Abstract:
In a system and method for stabilizing a first stack of upper and lower shipping containers with respect to a second stack of upper and lower shipping containers, inter-box connectors are provided for connecting the upper and lower containers of each stack. A container bridging stabilizer is provided which surrounds two of the adjacent inter-box connectors where the two lower containers are laterally adjacent each other to laterally link the inter-box connectors and their respective lower containers together. The container bridging stabilizer laterally stabilizes the first and second stacks with respect to each other.

Description:
BACKGROUND OF THE INVENTION 
   Freight shipping containers are well known, and are available, for example, in lengths such as 20′, 40′, and 48′. Rail cars known as “well” cars have a bottom well which receives either a single long container or two short containers, such as 20′ containers arranged end-to-end. 
   It is also known to provide on top of two end-to-end 20 foot containers in a well car a 40′ or 48′ foot container stacked on top, which is linked to the two lower level 20′ containers by what are known as semi-automatic inter-box connectors. A number of companies manufacture such semiautomatic inter-box connectors, including Martec, International of South Plainfield, N.J. When such a single long container is provided on top of the two 20′ containers, stability is achieved since the upper container straddles, and is connected to, both of the lower 20′ containers. 
   For connecting the upper container to the two lower containers, it is known to provide top and bottom corner castings at, or near, the upper and lower four corners of the containers. These castings provide a locking surface containing an oval cutout. The semi-automatic inter-box connectors are arranged between the top and bottom container corner castings and have rotatable locking elements received in the respective oval holes of the top and bottom corner castings, so as to lock the containers together in a vertical configuration. 
   When two 20′ containers are placed in the well car at the bottom level, although it would be desirable to place a 40′ or 48′ container at the top level, such a container may not be readily available at the loading site. Although it would be desirable to place two additional 20′ containers at a top level and stacked on top of the two lower level 20′ containers, even with the use of the semi-automatic inter-box connectors, lateral stability of the respective stacks would be a major problem which would preclude such an arrangement. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide sufficient stability to allow two smaller-sized containers to be stacked on top of two similar smaller-sized lower containers. 
   According to the invention, a system and method are provided for stabilizing a first stack of upper and lower shipping containers with respect to a second stack of upper and lower shipping containers. Respective inter-box connectors are provided for connecting the upper and lower containers of each stack. At least one container bridging stabilizer is placed around two adjacent inter-box connectors to laterally link them and their respective lower containers together. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view showing four similar relatively short containers stacked on a rail well car, and employing both semi-automatic inter-box connectors and bridging stabilizers to provide overall stability to the stacked arrangement; 
       FIG. 2  is a top view taken along section line II—II of  FIG. 1 ; 
       FIG. 3  is a fragmentary top view of adjacent top corner castings of two adjacent end-to-end lower shipping containers prior to introduction of semi-automatic inter-box connectors; 
       FIG. 4  is a side view of a central junction location for four adjacent containers as shown in  FIG. 1  showing the respective adjacent upper and lower corner castings in fragmentary view, but without the presence of the semi-automatic inter-box connectors and corresponding bridging stabilizers for clarity; 
       FIG. 5  is a perspective view of two inter-box connectors surrounded and linked by a respective container bridging stabilizer at adjacent corners of two lower-level end-to-end containers prior to stacking of two additional similarly sized containers at a top level; 
       FIG. 6  is a side view of two inter-box connectors mounted in four respective corner castings of four respective containers and wherein a container bridging stabilizer surrounds the two inter-box connectors; 
       FIG. 7  is a top view of the arrangement shown in  FIG. 6 ; 
       FIG. 8  is a plan view of the container bridging stabilizer; 
       FIG. 9  is a side view of the container bridging stabilizer; 
       FIG. 10  is a side view showing a container spreader tool for positioning the containers prior to introduction of inter-box connectors and a respective container bridging stabilizer; and 
       FIG. 11  is a bottom view looking up at the container spreader tool shown in  FIG. 10 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and/or method, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to one skilled in the art to which the invention relates. 
   As shown in  FIG. 1 , an arrangement  10  of four containers are provided in a well car  11  having a well  12  for receiving two bottom containers  13 ,  14 . Two top containers  15  and  16  at an upper level are stacked on top of the respective lower containers  13  and  14 . The containers may all be similarly sizes, such as 20′ containers, for example. 
   In  FIG. 2 , a plan view along section line II—II illustrates a location of semi-automatic inter-box connectors  17 ,  18 ,  19 ,  20 ,  21 ,  22 ,  23 , and  24  joining the respective containers  13  and  15 , and  14  and  16 , together. Additionally, container bridging stabilizers  25  and  26  comprising stabilizing frames are provided surrounding the respective inter-box connectors  19 ,  21  and  20 ,  22 . 
   As shown in  FIG. 3 , a fragmentary view is illustrated from the top of an upper corner casting  13 A of container  13  and an upper corner casting  14 A of container  14 . These corner castings have respective oval locking apertures or holes  13 B and  14 B in a locking plate or surface  13 C,  14 C. 
   As shown in  FIG. 4 , when viewed from the side at the middle of the container arrangement shown at  10  in  FIG. 1 , the four respective corner castings  13 A,  14 A,  15 A, and  16 A of the respective containers  13 ,  14 ,  15  and  16  are positioned adjacent each other. Side ovals  133 B,  144 B,  155 B, and  166 B are provided in corner casting side surfaces  133 D,  144 D,  155 D,  166 D. The inter-box connectors are not shown in this view for clarity. It can also be seen how the oval locking holes  13 B,  14 B,  15 B, and  16 B are positioned oppositely facing each other. 
   In the perspective view of  FIG. 5 , two semi-automatic inter-box connectors, for example of the Martec International of South Plainfield, N.J., are provided as shown at  20  and  22 . These inter-box connectors are locked into respective corner castings  13 A,  14 A of containers  13 ,  14 . The two inter-box connectors are surrounded by the respective container bridging stabilizer  26 . As may be appreciated, the inter-box connectors attach the containers stacked above one another and the container bridging stabilizer connects and stabilizes the two adjacent stacks formed of respective containers  13 , 15  and  14 , 16  with respect to each other. 
   With reference to  FIG. 6 , details of the inter-box connectors and respective container bridging stabilizer may be seen. 
   The prior art inter-box connector  20  is formed of a centrally located inter-box connector body  20 A having a lower rotatable locking element  20 B and an upper rotating locking element  20 C which are actuated by locking pull cord  20 D. These fit in the respective corner casting ovals, and are rotated to lock to the locking corner casting locking surface  15 C or  13 C, as the case may be. 
   The inter-box connector body  20 A has separating flanges  20 E and  20 F, so that the top shipping container rests on the flanges and is thus spaced from the bottom shipping container. Separating flanges  20 E,  20 F (also see  FIG. 7 ) have positioned therebetween a raised portion  20 G of the inter-box connector body  20 A. 
   The container bridging stabilizer  26  surrounds and links the two inter-box connectors  20 ,  22  as shown in  FIGS. 6 and 7 . 
   Details of the container bridging stabilizer are also clearly shown in the plan view of  FIG. 8  and the side view of  FIG. 9 . The container bridging stabilizer  26  has a stabilizing frame  27  with end interlocking surface  32 ,  28  which cooperate with locking protrusions  33 ,  37  to position the respective inter-box connectors  20 ,  22  at respective locking regions  34 ,  35 . A central access opening  36  is provided where the respective handles of the two inter-box connectors are situated. 
   A top container spacer  29  and a bottom container spacer  30  are provided as shown most clearly in  FIG. 9 . These have a width  100  corresponding to the container spacing. This container spacing is set by a container spreader tool described hereafter as shown in  FIGS. 10 and 11 . The container spacing not only insures access to the inter-box connector operating handles, but also allows placement of the container bridging stabilizer around the correctly spaced inter-box connectors. 
   The thickness  101  of the stabilizing frame  27  is equal to or somewhat less than a thickness of the separating flanges  20 D,  20 E of the inter-box connectors. Thus the container bridging stabilizer will then fit between the adjacent top and bottom containers. 
   The top and bottom container spacers  29  and  30  have respective flat surfaces  29 A,  30 A and beveled side portions  29 B,  29 C,  30 B and  30 C. 
   As shown in  FIG. 10 , to ensure proper spacing of the containers prior to insertion of the inter-box connectors and corresponding bridging stabilizer, a container spreader tool  37  is provided having an operating handle  38  connected by a ratchet housing  39  containing a ratchet  40  which drives respective adjusting screws  41 ,  42  connected to respective engagement members  43  and  45  having respective engagement lips  44  and  46 . These are received in the side ovals  133 B,  144 B of the corner castings as illustrated. By moving the handle  38 , the ratchet mechanism decreases or increases the spacing between the engagement members  43  and  45 . 
     FIG. 11  shows the bottom view looking up at the container spreader tool being received in the ovals  133 B,  144 B in the respective side surfaces  133 D,  144 D of the corner castings  13 A,  14 A. 
   Of course, in addition to use on rail well cars, the container bridging stabilizer may be used for stacking containers on other types of transport units such as trucks, ships or other transportation vehicles. 
   Although a particular type of inter-box connector from the prior art has been shown, the container bridging stabilizer may be used with other types of inter-box connectors and other types of containers having locking apertures of various shapes and sizes with different types of corner attachment apertures or mechanisms. Furthermore, the particular shape of the container bridging stabilizer may be varied to accommodate different types of inter-box connectors, different types of containers, and different types of corner attachment systems. 
   Although it is preferred to make the container bridging stabilizer of steel, other types of materials may also be employed. 
   While a preferred embodiment has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention both now or in the future are desired to be protected.