Abstract:
A container system and method for shipping and storing an item is provided. The container system may comprise a storage vessel with an interior compartment, and an access opening at one end. A removable end cap may be releasably and mechanically coupled to the storage vessel at the access opening, fully enclosing the access opening. Mechanical fasteners may also be secured to the storage vessel and removable end cap to form the releasable, mechanical connection. In one embodiment, at least one stacking lug may be provided at the perimeter of the storage vessel. In another embodiment, the container may comprise a pressure vessel, which may be adapted to receive a round of ammunition.

Description:
RELATED APPLICATION 
   This application is a continuation of U.S. application Ser. No. 09/224,218 filed Dec. 30, 1998 entitled Ammunition Shipping and Storage Container and Method, now U.S. Pat. No. 6,290,087. 

   TECHNICAL FIELD OF THE INVENTION 
   The present invention relates to shipping and storage containers and systems, and in particular, to a system and method for storing and transporting ammunition. 
   BACKGROUND OF THE INVENTION 
   A round of ammunition may include a missile and an associated missile launch tube assembly. In order to protect the round as far forward in a military theater as possible, it is preferable to keep the round in the container as long as possible. Protection is also required for shipping and storage of the round. 
   Current shipping containers used for missiles and ammunition are typically constructed from aluminum or steel. Aluminum containers are prone to impact damage and puncture, are difficult to seal, require costly maintenance when damaged, and require painting for marking and corrosion resistance in a chemical agent environment or where camouflage is required. Steel containers are a very heavy alternative and do not solve these problems. Also, steel and aluminum containers are expensive since each requires large lengths of welding and gasket-compatible tolerances. 
   During shipment and storage of the containers, multiple containers are stacked upon one another. It is desirable to secure these containers firmly in place, against one another. Frequently, the weight of the containers causes damage to containers below, requiring repair and/or disposal of damaged containers. 
   Due to elevation changes inherent in transporting rounds of ammunition, the container may incorporate an automatic pressure relief or “breather” valve to prevent pressure differential between the container and ambient atmosphere. At higher elevations, the breather valve vents air pressure from within the container to account for the associated ambient pressure drop. During descent, air is forced through the breather valve into the container to accommodate increased ambient pressure. As air enters the interior of the container, its contents may be exposed to moisture and other pollutants associated therewith. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a shipping and storage container which can withstand the pressure differential associated with changes in elevation without the use of a breather valve, and, in particular, to provide a container which employs a pressure vessel as the storage media. 
   Another object is to provide a light-weight shipping and storage container to decrease the burden of vehicular and manual transportation thereof. 
   Yet another object of the present invention is to reduce the labor and material costs associated with the manufacture of shipping and storage containers. 
   Still another object is to provide a durable stackable container which can be mobilized and deployed with enhanced efficiency. 
   The foregoing objects are attained in accordance with the present invention by employing a high strength, “pipe-grade” storage vessel capable of withstanding significant pressure differentials with minimal deformation, as the storage component. In a particular, embodiment, a removable end cap provides access to the interior of the storage vessel. A pair of backing rings may be provided to axially support plastic flanges which form the interface between the end cap and the storage vessel. 
   In another embodiment, a rubber gasket may be provided to form a generally air-tight seal between the end cap and the storage vessel. In one particular embodiment, one or more stacking lugs may be disposed upon the exterior of the pressure vessel to provide a secure, releasable stacking connection to adjacent storage containers. A number of ergonomic handling features may also be incorporated into the stacking lugs. 
   In another embodiment, a lever clamp assembly may provide a releasable, mechanical connection between the removable end cap and the storage vessel. The assembly may incorporate a lever clamp “U-bolt” and pivot clamp facilitating the secured coupling and rapid removal of the end cap assembly. 
   In yet another embodiment, a humidity indicator may be incorporated into the pressure vessel to allow for early detection of a breach in the integrity of the air-tight seal. A manual pressure relief valve may also be provided to breach the air tight seal prior to missile deployment. This allows the operator to remove the end cap without having to overcome the force associated with a pressure differential between the interior of the pressure vessel and ambient environment. 
   A technical advantage of the present invention includes the ability to withstand pressure differentials without allowing moisture and pollutants to enter the pressure vessel. By limiting the deformation of the container, maintenance and repair due to associated damage is also significantly reduced. 
   Another technical advantage includes the durable, light weight stackable container which facilitates rapid deployment and ease of transportation. Still other technical advantages of the present invention include providing a weld-sealed, impact-resistant, paint-free, minimum-maintenance alternative using plastic materials and manufacturing techniques. 
   Other technical advantages will be readily apparent to one skilled in the art from the following figures, detailed description and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and for further features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a container system embodying aspects of the present invention; 
       FIG. 2  is a partial perspective view, with portions broken away, of a storage vessel; 
       FIG. 3  is a partial perspective view, with portions broken away, of a removable end cap; 
       FIG. 4  is a partial perspective view, with portions broken away, of an aluminum backing ring; 
       FIG. 5A  is a top elevation view, with portions broken away, of a lever clamp assembly; 
       FIG. 5  is a side elevation view, with portions broken away, of a lever clamp assembly; 
       FIG. 6  is a partial elevation, with portions broken away, illustrating a stacking lug; 
       FIG. 7  is a side elevation view, with portions broken away, illustrating a stacking lug; 
       FIG. 8  is a side elevation view, with portions broken away, illustrating a stacking lug; 
       FIG. 9  is a perspective view, with portions broken away, of a weapon system incorporating aspects of the present invention; and 
       FIG. 10  is an end elevation view of three containers stacked upon one another, within the teachings of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a container system comprising a stackable shipping and storage container  30  for rounds of ammunition is provided. Although the illustrated embodiment is suitable to accommodate the United States Army&#39;s Javelin® missile, the teachings of the present invention are adaptable to a variety of other shape factors and applications. Examples include shipping containers for other ammunition rounds as well as overpack secondary containment for leaking chemical or biological weapons. The applications listed herein are not intended to be exhaustive, as the disclosed container may be used to ship, store, transport or protect virtually any article of manufacture. 
   As illustrated in  FIG. 1 , container  30  includes a generally cylindrical, elongate storage vessel  31  with a removable end cap  36  disposed thereupon. A pair of stacking lugs  100  discussed below in greater detail, provide a high-strength stacking surface for ease in shipping, storage and handling of container  30 . 
   Referring now to  FIGS. 1–3 , storage vessel  31  includes a cylindrical hollow tube  32 , fixed end cap  35  and flange assembly  38 . Tube  32  partially encloses an interior compartment  37 . Tube  32  is open at both ends  33  and  34  is thermally welded to fixed end cap  35  at open end  33 . The weld provides a high strength air tight seal between end cap  35  and tube  32 . Flange assembly  38  is thermally welded to tube  32 , in a similar fashion, at open end  34 . In one embodiment, access opening or open end  34  provides access to interior compartment  37 . 
   Storage vessel  31  may be provided with a viewing window  21  to allow viewing of the contents of the storage vessel. For example, if a round of ammunition is contained within vessel  31 , a user may wish to view guages associated with the round. Viewing window  21  is preferably formed from a transparent material of sufficient strength to withstand anticipated pressure differentials between the interior and exterior of storage vessel  31 . Plexiglass ™, for example, may be used. However, the invention is not so limited and other alternatives may be used. The viewing window may be located anywhere on storage vessel  31 . For example, viewing under 21 may be strategically located adjacent a particular part of an item enclosed within storage vessel  31 . 
   Flange assembly  38  includes a first cylindrical neck  40  with a diameter approximately equal to the diameter of hollow tube  32 . A second, larger diameter cylindrical neck  42  is provided to interface with removable end cap  36 . The diameter of second cylindrical neck  42  is less than the diameter of removable end cap  36 . A first circular flange  44  provides a surface upon which a second circular flange  52 , associated with removable end cap  36 , can join to form an air tight seal therebetween. A gasket (not expressly shown) or other sealing material may be provided at the interface between circular flange  44  and circular flange  52  to enhance the generally air tight seal. 
   In the illustrated embodiment, removable end cap  36  and storage vessel  31  are primarily composed of extruded, high-density polyethylene 3408, in accordance with ASTM D3350, with a cell classification PE345444C. This material is a “pipe-grade” quality that meets or exceeds the stringent requirements for pressurized applications within an acceptable range of deformation. Accordingly, this facilitates the removal of the previously required automatic breather valve common to prior containers. Furthermore, this material is suitable to withstand significant pressure differentials between interior compartment  37  and ambient environment without significant temporary or permanent deformation. The strength of the material makes it impact and puncture resistant. “Pipe-grade” polyethylene is lightweight, inexpensive, easy to seal with other components of similar or dissimilar material, and does not require painting for marking or corrosion resistance. It will be recognized by those skilled in the art that other high strength materials can be utilized for the fabrication of these components, within the teachings of the present invention. These include but are not limited to, various plastics, metals, and composite materials. 
   In order to enhance the strength of the connection between flange assembly  38  and removable end cap  36 , an aluminum backing ring  46 , as shown in  FIG. 4 , is provided on the exterior face  48  of circular flange  44 . Aluminum backing ring  46  reinforces the strength of flange  44 . Another aluminum backing ring  54  is provided on the exterior face  56  of circular flange  52 . Aluminum backing ring  54  provides reinforcing strength to circular flange  52 . A plurality of notched protrusions  58  are provided upon end cap  36  which allow aluminum backing ring  54  to be “snapped” on, and held in place during assembly. Many other materials, including but not limited to metals and composites are suitable for fabricating reinforcement backing rings which may be interchanged with aluminum backing ring  46 . 
   In order to enclose and seal container  30  during storage and/or transportation of rounds of ammunition, removable end cap  36  is placed over cylindrical neck  42  of flange assembly  38 . Removable end cap  36  slides over cylindrical neck  42  until circular flange  52  of removable end cap  36  contacts circular flange  44  associated with storage vessel  31 . 
   Four lever clamp assemblies  60  to be described in more detail later, are attached to removable end cap  36  to form a releasable, mechanical connection between flange assembly  38  and removable end cap  36 . One aspect of the present invention includes the ability to protect contents of the container from ambient environmental conditions. This is beneficial due to technological advances and the increased sensitivity of ammunition rounds. Once container  30  is closed and sealed, potential leak paths are minimized. Therefore, the probability of the round inside remaining dry is high, regardless of ambient environmental conditions. This is particularly beneficial for any contents of container  30  which suffer from deterioration upon exposure to moisture. 
   The main seal between removable end cap  36  and flange assembly  38  is unique due to the reinforcement strength provided by aluminum backing rings  46  and  54 . While most prior seals are either a pure facial or radial configuration, both of which require very precise fabrication tolerances, this concept is essentially a compromise between facial and radial designs. The seal will not be exposed to shear loads that often negatively impact a facial seal because of the unique way removable end cap  36  interfaces with flange assembly  38 . In the illustrated embodiment, clamp assemblies  60  compress circular flange  44  firmly against circular flange  52 , thereby distributing the clamp load evenly around the circumference of circular flanges  44  and  52 , and maintaining uniform compression around the circumference of the gasket. Aluminum backing rings  46  and  54  provide reinforcement to circular flanges  44  and  52  respectively, preventing the deformation of circular flanges  44  and  52  in a direction parallel to the longitudinal axis X of tube  32 . Deformation of circular flanges  44  and  52  will only occur along a plane perpendicular to the longitudinal axis X of tube  32 , minimizing any effect on the integrity of the air tight seal therebetween. 
   As illustrated in  FIGS. 5A and 5 , lever clamp assembly  60  includes U-bolt clamp  62 , pivotally and rotationally connected to lever clamp  64 , by means of a pivot clamp  66 . The front bar  68  of U-bolt  62 , grasps a metallic tooth  70  associated with aluminum backing ring  46  (see  FIG. 4 ), forming a releasable connection between U-bolt  62  and aluminum backing ring  46 . A hemispherical protrusion  72  incorporated into lever clamp  64 , secures aluminum backing ring  54  associated with removable end cap  36 , forcing compression between circular flanges  44  and  52 . Other mechanical clamps and connection devices are available to accomplish this releasable connection within the teachings of the present invention. 
   In order to access the contents of container  30 , the operator forces lever clamp  64  away from removable end cap  60  by applying pressure perpendicular to and away from longitudinal axis X of tube  32 . Sufficient pressure will break the connection between hemispherical protrusion  72  and aluminum backing ring  54 . 
   Referring now to  FIGS. 1 and 3 , a manual relief valve  80  is provided to allow the operator to overcome any pressure differential which may exist between the interior of container  30  and ambient atmospheric pressure, prior to removing end cap  36 . By equalizing the pressure, the operator will not have to overcome the force associated with such pressure differentials. 
   Further, humidity indicator  82  may be provided upon removable end cap  36 . This allows the operator or soldier to immediately determine whether the air tight seal of removable end cap  36  has been breached and moisture has entered container  30 . Since moisture may have a detrimental effect on the contents or rounds of ammunition, the operator may want to avoid utilizing exposed munitions. In the illustrated embodiment, humidity indicator  82  is provided upon removable end cap  36 . In practice, humidity indicator  82  may be placed anywhere upon container  30  provided a fluid communication path between humidity indicator  82  and the interior of container  30  is established. 
   In one embodiment, container  30  may constitute a pressure vessel. A pressure vessel is a chamber capable of withstanding “bursting pressures,” which experience relatively little deformation under pressure. However, it is not necessary, in all cases, that vessel  31  constitutes a pressure vessel. 
   Many of the ergonomic features, including stackability, are accomplished by employing one or more stacking lugs  100  as illustrated in  FIGS. 6–8 . Stacking lugs  100  are comprised primarily of rotationally-molded, cross-linked, high density polyethylene. Other high strength material alternatives may be utilized within the teachings of the present inventions. This material is designed to handle transportation and storage loads independent of storage vessel  31  and to distribute the loads around and away from storage vessel  31 . UV stabilized, cross-linked high density polyethylene exhibits high resistant to “creep” under heavy loading. This allows the user to stack multiple loaded containers without significant deformation over time. 
   Stacking lugs  100  include a rectangular housing  102  with a cylindrical opening  104  therethrough. Stacking lugs  100  are “press-fit” onto storage vessel  31  during fabrication of container  30 . The “press-fit” connection is facilitated by providing cylindrical openings  104  of slightly smaller diameter than the diameter of tube  32 . This type of connection is commonly known in the art as “press-fit” or friction fit. Although the illustrated embodiment encompasses the use of two stacking lugs disposed upon storage vessel  31  near the outermost ends, it will be recognized by those skilled in the art that the number and configuration of stacking lugs may be significantly modified within the teachings of the present inventions. 
   Stacking lugs  100  include rectangular protrusions  106  at the top face  108  of mounting lug  100  which conform to rectangular cavities  107  located at the bottom face  110  of mounting lug  100 . Additional containers  230 ,  330  (see  FIG. 10 ) may then be stacked upon container  30  and held in place by the friction fit of rectangular protrusion  106  and the rectangular cavity associated with the other container. When additional containers  230 ,  330  are placed on top of container  30 , top face  108  is in contact with the bottom face of the container above. This allows most of the force from the weight of the containers above to be transferred through stacking lugs  300 ,  200  to top face  108  of stacking lugs  100  and very little force is transferred to storage vessel  31 . This prevents deformation of storage vessel  31  under the weight of the containers above. During shipment and storage, containers will be securely held in place, yet containers may be separated quickly and efficiently during mobilization. 
   Quarter cylindrical cut-outs  112  occur at each corner of top face  108  of stacking lug  100 , with hand-holes  114  formed therein. Handles  116 , installed across the central axis of cut-outs  112 , provide a lifting mechanism suitable to lift and carry container  30 . A second pair of hand-holes  118  are provided within the side faces  120  of stacking lug  100 , nearest the bottom face  110 . Hand-holes  118  provide a convenient mechanism to lift and stack containers  30  high above ground level (e.g., loading onto a flat bed truck). Shipping and storage vehicles and structures, including additional containers, may also be adapted to accommodate rectangular protrusion  106  and rectangular cavity  107  to firmly secure container  30  in place during storage and transportation. The number, shape, size and configuration of protrusions and cavities can be significantly modified within the teachings of the present invention. The dual, parallel configuration of rectangular protrusions  106  form a convenient groove  109  which accommodates shipping straps (not expressly shown). Shipping straps may be installed over container  30 , through groove  109 , and secured to standard shipping pallets for secure packaging and shipment of multiple containers. 
   In order to reinforce the strength of stacking lug  100  a plurality of ties  122  are punched into the outer surfaces of stacking lug  100 . This provides a strengthening feature by bringing the interior surface of stacking lug  100  together with the exterior surface. When the plastic material on the outside face of stacking lug  100  attaches itself to the plastic material on the inside face of stacking lug  100  a honeycomb type effect reinforces the tensile and compressive strength of stacking lug  100 . This prevents stacking lug  100  from deforming under load or pressure. Ties  100  may be unnecessary for certain applications and their number and location can be varied within the teachings of present invention. 
   A lightning rod  130  may be encapsulated within stacking lug  100  during the fabrication process. Lighting protection is accomplished by providing a conductive path through stacking lugs  100  and around the contents of container  30 . When multiple containers are stacked upon each other a continuous conducting path is formed, beginning at the top face  108  of stacking lug  100 , through the interior of stacking lug  100 , and around cylindrical opening  104 , terminating at the bottom face  110  near rectangular cavity  107 . Regardless of the number of containers  32  within a given stack, a continuous path to ground is provided by lightning rods  130 . 
     FIG. 9  illustrates a weapon system  131 . In an embodiment of the invention, a method for transporting and/or storing an item is provided. The item may include a round of ammunition  132 . The method includes providing a container  134  which may be formed as previously described. The container may comprise one or more stacking lugs which may be formed as previously described. The item may be placed within container  134 . The container may be sealed and the item may be maintained within the container during transportation or storage. 
   Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.