Patent Abstract:
A trailer for use primarily for transporting a portable structure in which a frame is mounted on an undercarriage with the wheels of the undercarriage near the longitudinal center and the portable structure is positioned at an angle to reduce wind resistance while the structure is being transported on the trailer. The portable structure is secured to the trailer by placing the skid plates of the portable structure under frame elements affixed to the trailer frame.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority benefit from U.S. Provisional Application No. 61/330,575, filed on May 3, 2010, and is related to the following commonly-owned, co-pending U.S. patent application Ser. No. 1) 12/782,973, filed May 19, 2010, entitled “Fresh Flush Recycling Toilet;” 
     
    
     BACKGROUND 
       [0002]    This invention relates to the transport of portable structures, particularly portable toilets. Conventional portable or transportable structures such as portable toilet units are typically used at construction sites, outdoor public events and various other venues where a running water supply is unavailable. These structures generally comprise a housing within which a waste material storage tank is positioned. The housings of the portable toilet are usually made of large sheets of plastic materials which are formed into rear and side walls and a front wall having a doorway and a suitable door, a roof and a floor. The structures are typically light enough to be moved and/or loaded onto a trailer by one person who tips the structure down and slides it into place on the bed of a conventional flat bed trailer. 
         [0003]    It is desirable to transport portable toilet structures in an upright position to minimize the likelihood that waste will leak from the collection tank into the interior portion of the housing. Towing one or more portable toilet structures on a trailer presents challenges, particularly in windy conditions due to the shape of the structures and the wind resistance exerted against the housing walls as they are towed at normal driving speeds behind a truck or a car. While wind diverters and other devices have been conceived to help reduce wind resistance while towing using trailers, these devices are clumsy and must be mounted to the towing vehicle or the trailer. Examples of wind diverters can be found in U.S. Pat. No. 3,596,974 to Adams, U.S. Pat. No. 3,695,673 to Meadows and U.S. Pat. No. 3,768,854 to Johnson et al. 
         [0004]    Conventional flat bed and other trailer types are unsatisfactory or inconvenient to use for transporting portable toilet or other portable structures because there is no standardized element on a conventional trailer for quickly and easily securing the portable toilet structure to the conventional trailer. Also, the height or covered housing structure of a conventional trailer may make it difficult to load and unload the portable toilet structure. An example of a conventional flat bed trailer is disclosed in U.S. Pat. No. 3,731,831 to Huff. A standard trailer with a housing is disclosed in U.S. Pat. No. 4,807,894 to Walker. 
         [0005]    Specialty trailers for towing portable structures are also known. Examples of such trailers are disclosed in U.S. Pat. No. 7,401,804 to Rupp, U.S. Pat. No. 4,653,125 to Porter and U.S. Pat. No. 5,548,856 to Julian. 
         [0006]    It is desirable to provide a trailer for transporting one or more portable structures in which it is relatively quick and simple for a portable structure to be loaded onto, secured to and unloaded from a trailer. It is also desirable for the trailer to be designed such that the wind resistance incurred while towing the portable toilet structure at normal driving speeds, particularly on an interstate highway is reduced from the oncoming forward direction of the vehicle and for cross-winds from either side. The invention of the present application addresses these problems and provides an improved trailer for transporting portable structures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIGS. 1A-1D  show various views of a portable structure; 
           [0008]      FIG. 2A  and  FIG. 2B  show perspective views of a trailer for transporting a portable structure; 
           [0009]      FIG. 3  is a top down view of the trailer; 
           [0010]      FIGS. 4A-4B  are side views of the trailer; 
           [0011]      FIG. 5  is a rear view of the trailer; 
           [0012]      FIG. 6  is a top view of the trailer showing wind deflection direction as the trailer is being towed; and 
           [0013]      FIG. 7  is a top view of the trailer with a configuration to accommodate four portable structures. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]      FIGS. 1A-1D  show different views of a portable structure  10  where  FIG. 1A  is a perspective view,  FIG. 1B  is a front view,  FIG. 1C  is a side view, and  FIG. 1D  is a bottom view. Portable structure  10  has a hinged door  12  and a base  16  that is formed of horizontal skid plates  18  running from one side of structure  10  to the opposing side. 
         [0015]    As shown in the  FIGS. 2A-6 , a trailer  100  for transporting portable structure  10  includes a central axle  102  to which are affixed wheels  104  at either end, a tow bar  106 , a base frame  108 , a stabilizer bar  110 , a tow bar support  112 , a hitch  114  and fenders  116 . It should be understood that the function of tow bar support  112  can be alternatively achieved by integrating a support shape into tow bar  106  as shown in  FIGS. 2B and 4B . The height of the dip in the support shape may be configured for different uses and the drawings are not drawn to scale. For example, in the case of the trailer of the present invention, the dip in the support shape may be a few inches, or just enough to keep the hitch off the ground when the bottom of the support shape is resting on the ground. This configuration will prevent dirt or other debris from collecting in the hitch, but will not interfere with road topology where it is undesirable for the bottom of the support shape to drag on the ground while being towed. In other cases, the dip may be much more pronounced to raise the level of the hitch higher off the ground. The general purpose of the support shape is to eliminate the need for a jack stand (not shown) that is common on trailers of all types. 
         [0016]    A handle  113  may also be attached to the top of tow bar  106  to make it easier to lift tow bar  106  and place hitch  114  over the corresponding ball (not shown) extending from a vehicle. Base frame  108  holds the base of a portable structure by engaging one end of skid plates  18  formed at base  16  of portable structure  10 . Base frame  108  further includes a step bar  118 , bottom support members  120  that support the portable structure  10  underneath skid plates  18 , top skid plate engagement element  122  and securing rods  124 . Also attached to each of fenders  116  is a taillight cluster  126  housing taillights, brake lights and back-up lights that connect to the electrical system of the tow vehicle. 
         [0017]    The T-shaped trailer components consisting of axle  102  and tow bar  106  as well as fenders  116 , taillight clusters  126 , wheels  104 , hitch  114  and tow bar support member  112  will not be described in greater detail herein. Base frame  108  is mounted to the top of axle  102  and tow bar  106 . Base frame  108  is a rectangular or square shape that has dimensions slightly exceeding the base portion of portable structure  10 , including skid plates  18  that form base  16  of portable structure  10 . Each component of base frame  108  making up the four sides of base frame  108  is formed of an L-shape angled component  120  such that portable structure  10  comes into contact and sits atop the lower horizontal portion  120   a  of each L-shape angled component  120  with opposing ends of skid plates  18  contacting the vertical side portion  120   b  of L-shape angled component  120  at the both ends of each skid plate  18 . By having the dimensions of base frame  108  slightly exceed the dimensions of portable structure base  16 , portable structure  10  fits snugly inside of base frame  108  without shifting during transport. 
         [0018]    Base frame  108  is preferably mounted with a leading corner  128  affixed to tow bar  106 . Mounting can be accomplished by bolting base frame  108  to tow bar  106 , but is preferably accomplished by welding base frame  108  to tow bar  106  and axle  102 . Alternatively, it can be mounted through the use of permanent rivets or bolts and nuts. With lead corner  128  affixed to tow bar  106 , side corners  130  align with axle  102  inside of wheels  104 . Side corners  130  of base frame  108  are also preferably mounted to axle  102  by welding, rivets or bolts. Configuring base frame  108  with respect to axle  102  and tow bar  106  as described results in portable structure  10  sitting at a 45 degree angle to leading corner  128  bisected by an axis through tow bar  106 . This alignment results in natural wind flow deflection to the sides of portable structure  10 . The deflection occurs at a gentle 45 degree angle as the wind hits leading corner  128  and a corresponding corner of portable structure  10 . The wind then flows evenly and gently across the angled sidewalls of portable structure  10  affixed to trailer  100  as the portable structure  10  is towed on trailer  100  by a tow vehicle. The wind deflection is approximately equal on both sides and naturally stabilizes portable structure  10  during towing, particularly as compared to prior art designs where the wind hits the leading wall of portable structure  10  head-on resulting in a tendency to blow it over making trailers using such a design unstable and difficult to maneuver, particularly at highway speeds. 
         [0019]    In addition, the angled placement design of the present invention dictates that axle  102  be wider than that of a trailer for transporting a portable structure at a position angled 90 degrees to tow bar  106 . This is because the angled configuration must accommodate the diagonal dimension of a portable toilet structure which is greater than the side dimension of a portable structure  10 . The use of a wider axle  102  further increases the stability of trailer  100  resulting in better handling on the road. 
         [0020]    It should also be recognized that cross winds blowing from either side of trailer  100  will be broken at a 45 degree angle by side corners  130  in a manner similar to that described with respect to leading corner  128 . Wind resistance being directed from the front or side of the trailer during towing with the design of the present invention will be greatly reduced resulting in smoother operation for trailer  100  and a significant increase in the level of safety for the occupants of the vehicle towing trailer  100 , as well as others who may be occupants in vehicles on the road in the vicinity of trailer  100  during transport. 
         [0021]    In operation, portable structure  10  is loaded onto trailer  100  by tilting it and sliding the skids of the portable toilet structure up onto and over step bar  118  into base frame  108 . As can be seen in  FIGS. 1A-1D , Skid plates  18  on the bottom of portable structure  10  protrude beyond the walls of structure  10 . This protrusion of skid plates  18  provides a means for engaging portable structure  10  inside of base frame  108 . At one side of base frame  108  is a fixed skid plate engagement element  122 . The ends of skid plates  18  of portable structure  10  are positioned under plate  122 . Once base  16  of portable structure  10  is positioned in base frame  108  with skid plates  18  under plate  122 , the other end of skid plates  18  are secured at the opposing side of base frame  108  using securing rods  124 . These rods pass through anchor holes in skid plates  18  and through aligned holes in base frame  108 . The rods can be implemented in a number of ways including using screws, spring loaded rods or any other apparatus for holding skid plates  18  in place. Alternatively, a second fixed skid plate engagement element (not shown) can be locked down over the opposite ends of skid plates  18 . It is also possible to implement the second fixed skid plate engagement element using a spring loaded mechanism that can be easily and quickly opened during positioning of portable structure  10  and then locked over the ends of skid plates  18 . Once portable structure  10  is secured, it may be safely towed on trailer  100 . 
         [0022]    It is to be understood that the above descriptions and drawings are only for illustrating variations of the present invention and are not intended to limit the scope thereof. Any variation or derivation from the above description and drawings are included in the scope of the present invention. For example,  FIG. 7  shows a configuration of a trailer that can accommodate 4 portable structures. In such a configuration, the size of the underlying trailer frame could be made larger while maintaining the basic “diamond” shape. To accommodate the 3 additional portable structures, the opposing sides of the base frame could be lengthened to form an elongated rectangular base frame with the ability to hold two portable structures, while a second elongated base frame could be positioned adjacent to and behind the first base frame to accommodate two additional portable structures. In such a configuration, the trailer width and axle would need to be made at least as wide as the diagonal dimension of two portable structures. Additional elongated base frames could be added to a longer trailer to increase the number of portable structures to be carried.

Technology Classification (CPC): 1