Abstract:
A stackable container includes top and bottom surfaces; opposing side surfaces; opposing end surfaces; and interlock mechanisms on at least one of 1) the top and bottom surfaces, 2) the opposing side surfaces and 3) the opposing end surfaces. Because of the interlock mechanisms, a plurality of the containers may be stacked and shipped, such as on a pallet, without the use of support bands.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates in general to packaging and in particular to the stacking of containers. 
     Containers are often stacked on pallets for shipping. After the pallet is completely loaded with containers, the containers are typically secured to the pallet with bands or straps. When stacking the containers on the pallet, care must be taken to prevent the stacked containers from shifting or falling over. To unload the containers from the pallet, the bands are cut and the containers removed. Because of movement of the containers during shipping, sometimes the containers will undesirably “unstack” themselves when the bands are removed. Particularly for fragile containers or fragile container contents, even a short fall to the ground may cause damage. 
     Another problem with packaging bands occurs when only a portion of a pallet of containers is desired at a location. After the desired number of containers are removed from the pallet, the containers remaining on the pallet must be restacked and re-banded for shipping. There is a need for a packaging solution that overcomes the problems associated with banding containers together. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide interlocking containers. 
     It is another object of the invention to provide interlocking containers that may be stacked and shipped without using conventional bands. 
     One aspect of the invention is a container comprising top and bottom surfaces; opposing side surfaces; opposing end surfaces; and interlock mechanisms on at least one of 1) the top and bottom surfaces, 2) the opposing side surfaces and 3) the opposing end surfaces. 
     In one embodiment, the interlock mechanisms comprise side to side interlock mechanisms comprising a right side interlock and a left side interlock, the right side interlock comprising a generally V-shaped angle having a first portion that extends out and away from a side surface and a second portion that extends upward and substantially parallel to the side surface, the left side interlock comprising a generally V-shaped angle having a first portion that extends out and away from an opposing side surface and a second portion that extends downward and substantially parallel to the opposing side surface. 
     In another embodiment, the interlock mechanisms comprise end to end interlock mechanisms comprising a knob on a rear end of the container and an opening in a plate on the front end of the container. The plate may comprise a component of a closure for the container. The opening in the plate may be generally V-shaped and open downwardly. 
     In a further embodiment of the invention, the interlock mechanisms comprise top to bottom interlock mechanisms comprising front and rear tabs on the top surface of the container and a bottom assembly attached to the bottom surface of the container. The bottom assembly may include a peripheral skirt comprising a front lip having a generally flat surface substantially parallel to the bottom surface of the container. The front tab includes a generally flat surface substantially parallel to the top surface of the container. 
     The bottom assembly includes at a rear end thereof a slider assembly comprising a handle disposed on an exterior of the bottom assembly and a slider attached to the handle and slidable through a slot in the peripheral skirt. The slider assembly includes a spring for biasing the slider assembly towards an interior of the bottom assembly. The slider includes a striker and the rear tab includes a striker plate operable to latch against the striker. 
     Another aspect of the invention is a pallet having a plurality of top to bottom interlock mechanisms comprising front and rear tabs that are substantially the same as the front and rear tabs on the top surface of the containers. The front and rear tabs on the pallet interlock with the bottom assemblies of the bottom row of containers on the pallet. 
     The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals. 
         FIG. 1  is a perspective view of one embodiment of containers in accordance with the invention. 
         FIG. 2  is a perspective view of the containers of  FIG. 1  taken from another angle. 
         FIG. 3  is a perspective view of a container. 
         FIG. 4  is a perspective view of the container of  FIG. 3  taken from another angle. 
         FIG. 5  is a perspective view of a bottom assembly. 
         FIG. 6  shows one portion of the connection between the bottom assembly of one container and the top of another container. 
         FIG. 7  is a perspective view of the bottom assembly attached to its container. 
         FIG. 8  is an enlarged view of another portion of the connection between the bottom assembly of one container and the top of another container. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention includes a band-free packaging apparatus and method. The apparatus comprises a container having features for interlocking it with another, similar container. While the container shown in the Figures is generally rectangular, the invention is not limited to the specific geometry of a rectangular container. The inventive container includes one or more of lateral interlocking features, forward/backward interlocking features and top/bottom interlocking features. 
       FIG. 1  is a perspective view of one embodiment of containers  10  in accordance with the invention.  FIG. 2  is a perspective view of the containers  10  of  FIG. 1  taken from another angle.  FIGS. 1 and 2  show five containers  10 . Each container  10  comprises top and bottom surfaces  16 ,  18 ; opposing side surfaces  20 ,  22  and opposing end surfaces  24 ,  26 . As viewed in  FIG. 1 , side surface  20  is the right side surface, side surface  22  is the left side surface, end surface  24  is the front end surface and end surface  26  is the rear end surface. The use of the terms right, left, front and rear is for clarity in describing the invention and is not meant to limit the location or orientation of the features of the invention. 
     Top surface  16  functions as a lid that is hinged at  30  to the rear surface  26  and held closed by closure  32  on front end  24 . Closure  32  is known, particularly for military ammunition containers, and includes a wire or rod member  34  that fits in a rounded lip  36  attached to top surface  16 . Top surface  16  includes a collapsible handle  38  thereon. The type of lid  36 , lid closure  32  and handle  38  that are shown are exemplary only. Other types of lids, lid closures and handles may be used with container  10 . 
     Right side  20  ( FIG. 1 ) includes a side interlock  12  that mates with side interlock  14  on the left side  22  ( FIG. 2 ) of an adjacent container.  FIGS. 3 and 4  are perspective views of container  10  that show the side interlocks  12 ,  14 . Interlock  12  comprises a generally V-shaped angle having a first portion  42  that extends out and away from side  20  and a second portion  44  that extends upward and substantially parallel to side  20 . One way of making interlock  12  is to stamp and bend it from a piece of V-shaped flat stock. In that case, a base portion  46  may be attached to side  20  by, for example, welding. However, the edge of first portion  42  could be attached directly to side  20  without the need for base portion  46 . Container  10  and its interlocks may comprise metal, plastics, or other suitable materials. 
     Left side  22  ( FIG. 4 ) includes a side interlock  14  comprising a generally V-shaped angle having a first portion  50  that extends out and away from side  20  and a second portion  52  that extends downward and substantially parallel to side  20 . Interlock  14  may be fabricated similarly to interlock  12 . Interlocks  12 ,  14  work as follows. A first container  10  is placed in the position shown in  FIG. 3 . A second container  10  is positioned above and to the side of first container  10  such that interlock  14  of second container  10  is aligned with and vertically above interlock  12  of first container  10 . As second container  10  is lowered, portion  44  of interlock  12  slides underneath portion  52  of interlock  14 . Additional containers are interlocked in a similar manner. Any lateral forces on the containers will be resisted by the abutting surfaces of portions  44  and  52 . 
     Referring again to  FIGS. 3 and 4 , container  10  has opposing front and rear end surfaces  24 ,  26 . comprising end to end interlocking mechanisms. Front end  24  ( FIG. 3 ) includes the closure  32  having a generally flat portion  60 . Flat portion  60  includes an opening  62  comprising a circular portion  64  and a V-shaped portion  66 . The V-shaped portion  66  opens towards the bottom of the container  10 . Flat portion  60  and opening  62  comprise one of the end to end interlocks. Rear end  26  ( FIG. 4 ) includes a knob  54  having a stem  56  attached to rear end  26  and a head  58  on the end of the stem  56 . Knob  54  comprises the other end to end interlock. Ends of adjacent containers  10  are locked by sliding the stem  56  of knob  54  of one container  10  into the opening  62  in an adjacent container  10 . Any end to end forces on the containers  10  will be resisted by the head  58  of knob  54  bearing against flat portion  60  of closure  32 . 
     The top to bottom interlocking mechanisms are located on the top surface  16  and bottom surface  18  of container  10 . As seen in  FIG. 4 , the top surface  16  includes upwardly projecting rear and front tabs  68 ,  70 . When the container  10  includes a collapsible handle  38  as shown in  FIG. 4 , tabs  68 ,  70  may be conveniently fabricated to include loops  72 . Loops  72  allow the rings  74  of handle  38  to move as the handle is raised and lowered. However, the loops  72  are not required for the top to bottom interlocking mechanism and may be omitted if another type of handle is used. The front and rear tabs  70 ,  68  comprise one portion of the top to bottom interlocking mechanisms. 
     The other portion of the top to bottom interlocking mechanism, as seen in  FIG. 4 , comprises a bottom assembly  76  attached to the bottom surface  18  of container  10 . Bottom assembly  76  includes a peripheral skirt  78 . Referring now to  FIGS. 1 and 2 , the topmost container  10  includes on its top surface a bottom assembly  76 . Normally, bottom assembly  76  is attached to the bottom surface of a container  10  via the flat border surface  80 . However, for clarity, only a bottom assembly  76  is shown on top of the topmost container in  FIGS. 1 and 2 . Inside of border surface  80 , the bottom assembly  76  is open and the front and rear tabs  70 ,  68  of the container below are visible. 
       FIG. 5  is a perspective view of a bottom assembly  76  having a front lip  86 . Front lip  86  mates with front tab  70  ( FIG. 4 ) on the top of another container.  FIG. 6  shows the connection between the front lip  86  of one container (the top or upper container) and the front tab  70  of another container (the bottom or lower container). Front tab  70  includes a generally flat surface  90  substantially parallel to the top  16  of its container  10 . Front lip  86  includes a generally flat surface  88  substantially parallel to the bottom (not shown in  FIG. 6 ) of its container  10 . When the front lip  86  of the upper container  10  is slipped under the front tab  70  of the lower container, the flat surfaces  88 ,  90  are adjacent each other and provide a bearing surface against forces tending to pull the upper container vertically away from the lower container. 
       FIG. 7  is a perspective view of the bottom assembly  76  of  FIG. 5  attached to its container  10 .  FIG. 8  is an enlarged view of a portion of the connection between the bottom assembly  76  of one container and the top of another container. Referring to  FIGS. 5 ,  7  and  8 , the bottom assembly  76  includes at a rear end thereof a slider assembly  92  comprising a handle  82  (best seen in  FIG. 4 ) disposed on an exterior of the bottom assembly  76  and a slider  94  attached to the handle  82  and slidable through a slot  96  in the peripheral skirt  78 . 
     The slider assembly  92  further includes a spring  98  for biasing the slider assembly  92  towards an interior of the bottom assembly  76 . A leaf-type spring  98  is shown in the Figs., but other types of springs may be used. The ends of spring  98  may be held in place with, for example, small protrusions  100  ( FIG. 5 ) formed on the interior of the peripheral skirt  78 . The sides of the spring are constrained by the slider  94  on one side and, for example, a pair of tabs  106  ( FIGS. 5 and 7 ) attached to the interior of the peripheral skirt  78 . 
     Slider  94  includes a striker  102  shown as a generally flat, horizontal surface. The rear tab  68  ( FIG. 8 ) includes a striker plate  104  shown as a generally flat surface angled at about forty-five degrees with respect to the striker  102 . In  FIG. 8 , the striker  102  is shown in a latched position beneath striker plate  104 . The top to bottom interlocking mechanism operates as follows. Two containers  10  are initially separated. One container  10  is placed over and aligned with another container  10  with the upper container angled downward from its rear end  26  to its front end  24 . The front lip  86  of the bottom assembly  76  of the upper container is guided below the front tab  70  of the lower container. The rear end  26  of the upper container is then lowered toward the lower container. 
     As the upper container is lowered, the striker  102  of the upper container will contact the striker plate  104  of the lower container. Further lowering of the upper container causes the striker  102  to move down the angled surface of the striker plate  104 . The spring  98  keeps the striker  102  biased against the striker plate  104 . When the striker  102  reaches the end of striker plate  104 , the striker  102  is forced by spring  98  to slide under striker plate  104 , thereby latching the upper container to the lower container. To unlatch the containers, one pulls on handle  82  to slide the striker  102  away from and free of striker plate  104 . The upper container may then be lifted off the lower container. The spring-biased striker  102  and striker plate  104  operate much like a door latch, wherein the upper container is “snapped on” to the container below it. 
     A plurality of the containers  10  may be stacked and interlocked on a pallet. The integrity of the entire pallet (without the need for banding) is obtained by the interaction of neighboring containers  10  as a complete system. The top to bottom interlocking connection of an upper container to a lower container forces the lateral (side to side) and forward/backward (end to end) interlocking features to remain firmly engaged. In essence, each additional container  10  added to the stack locks down the container  10  that was last added to the stack. In some embodiments, a “build order” for the containers  10  may be necessary. In those embodiments, the unstacking of the containers  10  is the reverse of the build order. 
     A further feature of the invention is a pallet having interlock mechanisms that engage the bottom row of containers  10 . The interlock mechanisms on the pallet may be similar to the upwardly projecting front and rear tabs  70 ,  68  located on the top surface of container  10  and shown in  FIG. 4 . A plurality of the tabs  70 ,  68  are positioned on and fixed to the pallet surface to interlock with the bottom assemblies  76  ( FIGS. 5-8 ) of the bottom row of containers  10 . 
     While the invention has been described with reference to certain preferred embodiments, numerous changes, alterations and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.