Abstract:
The present invention discloses a novel apparatus and way to aid in the folding of a shipping container. One or more spring assemblies are provided to control the load applied during the folding process by applying a torque to a series of torsion springs and bar extending along at least a portion of the length of the container sidewall.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 62/281,823 filed on Jan. 22, 2016. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to a shipping container. More specifically the present invention relates to a system and method for folding and unfolding walls of a shipping container. 
       BACKGROUND OF THE INVENTION 
       [0003]    The shipping industry uses large cargo containers to ship cargo from one location to another in domestic and global commerce. Such containers are designed to be conveniently moved from one mode of transport to another across the land by road or on rail or over the sea. Such containers are sometimes referred to as “intermodal shipping containers” or “freight containers.” The use of such containers has essentially eliminated the need for manually transferring cargo from one vessel to another, or from one vehicle or railcar to another in the effort to deliver the cargo to its final destination. 
         [0004]    Today, cargo containers are generally standardized by internationally recognized standards, and by national domestic standards with respect to dimensions and structure. Thus, the standard containers can be securely arranged in vertical stacks in side-by-side and end-to-end relationship with each other, and can be handled most effectively when transferring from one mode of transport to another regardless of their source or destination. 
         [0005]    Often, these containers must be transported empty from one delivery point to the next location where cargo is available for shipment. Transport of empty containers costs the shipper money and erodes profits since transport of each such container incurs handling cost and occupies valuable space which could otherwise be used to ship a revenue producing container loaded with cargo. Additionally, the shipping of both loaded and empty containers creates problems such as how to arrange the lighter, empty containers and the heavier, loaded containers aboard ships in such a manner that the safety of the ships is not compromised. Beyond safety issues, the shipment of empty containers causes monetary losses for shippers, losses which result in either substantial financial impact on the shipper or increased charges to customers for the handling and transport of loaded containers. Similar cost disadvantages apply when shipping empty containers over road or by rail. 
         [0006]    Long ago shippers recognized that significant economic savings in shipping could be realized if empty containers could be “folded” so as to occupy a substantially smaller space, so that less space need be sacrificed in the transporting of empty containers. Such an effort presently exists only for the “open frame” or flat rack type containers. To that end, the prior art proposed many foldable or nesting cargo containers of the enclosed types intended to reduce the space required for their shipment when empty. While such prior art foldable containers have been proposed, the market has not embraced the prior art containers as a substitute for the standard, non-foldable cargo containers due to these prior art foldable containers not meeting ISO standards and ISO certifications for being water proof. 
         [0007]    A shortcoming of foldable containers of the prior art is the lack of structural designs which enable or facilitate the folding and un-folding of such containers in a simple and effective manner with commonly available equipment. More specifically, foldable containers of the prior art do not provide an easy and controllable way of folding and unfolding the walls of the container. The walls of the these types of large intermodal shipping containers are typically fabricated from corrugated steel and for a standard 40 High Cube container, these walls can weigh upwards of 1500 pounds, thus making their raising and lowering extremely difficult and dangerous. 
         [0008]    Prior collapsible containers have walls which include lifting mechanisms to aid in the raising of the container walls. One such example is a lifting bar, such as that disclosed in U.S. Pat. No. 9,022,242 assigned to Holland Container Innovations, and depicted generally in  FIGS. 1 and 2 . In this configuration, lever arm  8  extends at a ninety degree angle relative to wall  2  and is connected to wall  2  by connecting member  10 . The lever arm  8  provides a point a distance away from the wall  2  where a manual force can be applied to create a moment to help raise the wall  2 , causing it to pivot about hinge  4 . While this mechanism provides a way of lifting the sidewalls through a lever type arrangement, this device requires a large amount of force applied to the lifting bars to overcome the weight of the container sidewalls. However, such a configuration also has disadvantages including the labor and force required to erect the container. 
       SUMMARY 
       [0009]    The present invention discloses systems and methods for folding and erecting a shipping container. More specifically, in an embodiment of the present invention, a spring assembly is provided for use in supporting the folding of the sidewalls of a collapsible container. The spring assembly comprises a bar extending a length along the sidewall with the bar being oriented parallel to an axis of rotation for the sidewall. The spring assembly also comprises a plurality of torsion springs arranged about the bar with each spring having a first end generally parallel to the bar and a second end generally perpendicular to the bar. The first end of the spring, which is parallel to the bar and rigidly connected to the bar by the washer, transmits the torque of the spring through the rod, into the hinge and then into the sidewall. The second end of the spring, or perpendicular end, is restricted by the base beam or external cover allowing the rotation of the sidewall to rotate the spring and store the torque generated. 
         [0010]    In an alternate embodiment of the present invention, a collapsible container is provided comprising a base panel, a roof panel spaced a distance from the base panel and generally parallel to the base panel, and a pair of sidewalls extending between the base panel and the roof panel, where the sidewalls are rotatably coupled to the base panel along a bottom edge of the sidewalls. The container also has a door panel and front panel extending between the pair of sidewalls, with the door panel and the front panel being rotatably coupled to the roof panel. One or more spring assemblies is positioned near the bottom edge of each sidewall and in contact with the sidewalls, where the spring assembly comprises a bar extending a length along the sidewall and a plurality of torsion springs coupled to the bar. Upon a folding of the sidewalls of the container, the sidewalls rotate to be generally parallel to the base panel, and in doing so, contact the plurality of torsion springs, causing the springs to twist and store energy produced by the sidewall rotation. 
         [0011]    The present invention also provides a method of folding a collapsible container in accordance with the associated systems discussed herein. Accordingly, the present invention also extends to a method of erecting a shipping container from its folded condition. 
         [0012]    It is an object of the present invention is to provide a novel, foldable, enclosed shipping container where the shipping container is folded utilizing a torsional spring system along at least a portion of the container sidewalls. The weight of the sidewalls is used to the advantage of the folding and unfolding processes by increasing the tension in the springs during the folding process, such that upon erecting the container, tension in the springs is used to help raise the container sidewalls. 
         [0013]    In an embodiment of the present invention, a locking mechanism is provided for use with the spring assembly in order to provide a way of securing the container sidewalls when in a collapsed configuration. The locking mechanism comprises an adjustable strap that attaches to a top edge of the container sidewall and can also retract into a stored position when not in use. 
         [0014]    Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The instant invention will now be described with particular reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0015]    The present invention is described in detail below with reference to the attached drawing figures, wherein: 
           [0016]      FIG. 1  is a cross section view of a portion of a container of the prior art. 
           [0017]      FIG. 2  is a cross section view of a container of the prior art. 
           [0018]      FIG. 3  is a perspective view of a collapsible container in accordance with an embodiment of the present invention. 
           [0019]      FIG. 4  is a perspective view of the container of  FIG. 3  in a collapsed, or folded, condition. 
           [0020]      FIG. 5  is perspective view of the collapsible container of  FIG. 3 , including a spring assembly in accordance with the present invention. 
           [0021]      FIG. 6  is a partial perspective view of a portion of the collapsible container of  FIG. 5  in accordance with an embodiment of the present invention. 
           [0022]      FIG. 7  is a perspective view of the collapsible container of  FIG. 5  depicting a sidewall folding inward in accordance with an embodiment of the present invention. 
           [0023]      FIG. 8  is a partial perspective view of a portion of the collapsible container of  FIG. 5  depicting a sidewall folding inward in accordance with an embodiment of the present invention. 
           [0024]      FIG. 9  is a perspective view of an alternate embodiment of the present invention. 
           [0025]      FIG. 10  is a perspective view of the collapsible container of  FIG. 9  depicting a sidewall folding inward. 
           [0026]      FIG. 11  is a detailed perspective view of a portion of the collapsible container of  FIG. 9 . 
           [0027]      FIG. 12  is a detailed perspective view of a portion of the collapsible container of  FIG. 10  depicting a sidewall folding inward. 
           [0028]      FIG. 13  is an elevation view of a spring assembly in accordance with an embodiment of the present invention. 
           [0029]      FIG. 14  is a perspective view of the spring assembly and gear mechanism of  FIG. 13 . 
           [0030]      FIG. 15  is an alternate elevation view of the spring assembly in accordance with an embodiment of the present invention. 
           [0031]      FIG. 16  is a cross section view through the gear mechanism of a collapsible container in accordance with an embodiment of the present invention. 
           [0032]      FIG. 17  is a partial cross section view of a collapsed container and locking mechanism when not in use. 
           [0033]      FIG. 18  is a partial cross section view of a collapsed container depicting a locking mechanism for securing a sidewall in a collapsed configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    The present invention discloses a system and method for improving the foldable nature of a shipping container. More specifically, embodiments of the present invention relate to systems and methods for improving the way in which the walls of the container are folded or erected. A discussion of the present invention follows and relates to  FIGS. 3-16 . 
         [0035]    Referring now to  FIG. 3 , a collapsible container  100  in accordance with an embodiment of the present invention is shown in its upright, erect, configuration while  FIG. 4  shows the container  100  in its collapsed state. The container  100  comprises a base panel  102 , a roof panel  104  spaced a distance from the base panel  102 , with the roof panel  104  generally parallel to the base panel  102 . A pair of opposing and parallel sidewalls  106  extends between the base panel  102  and roof panel  104  where the sidewalls  106  are rotatably coupled to the base panel  102  along a bottom edge  108  of the sidewalls  106 . The container  100  also includes a door panel  110  and front panel  112  that extend between the sidewalls  106 . However, the door panel  110  and front panel  112  are rotatably coupled to the roof panel  104 . 
         [0036]    The collapsible container  100  also comprises a spring assembly  120 , as depicted in  FIGS. 5-18 . The spring assembly  120  in turn can comprise a primary spring assembly, arranged in a single axis as shown in  FIGS. 5-8  or a primary and secondary spring assembly arrangement as shown in  FIGS. 9-15 , depending on the container configuration. The spring assembly  120  is positioned proximate the bottom edge  108  of the sidewalls  106 . The spring assembly  120  operates in conjunction with the plurality of hinges  122  as shown in  FIGS. 6, 8 , and  11 - 15 . The hinges  122  connect the sidewall  106  to the base panel  102 . As depicted herein, the spring assembly  120  can be positioned in the same axis as that about which the hinges  122  rotate. Alternatively, the spring assembly  120  (primary and/or secondary) can have one or both assemblies located along an axis that is parallel to the hinges  122 . 
         [0037]    One or more bars  124  extend along at least a portion of the sidewall  106  and a plurality of torsion springs  126  are coupled to the one or more bars  124  as shown in  FIGS. 12, 13 and 15 . In the configuration depicted in  FIGS. 5 and 9 , the bar  124  extends the length of the sidewall  106  and is rigidly secured to the hinges  122 . In an alternate embodiment, the bar  124  is comprised of multiple bars that positioned end to end and together extend approximately the length of the sidewall  106 . More specifically, and with reference to  FIGS. 11-15 , the torsion springs  126  are connected to the bar  124  by way of a washer  128  (see  FIG. 15 ) where the washer  128  is rigidly secured to the bar  124 , by a means such as welding. Referring to  FIG. 15 , the torsion springs  126  have a first end  126 A that is oriented parallel to the bar  124  and is captured by the bar  124  as the first end  126 A slides into a receiving hole (not shown) in the washer  128 . The torsion springs  126  also have a second end  126 B that is generally perpendicular to the bar  124 . For the second end  126 B, this end can face one of two ways, either upwards or downwards from the bar  124 . As shown in  FIG. 15 , this orientation alternates in order to counteract the reaction forces that the springs  126  exert on the bar  124 . 
         [0038]    The second portion of the torsion spring  126 B is in contact with a portion of the sidewall  106  such that upon a lowering, or folding, of the sidewalls  106  in towards the base panel  102 , the sidewalls  106  rotate to be generally parallel to the base panel  102 . As a result, the sidewalls  106  apply a force to the second portion  126 B of the torsion springs, causing the torsion springs  126  to twist and impart a force to the bar  124 . The torsion springs  126  and bar  124  absorbs the force applied thereto as the sidewalls  106  are folded in towards the base panel  102 . The energy imparted in the springs  126  and bar  124  can then be utilized to assist in raising the sidewalls  106  from the folded position. 
         [0039]    Typically, a secondary spring assembly is implemented when the moment torque required for the sidewall  106  is greater than what the primary torsion spring torque can produce. When a secondary spring assembly is utilized, as shown in  FIGS. 9-15 , a second bar  130  and plurality of torsion springs  132  are arranged parallel to the bar  124  and torsion springs  126 . The second bar  130  and torsion springs  132  operate in the same way as the bar  124  and torsion springs  126 . In this configuration the parallel rows of spring assemblies are coupled together through a gear mechanism  140  as shown in  FIGS. 11-16 . The secondary spring assembly is connected via a set of three gears  140 A,  140 B, and  140 C which translates the rotation of the sidewall  106  from the main spring assembly to the secondary spring assembly, as shown in  FIGS. 14 and 16 . The gear mechanism  140  translates the load from one assembly to the other so they act in parallel. This system provides the additional torque needed at the lower 45 degrees of rotation where the first spring assembly can struggle. The present invention is not limited to two spring assemblies coupled together by a single gear mechanism. It is possible that multiple rows of spring assemblies can be utilized, requiring multiple gear mechanisms. 
         [0040]    As depicted in  FIGS. 11-15 , the second bar  130  and torsion springs  132  of the secondary spring assembly do not extend the entire length of the sidewall  106  and are located towards the ends of the sidewall  106 . This arrangement is but one acceptable configuration for the secondary spring assembly. Alternate arrangements may include the secondary spring assembly extending the length of sidewalls  106  or an alternate length. In this embodiment, the secondary spring assembly is located beneath the primary spring assembly and is coupled to the primary spring assembly (bar  124  and springs  126 ) by the gear mechanism  140  as shown in  FIGS. 11-16 . The exact size, length, and quantity of springs  132  required as part of the secondary spring assembly will depend on factors such as the container size, weight of the sidewalls, etc. Presently, the second bar  130  and springs  132  are located at each end of the sidewall  106  primarily because the ends of the sidewalls  106  are slightly heavier than the middle portion of the sidewalls  106 . The present invention is not limited to the configuration depicted herein, and depending on a variety of design factors, may also include additional spring assemblies. 
         [0041]    In an embodiment of the present invention, an adjustability function is provided for the torsional springs  126  and  132 . That is, the springs can be pre-torqued from one to thirty degrees, which allows for an operator of the collapsible container to reach the required torque necessary to open the sidewall  106  from the collapsed position. The amount of torque required varies depending on the final weight of the sidewall. Due to manufacturing tolerances the overall weight of the sidewall can vary by up to 75 pounds, which changes the moment of the panel, which in turn, correlates to the torque required. Pre-torquing the springs  126  and  132  also provides a safety measure when the folding process is first initiated by helping to prevent the sidewall  106  from falling prematurely when it is no longer connected to the roof panel  104  or the door or front panels  110  or  112 . The torsion springs  126  and  132  are adjustable by this pre-torquing, which occurs at the original assembly of the collapsible container. Alternatively, the torsion springs  126  and  132  are also adjustable after the initial container assembly through an external set screw, which acts on the vertical leg of the spring through the base beam so as to change the pre-torque angle. Also, the springs  126  and  132  can be aligned at a desired angular position to achieve a desired amount of torque so as to be pre-torqued or slack when the sidewall  106  is in a vertical position. 
         [0042]    Referring back to  FIGS. 11-15 , the springs  126  and  132  are spaced generally evenly along the respective bars  124  and  130  and equidistant between the hinges  122 . Such a spacing allows for equal distribution of the force applied by the sidewalls  106  onto the torsion springs. 
         [0043]    The torsion springs  126  and  132  are sized to be coaxial with the bar  124  and  130 , as shown in  FIGS. 7 and 8 . Each of the springs  126  and  132  have between six and twelve active coils and a spring rate ranging from 6 lbf.-in./deg. to 11.75 lbf.-in./deg. 
         [0044]    The present invention also incorporates friction reduction technology in order to facilitate torsion spring effectiveness in the folding of the sidewalls  106 . For example, Teflon® bushings can be placed between the bar  124 / 130  and the receiving position of the base beam where the bar  124 / 130  rotates to reduce the friction interface at this point of rotation. 
         [0045]    Another feature of the present invention is a locking mechanism  150  which is used for securing the sidewalls  106  in place when the container is in a folded position. Referring to  FIGS. 17 and 18 , the container  100  includes one or more locking mechanisms  150 , each having a strap  152  that captures a rigid pin  154 , which is located along a top portion of the sidewall  106 . The strap  152  recesses into the base panel  102  when not in use, as shown in  FIG. 17 . Once the sidewall  106  is collapsed, the strap  152  is pulled out from its recess and connected to the pin  154  on the top of sidewall  106 . The resistance of the sidewall  106  keeps the strap  152  taught when it is extended to secure the sidewall. The strap  152  is preferably fabricated from a nylon or other durable and flexible material in order to withstand the environmental and operating conditions. 
         [0046]    As used herein, the term “panel” can comprise a single section or in the alternative can be comprised of multiple sections secured together by an acceptable process, such as welded together to form a weldment. 
         [0047]    The foldable container  100  of the present invention is folded in a way such that it is capable of being stacked vertically multiple units high when not in use. The container geometry described herein permits the stacking of the containers as described in co-pending U.S. patent application Ser. No. 14/829,275. 
         [0048]    The foldable container  100  of the present invention is fabricated from materials capable of withstanding a variety of weather elements and operating conditions. At least the exterior surfaces of the roof panel  104 , base panel  102 , front panel  112 , door panel  110 , and sidewalls  106  are fabricated from corrugated metal, such as CorTen® steel. For example, CorTen® A, also known as A588, is an industry standard acceptable material as this material provides excellent corrosion resistance. This material capability is necessary given the harsh weather conditions experienced by the foldable container, including but not limited to salt water, sea air, rain, snow, and extreme heat and cold. Internal walls of the foldable container  100  can be corrugated metal or can be lined with other materials as desired by the owner/operator of the foldable container  100 . Such container material provides the necessary protection of the internal spring assembly components whether the container is in its erect or folded state. 
         [0049]    The materials of the spring assembly are typically higher strength steels. For example, the bar may be made from 1144 while the washer may be made from higher strength steel such as ASTM A514. 
         [0050]    The present invention is applicable to a variety of standard intermodal shipping containers. For example, the folding container and associated spring assembly technology can be configured to accommodate various container lengths as used in the intermodal transport industry including, but not limited to, containers of 10 feet, 20 feet, 24 feet, 40 feet, 48 feet, and 53 feet in length. 
         [0051]    While the invention has been described in what is known as presently the preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment but, on the contrary, is intended to cover various modifications and equivalent arrangements within the scope of the following claims. The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. 
         [0052]    From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims.