Abstract:
The present invention is a reliable, lightweight, environmentally friendly, highly reusable, highly durable, fully collapsible container for use in transporting solid and liquid materials, including those materials governed by the dangerous goods code of the UN regulations. The container employs a selectively sealed lid, a truss system for preventing bulge at the rim of the container so that the rim remains within the footprint of the lid, and an integrated closure system for securing transported contents.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a collapsible, lightweight, durable shipping container for transporting and storing bulk materials and more specifically to a reusable collapsible container with an integrated closure system for secure containment of materials. 
         [0003]    2. Discussion of Background Information 
         [0004]    Plastic and steel drum-style shipping containers commonly retain bulk materials for transportation. These rigid drum containers often transport hazardous liquid and powder materials over long distances without any loss or seepage. Securely retaining hazardous materials in a transport drum is a highly desirable goal, but standard drums present a number of drawbacks that result in inefficiencies, lost profits, injuries and negative environmental impact. 
         [0005]    First, standard drums are cumbersome to maneuver. Operators managing these drums typically employ specialized handling equipment designed for engaging these heavy drums and evacuating contents. Once emptied, these standard drums, such as the commonplace 55 gallon steel drum, remain heavy and cumbersome to handle and load onto and off of pallets and shipment trucks. An operator manually moving empty drums and loading them onto a flatbed for shipping to a reconditioning center for example, must move one drum at a time onto a pallet and/or into a truck bed. 
         [0006]    Second, standard shipping drums made of steel, plastic, and aluminum, for example, occupy a significant amount of space during transport, even when the drums are empty. A standard 53 foot flatbed trailer truck can transport only 208 of the standard 55 gallon steel drums. This increases the number of trucks required to ship a large number of drums and thereby increases fuel consumption and harmful emissions associated with the carbon footprint of the shipping vessels. 
         [0007]    In addition to causing increased carbon emissions, increased risk of injury during handling and decreased efficiency related to maneuverability, metal containers are expensive to purchase, rent and store. They are fairly large and therefore require a considerable amount of space to maintain on site. That required space could be considerable, depending upon the amount of material that must be stored and/or transported. While the storage volume of metal containers is considerable, the volume of material that is storable within multiple containers is diminished by the fact that the metal containers are generally cylindrical in nature. Cylinders generally cannot be oriented in a space-efficient manner. As such, there is a need in the art for containers that will contain a high volume of material securely and be storable in a low volume storage facility. 
         [0008]    Some shipping container designs address issues with regard to reuse and compaction during empty transport. For example, bag containers take up much less space when not in use. Bag container, however, are of insufficient physical characteristics for transport purposes. That is, they are generally not tough enough to stand up to the rigors of movement by mechanical devices such as forklifts, accidental drops into cargo holds, stacking, etc. Moreover, bag containers are easily deformed by their contents. Bag containers, therefore, are not reliably stackable and fail to enable efficient transport or storing of voluminous materials. Similarly, collapsible boxes typically are only semi-rigid at best, tend to bow outward when filled, and are difficult to lift and stack when filled. Most collapsible boxes for industrial shipping uses are heavy assemblies of several layers of components and typically weigh at least 34 pounds when empty, which weight can cause fatigue and more serious conditions related to repetitive lifting by shipping personnel. Furthermore, these boxes incorporate cumbersome bottom flaps that require folding and securing prior to using the container. This processing step wastes valuable time in the field of operation and accordingly causes monetary losses associated with delay. 
         [0009]    Some collapsible boxes and bags employ truss elements woven through their sidewalls to prevent the containers from bulging when filled. Puncturing the sidewall of a box or bag inherently creates a weak point at which the container could catastrophically fail under load forces. Furthermore, these trusses only prevent bulging at particular points along the height of the container and fail to address bulging at the top rim of the container that could prevent a properly fitted engagement with selectively engaged lid element. Furthermore, such lids require closure elements, such as corner ties or duct tape wrapped around the container and lid, to secure the lid to the container. Using tape to secure a lid to a corrugated box causes rapid degradation of the box during repeated application and removal of tape, which can peel off layers of the box. Furthermore tape can tear easily or loose adhesion under certain temperature and humidity conditions. 
         [0010]    A need therefore exists for a reliable, lightweight, environmentally friendly, highly reusable, highly durable, fully collapsible container for use in transporting solid and liquid materials, including those materials governed by the dangerous goods code of the UN regulations. A need exists for such a container that employs a selectively sealed lid and an integrated closure system for securing transported contents. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention solves the problems associated with efficiently and securely transporting reusable shipping containers designed for retaining bulk materials, including hazardous substances, and insuring reliable structural integrity with every use. The collapsible container has a permanently secured, collapsible wrap tray bottom, an integrated, non-destructive secure closure system, and scored sidewalls that enable an operator to collapse the container flat for compact transport and storage during periods of non-use. 
         [0012]    One embodiment of the collapsible container of the present invention comprises a continuous rigid structure having four planar sides defining four inner surfaces and four outer surfaces. Two opposed planar sides each have a scoring line therein rendering the continuous rigid structure collapsible. The embodiment further comprises a five-walled inelastic wrap tray made of a flexible, inelastic fabric affixed to a lower portion of each the four outer surfaces and defining a bottom surface of the collapsible industrial shipping container. 
         [0013]    In one embodiment the collapsible container comprises at least three side closure strips fixedly disposed on the outer surfaces of three consecutive planar sides, one end of each of the at least three side closure strips securely connecting to the inelastic wrap tray, the other end of each of the at least three side closure strips terminating in an inwardly facing closed retention loop positioned adjacent the top rim of the continuous rigid structure. In one embodiment, each of the at least three side closure strips comprises a closure means fixedly positioned along its length at a point below the top rim of the continuous rigid structure and above the five-walled inelastic wrap tray. 
         [0014]    In one embodiment, the collapsible container further comprises a lid defining at least one hingedly attached flap affixed to the fourth outer surface such that a fourth inwardly facing retention loop is securely affixed between the flap and the fourth outer surface and positioned adjacent the top rim of the continuous rigid structure. In this embodiment, a system of one or more top closure straps affixed to the top surface of the lid are adapted for engaging with the attachment means. 
         [0015]    In one embodiment of the present invention, an inelastic member passes through each of the inwardly facing closed retention loops of the at least three side closure strips and the fourth inwardly facing retention loop, thus preventing the top rim of the continuous rigid structure from bulging under load conditions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    One will better understand these and other features, aspects, and advantages of the present invention following a review of the description, appended claims, and accompanying drawings: 
           [0017]      FIG. 1  depicts a perspective side view of one embodiment of the collapsible container of the present invention having a closed lid. 
           [0018]      FIG. 2  depicts a perspective side view of one embodiment of the container of the present invention having an open lid. 
           [0019]      FIG. 3A  depicts an exploded bottom perspective view of one embodiment of the collapsible container of the present invention. 
           [0020]      FIG. 3B  depicts an exploded side perspective view of one embodiment of the collapsible container of the present invention. 
           [0021]      FIG. 4A  depicts a partial perspective side view of one embodiment the collapsible container of the present invention with the lid closed. 
           [0022]      FIG. 4B  depicts a perspective top view of the collapsible container of  FIG. 4A  with the lid open. 
           [0023]      FIG. 4C  depicts a partial perspective side view of the collapsible container of  FIG. 4A  with the lid open. 
           [0024]      FIG. 5  depicts a bottom view of one embodiment of the collapsible container of the present invention in a collapsed state. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The present invention solves the problems associated with standard drum-style and box-style shipping containers. The present invention provides a collapsible container that is rigid enough for stacking, storing and transporting a variety of materials. Unlike ubiquitous metal containers and standard corrugated box containers, however, the container of the present invention can be collapsed from a substantially cubic volume into a substantially flat square for easy stacking and storage. Additionally, the present invention can be securely closed without requiring the application of destructive tapes or flimsy ties. Furthermore, the present invention addresses preventing bulge at the top rim so that a lid properly engages for securing container contents, and the bulge prevention mechanism is applied without puncturing the container and creating a mode around which the container could catastrophically fail during use. The present invention thus provides numerous benefits to the user, as described more fully below with reference to the drawings. 
         [0026]      FIGS. 1 through 3B  depict one embodiment of the collapsible container  100  in a fully expanded state, positioned on a standard shipping pallet  500 . In this embodiment, the collapsible container comprises a continuous rigid structure  200 , an inelastic wrap tray  300  and an integrated lid  400  for sealing contents within the collapsible container  100  for shipment or storage. The continuous rigid structure  200  may be single walled. In a preferred embodiment, however, the continuous rigid structure  200  is at least double walled and made from a rigid material, such as, for example, fiberboard or corrugated cardboard or any lightweight, rigid material having high compression strength in an axial direction for withstanding the force of one or more filled and stacked collapsible containers  100  without buckling. In one embodiment, the lightweight fiberboard is coated for water resistance. In the depicted embodiment of  FIGS. 3A and 3B , the continuous rigid structure is constructed from a continuous sheet of material formed into a symmetrical, four walled, square tube with open ends. Rigid structures having other symmetrical and asymmetrical tube cross-sectional shapes are contemplated by this invention, such as but not limited to, rectangular, hexagonal, and octagonal cross-sectional shapes. 
         [0027]    The depicted square embodiment of the continuous rigid structure  200  therefore comprises four sides  205 ,  210 ,  215 , and  220 . The four sides  205 ,  210 ,  215 , and  220  are not structurally independent, and thereby provide a fully rigid structure without a plurality of riveted, stapled or adhesively-sealed seams that would decrease structural integrity by providing zones of weakness inviting potential failure and separation of structural components under load and handling forces. Each of the four sides  205 ,  210 ,  215 , and  220  is flat, or substantially planar, and each side has an inner surface parallel to an outer surface. Two opposed sides  210 ,  220  of the four sides  205 ,  210 ,  215 , and  220  each have a scoring line  225  down the middle thereof for rendering the continuous rigid structure  200  collapsible into a flattened, substantially planar structure as further described herein. The scoring lines  225  need not be down the middle of their respective planar surfaces as long as they are parallel to one another, or otherwise properly aligned, for enabling compact collapse of the collapsible container  100  into a planar structure that is easily and compactly stacked, handled and stored. Certain tubular cross-sectional shapes, such as triangular, for example, may require offsetting the scoring lines  225  to achieve a flattened, substantially planar collapsed container. 
         [0028]    The scoring lines  225  allow a user to collapse and store the present invention in the minimum amount of space while maintaining the structural rigidity of the collapsible container  100 . For example, in one embodiment of a thirty-six (36) inch cubic volume collapsible container, a standard fifty-three (53) foot shipping truck transports eight hundred and forty (840) collapsed units as opposed to five hundred and sixty (560) empty units of a comparably sized, standard triple-walled shipping box. The outstanding compacting capabilities of the collapsible container  100 , and the reduced weight per double-walled collapsible container  100 , as compared to standard triple-walled shipping containers, therefore reduces shipping fuel costs because fewer required shipping trucks are required for transporting empty, reusable containers. In the described embodiment of the present invention, a single collapsible container  100  weighs approximately only twenty (20) pounds as opposed to a similarly dimensioned, standard triple walled shipping box weighing thirty-four (34) pounds. This lightweight design facilitates efficient and safe transport and handling, particularly by personnel porting empty collapsible containers  100  onto and off of shipping pallets. 
         [0029]    In all embodiments, successful repeated collapse and compaction and of the present invention relies on proper placement and design of the scoring lines  225 . The scoring lines  225  are not sufficiently deep so as to damage or diminish the structural integrity of the continuous rigid structure  200 . In other words, the scoring lines  225  do not pass all the way through the double-walled thickness of the continuous rigid structure  200 , but merely provide a point of flexure at which to collapse the collapsible container  100  when empty. In fact, the scoring lines need not be cuts at all and may be compression lines running down the length of the inner and/or outer surfaces of at least two opposed planar sides  210 ,  220  of the continuous rigid structure  200 . In one embodiment, the scoring lines  225  are applied on the outer surface of two opposed sides  210 ,  220  of the four sides  205 ,  210 ,  215 , and  220  and in another embodiment the scoring lines are applied to the inner and outer surfaces of two opposed sides  210 ,  220  of the four sides  205 ,  210 ,  215 , and  220  without connecting to form a full cut or full compression. In one embodiment, for example, a cut forming scoring line  225  may penetrate one third of the way or less into the thickness of a side  210 ,  220  and preferably penetrates a quarter of the way or less into the thickness of a side  210 ,  220 . In another embodiment, the scoring lines  225  may be areas of compression where the continuous rigid structure  200  is indented and completely flattened from one or both sides. In a preferred embodiment of the present invention, the scoring lines  225  are linear areas of compression at which the continuous rigid structure  200  is indented from only one side (e.g. the outside surface of two opposing sides  210 ,  220 ) by a platen press, for example. Preferably, the continuous rigid structure  200  is indented and completely flattened by the one-sided pressing process. 
         [0030]    Turning back now to the formation of the collapsible container  100 , the continuous rigid structure  200  requires the addition of a bottom surface for retaining contents. Requiring no fiberboard bottom further assists in reducing the weight of the collapsible container  100  by at least thirty percent (30%) as compared to triple-walled fiberboard containers of comparable size, which typically comprise overlapping bottom flaps that require tedious folding, assembly and securing to form a bottom. Furthermore, as already indicated, the reduction in weight adds to ease of use in the field and a reduction in freighting cost per container. The bottom of the collapsible container  100  is established by assembling the continuous rigid structure  200  with the inelastic wrap tray  300  which has four walls  305 ,  310 ,  315 ,  320  and a flexible, collapsible bottom member  325  extending between and connecting the four walls  305 ,  310 ,  315 ,  320 . The flexible, collapsible bottom member  325  eliminates the need for the continuous rigid structure  200  to comprise a solid, weighty bottom surface requiring time-consuming, inefficient assembly. 
         [0031]    Unlike shipping containers having flaps for folding in place to form a bottom surface, the present invention requires no complex or time consuming assembly to establish a bottom surface. The bottom member  325  of the wrap tray expands automatically during expansion of the collapsed continuous rigid structure  200  and entirely eliminates the hassles associated with bottom flaps, which frequently pop open during use and stick out during use and compaction. Such extraneous members typically incur damage during processing for reuse. For example, processing a typical folding container for reuse often tears away or otherwise dings, cuts or bends the bottom flaps, thereby rending the container structurally deficient and incapable of reuse. 
         [0032]    By design, the inelastic wrap tray  300  of the present invention eliminates the risks and hassles involved in folding, unfolding and handling bottom flap members. Furthermore, the inelastic wrap tray protects the continuous rigid structure  200  from handling damage and environmental wear, thereby extending the life of the collapsible container  100 . The inelastic wrap tray  300  is a five walled tray made from a collapsible, water resistant, tear resistant, inelastic material such as, but not limited to woven polypropylene, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. The four walls  305 ,  310 ,  315 ,  320  of the inelastic wrap tray  300  coincide with the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  220  and are fixedly adhered thereto with adhesive or some other attachment means for securing the inelastic wrap tray  300  to the continuous rigid structure  200 . The inelastic wrap tray  300  may be, for example, shrink wrapped, adhesively affixed, riveted, stapled or press fitted to the outer surfaces of the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  200 . 
         [0033]    In one embodiment, assembly requires placing the continuous rigid structure  200  is placed into the inelastic wrap tray  300  in a compressed state with the continuous rigid structure  200  abutting the inner surface of the bottom member  325  of the wrap tray  300 , and then expanding the continuous rigid structure  200  so that the outer surfaces of the four sides  205 ,  210 ,  215 ,  220  abut the inner surfaces of the walls  305 ,  310 ,  315 ,  320  of the inelastic wrap tray  300 . An adhesive may be applied across one or both of the outer surfaces of the four sides  205 ,  210 ,  215 , and  220  and/or inner surfaces of the walls  305 ,  310 ,  315 ,  320  of the inelastic wrap tray  300  prior to insertion or expansion. In one embodiment, adhesive is applied uniformly across the entire outer surface of each of the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  220 . In another embodiment, adhesive is applied to each outer surface of each of the four sides  205 ,  210 ,  215 ,  220  along the perimeter of the area covered by the walls  305 ,  310 ,  315 ,  320  of the inelastic wrap tray  300 . In yet another embodiment, the outer surfaces of the four sides  205 ,  210 ,  215 ,  220  and inner surfaces of the walls  305 ,  310 ,  315 ,  320  are spot tacked together. In one embodiment, less adhesive or no adhesive may be applied when the inelastic wrap tray  300  is tightly fitted to the continuous rigid structure  200  such that compressive forces and/or frictional forces securely bind the two components to prevent separation or slippage during use. However, in all embodiments, applying adhesive uniformly across all of each outer surface of the four sides  205 ,  210 ,  215 ,  220  and/or inner surfaces of the walls  305 ,  310 ,  315 ,  320  prevents the inelastic wrap tray  300  from warping and wrinkling during use and prevents slippage between the inelastic wrap tray  300  and continuous rigid structure, especially following regular collapse and reuse. 
         [0034]    The inelastic wrap tray  300  therefore is sized and shaped to accommodate the continuous rigid structure therein, while providing a flexible, collapsible bottom member  325  to the collapsible container  100 . Preferably, the lower rim  223  of the continuous rigid structure  200  rests on the flexible, collapsible bottom member  325  of the inelastic wrap tray  300  so that the continuous rigid structure  200  is tightly confined therein and adds compression strength along the entire height of the walls  305 ,  310 ,  315 ,  320  of the inelastic wrap tray  300 . In one embodiment, the walls  305 ,  310 ,  315 ,  320  extend the full height of the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  200 , and in another embodiment depicted in  FIGS. 1 and 2 , the walls  305 ,  310 ,  315   320  extend up to about half the height of the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  220 . This reduces both overall weight and component costs associated with the assembled collapsible container  100 . This configuration also increases ease of assembly in slip fit embodiments of the collapsible container  100  wherein the continuous rigid structure  200  is slipped inside the taught, tightly fitted inelastic wrap tray  300 , with or without adhesive disposed therebetween. 
         [0035]    In one embodiment, the inelastic wrap tray  300  further comprises at least one attachment tab  330  secured at the outer junction of one of one of the walls  305 ,  310 ,  315 ,  320  and the bottom member  325  and enabling handling personnel to securing the collapsible container  100  to a standard shipping pallet by attachment means such as, but not limited to, a nail, staple or non-permanent adhesive. The one or more attachment tabs may be manufactured of the same type of material from which the inelastic wrap tray  300  is manufactured and may be stitched, welded, riveted, stapled or otherwise permanently and securely fastened to the inelastic wrap tray  300 . 
         [0036]    The inelastic wrap tray  300  protects the continuous rigid structure  200  from damage from the elements and damage associated with shipping and handling. Additionally, the inelastic wrap tray  300  assists the continuous rigid structure  200  with resisting radial or expansion forces and preventing bulging during use, shipping and handling. As indicated above, the inelastic wrap tray  300  may be a material such as, but not limited to, woven polypropylene, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. Preferably the material comprising the inelastic wrap tray  300  has a low modulus of elasticity and therefore contributes to the high bulk modulus of the collapsible container  100  of the present invention. The fibers of the inelastic wrap tray  300  preferably exhibit high shear strength so as to withstand radial (i.e. expansion) forces and axial compression forces both under load and under compression while the inelastic wrap tray  300  remains supple enough to avoid fiber degradation and shear strength degradation after repeated use, compaction, and collapse of the collapsible container  100 . 
         [0037]    For example, an inelastic wrap tray  300  extending half the height of the collapsible container  100  and comprising woven polypropylene, assists in counteracting radial expansion forces in a standard UN drop test of a loaded, cubic thirty-six (36) inch double walled fiberboard embodiment of the collapsible container  100 . Subjecting the described embodiment of the collapsible container  100  of the present invention to a standard UN drop test qualifies the collapsible container  100  for a PG 1 rating for transport of solids at 2500 pounds and a PG II/III rating for transport of solids at 2500 pounds, and this embodiment of the collapsible container  100  therefore qualifies for bearing an 11 G UN marking. The fabric of the inelastic wrap tray  300  therefore reinforces the corners  201 ,  202 ,  203 ,  204  of the continuous rigid structure  200  and keeps the collapsible container  100  from splitting open during a standard, required UN drop test for industrial shipping containers. 
         [0038]    In addition to the support provided by the inelastic wrap tray  300 , a lid  400  protects the contents of the collapsible container  100 . In one embodiment, the lid  400  is made of coated, singled walled fiberboard that is both water resistant and lightweight. Preferably, in all embodiments, the lid  400  is formed of a solid, single piece of fiberboard, and therefore enables sealing the collapsible container  100  a single closure step and providing optimum coverage of content retained within the collapsible container  100 . In the embodiments depicted clearly in  FIGS. 1 ,  2  and  5 , the lid  400  comprises at least one hingedly attached flap  405  that is affixed to the outer surface of one of the four sides  205 ,  210 ,  215 ,  220  of the continuous rigid structure  200 . As depicted clearly in  FIGS. 1 and 2 , the hingedly attached flap  405  is secured adjacent the top rim  222  of the continuous rigid structure  200  such that a hinge  407  of the lid  400  aligns with or rests just above the top rim  222 . In one embodiment, the hinge  407  is a score line or area of compressed fiberboard. The hinge  407  may be formed, for example, by compressing and flattening the fiberboard of the lid  400  from one or both sides, thereby enabling flexure along that line or area of compressed material. Formation of such a hinge  407  enables a user to flip the lid  400  forward or backward to cover and uncover the contents within the collapsible container  100  with little effort and only a single movement. 
         [0039]    In one embodiment, depicted in  FIGS. 1 and 2  for example, the hingedly attached flap  405  is adhesively affixed to the outer surface of one planar side  205  of the continuous rigid structure  200 , thereby forming a “hinge side” of the collapsible container  100 . The hingedly attached flap  405  may be secured to the continuous rigid structure  200  in other ways such as, but not limited to, stapling and riveting, or in another embodiment, the lid  400  maybe constructed from the same, single piece of material forming the continuous rigid structure  200  so that the two components are formed as a single, monolithic structure. In one embodiment, best shown in  FIG. 4A , the lid  400  may comprise one or more additional flaps  410 ,  415 ,  420  that are independent of one another, having a gap therebetween at each corner of the lid  400 . Maintaining the hinge side flap  405  and the one or more additional flaps  410 ,  415 ,  420 , as independent members enables flattening the entire assembly upon collapse of the collapsible container  100 . In this embodiment, upon collapse, the lid  400  folds back at the hinge side to rest face-to-face upon the outer surface of the planar side  205  to which it is attached, thereby exposing the bottom surface  430  of the lid  400 . All flaps  405 ,  410 ,  415 ,  420  splay and lie flat, as shown in  FIG. 5 . 
         [0040]    Turing now to securing the lid  400  in a closed position, in one embodiment, the lid  400  is reinforced with a system of one or more top closure straps  435 ,  440  affixed to the top surface  425  of the lid  400 . The one or more top closure straps  435 ,  440  are positioned to engage with one or more side closure strips  250 ,  255 ,  260  disposed on the outer surfaces of the continuous rigid structure  200 . In one embodiment, the system of top closure straps comprises a first top closure strap  435  affixed to the top surface  425  of the lid  400  such that both free ends hang beneath the closed lid  400 , and a second top closure strap  440  crisscrossing the first closure strap and having a first end affixed to the inelastic wrap tray  300  and a second end hanging freely beneath the closed lid  400 . The second top closure strap  440  may be affixed to the inelastic wrap tray by any means such as, but not limited to stitching, gluing, riveting, or stapling. In a preferred embodiment, the second top closure strap  440  is securely stitched onto the inelastic wrap tray  300  to prevent any give, or movement, under tension. The first top closure strap  435  and second top closure strap  440  may be affixed to the top surface  425  of the lid  400 , and outer surface of the planar side of the continuous rigid structure  200 , by any means such as, but not limited to gluing, riveting or stapling. Preferably the first top closure strap  435  and second top closure strap  440 , are adhesively attached to the top surface  425  of the lid  400  and the second top closure strap  440  is also adhesively affixed to the outer surface of the planar side  205  on which it is disposed. 
         [0041]    Permanently adhesively affixing the one or more top closure straps  435 ,  440  prevents the formation of any attachment induced holes through or divots into the single-walled lid  400  and double-walled continuous rigid structure  200  such that no zones of structural weakness are formed in those members. In a preferred embodiment, the one or more top closure straps  435 ,  440  are permanently adhesively affixed to the lid  400  and are wear resistant and reusable precluding the need for closing the lid with destructive tape that delaminates and degrades fiberboard upon removal. Preferably, the one or more top closure straps  435 ,  440  are inelastic, collapsible, durable and weather resistant, like the inelastic wrap tray  300 . The one or more top closure straps  435 ,  400  therefore may be manufactured from one or more flexible, strong, inelastic materials such as, but not limited to, woven polypropylene, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. Preferably the one or more top closure straps  435 ,  400  are flat, wide strips of material having a low modulus of elasticity, a high yield strength and little thickness so as to maintain the low profile of the collapsible container  100  and so as to prevent any snagging or tearing during handling, transport and use. 
         [0042]    In the described embodiment having at least two top closure straps  435 ,  440  disposed on the lid  400 , the free end of the second top closure strap  440  and the free ends of the first top closure strap  435  are adapted for engaging with at least three respectively aligned side closure strips  250 ,  255 ,  260  affixed respectively to the outer surfaces of three consecutive planar sides  210 ,  215 ,  220 . The at least three side closure strips  250 ,  255 ,  260  each have a first end affixed to the inelastic wrap tray  300  and a second end terminating in an inwardly facing closed retention loop  265 ,  270 ,  275  disposed at the top rim  222  of the container. In one embodiment, depicted in  FIGS. 4B and 4C , a fourth, independent inwardly facing closed retention loop  280  made of the same type or types of materials from which the at least three side closure strips  250 ,  255 ,  260  are made, is securely, permanently affixed between the hingedly attached flap  405  and the outer surface of the “hinge side” planar side  205  to which the lid  400  is affixed. The fourth, independent inwardly facing closed retention loop  280  may be affixed by any means such as, but not limited to stitching, gluing, riveting, or stapling. Similarly, and like the second top closure strap  440 , each of the at least three side closure strips  250 ,  255 ,  260  is affixed at one end to the inelastic wrap tray  300  by any means such as, but not limited to stitching, gluing, riveting, or stapling. In a preferred embodiment, the at least three side closure strips  250 ,  255 ,  260  are securely stitched onto the inelastic wrap tray  300  to prevent any give, or movement, under tension. Additionally, the at least three side closure strips  250 ,  255 ,  260  are affixed to the outer surfaces of the continuous rigid structure  200  by any means such as, but not limited to gluing, riveting or stapling. Preferably the at least three side closure strips  250 ,  255 ,  260  are adhesively, permanently attached to the outer surfaces of the continuous rigid structure  200 . 
         [0043]    Permanently adhesively affixing the at least three side closure strips  250 ,  255 ,  260  prevents the formation of any attachment induced holes through the double-walled continuous rigid structure  200  such that no zones of structural weakness are created during manufacture and assembly of the collapsible container  100 . The at least three side closure strips  250 ,  255 ,  260  are permanently affixed to the continuous rigid structure  200  wear resistant and reusable. Preferably, the at least three side closure strips  250 ,  255 ,  260  are inelastic, collapsible, durable and weather resistant, like the inelastic wrap tray  300 . The at least three side closure strips  250 ,  255 ,  260  therefore may be manufactured from one or more flexible, strong, inelastic materials such as, but not limited to, woven polypropylene, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. Additionally, in one embodiment, the fourth, independent inwardly facing closed retention loop  280  is manufactured from the same material as the at least three side closure strips  250 ,  255 ,  260  and their inwardly facing closed retention loops  265 ,  270 ,  275  formed at the ends thereof. Preferably the at least three side closure strips  250 ,  255 ,  260  are flat, wide strips of material having a low modulus of elasticity, a high yield strength and little thickness so as to maintain the low profile of the collapsible container  100  and so as to prevent any snagging or tearing during handling, transport and use. 
         [0044]    Securing the lid  400  in a closed position over the continuous rigid structure  200  requires connecting the free ends of the one or more top closure strips  435 ,  400  to the at least three side closure strips  250 ,  255 ,  260 . Each of the at least three side closure strips  250 ,  255 ,  260  comprises an attachment means located along the length of each of the side closure strips  250 ,  255 ,  260  at a point above the inelastic wrap tray  300  and below the top rim  222  of the continuous rigid structure so that a gap exists between the free end of each of the top closure straps  435 ,  440  and the at least three side closure strips  250 ,  255 ,  260 . This enables tensioning the top closure straps  435 ,  440  and the at least three side closure strips  250 ,  255 ,  260  prior to connecting those aligned elements to secure the lid  400  tightly in a closed position. In the embodiment of  FIGS. 1 through 3B , the free end of each of the at least three side closure strips comprise a lower eyelet  297  formed therein and each of the free ends of the top closure straps  435 ,  440  each comprise an upper eyelet  445  formed therein. In the embodiment of  FIGS. 4A through 5 , each of the at least three side closure strips  250 ,  255 ,  260  comprises an outwardly extending loop  299  formed along the length thereof and having a lower eyelet  297  formed therein. In both of these embodiments, a plurality of ties  285 ,  290 ,  295  may be looped through the lower eyelets  297  and upper eyelets  445  to secure the lid  400  to the continuous rigid structure  200  and securely seal the collapsible container  100 . 
         [0045]    Although the depicted embodiments show an eyelet and tie closure system, other means of secured closure are possible. For example, the outwardly extending loop  299  might retain therein a metal ring to which an aligned top closure strap may tie. In other embodiments, the top closure straps  435 ,  440  and/or side closure strips  250 ,  255 ,  260  may comprise a buckle closure system or snap-lock closure system with one component of each mating system disposed on each top closure strap  435 ,  440  and the other component of each mating system disposed on or integrated with each of the at least three side closure strips  250 ,  255 ,  260 . In these alternate embodiments, the top closure strap  435 ,  440  and at least three side closure strips  250 ,  255 ,  260  may be longer or shorter than depicted in the embodiments of  FIGS. 1 through 3B  and  4 A through  5 , depending on the type of closure mechanism implemented. 
         [0046]    In addition to contemplating multiple attachment means for securing the lid  400  in a closed position, the present invention contemplates alternate embodiments of the strap and strip closure system. For example, the number and placement of top closure straps and side closure strips may vary in alternate embodiments. For example, in one embodiment (not shown), the collapsible container  100  may comprise only one top closure strap attached at one end to the inelastic wrap tray  300  and hanging free at the other end for attachment to a single side closure strip for maintaining the lid  400  in a closed position. In another embodiment (not shown), the lid  400  of the collapsible container  100  may comprise only one top closure strap disposed on the top surface  425  thereof and hanging free at both ends for attachment to two side closure strips disposed on opposed outer planar surfaces of the continuous rigid structure in alignment with the free ends of the top closure straps. 
         [0047]    Turning now to an embodiment of the present invention further comprising additional means for secure closure of the lid  400  and containment of contents within the collapsible container  100 ,  FIGS. 4B and 4C  clearly depict an embodiment of the present invention comprising a truss member  600  that prevents top rim  222  of the continuous rigid structure  200  from bulging beyond the footprint of the lid  400 . The truss element  600  is an inelastic, closed loop that passes through each of three inwardly facing closed retention loops  265 ,  270 ,  275  and a fourth, independent inwardly facing closed retention loop  280 . The truss element  600  may be made from robust, wear resistant materials such as, but not limited to, polypropylene or polyester. The truss element  600  is fed through each of the three inwardly facing closed retention loops  265 ,  270 ,  275  and the fourth, independent inwardly facing closed retention loop  280 , tensioned and bound end-to-end or with free ends overlapping to form a securely tensioned closed loop. The ends of the truss element  600  may be bound by methods such as for example, but not limited to, sonic welding, stapling, riveting, tying, gluing or thermally bonding. 
         [0048]    The truss element  600  therefore prevents the top rim  222  of the continuous rigid structure  200  from bulging under load conditions. Additionally, because the at least three inwardly facing closed retention loops  265 ,  270 ,  275  and the fourth, independent inwardly facing closed retention loop  280  are short, unobtrusive, and disposed directly adjacent the top rim  222 , the truss element  600  disposed therethrough is tensioned about the periphery of the collapsible container, thereby providing sufficient clearance for loading and unloading contents into and out of the collapsible container  100 . If the top rim  222  were to bulge, that would affect proper secure closure of the lid  400 . Holding the top rim  222  within the footprint of the lid  200  prevents loss of contents or creation of bulged openings at which moisture or debris could fall into the collapsible container  100 , contaminating and/or damaging contents. 
         [0049]    Furthermore, threading the truss element through each of the three inwardly facing closed retention loops  265 ,  270 ,  275  and the fourth, independent inwardly facing closed retention loop  280  precludes any necessity for puncturing the continuous rigid structure  200  to accommodate the tensioned truss element  600 . Prior art containers and bags require puncturing the sidewalls of those assemblies, thereby creating zones of weakness at which the structures could stretch, tear and/or allow loss of content. In some prior art devices having trusses threaded therethrough, additional hole reinforcements and encapsulating structures are required to shield against stretching, tear, seepage and loss of contents. Those additional structures add complexity to the manufacturing process of those devices, add weight to the completed container assemblies, and prevent collapse of those structures to a low profile, planar state as compared to the collapsible container  100  of the present invention which requires fewer bulky components which achieving robust load bearing capabilities. 
         [0050]    Turning now to an embodiment of the present invention comprising a liner,  FIGS. 4B and 4C  depict an impervious liner  700  pre-installed within the interior of the collapsible container  100 . In one embodiment, the liner  700  is form-fitted to the four planar sides  205 ,  210 ,  215 ,  200  of the continuous rigid structure  200  and uniformly, permanently affixed thereto by glue, epoxy, resin or any other adhesive that is known in the art. The liner  700  is affixed to the four planar sides  205 ,  210 ,  215 ,  200  such that the liner  700  is coplanar with each of the four planar sides  205 ,  210 ,  215 ,  200 . That is, the liner  700  is affixed across all of each interior surface of the four planar sides  205 ,  210 ,  215 ,  200 . In another embodiment, the liner  700  is tacked to the inner surfaces of the four planar sides  205 ,  210 ,  215 ,  200 . For example, the liner  700  may be tacked about the top rim  222  of the collapsible container  100  and in one or more spots closer to the bottom member  325  of the collapsible container so that the liner remains in place without puckering, slipping or folding in on itself during filling and evacuation of the collapsible container  100 . The liner  700  is preferably composed of a water resistant or water proof synthetic material that is also resistive to degradation by temperature and corrosive compounds. For example, the liner  700  may be manufactured from materials such as, but not limited to, polyurethane, polyethylene, polyethylene film, polymethylpentene (PMP), polypropylene, or nylon. 
         [0051]    In one embodiment, the liner  700  may be a disposable type liner easily removed and replaced with a clean, new liner  700 . Additionally, a sturdy but impermanent retaining feature (not shown) may be disposed on the inner surface of the planar surfaces  205 ,  210 ,  215 ,  220  and/or the bottom member  325  for retaining a disposable liner  700  within the drum  100 . For example, in one embodiment, the retaining feature may be a Velcro® system, with a sizeable Velcro® panel secured to the inside surface of the bottom member  325  and a mating Velcro® portion secured to the liner. Securing at least one Velcro® panel on at least a third of the inner surface of the bottom member  325  enables retention of the disposable liner  700  during contents evacuation. As one of skill in the art will recognize, other retention systems are capable of producing the same result such as but not limited to snaps, zippers, hook and latch, tie downs, and static charge. Such liners enable transport of hazardous and/or liquid materials without degrading the components of the collapsible container  100  and thereby increase the potential number of reuses of a collapsible container  100 . 
         [0052]    Turning now to  FIG. 5 , in all embodiments of the present invention, the collapsible container  100  collapses to a low profile planar structure for easy handling and compact stacking for storage and transport.  FIG. 5  illustrates the collapsible container  100  in a state of collapse, with the collapsible container  100  buckled at the score lines  225  for compression like a bellows. The lid  400  is folded back 270 degrees from its closed position so that the top surface  425  contacts the outer surface of the “hinge side” planar side  205  of the continuous rigid structure  200 . The fully integrated lid  400  therefore remains attached during collapse and storage of the collapsible container. This eliminates potential for loss of that permanently attached member, eliminates a need for re-securing the lid  400  to the continuous rigid structure  200  during each use of the collapsible container  100  and establishes a mechanism for an efficient, single movement to close the hingedly attached lid  400  atop the expanded collapsible container  100  during use. Unlike existing semi-rigid containers, the collapsible container  100  of the present invention is collapsible into a small volume, low profile, substantially planar state for easy, efficient storage and transport. 
         [0053]    The collapsible container  100  of the present invention as described herein provides a number of tangible benefits over the existing rigid and semi-rigid containers known in the art. The collapsible container  100  of the present invention is rigid enough for stacking, storing and transporting a variety of materials that other semi-rigid containers cannot handle. Moreover, unlike the rigid metal containers, the collapsible container  100  of the present invention can be collapsed from a substantially cubic volume into a substantially flat square for easy stacking and storage. 
         [0054]    It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.