Patent Publication Number: US-10781037-B2

Title: Roof for a modular shipping container

Description:
RELATED APPLICATIONS 
     Not Applicable. 
     BACKGROUND 
     Shipping containers used to move cargo are generally large box-like structures. Providing these shipping containers to users in the field is difficult due to their weight and size. As such, a limited number of containers can be moved at one time in a fully assembled form. To overcome this logistical hurdle, some shipping containers are designed to be modular. That is, modular shipping containers are designed to be shipped in a disassembled state and then reassembled on-site. 
     An inherent property of modular shipping containers is that they include various disconnected parts, which must be assembled by an end user to ensure the parts are properly connected and aligned to form the container. An end user of modular shipping containers may experience significant costs associated with the time required to assemble a container, and the shipping space occupied by the container in a disassembled state (i.e., a shipping space may define how many containers are shipped to an end user). Additionally, improper assembly may lead to potential leak paths forming within the container. 
     SUMMARY 
     The present invention provides systems and method for a modular shipping container. In one aspect, the present invention provides a base for a modular shipping container. The base includes a base frame having a first end rail, a second end rail, a first side rail, and a second side rail. The first end rail is attached to first ends of the first side rail and the second side rail, and the second end rail is attached to second ends of the first side rail and the second side rail to form a periphery of the base. The base further includes a pair of fork tunnel assemblies removably coupled to the first side rail and the second side rail and extending therebetween. The pair of fork tunnel assemblies are spaced along the base frame to define a fork pocket distance therebetween. The fork pocket distance defined between the pair of fork tunnel assemblies is configurable between a first fork pocket distance and a second fork pocket distance. 
     In another aspect, the present invention provides a modular shipping container including a base. The base includes a base frame having a first end rail, a second end rail, a first side rail, and a second side rail. The first end rail is attached to first ends of the first side rail and the second side rail, and the second end rail is attached to second ends of the first side rail and the second side rail to form a periphery of the base. The modular shipping container further includes a pair of fork tunnel assemblies removably coupled to the first side rail and the second side rail and extending therebetween. The pair of fork tunnel assemblies are spaced along the base frame to define a fork pocket distance therebetween. The modular shipping container further includes a first end wall, a second end wall, a first side wall, a second side wall, and a roof configured to be coupled to the first end wall, the second end wall, the first side wall, and the second end wall opposite the base. The fork pocket distance defined between the pair of fork tunnel assemblies is configurable between a first fork pocket distance and a second fork pocket distance. The first fork pocket distance being greater than the second fork pocket distance. 
     In one aspect, the present invention provides a fork tunnel assembly for a modular shipping container. The modular shipping container defines a central axis and includes a base frame having a first end rail, a second end rail, a first side rail, and a second side rail, and a floor supported by the base frame. The fork tunnel assembly includes a fork tunnel and a pair of attachment plates attached to opposing ends of the fork tunnel. Each attachment plate is configured to be removably coupled to one of the first side rail and the second side rail. A fork pocket distance defined between the central axis and the fork tunnel is configurable between a first fork pocket distance and a second fork pocket distance. The first fork pocket distance being greater than the second fork pocket distance. 
     In another aspect, the present invention provides a roof for a modular shipping container. The modular shipping container includes a first end wall, a second end wall, a first side wall, and a second side wall. The roof includes a roof sheet having a top surface and defining a first end, a second end, a first side, and a second side. The roof further includes a pair of skid plate assembles. One of the pair of skid plate assembles is arranged along the first side of the roof sheet, and the other of the pair of skid plate assemblies is arranged along the second side of the roof sheet. The pair of skid plate assemblies partially extend over the top surface of the roof sheet. The roof sheet is formed of a unitary piece of material. 
     In one aspect, the present invention provides a modular shipping container including a base, a first end wall, a second end wall, a first side wall, a second side wall, and a roof removably coupled to each of the first end wall, the second end wall, the first side wall, and the second side wall. The roof includes a roof sheet having a top surface and defining a first end, a second end, a first side, and a second side. The roof further includes a pair of skid plate assembles. One of the pair of skid plate assembles is arranged along the first side of the roof sheet, and the other of the pair of skid plate assemblies is arranged along the second side of the roof sheet. The pair of skid plate assemblies partially extend over the top surface of the roof sheet. The roof sheet is formed of a unitary piece of material. 
     In another aspect, the present invention provides a side wall assembly for a modular shipping container. The modular shipping container includes a base and a side wall. The side wall assembly includes a tube hinge and a first hinge pin assembly having a first hinge pin extending therefrom. The first hinge pin is configured to be received within a first end of the tube hinge. The side wall assembly further includes a second hinge pin assembly having a second hinge pin extending therefrom. The second hinge pin is configured to be received within a second end of the tube hinge opposite the first end. The tube hinge, the first hinge pin assembly, and the second hinge pin assembly are configured to enable the side wall to pivotally rotate with respect to the base. 
     In one aspect, the present invention provides a modular shipping container including a base, a first end wall, a second end wall, a first side wall having a first side tube hinge coupled to a bottom end thereof, and a second side wall having a second side tube hinge coupled to a bottom end thereof. The modular shipping container further includes a first pair of hinge pin assemblies each configured to engage the first side tube hinge to pivotally couple the first side wall to the base. The modular shipping container further includes a second pair of hinge pin assemblies each configured to engage the second side tube hinge to pivotally couple the second side wall to the base. 
     In another aspect, the present invention provides a stacking bracket assembly for securing a plurality of modular shipping containers in a stacked arrangement. The stacking bracket assembly includes a plurality of stacking brackets each having a vertical stacking tube and a horizontal stacking tube. Each horizontal stacking tube is dimensioned to be received within one of a plurality of stacking tubes extending from one of the plurality of modular shipping containers. Each vertical stacking tube is dimensioned to receive a stacking adapter to couple an end of one of the plurality of stacking brackets to an opposing end of an adjacent one of the plurality of stacking brackets. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially exploded top, front, left isometric view of a modular shipping container in a disassembled state according to one aspect of the present disclosure. 
         FIG. 2  is a partially exploded top, front, left, isometric view of the modular shipping container of  FIG. 1  in a partially assembled state with a pair of end walls partially erected. 
         FIG. 3  is a partially exploded top, front, left isometric view of the modular shipping container of  FIG. 1  in a partially assembled state with a pair of end walls and a side wall erected, and another side wall pivoted. 
         FIG. 4  is a top, front, left isometric view of the modular shipping container of  FIG. 1  in an assembled state. 
         FIG. 5  is a top, front, left isometric view of the modular shipping container of  FIG. 4  with a roof, a side wall, and an end wall removed. 
         FIG. 6  is a magnified view of a sliding hinge of the modular shipping container of  FIG. 5 . 
         FIG. 7  is a cross-sectional view of the sliding hinge of  FIG. 6  taken generally along the line  7 - 7  of  FIG. 6 . 
         FIG. 8  is a cross-sectional view of the sliding hinge of  FIG. 6  taken generally along the line  8 - 8  of  FIG. 6 . 
         FIG. 9  is a schematic illustration of the sliding hinge of  FIG. 7  in a disassembled state. 
         FIG. 10  is a schematic illustration of the sliding hinge of  FIG. 7  in a partially assembled state with a side wall pivoting about the sliding hinge. 
         FIG. 11  is a schematic illustration of the sliding hinge of  FIG. 7  in a partially assembled state with a side wall erected and unfastened. 
         FIG. 12  is a schematic illustration of the sliding hinge of  FIG. 7  in an assembled state with a side wall erected and fastened. 
         FIG. 13  is an magnified view of a portion of the modular shipping container of  FIG. 5 . 
         FIG. 14  is a magnified view of a retainer flange coupled to an end wall of the modular shipping container of  FIG. 13 . 
         FIG. 15  is a partial top, rear, left isometric view of the modular shipping container of  FIG. 5 . 
         FIG. 16  is a magnified view of a retainer flange coupled to an end wall of the modular shipping container of  FIG. 15 . 
         FIG. 17  is cross-sectional bottom, front, left isometric view of the modular shipping container of  FIG. 4  taken generally along the line  17 - 17  of  FIG. 4 . 
         FIG. 18  is a magnified view of a clamp of the modular shipping container of  FIG. 17 . 
         FIG. 19  is a cross-sectional view of the clamp of the modular shipping container of  FIG. 18  taken generally along the line  19 - 19  of  FIG. 18 . 
         FIG. 20  is a top, front, left isometric view of a modular shipping container according to another aspect of the present disclosure. 
         FIG. 21  is a top, front, left isometric view of a base of the modular shipping container of  FIG. 20 . 
         FIG. 22A  is a top, front, left isometric view of a base of the modular shipping container of  FIG. 20  with a floor removed from the base. 
         FIG. 22B  is a magnified view of a portion of  FIG. 22A . 
         FIG. 22C  is a magnified view of another portion of  FIG. 22A . 
         FIG. 23  is a top, front, left isometric view of a fork tunnel assembly of the modular shipping container of  FIG. 20 . 
         FIG. 24  is a left side view of the fork tunnel assembly of  FIG. 23 . 
         FIG. 25  is a cross-sectional view of the fork tunnel assembly of  FIG. 24  taken generally along the line  25 - 25  of  FIG. 24 . 
         FIG. 26A  is a bottom, front, left isometric view of the base of  FIG. 22A  with a pair of fork tunnel assemblies in a first configuration. 
         FIG. 26B  is a bottom, front, left isometric view of the base of  FIG. 22A  with a pair of fork tunnel assemblies in a second configuration. 
         FIG. 27A  is a front view of the base of  FIG. 22A  with a pair of fork tunnel assemblies in a first configuration. 
         FIG. 27B  is a front view of the base of  FIG. 22A  with a pair of fork tunnel assemblies in a second configuration. 
         FIG. 28  is a schematic illustration of the pair of fork tunnel assemblies arranged in the base  FIG. 22  switching between the first configuration and the second configuration of  FIGS. 26A-27B . 
         FIG. 29  is a top, front, left isometric view of a roof of the modular shipping container of  FIG. 20 . 
         FIG. 30  is a bottom, front, left isometric view of the roof of the modular shipping container of  FIG. 20 . 
         FIG. 31  is magnified view of a portion of the roof of  FIG. 29 . 
         FIG. 32  is an exploded top, front, left isometric view of the roof of the modular shipping container of  FIG. 20 . 
         FIG. 33  is a cross-sectional view of the modular shipping container of  FIG. 20  taken generally along the line  33 - 33  of  FIG. 20 . 
         FIG. 34  is a magnified view of a portion of the modular shipping container of  FIG. 33 . 
         FIG. 35  is a bottom, back, left isometric view of a portion of the modular shipping container of  FIG. 33 . 
         FIG. 36  is a cross-sectional view of the modular shipping container of  FIG. 20  taken generally along the line  36 - 36  of  FIG. 20 . 
         FIG. 37  is a magnified view of a portion of the modular shipping container of  FIG. 36 . 
         FIG. 38  is a bottom, front, right isometric view of a portion of the modular shipping container of  FIG. 36 . 
         FIG. 39  is a left side view of the modular shipping container of  FIG. 20  with a first end wall removed. 
         FIG. 40  is a magnified top, front, left isometric view of a portion of the modular shipping container of  FIG. 39 . 
         FIG. 41A  is a magnified top, back, left isometric view of a portion of the modular shipping container of  FIG. 39 . 
         FIG. 41B  is a magnified top, front, left isometric view of a portion of the modular shipping container of  FIG. 39 . 
         FIG. 42  is a top, front, right isometric view of a first stationary hinge pin assembly of the modular shipping container of  FIG. 20 . 
         FIG. 43  is a top, front, right isometric view of a first removable hinge pin assembly of the modular shipping container of  FIG. 20 . 
         FIG. 44  is a top, back, left isometric view of a second stationary hinge pin assembly of the modular shipping container of  FIG. 20 . 
         FIG. 45  is a top, back, left isometric view of a second removable hinge pin assembly of the modular shipping container of  FIG. 20 . 
         FIG. 46A  is a schematic illustration of a side wall of the modular shipping container of  FIG. 20  in an erected, or final, position. 
         FIG. 46B  is a schematic illustration of a side wall of the modular shipping container of  FIG. 20  pivotally rotating. 
         FIG. 46C  is a schematic illustration of a side wall of the modular shipping container of  FIG. 20  in a disassembled, or collapsed, state. 
         FIG. 47A  is a partially exploded top, back, right isometric view of the modular shipping container of  FIG. 20  in a disassembled state, or kit form. 
         FIG. 47B  is a partially exploded top, back, right isometric view of the modular shipping container of  FIG. 20  in a partially assembled state with a pair of end walls partially erected. 
         FIG. 47C  is a partially exploded top, back, right isometric view of the modular shipping container of  FIG. 1  in a partially assembled state with a pair of end walls and a side wall erected, and another side wall pivoted. 
         FIG. 47D  is a top, back, right isometric view of the modular shipping container of  FIG. 20  in an assembled state. 
         FIG. 48  is a top, front, left, isometric view of a plurality of the modular shipping containers of  FIG. 20  in a disassembled state stacked on top of one another. 
         FIG. 49  is a magnified view of a portion of the stacked modular shipping containers of  FIG. 48 . 
         FIG. 50  is a top, front, right, isometric view of a stacking bracket used to stack the modular shipping containers of  FIG. 48 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention. 
       FIG. 1  illustrates a modular shipping container  10  according to one aspect of the present disclosure. The modular shipping container  10  includes a roof  12  and body  14 . The roof  12  is positioned on body  14  for transportation of the modular shipping container  10  to a user. A profile of the modular shipping container  10  is smaller in a disassembled state ( FIG. 1 ) when compared to a profile of the modular shipping container  10  in an assembled state ( FIG. 4 ). As such, multiple modular shipping containers  10  may be stacked onto one another and transported to a user for final assembly. 
     The body  14  includes a floor  16 , a front wall  11  coupled to floor  16 , and a rear wall  13  coupled to floor  16 , as illustrated in  FIG. 1 . The front and rear walls  11 ,  13  are shown in a flattened transport position. To assemble the modular shipping container  10 , a user removes roof  12  from body  14 , as illustrated in  FIG. 1 . The user then pivots front wall  11  and rear wall  13  relative to floor  16  from the flattened transport position to an erected support position, as illustrated in  FIG. 2 . 
     The body  14  also includes a left side wall  15  and a right side wall  17  coupled to floor  16 , as illustrated in  FIG. 3 . The user pivots left side wall  15  from a flattened transport position, illustrated in  FIG. 2 , to an erected support position, illustrated in  FIG. 3 . The user also pivots the right side wall  17  to an erected support position as illustrated in  FIG. 3 . In the illustrative embodiment, the left and the right side walls  15 ,  17  are stored beneath the front and the rear walls  11 ,  13  in the flattened transport position. The roof  12  is coupled to body  14  at upper edges of the walls  11 ,  13 ,  15 ,  17  to form the assembled modular shipping container, as illustrated in  FIG. 4 . 
     In the illustrative embodiment, the front wall  11  and the rear wall  13  are substantially similar except that that front wall  11  includes doors for accessing an interior space within the assembled modular shipping container, as illustrated in  FIG. 1 . In the illustrative embodiment, the left wall  15  and the right wall  17  are also substantially similar in construction. As such, the discussion below of the rear wall  13  also applied to the front wall  11 , and the discussion below of the left side wall  15  also applies to the right side wall  17 . However, it should be noted that, in some embodiments, the walls  11 ,  13 ,  15 ,  17  may have varying constructions and configurations relative to one another, as desired. 
     As shown in  FIG. 5 , the floor  16  includes a deck  160  and a pair of side rails  19  that extend upward from the deck  160  and alongside a periphery thereof. A sliding hinge  18  in accordance with the present disclosure secures left side wall  15  with floor  16 , as shown in  FIGS. 5 and 6 . The sliding hinge  18  is coupled to left side wall  15  and side rail  19  to secure the left side wall  15  to the floor  16 . In the illustrative embodiment, multiple sliding hinges  18  are used to secure the left side wall  15  to the floor  16 . 
     The sliding hinge  18  includes a bracket  22  coupled to the left side wall  15 , a sleeve  24  positioned within the bracket  22  and coupled to the side rail  19  of the floor  16 , and a fastener  26  extending through the bracket  22  and the sleeve  24 , as illustrated in  FIG. 6 . The bracket  22  is formed to include a slot  29  which receives the fastener  26 , as illustrated in  FIGS. 7 and 8 . In the illustrative embodiment, the fastener  26  is in the form of a bolt. In some embodiments, other fasteners may be used, for example, pins. An upper portion of the bracket  22  is secured to the left side wall  15  and a lower portion of the bracket  22  is spaced apart from the left side wall  15  to define a gap  28  therebetween. The gap  28  is configured to receive a portion of the side rail  19  to align the left side wall  15  with the floor  16  in the erected support position. The sleeve  24  is secured to the side rail  19 , as illustrated in  FIG. 8 . In some embodiments, the sleeve  24  is welded to the side rail  19 . 
     As illustrated in  FIG. 9 , the fastener  26  contacts an end of the slot  29  to allow the left side wall  15  to pivot relative to the floor  16 . As the left side wall  15  pivots, a lower portion of the left side wall  15  passes over the side rail  19 , as illustrated in  FIG. 10 . The left side wall  15  is pivoted until the side rail  19  is substantially aligned with the gap  28 , as illustrated in  FIG. 11 . The left side wall  15  is lowered until the fastener  26  engages the other end of the slot  29  and the side rail  19  is received in the gap  28 , as illustrated in  FIG. 12 . The left side wall  15  overlaps with the side rail  19  by a distance D to resist the entry of water, such as from rain, or other liquids into the assembled modular shipping container  10 . 
     Skilled workers may not be required to be on-site to assemble the modular shipping container  10  due to the secure connections between the walls  11 ,  13 ,  15 ,  17  and the floor  16 . For example, the sliding hinge  18  can be installed at a manufacturing facility of the modular shipping container  10  such that the left and the right side walls  15 ,  17  are properly aligned with floor  16  when in the erected support position. Similarly, the front and the rear walls  11 ,  13  may be attached and properly aligned with the floor  16  at the manufacturing facility. No subsequent alignment of the walls  11 ,  13 ,  15 ,  17  may be required. As such, a user simply has to pivot the walls  11 ,  13 ,  15 ,  17  into the erected support position and attach the roof  12  to the body  14  to assemble the modular shipping container  10 . In some embodiments, the modular shipping container  10  is delivered to a user with the fasteners  26  removed from sliding hinges  18 . In such an embodiment, the user aligns the brackets  22  with the sleeves  24  to insert the fasteners  26 . No additional alignment may be necessary because the sliding hinges  18  may be aligned prior to delivery of the modular shipping container  10  to the user. 
     The rear wall  13  includes a pair of retainer flanges  32 , as illustrated in  FIG. 13 . The retainer flanges  32  are coupled to the side rails  19  to allow the rear wall  13  to pivot about a pivot axis P 1  relative to the floor  16 , as illustrated in  FIGS. 13 and 14 . The sliding hinge  18  is configured to allow the left side wall  15  to pivot about a pivot axis P 2  relative to the floor  16 , as illustrated in  FIG. 14 . The pivot axis P 1  is generally perpendicular to pivot axis P 2 . In the illustrative embodiment, a lock plate  34  is coupled between the retainer flange  32  and the left side wall  15  to maintain the left side wall  15  and the rear wall  13  in the erected support position. 
     The retainer flange  32  is positioned to engage with the left side wall  15  when the left side wall  15  is moved to the erected support position, as illustrated in  FIGS. 15 and 16 . The retainer flange  32  overlaps the left side wall  15  to resist the entry of water, such as from rain, or other liquids into the modular shipping container  10 , when assembled. The left side wall  15  engages with the retainer flange  32  to form a continuous side of the modular shipping container  10 . 
     In some embodiments, the front and the rear walls  11 ,  13  are removed from the floor  16  prior to delivery of the modular shipping container  10  to a user. In such an embodiment, the user aligns the front and the rear walls  11 ,  13  with the floor  16  and inserts fasteners through the retainer flanges  32  and the side rails  19  to secure the front and the rear walls  11 ,  13  to the floor  16 . Holes for receiving the fasteners are formed in the side rails  19  and the retainer flanges  32  prior to delivery to the user. As such, no skilled workers may be necessary to align the front and the rear walls  11 ,  13  with the floor  16 . In some embodiments, the front and the rear walls  11 ,  13  are secured to the floor  16  by sliding hinges. 
     The roof  12  includes a panel  42 , a perimeter frame  44 , and a plurality of support ribs  46  coupled to the perimeter frame  44  to support the panel  42 , as illustrated in  FIG. 17 . One or more clamps  48  secure the roof  12  to the body  14 . Each clamp  48  includes a J-shaped channel  41 , engaged with the support rib  46  and an upper edge of the walls  11 ,  13 ,  15 ,  17 , and a fastener  43  (e.g., a bolt), extending through the support rib  46  and the J-shaped channel  41 , as illustrated in  FIGS. 18 and 19 . 
     In illustrative embodiments, a sliding hinge mounts to the bottom of a container side wall allowing for easy field assembly of a shipping container. The sliding hinge allows the side walls to be shipped in a folded position to increase the number of units that can be transported at a time. On site, the sliding hinge allows for the easy erection of the walls and aligns the walls in their final position. The sliding of the hinge allows the folded walls to sit inside the base (floor) frame and folded end walls. The sliding hinge also allows overlap of the side walls over the base frame in the assembled position to assist in water shedding. 
     In illustrative embodiments, the sliding hinge reduces the total shipping height of a modular shipping container in a disassembled, or shipping ready, state. The sliding hinge decreases the potential for water penetration into the container by increasing the water shedding abilities of the side walls. The sliding hinge increases the assembly ease of the final shipping container by aligning the side walls in their final position. 
       FIG. 20  illustrates a modular shipping container  200  according to another aspect of the present disclosure. The modular shipping container  200  includes a base  202 , a first end wall  204 , a second end wall  206 , a first side wall  208 , a second side wall  210 , and a roof  212 . As will be described, each of the first side wall  208  and the second side wall  210  are pivotally coupled to the base  202  to enable the modular shipping container  200  to be easily assembled and disassembled. In the illustrated embodiment of  FIG. 20 , the first end wall  204  and the second end wall  206  define a generally shorter length than the first side wall  208  and the second side wall  210 . As such, the illustrated modular shipping container  200  defines a generally rectangular prism shape. In other embodiments, for example, the size of the first and second end walls  204  and  206  relative to the first and second side walls  208  and  210  may vary to define alternative shapes of the modular shipping container  200 . 
       FIGS. 21 and 22A -C illustrate the base  202  of the modular shipping container  200 . The base  202  includes a base frame  213 , a floor  214 , a plurality of support beams  216 , and a pair of fork tunnel assemblies  218 . The base frame  213  includes a first end rail  220 , a second end rail  222 , a first side rail  224 , and a second side rail  226 . The illustrated base  202  can define a generally rectangular shape. That is, the first and second end rails  220  and  222  define a shorter length than the first and second side rails  224  and  226 . The first side rail  224  includes a first inner rail  228  and a first outer rail  230  coupled to the first inner rail  228 . Similarly, the second side rail  226  includes a second inner rail  232  and a second outer rail  234  coupled to the second inner rail  232 . 
     The first side rail  224  is attached to the first end rail  220  adjacent to a distal end  236  thereof and is coupled to the second end rail  222  adjacent to a distal end  238  thereof. The second side rail  226  is coupled to the first end rail  220  adjacent to an opposing distal end  240  thereof, and is coupled to the second end rail  222  at opposing distal end  242  thereof. The base frame  213  forms a periphery of the generally rectangular shape defined by the base  202 . 
     The first end rail  220  includes a first stationary hinge pin assembly  244  coupled to the distal end  236  and a second stationary hinge pin assembly  246  coupled to the opposing distal end  240 . The first and second stationary hinge pin assemblies  244  and  246  may be welded to the first end rail  220 . In other embodiments, the first and second stationary hinge pin assemblies  244  and  246  may be coupled to the first end rail  220  via another attachment mechanism (e.g., an adhesive, one or more fasteners, etc.). The second end rail  222  includes a plurality of first hinge apertures  248  formed within the distal end  238  and a plurality of second hinge apertures  250  formed within the distal end  242 . 
     In some embodiments, the distal ends  236 ,  238 ,  240 , and  242  may define the corners of the periphery formed by the base frame  213 . Thus, the base frame  213  includes the first and second stationary hinge pin assemblies  244  and  246  coupled to adjacent corners thereof, and includes the plurality of first and second hinge apertures  248  and  250  arranged on longitudinally opposing adjacent corners thereof. 
     Still referring to  FIGS. 21 and 22A-22C , the floor  214  is supported by the base frame  213  and coupled thereto. The illustrated floor  214  is formed by a plurality of panels  252  each fastened to the base frame  213 , one or more of the plurality of support beams  216 , and/or one of the pair of fork tunnel assemblies  218 . In other embodiments, for example, the floor  214  may be formed as a unitary component. The floor  214  provides a surface on which items may be stored within the modular shipping container  200 , when assembled. 
     Each of the plurality of support beams  216  is coupled to the first inner rail  228  and to the second inner rail  232 , and extend therebetween. Each of the illustrated plurality of support beams  216  defines a generally I-beam shape in cross-section. In other embodiments, for example, the plurality of support beams  216  may define an alternative shape, as desired. The illustrated base  202  includes five support beams  216 , with two arranged on each opposing side of the pair of fork tunnel assemblies  218  and one arranged between the pair of fork tunnel assemblies  218 . In other embodiments, for example, the base  202  may include more or less than five support beams  216  in any arrangement along the base  202 . 
     Each of the pair of fork tunnel assemblies  218  is in engagement with the first inner rail  228  and the second inner rail  232 , and extend therebetween. The fork tunnel assemblies  218  are arranged symmetrically about a central axis C defined by the base  202  such that a predefined distance exists therebetween. As will be described below, the fork tunnel assemblies  218  are removably coupled to the base frame  213  to enable the predefined distance defined between the pair of fork tunnel assemblies  218  to be configurable. 
     The fork tunnel assemblies  218  are symmetric about a center axis C, therefore, the following description of one of the pair of the fork tunnel assemblies  218  applies symmetrically to the other of the pair of fork tunnel assemblies  218 . Similar features between the pair of fork tunnel assemblies  218  are identified using like reference numerals.  FIGS. 23-25  illustrate one of the pair of fork tunnel assemblies  218 . The illustrated fork tunnel assembly  218  includes a fork tunnel  254 , a support flange  256 , and a pair of attachment plates  258 . The fork tunnel  254  defines a generally rectangular tunnel, or slot, which extends longitudinally along the fork tunnel assembly  218 . The fork tunnel  254  is dimensioned to receive a fork of a material handling vehicle to facilitate transportation of the modular shipping container  200 . 
     The support flange  256  is attached to an outer surface  260  of the fork tunnel  254 . The outer surface  260  is arranged adjacent to the central axis C, when the base  202  is assembled. The support flange  256  defines a generally L-shaped profile and includes a support surface  262 . The support surface  262  is arranged substantially perpendicularly to the outer surface  260 . The support flange  256  extends from the outer surface  260  such that the support surface  262  is disposed generally above the fork tunnel  254 . That is, the support flange  256  extends above the outer surface  260  such that the support surface  262  engages a bottom surface of the floor  214 , when the base  202  is assembled. In this manner, the floor  214  is partially supported by the support surface  262  and coupled thereto. 
     Each of the pair of attachment plates  258  is arranged on the respective opposing ends of the fork tunnel assembly  218  such that a portion of the fork tunnel  254  extends therethrough and protrudes therefrom. Each of the pair of attachment plates  258  includes a mounting surface  264  and an attachment plate flange  266  extending substantially perpendicularly from a bottom end of the mounting surface  264 . Each of the mounting surfaces  264  includes a plurality of tunnel mounting apertures  268  arranged around a periphery thereof for coupling the mounting surfaces  264  to the base frame  213 , as will be discussed immediately below. 
     Turning to  FIGS. 26A-27B , the first side rail  224  includes a pair of first fork tunnel cutouts  270 . Similarly, the second side rail  226  includes a pair of second fork tunnel cutouts  272 . Each of the pair of first fork tunnel cutouts  270  and the pair of second fork tunnel cutouts  272  includes a plurality of cutout mounting apertures  274  arranged around a periphery thereof. Each of the plurality of cutout mounting apertures  274  is arranged such that they align with the plurality of tunnel mounting apertures  268  on a corresponding one of the mounting surfaces  264 . A fastening element  276  is configured to be received within each of the plurality of cutout mounting apertures  274  and the corresponding one of the plurality of tunnel mounting apertures  268  aligned therewith. The fastening elements  276  removably couple each of the fork tunnel assemblies  218  to the base frame  213 . In the illustrated embodiment, the fastening elements  276  removably couple each of the mounting surfaces  264  to a corresponding one of the first side rail  224  or the second side rail  226 . The illustrated fastening elements  276  are each in the form of a bolt and a nut. In other embodiments, the fastening elements  276  may be in the form of another removable fastening mechanism (e.g., a pin, a clamp, a screw, etc.). 
     Each of the mounting surfaces  264  is dimensioned to cover a corresponding one of the first fork tunnel cutouts  270  or the second fork tunnel cutouts  272 . As described above, the fork tunnels  254  protrude from the attachment plates  258 , thus, when assembled, the mounting surfaces  264  cover the respective one of the first fork tunnel cutouts  270  or the second fork tunnel cutouts  272  except for the fork tunnels  254 , which protrude therefrom. In this manner, when the fork tunnel assemblies  218  are installed on the base frame  213 , the fork tunnels  254  define a predefined distance therebetween. Each of the fork tunnels  254  is configured to receive a fork of a material handling vehicle to enable transportation of the modular shipping container  200 . The predefined distance defined between the fork tunnels  254  generally corresponds with a distance between the forks on a material handling vehicle (i.e., a fork pocket distance). Since a distance between the forks on a material handling vehicle may be different depending on the type of material handling vehicle utilized by a given end user, it would be desirable to have a modular shipping container with a configurable fork pocket distance. As will be described, the design and arrangement of the fork tunnel assemblies  218  enables the base  202  of the modular shipping container  200  to provide a configurable fork pocket distance. This ability to configure the fork pocket distance allows an end user to choose a fork pocket spacing to correspond with whichever fork pocket spacing is necessary for the specific material handling vehicle they utilize. 
     As shown in  FIGS. 26A and 27A , the fork tunnel assemblies  218  are installed in a first configuration where a first fork pocket distance D 1  is defined between centerpoints of the fork tunnels  254 . In another interpretation, the first fork pocket distance D 1  may be defined as the sum of a distance between the centerpoint of each respective fork tunnel  254  and the central axis C. If desired, an end user may alter the fork pocket distance from the first fork pocket distance D 1  to a second fork pocket distance D 2  by moving the pair of fork tunnel assemblies  218  to a second configuration, as shown in  FIGS. 26B and 27B . The first fork pocket distance D 1  is larger than the second fork pocket distance D 2 . In order to switch between the first configuration and the second configuration, the fork tunnel assemblies  218  are detached from the base frame  213 , rotated 180 degrees, and re-coupled to the base frame  213 .  FIG. 28  illustrates the 180 degree rotation utilized to switch the pair of fork tunnel assemblies  218  between the first configuration and the second configuration. Due to the design of the pair of fork tunnel assemblies  218 , a 180 degree rotation of the pair of fork tunnel assemblies  218  enables the fork pocket distance defined between the fork tunnels  254  to be configurable between the first fork pocket distance D 1  and the second fork pocket distance D 2 . With the pair of fork tunnel assemblies  218  being removably coupled to the base frame  213 , an end user can configure the fork pocket distance in the field, if necessary. In addition, the symmetry defined by the pair of fork tunnel assembles  218  reduces the number of components in the base  202 , while providing an end user with added functionality due to the configurable nature of the pair of fork tunnel assemblies  218 . 
       FIGS. 29-32  illustrate the roof  212  of the modular shipping container  200 . The roof  212  includes a roof sheet  280  and a pair of skid plate assemblies  282 . The roof  212  defines a generally rectangular shape with a first end  284  and a second end  286  defining a generally shorter length than a first side  288  and a second side  290 . The roof sheet  280  is a unitary piece of material that is skinned over an entirety of the roof  212 . In this manner, the roof sheet  280  may reduce or eliminate seams formed thereon and thereby may reduce the chance of a leak in the roof  212 . Current roof designs on shipping containers typically include multiple pieces of material bonded together, which forms multiple seams in the roof that may provide a leak path. Fabricating the roof sheet  280  from a unitary piece of material, which is skinned over the entirety of the roof  212 , overcomes this deficiency in current shipping container designs. The roof sheet  280  is fabricated from a thin sheet of metal material (e.g., aluminum). 
     The pair of skid plate assemblies  282  are attached to a periphery of the roof sheet  280  with one of the pair of skid plate assemblies  282  arranged along the first side  288  and the other of the pair of skid plate assemblies  282  arranged along the second side  290 . Each of the pair of skid plate assemblies  282  includes a first skid end cap  292 , a second skid end cap  294 , and a skid plate  298 . Each of the first skid end caps  292  engages and partially covers the first end  284  of the roof  212 , and each of the second skid end caps  294  engages and partially covers the second end  286  of the roof  212 . Each of the skid plates  298  engages and covers the respective one of the first side  288  and the second side  290  along which the skid plate assembly  282  is arranged. Each of the skid plates  298  extends over their respective side  288  and  290  and along a top surface  300  of the roof sheet  280 . Each of the skid plates  298  extends partially over the top surface  300  of the roof sheet  280 . That is, each of the skid plates  298  extends over the top surface  300  of the roof sheet  280  an extension distance E. The extension distance E also defines how far each of the first skid end caps  292  and the second skid end caps  294  extend along the first end  284  and the second end  286 , respectively. 
     The extension distance E is defined to ensure that the skid plates  298  are attached to the roof sheet  280  outside of an envelope defined by the modular shipping container  200 . With the skid plates  298  arranged outside of the envelope of the modular shipping container  200 , there may be no direct leak paths that form outside to inside the modular shipping container  200 . The skid plate assemblies  282  are manufactured from a metal material with a higher hardness (e.g., stainless steel, steel, aluminum, composite materials, sandwiched composite materials, glass fiber reinforced polymers, carbon fiber reinforced polymers, carbon fiber, or steel strength plastics), when compared to the roof sheet  280 . The skid plate assemblies  282  structurally reinforce the roof  212  and the skid plates  298  provide locations for other containers to be stacked on top of the roof  212 . Additionally, the skid plate assemblies  282  may aid in preventing the roof sheet  280  from being punctured by other containers stacked upon or next to the roof  212 . 
     Referring to  FIGS. 30-32 , the roof  212  includes a plurality of roof bows  302  that extend between the first side  288  and the second side  290  and are spaced longitudinally under the roof sheet  280 . The plurality of roof bows  302  are secured under the roof sheet  280  at least partially between an outer angle assembly  304  and an inner angle assembly  306 . The plurality of roof bows  302  may be attached to a bottom surface  308  of the roof sheet  280  via an adhesive tape attached to one or more bow flanges  310  arranged on each of the plurality of roof bows  302 . 
     The illustrated outer angle assembly  304  extends around an inner periphery of the roof sheet  280  and is formed by a plurality of segmented outer angle supports. That is, a pair of outer end angle supports  312  are dimensioned to be arranged under the roof sheet  280  along each of the first end  284  and the second end  286 , and a pair of outer side angle supports  313  are dimensioned to be arranged under the roof sheet  280  along each of the first side  288  and the second side  290 . Similarly, the illustrated inner angle assembly  306  extends around an inner periphery of the roof sheet  280 , within the outer angle assembly  304 , and is formed by a plurality of segmented inner angle supports. That is, a pair of inner end angle supports  314  are dimensioned to be arranged under the roof sheet  280  along each of the first end  284  and the second end  286 , and a pair of inner side angle supports  315  are dimensioned to be arranged under the roof sheet  280  along each of the first side  288  and the second side  290 . In other embodiments, for example, the outer angle assembly  304  and/or the inner angle assembly  306  may not be segmented but formed as a unitary support. 
     A gasket  316  is arranged under the inner angle assembly  306  and is configured to provide a seal between an upper end of each of the first end wall  204 , the second end wall  206 , the first side wall  208 , and the second side wall  210  and the roof  212 , as will be described. The gasket  316  may be fabricated from segmented portions, or may be fabricated from as a unitary component. The gasket  316  may be fabricated from a rubber material (e.g., ethylene propylene diene monomer). 
     It should be appreciated that the roof  212  is symmetric about a central longitudinal axis CL (see  FIG. 29 ). Therefore, the following description of the configuration of the roof  212  and the upper end  336  of the second side wall  210  symmetrically applies to the roof  212  and the upper end of the first side wall  208 . As such, similar components are identified using like reference numerals in the figures. Turning to  FIGS. 33 and 34 , the outer side angle support  313  defines a generally L-shaped profiled and includes an outer top portion  318  and an outer side portion  320 . The outer top portion  318  is arranged generally parallel to the top surface  300  of the roof sheet  280 . The outer side portion  320  extends down along the second side  290  of the roof  212  and is arranged substantially perpendicularly to the top surface  300  of the roof sheet  280 . The inner side angle support  315  defines a generally L-shaped profile and includes an inner top portion  322  and an inner side portion  324 . The inner top portion  322  is arranged generally parallel to the top surface  300  of the roof sheet  280 . The inner side portion  324  extends downward from the inner top portion  322  and is arranged substantially perpendicularly to the top surface  300  of the roof sheet  280 . 
     The roof sheet  280  extends under the skid plate assembly  282  and over the outer top portion  318  and the outer side portion  320  of the outer side angle support  313 . The outer side portion  320  extends down along the second side  290  of the roof  212  further than the inner side portion  324 . A fastening element  326  extends through the skid plate  298 , the roof sheet  280 , and the outer side portion  320  at a location adjacent to a bottom end  328  of the second side  290  of the roof  212 . The illustrated fastening element  326  is in the form of a rivet; however, other types of fastening mechanisms may be implemented. A plurality of the fastening elements  326  are arranged longitudinally along the bottom end  328  of the second side  290  to fasten the roof sheet  280  to the second side  290  of the roof  212 . 
     The inner side portion  324  of the inner side angle support  315  engages the outer side portion  320  of the outer side angle support  313  on a side opposite of the roof sheet  280  and at a location between the fastening elements  326  and the outer top portion  318 . The inner side portion  324  of the inner side angle support  315  is fastened to the outer side portion  320  of the outer side angle support  313  by a fastening element  330 . The illustrated fastening element  330  is in the form of a countersunk rivet; however, other types of fastening mechanisms may be implemented. The fastening element  330  is countersunk into the outer side portion  320  and extends through the inner side portion  324 . A plurality of the fastening elements  330  are arranged longitudinally along the second side  290  to fasten the outer side angle support  313  to the inner side angle support  315 . 
     An end of the each roof bow  302  is secured between the outer top portion  318  and the inner top portion  322 . The end of each roof bow  302  is fastened to a distal end  333  of the inner top portion  322  of the inner side angle support  315  via a fastening element  331  (best illustrated in  FIG. 35 ). One of the fastening elements  331  fastens each end of each roof bow  302  to one of the pair of inner side angle supports  315 . The fastening elements  331  are in the form of rivets; however, other fastening mechanisms may be implemented. 
     With continued reference to  FIGS. 33 and 34 , the inner top portion  322  extends inward, away from the second side  290 , a further distance than the outer top portion  318 . The gasket  316  is attached to the inner top portion  322  opposite the roof bow  302 . The gasket  316  extends longitudinally along the entirety of the inner top portion  322  of the inner side angle support  315  (as best shown in  FIG. 35 ). A distal end  333  of the inner top portion  322  is in engagement with and removably coupled to an side wall bracket  332 . The side wall bracket  332  is configured to engage a side wall extension  334 . The side wall extension  334  extends longitudinally along the entire upper end  336  of the second side wall  210 . The side wall extension  334  is coupled to the upper end  336  of the second side wall  210  by a fastening element  338 . The illustrated fastening element  338  is in the form of a rivet; however, other types of fastening mechanisms may be implemented. A plurality of the fastening elements  338  extend along the upper end  336  of the second side wall  210  to fasten the side wall extension  334  to the upper end  336  of the second side wall  210 . 
     The side wall extension  334  extends from the upper end  336  of the second side wall  210  toward the gasket  316  and includes a generally hook, or U-shaped, portion  340 . The hook portion  340  extends past the upper end  336  of the second side wall  210  and hooks inward toward an internal cavity  342  defined within the modular shipping container  200 , when assembled. The hook portion  340  includes a seal surface  344  that is arranged generally parallel to the inner top portion  322  of the inner side angle support  315 . The seal surface  344  engages the gasket  316  to form a seal between therebetween. As described above, the roof sheet  280  is fabricated as a unitary component, which may eliminate any seams formed thereon and thereby may reduce the chance of a leak in the roof  212 . The combination of the roof sheet  280  and the seal formed between the side wall extension  334  and the gasket  316  of the roof  212  aid in isolating the internal cavity  342  of the modular shipping container  200  from the outside. This helps reduce or prevent leak paths from forming through the roof  212 , or at the junction between the roof  212  and the second side wall  210 . In addition, the roof sheet  280 , the skid plate  298 , and the outer side portion  320  extend below the seal formed between the gasket  316  and the side wall extension  334 , which help shield the seal, for example, from rain fall. 
     The distal end  333  of the inner top portion  322  of the inner side angle support  315  is removably coupled to the side wall bracket  332  by a fastening element  346 . The illustrated fastening element  346  is in the form of a bolt and nut; however, other removable coupling mechanisms may be implemented. The side wall bracket  332  is configured to engage the hook portion  340  of the side wall extension  334 . In this way, as the fastening element  346  is tightened, the gasket  316  is compressed between the seal surface  344  of the side wall extension  334  and the inner top portion  322  of the inner side angle support. 
     A plurality of the side wall brackets  332  may be arranged along the side wall extension  334  to removably couple the second side wall  210  to the roof  212 . As shown in  FIG. 35 , the illustrated side wall extension  334  includes five side wall brackets  332  spaced longitudinally along the side wall extension  334 . In other embodiments, for example, the side wall extension  334  may include more or less than five side wall brackets  332 . The side wall brackets  332  are removably coupled to the inner side angle support  315  to enable the roof  212  to be attached and detached from the second side wall  210 , as desired. That is, during assembly of the modular shipping container  200 , once each of the first end wall  204 , the second end wall  206 , the first side wall  208 , and the second side wall  210  are erected, the roof  212  can be placed over the upper end  336  of the second side wall  210  such that the gasket  316  engages the seal surface  344 . The seal surface  344  may partially compress the gasket  316  between the inner side angle support  315  and the seal surface  344  to form the seal therebetween, and the side wall brackets  332  may be coupled to the inner side angle support  315  to secure the second side wall  210  to the roof  212 . The side wall brackets  332  may be un-coupled from the inner side angle support  315  to enable the modular shipping container  200  to be disassembled, as will be described below. 
     It should be appreciated that the roof  212  is symmetric about a central axis CR arranged perpendicular to the central longitudinal axis CL. Therefore, the following description of the configuration of the roof  212  and the upper end  374  of the first end wall  204  symmetrically applies to the roof  212  and the upper end of the second end wall  206 . As such, similar components are identified using like reference numerals in the figures. Turning to  FIGS. 36 and 37 , the outer end angle support  312  defines a generally L-shaped profiled and includes an outer end top portion  350  and an outer end side portion  352 . The outer end top portion  350  is arranged generally parallel to the top surface  300  of the roof sheet  280 . The outer end side portion  352  extends down along the first end  284  of the roof  212  and is arranged substantially perpendicularly to the top surface  300  of the roof sheet  280 . The inner end angle support  314  defines a generally L-shaped profile and includes an inner end top portion  354  and an inner end side portion  356 . The inner end top portion  354  is arranged generally parallel to the top surface  300  of the roof sheet  280 . The inner end side portion  356  extends downward from the inner end top portion  354  and is arranged substantially perpendicularly to the top surface  300  of the roof sheet  280 . 
     The roof sheet  280  extends over the outer end top portion  350  and the outer end side portion  352  of the outer end angle support  312 . The outer end side portion  352  extends down along the first end  284  of the roof  212  further than the inner end side portion  356 . A fastening element  358  extends through an attachment strip  360 , the roof sheet  280 , and the outer end side portion  352  at a location adjacent to a bottom end  362  of the first end  284  of the roof  212 . The attachment strip  360  extends along the first end  284  of the roof  212  between the first skid end caps  292  arranged thereon. The illustrated fastening element  358  is in the form of a rivet; however, other types of fastening mechanisms may be implemented. A plurality of the fastening elements  358  are arranged longitudinally along attachment strip  360  and the first skid end caps  292  to fasten the roof sheet  280  to the first end  284  of the roof  212 . 
     The inner end side portion  356  of the inner end angle support  314  engages the outer end side portion  352  of the outer end angle support  312  on a side opposite of the roof sheet  280  and at a location between the fastening elements  358  and the outer end top portion  350 . The inner end side portion  356  of the inner end angle support  314  is fastened to the outer end side portion  352  of the outer end angle support  312  by a fastening element  364 . The illustrated fastening element  364  is in the form of a countersunk rivet; however, other types of fastening mechanisms may be implemented. The fastening element  364  is countersunk into the outer end side portion  352  and extends through the inner end side portion  356 . A plurality of the fastening elements  364  are arranged along the first end  284  to fasten the outer end angle support  312  to the inner side angle support  314 . 
     The outer end top portion  350  extends partially over the illustrated one of the plurality of roof bows  302  arranged adjacent to the first end  284 . Specifically, the outer end top portion  350  extends over one of the bow flanges  310  arranged adjacent to the first end  284  of the roof  212 . 
     With continued reference to  FIGS. 36 and 37 , the inner end top portion  354  extends inward, away from the first end  284 , a distance farther than the outer end top portion  350 . The gasket  316  is attached to the inner end top portion  354  opposite the roof bow  302 . The gasket  316  extends longitudinally along the entirety of the inner end top portion  354  of the inner end angle support  314 . A distal end  368  of the inner end top portion  354  is in engagement with and removably coupled to an end wall bracket  370 . The end wall bracket  370  is configured to engage an end wall extension  366 . The end wall extension  366  extends along the entire upper end  374  of the first end wall  204 . The end wall extension  366  is coupled to the upper end  374  of the first end wall  204  by a fastening element  376 . The illustrated fastening element  376  is in the form of a rivet; however, other types of fastening mechanisms may be implemented. A plurality of the fastening elements  376  are arranged along the upper end  374  of the first end wall  204  to fasten the end wall extension  366  to the upper end  374  of the first end wall  204 . 
     The end wall extension  366  extends from the upper end  374  of the first end wall  204  toward the gasket  316  and includes a generally hook, or U-shaped, portion  378 . The hook portion  378  extends past the upper end  374  of the first end wall  204  and hooks inward toward the internal cavity  342 . The hook portion  378  includes a seal surface  380  that is arranged generally parallel to the inner end top portion  354  of the inner end angle support  314 . The seal surface  380  engages the gasket  316  to form a seal between therebetween. As described above, the roof sheet  280  is fabricated as a unitary component, which may reduce or eliminate seams formed thereon and thereby may reduce the chance of a leak in the roof  212 . The combination of the roof sheet  280  and the seal formed between the end wall extension  366  and the gasket  316  of the roof  212  aid in isolating the internal cavity  342  of the modular shipping container  200  from the outside. This may reduce or prevent leak paths from forming through the roof  212 , or at the junction between the roof  212  and the first end wall  204 . In addition, the roof sheet  280 , the attachment strip  360 , and the outer end side portion  352  extend below the seal formed between the gasket  316  and the end wall extension  366 , which help shield the seal, for example, from rain fall. 
     The distal end  368  of the inner end top portion  354  of the inner end angle support  314  is removably coupled to the end wall bracket  370  by a fastening element  382 . The illustrated fastening element  382  is in the form of a bolt and nut; however, other removable coupling mechanisms may be implemented. The end wall bracket  370  is configured to engage the hook portion  378  of the end wall extension  366 . In this way, as the fastening element  382  is tightened, the gasket  316  is compressed between the seal surface  380  of the end wall extension  366  and the inner end top portion  354  of the inner end angle support  314 . 
     As shown in  FIG. 38 , the illustrated end wall extension  366  includes one end wall bracket  370  generally centered along the upper end  374  of the first end wall  204 . In other embodiments, for example, the end wall extension  366  may include more or less than one end wall bracket  370 . The end wall bracket  370  is removably coupled to the inner end angle support  314  to enable the roof  212  to be attached and detached from the first end wall  204 , as desired. That is, during assembly of the modular shipping container  200 , once each of the first end wall  204 , the second end wall  206 , the first side wall  208 , and the second side wall  210  are erected, the roof  212  can be placed over the upper end  374  of the first end wall  204  such that the gasket  316  engages the seal surface  380 . The seal surface  380  may partially compress the gasket  316  between the inner end angle support  314  and the seal surface  380  to form the seal therebetween, and the end wall bracket  370  may be coupled to the inner end angle support  314  to secure the first end wall  204  to the roof  212 . The end wall bracket  370  may be un-coupled from the inner end angle support  314  to enable the modular shipping container  200  to be disassembled, as will be described below. 
     The design and configuration of the above-described roof  212  for the modular shipping container  200  provides the unitary roof sheet  280  without any seams formed therein. Additionally, the roof  212  is provided with a gasket  316  configured to provide a seal between the upper ends of each of the first end wall  204 , the second end wall  206 , the first side wall  208  and the second side wall  210 , when the modular shipping container  200  is assembled. Further, the roof  212  is removably coupled to each of the first end wall  204 , the second end wall  206 , the first side wall  208  and the second side wall  210  to enable assembly and disassembly of the modular shipping container  200 , as desired. It should be appreciated that the above-described characteristics and properties of the roof  212  are not limited to use with the modular shipping container  200 , and may be applied to any shipping container. 
       FIGS. 39-41  illustrate the pivotal coupling of the first side wall  208  and the second side wall  210  to the base  202  of the modular shipping container  200 . As described above, the first end rail  220  includes the first stationary hinge pin assembly  244  attached to the distal end  236  and the stationary second hinge pin assembly  246  attached to the opposing distal end  240 . As shown in  FIG. 40 , the first side wall  208  includes a first side tube hinge  384  attached to a bottom end  386  thereof. The first side tube hinge  384  extends longitudinally along the bottom end  386  of the first side wall  208 , which may increase a rigidity of the first side wall  208 . The first side tube hinge  384  defines a generally hollow tube with a generally rectangular profile, although other profiles may be utilized. 
     The first stationary hinge pin assembly  244  is configured to interact with the first side tube hinge  384  to enable a pivotal coupling between the first side wall  208  and the base  202 . The first stationary hinge pin assembly  244  defines a general L-shape and includes an attachment portion  388  and a flange portion  390 . The attachment portion  388  is attached to the distal end  236  of the first end rail  220  and is arranged generally parallel to the floor  214  of the base  202 . The flange portion  390  extends upward substantially perpendicularly from the attachment portion  388 . The flange portion  390  includes a coupling aperture  392  arranged therein. The coupling aperture  392  is configured to receive a fastening element  394  to removably couple the first stationary hinge pin assembly  244  to one of a plurality of retainer flanges  396 . 
     A pivot pin  397  is attached to the first stationary hinge pin assembly  244  and extends therefrom. The pivot pin  397  is attached to the first stationary hinge pin assembly  244  adjacent to a junction between the attachment portion  388  and the flange portion  390 . The pivot pin  397  extends from the first stationary hinge pin assembly  244  in a direction away from the first end wall  204  and is configured to be received within the first side tube hinge  384  of the first side wall  208 . The arrangement of the pivot pin  397  within the first side tube hinge  384  enables the pivotal rotation of the first side wall  208  during assembly and disassembly of the modular shipping container  200 , as will be described. 
     Turning to  FIGS. 41A and 41B , the second side wall  210  includes a second side tube hinge  398  and a shim tube  400  each attached to a bottom end  402  thereof. Each of the second side tube hinge  398  and the shim tube  400  extends longitudinally along the bottom end  402  of the second side wall  210 , which may increase a rigidity of the second side wall  210 . The second side tube hinge  398  defines a generally hollow tube with a generally rectangular profile. The shim tube  400  defines a generally hollow tube with a generally rectangular profile. The second side tube hinge  398  is coupled to and arranged above the shim tube  400 . That is, the shim tube  400  is arranged between the second side tube hinge  398  and the base  202 . 
     The second stationary hinge pin assembly  246  is configured to interact with the second side tube hinge  398  to enable a pivotal coupling between the second side wall  210  and the base  202 . The second stationary hinge pin assembly  246  defines a general L-shape and includes an attachment portion  404  and a flange portion  406 . The attachment portion  404  is attached to the distal end  240  of the first end rail  220  and is arranged generally parallel to the floor  214  of the base  202 . The flange portion  406  extends upward substantially perpendicularly from the attachment portion  404 . The flange portion  406  includes a coupling aperture  408  arranged therein. The coupling aperture  408  is configured to receive a fastening element  410  to removably couple the second stationary hinge pin assembly  246  to one of a plurality of retainer flanges  396 . 
     A pivot pin  412  is attached to the second stationary hinge pin assembly  246  and extends therefrom. The pivot pin  412  is attached to the second stationary hinge pin assembly  246  on the flange portion  390 . The pivot pin  412  extends from the second stationary hinge pin assembly  246  in a direction away from the first end wall  204  and is configured to be received within the second side tube hinge  398  of the second side wall  210 . The arrangement of the pivot pin  412  within the second side tube hinge  398  enables the pivotal rotation of the second side wall  210  during assembly and disassembly of the modular shipping container  200 , as will be described. 
     As described above, the second end rail  222  includes the plurality of first hinge apertures  248  arranged within the distal end  238  and the plurality of second hinge apertures  250  arranged within the distal end  242 . Turing to  FIGS. 42-45 , the first stationary hinge pin assembly  244  is configured to cooperate with a first removable hinge pin assembly  414 . The first removable hinge pin assembly  414  is configured to be removably attached to the second end rail  222  via a plurality of fastening elements (not shown) extending through a corresponding one of a plurality of mounting apertures  416  arranged within the first removable hinge pin assembly  414  and into the plurality of first hinge apertures  248 . The first removable hinge pin assembly  414  is configured to interact with the first side tube hinge  384  to enable a pivotal coupling between the first side wall  208  and the base  202 . The removable first hinge pin assembly  414  defines a general L-shape and includes an attachment portion  418  and a flange portion  420 . The attachment portion  418  includes the plurality of mounting apertures  416  and is arranged generally parallel to the floor  214  of the base  202 , when assembled. The flange portion  420  extends upward substantially perpendicularly from the attachment portion  418 . The flange portion  420  includes a coupling aperture  422  arranged therein. The coupling aperture  422  is configured to receive a fastening element (not shown) to removably couple the removable first hinge pin assembly  414  to one of a plurality of retainer flanges  396  (best shown in  FIG. 20 ), when assembled. 
     A pivot pin  424  is attached to the removable first hinge pin assembly  414  and extends therefrom. The pivot pin  424  is attached to the removable first hinge pin assembly  414  adjacent to a junction between the attachment portion  418  and the flange portion  420 . The pivot pin  424  extends from the removable first hinge pin assembly  414  in a direction away from the second end wall  206 , when assembled, and is configured to be received within the first side tube hinge  384  of the first side wall  208 . The receipt of the pivot pin  397  of the first stationary hinge pin assembly  244  and the pivot pin  424  of the removable first hinge pin assembly  414  within the first side tube hinge  384  defines a first pivot axis P 1 , and enables the pivotal rotation of the first side wall  208  during assembly and disassembly of the modular shipping container  200 . It should be appreciated that the stationary nature (i.e., the permanent attachment) of the first stationary hinge pin assembly  244  is not meant to be limiting in any way and, in other non-limiting examples, for example, it may be removably coupled to the first end rail  220 . The illustrated first stationary hinge pin assembly  244  and first removable hinge pin assembly  414  are provided with one stationary component and one removable component for ease of manufacture. For example, when manufacturing the modular shipping container  200 , the first side tube hinge  384  of the first side wall  208  may first be slid over the pivot pin  397  of the first stationary hinge pin assembly  244 . Then, the pivot pin  424  of the first removable hinge pin assembly  414  may be placed within the first side tube hinge  384  by the manufacturer and subsequently coupled to the second end rail  222  of the base  202 . 
     The second stationary hinge pin assembly  246  is configured to cooperate with a second removable hinge pin assembly  426 . The second removable hinge pin assembly  426  is configured to be removably attached to the second end rail  222  via a plurality of fastening elements (not shown) each extending through a corresponding one of a plurality of mounting apertures  428  arranged within the second removable hinge pin assembly  426  and into the plurality of second hinge apertures  250 . The second removable hinge pin assembly  426  is configured to interact with the second side tube hinge  398  to enable a pivotal coupling between the second side wall  210  and the base  202 . The second removable hinge pin assembly  426  defines a general L-shape and includes an attachment portion  430  and a flange portion  432 . The attachment portion  430  includes the plurality of mounting apertures  428  and is arranged generally parallel to the floor  214  of the base  202 , when assembled. The flange portion  432  extends upward substantially perpendicularly from the attachment portion  430 . The flange portion  432  includes a coupling aperture  434  arranged therein. The coupling aperture  434  is configured to receive a fastening element (not shown) to removably couple the second removable hinge pin assembly  426  to one of a plurality of retainer flanges  396  (best shown in  FIG. 20 ), when assembled. 
     A pivot pin  436  is attached to the second removable hinge pin assembly  426  and extends therefrom. The pivot pin  436  is attached to the second removable hinge pin assembly  426  on the flange portion  432 . The pivot pin  436  extends from the second removable hinge pin assembly  426  in a direction away from the second end wall  206 , when assembled, and is configured to be received within the second side tube hinge  398  of the second side wall  210 . The receipt of the pivot pin  412  of the second stationary hinge pin assembly  246  and the pivot pin  436  of the second removable hinge pin assembly  426  within the second side tube hinge  398  defines a second pivot axis P 2 , and enables the pivotal rotation of the second side wall  210  during assembly and disassembly of the modular shipping container  200 . It should be appreciated that the stationary nature (i.e., the permanent attachment) of the second stationary hinge pin assembly  246  is not meant to be limiting in any way and, in other non-limiting examples, for example, it may be removably coupled to the first end rail  220 . The illustrated second stationary hinge pin assembly  246  and second removable hinge pin assembly  426  are provided with one stationary component and one removable component for ease of manufacture. For example, when manufacturing the modular shipping container  200 , the second side tube hinge  398  of the second side wall  210  may first be slid over the pivot pin  412  of the second stationary hinge pin assembly  246 . Then, the pivot pin  436  of the second removable hinge pin assembly  426  may be placed within the second side tube hinge  398  by the manufacturer and subsequently coupled to the second end rail  222  of the base  202 . 
     The pivot pins  412  and  436  of the second stationary hinge pin assembly  246  and the second removable hinge pin assembly  426  are arranged higher (i.e., on the respective flange portions  390  and  432 ), when compared to the pivot pins  397  and  424  of the first stationary hinge pin assembly  244  and the first removable hinge pin assembly  414 . Thus, the pivot axis P 2  defined by the second side wall  210  is arranged higher, relative to the floor  214 , when compared to the pivot axis P 1  defined by the first side wall  208 . 
     When the modular shipping container  200 , is in a disassembled state, the first side wall  208  is pivoted such that the first side wall  208  lays on the floor  214  (i.e., the first side wall  208  is in engagement with and arranged substantially parallel to the floor  214 ). In this position, the first side wall  208  defines a height from the floor  214 . The raised height, relative to the floor  214 , defined by the second pivot axis P 2  ensures that the second side wall  210 , when pivoted toward the floor  214  to disassemble the modular shipping container  200 , lays flat on the first side wall  208  (i.e., in engagement with the first side wall  208  and arranged substantially parallel to the floor  214 ). In this manner, a shipping height defined by the modular shipping container  200  (i.e., a height defined by the modular shipping container  200  in a disassembled state) is minimized. 
     Assembly and disassembly of the modular shipping container  200  will be described with reference to  FIGS. 46A-47D . The modular shipping container  200  may be shipped to an end user in a disassembled, or collapsed, state, also known as kit form. In the disassembled state ( FIG. 47A ), the roof  212  is de-coupled from the first and second end walls  204  and  206 , and the first and second side walls  208  and  210  by removal of the fastening elements  346  and  382 . With the roof  212  de-coupled from the modular shipping container  200 , the first side wall  208  is pivoted toward the floor  214  until the first side wall  208  engages the floor  214  and is arranged substantially parallel thereto. The pivotal coupling between the first stationary and removable hinge pin assemblies  244  and  414  and the first side tube hinge  384  enables first side wall  208  to easily pivot toward the floor  214  about the first pivot axis P 1 . Subsequently, the second side wall  210  is pivoted toward the floor  214  until the second side wall  210  engages the first side wall  208  and is arranged substantially parallel thereto. The pivotal coupling between the second stationary and removable hinge pin assemblies  246  and  426  and the second side tube hinge  398  enables the second side wall  210  to easily pivot toward the floor  214  about the second pivot axis P 2 . 
     Once the first and second side walls  208  and  210  are pivoted down to the floor  214 , the first end wall  204  and the second end wall  206  are de-coupled from the base  202  and placed on top of the second side wall  210 . The first and second end walls  204  and  206  are dimensioned to lay flat on the second side wall  210 , as shown in  FIG. 47A . Lastly, the roof  212  is placed on top of the first end wall  204  and the second end wall  206 . Thus, the modular shipping container  200  is collapsible into a disassembled state. In the disassembled state, the modular shipping container  200  defines a drastically reduced volume, when compared to the assembled state, for ease of transport. Further, one or more additional modular shipping containers  200  may be stacked on top of one another to enable the compact shipment of multiple modular shipping containers  200  to an end user. 
     When an end user receives a modular shipping container  200 , in the disassembled state, the design of the modular shipping container  200  enables the end user to easily assemble the modular shipping container  200  on site. Initially, the roof  212  is removed from the disassembled modular shipping container  200  to enable erection of the first and second end walls  204  and  206  and the first and second side walls  208  and  210 . Once the roof  212  is removed, the first and second end walls  204  and  206  are erected and coupled to the first and second end rails  220  and  222  of the base  202 , respectively, as shown in  FIG. 47B . With the first and second end walls  204  and  206  erected, the second side wall  210  is erected by pivotally rotating it about the second pivot axis P 2 . As shown in  FIGS. 47A-D , each of end of the first and second end walls  204  and  206  include one of the plurality of retainer flanges  396  attached thereto. A longitudinally opposed pair of the plurality of retainer flanges  396  adjacent to the second side rail  226  act as a stop for the second side wall  210  as it is erected. That is, the second stationary and removable hinge pin assemblies  246  and  426  and the second side tube hinge  398  enable the second side wall  210  to pivotally rotate until the second side wall  210  engages the respective pair of the retainer flanges  396 . Thus, the second side wall  210  is pivotally rotated about the second pivot axis P 2  until the second side wall  210  is aligned in its final, erected position. Once in the final position, the second side wall  210  may be coupled, for example, via a plurality of bolts and nuts, to the pair of retainer flanges  396  and the base  202  to secure the second side wall  210  in its final position. 
     As shown in  FIG. 47C , once the second side wall  210  is erected in its final position, the first side wall  208  is erected by pivotally rotating it about the first pivot axis P 1 . As shown in The other longitudinally opposed pair of the plurality of retainer flanges  396  adjacent to the first side rail  224  act as a stop for the first side wall  208  as it is erected. That is, the first stationary and removable hinge pin assemblies  244  and  414  and the first side tube hinge  384  enable the first side wall  208  to pivotally rotate until the first side wall  208  engages the respective pair of the retainer flanges  396 . Thus, the first side wall  208  is pivotally rotated about the first pivot axis P 1  until the first side wall  208  is aligned in its final, erected position. Once in the final position, the first side wall  208  may be coupled, for example, via a plurality of bolts and nuts, to the pair of retainer flanges  396  and the base  202  to secure the first side wall  208  in its final position, thereby completing the modular container assembly  200 , as shown in  FIG. 47D . 
     As described above, one or more modular shipping containers  200  may be stacked on top of one another to enable the compact shipment of multiple modular shipping containers  200  to an end user.  FIG. 48  illustrates a plurality of the modular shipping container  200  stacked on top of one another for shipment to an end user. The illustrated plurality of the modular shipping containers  200  includes six of the modular shipping containers  200 ; however, this is not meant to be limiting in any way, and any number of the modular shipping containers  200  may be stacked upon one another. The plurality of the modular shipping containers  200  are held in a stacked state using a plurality of stacking brackets  440 . The plurality of stacking brackets  440  are dimensioned to engage and support a pair of first stacking tubes  442  extending from the first end rail  220  and a pair of second stacking tubes  444  extending from the second end rail  222 . 
     As shown in  FIGS. 49 and 50 , each of the plurality of stacking brackets  440  include a horizontal stacking tube  446  and a vertical stacking tube  448  coupled to the horizontal stacking tube  446 . The horizontal stacking tubes  446  are dimensioned to be received within a corresponding one of the first stacking tubes  442  and the second stacking tubes  444  of the base  202 . An end  450  of the vertical stacking tube  448 , extending away from the horizontal stacking tube  446 , includes a stacking post  452  extending therefrom. The stacking post  452  extends from inside the end  450  of the vertical stacking tube  448  and is dimensioned to receive a stacking adapter  454 . The stacking adapters  454  are dimensioned to couple the end  450  of one stacking bracket  440  to an opposing end  458  of another stacking bracket  440 . In this way, a plurality of stacking brackets  440  may be stacked on one another to form a stacking assembly  460 . Each respective stacking bracket  440  in the stacking assembly  460  includes a horizontal stacking tube  446  received within a corresponding one of the pair of first stacking tubes  442  or one of the pair of second stacking tubes  444 . Since the modular shipping container  200  includes the pair of first stacking tubes  442  arranged on the first end rail  220  and the pair of second stacking tubes  444  arranged on the second end rail  222 , four of the stacking assemblies  460  may be utilized when stacking the plurality of the modular shipping containers  200 . 
     Straps  462  may be used to secure the roof  212  to the rest of the modular shipping container  200  in the disassembled state. The straps  462  extend through a respective one of the fork tunnels  254  and around the roof  212  thereby securing the roof  212  to the rest of the modular shipping container  200 , when disassembled. 
     The design and properties of the modular shipping container  200  reduce a shipping height defined by the modular shipping container  200  in a disassembled state, or a kit form. Additionally, the modular shipping container  200  enables an end user to assemble the modular shipping container  200  on site. It should be appreciated that the properties and functionality of the first stationary and removable hinge pin assemblies  244  and  414 , the second stationary and removable hinge pin assemblies  246  and  426 , the first side tube hinge  384 , and the second side tube hinge  398  are not limited to the modular shipping container  200 , and may be applied to other shipping containers. 
     It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. 
     Various features and advantages of the invention are set forth in the following claims.