US3411690A - Container bodies - Google Patents

Description

Nov. 19, 1968 WALSH ETAL 3,411,690

CONTAINER BODIES Filed July 29, 1966 in van tors dbl: 71 E. Wa Ish Frederidc 8 \Sillars By their Afzorney United States Patent 3,411,690 CONTAINER BODIES John E. Walsh and Frederick S. Sillars, Beverly, Mass.,

assignors to United Shoe Machinery Corporation, Boston, Mass., a corporation of New Jersey Filed July 29, 1966, Ser. No. 568,507 4 Claims. (Cl. 229-45) ABSTRACT OF THE DISCLOSURE A container body comprising a tube of sheet material with opposite marginal portions of the sheet forming a side seam including an end lap in which opposite marginal portions are in overlapping relationship. The outer overlapping marginal portion of the end lap is notched to provide a tapered end portion and the inner overlapping marginal portion of the end lap is deflected outwardly to engage said outer marginal portion to establish a predetermined spacing between the end lap marginal portions and to facilitate flanging the end of the container.

This invention relates to tubular container bodies and, more particularly, to container bodies having side seams at least an end portion of which is of overlapping or laptype construction. Specificaly the invention resides in the construction of lap seams at the ends of tubular containers in the are where the container is flanged to facilitate the attachment of a bottom and/ or cover.

Conventional tin cans are commonly manufactured from a flat, rectangular blank of sheet stock which is formed into an open ended cylinder by interlocking narrow marginal portions of opposite parallel edges of the rectangle to produce a juncture called the side seam. The interlocking side seam extends lengthwise of the cylindrical body to a point inwardly of each of the open ends where the marginal portions of the edges are secured by an end lap seam. The purpose of the lap seam portions in can bodies of this type is to facilitate flanging of the ends of the can bodies by reducing the number of layers of metal at the side seam which must be flanged. That is, in cross-section, measured radially of the can, the interlocked side seam includes four layers of metal whereas the end lap seam includes only two layers. Flanging is a necessary prerequisite to attachment of a bottom and cover to the open ends of the cylinder.

Conventional container bodies made of composite body stock, i.e., that formed from sheets of metal foil and plastic or fibrous board stock such as chip board, donot readily lend themselves to the formation of an interlocked seam. Accordingly, composite container bodies are almost exclusively in the form of wound bodies or lap seam bodies.

Applicants previously have disclosed a novel container body of the lap seam type and a method of making the same in their copending application for Letters Patent of the United States Ser. No. 456,322, filed May 17, 1965. The container body disclosed in this prior application essentially comprises a tubular container body having a longitudinally extending side seam formed by overlapping the marginal portions of the sides of the body stock, the overlapping portions or layers being secured together by adhesive. The edge of at least one of the overlapping layers is deflected toward and engageable with the other layer to create a predetermined separation between the layers. The width of the separation measured in a direction transaxially or generally radially of the tubular body is between .001" and .015". Adhesive is deposited on the marginal portions in such thickness as to occupy the entire width of the .001 to .015 separation.

3,411,690 Patented Nov. 19, 1968 The result is a container body of considerable durability.

In the preferred embodiments illustrated and discussed in the referenced application, the above described lap seam extends through the entire longitudinal length of the can body. That is, the edge of at least one of the overlapping layers is deflected along its total length from one end of the container body to the other end. Thus, in order to flange an end of a container constructed in accordance with applicants referenced application, the terminal portion or end of the deflected layer(s) has to be bent over and included as part of the flange. Consequently, a resulting flange end has a marked bulge at the side seam area. The bulge essentially prohibits the attachment of symmetrical and enclosure members, i.e. can tops and bottoms.

Applicants found that in order properly to flange the ends of a metal container constructed in accordance with the teachings of their prior application the deflection of the overlapping layer(s) had to be terminated inwardly of the ends of the container. Unless this was done conventional end closure members could not normally be utilized and, indeed, flanging itself was frequently impossible.

Applicants initially attempted to solve this problem by terminating the deflection of the overlapping layer(s) inwardly of the can ends and notching the abutting end laps. Notching essentially comprises removing or cutting away a portion of the overlapping margins at opposite ends of the can body. The cuts were made at an angle with respect to the edge of the margin or overlapping layers to provide a tapered juncture between the can and the margin edge. Notching in this manner is conventional practice at the end laps on can bodies having interlocked side seams. Notching reduces the area to be flanged in which two overlapping layers of material exist and distributes the stresses created by flanging away from a single line of contact.

Notching in this manner did not, however, completely solve applicants problem. Although the bulge at the side seam was essentially eliminated, a high incidence of side seam failure at and adjacent to the flanged area resulted during the flanging operation. Further, leakers were common in the flanged area at the side seam and the area immediately adjacent thereto when pressure and similar tests were conducted on container bodies which had apparently survived flanging. The concentration of relatively high stresses at the side seam during flanging were the apparent reason for the inadequacy of this approach. That is, in bending the two overlapping, notched marginal layers suflicient stress was concentrated at the side seam to break the adhesive bond between the abutting end laps. The stress build up was so substantial as not only to effect the flanged area but also the side seam immediately adjacent thereto. Means were required which would reduce the stress build up and, also, provide a bond of suflicient strength to insure the integrity of the side seam.

Applicants invention is particularly directed to the solution of the problem encountered in research activity relating to the disclosure of their prior application. However, as will be patently clear from the description to follow, applicants novel solution is equally applicable to any container body having a side seam including an end la-p.

Accordingly, an object of this invention is to provide a tubular container body having a side seam including an end lap constructed to facilitate flanging of the end of the container body.

Another and more specific object of this invention is to provide a tubular container body having an adhesively secured side beam of lap-type construction including end laps in which the thickness of adhesive in the seam intermediate the end laps is controlled and in which the structure of the end laps facilitate flanging of the ends of the container without the build up of excessive stresses.

To these ends and in accordance with the objects of this invention there is provided a container body comprising a tube of sheet material with opposite marginal portions of the sheet forming a side seam including an end lap in which the opposite marginal portions are in overlapping relationship, the outer overlapping marginal portion of the end lap being notched to provide a tapered end portion and said inner overlapping marginal portion being deflected outwardly to engage said outer marginal portion whereby a predetermined spacing is established between said marginal portions and said inner marginal portion is deflected in a direction which facilitates and aids in the flanging of the container end.

The above and other features of the invention including various novel details of construction will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular container body embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope of the invention.

In the drawings:

FIG. 1 is a perspective view of a sheet used in making container bodies in accordance with this invention;

FIG. 2 is an edge view on an enlarged scale and partially broken away taken in the direction of the arrow II;

FIG. 3 is an end view, on an enlarged scale, of the side seam including the end lap construction of this invention;

FIG. 4 is a perspective view of the end of a container body illustrating the end lap construction of this invention;

FIG. 5 is a sectional view taken along the line IV-IV of FIG. 4; and

FIG. 6 is a view similar to FIG. 5 after a flanging operation has been performed on the end of the container body.

The description to follow will be with particular reference to container bodies of the type disclosed in the above referenced application. However, as stated above, applicants invention is applicable to any container body having an end lap.

FIG. 1 shows a body blank B which initially comprised a flat rectangular sheet of conventional tin plate, i.e. sheet steel plated on both surfaces with tin. The blank may also be of aluminum, other ferrous or non-ferrous materials or composite metal and fiber laminates. The adhesive utilized in the preferred embodiment is an organic thermoplastic material. However, the use of solder, cement and other adhesive materials is within the purview of this invention.

The upper surface of the blank 12, i.e. that which faces the viewer in FIG. 1, is designated surface i and the lower or opposite surface is designated 0. They are so designated since they are the surfaces which will ultimately constitute the inside and outside of the tubular body. The blank B has opposite parallel edges 2 and 4 and ends 6 and 8. Marginal portions and 12 extending transversely of the blank B adjacent the edges 2 and 4 are overlapped in the body making procedure to be hereinafter described. The opposite ends of the marginal portion 10 or ends 6 and 8 are notched or cut adjacent to the edge 2 to provide tapered junctures 16, 18 between the ends 6 and 8 and the edge 2. The opposite ends of the marginal portion 12 are deflected downwardly, as viewed in FIGS. 1 and 2, to provide spacing and force relieving lips 20, 22 as hereafter discussed in detail. The lips 20, 22 are deflected downwardly, as viewed in FIG. 1, so that they will project or flare outwardly in a formed, unflanged can body, as seen in FIGS. 3 and 4.

The edges 2 and 4 are mutually deflected away from each other and, thus, away from opposite surfaces of the sheet by bending or burring (see particularly FIG. 2). It is to be noted that this bending or burring is accomplished on the edge 4 inwardly of the lips 20, 22. The deflection of the edges 2 and 4 is accomplished in accordance with the disclosure of the above referenced application.

Organic thermoplastic material of any convenient composition is applied in a band 30 about 4 wide to one or both margins beginning at the edges 2 and/ or 4. This may be done either after or before deflection of the edges 2 and 4 is completed.

To form a container body, the blank B is bent or curved into tubular configuration as discussed in the referenced application. The margins 10 and 12 are positioned in overlapping relationship to form a lap seam. The edges 2 and 4 are preferably located in engagement with the surfaces 0 and i, respectively, see FIG. 3. The amount of overlap of the margins 10 and 12 is preferably approximately measured circumferentially of the body.

As particularly illustrated in FIGS. 3 and 4, the lip 22 of the tubular blank B preferably engages the end of the margin 10 proximate to the starting point 32 of the tapered juncture 18. Similarly, the lip 20 (FIG. 1 only) engages the opposite end of the margin 10 proximate to the starting point of the tapered juncture 16 (not shown). The lips 20 and 22, as noted above, project or flare outwardly from the center of the container. The drawings do not illustrate the engagement of the lip 20 with the tapered juncture 16 as such an illustration would merely be repetitive of FIGS. 3 and 4 which show the lip 22. Accordingly, certain of the discussion to follow will be with respect to the lip 22 only, it is to be understood that the construction appurtenant to the lip 20 is identical.

The engagement of the lips 20 and 22 with the mar gin 10 establishes a predetermined gap between the overlapping marginal portions 10 and 12 at the end lap areas. Thus, an amount of adhesive adequate to insure sufficient bond strength is permitted and ensured. Further, as discussed more fully hereafter and in accordance with a prime object of this invention, the outward deflection of the lips 20 and 22 at the end laps reduces the total deflection which must be imposed during flanging thereby reducing the stresses which are built up during the flanging operation. Thus, the possibility of bond failure due to stress build up at and adjacent to the bond area is markedly reduced. That is, as illustrated in FIGS. 5 and 6, the lip 22 is pre-deflected' in the direction that the flanging deflection will occur. Thus, the high initial stresses necessary to produce the flange effect shown in FIG. 6 are reduced. In normal flanging, the highest stresses occur during the period of initial pressure application. This is the time during which the present invention acts to reduce stress. The result is a reduction in the incidence of can body failure at the end lap area.

The end lap area extends inwardly from the end of the can body (FIG. 4) a distance defined by an arcuate or circumferential line parallel to the end 8 which intersects the terminal point 36 of the tapered juncture 18. A similarly defined boundary applies to the opposite end lap with respect to the end 6. By way of clarification of the above discussion, it is again noted that the bending or burring of the edge 4 terminates inwardly of the lips 20, 22. More specifically, the bending or burring is preferably terminated at or inwardly of the circumferential lines which define the end laps on opposite ends of the side seam. In this way, the bending or burring which establishes a predetermined adhesive gap for the major portion of the side seam does not interfere with or impede fianging of the end laps. A predetermined adhesive gap is provided at the end laps, however, by the lips 20, 22 which engage the margin 10 as delineated above.

In an alternative method of fabrication, adhesive 30 may be extruded into the gap between the overlapping layers after the sheet is formed into tubular configuration.

Thus, applicant has provided a can body including an end lap construction which facilitates adequate distribution of bonding material and, contra to the prior art disclosures, aids materially in flanging of the end lap.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. A container body comprising a tube of sheet material with opposite marginal portions of the sheet forming a side seam including an end lap in which the opposite marginal portions are in overlapping relationship, the outer overlapping marginal portion of the end lap being notched to provide a tapered end portion and the inner overlapping marginal portion of the end lap being deflected outwardly to engage said outer marginal portion whereby a predetermined spacing is established between said end lap marginal portions and whereby said inner marginal portion is deflected in a direction which facilitates flanging of the end of the container.

2. A container body according to claim 1 in which the deflected portion of the inner overlapping margin engages the outer overlapping margin proximate to the intersection of said tapered portion with the end of the container body.

3. A container according to claim 1 in which adhesive material is deposited in the spacing between the overlapping layers to seal the seam.

4. A container body comprising a tube of sheet material with opposite marginal portions of the sheet forming a side seam of overlapping layers including end laps at opposite ends of the seam, the edge of at least one of the layers being deflected toward and engageable with the other layer to create a predetermined separation between the layers, said edge deflection terminating inwardly of the ends of the container body proximate to the end laps, the outer overlapping marginal layer of each end lap being notched to provide a tapered end portion and the inner overlapping marginal layer of each end lap being deflected outwardly to engage said outer end lap marginal layer whereby a predetermined spacing is established between said end lap layers and whereby said inner layers are deflected in a direction which facilitates fianging of the ends of the container, and adhesive material in the separation between the marginal layers to seal the seam.

References Cited UNITED STATES PATENTS 1,844,825 2/ 1932 Seifert 220-- 2,064,537 1'2/ 1936 Groenke 220-75 2,185,057 12/1939 Fink 2075 DAVID M. BOCKENEK, Primary Examiner.

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