Patent Publication Number: US-6988781-B2

Title: Airtight blast resistant cargo container

Description:
FIELD OF THE INVENTION 
   The present invention pertains generally to load containment devices. More particularly, the present invention pertains to cargo containers that will resist the blast effect of an explosive detonation inside the cargo container. The present invention is particularly, but not exclusively, useful for containing luggage and other cargo during transport by aircraft. 
   BACKGROUND OF THE INVENTION 
   Aircraft are attractive targets for political terrorists. Specifically, terrorists have placed bombs aboard aircraft to murder passengers and crewmembers that are also aboard the aircraft, and to cause further damage to persons and structures on the ground. This form of terrorist act often provokes an intense public reaction that has a substantial political impact. 
   Despite the use of extremely tight security procedures and sophisticated explosive detecting equipment, terrorists have still been able to place bombs aboard aircraft. One method used by terrorists to place a bomb aboard an aircraft is to hide the bomb in a passenger&#39;s luggage or in other items that are stored and carried in the cargo compartment of the aircraft. Terrorists have been able to use this method because small bombs cannot be easily detected through ordinary screening methods. One approach to solving this problem is to institute elaborate and intrusive screening methods. Another way to deal with this problem is to mitigate the potential damage that could be caused by a small bomb detonating aboard the aircraft. 
   In the airline industry, it is a standard practice to place cargo into a containment device, which is commonly referred to as Unit Load Devices (ULDs). The shape, size and weight of a ULD for a given type aircraft has been fairly well standardized due to practical considerations and regulatory requirements. Consequently, a typical ULD is in the shape of a box having sloped surfaces that conform the ULD to the aircraft&#39;s fuselage when the ULD is placed in the aircraft&#39;s cargo compartment. The ULD is often made of several panels, which are joined together at their edges to surround a cargo hold. Additionally, the ULD has an opening to provide access to the cargo hold, and a door for covering the opening. Cargo is placed into, or removed from, the cargo hold through the opening. 
   A ULD designed to withstand an explosive blast in the cargo hold should also conform to these practical considerations and regulatory requirements. Additionally, a blast resistant ULD may include other structures, or be formed from particular materials, to resist an explosive blast. For example, the panels in a blast resistant ULD may be structured to resist tensile stresses that are directed toward the plane of the panel. In response to an internal explosion, these panels tend to bulge outwardly from the explosive source but are effective in resisting rupture. 
   Stress analysis performed on existing ULDs show that the highest tension stress concentrations caused by an explosive blast within the cargo hold will occur at the edges where the panels have been joined together and at the door around the opening. Consequently, more material is often added to ULDs at these points of highest tension stress concentration to better contain an internal explosion. This additional material, however, adds cost and additional weight to the ULD, and may reduce the size of the cargo hold. 
   In light of the above, it is an object of the present invention to provide a containment device that is able to resist an internal explosive blast without rupturing the device. Another object of the present invention is to provide a containment device that reduces tension stress concentrations caused by an internal explosive blast. Yet another object of the present invention is to provide a containment device that meets the regulatory standards for the use of such devices in air transport operations. Still another object of the present invention is to provide a containment device that allows relatively easy access to a cargo hold located inside the cargo container. Another object of the present invention is to provide a containment device that is easy to use, relatively easy to manufacture, and comparatively cost effective. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, an explosion resistant containment device is provided for containing luggage and other cargo during air transport. The device includes a container formed by joining panels in a unitary construction to reduce tension stress concentrations on the container that may be caused by an explosive denotation in the cargo hold. Additionally, the container includes interior surfaces surrounding a cargo hold. The interior surfaces include a top surface and a bottom surface that are substantially parallel to each other, a back surface and a front surface that are substantially parallel to each other, and a left surface and a right surface that are substantially parallel to each other. 
   The container also includes an opening defined by an edge for providing access to the cargo hold. A flange extends inwardly from the edge of the opening to establish a seat between the flange and the portion of the container surrounding the opening. The flange is continuous with the portion of the container surrounding the opening and is part of the unitary construction of the container. 
   An internally retracting door for covering the opening includes a substantially flat door panel having a front side circumscribed by edges forming a border. The edges of the door panel are substantially perpendicular to the front side of the door panel. Additionally, the door includes a bite on the front side of the panel at the border, which extends away from the front side of the panel in a substantially perpendicular direction. A core formed in the bite may be either hollow or solid. The door is dimensioned so that the bite can be juxtaposed with the flange to cover the opening with the panel when the bite is positioned against the seat. Furthermore, the panel and the bite are constructed with a composite material having a high strength to weight ratio. 
   The door also includes one or more handles mounted to the front side of the panel, and may include one or more handles mounted to edges of the door. The handles can be used for moving the door while opening and closing the door. When the door is being opened, the door retracts into the interior of the container. When the door is being closed, the door is retrieved from the interior of the container and the bite is positioned against the seat to cover the opening with the door panel. Additionally, the flange and the bite each have a number of corresponding bolt holes that line up with each other when the bite is positioned against the seat. When the bite is positioned against the seat, a bolt may be inserted into each pair of corresponding bolt holes to hold the door over the opening. 
   As a result of an explosive detonation in the cargo hold, an explosive force is exerted against the door panel and the container. The explosive force is transferred from the door panel to the bite and subsequently to the container at the seat. Optionally, a seal may be affixed to the seat. If used, the seal will transfer the explosive force to the container at the seat. Additionally, the bite minimizes door warping that may be caused by the explosive force on the door. 
   When used, the seal establishes an air-tight lock between the bite and the container in response to an internal pressure in the cargo container. Specifically, an explosion in the cargo hold creates sufficient internal pressure in the interior of the cargo container to press the bite against the seal to form the airtight lock. When the container is sealed, gasses are prevented from escaping the cargo hold and gasses are also prevented from entering the cargo hold. 
   In one embodiment of the containment device, a top cradle is mounted to the top surface of the container and a bottom cradle is mounted to the bottom surface of the container. The door is positioned between the top cradle and the bottom cradle to guide the door while the door is being opened or closed. Additionally, the bottom cradle includes a plate for supporting the door. 
   In an alternate embodiment of the containment device, the door includes a right surface and a left surface that are substantially parallel to each other. Axels are mounted to the left and right edges of the door and rollers are mounted to the axels. Additionally, guide rails are mounted to the left and right sides of the container to guide the rollers while the door is being opened or closed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: 
       FIG. 1  is a perspective view of a device according to the present invention, with a portion broken away for clarity; 
       FIG. 2  is a perspective view of a door used in the device shown in  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of the door as seen along the line  3 — 3  in  FIG. 2 ; 
       FIG. 4  is a cross-sectional view of a portion of the device as seen along the line  4 — 4  in  FIG. 1 , showing the door secured in the container, with portions broken away for compactness and clarity; 
       FIG. 5  is a cross-sectional view of the device as seen along the line  5 — 5  in  FIG. 1 ; 
       FIG. 6  is a cross-sectional view of the device as seen along the line  5 — 5  in  FIG. 1 , showing the door fully retracted into the cargo hold; 
       FIG. 7  is a cross-sectional view of the device as seen along the line  7 — 7  in  FIG. 1 ; 
       FIG. 8  is a perspective view of the bottom cradle shown in  FIGS. 5 ,  6  and  7 ; 
       FIG. 9  is a perspective view of the top cradle shown in  FIG. 7 ; 
       FIG. 10  is a perspective view of a door used in the device shown in  FIG. 1 ; 
       FIG. 11  is a cross-sectional view of the device as seen along the line  5 — 5  in  FIG. 1 ; and 
       FIG. 12  is a cross-sectional view of the device as seen along the line  7 — 7  in  FIG. 1 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring initially to  FIG. 1 , the explosion resistant containment device of the present invention is shown and is generally designated  14 . The containment device  14  includes a container  15 , which is formed with an opening  16 . Preferably, the container  15  is constructed with a plurality of substantially flat panels, which are joined at their peripheries where the panels intersect each other to surround a cargo hold  17 . Exemplary panels for the container  15  include a top panel  18 , a bottom panel  20 , a left panel  22 , a right panel  24 , a front panel  26  and a back panel  28 . Preferably, the container  15  is formed with a composite material in a unitary construction to maximize the overall structural strength of the container  15 . Specifically, the unitary construction reduces the likelihood of tension stress concentration on the joints between the panels  18 ,  20 ,  22 ,  24 ,  26  and  28 . Moreover, the composite material used for the construction of the container  15  should exhibit a high strength to weight ratio to resist an internal blast, contain fragments and prevent shock holing. For example, SPECTRA and KEVLAR are composite materials with high strength to weight ratios that can be used in the present invention. 
   For purposes of the present invention, the opening  16  provides access to the cargo hold  17  for placing luggage and cargo into the container  15 . The opening  16 , which is preferably located in the front panel  26 , is defined by an edge  30 . A flange  32  surrounds the opening  16  and extends into the cargo hold  17  from the edge  30  of the opening  16 . The flange  32  is substantially perpendicular to the front panel  26  and is formed to be continuous with the container  15  in a unitary construction. For purposes of the present invention, bolt holes  34  are formed through the flange  32  in a direction substantially parallel to the front panel  26  of the container  15 . The bolt holes  34  are formed to accommodate corresponding bolts  36  that may be included in the containment device  14 . Additionally, bolt brackets  38  are mounted to an exterior surface  40  of the front panel  26  near the bolt holes  34 . Each bolt bracket  38  includes a bolt hole  39  ( FIG. 4 ) constructed to accommodate the corresponding bolt  36 . 
   As shown in  FIG. 1 , the containment device  14  also includes a door  41 , which is used to cover the opening  16 . Referring now to  FIG. 2 , the door  41  includes a door panel  42 . A front side  44  of the door panel  42  has a substantially planer surface that is circumscribed by edges  46  forming a border  47 . The edges  46  are substantially perpendicular to the front side  44  of the door panel  42 . Preferably, the door panel  42  is constructed of a high strength to weight material that is the same composite material used to construct the container  15 . Additionally, the door  41  includes one or more door handles  48  that are mounted on the front side  44  of the door panel  42 . Although the containment device  14  is shown and described as having only one opening  16  and one door  41 , it will be appreciated that the container  15  may have additional doors  41  and corresponding openings  16 . Moreover, the opening  16  and the door  41  may have geometric shapes other than a square or rectangular shape, and the opening  16  may be formed on a panel other than the front panel  26 . 
   As shown in  FIG. 2 , the generally designated door  41  includes a bite  50  that is formed along the edges  46  of the door panel  42  and extends in a perpendicular direction away from the front side  44  of the door panel  42 . The bite  50  includes a top section  52  that is substantially parallel to a bottom section  54 , and a left section  56  that is substantially parallel to a right section  58 . As shown in  FIG. 3 , the bite  50  has a core  60 , which may be hollow or solid. Furthermore, the bite  50  has a number of bolt holes  62  formed through the left section  56  and the right section  58  of the bite  50  in a direction substantially parallel to the front side  44  of the door panel  42  and substantially perpendicular to the edges  46  of the door panel  42 . The bolt holes  62  in the bite  50  are substantially the same size as the bolt holes  34  in the flange  32  and are formed to accommodate the corresponding bolts  36  ( FIG. 1 ). Preferably, the bite  50  is constructed of a high strength to weight material that is the same material used to construct the container  15  ( FIG. 1 ) and the door panel  42 . Referring to  FIG. 2 , the door  41  may include one or more side handles  64  mounted to the door  41 . Preferably, one side handle  64  is mounted to the right section  58  of the door  41  as shown in  FIG. 2 . 
   More details of the door  41  are shown in  FIG. 4 . When the door  41  is covering the opening  16 , the flange  32  is juxtaposed with the bite  50  and the door panel  42  is substantially perpendicular to an end  68  of the flange  32 . Preferably, the door panel  42  is slightly separated from the end  68  of the flange  32  as shown in  FIG. 4 . Moreover, the flange  32  and an interior surface  65  of front panel  26  form an L-shaped seat  70 . Preferably, the seat  70  is formed with additional layers of composite material to strengthen the container  15  around the opening  16 . As shown in  FIG. 4 , seat  70  is shaped to contact the bite  50  when the door  41  is covering the opening  16 . 
   As shown in  FIG. 4 , an optional seal  66  may be affixed to the interior surface  65  of front panel  26  at the seat  70 . When the door  41  is covering the opening  16  and the bite  50  is juxtaposed with the flange  32 , the seal  66  is between the bite  50  and the front panel  26  of the container  15 , and the bite  50  is pressed against the seal  66 . Preferably, the seal  66  is made from a readily available commercial elastomeric material that can maintain effectiveness at high pressure over a range of temperature conditions. For example, the seal  66  may be made of rubber, neoprene, or polyurethane. Furthermore, the seal  66  may be a commercially available gasket, engine seal, O-ring or submersible seal. Preferably, the seal  66  is a long continuous strip that is form fitted and affixed to the front panel  26  at the seat  70 , and which mates smoothly with the bite  50  when the door  41  is covering the opening  16 . 
   When the door  41  is covering the opening  16 , one end of the bolt  36 , which preferably has a U-shape construction, is positioned into the bolt hole  34  of the flange  32  and into the bolt hole  62  of the bite  50 . As shown in  FIG. 4 , the bolt hole  34  is substantially coaxial with the bolt hole  62  when the bolt  36  is positioned into the bolt holes  34  and  62 . Additionally, the other end of the bolt  36  is positioned into the bolt hole  39  in the bolt bracket  38 . As shown in  FIG. 4 , the bolt hole  39  in the bolt bracket  38  is substantially parallel to the bolt hole  34  in the flange  32  and the bolt hole  62  in the bite  50 . When positioned into the bolt holes  34 ,  39  and  62 , the bolt  36  conforms to a portion of the front panel  26  of the container  15  and the flange  32  to hold the door  41  over the opening  16 . It will be appreciated that the bolts  36 , the bolt brackets  38 , and bolt holes  34 ,  39  and  62  are optional in the containment device  14 , and that other mechanisms known in the art may be used to hold the door  41  over the opening  16 . 
   Alternatively, the seal  66  may be absent from the front panel  26  of the container  15 . In this situation, the bite  50  is pressed against the seat  70  and the door panel  42  is pressed against the end  68  of the flange  32  when the door  41  is covering the opening  16  and the bolts  36  are positioned in the bolt holes  34 ,  39  and  62 . Preferably, a gap  72  exists between the bite  50  and the seat  70  and another gap  74  exists between the door panel  42  and the end  68  of the flange  32  when the bite  50  is pressed against the seat  70 . Referring to  FIG. 4 , it can be seen that the gap  72  exists between the bite  50  and the front panel  26  of the container  15  when the seal  66  is absent from the front panel  26 . 
   More details of the door  41  are shown in  FIGS. 5 and 6 . The left panel  22  of the container  15  has an interior surface  76  and the right panel  24  of the container  15  has an interior surface  78 . Additionally, the bottom panel  20  has an interior surface  80 . As shown in  FIG. 7 , the top panel  18  has an interior surface  82  and the back panel  28  has an interior surface  83 . Referring to  FIGS. 5 and 6 , the container  15  includes a left bracket  84  and a right bracket  86 . Preferably, the left bracket  84  and the right bracket  86  are planar surfaces that are substantially parallel to each other and to the left panel  22  and the right panel  24  of the container  15 . The left bracket  84  and the right bracket  86  may be mounted to one or more panels  18 ,  20 ,  22 ,  24 ,  26  or  28  of the container  15 . Additionally, the left panel  22  or the right panel  24  may form the left bracket  84  or right bracket  86 , respectively. For example, the right panel  24  forms right bracket  86  as shown in  FIGS. 5 and 6 . 
   Referring to  FIG. 7 , the container  15  also includes a bottom bracket  88  and a top bracket  90 . Preferably, the bottom bracket  88  and the top bracket  90  are planar surfaces that are substantially parallel to each other and to the top panel  18  and the bottom panel  20  of the container  15 . The bottom bracket  88  and the top bracket  90  may be mounted to one or more panels  18 ,  20 ,  22 ,  24 ,  26  or  28  of the container  15 . Preferably, the top panel  18  and the bottom panel  20  form the top bracket  90  and the bottom bracket  88  respectively, as shown in  FIG. 7 . 
   A containment device  14  in which the door  41  interacts with the container  15  in a substantially lateral direction is shown in  FIGS. 5 ,  6  and  7 . As seen in  FIGS. 5 and 6 , a bottom cradle  92  is mounted to the bottom panel  20 . More details of the bottom cradle  92  are shown in  FIG. 8 . The bottom cradle  92  includes a plate  94  for supporting the door  41  ( FIG. 7 ). The plate  94  has a substantially planer top surface  96  that is circumscribed by a border  98 . The bottom cradle  92  also includes a frame  100  mounted to the top surface  96  of the plate  94  along the border  98 . The frame  100  extends away from a top surface  96  of the plate  94  in a direction substantially perpendicular to the top surface  96 . Preferably, the frame  100  is formed along only a portion of the border  98  as shown in  FIG. 8 . The bottom cradle  92  may engage the left bracket  84 , the right bracket  86 , and the interior surface  65  of front panel  26  ( FIG. 6 ). Additionally, the bottom cradle  92  may be mounted to the left bracket  84 , the right bracket  86 , or the interior surface  65  of front panel  26 . 
   As shown in  FIG. 7 , a top cradle  102  is mounted to the top panel  18 . More details of the top cradle  102  are shown in  FIG. 9 . The top cradle  102  has a frame  104  that preferably has the same dimensions and structure as the frame  100  of the bottom cradle  92  ( FIG. 8 ). The top cradle  102  may engage the left bracket  84 , the right bracket  86 , and the interior surface  65  of front panel  26  ( FIG. 6 ). Additionally, the top cradle  102  may be mounted to the left bracket  84 , the right bracket  86 , or the interior surface  65  of front panel  26 . 
   A containment device  14  in which the door  41  interacts with the container  15  in a substantially upright direction is shown in  FIGS. 10 ,  11  and  12 . As shown in  FIG. 10 , the door  41  has an outside surface  105  on the left section  56  of the bite  50  along the border  47  of the door panel  42 . Additionally, the door  41  has an outside surface  106  on the right section  58  of the bite  50  along the border  47  of the door panel  42 . Rollers  108  are mounted to the outside surface  105  of the left section  56  and to the outside surface  106  of the right section  58  with axles  109 . Preferably, the door  41  includes four door handles  48  mounted to the front side  44  of the door panel  42 . The door  41  may also include one or more side handles  64 , preferably mounted to the bottom section  54  of the bite  50 . 
   As shown in  FIG. 11 , guide rails  110   a  and  110   b  are respectively mounted to the left bracket  84  and right bracket  86  in the container  15 . Preferably, the right bracket  86  is the right panel  24  of the container  15 , and the guide rail  110   b  is mounted directly to the right panel  24 . Additionally, the left bracket  84  may be the left panel  22  of the container  15 , in which case the guide rail  110   a  is mounted directly to the left panel  22 . As shown in  FIG. 11 , the guide rails  110   a  and  110   b  are offset from the interior surface  65  of the front panel  26  to accommodate the rollers  108  that are positioned between the front panel  26  and the guide rails  110   a  and  110   b.    
   Referring to  FIG. 12 , the guide rails  110   a  ( FIG. 11) and 110   b  have an upper opening  112  and a lower opening  114  that are slightly larger than a diameter of the rollers  108 . Furthermore, the guide rails  110   a  and  110   b  have a T-shaped or L-shaped slot  116  that is dimensioned to accommodate the rollers  108  and the axles  109 . The upper opening  112  and the lower opening  114  provide access to the slot  116  for the rollers  108 . Preferably, the slot  116  closely conforms to the shape of the rollers  108  and the axels  109 . For example, the slot  116  may have a wider portion to surround the rollers  108  and a narrow portion to surround the axles  109 , as shown in  FIG. 11 . 
   The guide rails  110   a  and  110   b  can be described in greater detail with reference to  FIGS. 11 and 12 . As shown in  FIG. 12 , the guide rail  110   b  is mounted to the right panel  24  of the container  15 . It will be appreciated that the structure of the guide rail  110   a  may differ from the structure of the guide rail  110   b , but that the guide rail  110   a  can be described referring to the guide rail  110   b  shown in  FIG. 12  and  FIG. 11 . Preferably, the guide rails  110   a  and  110   b  engage the interior surface  82  of the top panel  18 , the interior surface  83  of the back panel  28 , and the interior surface  80  of the bottom panel  20 . The guide rails  110   a  and  110   b  extend from the bottom panel  20  to the top panel  18  in a direction substantially parallel to the interior surface  65  of the front panel  26 . At the top panel  18 , the guide rails  110   a  and  110   b  curve and extend toward the back panel  28  in a direction substantially parallel to the interior surface  82  of top panel  18 . 
   For the operation of the containment device  14 , the door  41  is retracted into the cargo hold  17  to uncover the opening  16 , as shown in  FIG. 6 . While the door  41  is being retracted into the cargo hold  17 , the bolts  36  are absent from the bolt holes  62  in the bite  50  of the door  41 . Preferably, the bolts  36  are also absent from the bolt holes  34  of the flange  32  and the bolt holes  39  of the bolt bracket  38  ( FIG. 4 ). The door  41  may be retracted into the cargo hold  17  in either a substantially lateral direction or a substantially upright direction. 
   Operation of a containment device  14  in which the door  41  interacts with the container  15  in a substantially lateral direction is best described with reference to  FIGS. 4 ,  5 ,  6  and  7 . As shown in  FIGS. 4 and 5 , the door  41  is covering the opening  16 , and the bolts  36  are positioned in the respective bolt holes  34 ,  39  and  62  of the flange  32 , the bolt bracket  38  and the bite  50  of the door  41 . Before opening the door  41  to uncover the opening  16 , an operator removes the bolts  36  from the bolt holes  34 ,  39  and  62 . The operator then pushes the door  41  toward the back panel  28  of the container  15  until the top cradle  102  and the frame  100  of the bottom cradle  92  restrict further movement of the door  41 . Preferably, the operator pushes on the door handles  48  to move the door  41  toward the back panel  28 . As the operator pushes on the door handles  48 , the door  41  retracts into the cargo container  15  in a substantially lateral direction. 
   The operator then pushes the door  41  in a substantially lateral direction toward the left panel  22  until the top cradle  102  and the frame  100  of the bottom cradle  92  that are near the left bracket  84  restrict further movement of the door  41 , as shown in  FIG. 6 . Preferably, the operator uses the door handles  48  and the side handles  64  to push the door  41  toward the left panel  22 . As the operator pushes on the door handles  48  and the side handle  64 , the door  41  retracts further into the cargo hold  17 . With the door  41  opened, the operator has access to the container  15  through the opening  16  to place items into, and remove items from, the cargo hold  17 . 
   To close the door  41 , the operator pulls on the door handle  48  or the optional side handle  64  to move the door  41  in a substantially lateral direction toward the right panel  24  of the container  15  until portions of the top cradle  102  and the frame  100  of the bottom cradle  92  that are near the right bracket  86  restrict further movement of the door  41 . The operator then pulls on the door handle  48  to move the door  41  in a substantially lateral direction toward the front panel  26  of the container  15  until the bite  50  of the door  41  presses against the seal  66 , as shown in  FIG. 5 . If the seal  66  is not present, the bite  50  instead presses against the seat  70 . In either case, the bolt holes  34  in the flange  32  are lined up to be coaxial with the holes  39  in the bite  50 , and the door panel  42  covers the opening  16 . The operator then places the bolts  36  into the respective bolt holes  34 ,  39  and  62  of the flange  32 , bolt bracket  38  and bite  50  of the door  41 . 
   Operation of a containment device  14  in which the door  41  interacts with the container  15  in a substantially upright direction is best described with reference to  FIGS. 4 ,  11  and  12 . As shown in  FIGS. 4 and 11 , the door  41  is covering the opening  16 , and the bolts  36  are positioned in the respective bolt holes  34 ,  39  and  62  of the flange  32 , bolt bracket  38  and bite  50  of the door  41 . Before opening the door  41  to uncover the opening  16 , an operator removes the bolts  36  from the bolt holes  34 ,  39  and  62 . The operator then pushes the door  41  in a substantially lateral direction toward the back panel  28  of the container  15  until the rollers  108  pass through the upper and lower openings  112  and  114  of the guide rails  110   a  and  110   b  and are aligned with the slot  116 . 
   The operator then pushes the door  41  in a substantially upright direction toward the top panel  18  ( FIG. 12 ) of the container  15 . As the door  41  moves toward the top panel  18 , the slots  116  in the guide rails  110   a  and  110   b  guide the rollers  108  along the guide rails  110   a  and  110   b . The guide rails  110   a  and  110   b  direct the rollers  108  toward the top panel  18 , and then toward the back panel  28  until the door  41  contacts the back panel  28  of the container  15 . When the door  41  contacts the back panel  28 , the door  41  is substantially parallel to the interior surface  82  of the top panel  18  of the container  15 . With the door  41  opened, the operator has access to the container  15  through the opening  16  to place items into, and remove items from, the cargo hold  17 . 
   To close the door  41 , the operator pulls on the door handles  48  or the optional side handle  64  in a substantially downward direction to move the door  41  toward the bottom panel  20  of the container  15  until the door  41  contacts the bottom panel  20 . The operator then pulls on the door handles  48  to move the door  41  in a substantially lateral direction toward the front panel  26  of the container  15  until the bite  50  of the door  41  presses against the seal  66 . If the seal  66  is absent, the bite  50  instead presses against the flange  32  or seat  70 . In either case, the door panel  42  covers the opening  16 , and the bolt holes  34  in the flange  32  are lined up to be coaxial with the holes  39  in the bite  50 . The operator then places the bolts  36  into the respective bolt holes  34 ,  39  and  62  of the flange  32 , bolt bracket  38  and bite  50  of the door  41 . 
   Should an explosive detonation occur in the cargo hold  17 , a resultant explosive force on the door panel  42  will be transferred to the bite  50  and cause the bite  50  to press against the seal  66  to form an airtight seal between the bite  50  and the container  15 . It is important for the present invention that the bolts  36  not prevent the bite  50  from pressing against the seal  66  when the seal  66  is present. For example, the bolts  36  may be constructed to shear when an explosive force on the door panel  42  is transferred to the bite  50  and which forces the bite  50  against the seal  66  or the seat  70 . It is also possible to form the bolt holes  62  of the bite  50  to have a larger size than is necessary to accommodate the bolts  36 . In this situation, the bolts  36  will not shear but will move relative to the bolt holes  62  when the bite  50  is forced against the seal  66  or the seat  70 . 
   When the bite  50  is pressed into the seal  66 , the seal  66  prevents gasses from flowing into, or flowing out of, the cargo hold  17 . For example, the seal  66  will prevent leakage of hazardous or toxic materials from the cargo hold  17 , and will also prevent ambient air from entering the container  15 , which may promote deflagration in the cargo hold  17 . Additionally, the seal  66  transfers the explosive force from the bite  50  to the front panel  26  of the container  15  and uniformly distributes the explosive force to the container  15  at the seat  70 . If the optional seal  66  is absent from the seat  70 , the bite  50  instead transfers the explosive force from the door panel  42  to the container  15  and uniformly distributes the explosive force to the container  15  at the seat  70 . 
   Whether or not the seal  66  is present, the bite  50  prevents the door  41  from warping as a result of the explosive blast while uniformly distributing the explosive force to the container  15 . Furthermore, the bite  50  bonds tightly to the seat  70  in response to an explosive force in the cargo hold  17  to balance the in-plane tension stresses in all directions on the door panel  42 . Because the container  15  is formed of a unitary construction, a concentration of tension stresses from the explosive force are reduced in the container  15 . Accordingly, the door panel  42  and the container  15  will resist rupturing when subjected to tension stresses caused by the explosive blast. 
   While the particular blast resistant containment device and method as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.