US3545165A - Packaging method and apparatus - Google Patents

Description

Dec. 8, 1970 J. D. GREENWELL PACKAGING METHOD AND APPARATUS l8 Sheet-Sheet 1 Filed Dec. 30, 1968 17970 J. D. GREENWELL 3,545,165

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PACKAGING METHOD AND APPARATUS- Filed Dec. 30, 1968 4 l8 Sheets-Sheet 16 BY f" ATTORNEY Dec. 8,.1970 J. D. GREENWELL 3,545,165

PACKAGING METHOD AND APPARATUS- Filed Dec. 30, 1968 l8 Sheets-Sheet 17 .JOSAJ H MA/IEL G/PEMWLZL, BY 9. m o -Sufla/Qw ATTORNEY Y Dec. 8, 1970 .Lo. GR'EENWELL 3,545,155

' I PACKAGING METHOD AND APPARATUS I Filed Dec. 30, 1968 18 Sheets-Sheet 18 ATTORNEY United States Patent 3,545,165 PACKAGING METHOD AND APPARATUS Joseph Daniel Greenwell, Wilmington, Del., assignor to E. Ldu Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Dec. 30, 1968, Ser. No. 787,844 Int. Cl. B65b 35/54, 53/06 US. CI. 53-26 27 Claims- ABSTRACT OF THE DISCLOSURE Method of continuously packaging articles in a Web of heat shrinkable film wherein the web is wrapped around the articles to form an open-ended tube thereabout and the articles are arranged in spaced package groups or units within such tube including the steps of weakening the web or the tube or both at spaced zones therealong, separating the tube between spaced package groups and along a weakened zone by shrinking the tube adjacent this zone thereby to form a tube section having open end portions extending beyond the ends of a package group of articles, shrinking the open end portions of the tube section into engagement with the articles at the ends of the package group, and finally shrinking the entire tube section into engagement with all the articles in the package group thereby to form a package. Apparatus is provided for performing the above described method of packaging.

BACKGROUND OF THE INVENTION Field of the invention This invention is a package-making method and apparatus and, more particularly, is directed to a novel method of and apparatus for continuously packaging a plurality of articles in heat shrinkable film to provide individual packages each consisting of a group of such articles tightly bundled together.

More specifically, the invention relates to a method of and apparatus for packaging cylindrical articles, such as cans, in heat shrinkable film to form a multipack package consisting of 6 cans (commonly referred to as a 6-pack) by separating a tube of such film wrapped around spaced groups of cans, each group consisting of 6 cans, arranged in 2 rows of 3 cans each, along a weakened zone by shrinking the tube adjacent this zone, and then by shrinking the tube section formed thereby around the 6 cans in the group in a novel manner to form a package.

Description of the prior art Packaging arrangements and bundling and packagemaking apparatus of this general type are old. It is known, for example, to overwrap articles in a web of heat shrinkable film and to sever the overwrapped film between spaced groups of articles to form tube sections which are then shrunk around the group of articles in the tube section to form a package.

US. Pat. 3,381,443 to Copping discloses one such method of and apparatus for packaging articles wherein the articles are overwrapped in a continuous tube of heatshrinkable film. In this patent disclosure, the articles are separated into spaced groups while within the tube which is then shrunk into engagement with the spaced overwrapped groups and the individual article packages are formed by severing the partially shrunken tube between the groups to form individual tube sections which are each shrunk around its group of articles.

In co-pending patent application Ser. No. 483,945,

3,545,165 Patented Dec. 8, 1970 filed on Aug. 31, 1965, another method is disclosed wherein spaced groups of articles are overwrapped in a continuous tube of heat-shrinkable film and packages are formed by severing the tube between the article groups to form tube sections prior to heat shrinking each section into engagement with its group of articles.

These methods require that the tube be completely cut, from top to bottom, between each of the spaced groups of articles while the groups are being moved through the packaging apparatus. This imposes a severe limitation on the packaging speed of the apparatus because it drastically disrupts the continuous operation of such packaging apparatus.

SUMMARY OF THE INVENTION The package-making apparatus of this invention is contlnuous in operation.

Briefly described, the apparatus receives a supply of articles of substantially uniform size; forms the articles into spaced package groups; moves the spaced groups of articles continuously along a given line of movement; weakens a continuously supplied web of heat-shrinkable film at spaced zones therealong; wraps the web around the spaced package groups as they move along the line of movement; seals the overlapped edges of the web together to form a unitary open-ended tube around the spaced package groups as they move along the line of movement; weakens the tube at the spaced zones therealong; separates the tube between the spaced package groups to form tube sections each having open end portions which extend beyond the ends of each package group by selectively shrinking the tube adjacent the weakened spaced zones; shrinks the open end portions of each tube section into engagement with the articles at the ends of each package group of articles; and, then, further shrinks each entire tube section into close engagement with all of the articles in its package group to form packages.

In the multipack packaging systems for packaging beer or soft drinks, one of the major requirements is that the package making apparatus or machine be capable of operating at high speeds. In such systems, speeds up to 1200 cans per minute or above should be obtainable. This means that in packaging the classic 6-pack (i.e., 2 rows of 3 cans each) the packaging machine must turn out over 200 6-packs per minute, thus requiring a package travel speed of up to and exceeding feet per minute through the machine.

Obtaining such high speeds is a diflicult mechanical task. This is particularly so if any of the packaging machine operations are other than substantially continuous. For this reason, it is highly desirable to avoid any drastic intermittent motions which would greatly decrease the high speed capabilities of the machine.

In known packaging machines, for example, it is old to wrap a tube of film around cans in groups of 6 after which the tube is severed into tube sections each containing 6 cans while the cans and tube are under continuous movement after which the tube section is shrunk about the cans to form the 6-pack package. The severing operation is accomplished by use of a reciprocating knife which completely cuts the tube as it and the packages are moving at constant speeds. This requires that the knife be capable of both reciprocating and traveling motions because it must cut completely through the tube which means it must move the total distance of the height of such tube in a very short time. This factor alone disrupts the continuous smooth flow of the other operations of the packaging machine and to obtain even reasonably high speeds requires a complex knife mechanism.

Hence, it is seen that the speed of operation of the slowest component of the packaging machine determines the maximum speed of the total machine; and that an intermittent tube cutting or severing operation, for example, may disrupt the continuous nature of the total machine operation, at a great sacrifice to machine speed and efiiciency.

Further, in the packages made by the apparatus of this invention, the cans are not only supported and contained thereby, but form an integral and necessary part of the package providing structural unity and stability to the otherwise unrelated tube or tube section. The bundled articles in the package group are a necessary component of the package so that the positioning of the articles into proper position with respect to each other and to the web wrapped around them must be carried out substantially concurrently to eifect formation of the tube and formation of the package.

From this it is obvious that the speed with which this operation may be accomplished depends upon the speed and continuity of all the other and related operations of the machine including the subsequent tube separating or shrinking operations.

The present invention solves these and other problems existent in the prior art by providing a high speed package making machine of the type described that is completely continuous or substantially continuous in operation and that requires no complete severing of the tube by an intermittently operable cutting knife or other means but which efiiciently and speedily separates the tube into individual tube sections in a novel and inventive manner.

In applicants package making machine, the tube separating operation is accomplished simply by shrinkin the tube along pre-weakened zones selectively formed in the film web prior to its being formed into the tube and, if desired or required, by further weakening the tube by a slight cutting action at or adjacent these weakened zones prior to the shrinking-separating operation thereby to enhance separation. In each instance, the separation of the tube occurs with little, if any, slowdown in machine speed.

It is important to note that the shrinking operation (and the components of the apparatus for performing this operation) that separates the tube into sections also shrinks the open end portions of each tube section into contact with the articles at the ends of a given package group and that both the separating and end shrinking operations occur as the tube and tube sections separated therefrom are being moved in a continuous manner through the package making machine.

Generally, in the Widely used packaging technique for merchandising articles in which the articles are arranged in a sleeve or tube section severed from a tube of heat shrinkable film overwrap and the tube section is shrunk tightly around the articles, the shrinking operation is accomplished by simply passing the overwrapped articles through a conventional shrinking oven maintained at a given temperature. While this one step shrinking method appears to be convenient, it has several severe limitations.

The most prevalent of the disadvantages associated with single oven shrinking techniques centers on the restriction of using a single heat shrinking temperature. This disadvantage can be clearly appreciated when one considers the arrangement of the package and film over- Wrap prior to shrinking. In general, the arrangement comprises an individual package group of the articles in substantially the center of a sleeve or tube section of the [film which is open at both ends. The film generally extends beyond the articles at each end, thus creating protruding areas of film. In the shrinking oven, the protruding areas are shrunk tightly around the ends of the articles while the main body of the film overwrap shrinks around the articles.

However, the amount of shrinking that the film must undergo in various areas is not identical. In general, the protruding areas must shrink up to about 60 percent while the main body of the film shrinks only about 10 to 20 percent. Obviously, a higher temperature is required for shrinking the protruding areas than is required for the main body of the film. However,.when the single oven temperature is set high enough to sufficiently shrink the protruding areas, various properties of the film, such as strength, may undergo deterioration.

Further, in applicants package making apparatus, the tube is separated into tube sections by shrinking, followed by shrinking of such tube sections around the articles. This separation is brought about by selectively directing heat only adjacent the weakened zones of the tube as it moves continuously.

Thus, according to the present invention, there is provided a package making apparatus for directing heated air at substantially only the weakened zones of a tube to separate it into tube sections and then substantially only at the protruding areas of the tube sections whereby these areas are selectively preshrunk without adversely affecting the main body of the tube section. Furthermore, by using the present apparatus, less film overwrap is required per package since the protruding areas can be very tightly and efiiciently shrunk around the package ends.

This is accomplished by providing heat shielding means for preferentially masking the top, bottom and sides of the tube next adjacent each package group (1) during the separating of the tube into tube sections, and (2) during the shrinking of the ends of the tube sections against the articles at the ends of each package group. Such heat shielding means is a part of or is operatively associated with the article and package group conveying means; thus, the continuous movement of the tube and the spaced package groups in such tube (and hence, the continuous operation of the machine) is not affected by the heat shielding operation. It is this combination which particularly adapts the apparatus of the present invention to operate at high speeds, with relative simplicity of motions, and without the use of complex additional parts.

BRIEF DESCRIPTION OF THEv DRAWING FIGS. 1 and 1a are perspective views of the package making apparatus of this invention including an article supply section, a package group forming section, a tube forming section, a film supply and Web weakening section, a tube weakening section, a tube separating and package end shrinking section and a package final shrinking section;

FIGS. 2 and 2a are diagrammatic perspective views of an exemplary drive mechanism for the package making apparatus of FIGS. 1 and In;

FIG. 3 is a perspective view of a preferred package produced by the apparatus of the invention;

FIG. 4 is a plan view showing the tube first forming means of the tube forming section of the apparatus;

FIG. 5 is a partial side elevation of the tube first forming means of FIG. 4;

FIG. 6 is a partial end elevation of the tube first forming means of FIGS. 4 and 5;

FIG. 7 is a partial plan view showing the tube second forming means of the tube forming section of the apparatus;

FIG. 8 is a partial side elevation of the tube second forming means of FIG. 7;

FIG. 9 is an end elevation view of the tube second forming means of FIG. 7;

FIG. 10 is a partial plan view showing the tube second forming means, the tube sealing means and the tube advancing means of the tube forming section of the apparatus;

FIG. 11 is a partial side elevation of the tube second

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