GB2141107A - Composite container - Google Patents

Abstract

A composite container comprises a pair of rigid panel members 14, 16, means 18 for maintaining the panels 14, 16 in a face to face spaced apart parallel relationship, a flexible container 12 disposed between the panels 14, 16 and secured thereto, a closeable loading port 152, 154 in the flexible container 12, and a closeable discharge opening in the container. <IMAGE>

Description

SPECIFICATION Composite container This invention relates to bulk containers and, more particularly, to such containers in which a flexible inner container is supportable by a rigid outer frame-work.

There have been a number of major difficul ties in respect of transport and storage of bulk cargoes, particularly hazardous liquids. These include such problems as susceptability to shock, container rupture and the like. Such problems of a general nature present them selves in all such applications. In addition, specific applications will present further diffi culties arising out of conditions unique to such applications.

One such particular applications arise in the context of marine oil spills and centres on the difficulty of the removal of oil from the spill site. Such removal, following capture and pick-up of spilled oil, has generally been ac complished to date by the use of the standard 45 gallon oil drum. There has to date been no economical alternative to this method. The result of this lack of suitable transport means has resulted in a factor in the area of 70% of expended time on an oil spill site being consumed in the transport of oil that has already been recovered from the water.

It has heretofore been the case that an oil recovery vehicle will be supplied with empty oil drums, will proceed to the oil recovery area, recover sufficient oil to fill the drums, then return to an offloading site for removal of the filled drums and reloading with empty ones. It is this period from the time at which the oil drums are filled to the time at which the intermediate steps can be completed and recovery recommenced that time is lost.

The present invention addresses itself in general to the problem of transport of difficult or hazardous bulk materials, particularly liquids. An example of a specific application of this new technology is in the field of marine oil spill clean up.

As indicated in applicatant's copending Canadian application for Letters Patent Serial No. 376,589, applicant is unaware of any useful prior art. It has generally been the case to the best of applicant's knowledge that solid sided containers are generally used for shipment of difficult or hazardous bulk materials.

The present invention provides a modular system in which many of the transport problems discussed above have been overcome.

The invention combines aspects of the safety and durability of a flexible container with the same advantage offered by some aspects of a rigid container. The resulting device provides a container offering distinct advantages over either predecessor type.

Accordingly, in one broad aspect the invention provides a composite container compris ing a pair of rigid panel members, means for maintaining the panels in a face to face spaced apart parallel relationship, a flexible container disposed between the panels and secured thereto, a closeable loading port in the flexible container, and a closeable dis charge opening in the flexible container.

It has now been discovered and confirmed in testing that there are significant advantages to be obtained from a container which combines aspects of solid sided and flexible containers. An advantage in general utility is the ease of handling of solid sided containers by fork lift trucks and the like.

In the present invention a flexible container is supported between at least two rigid side panels. The panels are held in parallel spaced relationship by end support members.

In a preferred embodiment, the end support members are detachably secured to the rigid side panels and can be removed to allow the container to collapse for empty storage or transport. The end supports may be reattached to secure the unit in the collapsed position.

The solid panels and the flexible container are preferably joined near the respective longitudinal edges by an interlocking slide and track arrangement. Such an arrangement simplifies the assembly process.

Inlet and outlet means to and from the flexible container may be varied to suit the particular application. Generally a standard loading port will be included along with a venting port where desirable.

In the case of the marine spill clean-up operation, it is essential that the unit be capable of offloading quickly and completely a very viscous material such as cold Bunker C oil. A convenient means of doing so has been found to be the provision of a very substantial opening in at least one end of the container.

In a preferred embodiment the container includes an extension on at least one end which when closed folds against the end of the container and, when open, extends into a chute-like structure. The outer end of this structure is in the preferred case provided with a slide fastener across the full width of the end. Alternatively, a squeeze clamp means may be employed extending across an opening in the end of the extension.

The folded end extension can be held in place in any suitable manner, but is preferably secured behind a quick-release structure which, when secured against the end of the container, will hold the folded extension in place, but which, when released, allows the end extension to unfold. The arrangement of the fold and the end structure may be such as to allow the slide fastener or squeeze clamp to be exposed when in the closed position so that the fastening may be released prior to release of the folded end structure. Thus, when the end structure is released, the exten sion will unfold already fully open.

The container is preferably unloaded by having one end lifted vertically into the air, as by a crane, then following the opening procedure just described. Various intermediate degrees of lifting will also generally allow for complete dumping of the container contents.

Such may be accomplished by a forklift vehicle or the like.

In drawings which illustrate embodiments of the invention, Figure 1 is an exploded isometric of one embodiment of a container according to the invention; Figure 2 is an exploded isometric of a second embodiment of a container according to the invention; Figure 3 is an isometric view of an assembled container according to the embodiment of Fig. 2; Figure 4 is an isometric view of a container according to the invention in a collapsed format.

Figure 5 is an exploded isometric of a panel according to the present invention; Figure 6 is a transverse cross section through a guide tack joint in a container according to the invention; Figure 7 is a cross section similar to that of Fig. 6 through an alternative type of guide track joint; Figures 8 to 13 illustrate detail of the preferred quick-release opening system according to the invention.

While the invention will be described in conjuction with the illustrated embodiments, it will be understood that it is not intended to limit the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

In the following description, similar features in the drawings have been given similar reference numerals.

With reference to the drawings, the composite container 10 includes an enclosed flexible container 1 2 and the two rigid panels 14 and 1 6. The structural members 1 8 secure the panels 14 and 16 in spaced parallel planes.

In the preferred embodiment the panels 14 and 1 6 are constructed with hollow structural sections 20 along the longitudinal edges, and the structural members 1 8 are provided with corresponding extensions 22. In the assembled operating condition illustrated in Figs. 1 and 2, the extensions 22 slide into the members 1 8 and are secured there as by bolts 24 (not shown).

In the preferred embodiment the composite container is collapsible by removal of members 18 and folding of flexible container 12.

In this configuration as illustrated in Fig. 4, members 1 8 are preferably secured to the outside edge of the structural sections 20, using bolts 24 (not shown) threaded openings provided for the purpose as at 25.

In the preferred case the composite container is buoyant and, preferably, buoyancy chambers 26 are provided integral with the panels 14 and 16 (see Fig. 5). These cham bers may and preferably will contain a flotation material 27 such as polyurethane foam.

The flexible container 12 and the panels 14 and 1 6 are secured together along their longitudinal edges by a flange system. The preferred system is that illustrated in Fig. 1 and detailed in Fig. 6 wherein the panels 14 and 1 6 include flanges in a guide track configuration. The most preferred case is that wherein guide tracks 28 are configured to include a longitudinally extending cylindrical slide way 30 having a slot 32 along the length of the slide way.

As illustrated, the tracks 28 extend along the inwardly facing sides of the panels 1 4 and 1 6 adjacent the outside edges 34 thereof.

Cooperating with the tracks 28 are flanges 36 on the outer sides 38 of the flexible container 1 2. As illustrated in Fig. 1, the flanges are preferalby of the same flexible material as container 1 2 and constructed in a looped configuration in which the exterior diameter of the loop 40 is such that, when in a cylindrical position, the loop 40 can be accommodated in the slide way 30.

In order to ensure maximum strength in the resulting joint, a rod 42 or cable is inserted longitudinally within the loop 40. Clearly the diameter of the rod will be less than the inside diameter of the loop when the latter is in a cylindrical position. As well, the system is designed such that the rod 42 will be larger in diameter than the distance "d" across the slot 32.

Other configurations of the flange system will be suitable, and those are preferred which utilize a slide way type track arrangement to facilitate quick assembly and to promote avoidance of local stress points. For example, in an alternative embodiment, as illustrated in Fig. 7, a flange 43 of a solid material, such as PVC, is welded to the flexible container 1 2 to cooperate with slide track 30. The flange 43 is preferably segmented to allow for flexibility and foldability of the flexible container.

Depending on the application for which the container is intended, the discharge opening may take many forms. For example, where light liquids which do not present cleaning difficulties are to be carried, a simple sealable port may be sufficient. However, where the container is to be utilized in situations such as oil spill Bunker C oil, or the like, discharge of the material from the container becomes a much more serious problem. The material may be very viscous and difficult to pump or pour, and may, as well, present difficult cleaning problems in the container. For this reason a preferred discharge arrangement is one which will provide a substantially unrestricted opening to facilitate rapid discharge and easy cleaning.

The preferred discharge arrangement, as illustrated in Fig. 1, includes a foldable exten sion 44 to the end of the flexible container 1 2. The extension 44 includes a slide fastener 45 (see Fig. 3) extending across an opening 47 (not shown) adjacent or at the extreme outward edge 46 of extension 44; or alternatively may be provided with a squeeze clamp closure for opening 47.

The extension may assume various configu rations as may be found suitable in a particu lar case, but a triangular configuration 48 bounded by the end of flexible container 12, an extension 50 of one side of flexible unit 12, and the angled face 52; and.wherein the extension 50 is approximately equal to and preferably greater in length than the height 54 of flexible container 1 2 has been found most suitable. In the closed position the extension 44 can then be conveniently folded across the end of flexible container 1 2 so that the slide fastener 45 will lie adjacent the edge face 56 of panel 14.

A retaining means such as the end structure 58 may be provided to maintain the extension 44 in the folded position. This structure 58 may carry some or substantially all of the pressure of the container contents. This will prevent stress on the slide fastener or the opening and allow the fastener or other closure means to be readily openable with the extension 44 still in the folded position.

To facilitate emptying, the end structure 58 ought to be easily removable. In one embodiment, as illustrated in Fig. 1, the end structure 58 is hingedly connected to the container 10 and is held in the closed position by a quick release mechanism.

With reference to Fig. 1, the end structure 58 comprises a pair of rollers 60 and 62 and the panel 64, preferably flexible. The panel 64 is of looped configuration. In use the rollers 60 and 62 are inserted through the looping ends of panel 64.

The roller 62 is joined to the container structure in a hinged connection. A pair of pins 68 (not illustrated) fixed to the members 18 extend into roller 62 to form the pivotal connection for the hinged movement.

The roller 60 is similarly held in place by a pair of pins 70 and 72. The pin 70 shown in roller 60 actually is fixed to the member 1 8 in a manner similar to pins 68. The pin 72, however, in one embodiment is actually fixed to and held in place by a quick release mechanism comprising the lever 74 and the pin support member 75. Lever 74 is pivotally connected to member 1 8 about the point 76 in the slot 78 (not visible behind wall 82). In the closed position the lever 74 lies flush between the walls 80 and 82 of the member 18. The member 75 is pivotally connected to lever 74 at 77 below the pivot point 76.

In use the extension 44 is folded up against the end of the container and the hinged end structure 58 is rotated up against the folded extension. The end of roller 60 is placed over the pin 70 and the opposite end of roller 60 is aligned with the operative position of the pin 72. The lever 74 is rotated toward roller 60 until the pin 72 engages in the end of roller 60. At this point the lever 74 will be flush against member 1 8. The extension 44 is then held in the folded position in such a way that the pressure of the container contents, when it is filled, will be taken by the end structure 58 rather than the by slide fastener 45.

To empty the container by a dumping action, where required, the container is preferably lifted to a vertical position with the end structure 58 parallel to ground. The arrangement of parts is such that slide fastener 45 is accessible above roller 60. The slide fastener 45 is then opened. Finally, the lever 74 is pulled out to disengage the pin 72. The roller 60 then begins to drop away from pin 72 and simply slides off of pin 70. The end structure 58 falls away about hinge/roller 62 and the folded extension 44 is unfolded by the pressure of the container contents. The pressure of the container contents will result in the opening assuming an approximately circular configuration. Very rapid dumping of the container contents will be achieved.

In a further embodiment the pin 72 is retained in roller 60 and is spring biased to protrude therefrom. The pin then simply snaps into the operative position through an opening provided in member 1 8. The lever 74 is pivotted to abut against the end of pin 72 and moves it against the spring bias in order to release the pin 72 and so to release the roller 60 and the extension 44 An alternative retaining means, and the preferred configuration, is illustrated in Fig. 2.

In that embodiment the end support structure comprises the two rollers 84 and 86, one of which is calmed or otherwise extended as at 88. The roller 84 is simply a protective structure which acts as will be described below to protect the flexible container 1 2 from undue strain in the general area of the edge 90 of the panel 1 6 during the opening operation.

It is the cammed roller 86 that controls the unfolding of the extension 44. The roller 86 is mounted for rotation ona rod 92 which is in turn mounted through holes 94 and 96 in the webbing 98 and 100 respectively of members 18. The rod 92 is fixed at one end to a plate 102 having a series of studs 1 04. The webbing 98 contains a series of holes 106 of a pattern corresponding to the series of studs 104 of plate 102. Thus the rod 92 and the plate 102 may be positioned such that the studs 104 extend through the holes 106.

The roller 86 is provided with a plate 108 secured to the end thereof, which plate contains a series of holes 110 corresponding in pattern to the series of studs 1 04.

When the series of studs 104 is positioned to extend through the holes 106, and the roller 86 is in position between the members 18, the studs 104 will also extend into the holes 110 to lock the roller 86 against rotation.

The opposite end of the rod 92, when the extension 44 is in the folded position, as in Fig. 3, is longitudinally biased or secured to maintain the plate and stud locked position described above. The securing means could be simply a cotter pin or the like, as illustrated in Figs. 10 and 11.

In those figures a lever 11 2 pivotted about the pin or bolt 11 4 is also pivotally connected to the end of the rod 92 by means of the pin 11 6. The lever 112 is held in position adjacent member 1 8 by means of a cotter pin or the like arrangement 118.

In this embodiment the extension 44 is provided with a flange 1 20 which is preferably strengthened by means of a cable or rod 122 secured longitudinally within the flange (see Fig. 8). When the extension 44 is in the folded position, and the roller 86 is secured, the dimensions chosen and the orientation of the cam 88 are such that the cam will lie adjacent the top edge of the panel 14, and the flange 1 20 will bring up against the cam 88. The extension 44 will thus be held in the folded position. Similarly, the position of the slide fastener 45 in the extension 44 is such that the slide fastener will be presented for operation above the flange 120.

In order to empty the container by means of the extension 44, the slide fastener is first opened. The cotter pin locking arrangement 118 is then released and the lever 11 2 pivotted outward. The rod 92 is thus moved longitudinally, along with the plate 102 and the studs 1 04. When the studs 104 have been moved sufficiently to clear plate 108, the pressure of the flange 1 20 on the cam 88 will cause rotation of the roller 86. When the cam 88 has moved sufficiently to clear the area adjacent the panel 14, the spacing "s" between the outside surface 1 22 of the roller 86 and the end 56 of panel 14 is sufficient to allow the flange 1 20 to pass through.Subsequently, if necessary, the end of flexible container 1 2 will flex to allow the flange 1 20 to pass. The extension 44 then unfolds and the contents empties.

The preferred arrangement for the embodiment just described is one where the rod 92 is spring biased to maintain the rod 92 in the position in which the studs 104 engage the holes 110 to maintain the roller 86 in secured position against rotation. Such an arrange ment is illustrated in Figs. 1 2 and 1 3.

The spring 1 24 is fixed at one end 126 to the pivot pin 114, and the opposite end 1 28 is engaged in an opening 1 30 in rod 92. The rod 92 is thereby biased toward the lever 11 2 but is limited in movement by reason of the abutment of the end 1 32 of the rod 92 against the lever 11 2. The rod 92 is locked against movement counter to the spring bias by reason of the end 1 28 of spring 1 24 abutting against the member 1 8.

Meanwhille, the lever 11 2 is maintained in position adjacent member 1 8 by reason of abutment at 1 34 against the end 1 32 of the rod 92.

In order to release the roll 86 to rotate and in turn free the flange 1 20 and the extension 44, the end 1 28 of the spring 1 24 is removed from the opening 1 30 in rod 92 and inserted into the second opening 136. The lever 11 2 is then rotated against the end 1 32 of the rod 92 to move the rod 92 longitudinally against the tension of spring 1 24. The degree of movement is limited by the length and profile of the end 1 38 of the lever 11 2 and by the end 128 of the spring 1 24 abutting against the web 1 39 of member 1 8.

The permitted distance of movement "x" is sufficient to disengage the studs 104 from the holes 110 to thereby allow rotation of the roll 86 and release of the flange 1 20 and the extension 44.

To refoid and secure the extension 44, the process is generally reversed. The extension is folded and the flange 1 20 positioned above roller 86. The lever 1 2 is then swung out to maintain studs 104 out of interference with the plate 108, and the roller 86 rotated to align the studs 104 with the holes 110. The cam 88 is then in position to maintain the flange 1 20 in position. The lever 11 2 is then released and the spring 1 24 moves the rod 92 longitudinally to engage studs 104 in holes 110. The end 128 of the spring 1 24 is then removed from the opening 1 36 and reinserted into opening 1 30 to lock the mechanism against inadvertent opening.

In both of the embodiments described in Figs. 10 and 11, and 12 and 13, the lower roller 84 serves to aid in relieving the flexible container 1 2 from some of the stress accompanying the sudden opening. The flexible container 1 2 is preferably provided with a flange 140 containing a cable or rod 142 (not shown) which is inserted between the roller 84 and the end 146 of panel 1 6 during assembly of the container. The roller 84 is positioned to prevent subsequent removal of the flange. In opening the container this flange absorbs much of the shock of the extension 44 falling and opening when the opposite end 148 of the container is lifted for emptying. The roller 84 also provides a smooth surface to be impacted by the swinging bottom 1 50 of the extension 44 to thereby avoid possible abrasion.

In a further embodiment of the opening mechanism just described, the slide fastener 45 and/or the flange 1 20 is omitted and the abutting faces of flexible container 1 2 and the extension 44 are provided with anti-slip means in the area of contact of cam 88. The folded extension is then locked in closed posi tion by reason of the pressure of cam 88 locking the said anti-slip areas together and against the end of panel 1 6. Such non-slip means might be a set of interlocking teeth or protrusions. A locking bar or clamp may alter natively be interposed between the cam 88 and the folded extension.

Many variations on this end closure can be contemplated which are within the spirit and scope of the invention and which would be suitable for the quick release dumping function.

For pumped or suction unloading, ports may be provided as necessary such as loading ports 1 52 and 1 54. Similarly, pressure re lease vents may be provided.

Preferably, loading ports 1 52 and 1 54 will be provided on both exposed sides of the flexible container 1 2. When floated for oil spill cleanup, the buoyancy of the panels 1 4 and 1 6 will cause the container to orient itself in the water with these panels at the sides and with the exposed sides of the flexible container 1 2 forming the top and bottom. The availability of loading ports on both sides makes it unnecessary to orient a specific side to the top when placing the container in the water.

Hollow members 1 56 and 1 58 may be conveniently provided on one or both of panels 14 and 1 6 with standard spacing to accommodate a forklift.

Thus it is apparent that there has been provided in accordance with the invention bulk containers and, more particularly, such containers in which a flexible inner container is supportable by a rigid outer frame-work that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended

Claims (42)

claims. CLAIMS

1. A composite container comprising: a pair of rigid panel members; means for maintaining said panels in a face to face spaced apart parallel relationship; a flexible container disposed between said panels and secured thereto; a closeable loading port in said flexible container; and a closeable discharge opening in said container.

2. The composite container of claim 1 wherein said means comprises at least four structural members, each extending from a respective corner of one said panel to a corresponding corner of the second panel.

3. The composite container of claim 1 wherein each said panel member includes a pair of guide tracks and said flexible container includes a flange member corresponding to each said track, whereby said panels and said flexible container may be secured together by securing said flange in said guide track, thereby leaving two covered sides and two exposed sides of said flexible container.

4. The composite container of claim 3 wherein the said guide tracks comprises a substantially enclosed slide way with a narrow longitudinally extending slot therethrough.

5. The composite container of claim 4 wherein the said flange comprises a narrow neck portion adjacent said flexible container and a thickened portion remote from said flexible container, said thickened portion adapted to be received into said slide way to thereby secure said flexible container to said panels.

6. The composite container of claim 5 wherein said thickened portion includes a longitudinally extending central opening therethrough.

7. The composite container of claim 4 wherein the said flange member comprises a longitudinally extending looped configuration, said looped flange adapted to be received into said slide way to thereby secure said flexible container to said panels.

8. The composite container of claim 6 or 7 including, in addition, for each said flange, an elongated rod or cable section adapted to be inserted into said central opening to lock said flange against pulling transversely out of said slide way.

9. The composite container of claim 5 wherein the said flange is of the same material as the said flexible container.

1 0. The composite container of claim 5 wherein the flange is comprised of a solid material fixed to said flexible container.

11. The composite container of claim 10 wherein the said flange is segmented.

1 2. The composite container of claim 2 wherein each said panel includes adjacent each corner thereof a recess for receiving said structural members.

1 3. The composite container of claim 1 2 wherein each said structural member includes a lateral extension at each end thereof and wherein each said panel is provided with means for receiving said extensions, whereby said structural members may be secured to said panels.

1 4. The composite container of claim 1 3 wherein each said panel includes hollow structural sections extending along at least the longitudinal edges thereof, and wherein the ends of said sections are open to receive said extensions.

1 5. The composite container of claim 14 wherein said extensions and said sections are provided with mutually aligning openings for insertion of fastening devices, whereby said extensions may be secured in said sections.

1 6. The composite container of claim 2 wherein the said container includes a foldable extension to at least one end thereof, and said discharge opening is located at the end of said extension.

1 7. The composite container of claim 1 6 wherein the said extension can be folded from an open configuration to a closed configuration in the latter of which said opening is located adjacent one of said panel members.

1 8. The composite container of claim 1 7 wherein the said extension includes a slide fastener extending across the said opening.

19. The composite container of claim 17 wherein the said extension is provided with squeeze clamp means extending across the said opening for releasably closing the opening.

20. The composite container of claim 1 8 wherein the opening is located in said extension such that, when the extension is in the folded position, the said opening is adjacent and parallel to the end edge of a first of said panels members.

21. The composite container of claim 20 wherein the said extension comprises an elongation of one of the said covered sides of the said flexible container by a distance approximately equal to or greater than the height of the said exposed sides; an angled section extending from the edge of the opposite said covered side to meet the said elongation; and triangular side panels to enclose the extension.

22. The composite container of claim 21 wherein the said opening is located at or near the line of joining of the said elongation and the said angled section.

23. The composite container of claim 1 6 including a retaining structure to maintain the said foldable extension in a folded position.

24. The composite container of claim 23 wherein the said retaining structure is so constructed as to support substantially all of the pressure on the end of the said flexibel container when the latter is filled, whereby the said slide fastener is under very little said pressure.

25. The container of claim 24 wherein the said retaining means comprises a hinged end structure adapted to swing open to allow the said extension to unfold.

26. The container of claim 25 wherein the said end structure comprises first and second transverse members and an intermediate member joined to the said transverse members, said first transverse member hingedly secured between and toward the end of two of said structural members and said second transverse member adapted to be releasably secured between and toward the opposite end of said two structural members.

27. The container of claim 26 wherein the said first and second members are mounted on pins or rods passing between the said first and second members and the said structural members, at least one of said pins or rods adapted to be at least partly withdrawn from said second member whereby said second member is free to move from the closed position as said first member rotates about its associated pins or rod.

28. The container of claim 26 wherein said intermediate member is a panel having two integral closed channels running transversely across each end thereof, and wherein said transverse members extend through respective ones of said channels.

29. The composite container of claim 28 wherein the said transverse members are mounted on pins and wherein one of said pins mounting said second member is operatively connected to a pivotted lever whereby the said pin may be inserted or withdrawn from the mounting position by movement of the said lever.

30. The composite container of claim 20 wherein the said extension includes a transverse thickened section adjacent the said opening and wherein the said container includes retaining means for maintaining the said extension in the folded position, said retaining means comprising a transverse member extending across the end of said container adjacent the end of said first panel member and mounted for rotation on a rod, said rod extending between and through two of said structural members; said transverse member including a cam section extending longitudinally of said member; the relative spacing between said transverse member and said end being such that said folded extension and said thickened section normally pass therebetween but will be restrained form so passing when said transverse member is rotated to a position where the cam section is adjacent the said end; and wherein said retaining means includes means for releasably locking said transverse member against rotation.

31. The composite container of claim 30 wherein said thickened section comprises a flange.

32. The composite container of claim 31 wherein said flange includes a narrow neck portion adjacent said container leading to a thicker portion remote therefrom.

33. The composite container of claim 32 wherein the said thicker portion is of looped configuration and contains a stiffening member longitudinally within said loop.

34. The composite container of claim 33 wherein said stiffening member is a rod or cable.

35. The composite container of claim 33 wherein said rod is mounted for longitudinal movement and said means for releasably locking comprises, on one end said rod outside a respective one of said structural members a first plate containing at least one stud thereon; on a corresponding end of said transverse member a second plate having at least one opening therein corresponding to said at least one stud; and in said structural member, at least one hole through said member corresponding to said at least one stud; whereby when said rod is longitudinally positioned such that said at least one stud extends through said at least one hole and into said at least one opening in said second plate, the said transverse member is locked against rotation; and including means for longitudinally positioning said rod.

36. The composite container of claim 35 wherein said means for longitudinally positioning said rod includes a lever pivotally connected to one said structural member and at a second pivot point to said rod whereby manipulation of said lever effects longitudinal movement of said rod.

37. The composite container of claim 35 wherein said means for longitudinally positioning said rod includes a spring means biasing said rod against a lever, said lever pivotally connected to said structural member at the end of said rod opposite to said plates, whereby manipulation of said lever effects longitudinal movement of said rod against said spring means.

38. The composite container of claim 1 wherein said panels are buoyant.

39. The composite container of claim 1 wherein said panels contain buoyancy chambers.

40. The composite container of claim 39 wherein said buoyancy chambers contain flotation material.

41. The composite container of claim 40 wherein said flotation material is urethane foam.

42. A composite container substantially as herein described with reference to the accompanying drawings.