US3517475A - Method of packaging - Google Patents

Description

June. 30, 1970 A. s. BALOCCA METHOD OF PACKAGING Filed April 18. 1968 INVENTOR.

United States Patent 3,517,475 METHOD OF PACKAGING Alfred Edward Balocca, Wheaton, 11]., assignor to American Can Company, New York, N.Y., a corporation of New Jersey Filed Apr. 18, 1968, Ser. No. 722,352 Int. Cl. B65b 1/24, 31/02 US. C]. 53-22 Claims ABSTRACT OF THE DISCLOSURE In order to prevent paneling or body-wall deformation of a can or like container which is subjected to reduced pressure or vacuum conditions, or to prevent undesired movement of the product Within the container, :1 portion of the can end closure is reshaped to greatly reduce the internal volume of the can after the latter has been sealed with the product therein. The reshaping is facilitated by providing an annular peripheral fold in the end closure whereby mechanical pressure may be readily applied to the end closure to depress a major portion of the latter into the can body as the told is uncollapsed uniformly and evenly to thereby provide a finished package of commercially acceptable appearance.

BACKGROUND OF THE INVENTION This invention relates to a method of packaging products wherein a container is reshaped after it is sealed to greatly reduce the internal volume of the package.

Various food products, such as coffee and non-carbonated beverages, are frequently vacuum-packed in cans. To prevent paneling or body-wall deformation due to atmospheric pressure, it has heretofore been common to form the can of a heavy-gauge metal. This, of course, results in added costs. Another expedient to prevent bodywall collapse, but which permits the use of a relatively light-gauge metal, has been to provide for reshaping of the can after it is packed to reduce the internal volume thereof so that the product supports or tends to support the body of the can. In this latter system, the product is placed within a can, a vacuum is applied to the can and the product to remove the major portion of the air from the can, the can is then sealed while under vacuum, after which the can is reshaped to reduce the volume thereof. This reshaping may be done mechanically, or may, if the can end be suitably profiled to permit flexing, be effected automatically by the imbalance of pressure when the vacuumized can is exposed to atmospheric pressure. The extent of reshaping may be such that the product is forced into compressive engagement with the can body so as to form a support for the can body and prevent paneling thereof.

Paneling or body-wall deformation also tends to occur under other circumstances. For example, after filling and sealing containers made of non-rigid materials (e.g. thermoplastic) with certain types of products (e.g. motor oil, paint), it has been found that the container side walls tend to panel or become deformed when the container has been stored for a period of time. This deformation or paneling results from a reduction of the pressure within the interior of the container. After the container has been filled and sealed, a small amount of air generally remains trapped within the headspace of the container. Upon being stored, the contents of the container may chemically react with or absorb a component, usually the oxygen, of this residual air. Such reactions cause the total pressure within the container to drop and, as a result, the side Wall of the container will flex inward or panel due to atmospheric pressure in order to compensate for this internal pressure drop. When this condition occurs, the container frequently assumes an undesirably distorted appearance and sometimes deforms to such extent that it will not adequately support another container that may be stacked on top of it. In some cases, the container may be filled with a heated product which reduces in volume upon subsequent cooling and which thereby tends to reduce the internal pressure in the sealed container and thus produces deformation of the container body.

According to the present invention, reshaping of the container, after it has been packed and sealed, is facilitated by providing a folded portion on an end closure, whereby mechanical pressure may be readily applied to the end closure to depress the latter into the container body as the folded portion is uncollapsed to provide the additional material needed to make the depression. The folded portion is preferably located closely adjacent the periphery of the end closure so that when it is unfolded, maximum displacement of the closure into the container body is obtained.

SUMMARY OF THE INVENTION In a method of packaging a product into a can or like container, 2. product is placed into the can and an end closure is placed thereon and suitably sealed to the can body. To prevent or minimize paneling or body-wall deformation of the can, the internal volume of the can is reduced by reshaping the end closure after the latter has been sealed to the can body. In order to facilitate such reshaping, the end closure, before it is placed on the can, has a portion folded over on itself so that, after the end closure is sealed in place on the can body, mechanical pressure may be applied to the end closure to effect a fully controlled and uniform uncollapse of the fold, thereby to depress and dispose the major portion of the end closure into the can body. In some cases, the volume of the can may be reduced to the extent that the product is forced outwardly into compressive engagement with the can body so as to form a support therefor. In other cases, a slight pressure above atmospheric pressure may be obtained in the container to retard or prevent paneling.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a container having a top end closure with a collapsed fold.

FIG. 2 is a partial sectional view taken substantially along the line 2-2 of FIG. 1 and also showing a plunger used to uncollapse the top end closure fold.

FIG. 3 is a partial sectional view similar to FIG. 2. showing the end panel after the fold has been uncollapsed.

FIGv 4 is a partial sectional view of various die parts for making a fold in the end closure in a position before the fold is made.

FIG. 5 is similar to FIG. 4 but shows the position of the die parts after the fold has been made.

DESCRIPTION OF THE PREFERRED EMBODIMENT As a preferred or exemplary embodiment of the instant invention, FIG. 1 illustrates a container, generally designated 10, having a tubular body 12. An upper end closure 14 and a lower end closure 16 are secured to the ends of the body 12 in any suitable manner such as well-known doubleseams 18, 20. The bottom closure 16 may be of conventional, well-known construction or may be the same as the top closure 14 to be described more fully hereinafter. In the illustrated embodiment, the container 10 is made of sheet metal (e.g. tin plate, aluminum, tin free steel, etc.). Under such circumstances, the body 12 usually is made from a flat blank which is formed into tubular configuration and its marginal edges joined into a longitudinal extending soldered or cemented side seam 22.

Can bodies, as described above, are well-known in the art and further description thereof is deemed unnecessary. It is to be understood, however, that it is within the purview of the instant invention to have the body 12 made from other materials such as thermoplastic resins (e.g. polyethylene, polypropylene, etc.), or by other methods such as drawing and ironing, impact extrusion, injection molding, and thermoforming. In some of these other procedures, such as thermoforming in the case where the container body is made of a thermoplastic resin, the body will be seamless, thereby obviating the presence of the side seam 22. Also, the bottom closure of the container will be integral with and formed of the same material as the container body, thereby obviating the doubleseam 20.

The upper end closure 14, prior to being collapsed and as shown in FIG. 2, includes a substantially horizontally extending central panel 24 which is recessed within the body 12 and which extends over and covers the major portion of the open end of the container body 12. At its periphery, the panel 24 is bent back upon itself inwardly toward its center and then again outwardly toward the body 12 to form an annular fold 2 6. Thus, the annular fold 26 is composed of three layers of metal in contiguous overlying relation and in contiguous relation with the periphery of the panel 24. It is to be understood that other folding configurations can be used and are, therefore, in the purview of the instant invention. To facilitate double-seaming, the upper surface of the fold 26 is substantially on the same level as the lowermost edge of the doubleseam 18. The fold 26 merges with an upward extending countersink wall 28 which, in turn, merges with a closure flange 30 which is interfolded with a peripheral flange 32 on the body 12 in a well-known manner to form the doubleseam 18.

The fold 26 is made in the end closure 14 prior to the securement of the latter to the container body 12. Thus, the end closure 14 is initially formed into the configuration shown in FIG. 4, wherein the closure flange 30 extends in a substantially horizontal direction on a plane spaced from the horizontal plane at which the central panel 24 substantially lies with the countersink wall 28 disposed therebetween. The countersink wall 28 is joined to an inwardly and downwardly extending annular step 34 which is, in turn, joined to a generally vertical annular wall 36 extending generally perpendicularly from the panel 24. By using suitable dies, as illustrated schematically in FIGS. 4 and 5, the step 34 and vertical wall 36 are collapsed to form the fold 26.

The dies for forming the fold 2-6 consist of a generally cylindrical support tool 38 disposed within the bore of and moveable axially (as indicated by the arrow 40 in FIG. 4) relative to an upper support ring 42, and a generally cylindrical collapsing tool 44 also disposed within the bore of and moveable axially relative to a lower support ring 46. Initially, the die parts are axially separated and the end closure 14, having the configuration shown in FIG. 4, is located on the lower support ring 46. Thereafter, the upper support ring 42 is moved axially to clamp the flange 30 and countersink wall 28 between the two support rings 42 and 46 as shown in FIG. 4. Thereafter, the collapsing tool 44 and support tool 38, having the panel 24 sandwiched therebetween, are simultaneously moved axially relative to the support rings 42 and 46, which remain fixed, from the FIG. 4 to the FIG. position to reshape the step 34 and annular wall 36 to form the fold 26. The support tool 40 precludes inward collapse of the vertical wall 36 of the end panel 14 while a cavity 48 formed by the die parts outwardly of the vertical portion 36 is provided to accommodate the fold 26 as it is being formed. In this regard, it will be observed that the vertical wall 36 of the end closure 14 is the weakest unsupported section within the cavity 48 formed between the die parts so that as mechanical pressure is applied to the panel 24 by the collapsing tool 44, the latter is effective to collapse the vertical portion 36 outwardly (as indicated in broken lines in FIG. 4) within the die cavity 48. The collapsing tool 44 and support tool 40 are brought to the position shown in FIG. 5 wherein the fold 26 has been completely formed within the die cavity 48. Thereafter, the die parts are axially separated for removal of the end closure 14 therefrom. Prior to the application of the closure 14 to the body 12, its flange 30 is edge curled and lined with a suitable compound.

According to one embodiment of the invention, after the container 12 has been filled with a product P and prior to sealing of the end closure 14 to the body 12, the container and product are disposed in a vacuum chamber and the end closure 14 is set in place on the can body in closely spaced relationship above the contents P. The desired vacuum is obtained in the container and the end closure 14 is sealed to the body 12 by a conventional can-closing mechanism (not shown) which forms the doubleseam 18.

The container is then located beneath a mechanical plunger assembly 50 -(see FIG. 2) which includes a vertical, reciprocably mounted shaft 52 on the lower end of which is secured a plunger 54. The latter is of a lesser diameter than the container body 12 and is intended to engage only the upper surface of the end closure panel 24 radially inwardly disposed of the fold 2-6. The plunger assembly 50 is operable to uncollapse the fold 26 and depress the end panel 24 to dispose the major portion of the end closure 14 into the can body (see FIG. 3). As a result, the internal volume of the container is reduced so that the head space in the container is substantially eliminated. In some cases, the inwardly offset panel of the end closure can actually be moved into contact with the container contents to press the latter against the body to support the body wall and prevent collapse thereof, or, if desired, when the contents are solid, to clamp the contents between the opposite ends of the can 10 to thereby prevent undesired, and possibly destructive, movement of the contents within the can.

If the product in the container is of a granular type (e.g. coffee), the product may be compressed and compacted as the depressed panel reaches its full, uncollapsed disposition shown in FIG. 3. When this occurs, a lighter body material may be used in the construction of the container than is normally used in containers of this type when the product is vacuum packed without subsequent reshaping of the container.

In the case of products which are packed under atmospheric conditions, an air-filled headspace frequently exists between the surface of the fluid and the internal surface of the end closure 14 due to the fact that it is not practical or economically feasible to fill the container completely to eliminate all residual air space or voids. It has been found that constituents of certain fluid products (e.g. motor oil) may react chemically with this air within the container in the normal course of storing such a filled container. Such chemical reactions of the fluid result in the reduction of internal pressure in the container in that the reactions use up the oxygen in the head space, and the partial pressure, previously created by the oxygen, is no longer present and, consequently, the internal pressure in the container will be reduced. A similar result of reduced total internal pressure would prevail for chemical reactions between the fluid and any of the other constituents and/ or components of the residual space. Further, after the container is initially filled with a heated product (e.g. motor oil which has been heated to make it less viscous for filling), its subsequent cooling will tend to cause a reduction in the internal pressure. With reduction of internal pressure, the atmosphere or surrounding environment acts upon the com tainer, tending to cause the side wall of the container to buckle or panel.

According to the present invention, the end panel 14 is depressed into the container to the extent of imposing a pressure, above atmospheric, within the container, Thus, by reducing the internal volume of the container after sealing, thereby to take up the head space and impose a positive internal pressure, slightly above atmospheric, paneling is retarded or prevented.

In some instances, as where the product within the container is solid, the controlled collapse of the fold 26 may be utilized to move the panel 24 into contact with the product to clamp it against the opposite end closure in order to prevent undesired, and perhaps destructive, shaking movement of the product within the container.

It will be understood, of course, that collapsed ends of the type herein described may be used on both ends of the body 12 in order to produce a double reduction of the volume within the can.

It is thought that the invention and many of its attendant advantages will \be understood from the foregoing description and it will be apparent that various changes may be made in the steps of the method described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the method hereinbefore described being merely a preferred embodiment thereof.

Iclaim:

1. The method of packaging a product into a container, comprising the steps of:

providing an empty container body and an end closure for said body,

folding a portion of said end closure over on itself,

placing the product in the body,

placing said end closure on said body,

sealing said end closure to the body, and

uncollapsing said fold by appling pressure to the end closure, thereby to depress a portion of the latter into the container body.

2. The method of packaging according to claim 1 wherein said told extends annularly, and said step of applying pressure to the container comprises applying mechanical pressure to said end closure at a location adjacent said annular fold.

3. The method of packaging according to claim 1 wherein said step of forming a fold in said end closure comprises applying a force to press contiguous parts of the end closure into overlapping and abutting engagement.

4. The method of packaging according to claim 3 further comprising the step of forming the fold into three overlapping and abutting layers.

5. The method of packaging according to claim 1 wherein said end closure has a closure flange and a substantially flat central panel with a countersink wall disposed therebetween, said step of folding a portion of said end closure comprises forming a generally sinuously configured section between said central panel and said countersink wall.

6. The method of packaging according to claim 1 wherein said end closure is sealed to the container body under atmospheric conditions.

7. The method of packaging according to claim 1 wherein said end closure is depressed into the container body sufliciently to impose a pressure above atmospheric Within the sealed container.

8. The method of packaging according to claim 1 wherein said end closure is sealed to the container body under vacuum conditions, said end closure being depressed into the container body to the extent that the product is forced into compressive engagement with the container body.

9. The method of packaging according to claim 1 wherein a head space is present in the container between said product and end closure after the latter has been scaled to the container body, said end closure being depressed into the container body to the extent that said head space is substantially eliminated.

10. The method according to claim 1 wherein said fold has a sinuously configured cross section, said fold being uncollapsed by applying mechanical pressure to said end closure in an axial direction.

References Cited UNITED STATES PATENTS 3,056,244 10/1962 Bartels 53-22 X 3,117,873 1/1964 Bartels et a1 53-22 X THERON E. CONDON, Primary Examiner R. L. SPRUILL, Assistant Examiner US. Cl. X.R.

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