Abstract:
Disclosed are systems and methods for a folding vehicle trailer. The trailer design is able to be made of various lengths and widths from as well as multiple axle configurations. This trifold design is compact and allows for vertical stacking of sectionalized components to minimize space, while maintaining great flexibility and simplicity for the end user.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Trailers have been used for centuries, from hand or horse drawn trailers of prehistory, to the vehicular trailers of today. A common similarity that has been possessed by all of these devices is their need to be stored. If space is limited, having a trailer is often not an option. While various attempts have been made to overcome the size demands of a towable vehicular trailer, these efforts have fallen short for a variety of reasons due to their design. These shortcomings are usually realized with a high center of gravity, coupled with a narrow stance and compaction, while in the stored position which often translates to issues of safety. In most prior attempts, additional mechanisms such as cables, clasping mechanisms or removable pins are necessary to facilitate their operation. 
       SUMMARY OF THE INVENTION 
       [0002]    An embodiment of the present invention may therefore comprise: a utility trailer configured to be towed behind a vehicle that facilitates alteration between an open configuration and a compact configuration comprising: a center trailer section comprising: a rigid rectangular center frame chassis; a center bed floor disposed on the front frame; a wheeled axle and suspension system supporting the center frame; and, a pair of collapsible center side barriers pivotally attached to opposing lateral sides of the center frame such that the center side barriers may maintain a normal orientation to the center bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the center bed floor in a compact configuration; a front trailer section comprising: a rigid rectangular front frame chassis; a front bed floor disposed on the front frame; a pair of collapsible front side barriers pivotally attached to opposing lateral sides of the front frame such that the center side barriers may maintain a normal orientation to the front bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the front bed floor in a compact configuration; and, a collapsible front end barrier pivotally attached to the front portion of the front frame such that the front end barrier may maintain a normal orientation or a parallel orientation extending forward of the front bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the front side barriers in a compact configuration; a rear trailer section comprising: a rigid rectangular rear frame chassis; a rear bed floor disposed on the rear frame; a pair of collapsible rear side barriers pivotally attached to opposing lateral sides of the rear frame such that the rear side barriers may maintain a normal orientation to the rear bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the rear bed floor in a compact configuration; and, a collapsible rear end barrier pivotally attached to the rear portion of the rear frame such that the rear end barrier may maintain a normal orientation or a parallel orientation extending rearward of the rear bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the rear side barriers in a compact configuration; a tongue that facilitates connection between the center trailer section and the vehicle; a rearward offset hinge mechanism comprising two offset braces joined by a rear pivot, that pivotally joins the center trailer section and the rear trailer section such that the pivot point of the junction is offset above the center bed floor by a distance of half the combined thickness of the collapsed center side barrier, the collapsed rear side barrier, the rear end barrier, combined with the rear pivot diameter, thereby allowing the rear trailer section to stack directly upon the collapsed center trailer section thereby minimizing the overall stack height of the center and the rear trailer sections; and, a forward offset hinge mechanism comprising two forward offset braces joined by a forward pivot, that pivotally joins the center trailer section and the front trailer section such that the pivot point of the junction is offset above the center bed floor by a distance of half the combined thickness of the collapsed center side barrier, the collapsed rear side barrier, the rear end barrier and the rear trailer section, combined with the forward pivot diameter, thereby allowing the front trailer section to stack directly upon the collapsed rear trailer section when it is stacked directly upon the center trailer section thereby minimizing the overall stack height of the center, the rear and the front trailer sections. 
         [0003]    An embodiment of the present invention may also comprise: a utility trailer configured to be towed behind a vehicle that facilitates alteration between an open configuration, a compact configuration and a stored configuration comprising: a center trailer section comprising: a rigid rectangular center frame chassis; a center bed floor disposed on the front frame; a wheeled axle and suspension system supporting the center frame; and, a pair of collapsible center side barriers pivotally attached to opposing lateral sides of the center frame such that the center side barriers may maintain a normal orientation to the center bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the center bed floor in a compact configuration or stored configuration; a front trailer section comprising: a rigid rectangular front frame chassis; a front bed floor disposed on the front frame; a pair of collapsible front side barriers pivotally attached to opposing lateral sides of the front frame such that the center side barriers may maintain a normal orientation to the front bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the front bed floor in a compact configuration or stored configuration; and, a collapsible front end barrier pivotally attached to the front portion of the front frame such that the front end barrier may maintain a normal orientation or a parallel orientation extending forward of the front bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the front side barriers in a compact configuration or stored configuration; a rear trailer section comprising: a rigid rectangular rear frame chassis; a rear bed floor disposed on the rear frame; a pair of collapsible rear side barriers pivotally attached to opposing lateral sides of the rear frame such that the rear side barriers may maintain a normal orientation to the rear bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the rear bed floor in a compact configuration or stored configuration; and, a collapsible rear end barrier pivotally attached to the rear portion of the rear frame such that the rear end barrier may maintain a normal orientation or a parallel orientation extending rearward of the rear bed floor in an open configuration, and fold approximately parallel to, and stacked upon, the rear side barriers in a compact configuration or stored configuration; a tongue that facilitates connection between the center trailer section and the vehicle, the tongue that remains fixed upon the centerline of the center trailer section in the open configuration, and the tongue that rotates in the plane of the center trailer bed to a normal position to the centerline of the center trailer section in the stored configuration; a rearward offset hinge mechanism comprising two offset braces joined by a rear pivot, that pivotally joins the center trailer section and the rear trailer section such that the pivot point of the junction is offset above the center bed floor by a distance of half the combined thickness of the collapsed center side barrier, the collapsed rear side barrier, the rear end barrier, combined with the rear pivot diameter, thereby allowing the rear trailer section to stack directly upon the collapsed center trailer section thereby minimizing the overall stack height of the center and the rear trailer sections; a forward offset hinge mechanism comprising two forward offset braces joined by a forward pivot, that pivotally joins the center trailer section and the front trailer section such that the pivot point of the junction is offset above the center bed floor by a distance of half the combined thickness of the collapsed center side barrier, the collapsed rear side barrier, the rear end barrier and the rear trailer section, combined with the forward pivot diameter, thereby allowing the front trailer section to stack directly upon the collapsed rear trailer section when it is stacked directly upon the center trailer section thereby minimizing the overall stack height of the center, the rear and the front trailer sections; at least two lower castors positioned on the underside of the center trailer section oriented in a rearward direction; and, at least two upper castors positioned on the underside of the rear trailer section oriented in a forward direction in the open configuration and oriented in a rearward direction in a compact configuration that allow the trailer to be rotated approximately 90 degrees along a centerline from front to back in a compact configuration, to support the weight of the trailer in with the upper castors and the lower castors by raising the tongue from a horizontal orientation to a vertical orientation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    In the drawings, 
           [0005]      FIG. 1  illustrates an isometric view of an embodiment of a folding vehicular utility trailer. 
           [0006]      FIG. 2  illustrates another isometric view of an embodiment of a folding vehicular utility trailer. 
           [0007]      FIG. 3  illustrates an embodiment of the folding frame sections of a folding vehicular utility trailer. 
           [0008]      FIG. 4  illustrates an embodiment of the hinged frame sections of a folding vehicular utility trailer. 
           [0009]      FIG. 5  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0010]      FIG. 6  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0011]      FIG. 7  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0012]      FIG. 8  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0013]      FIG. 9  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0014]      FIG. 10  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. 
           [0015]      FIG. 11  illustrates a latching mechanism of an embodiment of a folding vehicular utility trailer. 
           [0016]      FIG. 12  illustrates a hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. 
           [0017]      FIG. 13  illustrates a hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. 
           [0018]      FIG. 14  illustrates a hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. 
           [0019]      FIG. 15  illustrates a hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. 
           [0020]      FIG. 16  illustrates a spring hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. 
           [0021]      FIG. 17  illustrates a wheel, axle and suspension mechanism of an embodiment of a folding vehicular utility trailer. 
           [0022]      FIG. 18  illustrates another embodiment the containment sections of a folding vehicular utility trailer. 
           [0023]      FIG. 19  illustrates the quantitative analysis equations for the stability of a folding vehicular utility trailer. 
           [0024]      FIG. 20  illustrates an isometric view of an embodiment of a folding vehicular utility trailer configured to maximizing payload length. 
           [0025]      FIG. 21  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with the side containment panels partially folded. 
           [0026]      FIG. 22  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with the side containment panels fully folded. 
           [0027]      FIG. 23  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with the side containment panels fully folded and front and rear panels partially folded. 
           [0028]      FIG. 24  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with all the containment panels fully folded. 
           [0029]      FIG. 25  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with the rear trailer section partially folded. 
           [0030]      FIG. 26  illustrates an isometric view of an embodiment of a folding vehicular utility trailer with the rear trailer section fully folded and the front trailer section partially folded. 
           [0031]      FIG. 27  illustrates an embodiment of a folding vehicular utility trailer with the trailer sections in a fully folded configuration and placed in an upright storage position. 
           [0032]      FIG. 28  illustrates an embodiment of a folding vehicular utility trailer showing the pivot function of the trailer tongue. 
           [0033]      FIG. 29  illustrates an embodiment of a folding vehicular utility trailer with the tongue in a fully folded configuration. 
           [0034]      FIG. 30  illustrates a pivot and retainer mechanism for the tongue section of an embodiment of a folding vehicular utility trailer. 
           [0035]      FIG. 31  illustrates another view of a pivot and retainer mechanism for the tongue section of an embodiment of a folding vehicular utility trailer. 
           [0036]      FIG. 32  illustrates an embodiment of a double axle embodiment of a folding vehicular utility trailer. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    While this invention is susceptible to embodiment in many different forms, it is shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not to be limited to the specific embodiments described. 
         [0038]    Conventional vehicular trailers mentioned above have many limitations. The disclosed embodiments provide a trailer that is stable and secure in the folded or unfolded orientation providing additional safety in its use and storage. These designs accomplish this without the reliance upon removable pins and additional parts. The disclosed embodiments readily, quickly and easily fold into a highly compact form that facilitates a very low center of gravity and a dense collection of the mass (low volume) and maintains maneuverability while in either state of assembly. 
         [0039]      FIG. 1  illustrates an isometric view of an embodiment of a folding vehicular utility trailer. As shown in  FIG. 1 , the trailer comprises a bed floor, and a frame of several sections and components that when properly configured, combine to make a larger trailer. The trailer bed is made up of three smaller segmented sections, the front trailer section  32 , center trailer section  34  (mid-section) and a rear trailer section  36 . Left lateral side barriers  90   a ,  90   b ,  90   c  and right lateral side barriers  92   a ,  92   b ,  92   c  and end barriers  70 ,  110  are mounted to the front and rear trailer sections respectively to provide containment sections for the trailer payload. When end barriers  70 ,  110  are laid out horizontally and outward from the ends of the trailer they act to provide additional bed length for the trailer and allow the payload to overhang the bed length, thereby providing capacity for long items to be transported. 
         [0040]      FIG. 1  illustrates the unfolded operating position of the trailer and all side barriers  90   a ,  90   b ,  90   c ,  92   a ,  92   b ,  92   c  are shown extended and locked for transporting a payload. Each of these barriers is pivotally hinged to fold inward and flat against the bed floor for folding or for a flat-bed trailer option. Similarly, end barriers  70 ,  110  fold inward, as well as outward, from the center of the trailer to accommodate various positions and functions. 
         [0041]    The trailer is divided in to the three aforementioned trailer sections  32 ,  34  and  36  by two parting lines  38   a ,  38   b . These trailer sections are pivotally connected (hinged) to each other along the parting lines, as shown with the front and rear trailer sections  32 ,  36  pivotally connected (hinged) attached to end barriers  70 ,  110  on the ends of the trailer and make up two additional part lines  38   c ,  38   d.    
         [0042]    The front and rear trailer sections  32 ,  36  are structurally contained at the forward most and rearward most corners utilizing flat plate hinges  76  that perform multiple functions in the operation of the trailer. First, the flat plate hinges  76  attach the end barriers  70 ,  110  to the trailer. Second, they allow each end barrier  70 ,  110  to be folded out from the trailer  30  at a position that is level with the bed floor. Third, they allow the end barrier  70 ,  110  to be folded backward and up over the top of the front trailer section  32  and rear trailer section  36  respectively, and further allow the side barriers  90   a ,  90   b ,  90   c  and  92   a ,  92   b ,  92   c  to fold underneath. Additionally, the flat plate hinges  76  allow the end barriers  70 ,  110  to stand alone vertical upright to the horizontal bed floor. 
         [0043]    The center trailer section  34  serves as the structural foundation for the trailer to which the additional components attach. The attachments to the center trailer section  34  encompass the trailer tongue  156  and the front and rear trailer sections  32  and  36 , with their respective components. The tongue  156  is held into position by a tongue slide  158  (shown and described in detail below). The tongue slide sway tab saddle  132  comprises two tongue slide sway tabs  133   a ,  133   b  on the bottom of the front frame section  42  (chassis) and the front cross member bed  48   a . The locking tongue spring pin  131  pass through an aperture on the sway tabs  133   a ,  133   b , the tongue slide  158 , and through the tongue  156 , which locks the tongue in place for towing. On the back of the tongue  156  is a tongue stop blocker  312  that prevents the tongue  156  from exiting from the tongue slide  158 . This prevents disengagement as a safety measure in an instance where the locking tongue spring pin  131  is not engaged. The stop blocker  312  makes contact with blocker  314  in the tongue slide at a predetermined distance (see  FIG. 26 ). 
         [0044]      FIG. 2  further illustrates the embodiment of a folding vehicular utility trailer shown in  FIG. 1 . As is also illustrated in  FIG. 1 , left lateral side barriers  90   a ,  90   b ,  90   c  and right lateral side barriers  92   a ,  92   b ,  92   c  are comprised of side barrier tubes  95  and side barrier skin  93  and are all similar and are universally utilized. Each end barrier  70 ,  110  possess a similar skin and tube design as the side barriers, and are shown as end barrier tubes  72  and end barrier skins  74  respectively, but are longer then the side barrier tube rails  95  and side barrier skins  93  and are also universally utilized on either end of the trailer. 
         [0045]      FIG. 2  also shows the front frame section  42  with front end barrier folded lock tab  130   a  attached to the front frame side rail  50   a , and rear frame section  46  (chassis) with rear end barrier folding lock tabs  130   b  attached to the left rear frame side rail  62   a . These lock tabs are utilized in conjunction with a single-finger spring pin latch  114  when an end barrier  70 ,  110  is placed into a folded position (as shown in  FIGS. 9 and 24 ).  FIG. 2  additionally shows a tail light  126  that is attached by fastening to the tail light guard and grab handle  128 , which is attached to the rear frame section side rails  62   a ,  62   b.    
         [0046]    Also shown in  FIGS. 1 and 2 , are the rear end barrier  110  and front end barrier  70  which are attached to the two flat plates hinges  76  (further detailed in  FIG. 5 ), which are attached rearward to the rear frame side rails  62   a ,  62   b , and forward to the front frame side rails  50   a ,  50   b . The rear end barrier  110  and front end barrier  70  latch in an upright vertical position on both the left and right side utilizing a spring pin latch  114  (also detailed in  FIGS. 8 and 9 ). The right and left side of each end barrier  110 ,  70 , has a single-fingered spring pin latch  114 , and a universal finger parking tab  118  (further detailed in  FIGS. 6 ,  7  and  8 ). 
         [0047]    The universal finger parking tabs  118  allow the entire single-finger spring pin latch  114  to rest on the parking tab  118 , thereby keeping the spring finger pin latch  114  from being engaged through the aperture in both the universal finger parking tab  118  and universal locking tab  116 . The front and rear side barriers  90   a ,  90   c  and  92   a ,  92   c  contain universal locking tabs  116 . When the single-finger spring pin in latch  114  is rotated onto the universal finger parking tab  118 , the end barrier  70 ,  110  may then be raised or lowered. When the universal locking tabs  116 , in conjunction with the universal finger parking tabs  118  and single spring pin latches  114 , engage into the aperture  116 ,  118 , it secures the end barriers to the upright side barrier tubes  95  when end barrier and side barrier are abutted in the upright vertical position as shown in  FIG. 2 . 
         [0048]      FIGS. 1 and 2  further depict the left side barriers  90   a ,  90   b ,  90   c  and right side barriers  92   a ,  92   b ,  92   c , which are interchangeable and attached with butterfly hinges  94  (detailed in  FIG. 12 ). In this embodiment, one side of the butter fly hinge  94  attaches to the front frame side rails  50   a ,  50   b , center frame side rails  56   a ,  56   b , and rear frame side rails  62  and  62   b  rear, while the other side of the butter fly hinge  94  attaches to side barrier tube  95 . The butterfly hinge utilized in this embodiment has an offset pivot point  91  that facilitates the engagement when the upper end of left side barriers  90   a ,  90   b ,  90   c  and right side barriers  92   a ,  92   b ,  92   c    90   a ,  90   b ,  90   c  rotate for storage, and the upper end of side barrier tube  95  abuts when laid down onto the top of the front, center, and rear bed floor  22 ,  24 ,  26 . 
         [0049]    The side barrier tubes  95  lower-end rotates up and over the offset pivot point  91  (detailed in  FIG. 12 ) of the butterfly hinge  94 , and remains above the bed floor  22 ,  24 ,  26 . This lower end of side barrier tube  95 , remains above the bed floor  22 ,  24 ,  26  and facilitates the exterior side barrier tab/strap  96   a ,  96   b , to engage and align the outward side barriers  92   a ,  92   c  and  90   a ,  90   c  respectively while adjoining all side barriers together for raising and lowering all side barriers simultaneously. Additionally, when side barriers  90   a ,  90   b ,  90   c  and  92   a ,  92   b ,  92   c  are rotated to the vertical standing up position, (detailed in  FIG. 20 ) the offset pivot point  91  rotates the side barrier tube  95  up, over and down onto the frame side rails  50   a ,  50   b ,  56   a ,  56   b , and  62   a ,  62   b . When these side barriers are rotated vertically, this unloads the rotation point  91  of the butterfly hinge  94  and puts the side barrier rail into compression on top of frame side rails  50   a ,  50   b ,  56   a ,  56   b  and  62   a ,  62   b  to take the vertical download placed upon the side barriers  90   a ,  90   b ,  90   c  and  92   a ,  92   b ,  92   c.    
         [0050]    As further detailed in  FIGS. 13 and 14 , side loads placed upon the side barriers  90   a ,  90   b ,  90   c  and  92   a ,  92   b ,  92   c  are carried by the rear and front side barrier hinges  108  and  109  respectively, and vertical support members  84  when locked by a spring latch  100  and a locking tab  101 . The locking tab  101  is attached to the front side of the side barrier  90   b  and  92   b  of and extends off of side barrier tube  95 . 
         [0051]    The center side barriers  90   b  and  92   b  have exterior adjoining side barrier tabs  96   a ,  96   b  and interior adjoining side barrier tabs  98   a ,  98   b . The exterior adjoining side barrier tab on the center side barrier  90   b  and  92   b  make contact with the front side barriers  90   a ,  92   a  and rear side barriers  90   c ,  92   c , thereby allowing all of the individual side barriers to be lowered into the down position as a single unit onto the bed floor  22 ,  24 ,  26 . Side barriers  90   b  and  92   b , interior side barrier adjoining tabs  98   a ,  98   b  (further detailed in  FIG. 4 ), make simultaneous contact with the front and rear side barriers  90   a ,  92   a , and  90   c ,  92   c  respectively, allowing the three side barriers to be raised into the vertical position together as a single unit, as further shown in  FIGS. 20 and 21 . 
         [0052]      FIG. 3  illustrates an embodiment of the folding frame sections of a folding vehicular utility trailer. The front trailer section  32  comprises a front bed floor  22 , a front cross-member  48   a , a middle cross-member  48   b , and a rear cross-member  48   c . All three front cross members  48   a ,  48   b ,  48   c  of the front frame section  42  (chassis) attach on the outboard sides, which are the left and right front frame side rails  50   a ,  50   b.    
         [0053]    The center trailer section  34  comprises a center bed floor  24 , a front cross member  54   a , a center cross member  54   b , and a rear cross member  54   c . All three cross members  54   a ,  54   b , and  54   c  of the center frame section  34 , attach on the outboard sides to the left and right center frame side rails  56   a ,  56   b . The center trailer section  34  also utilizes two additional reinforcing diagonal frame members  55  and  57  creating a figure “A” and an additional vertical reinforcing center frame member  58  that is attached to the middle of the front cross member  54   b  and spans to the middle of the rear cross member  54   c . The center trailer section  34  is the structural foundation for the trailer to which all the rest of the trailer sections are attached. As detailed if  FIGS. 1 and 2 , the center trailer section  34  attaches to the trailer tongue  156 , axle  138 , springs  134  and front and rear trailer sections  32  and  36 . 
         [0054]    The rear trailer section  36  comprises a rear bed floor  26 , a front cross-member  60   a , a middle cross-member  60   b , and a rear cross-member  60   c . All three cross members  60   a ,  60   b ,  60   c  of the rear frame section  36  attach on the outboard sides, which are the left and right front frame side rails  62   a ,  62   b.    
         [0055]    In this embodiment, the front trailer section  32  also comprises the front end barrier  70 . The front end barrier further comprises the front end barrier tube rail  72  and front end barrier skin  74 . The front end barrier  70  rotates ninety-degrees in either direction from the vertical points of attachment  73   a ,  73   b  (as detailed in  FIG. 6 ) so that it may either lay flat towards the front of the trailer, or to the rear of the trailer. The front end barrier  70  is attached to the structure of the front trailer section  32  utilizing flat plate hinges  76 . As detailed in  FIG. 5 , the flat plate hinge  76  utilizes two components; a flat hinge plate  77 , and a hinge plate vertical support member  84 . The flat plate hinge  77  is interchangeable to any lateral side of the trailer by simply rotating the hinge plate vertical support member  84  to the desired position on all four corners of the trailer. 
         [0056]    The trailer tongue  156  that connects the center trailer section  34  to the towing vehicle serves three functions in the disclosed embodiments. First, the tongue  156  acts as a fulcrum to rotate the trailer from a horizontal towing configuration (as shown in  FIG. 1 ) to a vertical stored configuration (as shown in  FIG. 27 ). Second, when the trailer is in this vertical stored configuration, the tongue  156  may rotate ninety-degrees in either direction, from the twelve o&#39;clock position, to the three and nine o&#39;clock positions, (i.e., a horizontal position), for additional storage room and removal of its use as a fulcrum, which provides safety from unintentional rotation from a vertical stowed position, to horizontal tow position (see  FIG. 29 ). The third function of the tongue  156  is its utility as a handle to maneuver the trailer upon the casters  172  (detailed in  FIGS. 27 and 29 ) when folded into the storage vertical configuration. 
         [0057]      FIG. 4  illustrates an embodiment of the hinged frame sections of a folding vehicular utility trailer. As detailed in  FIG. 4 , all of the side barriers  90 ,  92  and end barriers  70 ,  110  are folded into their flat configuration. This allows the rear trailer section  36  to pivotally hinge and rotate forward about a pair of rear side barrier hinge  109   a ,  109   b , thereby allowing the bed section to be placed on top of the center trailer section  34 . Similarly, the front trailer section  32  may also pivotally hinge and rotate rearward about a pair of front side barrier hinges  108   a ,  108   b  thereby allowing the bed section to be placed either directly on top of the center trailer section  34  or upon the rear trailer section  36  that is in the folded configuration. 
         [0058]      FIG. 5  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. As shown in  FIG. 5 , the flat plate hinges  76  have two hinge plate aperture points of attachment  80 ,  82  at opposite diagonal corners of the flat hinge plate  77 . The hinge plate aperture points of attachment  80  function by utilizing bolts  79   b , which pass through apertures  80  in the flat hinge plate  77  and the hinge plate vertical support member aperture of attachment  85   a  of the hinge plate vertical support members  84  (see exploded portion of  FIG. 5 ). The point of attachment of the lower hinge plate aperture  82  allows the front end barrier  70  and rear end barrier  110  to be attached to the front trailer section  32  and rear trailer section  36  respectively (see  FIG. 6  and  FIG. 20 ). 
         [0059]    Attached to the bottom portion of the front and rear end barrier tube rail  72 , is an extension arm  88  that extends outward from the front and rear end barrier tube rail  72  at ninety-degrees. This extension arm  88  creates a moment between the hinge plate aperture point of attachment  82 , and the end barrier tube rail  72 , thereby enabling the end barrier to exert a downward force causing rotation when positioned vertically to the plane of the front trailer section  32  and rear trailer section  36 . This rotation causes the hinge plate vertical support member  84  and the rest point plane  86  to exert a force back against the end barrier tube rail  72 , thereby stopping the rotation of the front end barrier  70  and the rear end barrier  110 . As further detailed in  FIG. 22 , this moment between the extension arm  88 , the vertical support member  84 , and the trailer front and rear end barriers  70 ,  110 , allows for these end barriers  70 ,  110  to remain vertical and upright while the trailer is at rest. This feature is exemplified in the folded configuration depicted in  FIG. 24 , which allows either of the end barriers  70 ,  110  to remain in a stand-alone vertical position while the side barriers  90 ,  92  are manipulated into the vertical (up) or horizontal (down) position. 
         [0060]    The rest point  87  of the hinge plate vertical support member  84  extends high enough above the folded side barriers  90   a ,  90   b ,  90   c ,  92   a ,  92   b ,  92   c , which are resting flat on the bed floor so that the hinge plate vertical support member  84 , in conjunction with the flat hinge plate  77 , to allow the front and rear end barriers  70  and  110  to be folded up over the rest point  87  as well as the side barriers  90 ,  92 . When positioned in this configuration, the hinge plate  77  is rotated out of the U-Stop  84   a  on the vertical support member  84 . The hinge plate vertical support member  84  is “L” shaped and also comprises a U-stop  84   a  containing two holes  85   a ,  85   b . When the end barriers  70 ,  110  are moved into a vertical position as exemplified in  FIGS. 1 ,  21  and  22 , or in a flat outboard position as exemplified in  FIG. 20 , the hinge plate  77  is engaged by the U-stop  84   a  and provides lateral stability to the flat hinge plate  77 . 
         [0061]      FIG. 10  illustrates the containment sections of an embodiment of a folding vehicular utility trailer. As detailed in  FIG. 10 , an end barrier cable  120  located on both the left and right sides of the end barriers  70 ,  110  are attached by the upper and lower end barrier cable tabs  122   a ,  122   b  and  124   a ,  124   b  respectively. These end barrier cables  120  allow the end barrier  110  to be lowered and retained in a flat orientation much like the open tailgate of a pickup truck. 
         [0062]    As further detailed in  FIG. 13  and  FIG. 14 , the front side barrier hinges  108   a ,  108   b  and the rear side barrier hinges  109   a ,  109   b  are each comprised in this embodiment of two pieces. This involves an inverted “L” member  102   a ,  103   a  that interfaces with an offset brace  102   b ,  103   b  by means of a pivot  104 ,  105 . This pivot interface comprises a pair of through-holes placed at the horizontal leg of the inverted “L”  102   a ,  103   a , and at distal end of the offset brace where a pivot  104 ,  105  (e.g., bolt or rivet or the like) passes through the apertures and allows rotation (see  FIG. 15 ). The vertical height of the rear side barrier hinges  109   a ,  109   b  is shorter than the vertical height of the front side barrier hinges  108   a ,  108   b . This allows the stacking of the front trailer section  32  on top of the rear trailer section  36  when the trailer is in a folded configuration. 
         [0063]    The front and rear side barrier hinges  108 ,  109  serve multiple functions within the folding vehicular utility trailer. The rear side barrier hinge  109  rotates and allows the rear trailer section  36  to transition to a folding position along with the folded side barriers  90   c ,  92   c  and the folded end barrier  110 . This assembly rotates up and over the top of the center trailer section  34  including the folded center side barriers  90   b ,  92   b . The front side barrier hinge  108  similarly rotates and allows the front trailer section  32 , along with the folded side barriers  90   a ,  92   a  and folded end barrier  70 , to rotate up and over the top of the stacked rear trailer section  36  and center trailer section  34  (see  FIG. 26 ). This rotation is facilitated with two rear side barrier hinges  109   a ,  109   b  one on each side of the center and rear trailer sections  34 ,  36 . This same type of hinged rotation is repeated with the two front side barrier hinges  108   a ,  108   b  on each side of the front and center trailer sections  32 ,  34 . 
         [0064]    The front and rear side barrier hinges  108 ,  109  additionally serve to stop the rotation of the side barriers  90 ,  92  from moving outward beyond ninety degrees when the side barriers  90 ,  92  are in a vertical position. This is accomplished by providing a stop in conjunction with a spring latch  100  and a locking tab  101  (see  FIG. 11 ). With the side barrier  90 ,  92  in a vertical position, the bed sections may lock in the open position (see  FIG. 27 ). The side barrier hinges  108 ,  109  must also translate the stacked collection of the outer front and rear trailer sections horizontally and away from one another so that when they are rotated and stacked, their rotated inner edges do not strike each other. When the front trailer section  32  is folded up and over the rear trailer section  36 , this translation and the sequence of its operation provides stability and utilizes the weight of each successive layer to provide a secure placement of the trailer sections in both the folded and storage configurations. When the trailer sections are rotated vertical, the above layered method and sequence prevents the trailer sections from opening. The side barrier hinge  108 ,  109  design&#39;s utilization of gravitational forces that inhibit the trailer sections from configuration transition in the open and folded configuration. 
         [0065]    The side barrier hinges  108 ,  109  facilitate horizontal translation of the front and rear trailer sections  32 ,  36  by utilizing a displacement of the pivot (point of rotation)  104 ,  105  on the horizontal leg of the inverted “L”  102   a ,  103   a , which facilitates a displacement of the part line  106 ,  107  when the side barrier hinge  108 ,  109  is rotated. 
         [0066]    Figure illustrates a hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. As shown in  FIG. 13 , the inverted “L”  102   a  of the front side barrier hinge  108   a , is positioned at an offset distance to one side (shown in  FIG. 13  to the right), and the offset brace  102   b  is positioned at an offset distance to the opposing side (shown in  FIG. 13  to the left), to the left of the part line  106 . The part line  106  is shown to the right of the pivot (point of rotation)  104 .  FIG. 15  further illustrates the part line  106  comprising a right side  106 R of the offset brace  102   b  and left side  106 L of the inverted “L”  102   a . Both of these parts  106 R,  106 L come in contact to form the part line  106 . The inverted “L”  102   a  is affixed to the center frame side rail  56   a  with the pivot (point of rotation)  104  extended out over the outer front trailer section  32 . 
         [0067]    When front trailer section  32 , is rotated 180 degrees, from the open position, up and over the top of the center trailer section  34 , the offset brace  102   b  side of the part line  106 R is facing in the opposite direction, from the open trailer position. The offset brace  102   b  and its side of the part-line  106 R are now facing to the left, where when un-rotated  106 R was facing to the right. The difference in the horizontal distance from the left to the right of the offset brace side of the part-line is the horizontal distance of the transition backwards of the front trailer section  32 . This results in a backward transitional distance that prevents the outer portion of the front trailer section  32  from striking the rear trailer section  36  when they are both rotated over the center trailer section  34 . The same backward transitional distance described above, applies to the rear bed section  36  and its side barrier hinge  109 . 
         [0068]    Another advantage of the operation and design of side barrier hinges  108 ,  109  is that they allow vertical stacking/layering of all the trailer components (i.e., trailer sections  32 ,  34 ,  36  as well as the folded side and end barriers  90 ,  92 ,  70 ,  110  in a condensed layered manner (see  FIG. 26 ). As mentioned above, to facilitate this stacking/layering, the rear side barrier hinges  109  are shorter than the front side barrier hinges  108 . The pair of upside inverted “L” hinges  102   a ,  103   a  are fixed to the center trailer section corners  34  with the horizontal part of the “L” and rotational point  104 , 105  being out over the outer folding section  32  and  36 . The vertical portion of the inverted “L” hinges  102   b ,  103   b  are fixed to the adjacent adjoining corners of the front and rear trailer sections  32 ,  36 . This offset vertical part  102   b  and  103   b  fits any adjacent corner by just rotating it about the vertical axis 180-degrees. The arm length of the rear side barrier hinge  109  is determined by dividing the combined thickness of the rear trailer section stack and the center trailer section stack by two, then adding the bolt diameter. The arm length of the front side barrier hinge  108  is determined by dividing the additive of the rear trailer section stack thickness, the center trailer section stack thickness and the front trailer section stack thickness, by two, then adding the bolt diameter. By vertically stacking (layering) the bed sections utilizing the side barrier hinges  108 ,  109 , the mass of the trailer sections  32 ,  34 ,  36  is collected into a tight condensed space maximizing the reduction in volume from an open configuration, to compact configuration, to a stored configuration. 
         [0069]    When the trailer is in a folded configuration, with the front trailer section  32  folded over the top of the rear trailer section  36 , it is then easily rotated as a unit from a horizontal stack to a vertical stack (stowed configuration). In this orientation, the hinge mechanisms continue to prevent opening of the sections utilizing gravitational force to keep the sections intact. This is facilitated by the folding sequence. In the open configuration, the front trailer section  32  and rear trailer section  36  also utilize gravitational forces in combination with the moments of the trailer sections and the moment arms created by the offset braces  102 ,  103  to maintain an open and stable condition. Therefore, the need for locking mechanisms is unnecessary. This reduces part count, complexity, weight and cost, while increasing safety, simplicity and reliability. The reason locking mechanisms are unnecessary, is that the force acting over a distance from a point of rotation of the offset aperture  104 ,  105  to the free opposite end of the rear trailer section  34  and the front trailer section  32 . The gravitational force in this embodiment is pulling down on the front and rear trailer sections  32 ,  36  at a normal angle to the inverted “L”  102   b ,  103   b  in conjunction with the length of the arm down from the rotational point  104 ,  105 , thereby exerting a large closing force on the part line  106 ,  107  of the hinge. 
         [0070]    Without the need to latch and unlatch any items, the transition time for changing configurations is lessened. The side barrier hinge  108 ,  109  additionally transfers the entire weight of the front and rear trailer section  32 ,  36  to the center trailer section  34 , and no additional support is required to transfer their respective load. When the side barrier hinges  108 ,  109  are combined with the vertical side barriers, and with inclusion of the vertically mounted spring bolt latch  100  that is mounted to the outside of the inverted “L”  102   a  of the side barrier hinge  109 , and, with a tab  101  and its aperture that is mounted to the side barrier tube  95 , the mechanism, and the vertical side barrier, are very stable in the open configuration. 
         [0071]      FIG. 16  illustrates a spring hinge and retainer mechanism of an embodiment of a folding vehicular utility trailer. As shown in  FIG. 16 , the side barrier hinges  108 ,  109  may optionally comprise a hinge assist spring  99  and spool  99   s  that mounts in alignment to offset aperture  104 ,  105  and the retaining bolt. This spring has two stems  97   a ,  97   b  that protrude from the spring and into an aperture (or slots in the transitional side barrier hinge  108  and  109 ). The weight of the component of the trailer sections  32 ,  36 , as well as the side barriers  90   a ,  90   c ,  92   a ,  92   c  and the end barriers  70 ,  110 , is offset by the spring forces. Although this transitional hinge spring is not needed for operation, additional ease of use could be realized utilizing a decrease in rotational force when rotating the front and rear trailer sections  32 ,  36 . 
         [0072]      FIG. 17  illustrates a wheel, axle and suspension mechanism of an embodiment of a folding vehicular utility trailer. As shown in  FIG. 17 , an axle spring  134  is attached to a spring channel  136 , which is connected to the center frame side rails  56   a ,  56   b . The trailer axle  138  is affixed to the axle springs  134 . The trailer tire unit (wheel and tire)  140  is attached to the wheel hub  142 , which is attached to the axle  138 . 
         [0073]    As displayed in  FIGS. 27-29 , an elongated, multi-length, pivoting tongue assembly  155  has a tongue  156  that extends forward out of tongue slide  158  and is attached to the center frame section  34 . The tongue  156  and tongue slide  158  run beneath, but are not attached to the front trailer section  32 , until the sway tab saddle  132  is engaged with sway tabs  133   a ,  133   b , and additionally with the locking tongue spring pin  131  (see  FIGS. 4 and 5 ). 
         [0074]    The tongue slide  158  is rotatably attached to the center trailer section  34  using a tongue rotatable joint  150  and a center tongue slide locking tab  152 , rotated into center torsional tongue slide saddle  154  (detailed in  FIGS. 28-30 ), which is attached to the front cross member  54   a  and diagonal bed member  55 ,  57  of the center trailer section  34 . The tongue slide is also attached by the rear tongue slide locking tab  160  and the rear tongue slide saddle  162  (further detailed in  FIG. 31 ). As stated above, the tongue slide  158  has two locking tabs, a center tongue slide locking tab  152  and a rear tongue slide locking tab  160 . 
         [0075]      FIGS. 28-31  illustrate an embodiment where the center tongue slide locking tab  152  and the rear tongue slide locking tab  160  move into the center torsional tongue slide saddle  154  and rear tongue slide saddle  162 , when the tongue slide is rotated to a twelve o&#39;clock position. The center torsional tongue slide saddle  154  restricts torsional movement of the tongue slide  158 . When rear tongue slide saddle  162  engages the tongue slide  158 , it prevents the tongue  156  from moving up and down, while also preventing motion in the front-to-back direction. This engagement also holds the tongue slide  158  parallel to the center trailer section  34 . This movement restriction is achieved by fixating the tongue slide saddle  154  and the rear tongue  162 , in combination with the tongue slide sway tab saddle  132  engaging tongue slide  158  when the front bed section  32  is lowered onto the tongue slide  158 . In addition, the tongue spring pin lock  131 , while also engaging the preset aperture in the tongue  156  in place and the tongue slide  158  preset aperture and sway tabs  132   a ,  132   b , thereby securing the tongue  156  in place and adds an additional securing means to hold the tongue slide  158 . 
         [0076]    The fixated rear tongue slide spring locking pin  164  and the center tongue slide spring locking pin  165  add an additional mechanism of fixation (safety) to the locking of the tongue slide  158  when towing, as well as functioning as a fulcrum for movement of the trailer from the horizontal to the vertical stowed position or visa-versa. The tongue  156  can also be positioned in a telescoping manner, out of the tongue slide, to provide additional and variable tongue length depending upon the needs of the user. This tongue length is locked in place by a tongue spring locking pin  153 , when engaged to a preset aperture placed in the tongue  156  and the tongue slide sway tab saddle  132   a ,  132   b  aperture. The tongue saddle rear locking assembly  167  is comprised of the rear tongue slide locking tab  160 , the rear tongue slide saddle  162  and rear tongue slide spring locking pin  164  and can be attached or positioned in multiple points along the vertical reinforced center frame members  58  of the center trailer section  34  to engage the tongue slide  158 . Because the tongue slide  158  and tongue  156  rotate together, and rotate from the three and nine o&#39;clock positions to the twelve o&#39;clock position (and vice versa) with the trailer in the vertical position, many combinations of length of the tongue slide  158  or tongue  156  may be used with a wide variety of trailer sizes. 
         [0077]      FIG. 18  illustrates another embodiment of the containment sections of a folding vehicular utility trailer. In this embodiment, the flat plate hinge  76  shown in  FIG. 4  and  FIG. 5  that is used in folding the end barriers  70 ,  110  on top of the folded side barriers  90 ,  92 , may be replaced with an offset hinge  300 . This embodiment is facilitated by a unique right and left hinge. The offset hinge  300  has a vertical support  301  attached to frame side rails  50   a ,  50   b ,  62   a ,  62   b  and is pivotally attached at the upper corner. The aperture  303  of the vertical support aligns with another aperture  305  of an “L” shaped offset plate  302 . An extension arm  304  is located toward the bottom portion of the “L” shape offset plate and is positioned at a ninety-degree orientation outward from the outer ends of the front trailer section  32  and the rear trailer section  36 . 
         [0078]    At the end of that extension arm  304  is an aperture  306  for attaching the extension arm  88  of the rear end barrier  10  containing an aperture  307 . This allows the end barrier  110  to contact the “L” shape offset plate surface  308 , and hold the end barriers vertical. The end barrier  110  has the same downward force keeping it vertical as previously described in the flat plate hinge  77  described in other embodiments. The operation of the end barriers  70 ,  110  are similar in each of these embodiments. To summarize the mechanical difference between the offset hinge  300  and the flat plate hinge  76 , the “L” shaped portion of the offset hinge  300  rotates, and embodies a right and left hinge component for each corner, whereas the “L” shape portion of the flat plate hinge  76  is fixed, does not rotate, and has no restriction as to orientation, and thus, applies universally to any corner. 
         [0079]    The trailer  30  also can be broken down for shipping into multiple components. This is accomplished by utilizing any variety of fasteners with the trailer sections  32 ,  34 ,  36  as well as the end and side barriers  90 ,  92 ,  70 ,  110 . Additionally, the tongue  156  and tongue slide  158  and the wheel axle assembly  175  may be separated. 
         [0080]    In addition to the single axle design utilizing the wheel axle assembly  175  disclosed in the above described embodiments, a second axle  206  may be added to the above trailer embodiments to realize a double axle vehicular trailer. As shown in  FIG. 32 , a second axle assembly is placed forward of the wheel axle assembly  175 . The first axle  138  is placed in a similar manner to the embodiment disclosed in  FIGS. 17 and 18 , placing it on the center trailer section  34 . The first and second axle suspension intermingles to forms a dual axle utilizing in this embodiment a three-point rocker  200  and additional set of front leaf spring  208  attached to the second axle  206 . Other types of axles may be utilized in addition to the spring and rocker mechanism disclosed, and fall within the spirit of the disclosure, such as a torsional suspension, straight axle or the like. 
         [0081]    A typical trailer suspension distributes trailer load in roughly a 60/40 weight distribution split to maintain a downward tongue weight. This design keeps a trailer from swaying back and forth while being towed (this is known as hunting). In order to keep this 60/40 split, the center trailer section  34  or the front trailer section  32  can be increased in length or a combination of both. The rear trailer section  36  typically remains constant, and will not have any striking of components when folded, which is elevated by the side barrier hinges  108 ,  109 . The operational and mechanical aspects of the dual axle design remain constant as detailed above. 
         [0082]    The operations of the trailer  30  of the disclosed embodiments will now be described and associated with their benefit. The trailer  30  is designed to keep all parts interconnected to each other, both in the open, compact or stored positions in order to insure that no parts are separated or left unattached unintentionally, potentially causing a hazardous situation. The trailer  30 , in the complete open position, would be ready for towing simply by attaching the coupling  166  (see  FIG. 26 ) and locking it down over the ball hitch of the towing vehicle. While in the open/towing configuration, the front end barrier  70  and the rear end barrier  110  may be either in the up and fixed position (i.e.,  FIG. 1 ) or placed flat (i.e.,  FIG. 20 ) to increase towing capacity. This is accomplished by releasing the front and rear end barriers  70  and  110  respectively, by disengaging the left and right single-finger spring pin latches  114 , from the front and rear of the trailer by pulling back and rotating the fingers of the spring pin latches onto the finger parking tabs  118  and releasing (see  FIGS. 6-9 ). This disengages the fingers from the universal locking tabs. The front end barriers  70 ,  110  may be then be laid down to rest on the tongue  156 . The rear gate  110  may be lowered and fixed utilizing the attached end barrier cables  120  that were detailed in  FIG. 10 . Lowering the end barriers gives the user the option of extending the bed length and carrying capacity for longer payload. 
         [0083]    To place the trailer  30  into a compact state, the user will access the handle of the side barrier spring latch  100  (see  FIGS. 2 and 11 ) located on the side barrier hinge  108  and release the passenger side barriers  90 . The user will lay the interlock side barriers downward simultaneously toward the inside of the trailer onto the bed floor  22 ,  24 ,  26  of the front, center and rear trailer sections  32 ,  34 ,  36  (see  FIG. 21 ). The user will now repeat this process laying down the side barriers  92  on the opposing side. The side barriers  92  are able to be laid down simultaneously due to the exterior adjoining side barrier tabs/straps  96   a ,  96   b  shown in  FIGS. 4 and 21 . When being placed back into the upright position, the interior side barrier adjoining tab/straps  98   a ,  98   b  make it possible for side barriers to be raised simultaneously with one action and not individually. Laying down all side barriers may automatically disengage the single-finger spring pin latch  114  of the right side and left side of all side barriers  90 ,  92  and end barrier  70 ,  110  in the adjoining intersecting corners. At this point, the front end barrier  70  and rear end barrier  110  are ready to be folded inward. 
         [0084]    The front end barrier  70  is then pulled down until the single-finger spring pin latch  114  engages into the aperture of the end barrier folded lock tab  130   a ,  130   b  on the front trailer section  32 . The rear end barrier  110  is similarly pulled down to the inside of the trailer and there is very little clearance between components. The single-fingered spring pin latch  114  may also automatically engage into end barrier folded lock tab  130   a ,  130   b  on the rear trailer section  36  by the weight of the rear end barrier  110  when the end barriers  70 ,  110  are folded up and over the top of the previously folded and stored side barriers  90 ,  92 . This retention mechanism is only need to keep the end barriers  70  and  110  and side barriers  90   a ,  90   c ,  92   a ,  92   c  secure, as the front and rear trailer sections  32 ,  36  are folded one on top of one another (see  FIGS. 25 and 26 ). 
         [0085]    Now that the side barriers  90 ,  92  and end barriers  70 ,  110  are in a folded position as seen in  FIG. 24 , the user can fold the front and rear trailer section  36 ,  32  to complete the compact state of the trailer  30 . The user may then access the taillight guard and grab handle  128  on the rear corner of the rear trailer section  36 . By lifting the rear trailer section  36  and its collected components (side barriers  90   c ,  92   c  and end barriers  110 ) utilizing the rear taillight guard grab handle  128 , a rotation of the rear trailer section  36  (as seen in  FIG. 25 ) on the rear side barrier hinges  103  will bring the rear trailer section  36  up and over 180-degrees to rest parallel and on top of the center trailer section  34 . In this state, all components are laying parallel to one another with very small clearance. The rear side barrier hinge  103  is used to rotate the rear trailer section  36  and its components onto the end of this moment arm  103   b  and the center trailer section  34  has an offset aperture point of rotation  105  that is above and over the rear trailer section  36 , but behind the part line  107 . 
         [0086]    The rear trailer section  36  is extended behind, and is attached below, the offset aperture point of rotational  105  of the rear translational side barrier hinge  109 . This causes the offset vertical  103   a  to act as a lever arm. At the end of this moment of the rear side barrier hinge  109 , is the attached rear trailer section  36 . While this moment arm allows the rear trailer section  36  and its components to be folded up and over the center trailer section  34  and its components, it serves a dual purpose in that when in the open position (see  FIG. 26 ), the weight of rear trailer section  36  and its components create a downward force normal to the moment arm, which keeps an applied force to the to the part line  107 , which works to stabilize the position of the section. This gravitational force helps keep the trailer in the open position without additional securing means. 
         [0087]    When rotating the rear trailer section  36 , and its components, the part line  107  makes a full rotation to the rested position on top of the center trailer section  34 , and its components. The part line surface  107   r  is a distance behind the original joined part line  107  of the rear side barrier hinge  109  in the open trailer position part line. Therefore, the rear trailer section  36  has translated backwards when in the folded position, thereby preventing the front bed section  32  and its components from striking when rotating upward on top in the compact/stored position as detailed above. Therefore, no locking is required of the folded rear trailer section  36  as is the case for the unfolded front and rear trailer sections  32 ,  34  because of the moment arms created by the offset vertical  102   b ,  103   b , and gravity working on the front and rear trailer sections  34 ,  36 . 
         [0088]    Removing the locking tongue spring pin  131  from its aperture, shown in  FIGS. 5 and 26  releases the front trailer section  32  from the elongated tongue  156 . Now trailer  30  is prepared for the folding process to configure the trailer  30  to a compact configuration. By accessing either front grab handle  78   a ,  78   b  and lifting the front trailer section  32  and rotating it about the front transitional side barrier hinge  108 , the front trailer section  32  is placed over and onto the previously folded rear trailer section  36  and its attached components. The front side barrier hinge  108  works in the same manner as the rear side barrier hinge  109  that extends higher above the front trailer section  32  and the center trailer section  34  to allow the front trailer section  32  and its collection of components of end barrier  70  and side barrier  90   a ,  90   b  to stack vertically and layered on top of the previously folded rear trailer section  36  and its components. Again, no locking is necessary at this stage as well, because of the importance of the sequence of folding and weight of the sections  32 ,  36  being folded utilizing gravitational force as a stabilizing mechanism. 
         [0089]    Thus, to place the trailer  30  in the compact configuration, the side barriers  90 ,  92  are folded down into a flat position; the end barriers  70 ,  110  are then folded down into a flat position; the rear trailer section  36  and its folded components are then rotated and positioned upon the center trailer section  34 ; and, the front trailer section  32  and its components are now rotated and positioned upon the rear trailer section  36  that is stacked upon the center trailer section  34 . In this compact configuration, the trailer  30  mat still be towed by a vehicle for transport of the trailer for one location to another (see  FIG. 26 ). 
         [0090]      FIG. 27  illustrates an embodiment of a folding vehicular utility trailer with the trailer sections in a stored configuration. To place the trailer  30  into this stored configuration, the trailer  30  is rotated from its towed position to a vertical position as displayed in  FIG. 27 . This is accomplished by removing the trailer  30  from any towing vehicles and lifting on the tongue  156 , which serves as a fulcrum lever for rotating upward. As the user begins to lift up on the elongated tongue  156  and/or tongue slide  155 , the folded trailer will rotate onto the caster stops  170  and the trailer tires, thereby holding the trailer in a balanced position at approximately 45-degrees to the ground. At this point, the trailer is resting in a transitional, stable position. Continued rotation of the trailer over the caster stops  170  will also place the trailer  30  additionally onto the front casters  172   a . The trailer is now in a stable, but still remains mobile with the center of gravity being relatively low in both in a horizontal and vertical orientation. As the rotation into the vertical position starts to occur, the low center of gravity helps the user rotate it up onto the casters stops  170  and the front and rear casters  171 ,  172 . As the rotation of the tongue  156  continues, the center of gravity progressively shifts rearward and downward, allowing it to easily be rotated onto the casters  171 ,  172 . Once the trailer is fully supported by the casters  171 ,  172 , this low center of gravity, along with the broad stance of the casters and their ability to roll freely, creates high inertia, making it very stable in the vertical stored position. This stability can be quantified utilizing the quantitative analysis found in  FIG. 19 . The computations for the stability in  FIG. 19  demonstrate the coupling effect of the low friction of the rolling casters  172  with the high force required to rotate (see  FIGS. 19 and 25 ). This analysis demonstrates the high stability of the trailer  30  in the vertical stowed configuration. 
         [0091]    The tongue  156  and tongue slide  158  may be rotated from its current twelve o&#39;clock (vertical) position by ninety-degrees to a three o&#39;clock or nine o&#39;clock stowed position (see  FIGS. 28 and 29 ). This then removes the fulcrum lever, which adds to the stability and collection of the stowed trailer. To rotate the tongue and tongue slide  155  back to the vertical position, it is rotated and locked into the saddles  154  and  162 , which then may engage  164  into the rear tongue slide locking tab  160 . The trailer  30  may easily be placed back in the horizontal position by reversing the aforementioned steps. 
         [0092]    The advantage of the previously mentioned operations is that the trailer components stay attached to the trailer and the components interlock. The trailer does not require side barriers or other components to be removed or stay fixed. Not only does it make for more efficient storage, but it improves the safety aspects by reducing the risk of components becoming detached or not being secured properly. 
         [0093]    The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.