US3756397A - Shrink pack construction and method - Google Patents

Abstract

The invention contemplates employment of a single wrap of a single sheet of continuous shrinkable and bondable plastic material to constitute virtually the entire package for a cluster of plural like containers, such as bottles, beer cans or the like. The sheet material is so selected, sized and oriented with respect to the cluster that timed placement in a shrinking and bonding atmosphere is sufficient to consolidate the package. In orienting the sheet, the sheet circumferentially envelops the cluster, with the ends of the sheet overlapped at the alignment of one of the longitudinal ends of the clustered containers, and a small marginal projection of sheet material is provided beyond the transverse limits of the cluster. In the shrinking and bonding atmosphere, the overlapped ends are bonded, and shrinkage of the projecting margins develops end bands or flanges to retain containers against end loss. Two forms are disclosed, each utilizing a panel of card or paper board.

Description

United States Patent [191 Ganz [451 Sept. 4, 1973 SHRINK PACK CONSTRUCTION AND METHOD [76] Inventor: Robert H. Ganz, 8 Ridge Crest Rd.,

' Saddle River, NJ.

[22] Filed: June 5, 1972 [21] Appl. No.: 259,759

Related U.S. Application Data [63] Continuation of Ser. No. 29,127, April 16, 1970, abandoned, which is a continuation-in-part of Ser. No. 859,904, Sept. 22, I969.

[52] U.S. Cl. 206/65 S, 206/4533, 229/DIG. 12

[51] Int. Cl. 865d 71/00, B65d 85/62 [58] Field of Search 206/65 S, 65 C, 45.33; 229/DIG. 12

Primary Examiner-William T. Dixson, Jr. Attorney-Nichol M. Sandoe, Roy C. Hopgood et a].

[57] ABSTRACT The invention contemplates employment of a single wrap of a single sheet of continuous shrinkable and bondable plastic material to constitute virtually the entire package for a cluster of plural like containers, such as bottles, beer cans or the like. The sheet material is so selected, sized and oriented with respect to the cluster that timed placement in a shrinking and bonding atmosphere is sufficient to consolidate the package. In orienting the sheet, the sheet circumferentially envelops the cluster, with the ends of the sheet overlapped at the alignment of one of the longitudinal ends of the clustered containers, and a small marginal projection of sheet material is provided beyond the transverse limits of the cluster. In the shrinking and bonding atmosphere, the overlapped ends are bonded, and shrinkage of the projecting margins develops end bands or flanges to retain containers against end loss. Two forms are disclosed, each utilizing a panel of card or paper board.

26 Claims, 19 Drawing Figures PATENIEDSEP 4:91: I

saw 1 (if 3 SHRINK PACK CONSTRUCTION AND METHOD This application is a continuation of my copending application, Ser. No. 29,127, filed April 16, 1970 now abandoned, the latter being a continuation-in-part of my original application, Ser. No. 859,904, filed Sept. 22, 1969.

The invention relates to a shrink package for the retained assembly of a cluster of like containers such as beverage bottles or cans; the invention also relates to a method of making such a package.

Today's marketing of bottled and canned beverages and other products calls for suitably packaged clusters or pluralities of such containers, perhaps the most familiar of which is the so-called six-pack." The package must safely and firmly hold the container, it must lend itself both to readyindependent portability and to bulk stacking for warehousing and shipment, and it must lend itself to reliable and economical massproduction. The advent of shrinkable plastic materials has invited drastic changes from the cardboard packages of the past, but to date no satisfactory structure has been devisedutilizing such materials as the primary element of the cluster package.

' It is accordingly an object of the invention to provide an improved container construction and method of the character indicated.

Another object is to provide an improved shrink package and method, in which cluster retention and in tegrity are achieved by a single sheet of shrink material.

A further object is to meet the foregoing objects without the need for any special treatment of the sheet material to make it shrinkable.

A specific object isto achieve the foregoing objects with relatively soft low-density polyethylene sheet.

Another specific object .is to provide a cluster package of the character indicated wherein a minimum of paperboard provides protection againstshearing the plastic sheet, regardless of the number of tiers of clusters that may stand upon each other in bulk packaging for shipment, as on a flat or pallet for fork-lift handling.

Still another specific object is to provide a cluster package of the character indicated wherein local fretting, snagging or tearing of the plastic sheet at vertical load-bearing points is inoperative to disrupt the integrity of the cluster, and yet wherein manual tearing at another location provides ready access to a container selected from the cluster.

A still further specific object is to provide a cluster package of the character indicated wherein a minimum of paperboard reinforcement provides substantial reinforcement to both the structural integrity of the cluster and for the manual lifting and portability of the cluster.

It is a general object to achieve the foregoing objects with a structure that is basically simple, which represents extreme economy in manufacture, and which is applicable to the clustered packaging of various kinds of bottles and containers, with or without chimed end formations.

Other objects and various further features of novelty and-invention will be pointed out or will occur to those skilled in the art from a reading of the following specification, in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

FIG. 1 is a perspective view from above showing a package of the invention, serving a cluster of six like containers;

FIG. 2 is a view similar to FIG. 1, but with the package inverted so as to reveal structural features at the bottom of the cluster;

FIGS. 3, 4 and 5 are like simplified perspective diagrams to illustrate steps in the method of the invention;

FIGS. 6A and 6B are like end views of the cluster package of the invention, respectively illustrating appearance before and after a method step;

FIGS. 7A and 7B are respectively an enlarged end view and a bottom view of a cluster, retained by its shrink pack, under a condition of slightly dislocated containers;

FIG. 7C is a graphical presentation to illustrate tension capability as a function of location along a bond of the invention;

FIGS. 8 and 9 are like fragmentary top views of the cluster package of the invention, respectively illustrating appearance before and after a method step;

FIGS. 10 and 11 are views similar to FIG. 1 to illustrate modifications;

FIG. 12 is a view similar to FIG. 11 to illustrate a use of the modification of FIG. 11;

FIGS. 13 and 14 are fragmentary sectional views respectively taken at the planes 13-13 (FIG. 11) and 14-14 (FIG. 12); and

FIGS. 15 and 16 are, respectively, a perspective view to illustrate a further modification, and a plan view of the blank of a part of FIG. 15.

Briefly stated, the invention contemplates employment of a single wrap of a single sheet of continuous shrinkable and bondable plastic material to constitute virtually the entire package for a cluster of plural like containers, such as bottles, beer cans or the like. The sheet material is so selected, sized and oriented with respect to the cluster that timed placement in a shrinking and bonding atmosphere is sufficient to consolidate the package. In orienting the sheet, the sheet circumferentially envelops the cluster,with the ends of the sheet overlapped at the alignment of one of the longitudinal ends of the clustered containers, and a small marginal projection of sheet material is provided beyond the transverse limits of the cluster. In the shrinking and bonding atmosphere, the overlapped ends are bonded, and shrinkage of the projecting margins develops end bands or flanges to retain containers against end loss. Two forms are disclosed, each utilizing a panel of card or paper board.

Referring to the drawings, the invention is shown in application to the packaged retention of a cluster of six like upstanding containers having cylindrical bodies. The containers are arranged as two adjacent arrays, each having three side-by-side containers. In FIG. 3, this cluster is shown on conveyor means 10, just prior to packaging. The cluster comprises containers 11-1- 2-13 in a first elongated array, and containers 14-1- 5-l6 in a second elongated array. These arrays are parallel, and the containers abut tangentially, along their arrays and at the corresponding containers of the adjacent arrays, to define generally diamond-shaped openings between container ends, as at the shaded regions 17-18 in FIG. 2 (and in FIG. 7B).

For reinforcement, for the display of a promotional message, and for other purposes to be explained, a top panel 19 of card or relatively stiff paper board extends over at least the central region of the top of the cluster, being shown in FIG. 1 as substantially coextensive with the top end of the cluster. In FIG. 3, panel 19 is shown of effective width W, (transverse to the elongation of conveyor and length L, (in the direction of conveyor 10) matching the corresponding dimensions of the top of the cluster; except that, in the length dimension, opposed projecting margins of panel 19 extend therefrom and are bent downwardly as integral side flanges 20-21 over parts of the upstanding sides of the cluster, at least in the region of the centrally located containers 12-15. Cut-outs or punchings 22-23 in panel 19 provide finger-access, at diamond-shaped regions 17-18 between containers, to manipulate and carry the ultimate package, as will be understood. A surrounding film 24 of plastic envelops the cluster, including panel 19, and finger-access openings 25-26 are provided in the plastic sheet in the regions of registry with cut-outs 22-23.

The rest of the cluster-package will be better understood from a brief description of the method of making the same.

As a first step (FIG. 3), the containers 11-12 16 are arranged in a cluster, as on the conveyor 10, with the arrays 11-12-13 and 14-15-16 each extending transversely to the conveyor. The panel 19 is positioned in vertical registry with and upon the cluster, as suggested by the arrow 27. Next, as shown in FIG. 4, the sheet 24 of plastic is selected, as by cutting a predetermined length L from a supply roll of width W The plastic sheet of film 24 should be of a shrinkable and bondable variety and preferably of relatively soft texture, such as low-density polyethylene of the blownextrusion type, having a thickness of l to 2 mils, or less. Such plastic sheeting requires no special treatment to establish shrinking properties, being inherently characterized by 10 to 15 percent transverse shrink energy (direction of dimension W and by substantially greater, e.g., 50 to 55 percent, longitudinal shrink energy (direction of dimension L The sheet 24 is laid over the top panel 19, with panel 19 substantially centrally located. The sheet width W is selected to exceed the corresponding cluster dimension W,, so that marginal projections AW of sheet 24 extend alike, beyond the cluster elongation dimension W (see FIG. 5). The sheet 24 is caused to further envelop the upstanding sides of the cluster, at opposed upstanding panels 28-29, and then to complete the envelopment at a region of overlapped ends; the extent of such overlap is designated D in FIGS. 5 and 6A, it being noted that the overlap of the ends of the plastic sheet 24 extends over the central region of the bottom of the cluster.

Having circumferentially wrapped the cluster, with the weight of the cluster bearing upon and thus retaining the overlap D as shown in FIG. 5, the thus-wrapped cluster is exposed to a shrinking and bonding atmosphere; such an atmosphere may be provided by the hot-air environment of an oven through which the conveyor 10 is passed, as suggested by legend at arrow 30 in FIG. 5. The pairs of phantom lines 31-32-33 will be understood to identify pedestal alignments which may form part of the conveyor 10 in order to support the cluster at central regions of the paired sets of containers 11-14, 12-15, and 13-16, respectively, thus thermally shielding spaced local areas of the overlapped sheet ends, so that in the oven environment hot air may have its most ready access to the shrinkable plastic, on the top and upstanding sides of the wrapped cluster, as well as over most of the bottom areas, including the diamond-shaped regions 17-18. The hot-air environment quickly bonds the overlap region D and shrinks the exposed plastic sheet, establishing a skin-tight sheath which hugs to container contours and which substantially reduces the open ends of the wrap, from the undeformed large opening 35 (FIG. 6A) to a final generally oval-edged, reduced opening 36 (FIGS. 1, 2, 6B and 7A). Upon removal from the oven, the package cluster is ready for handling, following a short interval of time for the shrunken plastic to set in its shrunken form, for example, by not attempting to lift the package until about 5 to 15 seconds after oven exposure, depending on the movement of ambient air; in an automated assembly line, this l-minute delay presents no problem because no need exists for individual lifting of a package, it being perfectly adequate to provide continued conveyor or other support from below the cluster.

It will be appreciated that the self-bonding property of the polyethylene sheet 24, in conjunction with the elevated support at spaced means 31-32-33, establishes bonding over a succession of spaced regions along the overlap D. These regions include generally triangular end areas 37-38 as well as the diamondshaped regions 17-18.

In the normal automated handling of containers of the chimed variety, e.g., cans, as shown, it is a usual occurrence for chimes of the cans of one row (e.g., ll-l- 2-13) to interlock in slightly cocked fashion with corresponding chimes of another row, and of course if plastic shrinking and bonding occur in this circumstance, then the resulting packaged cluster might be considered unsightly and capable of impairing the efficient stacking of clusters in larger handling groups, as on flats or pallets. But in practice, neither of these objectionable circumstances occurs, due to the nature of the cluster package itself, as will be pointed out in connection with FIGS. 7A, 7B and 7C.

FIG. 7A is an enlarged end view of a cluster package in which the chimes 40-41 of cans (e.g., ll) of one row have interlocked with the corresponding chimes 42-43 of cans (e.g., 14) of the adjacent row of the cluster; in FIG. 7A, this situation is illustrated at 42, where chimes 40-42 overlap. This chime interlock produces a reduced dimension L in the conveyor elongation direction, and the cans of the two rows are angularly tilted so that they do not sit erect. This also means that the panel 19 does not seat smoothly and continuously on the cap tops. In practice, however, the inherent resilience of the package, as formed, is sufficient to accommodate the peripheral enlargement which results from forced twisting of the cans into chine-to-chime abutment, as exemplified in FIG. 6B, where the reduced dimension L, (FIG. 7A) has been expanded to L (FIG. 6B), with the can axes erect.

FIGS. 78 and 7C illustrate an important reason why the chime-locked assembly of FIG. 7A can be readily displaced to the unlocked and erect arrangement of FIG. 68.

It will be recalled that narrow pedestal supports 31-32-33 on conveyor 10 provide localized bottom support for paired sets of cans ll-l4, etc. These localized support regions are limited to regions of chime overlap 43 (or chime abutment, as the case may be) for each of the paired sets of cans, and the designation G for each of these regions indicates a gap in the continuity of bonding, between end regions 37-38 and the diamond-shaped regions 17-18. Throughout the bonded bottom of the plastic wrap, any given section taken in the conveyor direction, as on the section alignment A-A, will exhibit a tension capability analogous to hoop tension in a ring, and the magnitude of such tension capability (or resistance to forcible hoop expansion) will generally reflect the local extent of bonded overlap of the ends of the plastic sheet. The alignment A-A was selected to reflect a maximum of such tension capability, attributable to selection on the longitudinal diagonal of the bonded diamond shape 17; this maximum tension capability is graphically shown as a maximum on the lobe 17' of the profile graph of FIG. 7C, where the extent of the capability is labeled Residual Tension in L Direction." From this maximum, the residual tension in lobe 17 (corresponding to diamond shape 17) drops off as successive section alignments are considered in the direction to end 37 or in the direction to end 38. For the unbonded gap regions G, there will of course be substantially zero tension capability, and FIG. 7C reflects this fact. Thus, the tension capability profile is characterized by two spaced large central lobes l7-l8, representing the extensive bonded regions 17-18, and by two further spaced but lesser lobes 37'38', representing the less extensively bonded end regions 37-38, whose tension capability is even further reduced by end-effect considerations, suggested by shrunken edge concavities 44-45.

It will be seen that effort to restore the chime-locked cluster of FIG. 7A to the erect and unlocked condition of FIG. 6B is substantially unresisted by the particular bonding arrangement that has been described. This flows from the fact that the alignments on which the chimes must be displaced (e.g., the alignment B-B for cans 11-14) are substantially localized at the gap regions G where the tension-capability profile is zero, and adjacent these regions of zero profile the rise in tension capability is gradual, to the maximums already identified. On the other hand, the described tension capability results in a well-distributed bonding effectiveness which assures can retention in the cluster.

In FIGS. 8 and 9, I illustrate steps in the formation of finger-access openings 25-26 in the plastic sheet 24. In FIG. 8, the sheet material 24 is shown, undeformed, but wrapped around the cluster, and over the panel 19. Prior to shrinking and bonding, the sheet 24 is locally pierced in registry with panel openings 22-23. Preferably, this is a slit 48, formed as by a razor or knife over the central part of each opening 22-23, and the slit orientation is aligned with the direction of lesser shrink energy for the plastic material 24. Upon shrinking and bonding exposure, the slits are expanded to generally circular shape, as shown at 25-26 in FIG. 9. When the ultimate customer needs to select and move his packaged cluster from the retailer's shelf, finger-access is simple and is easily enlarged as may be needed for adequately reinforced grasp at panel openings 22-23, as will be understood.

F 1G. 10 illustrates that substantially the same fingeraccess and portability are available from a construction similar to that already described, except for a more abbreviated top panel or card 19. The panel 19' may be of essentially the width of only the central pair of cans 12-15 and may again exceed the L dimension of the cluster so that integral downward flanges 20-21' are provided within the shrunken plastic sheath. The finger-access cut-outs 50 are notches in the central parts of opposed edges of panel 19', and the described razorslit technique may again be employed to define the tinger-access openings 25'-26' in the plastic sheath.

It will be noted that the panel side flanges 20-21 (or 20'-21') are merely bent from panel stock and that they require no special slitting or other locked engagement with adjacent chime edges of cans. In spite of this fact, the cluster proves to be easily portable when grasped at 25-26'(or 25'-26') and this is believed to be attributable to the integrated tensioning or tension capability of the shrunken single sheet 24, particularly when considered in the central region where lifting stresses are concentrated. The described tension so clamps the flanges 20-21 (20'-21') to the sides of adjacent cans that tension capability of the panel 19 (19) can be relied upon, utilizing the clamped flanges as a reference.

FIGS. 11 to 14 illustrate a further modification, generally resembling the pack of FIG. 10, but operating on a different principle and offering certain advantages. The difference resides in the unflanged central panel 60, of paperboard, instead of the flanged panel 19 of FIG. 10. Construction is otherwise the same and therefore extensive use is made of previous reference numbers to identify the same elements.

In general, the panel may be one of a variety of possible shapes, including shapes conveniently adapted to the profiled display of the beverage-makers popular symbol or logo. Importantly, the panel 60 has no flange; it is sufficiently extensive in the L direction to at least cover the primary central area of overlap with the central pair of cans 12-15; and it is sufficiently elongated in the W direction to at least substantially the extent of the can diameter, especially in the region of adjacency to the finger-access locations 25 '-26', the latter dimension being designated W, in FIG. 11. A convenient shape is shown for panel 60 wherein the opposite ends are semicircular to register with or locate within the top chimes of cans 12-15. Its sides between these ends may be straight and parallel, as shown, and the makers brand may be boldly displayed, as suggested by the X symbol in the drawing. Thus, for stabilized location within chimes at the ends of cans 12-15, the width W, and end curvature of panel 60 are substantially equal to the can diameter but preferably a little less, for ease of chime engagement.

In use, the pack of FIG. 11 is grasped by the thumb and a finger of the same hand, as suggested in FIG. 12. The grasping action is resisted by stiffness of the cardboard panel 60, and this resistance continues when lifting force is applied, with upward bowing of panel 60, thus assuring integrity of the plastic sheet 24 across the grasping span. In FIGS. 12 and 14, such lifting is seen to establish two like but oppositely sloping halves 61-62 in panel 60, thus enhancing the stiff resistance to grasping action. The pack as a whole is lifted, once the center of panel 60 has been raised the distance H, at which point all lifting force is sustained, in tension, by the plastic sheet 24. The tension forces are sustained generally radially outward from the large central region of panel 60, and stresses are well-distributed. Undue stress-concentration is avoided in this region, since proximity of the panel 60 to the plastic sheet 24 inhibits heat-shrinkage of sheet 24, as compared to those areas of sheet 24 which are merely air-backed. The toughness of the polyethylene sheet, even when of l-mil thickness, is more than enough to sustain lifting forces, even under abusive conditions.

FIGS. and 16 illustrate a still further modification, resembling the forms of FIG. 10 and of FIGS. 11 to 14, but involving certain further features. The difference lies in the use of side flanges 70 at the ends of the central panel 71 of paperboard, the flanges being apertured at 72 to provide a means of locating on the end corners or chimes at the central pair of cans 12-15. The apertures 72 are rectangular, and panel 71 is scored at 73 along the alignment of the inside edge of aperture 72. The span S between these alignments is less than the maximum combined span of the tops of cans 12-15, so that the bends of the chimes project 10- cally through apertures 72 and so that the comers at 73 will not interfere with smooth and continuous conformance of the plastic sheet 24 to the outer chime contours. Moreover, shrinkage of sheet 24 to such an assembly is better able to bend the outer ends 74 of flanges 70 to the side curvature of cans 12-15, as suggested in FIG. 15. The central section of panel 71 is shown slightly reduced, for easier grasping, in the manner described in connection with FIG. 12. And when thus grasped and lifted, the outer edges 75 of apertures 72 will be seen to enable the flanges 70 to engage the sides of the cans 12-15 and thus provide tensed reinforcement to the tensed support relied upon in the shrunken sheet 24, as already described.

It has been generally indicated that in massproduction of packages of the invention, there is no real problem presented by the fact that some or most of the packages may have tilted cans by reason of chime interlock, as in FIGS. 7A and 7B. Bulk shipment of the packaged clusters may assume a variety of forms, any of which will inherently correct the difficulty, due to the described inherent yieldability of the package to accommodate slight reorientation of the cans within the package. In one manner of bulk shipment, involving six-packs" as described, four clusters are grouped in each of one or more tiers of groups in a carton, and the cartons are stacked and tiered on a pallet, for fork-lift or other handling. In that event, all but the packaged clusters in the top tier of the top carton will be subject to the weight load of the tier or tiers above, such load being more than adequate, in application over each panel 19, to force tilted cans to erect position in order to avoid load concentration at high corners, such as the corners 51-52 in FIG. 7A. Load force applied to each such corner establishes such an overturning moment as to disengage the chime interlock and to enable the full rim of each chime or can end to sustain uniformly distributed vertical loading.

It will be noted that the described construction enables the reorientation of tilted cans to be accomplished without subjecting plastic sheet to direct shearing action of loaded metal parts. For example, without the panel 19 the lower chimes of cans in an upper cluster would have nothing but plastic film between them and the top chimes of cans in the adjacent lower cluster, and the described reorientation to erect the cans from tilted condition could cause the vertically adjacent chimes to shear the film. In the first place the card or panel at the top of each cluster provides a stiffening, bearing and load-distributing function that effectively insulates the plastic film layers from such shearing action; and in the second place, any shearing, snagging or the like that occurs for this or any other reason in the course of handling will occur at a localized portion of the bottom, and certainly not at one of the spaced bonded regions 37-17-18-38. On the other hand, ready access to one or more of the individual containers of the package is had merely by laterally spreading one or both opposite sides of an opening 36, to tear the plastic.

The described packages and methods will be seen to have achieved the above-stated objects, producing neat and stout retention of the containers in the cluster. The ultimate in neatness follows from presenting no directly visible seams for normal viewing, the only seam being at D over the central part of the bottom, being the region where resistance to abrasion and abuse is most useful. Extreme economy flows from the ability to utilize cheap plastic sheet for its inherent shrink-energy capability, without further treatment. Other shrink atmospheres may be employed, but the hot air provided in a converyor-line oven is perfectly adequate, as when the unshrunk, wrapped package of FIGS. 5 and 6A utilizing 1.5-mil low-density polyethylene is subjected to an oven temperature of about 350 to 400F. in a passage of 7 to 8 seconds duration.

In one actual employment of the invention for wrapped six-pack clusters of chimed cans, the cluster (and therefore panel 19) top-area dimensions are W,=8 inches and L,=5% inches. The downward projection of flanges 20-21 is about one inch, and preferably such flanges extend continuously from points of substantial tangency to the adjacent outermost cans 11-13 (14-16) of the cluster. The unshrunk dimensions of the plastic sheet 24 have been found satisfactory for a sixpacks of cans having a standard height H of 4 13/16 inches, when W =l0 inches and L =22 inches. This produces l-inch margins AW available to shrink and reduce to the circular closure 36 the respective transverse ends of the plastic wrap, and approximately 2 inches are available for the bonding overlap at D.

While the invention has been described in detail for the packages and containers shown, it will be understood that, not only can modifications be made without departure from the invention, but also the invention is directly usable in the packaging of clusters of chimeless cans, and bottles of metal, glass or plastic, and other types of container.

What is claimed is:

1. A packaged cluster of plural like upstanding containers, comprising a panel of relatively stiff board substantially covering the included area of at least the central part of the top end of the cluster, and circumferential wrap of shrunk plastic sheet extending continuously over said panel and over said top end of the cluster, said plastic sheet also extending over adjacent opposite upstanding sides of said cluster and bonded at spaced locations along ends which overlap each other in the generally central region of the bottom end of said cluster, said sheet having an undeformed width dimension exceeding and projecting beyond the transverse limits of said cluster, whereby in shrunk condition the projecting portions of the sheet envelop at least parts of the transverse limits of said cluster, with doublethickness material bonded at spaced locations in the central parts of said bottom end, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

2. A packaged cluster according to claim 1, in which said panel includes at opposite sides thereof downwardly extending side flanges respectively overlapping at least part of the corresponding opposite upstanding sides of said cluster.

3. A packaged cluster according to claim 1, in which said panel substantially covers the included area of one end of the cluster.

4. A packaged cluster according to claim 3, in which said panel includes at opposite sides thereof downwardly extending side flanges respectively overlapping at least part of the corresponding opposite upstanding sides of the cluster, at least in theregion of the containers centrally loacted in said cluster.

5. A packaged cluster according to claim 1, in which the number of containers is six, arrayed in two adjacent rows of three adjacent containers.

6. The packaged cluster of claim 1, in which said panel has a maximum dimension of extent short of the corresponding dimension of said cluster.

7. The packaged cluster of claim 6, in which said panel has a second dimension transverse to said maximum dimension and substantially equal to the diameter of a can.

8. The packaged cluster of claim 7, in which said sheet has finger-access openings adjacent transversely opposed sides of said panel.

9. A packaged cluster of plural like upstanding prismatic containers arrayed in side-by-side adjacency along a horizontally extending elongation axis, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over the top ends of said containers and continuously over adjacent opposite upstanding sides of said cluster, said sheet being bonded at spaced locations along longitudinal ends of said sheet which overlap each other at the bottom ends of said containers in the elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array; whereby in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of said array, with double-thickness material bonded at spaced locations in the region of the alignment of the bottom ends of said containers, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

10. The method of packaging a cluster of plural like containers which comprises arranging the containers in parallel-oriented transversely aligned adjacency, selecting a length of shrinkable and bondable plastic sheet material of width exceeding the transverse extent of the cluster, orienting the sheet material over the cluster at one end and both adjacent sides with sheet material projecting continuously beyond both transverse limits of the cluster, overlapping the ends of the sheet in the generally central region of the other end of the cluster, thermally shielding spaced local areas along the region of overlapped sheet ends, and exposing the thus-wrapped and locally shielded cluster to a shrinking and bonding atmosphere for a predetermined period of time.

11. The method of claim 10, in which said plastic sheet is selectively bondable and shrinkable at a temperature above normal room temperature, and in which said atmosphere is air which is heated sufficiently above ambient to promote bonding and shrinkmg.

12. The method of claim 10, which includes the additional steps of selecting a top panel to cover at least a central region of said one end of said cluster, and applying said panel over said one end of said cluster before applying the plastic sheet.

13. The method of claim 12, in which the panel is of greater dimensional extent than one of the dimensions of the top of said cluster and in which the panel ends are down-tumed as integral flanges adjacent corresponding parts of opposite upstanding sides of said cluster, prior to the application of said sheet.

14. The method of claim 13, in which the selection of said panel includes removal of panel material at finger-access cut-outs, said panel being applied to the top of said cluster with the finger-access cut-outs aligned with spaces between containers, and locally puncturing said plastic sheet at the region of its localized registry with the finger-access cut-outs, said puncturing being prior to exposure to the shrinking and bonding atmosphere, whereby the shrinking and bonding atmosphere expands the punctured sheet-material openings and effects a fused peripheral edge defining each of the expanded openings.

15. The method of claim 13, in which the sheet material is characterized by a shrink-energy factor in the longitudinal direction which substantially exceeds the shrink-energy factor transverse to said direction, said puncturing at the cut-out locations being a single slitting on a slit axis substantially aligned with the direction of lesser shrink-energy factor.

16. A packaged cluster of plural like upstanding cy lindrical containers arrayed in paired side-by-side adjacency along a horizonally extending elongation axis, a panel of relatively stiff board elongated to span a centrally located one of said pairs and being of width at least no greater than substantially a container diameter, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster and board, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over the top ends of said containers and continuously over adjacent opposite upstanding sides of said cluster, said sheet being bonded at spaced locations along the longitudinal ends thereof which overlap each other at the bottom ends of said containers in the elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array; whereby in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of said array, with double-thickness material bonded at spaced locations in the region of the alignment of the bottom ends of said containers, and further whereby said sheet'adjacent the elongated sides of said panel is of single thickness, for ready finger-grasping contact with the sides of said panel by local finger entry through said sheet.

17. A packaged cluster according to claim 16, in which the number of containers is six, with said panel spanning the central pair of said containers, said panel extending in the direction across said pair at least no more than the combined span of the containers of said pair.

18. A packaged cluster according to claim 17, in which said containers are chimed at the ends spanned by said panel, and in which the longitudinal ends of said panel are contoured to engage within the chimes of said central pair, whereby the central location of said panel is stabilized.

19. A packaged cluster according to claim 17, in which the longitudinal ends of said panel are apertured and folded downwardly over parts of the opposite outer sides of said central pair, said apertures having adjacent edges spaced by a span less than the maximum combined span of the tops of said central pair, whereby the shrunken plastic sheet may conform directly to the top outer edge curvature of said central pair, substantially unimpeded by the folds of said panel.

20. A packaged cluster of plural containers having opposed longitudinal ends and parallel-oriented in transversely arrayed adjacency, said containers having cylindrical bodies with generally circular bottoms, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over both ends of said containers and continuously over adjacent opposite lateral sides of said cluster with overlap at the bottom of the cluster along a general alignment which extends in the elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array, the overlapping ends of said sheet being bonded at spaced locations along the overlap region, said spaced locations being offset from the centers of said containers; whereby, in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of the array, with double-thickness material bonded at spaced locations in the region of overlap, and whereby the bonded regions between and otherwise offset from container centers assure container contour conformation in the shrunk sheet without undue stress in those regions of the sheet material which are local to bottom outer edges of the cluster.

21. The method of claim 20, in which the spaced shielded localities are positioned along the region of overlap to substantially correspond with the transverse positions of said containers; whereby local bonding is offset from container centers.

22. A packaged cluster of plural like upstanding containers arrayed in side-by-side adjacency along a horizontally extending elongation axis, and a circumferential wrap of shrunk plastic sheet extending continuously over the top end of the cluster, said plastic sheet also extending over adjacent opposite upstanding sides of said cluster and bonded at spaced locations along ends which overlap each other in the generally central region of the bottom end of said cluster, said sheet having an undeformed width dimension exceeding and projecting beyond the transverse limits of said cluster, whereby in shrunk condition the projecting portions of the sheet envelop at least parts of the transverse limits of said cluster, with double-thickness material bonded at spaced locations in the central parts of said bottom end, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

23. A packaged cluster according to claim 22, in which said sheet material is low-density polyethylene.

24. A packaged cluster according to claim 23, in which said sheet material is in the order of l-mil thickness.

25. A packaged cluster according to claim 22, in which said containers have cylindrical bodies with circular bottoms, said bonding being at spaced locations in the direction of said array and at regions removed from but adjacent to the tangential-abutment regions of the bottoms of adjacent containers.

26. A packaged cluster according to claim 25, in which said containers are arrayed as two adjacent arrays on parallel horizontally extending elongation axes, whereby at the bottom ends of said containers the overlapped sheet ends overstand generally diamond-shaped open areas between adjacent bottoms of said containers, said bonding being primarily in said overlapped sheet ends in said open areas.

* t l 41 k

Claims (26)

1. A packaged cluster of plural like upstanding containers, comprising a panel of relatively stiff board substantially covering the included area of at least the central part of the top end of the cluster, and circumferential wrap of shrunk plastic sheet extending continuously over said panel and over said top end of the cluster, said plastic sheet also extending over adjacent opposite upstanding sides of said cluster and bonded at spaced locations along ends which overlap each other in the generally central region of the bottom end of said cluster, said sheet having an undeformed width dimension exceeding and projecting beyond the transverse limits of said cluster, whereby in shrunk condition the projecting portions of the sheet envelop at least parts of the transverse limits of said cluster, with double-thickness material bonded at spaced locations in the central parts of said bottom end, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

2. A packaged cluster according to claim 1, in which said panel includes at opposite sides thereof downwardly extending side flanges respectively overlapping at least part of the corresponding opposite upstanding sides of said cluster.

3. A packaged cluster according to claim 1, in which said panel substantially covers the included area of one end of the cluster.

4. A packaged cluster according to claim 3, in which said panel includes at opposite sides thereof downwardly extending side flanges respectively overlapping at least part of the corresponding opposite upstanding sides of the cluster, at least in the region of the containers centrally loacted in said cluster.

5. A packaged cluster according to claim 1, in which the number of containers is six, arrayed in two adjacent rows of three adjacent containers.

6. The packaged cluster of claim 1, in which said panel has a maximum dimension of extent short of the corresponding dimension of said cluster.

7. The packaged cluster of claim 6, in which said panel has a second dimension transverse to said maximum dimension and substantially equal to the diameter of a can.

8. The packaged cluster of claim 7, in which said sheet has finger-access openings adjacent transversely opposed sides of said panel.

9. A packaged cluster of plural like upstanding prismatic containers arrayed in side-by-side adjacency along a horizontally extending elongation axis, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over the top ends of said containers and continuously over adjacent opposite upstanding sides of said cluster, said sheet being bonded at spaced locations along longitudinal ends of said sheet which overlap each other at the bottom ends of said containers in tHe elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array; whereby in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of said array, with double-thickness material bonded at spaced locations in the region of the alignment of the bottom ends of said containers, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

10. The method of packaging a cluster of plural like containers which comprises arranging the containers in parallel-oriented transversely aligned adjacency, selecting a length of shrinkable and bondable plastic sheet material of width exceeding the transverse extent of the cluster, orienting the sheet material over the cluster at one end and both adjacent sides with sheet material projecting continuously beyond both transverse limits of the cluster, overlapping the ends of the sheet in the generally central region of the other end of the cluster, thermally shielding spaced local areas along the region of overlapped sheet ends, and exposing the thus-wrapped and locally shielded cluster to a shrinking and bonding atmosphere for a predetermined period of time.

11. The method of claim 10, in which said plastic sheet is selectively bondable and shrinkable at a temperature above normal room temperature, and in which said atmosphere is air which is heated sufficiently above ambient to promote bonding and shrinking.

12. The method of claim 10, which includes the additional steps of selecting a top panel to cover at least a central region of said one end of said cluster, and applying said panel over said one end of said cluster before applying the plastic sheet.

13. The method of claim 12, in which the panel is of greater dimensional extent than one of the dimensions of the top of said cluster and in which the panel ends are down-turned as integral flanges adjacent corresponding parts of opposite upstanding sides of said cluster, prior to the application of said sheet.

14. The method of claim 13, in which the selection of said panel includes removal of panel material at finger-access cut-outs, said panel being applied to the top of said cluster with the finger-access cut-outs aligned with spaces between containers, and locally puncturing said plastic sheet at the region of its localized registry with the finger-access cut-outs, said puncturing being prior to exposure to the shrinking and bonding atmosphere, whereby the shrinking and bonding atmosphere expands the punctured sheet-material openings and effects a fused peripheral edge defining each of the expanded openings.

15. The method of claim 13, in which the sheet material is characterized by a shrink-energy factor in the longitudinal direction which substantially exceeds the shrink-energy factor transverse to said direction, said puncturing at the cut-out locations being a single slitting on a slit axis substantially aligned with the direction of lesser shrink-energy factor.

16. A packaged cluster of plural like upstanding cylindrical containers arrayed in paired side-by-side adjacency along a horizonally extending elongation axis, a panel of relatively stiff board elongated to span a centrally located one of said pairs and being of width at least no greater than substantially a container diameter, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster and board, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over the top ends of said containers and continuously over adjacent opposite upstanding sides of said cluster, said sheet being bonded at spaced locations along the longitudinal ends thereof whicH overlap each other at the bottom ends of said containers in the elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array; whereby in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of said array, with double-thickness material bonded at spaced locations in the region of the alignment of the bottom ends of said containers, and further whereby said sheet adjacent the elongated sides of said panel is of single thickness, for ready finger-grasping contact with the sides of said panel by local finger entry through said sheet.

17. A packaged cluster according to claim 16, in which the number of containers is six, with said panel spanning the central pair of said containers, said panel extending in the direction across said pair at least no more than the combined span of the containers of said pair.

18. A packaged cluster according to claim 17, in which said containers are chimed at the ends spanned by said panel, and in which the longitudinal ends of said panel are contoured to engage within the chimes of said central pair, whereby the central location of said panel is stabilized.

19. A packaged cluster according to claim 17, in which the longitudinal ends of said panel are apertured and folded downwardly over parts of the opposite outer sides of said central pair, said apertures having adjacent edges spaced by a span less than the maximum combined span of the tops of said central pair, whereby the shrunken plastic sheet may conform directly to the top outer edge curvature of said central pair, substantially unimpeded by the folds of said panel.

20. A packaged cluster of plural containers having opposed longitudinal ends and parallel-oriented in transversely arrayed adjacency, said containers having cylindrical bodies with generally circular bottoms, and a circumferential wrap of a single shrunk plastic sheet surrounding said cluster, said plastic sheet having a longitudinal axis characterized by a shrink-energy factor which substantially exceeds the shrink-energy factor transverse to said axis, the longitudinal axis of said sheet extending in said wrap transverse to the elongation of said array, namely over both ends of said containers and continuously over adjacent opposite lateral sides of said cluster with overlap at the bottom of the cluster along a general alignment which extends in the elongation direction of said array, said sheet having an undeformed width dimension exceeding and projecting beyond the elongation limits of said array, the overlapping ends of said sheet being bonded at spaced locations along the overlap region, said spaced locations being offset from the centers of said containers; whereby, in shrunk condition, the projecting portions of the sheet envelop at least parts of the elongation limits of the array, with double-thickness material bonded at spaced locations in the region of overlap, and whereby the bonded regions between and otherwise offset from container centers assure container contour conformation in the shrunk sheet without undue stress in those regions of the sheet material which are local to bottom outer edges of the cluster.

21. The method of claim 20, in which the spaced shielded localities are positioned along the region of overlap to substantially correspond with the transverse positions of said containers; whereby local bonding is offset from container centers.

22. A packaged cluster of plural like upstanding containers arrayed in side-by-side adjacency along a horizontally extending elongation axis, and a circumferential wrap of shrunk plastic sheet extending continuously over the top end of the cluster, said plastic sheet also extending over adjacent opposite upstanding sides of said cluster and bonded at spaced locations along ends which overlap each other in the generally central region of the bottom end of said cluster, said sheet having an undeformed width dimensiOn exceeding and projecting beyond the transverse limits of said cluster, whereby in shrunk condition the projecting portions of the sheet envelop at least parts of the transverse limits of said cluster, with double-thickness material bonded at spaced locations in the central parts of said bottom end, and further whereby the stress of shrunk sheet material at bottom outer edges of the cluster is locally reduced in the regions between bonded locations.

23. A packaged cluster according to claim 22, in which said sheet material is low-density polyethylene.

24. A packaged cluster according to claim 23, in which said sheet material is in the order of 1-mil thickness.

25. A packaged cluster according to claim 22, in which said containers have cylindrical bodies with circular bottoms, said bonding being at spaced locations in the direction of said array and at regions removed from but adjacent to the tangential-abutment regions of the bottoms of adjacent containers.

26. A packaged cluster according to claim 25, in which said containers are arrayed as two adjacent arrays on parallel horizontally extending elongation axes, whereby at the bottom ends of said containers the overlapped sheet ends overstand generally diamond-shaped open areas between adjacent bottoms of said containers, said bonding being primarily in said overlapped sheet ends in said open areas.

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