Patent Publication Number: US-10329048-B2

Title: Stackable paperboard container

Description:
FIELD OF THE INVENTION 
     This invention relates to a stackable paperboard container and, more particularly, to a water-resistant stackable paperboard container for produce. 
     BACKGROUND 
     Produce, such as corn, tomatoes and apples, is transported from the site in which it is grown to locations for sale, display, or processing. Portable containers are known that are designed to suit the demands of a particular crop. Known containers may be heavy to transport if made of wood. Wooden or paperboard containers are susceptible to weakening if exposed to moisture and may become contaminated with microbes. 
     SUMMARY 
     A stackable paperboard container is provided and includes a bottom panel, a pair of side panels, a pair of end panels, a pair of side flaps, and a pair of top walls. The pair of side panels extend from the bottom panel and are foldable about a side panel fold line. The pair of end panels extend from the bottom panel and are foldable about an outer end fold line. Each side flap extends from one of a pair of side panels and is foldable about a side flap fold line. Each top wall extends from one of pair of end panels and is foldable about a top wall fold line. Each top wall includes a wall section, a pair of top wall flaps, each top wall flap extending from one side of the wall section and foldable about by a top flap fold line, and a pair of bottom locking tabs, wherein each bottom locking tab extends from each of the pair of top wall flaps along a locking tab fold line and is insertable into a bottom tab slot of the bottom panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying figures in which: 
         FIG. 1  is a top perspective view of a stackable paperboard container taken in accordance with an example of the current disclosure; 
         FIG. 2  is a bottom perspective view of a stackable paperboard container taken in accordance with an example of the current disclosure; 
         FIG. 3  is a top view of a stackable paperboard container taken in accordance with an example of the current disclosure; 
         FIG. 4  is a cross-sectional view of the paperboard container taken along line  4 - 4  of  FIG. 3  in accordance with an example of the current disclosure, showing the gripping flap positioned in the grip; 
         FIG. 5  is a partial cross-sectional view of the paperboard container taken along line  5 - 5  of  FIG. 3  in accordance with an example of the current disclosure, showing a corner support structure and shoulder tabs aligned in shoulder locking slots; 
         FIG. 6  is a cross-sectional view of the paperboard container taken along line  6 - 6  of  FIG. 4  in accordance with an example of the current disclosure, showing a corner support wall, three layers of paperboard, aligned vents, and a gripping flap positioned along a grip; 
         FIG. 7  is a partial cross-sectional view of the paperboard container taken along line  7 - 7  of  FIG. 4  in accordance with an example of the current disclosure, showing the three layers of paperboard; 
         FIG. 8  is a partial cross-sectional view of the paperboard container taken along line  8 - 8  of  FIG. 4  of  FIG. 4  in accordance with an example of the current disclosure, showing the three layers of paperboard and aligned vents; 
         FIG. 9  a partial cross-sectional view of the paperboard container taken along line  9 - 9  in accordance with an example of the current disclosure, showing the three layers of paperboard; 
         FIG. 10  is a partial cross-sectional view of the paperboard container taken along line  10 - 10  of  FIG. 1  in accordance with an example of the current disclosure, showing the three layers of paperboard, the corner support wall  39 , and a bottom tab extended through a bottom tab slot along the side panel fold line  22 ; 
         FIG. 11  is a partial cross-sectional view of the paperboard container taken along line  11 - 11  of  FIG. 1  in accordance with an example of the current disclosure, showing the fold line at a juncture of the bottom panel and the side panel, the corner support wall, and the bottom tab extended through bottom tab slot at the fold line; 
         FIG. 12  is a perspective top view of an unassembled container blank of a stackable paperboard container in accordance with an example of the current disclosure showing the solid elements of the blank; 
         FIG. 13  is a plan top view of the unassembled container blank of  FIG. 12  showing the fold lines and voids of the blank  4 ; 
         FIG. 14  is a top perspective view of the unassembled container blank of  FIG. 12 ; 
         FIG. 15  is a top and side perspective view of the unassembled container blank of  FIG. 12  showing first assembly steps; 
         FIG. 16  is a top and side perspective view of the unassembled container blank of  FIG. 12  show subsequent assembly steps; 
         FIG. 17  is a top and side perspective view of the unassembled container blank of  FIG. 12  showing further assembly steps; 
         FIG. 18  is a top and side perspective view of the unassembled container blank of  FIG. 12  showing further assembly steps; 
         FIG. 19  is a top and side perspective view of the unassembled container blank of  FIG. 12  showing further assembly steps; 
         FIG. 20  is a side perspective view showing the fully assembled container from the unassembled container blank of  FIG. 12 ; 
         FIG. 21  is a side perspective view of multiple stackable paperboard containers arranged on top of each other, the view showing interlocking tabs and slots that allow the paperboard containers to be stacked; 
         FIG. 22  is a partial cross-sectional view of multiple stackable paperboard containers taken along line  22 - 22  of  FIG. 21  showing how immediately adjacent containers may be stacked by aligning the bottom receiving passageway and the stacking tabs; and 
         FIG. 23  is a partial cross-sectional view of multiple stackable paperboard containers taken along line  23 - 23  of  FIG. 21  showing how immediately adjacent containers may be stacked by aligning the shoulder locking slot and the shoulder tabs. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Referring more particularly to the  FIGS. 1-23  in which like numbers refer to similar parts, a stackable, corrugated paperboard container  1  of this invention is shown. The paperboard container  1  generally includes a triangular support  39  in each corner formed of hingedly attached side panels  20  and side flaps  30 , a top wall  50  to at least partially shield the container contents, and top wall flaps  55  having locking tabs  60  to secure the assembled container  1 , as shown. 
     Figures land  2  show the paperboard container  1  assembled for use.  FIG. 21  shows multiple containers stacked in accordance with the features of the invention. 
       FIGS. 12 and 13  show an unassembled container blank  2  which, when assembled using the indicated fold lines, forms the stackable paperboard container  1 . The blank  2  is a single thickness of corrugated paperboard, having, as desirable, one, two, or more plies of corrugations, a choice that depends on the strength required of the assembled container. One of skill in the art of paperboard containers will recognize that alternative types of materials used to make containers, such as plastic, coated fiberboard, and cardboard, may also be used to form the blank  2 . When corrugated paperboard is used it is preferred that the corrugations are positioned to run perpendicular to the fold line between a side panel and the bottom. 
     The blank  2  is die-cut and folded to minimize waste and unutilized areas of corrugated paperboard. In a first embodiment of the invention, the blank  2  is cut to outside dimensions of 49 3/16″×44″. Unless otherwise indicated, other dimensions given herein will be with regard to the first embodiment of the invention. 
     The assembled container  1  is generally rectangular. Therefore, the blank  2  has a rectangular bottom panel  10  as shown in  FIGS. 1-3, and 12-21 . The blank  2  is symmetrical with regard to a central longitudinal line and is also symmetrical to a central horizontal line, these lines (not shown) intersecting perpendicularly at the center of bottom panel  10 . In this description, one of ordinary skill in the art will understand that elements with like numbers reflect that symmetry. The term “inner” refers to elements or surfaces more proximate to this intersection and the term “outer” refers to elements or surfaces more distal to this intersection of central longitudinal and central horizontal lines. The term “middle” refers to an element or surface positioned between an inner and outer element or surface in the assembled container. 
     In a first embodiment of the paperboard container  1 , the dimensions of the bottom panel  10  are 15½″×12¾″. The side panels and end panels, as described in greater detail below, complete the assembled container  1 , as shown particularly in  FIGS. 1-2, 4-6, and 14-21 . 
     The bottom panel  10  has a side panel  20  extending along a side panel fold line  22  on one longer side of the bottom panel  10  and a second side panel  20  extending along a side panel fold line  22   b  on the opposing longer side of the bottom panel  10 . Two base cuts  24  are located within each side panel fold line  22 . When container  1  is assembled, the base cuts  24  form a bottom slot  12  to receive a locking tab  60  described below. When assembled, the paperboard container  1  has a vertical height determined by the height of the side panel  20 , i.e., of  9 ″ in a first embodiment. 
     A outer support panel  25  extends along a middle panel fold line  26  from each short length of the side panel  20 . The middle panel fold line  26  extends from each corner of the bottom panel  10  toward the outer edge of each side panel  20 . A stacking tab  28  is located on the outer support panel  25  that, when the container  1  is assembled, will be received into a tab receiving passageway  54  as described below. 
     A side flap  30  extends from each side panel  20  along a side flap fold line  32  and opposite the bottom panel  10 . Within the side flap fold line  32 , formed of two parallel scored lines, is situated on the blank  2  generally centrally an air receiving passageway, hereinafter referred to as a aperture  73 . 
     Between the outer ends of the side flap fold line  32  and fold line A is a slot  34 , the cutting of which forms a shoulder tab  36 . When the paperboard container  1  is assembled, the side flap  30  is folded at the side flap fold line  32  to pivot 180 degrees and is positioned against the inner surface of the side panel  20 . Upon this action, the aperture  73  now forms a half circle on the container wall and the shoulder tabs  36 , on either side of the aperture  33 , will be received into a shoulder locking slot  58 , as described below. 
     Each side flap  30  is scored at fold line A and fold line B to form corner support  39 . An inner end panel  35  extends from each side flap  30  at fold line B. A stacking tab  38 , located on the inner end panel  35 , will be received into a tab receiving passageway  54  as described below when the paperboard container  1  is assembled 
     A outer support panel  25  extends from each side panel  20  along the middle panel fold line  26 . A stacking tab  28 , located on outer support panel  25 , will be received into a tab receiving passageway  54  as described below when the paperboard container  1  is assembled. 
     The blank  2  has an outer end panel  40  extending along an outer end fold line  42  at each short side of the bottom panel  10 . Each outer end panel  40  has a grip  44 . A hand flap  45  extends from each outer end panel  40  along a hand flap fold line  46 . 
     A top wall  50  extends from each of the pair of outer end panel  40  along a top wall fold line  52 . Each top wall  50  is comprised of a top wall section  51  from which a pair of top wall flaps  55  extend from along a pair of top flap fold lines  56 . A shoulder lock slot  58  is located in the top wall section  51  adjacent to the top wall flap  55  and along top flap fold line  56 . Upon assembly, the shoulder lock slot  58  will receive shoulder tabs  36  located on each side panel  20  and each side flap  30 . In top wall section  51  adjacent to the top wall fold line  52  is a tab receiving passageway  54  to receive stacking tabs  28  and  38  located respectively on each outer support panel  25  and each inner end panel  35  as described above. The top wall section  51  is indented at its midpoint width and expanded at its juncture at the top flap fold line to accommodate the shoulder slot  58 . 
     A bottom locking tab  60  extends from each top wall flap  55  along a locking tab fold line  62 . The bottom locking tab  60  will be received into the bottom locking slot  12  described above. 
     Ventilation passageways  70  (herein after referred to collectively as “vents”  70 ) are situated within panels  10 ,  20 ,  25 ,  30 ,  35 ,  40 , and  55  in a shape and as located by one of ordinary skill in the art to affect air flow and humidity. The vents  70  are positioned on each panel so that, when the paperboard container  1  is assembled, the vents on adjacent panels, if any, are aligned. Aligned vents are of like shape. In the first embodiment long vents  71  are shown in  FIGS. 1-2, 4-5, and 12-21 . In the first embodiment, short vents  41  are shown in  FIGS. 1-2, 6, and 12-21 . In the first embodiment, the aperture  73  is shown in  FIGS. 1-2, 4, and 13-21 . In the first embodiment, grip vents  47  are shown in  FIGS. 1-2, 6, and 12-21 . In the first embodiment, bottom vents  18  are shown in  FIGS. 1-3 and 12-21 . 
     Now referring particularly to  FIGS. 14-20 , assembly of the stackable paperboard container  1  will be described. As shown in  FIG. 14 , each side flap  30  on either side of bottom panel  10  is folded at the side flap fold line  32  and brought about 180 degrees to lie on the inner surface of the side panel  20 . This creates opposing double layered sidewalls. It also aligns the long vents  71  of the side panels  20  and of the side flaps  30 . 
     As shown in  FIG. 15 , each outer support panel  25  is folded at the middle panel fold line  26  at a 90° angle. Each inner end panel  35  is folded about fold lines A and B to create the corner support  39  to run diagonally at the juncture of the outer support panel  25  and the inner end panel  35 . 
     As further shown in  FIG. 16 , fold each side panel at the side panel fold line  22  so that the bottom panel  10  and each side panel  20  are at a 90° angle to each other at their juncture. 
     As shown in  FIG. 17 , fold each end panel  40  at the outer end fold line  42  so that the bottom panel  10  and each end panel  40  are at a 90° angle relative to each other at their juncture. Arrange the outer support panels  25  and inner end panels  35  to rest along the outer end fold line  42 , an action that positions the corner support  39  in place at each of the four corners. This action creates opposing triple layered end walls. It also aligns the grip  44  of the outer end panel  40  with the grip vents  47  of the outer support panel  25  and the outer end panel  35  and aligns the short vents  41  in the outer end panel  40 , outer support panel  25 , and the inner end panel  35 . 
     As shown in  FIGS. 17 and 18 , fold the top wall  50  toward the opposite end of the paperboard container  1  at a 90° angle at top wall fold line  52 . Arrange stacking tab  28  (on the outer support panel  25 ) and stacking tab  38  (on the inner end panel  35 ) to be received through the tab receiving passageway  54  of top wall  51 . As shown in  FIGS. 18 and 19 , arrange shoulder tabs  37  to be received in shoulder locking slot  58 . 
     As shown in  FIGS. 18 and 19 , fold the top wall flap  55  toward the bottom panel  10  along top flap fold line  56  at a 90° angle so that the top wall flap  55  lies against the outer surface of the side panel  20 . This action forms a triple layer wall. Fold the bottom tab  60  along the locking tab fold line  62  a 90° angle relative to the top wall flap  55  and insert the bottom tab  60  into bottom slot  12 . This action secures the container  1  in an assembled form. 
     As shown in  FIG. 21 , the fully assembled container  1  can be stacked by aligning (1) the stacking tabs  28  and  38  of a lower container  1  with the bottom receiving passageway  14  of an immediately adjacent upper container  1 , and (2) the shoulder tabs  37  of a lower container  1  with the shoulder locking slots  58  of an immediately adjacent upper container  1 . 
     The folding of fold lines A and B on inner end panel  35  and side flap  30  in conjunction with the 90° angle at the middle panel fold line  26  of the outer support panel  25  create a triangular support at each corner support  39  of the paperboard container  1 . This combination contributes greater strength to the paperboard container  1  than a container without the combination. 
       FIGS. 3-11 , particularly with the cross-sectional views, and  FIGS. 14-20 , particularly showing the steps used in assembling the paperboard container  1 , are useful in identifying the locations of double- and triple-layer wall construction used in the paperboard container for increased strength as compared to single-wall container construction. 
     The  FIGS. 1-23  also indicate the location of stacking tabs  28 ,  38  (which are received into tab receiving passageways  14 ), and side flap locking tabs  60  (which are received into the bottom tab slots  12 ), and the shoulder tabs  36  (which are received into shoulder lock slots  58 ) that are involved in stacking and locking the paperboard container  1  when assembled. 
     The inter-fitting elements at the top wall  50 , end panel  40 , and bottom panel  10  of the immediately adjacent lower and upper containers allow containers to be stacked for storage, display, and transport. The top wall section  51  provides at least a partial cover to protect produce (or other contents) contained in the paperboard container. The assembled container  1  is secured in an assembled form when bottom tab  60  is inserted into bottom tab slot  12 . 
     The paperboard container  1  may be formed of any suitable materials, including, but not limited to cardboard, fiberboard (i.e., corrugated fiberboard), etc. In one embodiment, the paperboard container  1  is formed by first stamping the blank  2  out of paperboard and then imparting or scoring fold lines to the blank  2 . The paperboard container  1  is preferably formed by an integrally-formed blank  2 . 
     Water-resistant corrugated paperboard is manufactured and used for shipping produce, wet iced poultry, meat containers, and a variety of other end uses where the board is exposed to water or high humidity. Conventional water-resistant corrugated paperboard is generally prepared by first assembling the various layers of the corrugated paperboard in a corrugator using specially-formulated adhesives that have higher resistance to water than conventional paperboard adhesives. 
     Water-resistant paperboard adhesive is prepared through a variety of techniques that generally focus on a higher rate of carrier application and higher solids content. Stein-Hall adhesives are generally used for the water-resistant paperboard adhesive. As known in the art, a Stein-Hall adhesive uses a small portion of cooked carrier starch to suspend and carry uncooked starch. The Stein-Hall adhesive also uses caustic soda (sodium hydroxide) to help cook the carrier starch, and borax to increase tack and cohesiveness. These three raw materials, and water, are the main ingredients for all corrugating adhesives. Their consistency will affect the quality, stability, and running qualities of the finished adhesive. 
     A waterproofing agent may be of any type that is known in the art for coating corrugated paperboard. Typically, the waterproofing agent comprises a waxy material suspended in a solvent such as water. After drying the corrugated medium that are treated with the waterproofing agent, the solvent is removed with the waxy material remaining on or in the corrugated medium. One example of a suitable waxy material, for purposes of the instant invention, is polyethylene terephthalate (PET). However, it is to be appreciated that different waxy materials can be used, and it is to be further appreciated that different waterproofing agents may be used to treat the corrugated medium. Corrugated media formed in the presence of the waterproofing agent are readily known in the industry. 
     A preferred water resistant outside coating is SS 48 Spectra (Spectra-Kote Corporation, 301 E. Water Street, P.O. Box 3369, Gettysburg, Pa. 17325-0369). A preferred water resistant corrugated paperboard is Norshield waxless board (Cascades Containerboard Packaging, 55-15 Grand Avenue, Maspeth, N.Y., United States, 11378). 
     The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.