging die used for forming the flange on the can body is indicated at I8. This hanging die has a portion I8a extending down into the can body below the rib I2 and is of such shape as not to deform this rib. It also has a portion |81) which is dimensioned so as to contact with the inner surface of the bead I3. 'I'he curvature of the bead I3 from the point IB to the point II is closely approximated to the curvature of the hanging die from the point I8c to the point I8d, see Figs. and 6. When the die therefore is forced down into the can body the upper end of the can body will be expanded and forced outwardly to form the harige. The beaded portion I3 will swing about the point I6 more or less as a hinge, for the reason that the curvature of the portion I3 approximates the curvature of the die which contacts therewith as the die moves on down for the hanging operation. In other words, this portion of the can body in the region of the lap sections has a preformed curve similar to the curve which joins the flange to the body wall, and it is moved outwardly during this hanging operation. As stated above, the hanging die when inserted into the can body expands the end of the can body into a flange and at the same time it positions the preformed curved portion in the lap section so that it merges From the point r into the hange on substantially the same curvature as other portions of the body wall. This shaping of the body wall took place before the solder-bonding of the lap sections, and this preforming or curving of the body wall in the region of the solder-bonded lap sections greatly facilitates the expanding and shaping of the can body to form the harige without undue strain on the solder-bond.

It is well known that the grain of the metal forming the can body which is curved around a horn, extends in the general direction of the curvature of the body, and that it is parallel with the end edges of the can body. However, when this section of the side seam is bumped so as to provide the curved portion I3 the grain in the curved portion will be changed so that it extends lengthwise of the seam and therefore A the shifting of this curved portion I3 and whatever reshaping is necessary to provide the flange is aided by this change in the grain of the metal.

From the above it will be apparent that three things have been accomplished in my improved method of hanging, al1 of which cooperate to the reducing of the strain in the solder-bond during hanging and the forming of a flange wherein the curved portion of the body wall merging into the flange is of a substantially uniform radius in the region of the side seam, as well as at other points in the circumference of the can. One of the features is the pre-shaping of the metal in the lap sections prior to solder-bonding so as to facilitate the curving of the body wall in this region during hanging without undue straining on the solder-bond. Another feature is the precurving of this section of the seam prior to solder-bonding so as to facilitate the forming of the flange so as to have a uniform curvature throughout to aid in the seaming of the end of the body in a very tight uniform seam. The third feature is the forming of the reinforcing rib where the lap sections join the hook sections of the seam. This reinforcing rib extends across the seam transversely thereof and extends into the body wall from oneside of the can body to the other. This reinforcing rib stiffens Athe can body so as to prevent the seam from opening up by the hinging action of one of the hook sections on the other and the rupturing of the solder-bond. This not only aids in the'preventing of the rupturing of the solder-bond during packaging, but it also prevents rupturing of the solder-bond during storage of hanged can bodies prior to the seaming of an end thereon. While a reinforcing rib is shown located at the junction of the hooks and the lap sections of the seam, it is understood that reinforcing ribs may be placed at other points along the side seam.

While the method has been described as ap,- plied to a can body of the type wherein the side seam has interlocked hooks and lap portions at the ends thereof, it is to be understood that my improved method of hanging may be equally applied to a side seam wherein the edge portions are lapped throughout the entire length of the side seam.

I claim:

1. The method of hanging sheet metal can bodies having a side seam with solder-bonded lap sections at the ends thereof, consisting in bumping the lap sections of the side seam on a line parallel to the edge of the body and in the region where the lap sections are to be expanded and curved outwardly so as to merge into a flange, for curving said lap sections inwardly ona line of curvature conforming substantially to the curvature of the body wall merging into the ange after anging, solder-bonding the side seam, and subjecting said can body to a flanging die for expanding the end of the can body into a flange and positioning said preformed curved portion in the lap section so that it merges into the flange on substantially the same curvature as other portions of the body wall.

2. The method of flanging sheet metal can bodies having a side seam with solder-bonded interlockedhooks and lap sections at the ends thereof, consisting in bumping the lap sections of the side seam on a line parallel to the edge of the body and in the region where the lap sections are to be expanded and curved outwardly so as to merge into a flange, for curving said lap sections inwardly on a, line of curvature conforming substantially to the curvature of the body wall merging into the flange after anging, also bumping the side seam in the regions where the ends of the hooks terminate for curving the same inwardly to form a reinforcing rib extending across the side seam from one side of the body to the other, solder-bonding the side seam and subjecting the can body to a Hanging die for expanding the end of the can body into a flange andrpositioning said preformed curved portion in the lap section so that it merges into the flange on substantially the same curvature as other portions of the body wall.

JOHN COYLE.

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