Abstract:
A lightweight cargo carrying structure mounted upon arms which cantilever rearward from tow eyes mounted at the rear of a vehicle. This invention provides an efficient way to expand the cargo-carrying capacity of a vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of Provisional Patent Application No. 61/133,293 which was filed by the present inventor on Jun. 26, 2008. 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    None 
       SEQUENCE LISTING 
       [0003]    None 
       BACKGROUND OF THE INVENTION 
       [0004]    This invention relates generally to cargo carriers and more specifically to carriers which are mounted at the rear of a vehicle such as a car or truck. The carrier is supported by arms which engage tow eyes at the rear of the vehicle. These arms cantilever rearward to support a cargo enclosure, platform, rack or other cargo carrier. 
         [0005]    The prior art provides many options for transporting objects when storage space within a vehicle is not adequate or appropriate. Roof top carriers, trailers, cargo carriers attached to hitches, and carriers attached to either vehicle bumpers or vehicle channel members are all well known. Each of these have limitations which are overcome by embodiments shown below of the present invention. 
         [0006]    Roof top carriers significantly reduce the aerodynamic efficiency of the vehicle. Trailers are generally heavy; a significant number of vehicles&#39; warantees are voided if the driver tows a trailer. Cargo carriers attached to hitches may require the purchase and installation of a hitch and are subject to large moments about the hitch which necessitate a heavy structure which increases carrier cost and detracts from vehicle mileage and carrier payload. Carriers attached to vehicle bumpers (Carlson et al., U.S. Pat. No. 4,403,716) require structure no longer found on most vehicles. Some carriers (Godin, U.S. Pat. No. 5,033,662) require conveniently-located vehicle channel members for their attachment, members not available in most vehicles, and also require formation of an apperature in these channel members. 
         [0007]    Given these limitations, there is a need for a more efficient carrier which is lightweight, which saves fuel, which is easy to attach, and which is inexpensive to manufacture. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    There are presently shown in the drawings embodiments of the invention which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein: 
           [0009]      FIG. 1  is a perspective view of a cargo carrier of the present invention; 
           [0010]      FIG. 2  is an isometric exploded view of a cargo carrier of the present invention wherein portions of the carrier have been removed to reveal an arragement of carrier arm structure; 
           [0011]      FIG. 3  is a side view of a disposition of one embodiment of a carrier arm of the present invention relative to a tow eye with some elements omitted for clarity; 
           [0012]      FIG. 4  is a top view of a disposition of one embodiment of a carrier arm of the present invention relative to a tow eye with the tow eye and some elements of the carrier arm omitted for clarity; 
           [0013]      FIG. 5  is an isometric view of an embodiment of a cargo support means being an enclosure; 
           [0014]      FIG. 6  is a cutaway side view of a means by which a cargo enclosure may be supported on carrier arms; 
           [0015]      FIG. 7  is a perspective view of a cargo enclosure; 
           [0016]      FIG. 8  is a side view of a disposition of one embodiment of a carrier arm of the present invention relative to a tow eye with some elements of the carrier arm omitted for clarity; 
           [0017]      FIG. 9  is a perspective view of an embodiment of a cargo support means being a platform; 
           [0018]      FIG. 10  is a perspective view of an embodiment of a cargo support means being a cargo rack; and 
           [0019]      FIG. 11  is a perspective view of a disposition of one embodiment of a carrier arm of the present invention relative to a tow eye with some elements omitted for clarity; 
       
    
    
       [0020]    The below list summarizes the reference numbers and associated elements shown in above drawings:
     10  cargo carrier     11  cargo enclosure     12  carriage bolt     13  pin and clip assembly     14  drawer lock     15  rigid panel     18  hinge     19  gasket     20  flush fit handle     21  wood corner brace     22  cantilever arm assembly     22 ′ cantilever arm assembly     23  lift support     26  outboard cantilever arm     26 ′ outboard cantilever arm     27  bearing plate     27 ′ bearing plate     28  primary bolt     29  high strength bearing bolt     30  leg     31  bottom exterior sheathing     32  flexible bumper     33  sacrificial adapter     34  spacer     35  tow eye     36  red reflector     37  amber reflector     39  cantilever arm primary hole     40  fender washer     41  bushing     41 ′ lightweight bushing     42  bushing retaining nut     43  concave washer     44  stop nut     45  adjustment screw     46  adjustment nut     47  weld     47 ′ weld     48  locking nut     49  bearing plate retainer     50  tow eye hole     51  fender washer     52  mandrel half     53  mandrel bolt     54  mandrel nut     55  primary nut     56  cargo platform assembly     57  cargo rack assembly     58  tumbuckle assembly     59  washer     60  top wall     61  bottom wall     62  encircling side wall     63  inboard cantilever arm     63 ′ inboard cantilever arm     64  pin and locking end assembly     65  strike plate     66  leg assembly   
 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0079]    A first embodiment of a lightweight cargo carrier for vehicles  10  is shown in a perspective view in  FIG. 1 . The lightweight cargo carrier for vehicles  10  is shown with a cargo support means consisting of cargo enclosure  11  having a top wall  60 , an encircling side wall  62 , and a bottom wall  61  which is not shown in this view. A plurality of cantilever arms  22  is shown supporting cargo enclosure  11 . The vehicle end of the cantilever arms  22  is not visible in this view. 
         [0080]    The primary attachment means are shown as primary bolts  28  in  FIG. 2  which view includes an exploded view of cantilever arm assembly  22 . In this embodiment, inboard cantilever arm  63  telescopically engages outboard cantilever arm  26  and these two members are secured by a securing means consisting of a pin and clip assembly  13 . Mandrel halves  52  acting in concert with inboard cantilever arm  63  define a generally cylindrical form with which to engage the end of outboard cantilever arm  26 . 
         [0081]    Bottom wall  61 , visible in  FIG. 2 , is supported by two cantilever arm assemblies  22 . Top wall  60 , bottom wall  61  and encircling side wall  62  may be constructed of any strong, durable, sturdy, material. In one embodiment, these components are constructed of plywood, wood, aluminum sheet metal, and steel sheet metal. A durable plastic material, a composite material, or a lightweight metal such as aluminum or titanium could also be used to construct these components. 
         [0082]    In the embodiment shown in  FIG. 2 , inboard cantilever arms are made of steel plate and the outboard cantilever arms are constructed of tubular steel. Other embodiments could be made of other strong and durable materials including without limitation titanium or a composite material. Other embodiments could be made entirely of tubular steel appropriately bent and flattened as shown in  FIG. 11 . 
         [0083]    Adjustment means permitting modification of the angle of pitch of cantilever arms with respect to vehicle are demonstrated by adjustment screw  45 , adjustment nut  46 , bearing plate  27 , and locking nut  48  in the embodiment shown in  FIG. 3 . The bearing plate  27  engages tow eye  35  at a point forward of the cantilever arm primary hole  39 . The forward end of inboard cantilever arm  63  is machined to accept adjustment nut  46  so as to align the axis of adjustment nut  46  to be substantially aligned with the center plane of inboard cantilever arm  63 . This embodiment shows adjustment nut  46  and inboard cantilever arm  63  fastened securely by weld  47 . Bearing plate  27  is retained between inboard cantilever arm  63  and fender washer  51  by bearing plate retainer  49  which is secured to inboard cantilever arm  63  by weld  47 ′. This adjustment means is shortened or lengthened by the turning of adjustment screw  45 . The present embodiment constructs adjustment screw  45 , adjustment nut  46 , bearing plate  27 , and locking nut  48  of steel but these may be constructed of other similarly strong and durable materials. Mandrel halves  52 , shown in  FIG. 3 , each posses a pair of annular projections which engage holes in the corresponding face of inboard cantilever arm  63 . Mandrel bolt  53  and mandrel nut  54  work to retain mandrel halves  52  in proper alignment with inboard cantilever arm  63 . In these embodiments, mandrel halves  52  are constructed of steel but could be constructed of any suitable material including iron, titanium or a composite material. 
         [0084]    The cargo enclosure shown in  FIG. 5  has a hollow interior. Also in  FIG. 5 , top wall  60  is connected to encircling side wall  62  by hinge  18  which is shown as a piano-style hinge though other embodiments could use other types of hinges such as multiple separate hinges or hinges constructed of a flexible material such as neoprene or heavy fabric. In one embodiment of the present invention lift support  23  retains top wall  60  is a substantially vertical position. In one embodiment of the present invention adjoining walls of a cargo enclosure are connected by a wood corner brace  21  to which both adjoining wall panels are glued and fastened with screws. 
         [0085]    In one embodiment drawer locks  14  secure access to the cargo enclosure  11 . In this embodiment the locks employed are lock sets marketed as drawer locks though they could be constructed with any suitable lock including many locks marketed as trailer door locks. 
         [0086]    A leg  30  supporting a cargo enclosure  11  and supported in turn by cantilever arm assembly  22  is shown in  FIG. 6 . A plurality of bushings  41  keep carriage bolt  12  coaxial with leg  30 . Bushing retaining nut  42  serves to hold the top bushing in place while stop nut  44  holds the cargo carrier  11  and the leg  30  to cantilever arm assembly  22 . All of the components of the leg assembly  66  except lightweight bushings  41 ′ are of steel in the embodiment shown though the could be made of any suitably tough and durable material. Leg  30  and concave washer  43  are formed of tubular steel by means of cutting with a hole saw. Lightweight bushings  41 ′ are of plywood in this embodiment but could be of any material suitably light and rigid such as a plastic material. 
         [0087]    In the embodiment shown in  FIG. 6  a rigid panel  15  comprises a bottom wall  61  being constructed of plywood. Bottom wall  61  is protected from damage by bottom exterior sheathing  31  which in this embodiment is sheet steel, though it could be of other similarly tough and durable materials such as sheet aluminum or sheet stainless steel. 
         [0088]      FIG. 7  shows flush fit handles  20  in one embodiment of the present invention. These are constructed of steel but could be of any suitably rigid and durable material such as aluminum. Also shown in  FIG. 7  are flexible bumpers  32 . These are composed of sheet vinyl in the present embodiment but could be constructed of any suitably flexible and durable material such as rubber. 
         [0089]      FIG. 8  shows a structural element in tension as a means to adjustably connect the cargo carrier to the vehicle in order to allow modification of the angle of pitch of the cantilever arm with respect to the vehicle. In this embodiment the structural element, tumbuckle assembly  58 , engages the carrier at a point aft of the primary attachment means which is the primary bolt  28 . In addition, the structural element, turnbuckle assembly  58 , engages the vehicle at a point above the primary attachment means. In this embodiment the tension element is constructed of a tumbuckle of high strength steel though a tumbuckle could be constructed of any suitably strong and durable material. Other embodiments could attach to other elements of the vehicle structure for example vehicle channels, spare tire support structure, or bumper support structure. Other embodiments could be constructed of another type of structural element in tension, for instance a rope and pulley assembly, a cable and winch assembly or webbing with a ratchet. 
         [0090]    A cargo carrier of the present invention wherein the cargo support means is a platform is shown in  FIG. 9 . In the embodiment shown the platform surface is constructed of heavy duty welded wire hardware cloth, but other embodiments could be constructed of any other similarly strong and durable materials. For example, the platform surface could be constructed of diamond plate metal sheet. 
         [0091]      FIG. 10  shows a cargo carrier of the present invention wherein the cargo support means is a rack. In the embodiment shown the rack is disposed to carry bicycles. Other embodiments could be constructed to carry other large objects. For example, a rack could be built to carry skis. The embodiment shown is constructed of tubular steel which has been bent, cut, and welded. Other embodiments could be constructed of any suitably light and durable material such as aluminum, titanium or a composite material. 
         [0092]      FIG. 11  shows an embodiment of the present invention in which an inboard cantilever arm  63 ′ is constructed entirely of tubular steel. In this embodiment the tube is bent and the forward end of the tube is flattened over a form the same thickness as tow eye  35  and is then cut and drilled to receive tow eye  35 , primary bolt  28 , and high strength bearing bolt  29 . In this embodiment bearing plate  27 ′ is triangular and has a hole drilled in it through which passes high strength bearing bolt  29 . Bearing plate  27 ′ is the same thickness as tow eye  35  and is held substantially within inboard cantilever arm  63 ′. Sacrificial adapted  33  is composed of a relatively softer steel than tow eye  35  and is conformed to the generally irregular face of tow eye  35  by the application of pressure. After sacrificial adapter  33  has been conformed to tow eye  35  a spacer  34  is selected of the appropriate thickness to set cantilever arm assembly  22 ′ to the appropriate pitch with respect to the vehicle. Spacer  34  is bent at both ends to secure it around bearing plate  27 ′ and within inboard cantilever arm  63 ′. Inboard end of outboard cantilever arm  26 ′ is swaged to a slightly larger diameter to permit telescopic engagement with inboard cantilever arm  63 ′. The embodiment shown is constructed of tubular steel. Other embodiments could be constructed of any suitably strong and durable material such titanium. 
         [0093]      FIG. 11  also shows a cargo carrier of the present invention which has a cantilever arm assembly secured with a lockable securing means. In this embodiment, inboard cantilever arm  63  is fixedly attached to outboard cantilever arm  26  by means of pin and locking end assembly  64 . 
         [0094]    In operation, lightweight cargo carrier  10  may be carried behind a car or truck without need for a hitch by engaging tow eyes at the vehicle rear. As the vehicle moves, airflow is minimally disrupted by the presence of cargo carrier  10  resulting in a minimal reduction in fuel efficiency while carrying cargo. Vehicle loads are reduced by the efficiency of not needing a hitch to carry a load, resulting in further operational efficiencies accruing to vehicles employing a cargo carrier  10 , efficiencies realized when traveling both with, and without, a cargo. One embodiment of the present invention can carry bicycles upon a rack assembly  57  at a sufficient distance rearward to permit easy opening of a rear vehicle hatch, the multiple arms being so disposed as to greatly reduce angular moment normally imposed on the carrier elements by such rearward offset of a hitch-based carrier. The operation of attaching a cargo carrier  10  of the present invention is relatively inexpensive and easy since there is no need to purchase a hitch. Finally, the use of a cargo carrier  10  makes possible cargo carrying operations by smaller vehicles for which in the past there were limited cargo options. 
         [0095]    While exemplary systems and methods embodying the present invention are shown by way of example, it should be understood that the invention is not limited to these embodiments. Modifications can be made by those highly skilled in the art, particularly in light of the foregoing teachings. For example, each of the elements of the aforementioned embodiments may be utilized alone or in combination with elements of other embodiments.