This invention relates to packaging. More specifically, the invention relates to a multi-sided container or box made of corrugated paperboard. In particular, the invention relates to a corrugated paperboard tray for containing poultry products, wherein the tray is configured for manual set up and has an improved self-locking feature for retaining the walls of the tray in erected position.
Various styles of containers, including paperboard boxes, are known in the prior art for containing a variety of products. Cut poultry pieces, for example, are frequently packed in a paperboard container, and sometimes the poultry pieces are packed with ice. These containers are generally referred to as poultry trays, and are usually made from a unitary blank of corrugated paperboard, which may be treated on one or both sides with wax or other material to impart rigidity and resistance to water degradation.
Conventional paperboard containers are configured for either machine set up or manual set up, and generally are either rectangular or octagonal in plan view, with four sides or eight sides, respectively. An example of a prior art eight-sided container is disclosed in applicant=s prior U.S. Pat. No. 5,752,648. The embodiment shown in FIGS. 1 and 3 of that patent is configured for manual set up, and has three overlapping end panels 18, 24 and 24, with notches 30 formed in the top edges of the two end panels 24, and a roll-over flap 34 foldably joined to the top edge of end panel 18 by short narrow webs formed between transverse cuts or relief slits 37 extending in spaced relationship transversely across cut lines 36 and 38, and interrupting the cut lines. Pairs of short cuts or slits 39 are formed in the webs parallel to the cut lines 36 and 38, but spaced from one another on opposite sides of the cut lines a distance approximately equal to the combined thickness of the three overlapped end panels. The slits 39 promote bending or folding of the webs along fold lines extending through the slits.
To erect the container, the two end panels 24 are folded inwardly into overlapping registry with one another, and the end panel 18 is then folded into overlapping relationship with panels 24. The roll-over flap 34 is then folded inwardly and downwardly over the upper edges of the panels 24, causing the webs to drop into notches 30, and the upwardly extending portions of panels 24 on opposite sides of the notches to project upwardly through the cuts formed by the cut lines 36 and 38. The relationship of the relief slits 37 and cut lines 36 and 38 causes a “heel” to be formed on the edge of the roll-over flap, and this heel produces an over-center effect when the roll-over flap is folded over the panels 24. The heel engages against the inner surface of the innermost end panel 24 to keep the roll-over flap in its folded position, and thereby maintains the container in erected condition.
While the arrangement disclosed in U.S. Pat. No. 5,752,648 provides a simple and effective self-locking system for holding the container in its erected condition, the thickness of the material of the webs causes them to take a slightly “rounded over” shape as they are pulled down into the notches 30, and they tend to exert a pull on the roll-over flap in a direction to disengage it. Additionally, in order to insure that the webs and related components can be operatively engaged with one another, specific dimensional relationships are maintained between the distance from the bottoms of the notches to the bottom of their associated panels 24, and the distance which the relief slits 37 extend above the cut lines 36 and 38, i.e., the length of the relief slits is slightly exaggerated, contributing to a “loose” fit between the components of the self-locking arrangement.
A solution to this was offered in applicant's co-pending patent application, published Mar. 13, 2003, under publication number US-2003-0047592-A1. The container disclosed in this application is similar to that used in U.S. Pat. No. 5,752,648, but is modified to achieve a tighter fit between components of the self-locking arrangement and provide a more reliable interlocking of the components. More specifically, the container disclosed in US-2003-0047592-A1 has a bottom wall, opposite side walls, and opposite end walls, with means on the end walls that interlock to hold the container in its erected condition. The container is made from a unitary corrugated paperboard blank having a bottom panel that forms the bottom wall, opposite side wall panels foldably joined to opposite sides of the bottom panel and that form the side walls, and end panels extending from opposite ends of the bottom panel and side wall panels, respectively, at least some of the end panels overlapping to form the end walls. At least one notch is formed on an upper edge of at least one of the end panels, and a roll-over flap is formed on an upper edge of another end panel, in positions to interlock with one another when the end panels are folded into operative relationship with one another to form an erected container.
In particular, the self-locking structure in US-2003-0047592-A1 has a plurality of notches formed in the edge of at least one end panel, defining at least one tab projecting upwardly from the edge of the panel, and the roll-over flap is foldably joined to its associated end panel by webs formed between a cut line that lies parallel to the fold for the roll-over flap, and relief slits that extend transversely across the cut line. The webs are adapted to lie in the notches, with said at least one tab projecting into a slot formed by the cut line when the roll-over flap is folded inwardly and downwardly over the end panels. The webs are at least partially crushed on the side thereof that faces downwardly in the notches so that they lie substantially flat in the notches. In addition, the dimensional relationships of the self-locking arrangement are made tighter to affect a tighter fit between components, producing a more reliable interlock. Specifically, the distance from the bottom of the notches to the bottom of their associated panels is made smaller than in a tray having a conventional self-locking arrangement, and the length of the relief slits is also made smaller.
However, the prior self-locking roll-over flap as disclosed in the co-pending patent application identified above, and as illustrated in
Accordingly, there is need for a self-locking arrangement that provides a tight, secure fit between components, and that does not come unlocked under stress, insuring that a container incorporating the arrangement reliably remains in its erected condition.
The invention is a paperboard container of the type having a self-locking roll-over flap on at least one wall, wherein the roll-over flap is foldably joined to an outer wall panel by a roll-over panel. The top edge of the roll-over panel has an extended heel portion that abuts against an adjacent end panel top edge to hold the roll-over panel in position. In particular, according to the present invention, a “hook” or shaped recess is formed in the edge of one or more of the tabs formed on the end panel top edges to engage an edge of the roll-over panel and act as a positive detent against the edge of the roll-over panel and prevent it from opening.
More specifically, the container of the invention has a bottom wall, opposite side walls, and opposite end walls, with means on the end walls that interlock to hold the container in its erected condition. The container is made from a unitary corrugated paperboard blank having a bottom panel that forms the bottom wall, opposite side wall panels foldably joined to opposite sides of the bottom panel and that form the side walls, end flap panels extending from opposite ends of the side wall panels, and end wall panels extending from opposite ends of the bottom panel, at least some of the end panels overlapping to form the end walls in accordance with the invention. At least one notch is formed on an upper edge of at least one of the end flap panels, and a roll-over flap is formed on an upper edge of the end wall panel, in positions to interlock with one another when the end panels are folded into operative relationship with one another to form an erected container.
In particular, a plurality of notches are formed in the edge of at least one end flap panel, defining at least one tab projecting upwardly from the edge of the panel, and the roll-over flap is foldably joined to its associated end wall panel by webs formed between a cut line that lies parallel to the fold for the roll-over flap, and relief slits that extend transversely across the cut line. The webs are adapted to lie in the notches, with said at least one tab projecting into a slot formed by the cut line when the roll-over flap is folded inwardly and downwardly over the end panels.
The webs may be crushed on the side thereof that faces downwardly in the notches so that they lie substantially flat in the notches. In addition, the dimensional relationships of the self-locking arrangement are made tighter to affect a tighter fit between components, producing a more reliable interlock. Specifically, the distance from the bottom of the notches to the bottom of their associated panels is made smaller than in a tray having a conventional self-locking arrangement, and the length of the relief slits is also made smaller.
The “hook” or shaped recess noted above, and which represents an improvement over the invention disclosed in co-pending published application US-2003-0047592-A1, is formed in the edge of one or more of the tabs formed on the end flap panel top edges to act as a positive detent against the edge of the roll-over panel and prevent it from opening under stress.
A further aspect of the container disclosed and claimed herein is a crushed area formed in the top panel of the container cover adjacent the fold joining the end panel of the cover to the top panel. This crushed area provides a relief space for the inwardly folded end flaps that are connected to the side panels of the cover, and captured by the roll-over flap or panel in an erected cover, enabling a more accurate fit of the cover and avoiding bowing of the sides when the cover is folded into erected condition. This feature is particularly useful when the slit in the cover blank that separates the end flaps from the end panel is made in axial alignment with the score line that joins the side panel to the top panel, since in this configuration there is a very tight fit between the panels when folded. Additionally, the material along each side of the slit is crushed to provide adequate space to enable the panels to be folded together.
A still further aspect of the container disclosed and claimed herein resides in the locking tab that projects downwardly from the end walls of the cover and which engage in the handholds in the ends of the box when the cover is in place to help retain the cover on the box. In the present invention the locking tab has a lower free end with a downwardly and outwardly directed rounded wing on each of the opposite sides of the free end. The end of the tab between the wings has an arcuate, concave shape. In use, the wings and arcuate end on the tab facilitate flexing of the end of the tab through the handholds, and the concave arcuate shape facilitates insertion of a finger or fingers behind the end of the tab to retract the tab from the handhold.
The invention is a simple, economical and effective way to reliably interlock components of a self-locking arrangement in a container constructed for manual set up. It adds no cost to the container.
The invention is described in greater detail hereinafter with reference to the drawings, wherein like reference characters designate like parts throughout the several views, and wherein:
A rectangular or four-sided container incorporating the self-locking means disclosed in co-pending published application number US-2003-0047592-A1 is depicted at 10 in
The container 10 comprises a bottom wall 11, opposite parallel side walls 12 and 13, and opposite parallel end walls 14 and 15. Each end wall comprises two end panel flaps 16 and 17 foldably joined to opposite ends of respective side walls, and an end wall panel 18 foldably joined to the end of the bottom wall. In this regard, it should be understood that the end flaps each can extend the full width of the end wall, or only partially.
A plurality of notches 20 are formed in each end flap panel 16 and 17 along an outer edge, which becomes the upper edge when the container is set up, forming a pair of upwardly projecting tabs 21 and 22.
A roll over flap 23 is joined to the outer, or upper, edge of end wall panel 18 by a plurality of webs 24 defined by cuts or relief slits 25 and 26 made transversely across a cut line 27, and interrupting the cut line, which extends completely across the width of panel 18 except at the webs 24. Short fold promoting slits 28a and 28b are made parallel to the cut line 27 on opposite sides thereof in locations to define the length of the webs when the roll-over flap is folded into its operative, locked position. In other words, the slits 28a and 28b initiate folding at opposite ends of the web along fold lines extending through the slits. The length of the webs, as defined by the spacing between the slits, and thus between the fold lines extending through them, is substantially the same as the combined thickness of the total number of overlapping end panels.
As indicated by the shading in
To erect the container, the side walls 12 and 13 are folded upwardly, and the end flap panels 16 and 17 then folded inwardly into overlapping relationship with one another. As seen in the drawings, panel 17 is folded inwardly first, although the sequence of folding the two end flap panels is not essential. As folded, the notches 20 and tabs 21 and 22 on the two end flap panels are in registry with one another. The end wall panel 18 is then folded upwardly over the panels 16 and 17, and roll over flap 23 is folded inwardly and downwardly over the upper edge of the end flap panels and end wall panels, causing the webs 24 to drop into the notches and the tabs 21 and 22 to project upwardly through the gap formed by the cut line 27. Because of the spacing of the cuts 25, 26, 27 and 28a and 28b, a “heel” 30 is formed on the roll-over panel in the areas on opposite sides of the webs, and this heel engages against the inner surface of end flap panel 17, holding the roll-over flap in its downwardly folded and locked position inside the panel 17.
The dimensional relationships of the self-locking structure can best be seen with particular reference to
When the roll-over flap 23 is folded downwardly alongside panel 17, the heels 30 extend upwardly and above the fold line that extends through slits 28b, preventing the flap from disengaging from its locked position. To function properly, the upper edge of the heel, when the roll over flap is in its operative folded position, is spaced below the upper edge of the tabs a distance “F” equal to at least the combined thickness of two panels.
The improvement of the present invention is incorporated in the foregoing structure, as depicted in
In the embodiment depicted in
The difference between the present improvement and the invention disclosed in US-2003-0047592-A1 can clearly be seen by comparing
Another embodiment is shown in
A further embodiment is shown in
A blank for forming a cover 50 incorporating the self-locking roll-over flap and hook of the invention is shown in
Another embodiment of a cover 70 incorporating the hook lock of the invention is shown in
Although particular embodiments of the invention are illustrated and described in detail herein, it is to be understood that various changes and modifications may be made to the invention without departing from the spirit and intent of the invention as defined by the scope of the appended claims.
This application claims priority of Provisional Application 60/425,619 filed Nov. 12, 2002.
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Number | Date | Country |
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2144619 | Feb 1973 | FR |
Number | Date | Country | |
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20070138243 A1 | Jun 2007 | US |
Number | Date | Country | |
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60425619 | Nov 2002 | US |
Number | Date | Country | |
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Parent | 10712929 | Nov 2003 | US |
Child | 11592728 | US |