Abstract:
A one-piece container formed from a single unitary blank of corrugated paperboard has a bottom wall, opposed side walls and inwardly inclined opposed end walls. Stacking tabs project upwardly from the end walls and tab locks in the bottom wall receive the stacking tabs of a subjacent container when the containers are stacked on top of one another. A reinforcing corner post extends the full height of the container in each corner. The corner posts are formed by panels extending from opposite ends of the end walls, wherein the panels include a first panel foldably joined to an end of an associated end wall and adhered to an adjacent side wall, a second panel foldably joined to the first panel and extending diagonally across the corner, and a third panel foldably joined to the second panel and adhered to an adjacent side wall.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a container for storing and transporting products such as agricultural produce. In particular, the present invention relates to a paperboard container made from a single unitary blank that has the same if not greater stacking strength than current multi-piece designs, has the same outside dimensions as current designs and is able to fit within existing warehouse and storage racking systems, and is able to withstand up to three months in cold storage. 
       BACKGROUND ART 
       [0002]    Containers made of corrugated paperboard are commonly used for storing and shipping agricultural produce. Typically, such containers are formed from a blank scored with score lines and cut lines and have a bottom and opposed sidewalls. As used herein, the term “sidewalls” refers to the side walls extending along opposite sides of a container and the end walls extending across opposite ends of a container. The term “side wall” or “end wall” is used when a particular wall is intended. The blanks are most often formed by automated machines in a continuous in-line process involving cutting, scoring and molding continuous sheets of paperboard. The paperboard is then folded along the score lines and cut lines to form a container. The blanks may be folded into a container by an automated machine or may be set up by hand. 
         [0003]    Conventional containers used within many produce segments typically comprise three-piece Bliss style cartons. These container designs have to be run over two different machines at the box plants, requiring extra manpower to run the machines, and they require extra warehousing for the three pieces and extra labor for set-up at the customer&#39;s locations. 
         [0004]    During use, containers are often stacked on top of one another for ease of shipping and for optimum use of space. For stability in stacking the containers it is common to have stacking tabs extending upward from the top edge of the container sidewalls. These stacking tabs often fit into corresponding notches cut into a superjacent container to help secure the stack. Since containers are usually stacked on top of like-sized containers, the stacking tabs that extend upwardly from a lower container are positioned directly into the sidewalls of a superjacent container. Thus, to accommodate the stacking tabs on a lower container, a complementary notch must be cut out of the bottom edge of the sidewall of a higher container. However, a notch in a sidewall is problematic in that it does not secure the stacking tab on all four sides. Thus, these sidewall notches do not fully prevent side-to-side movement, subjecting the stack to potential toppling. This is sometimes circumvented by having a multi-ply or multi-layer sidewall, wherein a stacking tab extends upwards from an inner layer of the sidewall, thereby aligning the stacking tabs with the bottom panel of an adjacent container as opposed to the sidewall. This, however, requires excess paperboard to be used to create the multi -layer sidewall, and results in related increased costs. 
         [0005]    Further, it is easy to misalign a container during stacking such that a higher container falls into a lower container, usually on an angle, potentially damaging the contents of the lower container. To solve this, several prior art containers have been designed with inwardly inclined sidewalls, wherein the distance between the opposing top edges of the sidewalls is less than the distance between the opposing lower edges of the sidewalls. This eases stacking by severely limiting the probability of the higher container falling into a lower container, since the narrower upper portion creates a more functional ledge for the base of the higher container to rest on. 
         [0006]    Some prior art containers have reinforcing corner posts to increase their stacking strength and to assist in preventing an upper container from falling into a lower container when they are stacked, but applicant is not aware of any prior art container that has both full depth reinforcing corner posts and inclined side walls with stacking tabs. One prior art container with inclined side walls has diagonally extending reinforcing corner panels at the upper margin of the container, but these panels do not extend the full height of the container. 
         [0007]    Other prior art containers have full depth reinforcing corner posts to increase stacking strength, but they do not have inclined sidewalls. 
         [0008]    Applicant is not aware of any prior art paperboard container that has inclined sidewalls, stacking tabs, and full height reinforcing corner posts, and especially such a structure wherein panels extending from opposite ends of the sidewalls are folded to form the corner posts and include sections adhered to adjacent portions of the side walls and end walls. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention comprises a one-piece container made from a single unitary blank of corrugated paperboard. The container has inwardly inclined side walls or end walls, double thickness stacking tabs with vertical corrugations, and full height reinforcing corner posts, wherein panels extending from opposite ends of the side walls or end walls are folded to form the corner posts and include sections adhered to adjacent portions of the side walls and end walls to hold or aid in holding the side walls and end walls in erected position. The stacking tabs extend in coplanar relationship with the associated inclined wall, and in a preferred construction tab locks are scored and cut in the bottom wall of the container for accepting and securing the stacking tabs of a subjacent container. 
         [0010]    The one-piece container of the invention is made from a single unitary blank and is a replacement for the three-piece Bliss style carton currently used within many produce segments. The container has the same if not greater stacking strength than current multi-piece designs, has the same outside dimensions as current designs and is able to fit within existing warehouse and storage racking systems, and is able to withstand up to three months in cold storage. The inclined side walls or end walls of the container and the correspondingly inclined stacking tabs ensure that the stacking tabs fit into the tab locks in the bottom wall panel of a superjacent container and not into the side or end walls of the superjacent container. The tab locks capture the tabs on all four sides, resulting in a secure stack without requiring excess paperboard material. The combination of these features results in containers that are easy to stack and container stacks that are not prone to toppling, without using excess paperboard. 
         [0011]    In a preferred construction the tab locks comprise a cut-out slot coupled with a flap, wherein the flap can bend upwards, thereby better accommodating an inclined stacking tab. Further, as stacking of adjacent containers is only possible if the pattern of the cut-out slots is configured in the same pattern as the stacking tabs, the locks are positioned to engage and lock the stacking tabs in a specific configuration. Therefore, the locks of the present invention can be scored and cut in any arrangement to fit on various arrangements of stacking tabs. For example, the bottom wall panel may contain four locks in a particular arrangement to accommodate four stacking tabs of a particular arrangement. Similarly, the locks may be inwardly spaced at different distances from an outer edge of the bottom wall panel to accept stacking tabs that are inclined at various angles. 
         [0012]    The container of the invention incorporates internal corner posts and an internal minor flap that keep an upper container from nesting into a lower container. The container can be devoid of top flaps or lid panels, or it can have full or partial lid panels. In those embodiments incorporating lid panels, locking tabs on the lid panels engage and lock over the stacking tabs. The tab locks that trap the stacking tabs lock stacked containers to one another. The stacking tabs are of double thickness with vertical corrugations. The style and size of the corner posts can be adjusted for different tray packs but still allow the tray to run on current equipment. 
         [0013]    The container can be made with or without top flaps and the corner posts can be adjusted to fit different product lines. The one-piece design allows the customer to handle less inventory as compared with current styles. The corner posts provide increased stacking strength and prevent containers from nesting into each other when they are stacked. The inclined side walls or end walls provide improved stacking and lock the containers to one another by trapping the stacking tabs in the tab locks of a superjacent container. The locking feature on the top flaps or lid panels prevents the top flaps from opening during shipping and handling. This locking feature also permits the opening and relocking of the flaps for product inspection. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The foregoing, as well as other objects and advantages of the invention, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like reference characters designate like parts throughout the several views, and wherein: 
           [0015]      FIG. 1  is a top isometric view of a container in accordance with the invention. 
           [0016]      FIG. 2  is a side view in elevation of two containers according to the invention stacked on top of one another and showing the inwardly inclined end walls. 
           [0017]      FIG. 3  is a top isometric view of the container of  FIG. 1  with one of the lid panels open. 
           [0018]      FIG. 4  is a greatly enlarged fragmentary top isometric view of one corner of the container of the invention, showing the corner post pad in position to be folded over the top of the corner post in a preferred construction of the invention. 
           [0019]      FIG. 5  is a greatly enlarged fragmentary plan view of one corner of the container, showing the corner post pad folded on top of the corner post. 
           [0020]      FIG. 6  is a plan view of a blank for making the container of  FIG. 1 . 
           [0021]      FIG. 7  is an isometric view of the blank of  FIG. 1  in a first, initial folded state. 
           [0022]      FIG. 8  is an isometric view of the blank in a second folded state. 
           [0023]      FIG. 9  is an isometric view of the blank in a third folded state. 
           [0024]      FIG. 10  is an isometric view of the blank in a fourth folded state, erected and ready to accept product before the lid panels are folded into closed position. 
           [0025]      FIG. 11  is a top plan view of the container of  FIG. 10 , with the lid panels and corner post pads omitted for simplicity of illustration. 
           [0026]      FIG. 12  is an isometric view of the container with one lid panel folded and locked in operative closed position. 
           [0027]      FIG. 13  is an isometric view of the container fully erected with both lid panels folded and locked in operative closed position. 
           [0028]      FIG. 14  is a top plan view of a blank for making a second embodiment of container according to the invention, wherein vent openings are provided in the lid panels. 
           [0029]      FIG. 15  is a top isometric view of a container made from the blank of  FIG. 14 , shown with the lid panels in open position. 
           [0030]      FIG. 16  is a top isometric view of a third embodiment of container according to the invention, wherein the end walls and lid panels are devoid of vent openings, the corner posts do not include a diagonally extending panel, and the corner post pad is omitted. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    A first, preferred form of container  10  according to the invention and a blank B 1  for making it are shown in  FIGS. 1-13 . The container has a bottom wall  11 , opposite side walls  12  and  13 , opposite end walls  14  and  15 , and partial lid panels  16  and  17  folded inwardly from opposite sides of the container. Stacking tabs  18  on the upper edges of the end walls are received in slots  19  in the lid panels, and locking tabs  20  on the lid panels are folded downwardly over the outside of the stacking tabs and against the upper outer edge of the respective end wall to lock the lid panels in closed position. Upwardly extending heels  21  on the locking tabs lie against the outside of the respective stacking tabs to hold the locking tabs in their downwardly folded locked position as shown in  FIG. 1 . The locking tabs  20  and heels  21  are formed by shaped cuts  22  made in opposite ends of the lid panels, and the slots  19  result when the locking tabs and associated heels  21  are folded out of the plane of the respective lid panel. 
         [0032]    As seen best in  FIG. 2 , the end walls  14  and  15  are inwardly inclined, and the stacking tabs  18  on the upper edges of the end walls are coplanar with the end walls so that they are correspondingly inwardly inclined. Further, as seen best in  FIG. 6 , opposite side edges of the stacking tabs are slightly undercut, defining shoulders  23  that aid in retaining the locking tabs in locked position over the stacking tabs. 
         [0033]    Tab locks  24  of the type disclosed in applicant&#39;s U.S. Pat. No. 7,677,454 are cut and scored in the bottom wall  11  adjacent its folded connection  25  with an associated end wall, as shown in  FIG. 6 , or inwardly spaced from fold line  25  a predetermined distance (not shown), depending upon the desired or necessary configuration. Each lock  24  comprises a cut-out slot  26  coupled with a bendable flap  27 , wherein the slot is designed to engage and secure a stacking tab  18  of a subjacent container. To fully engage and accept a stacking tab that enters through cut slot  26  on an angle, flap  27  has the ability to bend upwards along a back cut line  28 . Flap  27  has a length, width and thickness, wherein the thickness is equal to the thickness of the bottom wall  11 , and the length and width can vary within the scope of the invention as long as the flap sufficiently engages a stacking tab to frictionally hold it in the slot  26 . The flap is bordered by contact edge  29 , back cut line  28 , and side cut lines  30  and  31 . Contact edge  29  is the part of the flap that engages and holds secure stacking tabs  18  by rubbing against the tabs and holding them secure with a frictional force. Back cut line  28  is preferably a small cut line upon which flap  27  can pivot, and extends parallel to contact edge  29  and perpendicular to side cuts  30  and  31 . However, the back cut line does not run the full length of contact edge  29 , but is located intermediate and spaced from the side cuts  30  and  31 . In alternate embodiments (not shown), the back cut line is a perforated cut line that runs between side cuts  30  and  31 . Cut lines  30  and  31  are incisions that extend laterally from the back of flap  27  to the fold line  25 , parallel to each other and downwardly though the entire thickness of the bottom wall  11 . The cut lines enable the flap to extend upward about the back cut line without encountering undue resistance from the part of bottom wall panel  11  that borders flap  27 . Contact edge  29  extends from cut line  30  to cut line  31  parallel to fold line  25 , and engages tab  18  when it is inserted through slot  26 , holding the tab securely in place. In the embodiment shown, the contact edge extends in a slight, tongue-shaped outward arc. However, the shape of the contact edge may be altered in other embodiments. 
         [0034]    Cut-out slot  26  extends across fold line  25  from contact edge  29  of flap  27  to an edge  32  in the adjacent end wall panel, and is further bordered by side cuts  30  and  31 . The width of the slot is great enough so that stacking tabs  18  can extend through the slot between the side cuts. However, the length between contact edge  29  and edge  32  may be less than the thickness of the stacking tabs, enabling the tabs to press against a portion of flap  27 , causing the flap to bend upwards to accommodate the tab. 
         [0035]    Each slot  26  is aligned to accept a stacking tab on a slight taper. If the degree of taper changes, the alignment can change accordingly. For example, if end walls  14  and  15  are inclined at a greater angle than shown in  FIG. 2 , the stacking tabs  18  will contact the bottom wall panel  11  of the superjacent container at some point closer to the center of bottom wall panel  11 . To account for this, the slots can be inwardly spaced from fold line  25 , thereby being aligned to accept the tabs. 
         [0036]    Reinforcing corner posts  40  extend diagonally across each interior corner of the container. The corner posts extend the full height of the container and are formed by folded corner post panels on opposite side edges of each end wall. The construction of the corner posts is seen best with reference to  FIGS. 3-11 . 
         [0037]    Referring first to  FIG. 6 , corner post panels  41  are foldably joined to each end of each end wall panel  14 ,  15 . Each flap is divided by spaced apart parallel folds  42  and  43  into first, second and third rectangular panels  44 ,  45  and  46 , respectively. The first panels  44 , positioned contiguous to the associated end wall  14  or  15 , are folded perpendicular to the end wall and adhered to an adjacent inner end surface of an adjacent side wall  12  or  13 . The second panels  45  are folded at an acute angle to the first panels so that they extend diagonally across an interior corner of the container, and the third panels  46  lie against and are adhered to the inner surface of the adjacent end wall. It will be noted that the blank preferably is cut so that the corrugations in the end walls, corner posts and stacking tabs extend vertically. A stacking tab  18 A is on the upper edge of panel  46  and is adapted to lie against stacking tab  18  on end wall  14  or  15  when the container is erected. 
         [0038]    Small corner post pads  47  are foldably joined to the upper edge of the first panels  44 , and these pads are folded over the upper ends of the corner posts as seen best in  FIGS. 4 and 5 . 
         [0039]    The sequence of folding the blank B 1  to form the erected container of  FIG. 1  is depicted in  FIGS. 7 through 13 . Thus, as seen in  FIG. 7 , the panels  44 - 46  are folded so that the first panels  44  extend perpendicular to the associated end wall panel  14  or  15  and the second panels  45  extend diagonally, with third panels  46  lying against and adhered to the associated end wall panel. The end wall panels are then folded up as shown in  FIG. 8  so that they extend perpendicular to the bottom wall panel  11 , followed by folding the side wall panels  12  and  13  so that they extend perpendicular to the bottom wall panel, with the interior end surfaces of the side wall panels lying against and adhered to the first panels  44 . The container is then ready to be loaded with product and the lid panels closed and locked as described previously herein. When the lid panels are folded to their closed positions, the corner post pads  47  fold down and lie between the lid panels and upper ends of the corner posts. 
         [0040]    A second embodiment of container  50  and blank B 2  for making the container are shown in  FIGS. 14 and 15 . This form of the invention is essentially identical to the first form described, except that vent openings  51  are provided in the lid panels  16 ′,  17 ′, the bendable flaps  27  are omitted from the cut-outs  26 , and slight depressions  52  are formed in the upper edges of the end walls  14  and  15  at opposite side edges of the stacking tabs  18 . 
         [0041]    A third embodiment of container  60  is shown in  FIGS. 16 and 17 . This form of the invention differs from the previous forms primarily in that the reinforcing corner post does not extend diagonally but instead panel  45 ′ lies against the adjacent side wall, and the corner post pads  47  are omitted. However, the third panel  46 ′ extends over nearly half the width of the associated end wall. Further, there are no vent openings in the end walls  14 ′,  15 ′ or lid panels  16 ′,  17 ′. 
         [0042]    While particular embodiments of the invention have been illustrated and described in detail herein, it should be understood that various changes and modifications may be made in the invention without departing from the spirit and intent of the invention as defined by the appended claims.