Abstract:
Stackable trailers, kits, and components for stackable trailers are disclosed. The kits and components provide added functionality to existing or newly manufactured trailers for carrying shipping containers of various sizes. Stackability, modularity, and cost savings can be achieved using the various disclosed components with trailers. Components include outriggers for receiving shipping containers, cradles for receiving trailer wheels, and assemblies for receiving trailer landing gears.

Description:
RELATED APPLICATIONS 
       [0001]    The present application is a continuation-in-part of U.S. patent application Ser. No. 12/104,045, filed Apr. 16, 2008, and claims the benefit of that application and incorporates that application by reference for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    The present subject matter relates generally to trailers that can be pulled by tractors, and more particularly to kits and components for improving functionality of trailers and trailers incorporating such kits and components, whereby the trailers can transport storage containers and/or be stacked when not in use. 
       BACKGROUND 
       [0003]    In recent years a substantial amount of cargo is transported by ships in containers. Some large ships cans carry thousands of containers. 
         [0004]    After these containers are unloaded at a port, they are transported on trailers pulled by a tractor. A large number of there containers are twenty and forty feet long normally requiring trailers of different lengths. 
         [0005]    It has become a problem as shipping increases to store the trailers prior to the ships being unloaded. Space at the ports for storing the trailers is limited since most of ports are located in large cities close to the sea. 
         [0006]    Moreover forty foot trailers are not always suitable for transporting twenty foot containers since the load on the trailers would not be balance lengthwise on the trailer. An unbalanced trailer could overload one of the sets of wheels on the tractor trailer. When a trailer is not balanced properly, such increases the damage on the highways that they travel. 
         [0007]    The containers that the trailers are provided to transport are normally used to transport freight over land by rail or by ships. The containers are adapted to be mounted on railroad double-stack or flat cars, highway truck trailer chassis&#39;s and stored in stacks on ships. 
         [0008]    Freight containers which are capable of being stacked in a superimposed relation are known in the prior art. Examples of such containers are disclosed by U.S. Pat. No. 3,044,656. 
         [0009]    Each corner of the container is provided with a corner post connected between associated pairs of upper and lower steel castings which comprise load bearing members of the containers. Conventional openings in each of the steel castings facilitate the interlocking of the containers with suitable lifting means for transferring the container from a land vehicle to a ship and vice versa, as well as to facilitate the positioning and securing together of containers in a stack relationship. U.S. Pat. No. 3,044,653 discloses in detail the method of coupling the containers together when they are being stacked and such is incorporated herein by reference. 
         [0010]    Replacing all of such trailers with stackable and/or multi-container capable trailers would be very expensive. 
       SUMMARY 
       [0011]    In accordance with certain aspects of the disclosure a kit is disclosed for adding functionality to a trailer for use with a tractor for transporting containers, the trailer including an elongated body, at least two wheels attached to a rear portion of the elongated body, and a landing gear attached to a front portion of the elongated body. The kit includes at least two wheel receiving assemblies attachable to the elongated body at a position corresponding to a location of the wheels, each wheel receiving assembly including a central body portion, a fixed upper hook attached to the central body portion, a movable lower hook attachable to the central body portion, and a wheel cradle attached to the central body portion, the wheel receiving assembly configured to be attachable to the elongated body by the upper hook, central body portion and lower hook. The trailer may have another like trailer stacked upon it by placing respective wheels of the like trailer on respective wheel cradles of the trailer. Various options and modifications are possible. 
         [0012]    For example, the kit may include four of the wheel receiving assemblies, or each of the at least two wheels of the trailer includes dual wheels, and the wheel cradles are configured to receive dual wheels. Also, the lower hooks may be separable from the central body portion and attachable via fastening members. If desired, a landing gear receiving assembly may be attachable to the landing gear, the landing gear receiving assembly including an extending body portion configured to be attachable to the landing gear, whereby the trailer may have another like trailer stacked upon it by placing the landing gear of the like trailer in the landing gear receiving assembly before stacking. 
         [0013]    The kit may also include at least two container mounting assemblies attachable to the elongated body at a position corresponding to a location of mounting structure of a container, each container mounting assembly including a central arm portion, a fixed upper hook attached to the central arm portion, a movable lower hook attachable to the central arm portion, and a container mounting structure attached to the central arm portion, the container mounting assembly configured to be attachable to the elongated body by the upper hook, central arm portion and lower hook. The trailer may have a container of a given size attached to it by connecting the respective mounting structure of the container with respective container mounting structure of the container mounting assemblies. If desired, kit may include four of the container mounting assemblies. The container mounting assemblies may be configured and mounted to the trailer at respective locations so as to correspond to the size of a shipping container, whereby equipment used to lift a shipping container may also be used to lift the trailer via the container mounting assemblies. The container mounting structures may be configured to receive twist locks, and their lower hooks may be separable from the central arm portions and attachable by fastening members. Their central arm portions may be configured to extend non-orthogonally with respect to the elongated body. 
         [0014]    According to other aspects of the disclosure a kit is disclosed for adding functionality to a trailer for use with a tractor for transporting containers, the trailer including an elongated body, at least two wheels attached to a rear portion of the elongated body, and a landing gear attached to a front portion of the elongated body. The kit includes a number of wheel receiving assemblies corresponding to the number of wheels on the trailer, each wheel receiving assembly being attachable to the elongated body at a position corresponding to a location of a respective one of the wheels, each wheel receiving assembly including a central body portion, a fixed upper hook attached to the central body portion, a movable lower hook attachable to the central body portion, and a wheel cradle attached to the central body portion, the wheel receiving assembly configured to be attachable to the elongated body by the upper hook, central body portion and lower hook. A landing gear receiving assembly is attachable to the landing gear, the landing gear receiving assembly including an extending body portion configured to be attachable to the landing gear, whereby the trailer may have another like trailer stacked upon it by placing the landing gear of the like trailer in the landing gear receiving assembly before stacking and by placing respective wheels of the like trailer on respective wheel cradles of the trailer. Four container mounting assemblies are attachable to the elongated body at respective positions corresponding to a location of mounting structure of a container, each container mounting assembly including a central arm portion, a fixed upper hook attached to the central arm portion, a movable lower hook attachable to the central arm portion, and a container mounting structure attached to the central arm portion, the container mounting assembly configured to be attachable to the elongated body by the upper hook, central arm portion and lower hook. The trailer may have a container of a given size attached to it by connecting the respective mounting structure of the container with respective container mounting structure of the container mounting assemblies, and the container mounting assemblies being configured and mounted to the trailer at respective locations so as to correspond to the size of a shipping container. Equipment used to lift a shipping container may also be used to lift the trailer via the container mounting assemblies. The scope of the disclosure includes a trailer in combination with this and other kits, and various options and modifications are possible. 
         [0015]    According to other aspects of the disclosure, a kit is disclosed for adding functionality to a trailer for use with a tractor for transporting containers, the trailer including an elongated body, at least two wheels attached to a rear portion of the elongated body, and a landing gear attached to a front portion of the elongated body. The kit includes four container mounting assemblies attachable to the elongated body at respective positions corresponding to a location of mounting structure of a container, each container mounting assembly including a central arm portion, a fixed upper hook attached to the central arm portion, a movable lower hook attachable to the central arm portion, and a container mounting structure attached to the central arm portion, the container mounting assembly configured to be attachable to the elongated body by the upper hook, central arm portion and lower hook, whereby the trailer may have a container of a given size attached to it by connecting the respective mounting structure of the container with respective container mounting structure of the container mounting assemblies, the container mounting assemblies being configured and mounted to the trailer at respective locations so as to correspond to the size of a shipping container. Equipment used to lift a shipping container may also be used to lift the trailer via the container mounting assemblies. As above, various options and modifications are possible. 
         [0016]    According to other aspects of the disclosure, a wheel receiving assembly is disclosed for attachment to a trailer to assist in stacking multiple of such trailers, each trailer including an elongated body including a beam. The wheel receiving assembly includes a central body portion, a fixed upper hook attached to the central body portion, a movable lower hook attachable to the central body portion, and a wheel cradle attached to the central body portion, the wheel receiving assembly configured to be attachable to the elongated body by placing the upper hook over the beam, the central body portion against the beam, and the lower hook under the beam, with the lower hook attached to the central portion, whereby the trailer may have another like trailer stacked upon it by placing respective wheels of the like trailer on respective wheel cradles of the trailer. Again, various options and modifications are possible. For example, the wheel cradle may be configured with an indentation on at least one side thereof for positioning the wheel receiving assembly on the beam at a given spot aligned with a tire of the trailer while avoiding structure of the trailer. 
         [0017]    According to other aspects of the disclosure, a container mounting assembly is disclosed for attachment to a trailer for use with a tractor for transporting containers, the trailer including an elongated body including a beam. The container mounting assembly includes a central arm portion, a fixed upper hook attached to the central arm portion, a movable lower hook attachable to the central arm portion, and a container mounting structure attached to the central arm portion, the container mounting assembly configured to be attachable to the elongated body by placing the upper hook over the beam, the central arm portion against the beam, and the lower hook under the beam, with the lower hook attached to the central portion, whereby the trailer may have a container of a given size attached to it by connecting the respective mounting structure of the container with respective container mounting structure of the container mounting assembly, the container mounting assemblies being configured and mounted to the trailer at respective locations so as to correspond to the size of a shipping container. Equipment used to lift a shipping container may also be used to lift the trailer via the container mounting assemblies. Again, various options and modifications are possible. 
         [0018]    Particular embodiments of the trailers and stackable features of the trailers, the kits, and the components are described in greater detail below by reference to the examples in the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of an embodiment of a stackable trailer according to the invention showing trailers being stacked one upon the other. 
           [0020]      FIG. 2  is a perspective view illustrating the positioning bar of the trailer. 
           [0021]      FIG. 3  is a side-elevational view illustrating stacked trailers. 
           [0022]      FIG. 4  is partial side-elevational view illustrating the position of the landing gear of a trailer when one trailer is stacked on top of another trailer. 
           [0023]      FIG. 5  is a partial plan view illustrating the positioning bar on top of another trailer. 
           [0024]      FIG. 6  is a perspective view illustrating the positions of a 40 foot and 20 foot container on a trailer. 
           [0025]      FIG. 7  is a fragmentary perspective view illustrating the supporting arm for container connector receiver and a container connector prior to being inserting into the container connector receiver. 
           [0026]      FIG. 8  is a partial perspective view illustrating a container connector positioned to be inserted into a corner post of a container. 
           [0027]      FIG. 9  is a partial perspective view illustrating a container connector locking a container onto a lateral support arm. 
           [0028]      FIG. 10  is a side-elevational view illustrating the position of a 20 foot and 40 foot container when loaded on a trailer. 
           [0029]      FIG. 11  is a side-elevational view illustrating a crane in schematic form lifting a stackable container. 
           [0030]      FIG. 12  is a perspective view of one example of a cradle assembly according to certain aspects of the disclosure. 
           [0031]      FIG. 13  is a side view of the cradle assembly of  FIG. 12 , showing attachment to a beam. 
           [0032]      FIG. 14  is a front view of the cradle assembly of  FIG. 12 . 
           [0033]      FIG. 15  is a rear view of the cradle assembly of  FIG. 12 . 
           [0034]      FIG. 16  is a perspective view of another example of a cradle assembly according to certain aspects of the disclosure. 
           [0035]      FIG. 17  is a left side view of the cradle assembly of  FIG. 16 , showing attachment to a beam. 
           [0036]      FIG. 18  is a right side view of the cradle assembly of  FIG. 16 , showing attachment to a beam. 
           [0037]      FIG. 19  is a front view of the cradle assembly of  FIG. 16 . 
           [0038]      FIG. 20  is a rear view of the cradle assembly of  FIG. 16 . 
           [0039]      FIG. 21  is a top view of the cradle assembly of  FIG. 16 . 
           [0040]      FIG. 22  is a bottom view of the cradle assembly of  FIG. 16 . 
           [0041]      FIG. 23  is a perspective view of an example of a landing gear receiving assembly according to certain aspects of the disclosure. 
           [0042]      FIG. 24  is an end view of the landing gear receiving assembly of  FIG. 23 . 
           [0043]      FIG. 25  is a perspective view of an example of a container mounting assembly according to certain aspects of the disclosure. 
           [0044]      FIG. 26  is a right side view of the container mounting assembly of  FIG. 25 , showing attachment to a beam. 
           [0045]      FIG. 27  is a top view of the container mounting assembly of  FIG. 25 . 
           [0046]      FIG. 28  is a bottom view of the container mounting assembly of  FIG. 25 . 
           [0047]      FIG. 29  is a front view of the container mounting assembly of  FIG. 25 . 
           [0048]      FIG. 30  is a rear view of the container mounting assembly of  FIG. 25 . 
           [0049]      FIG. 31  is a schematic view of a trailer frame with a number of kit components attached to it. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0050]    Reference will now be made to embodiments of the invention, one or more examples of which are illustrated in the figures. The embodiments are provided by way of explanation of the invention, and are not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a further embodiment. It is intended that the present invention encompass these and other modifications and variations as come within the scope and spirit of the invention. 
         [0051]    Referring to  FIG. 1 , three trailers  10  stacked upon each other. Each of the stackable trailers includes an elongated body  12  that has a supporting surface  14  provided thereon upon which a container is positioned when being transported. There are two sets of wheels  16  and  18  carried adjacent the rear end of the elongated body  12  for supporting the rear of the trailer. A retractable landing gear  20  extends downwardly adjacent the front end of the trailer  10  for supporting the trailer on the ground and in the stacked position on top of another trailer. There are two pairs  22 ,  24  of wheel receivers positioned directly over the wheels  16 ,  18  of the trailer  10  but below the supporting surface  14  of the trailer. These wheel receivers  22 ,  24  are provided for receiving the wheels  16 ,  18  of a trailer that is stacked on top when the trailers are in a stacked configuration. 
         [0052]    A goose neck  26  is provided adjacent a front end of the elongated body  12  and includes an inclined surface  28  which terminates in a forwardly extending nose  30 . The trailer  10  as shown is a conventional goose neck trailer that is equipped with wheels and braking systems and a pin for fitting in a fifth wheel of tractor. The pin and tractor connection are not disclosed since it is well-known in the industry. Many aspects of the disclosure do not require a goose neck trailer though. 
         [0053]    The trailer  10  is constructed of laterally spaced I-beams  32 ,  34  which have suitable transverse metal bracing  36  extending therebetween. Positioned adjacent the front end of the trailer is a cross bar  38  that has a conventional locking pin  40  that is used for locking the front end of a container onto the trailer. The mechanism for manipulating the locking pin  40  is not disclosed since it is conventional on goose neck trailers that are constructed for carrying containers. Any suitable connector could be used for locking the front end of a 40 foot container on the trailer. 
         [0054]    Normally the trailer has eight wheels carried on the rear end thereof with two sets of four wheels  16 ,  18  provided on respective spaced axles. As shown in the drawings, there are four wheels on each side of the rear end of the trailer. 
         [0055]    Conventional twist locks  42  are carried on the rear end of the trailer and are mounted in a cross bar  44 . The twist locks  42  are provided with mechanical or electromechanically operated levers so as to rotate camming surfaces 90 degrees to lock the lower end of the containers onto the trailer. The upper end of the twist lock  42  fits within a hole provided on the corner posts  48  of the containers for locking the containers down onto the trailer. Any suitable conventional locking mechanism could be utilized for locking the containers onto the trailers. As shown, cross bars  38  and  44  are spaced to fit a 40 foot trailer. The cross bars could have other spacing for other container sizes, such as 20 foot, if desired. 
         [0056]    Each of the trailers is provided with a landing gear  20 . The landing gear  20  is equipped with a conventional mechanism for raising and lowering the landing gear in a telescoping manner. When the landing gear is lowered, the foot  50  of the landing gear rests on the ground for supporting the front end of the trailer. When the trailers are stacked the foot  50  rests on the next adjacent lower trailer. The foot  50  includes a positioning bar  52  that extends between the vertically extending telescoping posts  54 ,  56 . A connector plate  58  is pivotally connected by a pivot bolt  60  to the bottom of the vertically extending posts  56 ,  54 . Interposed between the connector plate  58  and the positioning bar  52  is an incline plate (sometimes called a sand shoe)  62 . If desired the landing gear may be placed on the ground using such plates  62 . Also, such plates  62  may include small wheels (not shown) on either side. In such case, pivot bolt  60  would also comprise an axle of such wheels). 
         [0057]    As shown, the incline plate  62  includes a forward angle portion  64  that extends upwardly at an angle of 55 degrees and an intermediate horizontal portion  66  which is attached between the connector plate  58  and the positioning bar  52 . One possible purpose of the inclined front portion  64  is to aid in positioning a trailer on top of another trailer when the trailers are being stacked. The inclined portion  64  would abut against the 55 degrees inclined surface  28  forming part of the goose neck of the lower trailer. The inclined plate  64  could be positioned on the bottom surface of the positioning bar  52  rather than between the connector plate  58  and the positioning bar  52 . 
         [0058]    The positioning bar  52  in one particular embodiment includes an elongated 2×10 board  68  which is sandwiched between metal plates  70 ,  72 . The metal plate  70  would rest on the asphalt when the trailer is on the ground. In one embodiment, the edges of the bottom plate  70  are beveled to prevent the plate  70  from digging into the asphalt surface when being supported thereon. When the inclined plate  64  is positioned on the bottom surface of the positioning bar  52  as a result of the front and rear sides being inclined upwardly they would not have the tendency to dig into the asphalt surface. 
         [0059]    Suitable conventional angle braces  74  extend from the vertically extending telescoping posts  54 ,  56  and the I-Beams  32  and  34  forming part of the trailer. A cross brace  76  is also positioned between the vertically extending posts  56 ,  54 . Additional bracing could be utilized if found necessary to strengthen the landing gear. 
         [0060]    The wheel receivers  22 ,  24  as shown in  FIGS. 3 and 6  through  9  are welded to the I-beams  32 ,  34  respectively, directly over the wheels  16 ,  18 . The wheel receivers  22  and  24  have a contoured surface  80  corresponding to the curvature of the tire of the trailer so that when a tire is supported in the wheel receiver it can nest therein. The contoured surface  80  is made out of metal and is welded to the I-beams  32 ,  34  as shown in  FIG. 6 . Suitable bracing  82  extends from the vertical portion  84  of the I-beam  32  as shown in  FIG. 7 . This bracing  82  provides a connection between the vertical flange of the I-beam and the lower portion of the wheel receivers  24  and  26  for supporting the wheel receiver on the I-beam. In U.S. Pat. No. 5,934,695, the wheel receivers  22  and  24  were removably attached to the I-beams, however, they could also be fixed by welding to the I-beam as shown in  FIG. 7 . In  FIGS. 7 and 8 , there is a flange  84  that extends up and over top of the I-beam  32  for aiding in supporting the wheel receivers  22 ,  24 . In some embodiments it may be desired to remove the flange  84  and only use bracing between the cradle  80  of the wheel receivers  22 ,  24  and the vertical extending flange of the I-beam. Such would permit the upper supporting surface of the I-beam  32  to be flat and smooth and enable the upper edge of the wheel receivers to be below the upper supporting flanges of the I-beams  32 ,  34 . 
         [0061]    Referring to  FIG. 6 , there is shown in dotted lines the position of a forty foot container  86  when it is mounted on the trailer for being transported. In order for the trailer to transport a 20 foot container  88  four sets of outwardly extending support arms  90  are supported on the I-beams  32 ,  34  and extend laterally outwardly therefrom. The outwardly extending support arms  90  are positioned on the I-beams  32 ,  34  as shown in  FIG. 6  so that the weight of a container  80  would be balanced between the front and rear of the trailer in order to minimize overloading of the rear wheels of the trailer or the rear wheels of the tractor pulling the trailer. A container connector receiver  96  is connected by welding or any other suitable means to the outward extending arms  92 ,  94 . This connector receiver  96  is in the form of a hollowed block which has an opening  98  provided in the top thereof so that a container connector such as a twist lock connector  100  can be inserted therein. The twist lock connector  100  has moveable flanges  102 ,  104  that can be rotated so that the lower flange  102  bears on the underside of the top surface  104  of the container connector receiver. The upper camming surface  104  is inserted through an opening provided in the lower end of a corner post of the container as shown in  FIG. 9  for locking the container down onto the supporting arms through the container connector receivers  96 . 
         [0062]    The twist locks  100  can be removed from the container connector receivers  96  when the trailer is being used for transporting a forty foot container. However, when a longshoreman is loading a twenty foot container  88  onto the trailer he first inserts the twist lock connector  100  into the opening  98  of the container connector receivers  96 . Once the container is positioned on the trailer with the upper cramming surface  104  extending into the corner post  80  of the container, the twist lock member is manipulated by a lever or a spring loaded plunger  103  to rotate the camming surfaces  102 ,  104  90 degrees for locking the container  88  onto the four laterally extending support arms. An access to the plunger  103  or a lever if used is provided through an opening  101  in an end wall of the container connector receiver  96  or an opening  105  in the side wall. The twist lock connectors  100  are conventional twist locks that are in use now for locking the rear end of containers on trailers and also for use when stacking containers one upon the other to lock a bottom of one container to the top of a container positioned therebelow. The twist lock connectors  100  extend into the corner posts of the containers for locking the containers in stacks by rotating the camming surfaces  102  and  104  90 degrees. 
         [0063]    As can be seen in  FIGS. 3 and 5  the container connector receivers  96  are laterally supported outwardly from the I-beams  32  and  34  on both sides of the trailer so that there are four container connector receivers  96  used for locking a twenty foot container onto the trailer. A first pair of container connector receivers  96  is positioned near the rear wheels of the trailer with a second pair of container connector receivers being located close to the landing gear. When a twenty foot container is transported on the trailer it presents a balanced load. A balanced load along the length of the trailer provides a smoother ride on the highway and minimizes damages to the highway as compared to when one set of wheels or the other is overloaded. It should be understood that various mounting locations are possible. 
         [0064]      FIG. 11  illustrates an overhead crane  110  lifting the trailers for stacking one upon the other. While the overhead crane  110  shown in  FIG. 11  is in a fixed position it is understood that the overhead crane could be mounted on wheels. When the overhead crane is mounted on wheels it enables the crane to move to where the trailers are being stacked or unstacked for moving them to a loading or unloading position. The crane  110  shown in  FIG. 11  lifts a trailer off the ground and moves it over another trailer so that it can be lowered on top of the second trailer with the rear wheels of the upper trailer nesting in the wheel receivers  22  and  24  of the lower trailer. The inclined plates  62  carried by the positioning bar may nest against the incline surface  28  of the goose neck of the lower trailer, if such goose neck is present. 
         [0065]    In order to couple the trailer to the crane any suitable connectors  100  could be used between a frame of the crane and the laterally spaced support arms which support the container connector receivers  96 . In one particular embodiment, conventional twist locks are used. The twist locks are inserted in the container connector receivers  96  and the crane has mechanisms for engaging such twist locks similar to the way that the present prior art cranes are being used to lift containers off of ships. The trailers can also be stacked on container ships or barges in order to transfer trailers from one port to another. If desired, forklifts or other lifting devices and structures may be used. 
         [0066]    If desired, as shown in  FIGS. 12-31 , components may be employed for providing such stacking and 20/40 foot interoperability to existing trailers. Thus, such components can be considered a kit to be added to trailers, either by an OEM or new trailer customizer, or in the aftermarket as retrofit parts. Such components need not all be used together, as certain functionality and options are provided by certain components, and the benefits of the individual components may be employed separately. The components are all readily and economically manufactured, and are easily attached to and removed from trailers as desired. Therefore, substantial benefits are provided by using one or more components as described below. 
         [0067]      FIGS. 12-15  show one example of a separate wheel receiving assembly that could be attached to a trailer. Such assembly might also be called a cradle or a saddle, due to the shape. As depicted therein, wheel receiving assembly  200  is attachable to the elongated body of the trailer, for example at beam  202 . Assembly  200  is attachable at a position corresponding to a location of at least one wheel on the trailer, as described above. 
         [0068]    Each wheel receiving assembly  200  includes a central body portion  204 , a fixed upper hook  206  attached to the central body portion, a movable lower hook  208  attachable to the central body portion, and a wheel cradle  210  attached to the central body portion. As shown, a downward depending part  212  of hook  206  fits over beam  202 . Flanges  214  of central body portion  204  contact a central area  216  of beam  202 . Fastening members  218  such as nuts and bolts may be employed to attach movable lower hook  208  to central body portion  204 . Alternately, if desired (not shown), lower hook  208  may pivot down or sideways relative to central body portion  204 . Lower hook  208  is movable in such fashion so that the assembly may be readily yet securely attached to and removed from beam  202 . Thus, to attach the assembly, lower hook  208  is loosed or removed entirely, and upper hook  206  is placed over top portion  220  of beam  202 . Upper hook  206  and cradle  210  are then pivoted down until flanges  214  contact beam  202 . Then, lower hook  208  is attached and/or tightened to hold cradle assembly  200  to beam  202 . The wheel receiving assembly  200  is thus configured to be attachable to the beam  202  by the upper hook  206 , central body portion  204 , and lower hook  208 . 
         [0069]    It should be understood that the individual shapes of assembly  200  may be modified to some extent. For example, cradle  210  could have more or less than three planar sections (sections  210   a, b , and  c  are shown), and the angles of outer sections  210   a  and  210   c  could be changed. Also, cradle  210  could be curved, whether circular or otherwise, sized in relation to a tire to be held. Cradle  210  is shown roughly sized to support an inner tire of a two tire pair, but could be wider if desired. As noted above, alternate attachments and connections between the lower hook  208  and the rest of the cradle assembly are possible as well. Also, upper hook  204  is shown as having one depending portion  212  and lower hook  208  has two upwardly extending portions  222 . The number of extensions and their arrangement could be modified as desired, in particular to meet the particular configuration of a given trailer, its supports, cross-bars, etc. Also, more or fewer fastening elements  218  could be employed. 
         [0070]    Cradle assemblies  200  should be strong enough to support a proportional amount of the weight of a stack of trailers above. Therefore, a high tensile strength steel alloy would be suitable. Domex  110  in ¼ inch plate, cut to size, formed and welded is one possibility, although other materials can be used. 
         [0071]    Certain trailers include triangular reinforcing frame portions at the rear to provide additional rigidity to the trailer. As shown, examples of such elements  97  of trailer  10  are shown in  FIG. 6 . It should be understood that variations exist in trailers currently in use. For example, some plates are higher, some lower; some are atop the beams and some are flush. Therefore, to fit a cradle assembly to a position where it would be centered relative to the rearmost wheel on a given trailer, it might be necessary to modify the cradle assembly from that shown in  FIGS. 12-15 . 
         [0072]    One example of a modified cradle assembly  300  is shown in  FIGS. 16-22 . Cradle assembly  300  is somewhat similar to cradle assembly  200 , and like reference numerals are employed where possible between the embodiments. Thus, cradle assembly includes a central body portion  304 , a fixed upper hook  306  attached to the central body portion, a movable lower hook  308  attachable to the central body portion, and a wheel cradle  310  attached to the central body portion. Hook  306  fits over beam  302  with portion  312  depending downward. Lower hook  308  includes upwardly extending portions  322 . Flanges  314  of central body portion  304  contact a central area  316  of beam  302 . Fastening members  318  attach hook  308  to central body portion  304 , although the connections options above are again possible. 
         [0073]    Cradle  310  and body portion  304  have been modified by removing a portion to fit against a triangular frame portion such as portion  97 . Flanges  314  have been modified and supplemented with a web  315  to provide added strength in view of the removal of some material as compared to the previous embodiment. The exact modification can be done on a case-by-case basis in view of a given trailer. Further, the modification need not be made in view of a triangular reinforcing support. Cradle assemblies can be modified so as to fit around beams of varying width, beams with longitudinal reinforcing, cross-beams, etc. Thus, it should be understood that the two examples of cradles shown above are not to be considered limiting of the inventive cradle concepts. It should also be understood that modifications could be made symmetrically to create cradles that would suit opposite sides of the trailer. 
         [0074]      FIGS. 23 and 24  show an example of a landing gear receiving assembly  400  attachable to a landing gear of a trailer. As shown, landing gear receiving assembly  400  includes an extending body portion  402 . Edges  404  and  406  of the body portion  402  may be bent upward, as with edges of sand shoes  62 , discussed above. Body portion  402  and edges  404  and  406  should be configured large enough to fit the landing gear ends on them without deformation, and should be strong enough to support the weight of the particular trailer and any stacked above it. Also, body portion  402  should be long enough to receive and support any wheels present on a landing gear. Positioning tabs  408  may be provided to help position receiving assembly relative to the landing gear. Holding elements  410  may be provided to secure the landing gear to the body portion, for example by capturing sand shoes  62  (shown in dotted lines in  FIG. 23 ) therebetween once attached. If desired, holding elements  410  may be attached to body portion via fasteners  412  and integral or attached extensions  414 , or holding elements  410  may be attached directly to body portion  402 . If desired, holding tabs could be eliminated and other structures for releasably attaching body portion to the landing gear could be employed, such as hooks, other types of fasteners, etc. Assembly  400  may also be made of ¼ inch Domex  100  or other suitable material. 
         [0075]      FIGS. 25-30  show one example of a container mounting assembly  500  for attachment to a trailer including a beam  502 . Container mounting assembly  500  is in the form of an outrigger that may include a central arm portion  504 , a fixed upper hook  506  attached to the central arm portion, a movable lower hook  508  attachable to the central arm portion, and a container mounting structure  510  attached to the central arm portion. Like the cradle assemblies above, container mounting assembly  500  is configured to be attachable to beam  502  by placing the upper hook  506  over the beam, central arm portion  514  against the beam, and lower hook  508  under the beam. Accordingly, by placing a plurality of such assemblies  500  on a trailer, a trailer may have a container of a given size attached to it by connecting the respective mounting structure of the container with respective container mounting structure of the container mounting assembly. The container mounting assemblies can be mounted to the trailer at respective locations so as to correspond to the size of a shipping container. Thus four such assemblies could be attached for a 20 or even a 40 foot container, or a container of any size that would fit the trailer. Alternately, two such assemblies could be used along with two structures permanently attached to the trailer for structures smaller than the maximum trailer size. Therefore, use of two or more of such assemblies provides flexibility in using trailers so that perhaps only one size of trailer could be used in a port to receive multiple sizes of containers. Again, Domex  110  or other suitable materials can be employed. 
         [0076]    Also, the mounting structure openings  530  can be configured so as to fit connectors used by forklifts or cranes for moving containers. Therefore, the outriggers can serve a dual purpose of adjustably securing shipping containers of various sizes using existing trailers and allowing devices already in ports to be used to move and stack trailers. 
         [0077]    As shown best in  FIG. 27 , central arm portion  514  can be configured so as to extend non-orthogonally from beam  502  (non-symmetrical along longitudinal axis  532 ). Such structure, while not required, can provide added rigidity and security to a container on a trailer, be reducing bending a twisting tendencies. If such is provided, then a symmetrical extension in opposite directions may be desired along and across a trailer. 
         [0078]      FIG. 31  shows a schematic view of on possible arrangement of a kit of component parts on a trailer. As shown, trailer frame  600  has mounting structures  602  to accept a 40 foot container thereon. Four outriggers  604  are provided, 20 feet apart, to receive 20 foot container. If desired, only two such outriggers  604  could be used in conjunction with two of the structures  602 , or the outriggers could be placed alternately. A landing gear receiving assembly  606  is provided attached to landing gear feet  608 . Pairs of first and second cradle assemblies  610 ,  612  are attached to trailer frame  600  at spots corresponding to wheels (not shown in  FIG. 31  for clarity). Note that reinforcing elements  614  are provided on trailer frame  600 , so cradle assemblies  612  are configured to fit adjacent such reinforcing elements while still being in position relative to the respective wheels. 
         [0079]    It should be understood that the arrangement outlined in  FIG. 31  is but one possible kit for use with a trailer. Many variations of such a kit using some, all, or additional parts, and parts attached to trailer frame  600  in various ways, are all possible within the scope of the present disclosure. For example, the trailers may be lashed or otherwise secured together by their frames or by the frames, landing gear assemblies, saddle assemblies and/or the outrigger assemblies for adding stability during use or for shipping groups of stacked trailers. 
         [0080]    Therefore, it should be understood that the types of structures, devices and methods utilized with the teachings of the present disclosure should not be limited to those embodiments shown herein. It should also be understood that features of the various embodiments above may be recombined in other ways to achieve still further embodiments within the scope of the present invention.