US2791349A - Metal container and process for its manufacture - Google Patents

Description

May 7, 1957 v R. MbRAND' 2,791,349

METAL CONTAINER AND PROCESSWFOR ms MANUFACTURE w Filed June 24. 1954 I5 Sheets-Sheet 1 g INVE-N TOR ROBERT MORA ND 7 May 7, 1957 R. MORAND 2,791,349

' METAL. CONTAINER AND PROCESS FOR ITS MANUFACTURE I 3 Sheets-Sheet 2 Filed Jung 24. 1954 "pl-1'11 I INVEINIOR ROBERT MORAND May 7, 1957' METAL CONTAINER AND PROCESS FOR ITS MANUFACTURE Filed June 241954 R. MORAND 5'Sheets-Sheet 5 INVENTOR ROBERT MORAND BY VJ/#141,411

United States Patent lVlETAL CONTAINER AND PROCESS FOR ITS MANUFACTURE Robert Morand, Beaurepaire, France, assignor to Exlam Societe Anonyme, Tangier, a corporation of the International Zone of Tangier Application June 24, B54, Serial No. 438,971 Claims priority, application Switzerland June 29, 1953 1 Claim. (Cl. 220-54) This invention relates to a seamless metal container having a top which is hermetically attached to the shell of the container and which is removable by means of a novel arrangement.

Containers having the same purpose as that of the present invention have, for instance, been described in U. S. Patents Nos. 1,615,930 and 1,764,883. In these containers, a blank stamped from a sheet of iron is formed into a cylindrical shell after the sheet had had a double fold formed therein to provide a lip around the inside of the container which will form the upper edge of the container after it has been opened. The longitudinal edges of the blank are then connected together to form a seam. The difficulty comes in connecting the edges of the blank at the point where the threefold thickness of the double fold occurs. The patents recommend tapering oil the thickness of the double fold by appropriately shaping the blank in order that the ends of the double fold may overlap in the region of the seam without forming an additional thickness. At the same time, there is formed in the vicinity of the part of the container which will be removed to permit removal of the cover a lateral extension of the blank which, when the blank is formed into a cylindrical shell, will form a tab lying against the outer surface of the cylindrical shell to form a tab to which a slotted key can be fitted to tear out a portion of the container to open it.

While the necessity of using a seamed container has obvious drawbacks, including the difliculty of forming a perfect seal and the operations of forming the blank into a cylindrical shell, the manner of forming the tab is convenient. However, the material of the sheet in that area into which the tab projects is substantially all waste, inasmuch as there is no corresponding point on the other end of the blank into which this tab fits. Thus the blanks cannot be stamped out in an interlocking pattern.

It is an object of the present invention to provide a container which has the advantages of the seamless container relating to the ease of production, ease of hermtic sealing, and at the same time has a means of removing the cover which is similar to the use of the tab on the container of the prior art but which uses no extra material and causes no waste of material. In addition the container of the present invention is provided with a construction by which the cover, after it is once removed and the hermetic seal is broken, can be replaced on the container to close it.

The disadvantages of the prior art containers are eliminated in the case of the container according to the invention. This is achieved according to the invention by forming the shell from a light-metal tube which is continuous over the whole of its circumference and is preferably drawn. In contrast with the known containers which have been mentioned above, the container according to the invention has no longitudinal seam crossing the circumferential folding and is made of light-metal,

this material allowing the circular folding to be formed on the tubular shell blank.

The absence of the longitudinal seam furthermore oifers the additional advantage of enabling the bottom end and/0r top to be fitted more easily to the tubular shell, and of making the problem of obtaining a tight joint between the shell and the bottom end respectively the top easier to solve.

The process for the manufacture of the container and a preferred embodiment thereof, given by way of example, are described in the following with reference to the drawing. In the various figures shown the same parts are always designated by the same reference.

In the drawing:

Figs. 1, 2, 3 and 4 illustrate four different successive phases of the manufacturing process of the container according to the invention;

Figs. 5, 6, 7 and 8 are sectional views, corresponding to Figs. 1-4, showing the last four phases of manufacture, the finished container being shown in Fig. 8;

Fig. 9 is an enlarged partial sectional view taken on line 9-9 of Fig. 10; and

Fig. 10 is a partial side view of the parts shown in section in Fig. 9.

For the manufacture of the container use is made of a blank which may, for instance, have the shape shown in Fig. 1. It is supposed that the cup shaped blank 1 has been formed by drawing a piece of alloyed aluminium sheet, so that it has a cylindrical part 1 and a bottom part 2. The free edge 3 of the blank has already been cut to the correct dimension.

This blank is now provided, as may be seen in Fig. 2, in the neighbourhood of the free edge 3 with a channel 4, preferably by means of a dishing operation carried out on the rotating blank with rolls. After this, the blank being kept rotating, the channel is given an unsymmetrical shape as shown in Fig. 3, by means of appropriately form-ed tools. The profile 5 of the channel is now composed of a short steeply inclined flank 6 and a longer flank 7 which is only slightly inclined in relation to the wall of the blank 1. Two parallel circumferential score lines 8 and 9 are now cut on the inside of the blank above the channel 5 (Fig. 4). A strip 11 of sheet metal lies between these score lines and, as will be described later on, will serve as tear strip. All these phases of the process are carried out on the trimming machine.

After the above described steps have been carried out, the channel is narrowed to a fold and then, as shown in Figs. 5 and 6, laid in an upward direction against the inner side of the container wall. In order to do this, the two flanks 6 and 7 are brought together by means of a press so that an upwardly inclined fold 22 with a folding line 23 is formed. After the fold has been bent over (Fig. 6) the folding line 23 is situated slightly above the score line 9, and this has the advantage that after the tear strip 11 has been removed, the container has no cutting edge which would prevent it from being subsequently used again. In addition a slight outwardly projecting bulge is formed below the folding by means of a pressing, dishing or similar operation.

After the bottom part 2 has been cut oif, the upper and lower edges 25 and 26 are formed in small flanges (Fig. 7). Finally the bottom part proper 27 is fitted and its edge is rolled and pressed together with the flange 26 in the usual way. After the container has been filled, the top 29 is also fitted and secured in the same manner. When the container is finished, the score line 8 is situated at the same level as the lower edge 30 of the seam securing the top. The purpose of the inwardly projecting bulge 28 may be seen below.

As shown in Figs. 9 and 10, a portion having a thickness less than the thickness of the shell 1, e. g. a score line 35, defining a tab 36 is provided on the outside of the Container, one end 38 of this score line being situated at the same level as the inner score line 8, whereas the other end 39 lies in the neighbourhood ofthescore line 9. At the end of the tongue 36, i. e. in the middle portion of the tear strip 11, the score line 35 is broadened to form a region 37 also of reduced thickness and able to be pierced, which may for instance be pierced by the end of a container opening key 40 ground to form a screw-driver edge 41. The tongue-shaped score line 36 and the weakened region 37 are all that can be seen from the outside of the container. After the tool has been thrust through at the point 37, the tongue 36 can be slightly raised and its end introduced into the slit 42 of the container opening key, after which the tongue 36 and the strip 11 can be rolled up with ease.

In order that the key may' be able to pierce the portion of reduced thickness, the top 29 has a depressed central portion extending into the interior of the shell. This portion has a diameter less than the inner diameter of the shell 1 so that there is defined between the depressed portion and the portion of the shell 1 above the top edge of the double fold at 23 an annular space. The diameter of the depressed central portion is substantially equal to the inner diameter of the double fold, so that when the stop 11 has been removed, the depressed central portion will fit tightly into theinside of the doublefold.

This arrangement is particularly advantageous because the container is absolutely hermetieally sealed and is very simple. The score lines 8 and 9 could of course be formed on the outside of the container, and the ends 38 and 39 of the score line 35 would then run directly into the score lines 8 and 9.

In other embodiments ofthe container the bottom part could be in one piece with the shell. In addition it would also be possible, instead of drawing the blank, to obtain it for instance by extrusion.

What I claim is:

A filled metal container comprising a seamless cylindrical shell hermetically closed at its lower end and a top member hermetically sealed to the upper end of said shell, said shell having a continuous circumferential double fold formed from the shell itself around the shell near the upper end thereof and lying against the inner wall of the shell, said shell having two spaced score lines around the interior of the shell between said fold and the upper end, one of said score lines lying in the portionof said shell against which said fold lies immediately below the upper edge of said fold and the other fold line lying between the upper edge of said fold and the upper end, said shell further having a portion of a thickness less than the thickness of said shell I defining the outline of a tab between said score lines,

and said top'havinga' depressed central portion extending into the interior or said shell and having a diameter less than the inner diameter of said shell and substantially equal to the inner diameter'of said double fold,

said depressed portion and the shell above said double fold defining an annular space therebetween, whereby a' tool may be inserted into said space through said portion of reduced thickness to lift the tab and remove the part of said shell between said score lines.

References Cited in the file of this patent

Images