Abstract:
A container for carrying produce having tapered side walls to aid stacking of like containers. The tapered side walls further have tapered stacking tabs extending outwardly from the top of the side walls, co-planar to the side walls. The tapered stacking tabs fit into slots cut-out of a bottom panel of an adjacently stacked container without necessitating cut outs in the side walls of an adjacently stacked container.

Description:
RELATED APPLICATION  
       [0001]    This application claims priority from U.S. Provisional Application Serial Nos. 60/365,481 filed Mar. 19, 2002 and 60/366,475 filed on Mar. 20, 2002, the disclosures of which are incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a container made of a flexible material, erected from a unitary paperboard blank, for the holding, stacking and transporting of various items such as agricultural produce. In particular, the present invention relates to a container having tapered side walls and tapered stacking tabs extending from and co-planar with the tapered side walls, and locks scored and cut in a bottom panel of the container for accepting and securing the tapered stacking tabs of an adjacently stacked container.  
         BACKGROUND OF THE INVENTION  
         [0003]    Corrugated paperboard is typically used in many different applications, for example, to form containers, boxes, cartons, or dividers for holding, storing, stacking or shipping various items such as agricultural produce.  
           [0004]    Typically, such containers have a bottom and four side walls, and are formed from a blank scored with score lines or cut lines. 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 or cut lines to form a container. The blanks may be folded into a container by an automated machine or by a consumer.  
           [0005]    During use, containers are often stacked on top of one another for ease of shipping and for optimum use of space. In these circumstances, it is possible for containers to have stacking tabs extending upward from the top edge of the container&#39;s side walls. These stacking tabs often fit into corresponding notches cut into an adjacently stacked container to help secure the stack. Since containers are usually stacked on top of like sized containers, the stacking tabs that extend upward from a lower container&#39;s side walls position directly into the side walls of a higher, adjacent container. Thus, to accommodate the lower container&#39;s tabs, a complimentary notch must be cut out of the higher container&#39;s side walls. However, a notch in a side wall 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 side wall, wherein a stacking tab extends upwards from an inner layer of the side wall, thereby aligning the stacking tabs with the bottom panel of an adjacent container as opposed to the side wall. This, however, required excess paperboard to be used to create the multi-layer side wall and related excess costs.  
           [0006]    Further, it is easy to misplace 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 patents have devised tapered side walls, wherein the distance between the top edges of the side walls is less than the distance between the lower edges of the side walls. 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. However, with these containers, the tapered side walls do not have stacking tabs, severely lessening the strength of the stack.  
           [0007]    Therefore, it is an object of this invention to provide a paperboard container with a stacking structure that has tapered side walls and stacking tabs that are secured by an adjacently stacked container on all four sides.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention comprises a container preferably used for transporting food items, with a bottom panel, two opposing side walls, two opposing end walls and stacking tabs extending upwardly from either the end walls or side walls, co-planar to the side or end walls. The container&#39;s side walls or end walls are tapered, such that the angles between the side walls or end walls and the bottom panel is less than 90°. As a result, the tabs that extend co-planar from the end or side walls are likewise tapered at the same angle. The container further has locks scored and cut in the bottom panel of the container, wherein the tapered stacking tabs of the container extend through the cut slots of an adjacently stacked container.  
           [0009]    The tapered side or end walls of the container and the corresponding tapered stacking tabs ensure that the stacking tabs fit into slots cut from the bottom panel, and not the side wall, of an adjacent stacking container, thereby allowing the containers to securely stack without requiring excess paperboard material. Further the tapered side walls lessen the distance between the top edges of the side or end walls as opposed to the base of the side or end walls, thereby preventing unwanted slippage by providing a better supporting ledge for a container when it is stacked on top of another. 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.  
           [0010]    One embodiment of the invention includes locks, comprising of a cut out slot coupled to a flap, wherein the flap can bend upwards, thereby better accommodating a tapered stacking tab. Further, as stacking of adjacent containers is only possible if the pattern of the cut-out slots are 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 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 panel to accept stacking tabs that are tapered at various angles.  
           [0011]    Other embodiments include containers with reinforcement flaps made of flexible material such as paperboard. The resultant flaps lie flush against the upper sides of the container, thereby increasing the thickness of the upper sides and any stacking tabs extending upwardly therefrom. The reinforcement flap may also create a supporting ledge along the corners of the container. The supporting ledge and increased thickness of the stacking tabs further increases the strength of a stack and reduces the likelihood of a higher container falling into a lower container in the stack.  
           [0012]    Other objects, embodiments, features and advantages of the present invention will be apparent when the description of a preferred embodiment of the invention is considered in conjunction with the annexed drawings, which should be construed in an illustrative and not limiting sense.  
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES/DRAWINGS  
       [0013]    [0013]FIG. 1 is a plan view of a container blank having tapered side walls and tapered stacking tabs extending co-planar therefrom.  
         [0014]    [0014]FIG. 2 is a plan view of an alternate embodiment of a container blank having tapered side walls and tapered stacking tabs extending co-planar therefrom.  
         [0015]    [0015]FIG. 3 is a plan view of an alternate embodiment of a container blank having tapered side walls and tapered stacking tabs extending co-planar therefrom.  
         [0016]    [0016]FIG. 4 is a perspective view of the container blank of FIG. 3 folded and erected in a container. 
     
    
     DETAILED DESCRIPTION  
       [0017]    A paper or paperboard blank scored in accordance with one embodiment of the invention is shown in FIG. 1. Blank  10  is scored for the purpose of folding into a clamshell container suitable for holding, shipping or stacking a wide variety of objects, such as perishable agricultural products. The blank is preferably a flat corrugated paper or paperboard made of any material known in the art that is suitable for the shipping and transporting of a wide variety of food items. For example, if one were to package heavier materials, a thicker grade may be advisable.  
         [0018]    Bottom panel  12  is a substantially rectangular panel bordered by end fold lines  14  and side fold lines  16 . End panels  18  foldably connect to bottom panel  12  along fold lines  14 , and side panels  20  foldably connect to bottom panel  12  along fold lines  16 . Holes  22  are provided alongside fold lines  16  to provide breathing holes and access for an automated machine to manipulate and fold the blank into a fully erect container. Locks  24  are cut and scored in the bottom panel and may be adjacent score line  14  or inwardly spaced from score line  14 .  
         [0019]    End panels  18  are generally rectangular panels that correspond to end walls when the container is fully erected. Accordingly, the length of end panels  18  in blank  10  corresponds to the height of the end wall  18  in an erected container. In the present example, the length of the end panel is 4¼ inches. However, the length of the panel, and corresponding height of the erected container, can vary widely within the scope of the invention. Each end panel  18  is bordered on four sides by an upper edge line  26 , fold line  14 , and two outer fold lines  28 . End flaps  30  foldably attach to each end panel along fold lines  28 . Stacking tab  32  extends outwardly from outer edge  26 , co-planar to side panel  18 .  
         [0020]    End flaps  30  are substantially rectangular panels bordered on four sides by top edge  64 , side edge  66 , bottom edge  50 , and fold line  28 , wherein the bottom edge  50  of the panel extends laterally at a slightly different angle than the top edge  64 , thereby causing the end panel  18  to taper when the panel is erected. Bottom edge  50  extends generally in the same lateral plane as fold line  14  of end flap  18 , except it diverges with a slight angle toward the top edge  64 . The angle can vary greatly, depending on how much of a taper is ultimately desired in the end panel. In this embodiment, an angle of 1-5° is preferable. Similarly, top edge  64  exists largely in the same plane as top side  26 , except with a slight divergent angle away from bottom edge  50 . The angle of divergence of the top edge is ideally the same as the angle of divergence of the bottom edge. For example, if edge  50  diverges form fold line  14  at an angle of 3°, top edge  64  diverges from top  26  at an angle of 3°. The equivalent angle of divergence allows top edges  26  and  64  to create a flat, even top corner even as the end flap is tapered.  
         [0021]    Each lock  24  on bottom panel  12  has a cut out slot  52  coupled with a flap  54 , wherein the slot is designed to engage and secure stacking tabs  32  of an adjacent container. To fully engage and accept a stacking tab that enters through cut slot  52  on an angle, flap  54  has the ability to bend upwards along a back cut line  56 . Flap  54  has a length, width and thickness, wherein the thickness is equal to the thickness of the bottom panel  12 , and the length and width can vary within the scope of the invention as long as the flap sufficiently engages a stacking tab. The flap is bordered by contact edge  58 , back cut line  56 , and side cut lines  60  and  62 . Contact edge  58  is the part of the flap that engages and holds secure stacking tabs  52  by rubbing against the tabs and holding them secure with a frictional force. Back cut line  56  is preferably a small cut line upon which flap  54  can pivot that extends parallel to contact edge  58  and perpendicular to side cuts  60  and  62 . However, the back cut line does not run the full length of contact edge  58 , instead being a smaller cut line intermediate side cuts  60  and  62 . In alternate embodiments, the back cut line is a perforated cut line that runs between side cuts  60  and  62 .  
         [0022]    Cut lines  26  and  28  are incisions that extend laterally from the back of flap  54  to fold line  14 , parallel to each other and downwardly though the entire thickness of the panel  12 . The side wall incisions enable the flap to extend upward about the back cut line without encountering undue resistance from the part of bottom panel  12  that borders flap  54 .  
         [0023]    Contact edge  58  extends from cut line  60  to cut line  62  parallel to fold line  14 , and engages tab  32  when is inserted through slot  52 , holding it securely in place. In the present embodiment, the top extension extends in a straight line. However, the shape of the extension may be altered in other embodiments. For example, extension  58  can extend in a slight, tongue shaped outward arc. In this circumstance, the outer most portion of the flap, or the portion that is furthest from the crease line, will be the part of the extension that contacts the stacking tabs.  
         [0024]    Cut out slot  52  lies between flap  54  and fold line  14 , and is further bordered by side cuts  60  and  62 . The slot&#39;s width is great enough so that stacking tabs  32  can extend through the slot between the side cuts. However, the length between contact edge  58  and fold line  14  may be less than the thickness of the stacking tabs, enabling the tabs to press against a portion of flap  54 , causing the flap to bend upwards to accommodate the tab.  
         [0025]    Each female slot member 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 side walls  18  taper a higher degree than shown in FIG. 1, the stacking tabs  32  will contact the bottom panel  12  of an adjacent container at some point closer to the center of bottom panel  12 . To account for this, the slots can be inwardly spaced from fold line  14 , thereby being aligned to accept the tabs.  
         [0026]    Side panels  20  are generally rectangular panels each bordered on four sides by an upper edge  34 , lower fold line  16 , and side edges  42 . Side panels  20  correspond to the side walls when the container is fully erected. Accordingly, the length of side panels  20  (from fold line  16  to outer edge  34 ) in blank  10  corresponds to the height of the side walls of the erected container in FIG. 2. Ideally this height of side panel is the same as the height of the end panel  18 . In the present example the height is 4¼ inches.  
         [0027]    The container is erected either manually or by an automated machine. Generally it is done with an automated machine, wherein bottom panel  12  is pushed downward, forcing end  18  and  20  to simultaneously fold upwards along fold lines  14  and  16 , respectively. End flaps  30  are then folded along fold lines  28  and are adhered to the outer surface of side panels  20  with a hot melt adhesive. When this happens, bottom edge  50  aligns with fold line  16 , pulling down end flap  30  and end flap  50  at an angle, thereby causing a taper in end panel  50 . The taper of the end panel may be slight, preferably between 1-5°, although this can vary widely within the scope of the invention depending on the angle of divergence of bottom edge  50 . The results of the taper is an angle less than 90° between bottom panel  12  and end panel  50 . The corresponding angle of the stacking tabs extending co-planar to the end panels vs. the bottom panel is therefore also less than 90°. In alternate embodiments, the end flaps can be adhere to the outer surface with another means, such as staples.  
         [0028]    [0028]FIG. 2 shows an alternate embodiment, wherein the side walls and the corresponding stacking tabs on the side walls are tapered. Bottom panel  68  is a generally rectangular panel bordered on four sides by end fold lines  98  and side fold lines  100 . End panels  72  and side panels  78  and  94  are foldably connected to base panel  68  along fold lines  98 ,  100  and  100 , respectively. Further, female notch members  76  partially extend into the base panel, traversing fold line  98 , and female slot members  102  are cut out of base panel and border fold lines  100 .  
         [0029]    Side panel  78  is a generally rectangular panel that corresponds to at least one side wall when the container is fully erected. Accordingly, the length of side panels  78  in blank  70  corresponds to the height of the side wall when the container is erected. In the present example, the length of the side panel is 9{fraction (11/16)} inches, but the exact length can vary widely within the spirit of the invention. Each side panel  78  is bordered on four sides by an upper edge line  104 , lower fold line  100 , and two opposing side fold lines  106 . Side flaps  82  foldably attach to each side panel along fold lines  28 . One or multiple stacking tabs  80  extend outwardly from upper edge  104 , co-planar to side panel  78 .  
         [0030]    Side flaps  82  function in largely the same manner as end flaps  30  on blank  10  in FIG. 1. Flaps  82  are substantially rectangular panels wherein bottom edge  110  and top edge  112  diverges at slight angles from the side wall, thereby causing the end panel  78  and corresponding stacking tabs  80  to taper when the panel is erected. Like flap  30 , bottom edge  110  extends generally in the same lateral plane as fold line  100 , except it diverges with a slight angle toward the top edge  112 . Likewise, top edge  112  exists largely in the same plane as upper edge line  104 , except with a divergent angle away from bottom edge  110 . The angle of divergence of the top edge is ideally the same as the angle of divergence of the bottom edge. This allows top edges  112  and  80  to create a flat, even top corner even when the side wall is tapered.  
         [0031]    In FIG. 2, only one of the side walls includes stacking tabs integrally attached, extending co-planar from the top edge of the wall. The other side wall, side wall  94 , foldably connects to the base panel along fold line  100  and opposite to end flap  78 . Side wall  94  is a generally rectangular shape with a large, trapezoidal recess  116  providing side view visibility and breathing holes for the items held within. Side flaps  96 , which are foldably connected to side flaps  94  along fold lines  108 , function in the same way as side flaps  82 . However, the flaps need not be identical. For example, in FIG. 2, the angle of divergence of bottom line  118  is greater than the divergence of bottom line  110 . As a result, side panel  94  has a more severe taper than side wall  78 . However, the angle of divergence of bottom  118  can vary widely within the spirit of the invention. Further, end wall  94  may be replaced by an end wall substantially similar in configuration to end wall  78 . For example, side wall  94  may have stacking tabs extending co-planar from the top edge of the wall instead of recess  116 .  
         [0032]    End panels  72  are generally rectangular panels that correspond to the end walls when the container is fully erected. Accordingly, the length of end panels  72  corresponds to the height of the end walls of the erected container. Ideally the height of side panel is similar to that of side walls  78  and  94 , although not necessarily identical. In the present example, the height is 9¾ inches. End panels  72  further comprise stacking tabs  74  extending co-planar from the end wall. The bottom of end panel  72  contains notches  76 , proportioned and positioned to engage and hold a stacking tab  74  of an adjacently stacked container. Neither end walls  72  nor the stacking tabs  74  are tapered.  
         [0033]    Females member locks  102  in FIG. 2 are scored, cut and function much the same way as slots  24  in FIG. 1. Each lock  102  has a cut slot  88  coupled with a flap  84 , wherein the slot is designed engage and secure tapered stacking tabs  80  of an adjacent container. To fully engage and accept a tapered stacking tab, flap  84  has the ability to bend upwards along the back cut line  86 . Contact edge  90  engages and holds secure stacking tabs  52  by rubbing against the tabs, and holding it secure with a frictional force. In the present example, contact edge  90  is tongue shaped, with the center of the edge being closer to fold line  100  than the sides of the edge. Alternatively, the contact edge may run parallel to the fold line, like locks  24  in FIG. 1. Other embodiments include extensions of other shapes and arrangements, such as a concave arc.  
         [0034]    Locks can be scored on one or both opposing sides of bottom panel  68 . FIG. 2 shows locks scored on opposing sides of the bottom panel. This is advantageous by allowing one container to stack on top of another even if the north-south orientation of a container is opposite from the adjacent container.  
         [0035]    End wall  78  may further include a crushed area  92  that borders cut out slot  88  across fold line  100 , wherein the crushed area comprises a section of the end wall that is pressed to a point wherein the thickness of the crushed area is less than the thickness of the side wall. The crushed area allows easier access of a stacking tab  80  into a slot  102  of an adjacently stacked container in embodiments where the taper of end wall  80  is very slight.  
         [0036]    Blank  70  is preferably erected in the same manner as blank  10 , through use of an automated machine that folds end panels  72  and side panels  78  and  94  upwards along fold lines, and adhering side panels  82  and  96  to the outer side of end panels  72  with a hot melt adhesive or other adhering means, such that edge  110  aligns with fold line  98 , causing a taper in the side walls.  
         [0037]    A third embodiment of the container is seen in FIG. 3. Here, a reinforcement flap is added to the top of side wall  128  to reinforce the stacking tabs and to create a larger top ledge on the top edge of the side walls. The reinforcement flap is a long, thin band of flexible material similar in width to the side walls, but considerably shorter in length than the side walls. The flap further comprises small flaps  144  foldably attached along opposing fold lines  164  on the flaps opposing shorter ends, and at least one tab reinforcement  142  integrally attached to the flap along one of the longer ends.  
         [0038]    Side wall  128  of FIG. 3 is similar to side wall  78  in FIG. 2. Specifically, tapered side wall  128  is bordered by a lower fold line  124 , two opposing end fold lines  136 , and an upper top edge  160 . Stacking tabs  140  extend outward from edge  160 , co-planar to end wall  128 . Side flaps  134  are foldably attached to side panel  128  along fold lines  136 , and have a bottom edge  130  that diverges from fold line  124  and a top edge  166  that diverges from upper edge  160 , wherein the angles of divergence is the same for top edge  166  and bottom edge  150 . In the embodiment shown, edge  150  has an increased taper over edge  50  and  110  of the prior embodiments. The amount of the increased taper, if any, can vary widely in the spirit of the invention.  
         [0039]    Reinforcement tabs  142  foldably connect to the top edge of stacking tabs  140  along fold line  162 . When the container is erected, end panel  128  is folded upwards along fold line  124 . Reinforcement flap  138  is then folded downward along fold line  162  until the face of the reinforcement flap is flush against the top of the inner surface of panel  128 , as seen in FIG. 4. Small flaps  144  then partially fold along fold line  164  so that the small flap is diagonal to the corner of end flap  134  and side wall  136 . The diagonal corner creates an upper ledge that increases the sturdiness of a container stack by preventing a container higher in the stack from falling downward into a lower container.  
         [0040]    The combination of stacking tab  140  and reinforcement tab  142  is a larger, thicker tapered stacking tab extending from the top side of the tapered side wall. To account for this additional thickness, the cut open slot  148  of lock  146  is wider to accommodate the larger, reinforced tab.  
         [0041]    The remainder of the container blank in FIG. 3 is similar in function to that of FIG. 2. Additionally, however, side wall  130  may have one or more top reinforcement flaps  156 , wherein flap  156  is attached to wall  130  along perforated fold line  172 , and can fold over and lie flush against the inner surface of wall  130 . Top reinforcement flap  156  further has corner reinforcement  158  foldably attached along fold line  174 . The corner reinforcement folds along line  174  so that it is diagonal to the corner of side wall  130  and end wall  126 , mirroring small flaps  144 . The diagonal corner creates an upper ledge that increases the sturdiness of stacking container by preventing a container higher in the stack from falling downward into a lower container.  
         [0042]    Side wall  130  further has side flaps  154  with a divergent bottom edge  176  and a diverging top edge  178 , resulting in a taper of side wall  130  when the container is erected. Side flaps  154  may also contain lengthened area  170 , which is a small extension of paperboard extending from top edge  178 , coplanar to flap  154 . The lengthened area  170  fits into corresponding notch  168  of an adjacently stacked container, as seen in FIG. 4. The notch is a recess in flap  154  positioned along bottom edge  176 , to engage and secure the lengthened area  170 .  
         [0043]    In alternative embodiments, the side wall  130  may be replaced with a side wall similar to the side wall  128  of FIG. 3 or side wall  78  or  94  of FIG. 2, wherein the side walls are tapered and may have tapered stacking tabs extending co-planar therefrom, wherein the tabs fit into slots cut from the bottom panel, and not the side wall, of an adjacent stacking container.  
         [0044]    Although the invention has been described with reference to preferred embodiments, it will be appreciated by one of ordinary skill in the art that numerous modifications are possible in light of the above disclosure. For example, the stacking tabs extending co-planar from the tapered end walls and side walls may be different shapes than the tabs depicted in the drawings without departing from the spirit of the invention. All such variations and modifications are intended to be within the scope and spirit of the invention as defined in the claims appended hereto.