Abstract:
A collapsible transport container ( 302 ) comprising a base ( 304 ), a roof ( 310 ), a first and second opposed side wall ( 308, 306 ) rotatable relative to the base ( 304 ) and the roof ( 310 ). Also provided with first connecting member ( 316 ) operably connecting the first side wall ( 306 ) to the roof and second connecting member ( 318 ) operably connecting the second side wall ( 306 ) to the roof ( 310 ). The distance between the point of attachment of first and second connecting member ( 318, 316 ) to the roof ( 310 ) is less than the distance between the point of attachment ( 326, 324 ) of first and second connecting member  326, 324 ) to the first and second side wall ( 308, 306 ). At least part of the connecting member is flexible.

Description:
This application is a United States national phase application of co-pending International Application Number PCT/NL2012/050280, filed Apr. 26, 2012, which claims priority to Dutch patent application number 2006748, filed May 10, 2011, in the Netherlands Patent Office, the disclosures of which are incorporated herein by reference to the extent consistent with the present disclosure. 
     This invention relates to a collapsible transport container having an improved connecting mechanism between the walls and roof of the container, and to a connecting member for such a container. 
     BACKGROUND 
     This invention relates to containers of the kind used for the transport of freight in so-called ‘container-ships’, or by rail or by road. Such containers are made to one of a few internationally agreed sizes. Global trade and distribution imbalances frequently necessitate the transport of empty containers from large consumption markets to regions of mass production and manufacture. In order to alleviate the cost of transporting empty containers, collapsible containers have been developed. These containers can be folded when empty into a collapsed or stowed condition in which they occupy significantly less volume than in their assembled or erected condition, thus allowing for more efficient transportation of the containers when empty. 
     NL1017159, U.S. Pat. No. 4,099,640 and WO-A-2010/151116 describe examples of collapsible goods-shipping containers. 
     Assembly and disassembly of collapsible containers must take place in a safe and reliable manner. Frequently, the size and weight of the container walls are such that heavy lifting equipment such as forklifts must be employed, complicating operation and increasing the burden of assembly/disassembly. It is therefore desirable to simplify as far as possible the procedure for assembly and disassembly of collapsible containers. One known type of collapsible container  102  is illustrated in  FIGS. 1   a  and  1   b  and comprises a base  104 , side walls  106 ,  108  and a roof  110 . The walls  106 ,  108  are hinged to the base  104  at hinges  112 ,  114  such that they may rotate about the hinges and fold onto the base  104 . The roof  110  is connected to the opposed side walls  106 ,  108  via rigid connection members  116 ,  118 , each of which is connected via a first hinge  124 ,  126  to a respective side wall  106 ,  108  and via a second hinge  120 ,  122  to the roof  110 . The connection members may thus pivot about each end, allowing for raising of the roof  110 , pivoting motion of the walls  106 ,  108  beneath the roof  110  and then lowering of the roof  110  onto the collapsed walls  106 ,  108 , as illustrated particularly in  FIG. 1   b . The connection members allow a connection to be maintained between the side walls  106 ,  108  and the roof  110 , during the process of collapsing the walls. 
     It will be appreciated that, during collapsing of the walls  106 ,  108 , the connection members  116 ,  118  pass through an angle approaching 270° with respect to the walls  106 ,  108 . In order to allow for this range of motion, it is necessary to leave considerable clearance around the walls, and this need for clearance impacts on the connectivity between the walls and the roof. In practice, it is extremely difficult to establish a seal between the roof  110  and walls  106 ,  108 , while leaving the necessary clearance, and consequently, the container  102  cannot be made watertight. This is a considerable disadvantage. 
     Another known container type that seeks to address the issue of sealing between the roof and walls of the container is illustrated in  FIGS. 2   a  and  2   b . This container  202  also comprises a base  204 , opposed side walls  206 ,  208  and a roof  210 . The walls  206 ,  208  are hinged to the base  204  at hinges  212 ,  214  such that they may rotate about the hinges and fold onto the base  204 . The roof  210  is connected to the opposed side walls  206 ,  208  via rigid connection members  216 ,  218 . Each connection member comprises a first end which is connected via a first hinge  224 ,  226  to a respective side wall  206 ,  208 . The second ends of the connection members  216 ,  218  are formed as runners  230 ,  232 , adapted to be slidably received within a respective slot or channel  234 ,  236  formed on the roof  210 . According to this construction, it is possible to lift the roof  210 , pivot the side walls  206 ,  208  towards the base  204  and subsequently lower the roof  210  without the need for excessive pivoting of the connection members  216 ,  218 . The connection members merely slide within the slots  264 ,  236  formed within the roof  210 . Owing to this sliding motion, the container can be constructed without the need for large clearance between the walls  206 ,  208  and the roof  210 , and a watertight seal may be obtained between the walls  206 ,  208  and the roof  210 . A further example of a collapsible container of this type is disclosed in FR-A-2699513. 
     Although the container of  FIG. 2  addresses the clearance and sealing issues experienced with the container of  FIG. 1 , other issues of assembly and disassembly are known to arise with this type of container. In order to accommodate the motion required for assembly, the slot and slider system must be relatively complex. In addition, it is necessary to maintain the roof in accurate alignment with the base during assembly and disassembly of the container. Misalignment of the roof with respect to the rest of the container can cause the slider mechanisms to jam during motion, placing excessive forces on the slider joints. In practice, it is extremely difficult to maintain accurate alignment of the roof when lifting, for example with a reach stacker or a crane. The connection members, sliders and hinges must therefore be highly robust to withstand the large loads experienced during assembly and disassembly of the container. Even with extremely robust connections, a trained operator is required and there remains a risk that the connections between the connection members and the roof or the walls will fail. 
     This invention seeks to address some or all of the above mentioned disadvantages associated with known collapsible transport containers. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a collapsible transport container comprising:
         a base;   a roof;   a first and second opposed side wall rotatable relative to the base and the roof and   first connecting member operably connecting the first side wall to the roof and second connecting member operably connecting the second side wall to the roof, wherein the distance between the point of attachment of first and second connecting member to the roof is less than the distance between the point of attachment of first and second connecting member to the first and second side wall and wherein at least part of the connecting member is flexible.       

     The roof may be lifted from the side walls. 
     The connecting member may connect to the roof at a fixed location. 
     The connecting member may connect to the roof via a hinge to allow for pivotal motion between the connecting member and the roof. 
     The connecting member may connect to the wall at a fixed location which may for example be a hinged connection. 
     The connecting member may connect to the roof via a sliding connection. 
     The sliding connection may be formed by a carriage to which the connecting member is attached and which is slidably received within a rail formed on the roof. The carriage may be integrally formed with the connecting member or may be a separate component. The sliding connection may incorporate any appropriate mechanism allowing for sliding motion of the connecting member with respect to the roof, the sliding connection may for example be formed by a wheel formed on an end of the connecting member and received within an appropriate rail formed on the roof. 
     The rail may for example comprise a slot or channel formed within the roof, or may be a separate component attached to the roof. The carriage may be formed as a slider or other sliding connection and may engage with the rail in any appropriate sliding manner, for example being received within the confines of the rail or extending either side of the rail with a bifurcated formation. 
     The connecting member may be connected to the carriage via a hinge. 
     The collapsible container may further comprise a biasing element which may be formed within the rail and may be operable to bias the carriage to a stowed position. 
     The stowed poison of the carriage may be towards a central region of the rail. 
     The biasing element may comprise a return spring. 
     The connecting member may comprise a rigid portion and a flexible portion. 
     The flexible portion may be resilient and may for example be elastic. 
     An end of the rigid portion may be operably connected to the roof and an end of the flexible portion may be operably connected to the wall. 
     The rigid portion of the connecting member may comprise a rigid rod which may for example be hollow. The rod may for example comprise a beam, tube or any other appropriate structure. 
     The flexible portion of the connecting member may comprise one of a cable, rope, chain or strap. 
     A connection between the rigid portion and the flexible portion of the connecting member may be a fixed connection. 
     Alternatively, a connection between the rigid portion and the flexible portion of the connecting member may be a sliding connection. 
     An end of the flexible portion of the connecting member may be slidably received within the rigid portion of the connecting member. 
     The connecting member may further comprise a biasing element, which may be operable to bias the flexible portion of the connecting member towards the rigid portion of the connecting member. The biasing element may be configured to bias the flexible portion to retract within the rigid portion. 
     The biasing element may be housed within the rigid portion of the connecting member and may for example comprise a spring. 
     The spring may be arranged in compression, such that the flexible portion extends through the spring and the spring engages against an open end of the rigid portion. In this arrangement, increasing separation between the flexible and rigid portions places the spring under compression. Alternatively, the spring may be arranged in tension, being connected to a closed end of the rigid portion such that increasing separation between the flexible and rigid portions places the spring in tension. 
     According to another embodiment of the invention, the connecting member may be fully flexible. 
     According to another aspect of the present invention, there is provided a connecting member for a collapsible transport container, the connecting member comprising a rigid portion and a flexible portion, the rigid and flexible portions being operably connected. 
     The rigid portion may be at least partially hollow, and an end of the flexible portion may be received within the hollow rigid portion. 
     The connecting member may further comprise a biasing element, which may be operable to bias the flexible portion to retract into the hollow rigid portion. The biasing element may for example comprise a spring. 
     The invention is also directed to a method to fold a collapsible transport container
         comprising:   a base;   a roof;   a first and second opposed side wall rotatable relative to the base and the roof and   first connecting member operably connecting the first side wall to the roof and second connecting member operably connecting the second side wall to the roof, wherein the distance between the point of attachment of first and second connecting member to the roof is less than the distance between the point of attachment of first and second connecting member to the first and second side wall and wherein at least part of the connecting member is flexible,   by lifting the roof from the first and second opposed side wall, wherein the side walls will pivot towards the base and subsequently lowering the roof, wherein the side walls will further pivot towards the base.       

     Preferably the method is applied to a collapsible container according to the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the following drawings, in which: 
         FIGS. 1   a  and  1   b  illustrate a collapsible container according to the prior art; 
         FIGS. 2   a  and  2   b  illustrate another collapsible container according to the prior art; 
         FIGS. 3   a  and  3   b  illustrate a collapsible container having flexible connecting members; 
         FIGS. 4   a  and  4   b  illustrate another embodiment of collapsible container having flexible connecting members; 
         FIGS. 5   a  and  5   b  illustrate a collapsible container having partially flexible connecting members; 
         FIGS. 6   a  and  6   b  illustrate another embodiment of collapsible container having partially flexible connecting members; 
         FIG. 7  illustrates a partially flexible connecting member; and 
         FIG. 8  illustrates another embodiment of partially flexible connecting member. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     With reference to  FIGS. 3   a  and  3   b , a collapsible container  302  comprises a base  304 , side walls  306 ,  308  and a roof  310 . The walls  306 ,  308  are hinged to the base  304  at hinges  312 ,  314  such that they may rotate about the hinges and fold onto the base  304 . The hinges  312 ,  314  thus define axes of rotation for the walls  306 ,  308 , these axes of rotation being substantially adjacent to the base  304 . The walls  306 ,  308  may have an L shaped cross section, as shown in the Figures, the hinged connection being formed at a free end of the base of the L shaped wall, as illustrated. Alternatively, the walls may have a simple linear cross section. The roof  310  is connected to the opposed side walls  306 ,  308  via flexible connecting members  316 ,  318 , each of which is connected via a first hinge  324 ,  326  to a respective side wall  306 ,  308  and via a second hinge  320 ,  322  to the roof  310  at a fixed location. 
       FIG. 3   a  shows that the distance between the point of attachment of first and second connecting member  318 ,  316  to the roof  310 , i.e. the distance between second hinges  322  and  320  is less than the distance between the point of attachment of first and second connecting member  318 ,  316  to the first and second side wall  308 ,  306 , i.e. the distance between hinges  326  and  324 . Because of this difference in distance the side walls  306 ,  308  will pivot towards the base  304  when the roof  310  is lifted from the side walls  308 ,  306 . When the side walls  308 ,  306  are sufficiently inclined inwards the roof  310  is subsequently lowered and the side walls  308 ,  306  pivot further towards the base  304  to eventually rest upon the base  304  or on any remaining side walls. The roof  310  is subsequently lowered onto the collapsed walls as illustrated in  FIG. 3   b . Containers may also have two, suitable more elongated, remaining side walls not shown in the Figures having a plane equal to the plane of  FIG. 3   a . It is preferred to first lower these two remaining side walls onto the base  304  and then pivot side walls  308 ,  306  towards the base  304  as explained above. In such a situation it is clear that side walls  308 ,  306  rest on the collapsed remaining side walls. An example of how the container of  FIG. 3   a  having two remaining side walls may be collapsed into the position illustrated in  FIG. 3   b  is described in NL-A-1017159. 
     The flexible connecting members are formed from any appropriate material including for example metallic chain, a synthetic rope or a strap or webbing material. In use, the roof  310  is lifted from the walls  306 ,  308  to allow the walls to be pivoted about the hinges  312 ,  314  and the roof is then lowered onto the collapsed walls as illustrated in  FIG. 3   b . It will be appreciated that with the flexible connecting members  316 ,  318 , the excessive clearance of the prior art design is not required, as the flexible connecting members  316 ,  318  can bend and fold around the pivoting walls  306 ,  308 . It is therefore only necessary to lift the roof  310  slightly in order to release the walls  306 ,  308  to pivot, rather than allowing for the large pivoting movement of the rigid connection members of the prior art. It is a further advantage that, in the assembled condition, the flexible connecting members  316 ,  318  may bend to be accommodated within the available space, and need not interfere with proper sealing between the walls  306 ,  308  and roof. The container  302  may therefore be made watertight. 
     With reference to  FIGS. 4   a  and  4   b , another embodiment of collapsible container  402  comprises a base  404 , opposed side walls  406 ,  408  and a roof  410 . The walls  406 ,  408  are hinged to the base  404  at hinges  412 ,  414  such that they may rotate about the hinges and fold onto the base  404 . The hinges  412 ,  414  thus define axes of rotation for the walls  406 ,  408 , these axes of rotation being substantially adjacent to the base  404 . As in the embodiment of  FIG. 3 , the walls  406 ,  408  may have a simple linear cross section or may have an L shaped cross section as shown in the Figures. The roof  410  is connected to the opposed side walls  406 ,  408  via flexible connecting members  416 ,  418 . The flexible connecting members are formed from any appropriate material including for example metallic chain, a synthetic rope or a strap or webbing material. Each connecting member  416 ,  418  comprises a first end which is connected via a first hinge  424 ,  426  to a respective side wall  406 ,  408 . The second ends of the connection members  416 ,  418  are connected to carriages  438 ,  440  adapted to be slidably received within a respective slot or channel  434 ,  436  formed on the roof  410 . The carriages  438 ,  440  may be of any appropriate form suitable for sliding engagement with a slot or rail. For example, the carriages may be received within the corresponding slot or channel, or may comprise a bifurcated formation and may be configured to extend either side of a protruding rail. Similarly, the slots, rails or channels  434 ,  436  may be of any suitable form. For example, appropriate slots or channels may be formed in the material of the roof  410 , or rails may be affixed to the roof  410  for engagement with the carriages  438 ,  440 . According to one embodiment, biasing springs  442 ,  444  may be housed within or adjacent the rails  434 ,  436  to bias the carriages  438 ,  440  to a neutral or stowed position. The stowed position is a position towards a central region of the respective rail  434 ,  436 . The biasing springs  442 ,  444  have the desirable effect of ensuring that the flexible connecting members do not hang too far inside the container in either the assembled or the collapsed condition. It will be appreciated that it is desirable for the flexible connecting members  416 ,  418  to be held along the roof  410  and out of the way of the container components or contents as much as possible. By biasing the carriages  438 ,  440  to a neutral position in the centre of the rails  434 ,  436 , it is ensured that the flexible connecting members  416 ,  418  do not hang slack in either the assembled condition (for example should the carriages  438 ,  440  be at the outer extent of the rails  434 ,  436 ) or in the collapsed condition (for example should the carriages  438 ,  440  be at the inner extent of the rails,  434 ,  436 ). The biasing springs  442 ,  444  may thus operate in both compression and extension to ensure the carriages  438 ,  440  remain towards a neutral position when at rest, regardless of the state of assembly of the container  402 . 
     The flexible connecting members  416 ,  418  allow for considerable misalignment between the roof  410  and the rest of the container  402  without causing undesirable stresses in the connecting members  416 ,  418  or their connections to the walls  406 ,  408  or roof  410 . Jamming of the sliding joints is also avoided. The container  402  is thus simpler to assemble and disassemble than those of the prior art, as it does not require accurate alignment of the roof  410  during assembly or disassembly. In addition, the hinges or other connections between the connecting members  416 ,  418  and the walls  406 ,  408  and roof  410  may be made less robust, as they do not need to withstand large jamming forces. 
     With reference to  FIGS. 5   a  and  5   b , another embodiment of collapsible container  502  comprises a base  504 , side walls  506 ,  508  and a roof  510 . The walls  506 ,  508  are hinged to the base  504  at hinges  512 ,  514  such that they may rotate about the hinges and fold onto the base  504 . The hinges  512 ,  514  thus define axes of rotation for the walls  506 ,  508 , these axes of rotation being substantially adjacent to the base  304 . As in the embodiment of  FIG. 3 , the walls  506 ,  508  may have a simple linear cross section or may have an L shaped cross section as shown in the Figures. The roof  510  is connected to the opposed side walls  506 ,  508  via partially flexible connecting members  516 ,  518 , each of which is connected via a first hinge  524 ,  526  to a respective side wall  506 ,  508  and via a second hinge  520 ,  522  to the roof  510 . The partially flexible connecting members are formed from a rigid portion  550  and a flexible portion  552 . The rigid portion comprises a rod  550 , which may be hollow, and the flexible portion comprises a chain, rope or strap  552 . The rigid and flexible portions  550 ,  552  of the connecting members  516 ,  518  may be fixedly or slidingly connected, as described in further detail below with reference to  FIGS. 7 and 8 . The rigid portions  550  are connected at the second hinges  520 ,  522  to the roof  510  and the flexible portions  552  are connected at the first hinges  524 ,  526  to the walls  506 ,  508 , allowing the flexible portions  552  to fold and wrap around the walls during disassembly. 
     The partially flexible connecting members  516 ,  518  offer a combination of advantages owing to the combination of flexible and rigid behaviour. The flexible part  552  of the connecting members  516 ,  518  folds and bends, allowing for misalignment of the roof  510  during assembly and disassembly without causing strain on the connections with the walls  506 ,  508  and roof  510 . In addition, excess clearance around the connecting members  516 ,  518  is not required, meaning the roof  510  can be correctly sealed to the walls  506 ,  508  in the assembled condition. The rigid part  550  of the connecting members helps to ensure that the connecting members do not hang down inside the container  502  in the assembled condition. 
     The partially flexible connecting members can also be employed in an embodiment of container having a sliding connection between the connecting members and the roof, as illustrated in  FIGS. 6   a  and  6   b . The container  602  of  FIGS. 6   a  and  6   b  comprises a base  604 , opposed side walls  606 ,  608  and a roof  610 . The walls  606 ,  608  are hinged to the base  604  at hinges  612 ,  614  such that they may rotate about the hinges and fold onto the base  604 . The hinges  612 ,  614  thus define axes of rotation for the walls  606 ,  608 , these axes of rotation being substantially adjacent to the base  604 . As in the embodiment of  FIG. 3 , the walls  606 ,  608  may have a simple linear cross section or may have an L shaped cross section as shown in the Figures. The roof  610  is connected to the opposed side walls  606 ,  608  via partially flexible connecting members  616 ,  618 . The partially flexible connecting members  616 ,  618  comprise a rigid portion  650 , which may be a hollow rod, and a flexible portion  652 , which may be a chain, rope or strap. The rigid and flexible portions  650 ,  652  of the connecting members  616 ,  618  may be fixedly or slidingly connected, as described in further detail below with reference to  FIGS. 7 and 8 . A free end of the flexible portion  652  of each connecting member  616 ,  618  is connected via a first hinge  624 ,  626  to a respective side wall  606 ,  608 . A free end of the rigid portion  650  of each connecting member  616 ,  618  is connected to a carriage  638 ,  640  adapted to be slidably received within a respective slot or channel  634 ,  636  formed on the roof  610 . As in the embodiment of  FIGS. 4   a  and  4   b  described above, the carriages  638 ,  640  may be of any appropriate form suitable for sliding engagement with a slot or rail. For example, the carriages may be received within the corresponding slot or channel, or may comprise a bifurcated formation and may be configured to extend either side of a protruding rail. Similarly, the slots, rails or channels  634 ,  636  may be of any suitable form. For example, appropriate slots or channels may be formed in the material of the roof  610 , or rails may be affixed to the roof  610  for engagement with the carriages  638 ,  640 . 
     Biasing may be included in the embodiment of  FIG. 6 , in order to ensure that the flexible portions  652  of the connecting members  616 ,  618  do not hang down inside the container  602 . Biasing springs (not shown), of the type described above with respect to  FIGS. 4   a  and  4   b , may be incorporated within the rails  634 ,  636 . Alternatively, the biasing may be incorporated into the connection members themselves, as illustrated in  FIG. 8  and described below. 
       FIGS. 7 and 8  illustrate two embodiments of a partially flexible connecting member  716 , which are suitable for use with any of the above described embodiments of collapsible container. 
     With reference to  FIG. 7 , a first embodiment of connecting member  716  comprises a hollow rigid rod  750  terminating at a first end in a connection  780  for engagement with a roof of a collapsible container. The connection  780  may comprise part of a hinged connection, a pin, an integrally formed carriage or any other appropriate connection. The hollow rod  750  is preferably formed from a robust metallic material such as steel. The connecting member  716  further comprises a flexible portion  752  formed from a rope, chain, strap or similar robust but flexible material. A first end of the flexible portion  752  terminates in a connection  782  for engagement with a wall of a collapsible container. As with connection  780 , the connection  782  may comprise part of a hinged connection, a pin, or any other appropriate connection. The rigid and flexible portions  750 ,  752  are fixedly joined together by a connector  770  which engages an annular flange  754  on the second end of the rod  750  and through which the second end of the flexible portion  752  passes. The second end of the flexible portion is secured to the connector  770  by a nut, clamp or other connection mechanism having sufficient integrity to withstand the predicted in service loads. 
     With reference to  FIG. 8 , the connector  770  may be replaced with a sliding connection arrangement, such that the combined length of the connection member  716  may be varied, and may biased towards a certain length. According to this arrangement, the second end of the flexible portion  752  extends into the hollow rigid rod  750  and terminates an at engagement plate  756 . A biasing spring  784  is mounted within the hollow rigid rod  750  about the flexible portion  752 . The biasing spring engages at a first end upon the engagement plate  756  of the flexible portion  752  and engages at a second end on the annular flange  754  of the hollow rigid rod. The flexible portion  752  of the connecting member is thus biased to retract into the hollow rigid rod, ensuring that excess length of the flexible connecting member will not hang slack when it is not required and will be neatly stored away within the hollow rigid rod, where it cannot catch or tangle with any components or contents of the container with which it is used. 
     The present invention thus provides a collapsible container affording several advantages over known containers. The connections between the connecting members and the walls and roof of the container may be made simpler and less robust, as they do not need to withstand such large forces during assembly and disassembly. A large clearance around the connecting members is not required, allowing for reliable sealing between the roof and walls, and misalignment of the roof during assembly or disassembly can be accommodated without unduly stressing any of the container components.