Patent Publication Number: US-2021188536-A1

Title: Apparatus for engaging and securing container corner fittings

Description:
INTRODUCTION 
     Aspects of the present disclosure relate to cargo container connection equipment, and in particular to apparatuses and methods for engaging and securing corner fittings found on cargo containers. 
     Cargo containers are moved about the world by various types of crafts, such as trucks, ships, trains, and aircraft. In order to facilitate shipment of goods in a global economy, standards for shipping containers have been developed to enable intermodal shipping. So-called “ISO” containers are containers with standardized outer dimensions as well as standardized connection point locations and hardware so that containers may reliably be carried from place to place by various types of crafts with complementary container connection equipment. 
     While standards have emerged for cargo containers, the connection equipment used for such cargo containers has generally gone without development. Conventional connection equipment is designed to stay affixed to a cargo container and whatever it is connected to, such as another container or a carrier vehicle. Conventional equipment therefore increases the container&#39;s tare weight at the expense of its net weight carrying capacity. Further, conventional connection equipment only works when containers are oriented precisely with respect connection equipment, which may require difficult and time-consuming manual manipulation of containers before shipment. 
     Accordingly, there is a need for improved apparatuses and methods for engaging and securing cargo containers. 
     BRIEF SUMMARY 
     Certain embodiments provide a method of securing containers, comprising: attaching a tool to a first corner fitting of a first container and a second corner fitting of a second container, wherein: the tool comprises: a first slideable portion comprising a first plurality of pins and a rack; and a second slideable portion slideably connected to the first slideable portion and comprising a second plurality of pins and a rotatable pinion in contact with the rack, and attaching the tool comprises: inserting the first plurality of pins on the first slidable portion into a first plurality of engagement recesses in the first corner fitting; and inserting the second plurality of pins on the second slideable portion into a second plurality of engagement recesses in the second corner fitting; applying a torque to the rotatable pinion in order to cause: the first slideable portion to apply a first force to the first corner fitting in a first direction and move the first container in the first direction; and the second slideable portion to apply a second force to the second container in a second direction, opposite the first direction, and move the second container in the second direction; and removing the tool from the first corner fitting and the second corner fitting after the first corner fitting is moved into engagement with the second corner fitting. 
     Further embodiments provide a method of securing containers, comprising: determining a first aperture geometry of an aperture of a first corner fitting; determining a second aperture geometry of an aperture of a second corner fitting; selecting a corner fitting clip based on the first aperture geometry and the second aperture geometry; and affixing the corner fitting clip to the aperture of the first corner fitting and the aperture of the second corner fitting. 
     Further embodiments provide a tool for manipulating containers, comprising: a first slideable portion comprising a first plurality of pins and a rack; and a second slideable portion slideably connected to the first slideable portion and comprising a second plurality of pins and a rotatable pinion in contact with the rack, wherein the first plurality of pins and the second plurality of pins are configured to engage with engagement recesses of a corner fitting. 
     The following description and the related drawings set forth in detail certain illustrative features of one or more embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended figures depict certain aspects of the one or more embodiments and are therefore not to be considered limiting of the scope of this disclosure. 
         FIGS. 1A and 1B  depict examples of corner fittings with surface connector arrangements. 
         FIGS. 2A - 2 D 2  depict an example of using improved tools for engaging and manipulating containers including corner fittings. 
         FIGS. 3A-3B  depict alternative arrangements of tools for engaging and manipulating containers including corner fittings. 
         FIG. 4  depicts an example of a clip that secures two container corner fittings to each other. 
       FIGS.  5 A 1 - 5 C 2  depict various embodiments of additional hardware for retaining corner fitting clips. 
         FIGS. 6A - 6 C 4  depict various geometries for the container corner fitting clips. 
         FIGS. 7A-7C  depict modular, two-part corner fitting clips. 
       FIGS.  8 A 1 - 8 B 4  depict examples of clip and corner fitting features for further retaining clips. 
         FIGS. 9A-9E  depict an example container clip with an integral retention mechanism. 
         FIG. 10  depicts an example method for connecting containers. 
         FIG. 11  depicts an example method  1100  of securing containers. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the drawings. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
     DETAILED DESCRIPTION 
     Aspects of the present disclosure provide apparatuses and methods for engaging and securing corner fittings found on cargo containers. 
     Cargo carrying crafts, such as trucks, ships, trains, and aircraft move a great amount of cargo around the world. In order to do so efficiently, standardized container sizes and fittings have emerged to allow for efficient intermodal shipping. 
     Conventional equipment for connecting containers to container as well as containers to carriers (e.g., a truck, ship, train, or aircraft) has also been developed. For example, various types of ISO-compatible “twist-locks” are available for connecting containers with ISO-standard fittings (e.g., corner fittings). However, such conventional connection equipment is not intended to be used with containers that are arranged wall-to-wall with no significant gap between the containers. Rather, ISO-compatible connection equipment tends to be based on multiple inch gaps (e.g., 3″ in the horizontal direction and 1″ in the vertical direction) between containers when arranged for connection. Further, conventional equipment tends to be heavy, expensive, and finicky to use. For example, a conventional twist-lock requires precise alignment of the fitting with the twist lock for proper engagement. When such connection equipment is being used with large containers, such as ISO-standard 20-foot and 40-foot shipping containers, moving the container into a particular alignment is difficult because of the significant weight of such containers. The heavy weight of such containers results in very heavy weight for conventional connection equipment, such as ISO-compatible twist-locks. And because conventional connection equipment is configured to stay attached to the container, it increases the tare weight of the container to the detriment of the container&#39;s net weight carrying capacity. Further, in some cases, conventional connection equipment includes additional material to assist in aligning connections, but because this material travels with the connection equipment, it exacerbates the weight problem. 
     To overcome the limitations of conventional connection equipment, embodiments described herein separate the tasks of engaging and securing corner fittings. In other words, instead of having one mechanism to both engage the corner fittings and also secure them, such as a conventional twist-lock, embodiments described herein include separate aspects for engaging and securing container corner fittings that include surface connector arrangements. 
     Container Corner Fittings with Surface Connector Arrangements 
     Containers corner fitting described herein may utilize surface connector arrangements, which allow for direct interface between corner fittings of adjacent containers. 
     Surface connector arrangements on corner fittings, and on other container surfaces, may include patterns of connector elements. Patterns of connector elements may comprise multiple types of interlocking connector elements. For example, a first type of connector element (e.g., a “male” connector element) may comprise a protrusion, projection, pad or the like configured to fit within a recess of a second type of connector element (e.g., a “female” connector element). Connector elements may be formed in many shapes. 
     Corner fittings are different from corner-mounted surface connectors in that corner fittings are generally independent three-dimensional structures having their own interior volume that may be joined with, attached to, or made integral with a modular container, while corner-mounted surface connectors are generally joined with, attached to, or made integral with a surface of a modular container, but do not include their own interior volume. 
     In the examples depicted herein, corner fittings are depicted generally in a plan view with one face showing, but note that corner fittings are generally three dimensional, and may have multiple faces, such as six faces for rectangular cuboid shapes. The faces of a corner fitting are generally joined by edges. Because corner fittings may be designed to be permanently affixed to a container, such as welded to a container, some surfaces and edges may include surface connector elements and some may not. For example, internal faces (i.e., those pointing inward toward the container and not outward), may not include surface connector elements because they would not be able to engage (or interface) with other surface connector elements on other containers. Thus, as depicted in the following examples of corner fittings, certain edges that do not show protruding surface connector elements may be located on the inward-facing faces of the corner fittings. 
     Some arrangements of connector elements may be considered “passive” or “one-way” in that all of the connector elements are of a single type. For example, an arrangement may include all female type recesses. Such an arrangements may be intended to have other surface connectors attached to it. 
     Some arrangements of connector elements may be considered “active” or “two-way” in that its connector elements are of multiple types, such as a first type (e.g., protrusions) and a second type (e.g., recesses). 
     Some arrangements of connector elements may include fewer connector elements of the first type (protrusions) than of the second type (recesses). Other arrangements of connector elements could have more connector elements of the first type (protrusions) than the second type (recesses). However, in order to make sure that the arrangements could always interface correctly (e.g., where a protrusion has no matching recess with which to interface), the protrusions may be made spring-loaded. 
       FIGS. 1A and 1B  depict examples of a nominal 6-inch corner fitting with nominal 2-inch surface connector arrangements. 
       FIG. 1A  depicts a left-side corner fitting  100 , which includes 2-inch nominal (1.993 inch actual) surface connector arrangements  102 . In this embodiment, the surface connector arrangements are rotationally symmetric about the center of each full arrangement, which means each surface connector arrangement  102  presents the same pattern of connector elements when rotated by any 90 degree increment. For example, each surface connector arrangement can be divided into eight 45-degree wide zones starting from a vertical line (not depicted) emanating from the center of the arrangement to a top edge of the arrangement. Notably, some arrangements, such as  104 , are incomplete due to the aperture  106 . 
     Each of the surface connector arrangements  102  includes a pattern of connector elements of a first type and a second type, such as protrusions  112  and recesses  114 . Notably, some of the surface connector arrangements (e.g.,  104 ) have incomplete patterns of surface connectors due to the aperture  106 . 
     In this embodiment, the center of aperture  106  is offset 3.379 inches from two sides (or edges) of corner fitting  100  to enable compatibility with existing ISO corner fitting hole-to-corner fitting hole dimensions. Specifically, in this example, the center of aperture  106  is 3.379 inches from a first side (or edge) located along the right side of corner fitting  100 , and a second side (or edge) located along the bottom side of corner fitting  100 . Further, in this embodiment, aperture  106  is 2.5 inches in diameter. 
     In this embodiment, the surface connector arrangements each have centered engagement recesses  108  (or apertures) that allow for interfacing with ancillary equipment, such as the engagement and manipulation equipment described below with respect to  FIGS. 2A-3B . In this embodiment, each engagement recess  108  has a 0.375-inch diameter and is arranged in a grid pattern, spaced from adjacent recesses by a 1.993-inch spacing (e.g.,  110 ). Note, however, that in other embodiments, the engagement recesses  108  may be different diameters and arranged in different patterns. 
     Further in this embodiment, left side corner fitting  100  has a first exterior dimension of 5.983 inches in height and second exterior dimension of 5.983 inches in width. In some embodiments, left side corner fitting  100  also has a third exterior dimension of 5.983 inches in depth. 
       FIG. 1B  depicts a right-side corner fitting  150 , which is a mirror of the left-side corner fitting in  FIG. 1A . 
       FIGS. 2A - 2 D 2  depict an example of using improved tools for engaging and manipulating containers including corner fittings, such as described with respect to  FIGS. 1A-1B . 
       FIG. 2A  depicts two containers,  200 A and  200 B, each comprising a corner fitting with surface connector arrangements  202 A and  202 B, in an unconnected and adjacent arrangement. Containers  200 A and  200 B may be many sizes, including for example, nominally 12-inches, 18-inches, 24-inches, 32, inches, 48-inches, 64-inches, 96 inches, in the length, width, and/or height directions, and even longer in the length direction. However, in  FIGS. 2A-2C  and following figures, only the portions of the containers  200 A and  200 B adjacent to the corner fittings  202 A and  202 B are shown for clarity. 
     FIGS.  2 B 1  and  2 B 2  depict a tool  204  comprising two slideable portions, which are plates  206 A and  206 B in this embodiment, and a movement mechanism, which in this embodiment includes a pinion (or gear)  208  and a rack (or gear track)  210 . 
     The two slideable plates  206 A and  206 B are slideably connected to each other such that each one can move relative to the other one in a motion plane while remaining rigidly connected to the other. 
     Each of the slideable plates  206 A and  206 B include pins (e.g.,  212 ) that are spaced to align with and engage the engagement recesses (e.g.,  214 ) in the corner fittings. Because plates  206 A and  206 B are slideable relative to each other, they can be easily aligned with the engagement recesses  214  in corner fittings  202 A and  202 B. 
     In this embodiment, the pins  212  have a diameter of approximately 0.375-inch to match with engagement recesses  214 , however, in some embodiments the pin diameter, or a portion thereof, may be made slightly smaller for easier engagement. For example, pins  212  may have a slight draft to make it easier for pins  212  to enter engagement recesses  214 . Similarly, engagement recesses  214  may have a chamfer for the same purpose. 
     Notably, a 0.375-inch pin with 95 ksi shear stress can carry 10,492 pounds. Thus, with three pins  212  engaged with three engagement recesses  214 , there is an approximately 31,477 pound capacity, which is adequate to pull heavy containers into contact with each other. 
     Pinion  208  may be configured with a stud or other connection element so that an external tool, such as a socket wrench or an electric or air-powered tool, can be used to turn the pinion along rack  210  to cause one plate  206 A to slide relative to another plate  206 B. The combination of pinion  208  and rack  210  may referred to as a rack-and-pinion system. Notably, in this embodiment, the rack-and-pinion system comprises a single pinion  208 , but in other embodiments, if more mechanical advantage is required, a system of reducing pinions (or gears) can be provided. 
     As depicted in FIGS.  2 C 1  and  2 C 2 , the action of pinion  208  and rack  210  has brought the right-hand corner fittings  202 A and  202 B into contact with each other, which has also caused the surface connector arrangements of each corner fitting to engage with each other, thus providing a solid connection between containers  200 A and  200 B. 
     Further, pinion  208  and track  210  may be used to pre-stress joined corner fittings  202 A and  202 B to make it easier to attach other connection equipment, such as corner fitting clips (or other retainers), which are described in more detail below. 
     Pinion  208  and track  210  may be used in the opposite direction as well. For example, by reversing the direction of pinion  208 , containers  200 A and  200 B can be separated as well as the surface connector arrangements on their corner fittings. 
     As depicted in FIGS.  2 D 1  and  2 D 2 , tool  204  may be removed from containers  200 A and  200 B after they are brought together, which beneficially reduces the weight of the combined containers. Thus, unlike conventional connection equipment, tool  204  may be used to manipulate containers  200 A and  200 B into engagement with each other and then be removed before transport. However, it may be beneficial to leave tool  204  attached until all of the corner fittings between two containers have been securely attached to each other. 
       FIGS. 3A-3B  depict alternative arrangements of tool  204 . For example, in  FIG. 3A , tool  204  is used on a different set of engagement recesses as compared to  FIGS. 2B-2C . Further,  FIG. 3B  shows that multiple tools  204  can be used if more force is required. 
     Though not depicted in these figures, a similar tool with pins configured to engage all eight engagement recesses on each face of corner fittings  202 A and  202 B could be used if even more force is required, which may be the case if the cargo in the containers is very heavy. 
     Corner Fitting Clips for Securing Containers 
       FIG. 4  depicts an example of a clip  400  that secures two container corner fittings to each other, and thereby, two containers. 
     In this example, clip  400  is configured to slide into corner fittings  202 A and  202 B. In some embodiments, clip  400  may be retained by friction or engagement with a lip or other structure within apertures  402 A and  402 B. However, in other embodiments, as depicted below, additional hardware may be used to secure clip  400  to corner fittings  202 A and  202 B. 
     FIGS.  5 A 1 - 5 C 2  depict various embodiments of additional hardware for retaining corner fitting clips. In each figure, a cross-sectional view is aligned with a section cut view. 
     In FIGS.  5 A 1  and  5 A 2 , bolts  502  are used to ensure that clip  500  stays connected to corner fittings  202 A and  202 B. In some embodiments, locking hardware may be used to ensure that bolts  502  do not loosen due to vibration. For example, cotter pins may be used. 
     FIGS.  5 B 1  and  5 B 2  depict a similar arrangement to FIGS.  5 A 1  and  5 A 2 , but in this example, clip  500  fits into a recess in corner fittings  202 A and  202 B and similarly bolts  504  are countersunk into clip  500 . Thus, in this embodiment, clip  500  and its retaining hardware sit flush with the surfaces of containers  200 A and  200 B, which may be useful when many containers are stacked together. For example, recessed connection hardware will not obstruct corner fitting faces from fitting tightly against each other when containers are stacked side by side. Further, the recesses may allow for larger connection hardware to be used when needed for additional strength. Further yet, this allows clip  500  and its connection hardware to not protrude out of a 96-inch width envelope used by ISO-standard containers. 
     FIGS.  5 C 1  and  5 C 2  depicts another example where bolts  506  are relocated so that the recess or threaded hole is more interior to the corner fitting compared to that shown in FIG.  5 B 2 . As with the other embodiments, a slight protrusion of the head of each bolt can be easily locked with a cotter pin or other alternative locking method. 
       FIGS. 6A - 6 C 4  depict various geometries for the container corner fitting clips, which allow them to interface with many types of corner fitting apertures and in different directions. 
     For example,  FIG. 6A  depicts two clips  604 A and  604 B connected between corner fittings  602 A,  602 B, and  602 C of containers  600 A,  600 B, and  600 C. In this example, clips  604 A and  604 B have the same design as they are interfacing with the same aperture designs in each corner fitting. 
     Notably, clips  604 A and  604 B include angled portions (e.g.,  606 ) so that multiple clips can connect to an aperture (e.g.,  608 ) without interfering with each other. 
     In  FIG. 6B , two different types of clips  616  and  618  are depicted as attaching between three of the same type of corner fitting  612 A-C. In particular, this example shows how clips  616  and  618  may be used to interface with a bottom face of an ISO-compatible corner fitting, which is also compatible with conventional ISO twist-locks. 
     As depicted in this example, clips  616  and  618  engage different portions of the apertures  620  in corner fittings  612 A-C and thus use different aperture engagement portions  619  and  621 . For example, clip  616  interfaces with flat portions of apertures  610  in corner fittings  612 A and  612 B while clip  618  interfaces with curved portions of apertures  610  in corner fittings  612 B and  612 C. 
     FIGS.  6 C 1 - 6 C 4  depict four different corner fittings  620 A- 620 C, which each have a different aperture geometry. In this example, corner fitting  620 B includes an aperture  642  like that found on a top face of an ISO top corner fitting, or a bottom face of a bottom corner fitting; corner fitting  620 C includes an aperture  644  like that found on a forward or rear face of an ISO top corner fitting; and corner fitting  620 D includes an aperture  646  like that found on a side face of an ISO top or bottom corner fitting. Thus, different clips with different aperture engagement portions designed for the various aperture geometries are depicted. 
     For example, clips  622  are shown attached to corner fitting  620 A with an aperture engagement portion  623  based on aperture  640 &#39;s geometry. Because corner fitting  620 A includes an aperture  640  with circular geometry, clips  622  of the same type are able to interface with aperture  640  from multiple directions. 
     Corner fitting  620 B on the other hand, includes an aperture  642  with a different geometry, and thus clips  624  and  626  have different aperture engagement portions  625  and  627  to interface with different portions of aperture  642 . Further, the clips have different lengths based on the distance from the aperture engagement surface to the edge of the corner fitting. 
     Similarly, corner fitting  620 C includes an aperture  644  with another different geometry, and thus clips  632  and  628  have different aperture engagement portions  629  and  633  to interface with different portions of aperture  644 . And here again, the clips have different lengths based on the distance from the aperture engagement surface to the edge of the corner fitting. 
     Finally, corner fitting  620 D includes an aperture  646  with another different geometry, and thus clips  630  and  628  have different aperture engagement portions  629  and  631  to interface with different portions of aperture  644 . And here again, the clips have different lengths based on the distance from the aperture engagement surface to the edge of the corner fitting. However, note here that clips  628  works on aperture  646  as well as  644  despite the different aperture geometries. 
     In order to make the corner fitting clips more versatile in view of the many different corner fitting geometries available,  FIGS. 7A-7C  depict modular, two-part corner fitting clips, which allow for mixing and matching shapes. 
     For example,  FIG. 7A  depicts two modular corner fitting clip parts  702  and  704 , which include modular connectors  706  and  708 , respectively. Notably, modular connectors  706  and  708  use connector patterns with male-female features that have 180° rotational symmetry (e.g., with respect to a horizontal line cutting through the center of corner fitting clip parts  702  and  704 ), which allows the modular connector to easily interlock. In other words, if modular connector  706  is flipped 180 degrees, it then matches modular connector  708 . Thus, for example, two of the same pieces (e.g., two corner fitting clip parts  702 ) can be connected together to form a clip with the same geometry on each side of the clip, or clip parts with different geometries can be joined in different orientations, as depicted in  FIG. 7B . 
       FIG. 7C  depicts an example of modular corner fitting clip parts  702  and  704  connecting two corner fittings  710  and  712  having different aperture geometries. 
     Notably, while  FIGS. 7A-7C  depict an example with two specific modular corner fitting clip parts  702  and  704 , any clip design can serve as one of the modular clip parts. Further, markings may be added to the corner fittings and/or the clip parts to indicate which clip shapes will fit which corner fitting aperture geometries. 
     FIGS.  8 A 1 - 8 B 4  depict examples of clip and corner fitting features for further retaining clips. 
     For example, in FIGS.  8 A 1 - 8 A 4 , corner fittings  800 A-D include clip retainer recesses  802 A-F. The recesses may interface with one or more clip placement pins ( 804 A-F) on a clip, such as shown in FIGS.  8 B 1 - 8 B 4 . Though not depicted in FIGS.  8 A 1 - 8 A 4 , in some embodiments, the engagement recesses (e.g.,  108  in  FIG. 1 ) may be used as clip retainer recesses  802 A-F. 
     As depicted in FIGS.  8 A 1 - 8 B 4 , the position of the clip placement pins may be specific to the type of clip used (or the type of modular clip part used). Beneficially, the combination of clip retainer recesses (e.g.,  802 A-F) and clip placement pins ( 804 A-F) precludes the installation of the wrong clip geometry on a particular corner fitting. 
     Notably, while these examples shows clip placement pins being the same size and shape, in other embodiments the clip placement pins may be different sizes and shapes, which could further assist with discriminating the particular clips that work particular corner fitting designs. 
       FIGS. 9A-9E  depict an example self-locking corner fitting clip with an integral retention mechanism. 
     In particular,  FIG. 9A  depicts a split view of a clip  910  configured to interface with corner fittings  902 A and  902 B of containers  900 A and  900 B. 
     As depicted in  FIG. 9B , Clip  910  includes an integral retention mechanism comprising a hinged, extendable brace  912  and a flexible arm  916  with an engagement tab  914  at its end. 
     Corner fittings  902 A and  902 B include apertures that form internal volumes  906 A and  906 B, respectively. Within the internal volumes are shelves  904 A and  904 B, which are configured to interface with the engagement tabs  914  on clip  910 . In some embodiments, the tab is approximately 0.25 inches wide. 
     Further, corner fittings  902 A and  902 B include chamfers  909 A and  909 B to guide the flexible arms and tabs into the internal volumes  906 A and  906 B. In some embodiments, this chamfer need not be around the whole circumference of the aperture leading to the internal volume, but only where the tab is expected to interface with the corner fitting. 
       FIG. 9C  depicts clip  910  in the process of being inserted (in the direction of the arrow) into internal volumes  906 A and  906 B. While being inserted, the flexible arms  916  will elastically bend to allow the tabs to move outward from the main body of clip  910 . 
       FIG. 9D  depicts clip  910  full engaged with corner fittings  902 A and  902 B. Notably, the tabs  914  have moved into shelves  904 A and  904 B of the corner fittings, which serve to retain clip  910  in its position and prevent it from movement outward from the corner fittings. 
     Further, the braces  912  are now filly extended and locked into further shelves  908 A and  908 B within the inner volumes  906 A and  906 B of corner fittings  902 A and  902 B. To lock braces  912  into place, the center joint of the braces are pushed over-the-center so that they are bent slightly inward i.e., in the same direction of the clip insertion. In this embodiment, the joint is designed so that further rotation past this position is prevented. Thus, braces  912  are configured to function as a column that will prevent the tabs  914  from moving away from the shelf. 
     In order to disengage clip  910  from corner fittings  902 A and  902 B, the center joint of braces  912  are pulled outward as depicted in  FIG. 9E . In this position, braces  912  no longer resist tab  914  from moving away from the shelves  904 A and  904 B. Further, force is put onto the outer leg of each brace  912  to rotate it outward about the center of rotation at shelves  908 A and  908 B. This action pulls tab  914  away from the shelves. 
     With tab  914  pulled away from shelves  904 A and  904 B, clip  910  may be pulled outward away from the fittings. Once tab  914  has cleared the shelves  904 A and  904 B, it can be allowed to spring back to push against the side of the hole. 
     Notably,  FIGS. 9A-9E  depict one possible design of a self-locking corner fitting clip, but other, self-locking mechanisms are possible, such as spring-loaded self-locking clips and other biased clip designs. 
     Example Method for Connecting Containers 
       FIG. 10  depicts an example method  1000  for connecting containers. 
     Method  1000  begins at step  1002  with attaching a tool to a first corner fitting of a first container and a second corner fitting of a second container. In some embodiments, the tool comprises: a first slideable portion comprising a first plurality of pins and a rack; and a second slideable portion slideably connected to the first slideable portion and comprising a second plurality of pins and a rotatable pinion in contact with the rack, such as depicted above in FIGS.  2 B 1 ,  2 B 2 ,  2 C 1 ,  2 C 2 ,  3 A, and  3 B. In some embodiments, attaching the tool comprises: inserting the first plurality of pins on the first slidable portion into a first plurality of engagement recesses in the first corner fitting; and inserting the second plurality of pins on the second slideable portion into a second plurality of engagement recesses in the second corner fitting, such as depicted above in FIGS.  2 B 1 ,  2 B 2 ,  2 C 1 ,  2 C 2 ,  3 A, and  3 B. 
     Method  1000  then proceeds to step  1004  with applying a torque to the rotatable pinion in order to cause: the first slideable portion to apply a first force to the first corner fitting in a first direction and move the first container in the first direction; and the second slideable portion to apply a second force to the second container in a second direction, opposite the first direction, and move the second container in the second direction. In some examples, the torque may be applied via a manual tool, such as a wrench or a ratcheting wrench that provides a mechanical advantage through a lever arm. In other examples, the torque may be applied by a machine tool, such as a powered driver that provides a mechanical advantage through gearing. Notably, they are just some examples, and many other mechanisms for applying torque are possible. 
     Method  1000  then proceeds to step  1006  with removing the tool from the first corner fitting and the second corner fitting after the first corner fitting is moved into engagement with the second corner fitting. 
     Method  1000  then proceeds to step  1008  with affixing a corner fitting clip to an aperture in the first corner fitting and an aperture in the second corner fitting. 
     In some embodiments, steps  1002 - 1006  can be reversed to move the first container and second container apart. 
     In some embodiments of method  1000 , the corner fitting clip comprises a first corner fitting clip part connected to a second corner fitting clip part, such as depicted above in  FIGS. 7A-7C . 
     In some embodiments of method  1000 , the first corner fitting clip part comprises an aperture engagement portion of a first design, and the second corner fitting clip part comprises an aperture engagement portion of a second design, such as depicted above in  FIGS. 7A-7C . 
     In some embodiments of method  1000 , the first corner fitting and the second corner fitting each comprises a plurality of surface connector arrangements, each surface connector arrangement of the plurality of surface connector arrangements comprises at least two connector elements, at least one connector element of the at least two connector elements is of a first type, and at least one connector element of the at least two connector elements is of a second type, such as depicted above in  FIGS. 1A-1B, 2A - 2 D 2 , and  3 A- 3 B. 
     In some embodiments of method  1000 , applying the torque to the rotatable pinion further causes: one or more surface connectors of the first type on the first corner fitting to engage with one or more surface connectors of the second type on the second corner fitting, such as depicted above in FIGS.  2 C 1 ,  2 C 2 ,  2 D 1 , and  2 D 2 . 
     In some embodiments of method  1000 , each surface connector arrangement of the plurality of surface connector arrangements comprises an engagement recess in a center of the surface connector arrangement, such as depicted above in FIGS.  2 B 1 ,  2 B 2 ,  2 C 1 ,  2 C 2 ,  3 A, and  3 B. 
     In some embodiments of method  1000 , a center of each surface connector arrangement of the plurality of surface connector arrangements is located 1.993 inches from a center of another surface connector arrangement of the plurality of surface connector arrangements, such as depicted above in  FIGS. 1A-1B . 
     In some embodiments of method  1000 , the first corner fitting comprises a first aperture centered approximately 3.379 inches from a first edge of the first corner fitting and approximately 3.379 inches from a second edge of the first corner fitting, and the second corner fitting comprises a second aperture centered approximately 3.379 inches from a first edge of the second corner fitting and approximately 3.379 inches from a second edge of the second corner fitting, such as depicted above in  FIGS. 1A-1B . 
     In some embodiments of method  1000 , the first corner fitting comprises a first exterior dimension of 5.983 inches and a second exterior dimension of 5.983 inches, and the second corner fitting comprises a first exterior dimension of 5.983 inches and a second exterior dimension of 5.983 inches, such as depicted above in  FIGS. 1A-1B . 
       FIG. 11  depicts an example method  1100  of securing containers. 
     Method  1100  begins at step  1102  with determining a first aperture geometry of an aperture of a first corner fitting. For example, different aperture geometries are depicted and described above with respect to  FIGS. 6A - 6 C 4 . 
     Method  1100  then proceeds to step  1104  with determining a second aperture geometry of an aperture of a second corner fitting. 
     Method  1100  then proceeds to step  1106  with selecting a corner fitting clip based on the first aperture geometry and the second aperture geometry. 
     In some embodiments of method  1100 , selecting a corner fitting clip based on the first aperture geometry and the second aperture geometry comprises: selecting a first corner fitting clip part based on the first aperture geometry; and selecting a second corner fitting clip part based on the second aperture geometry. 
     In some embodiments of method  1100 , the first corner fitting clip part comprises a first modular connector and the second corner fitting clip part comprises a second modular connector, such as depicted in  FIGS. 7A-7C . Further, in some embodiments the first modular connector is 180 degree symmetric with the second modular connector, such as depicted in  FIGS. 7A-7C . 
     In some embodiments of method  100 , the first corner fitting clip part comprises a first aperture engagement portion, and the second corner fitting clip part comprises a second aperture engagement portion. In some embodiments, the first aperture engagement portion is different from the second aperture engagement portion. 
     In some embodiments, method  1100  further comprises attaching the first corner fitting clip part to the second corner fitting clip part to form the corner fitting clip. 
     Method  1100  then proceeds to step  1108  with affixing the corner fitting clip to the aperture of the first corner fitting and the aperture of the second corner fitting. 
     The preceding description is provided to enable any person skilled in the art to practice the various embodiments described herein. The examples discussed herein are not limiting of the scope, applicability, or embodiments set forth in the claims. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. For example, changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. 
     As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. 
     As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c). 
     As used herein, “approximately” with respect to a dimension means plus or minus standard manufacturing tolerances. 
     The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. Further, the various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions.