Abstract:
A simple and lightweight solution to the storage and delivery of dry flowable materials that is cost-effective, can be standardized to facilitate transportation and isolates the materials from exposure to air, insects and other contaminants. An apparatus includes a vessel and a delivery assembly, having a rotary feeder that upon gravity discharge of the dry flowable material moves such material to a desired location.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of and priority from U.S. application Ser. No. 62/296,343, filed Feb. 17, 2016, which is hereby fully incorporated herein by reference. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    This disclosure relates to an apparatus for storage and delivery of dry flowable materials. More particularly, this disclosure relates to an apparatus including an hopper assembly configured either as a frame supporting a vessel that stores and facilitates transport of dry flowable materials that fits within a volume defined by a standard sized intermodal container or a trailer having a vessel that stores and facilitates transport of dry flowable materials, and a delivery assembly configured to pneumatically convey the dry flowable materials from the vessel, without pressurizing the hopper vessel. 
       BACKGROUND 
       [0003]    Conventionally, dry flowable materials, such as granular chemicals or plastics, polymers, agricultural products, mineral products, etc., are moved in bulk form from a manufacturing facility or a distribution center to an end user by a trailer that has been manufactured as a pressure vessel. For example, see a conventional trailer illustrated in  FIG. 1 . 
         [0004]    In order to deliver or unload the materials, air pressure in the range of 3-15 pounds per square inch (psi) is applied to the vessel on top of the materials. The pressure differential enables materials to be discharged from the pipe that connects the cones on the bottom of the trailer. As a result, at least one person is required to monitor the trailer pressure and to operate the trailer valves during the delivery process. Another disadvantage is that the conventional trailer, since it is configured as a pressure vessel, is reinforced, heavy and expensive. Consequently, the total payload capacity for the dry flowable material is reduced. 
         [0005]    Alternately, conventional vehicles such as a dump truck or dump trailer may facilitate movement of dry flowable materials to a delivery point. However, such vehicles do not prevent exposure of the materials to air, insects or other contaminants during storage or transportation. Additionally, such vehicles cannot and do not provide any of the advantages of the apparatus disclosed herein. 
         [0006]    Therefore, there is a need in the art for a simple and lightweight solution to facilitate the storage, transport and delivery of dry flowable materials that is cost-effective, standardized and that overcomes the disadvantages of the complex, lacking and costly prior art systems. 
         [0007]    This disclosure consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated. 
           [0009]      FIG. 1  illustrates a conventional trailer for dry flowable materials. 
           [0010]      FIG. 2  illustrates a side elevation view with a partial cross section view of one embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure. 
           [0011]      FIG. 3  illustrates a perspective view of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure. 
           [0012]      FIG. 4  illustrates a side elevation view of the apparatus of  FIG. 3 . 
           [0013]      FIG. 5  is an end elevation view with a partial cross section view of the apparatus of  FIG. 2 . 
           [0014]      FIG. 6  is an end elevation view of the apparatus of  FIG. 3 . 
           [0015]      FIG. 7  illustrates a rotary valve configured to facilitate delivery operation of the dry flowable product in accordance with the present disclosure. 
           [0016]      FIG. 8  illustrates a side elevation view of another embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure. 
           [0017]      FIG. 9  illustrates a side elevation view of another embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure. 
           [0018]      FIG. 10  illustrates another side elevation view of the apparatus of  FIG. 9 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    The following disclosure as a whole may be best understood by reference to the provided detailed description when read in conjunction with the accompanying drawings, drawing description, abstract, background, field of the disclosure, and associated headings. Identical reference numerals when found on different figures identify the same elements or a functionally equivalent element. The elements listed in the abstract are not referenced but nevertheless refer by association to the elements of the detailed description and associated disclosure. 
         [0020]      FIGS. 2 and 5  illustrate one embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure that is configured to have outside dimensions that fit within a volume defined by a standard sized intermodal container and includes a vessel for the storage and transport of dry flowable materials. A complementary delivery assembly is configured to couple to the vessel and pneumatically convey the dry flowable materials out of the vessel without pressurizing the container, as described herein. 
         [0021]      FIGS. 3, 4 and 6  each illustrate view of another embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure that is configured to have outside dimensions that fit within a volume defined by a standard sized intermodal container and includes a vessel and complementary delivery assembly configured to couple to the vessel and pneumatically convey the dry flowable materials out of the vessel without pressurizing the container, as described herein. 
         [0022]    An intermodal container is a shipping container having standardized dimensions (i.e., International Standards Organization ISO 668) that are designed and built for freight transport regardless of the means, i.e., these containers are adapted to be used across different modes of transport—from ship to rail to intermodal chassis—without unloading and reloading their cargo by having standardized corners to facilitate connection to one another or a chassis (i.e., International Standards Organization ISO 1161). Intermodal containers are primarily used to store and transport materials and products efficiently and securely in the global containerized intermodal freight transport system. Ninety percent of the global container fleet are so-called “dry freight” or “general purpose” containers that are configured as durable closed steel boxes, in certain standard lengths, mostly either twenty, forty or fifty three foot (6, 12 or 16 meters) in length. A standardized shape is beneficial for reasons set forth above. However, the standardized shape represents a bare rectangular volume with doors on an end. These containers can store and transport dry flowable materials, but the only way the container can be emptied is to have the necessary equipment to tilt the container or stand it up on its end. Consequently, to only way to make deliveries directly to a customer facility with a conventional intermodal container requires a giant plastic bag installed in the container which is then filled with the product. A specialized tilt chassis and/or tractor mounted lift system is also required which is heavy, expensive and unable to be used if the customer unloading are is not completely flat. 
         [0023]      FIG. 8  illustrates another embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure that is configured as a trailer including a frame having a wheel and tire assembly, where a vessel is connected to and supported by the frame. A complementary delivery assembly is configured to couple to the vessel and pneumatically convey the dry flowable materials out of the vessel without pressurizing the container, as described herein. 
         [0024]      FIGS. 9 and 10  illustrate another embodiment of an apparatus for transportation, storage and delivery for dry flowable product in accordance with this disclosure that is configured as a trailer including a partial frame pivotally connected to a vessel that is configured as a stressed member and to which a wheel and tire assembly is connected. A lift cylinder or column is connected to the frame and vessel and a complementary delivery assembly is configured to couple to the vessel and pneumatically convey the dry flowable materials out of the vessel without pressurizing the container, as described herein. 
         [0025]    In the present disclosure, the apparatus  100  includes a vessel  103 ,  203 ,  303 , that may have a substantially hopper  101  or cylindrical  301  configuration, and frame  102  supporting a vessel  103  for the storage, transport and delivery of dry flowable materials. In certain embodiments, the apparatus  100  fits within a volume defined by a standard sized intermodal container (as shown in  FIGS. 2-6 , i.e., ISO 668), and in others the frame is configured as what is more commonly understood to be referred to as a trailer  200 , where the frame  200 ,  300  is connected to and supports the vessel  203 ,  303  and includes a wheel and tire assembly  211 ,  311  (as shown in  FIGS. 8-10 ). A delivery assembly as shown in  FIG. 7 , is configured to pneumatically or hydraulically convey the dry flowable materials from the vessel  103 ,  203 ,  303 , without pressurizing the vessel  103 ,  203 ,  303 . 
         [0026]    In the embodiment shown in  FIGS. 2 and 5 , the apparatus  100  includes a vessel  103  that is configured substantially as a hopper  101 , and a frame  102 . The outer or exterior dimensions of the frame  102  define top and bottom planes, end planes disposed normal (or perpendicular) to the top and bottom planes and side planes disposed normal to the end planes. The frame  102  also may have exterior side, end, and bottom panels  105  connected thereto to fully enclose the vessel  103  such that the apparatus  100  is configured to have outer dimensions that fit within the envelope of a standard intermodal container as per ISO 668, for example only 40 feet—8.85 feet—7.7 feet as shown. One of skill in the art will recognize that other standardized dimensions may be successfully used in connection with this disclosure as per ISO  668 . The standardized dimensions and strength requirements facilitate movement of the apparatus through the intermodal industry, e.g., ship, rail and trucking, since it will fit in a standard intermodal stacking, crane fixtures, chassis and railcar. Preferably, the frame  102  may also include standard intermodal corner castings in compliance with ISO 1161 at each corner to facilitate connection with standard container lift systems, fixtures, mounting connectors, etc. and fitment to an intermodal container chassis for transport by a tow vehicle. In one embodiment, the apparatus  100  may include substantially conventional side and end walls, such that from all outward appearances the apparatus  100  is a standard intermodal container. Other embodiments of this apparatus  100  may be, for example only, 20, 48 and 53 foot length options. 
         [0027]    In another embodiment, for example in  FIGS. 3, 4 and 6 , the apparatus  100  may include no exterior side, end or bottom panels where the frame  102  is configured with corner castings  130 , side rails  131 , end rails  132 , corner posts  133 , headers  131 , sills  131 , etc. to function as an exoskeleton of connected castings and tubing to protect the vessel  103  disposed therein. 
         [0028]    The vessel  103 , in either of the embodiments identified above, may include top, bottom (or inclined interior) and/or side walls  104 ,  114 ,  117  that define an enclosed volume of approximately 1500-1650 cubic feet for the dry flowable material. Preferably, the top wall  104  is parallel to the top plane, the side walls  117 , disposed between the top  104  and bottom  114  walls, are parallel to the side planes, and the bottom walls  114  are disposed at an angle with respect to the bottom and top planes. End walls  119  may also be disposed between the top  104  and bottom  114  walls parallel to the end planes. 
         [0029]    The bottom walls  114  are inclined to with respect to the bottom panel  105  in order to funnel the dry flowable material to cooperatively define an opening disposed at a lowermost extent of a plurality of the bottom walls  114  so that the dry flowable material may be discharged or delivered from the vessel  103 . The openings preferably have a valve  112  (see  FIG. 2 , which is the same as set forth in  FIGS. 3, 4 and 6 , and may include a plurality of valves  112 ) configured as a slide gate, butterfly or hopper valve or the like, etc. connected to the plurality of adjacent the inclined bottom interior walls  114  about and aligned in registration with the opening to seal the opening from unintended release of any of the dry flowable product when in storage or transportation configurations. Preferably, the valve  112  is selectively operable between open and closed orientations. The valve  112  may be configured to facilitate a positive, sealed or limited leakage connection with a delivery assembly that is configured to pneumatically convey the dry flowable materials from the vessel, without pressurizing the hopper vessel  103 . Preferably, the bottom walls  114  are inclined between 35-60 degrees with respect to the horizontal plane or bottom panel  105 . In one embodiment, two valves  112  are used where there is a pair of sets of inclined interior walls  114 , each associated with one of the pair of sets of inclined walls  114 . Additionally, as shown in  FIG. 5 , further inclined interior bottom walls  114  extend from the side walls to the valve  112  that are similarly inclined, such as from the ends of vessel  103 . 
         [0030]    The top wall  104  preferably includes openings so that the vessel  103  can be easily filled with the dry flowable product and a suitable cover for such openings is also preferred. For example only, dome lids  108  that are pivotally connected to the top wall  104  permit (i.e., open orientation) and restrict (i.e., closed orientation) access to an opening formed in the top wall  104  under the lid  108 . A rupture disk  110  may also be provided as a safety measure to prevent the build-up of unwanted pressure within the vessel  103 . Further, a filtration assembly  140  may be included to assist with the buildup of unwanted pressure, but also to filter ambient air entering and leaving the vessel  103 , primarily in order to prevent the dry flowable material from being contaminated. 
         [0031]    In the embodiments shown in  FIGS. 2-6 , the tow vehicle, truck, tractor or prime mover is commonly a basic vehicle used in the transportation of containers between and among intermodal facilities and is not considered or appropriate for over-the-road or long distance duties. Accordingly, such vehicles have not only fewer driver amenities, but also reduced functionality in comparison to over-the-road trucks. The delivery assembly  400 , as shown in  FIG. 7 , preferably includes a rotary valve or feeder  401  or other similar device or assembly having an inlet that is configured to align in registration with the valve  112  to facilitate unrestricted movement of the dry flowable material from the vessel  103 , through the valve  112  into the rotary feeder  401 . The delivery assembly also includes a discharge plenum  405  connected to an outlet of the rotary valve  401  that includes a discharge port  402  and an air inlet port  406 , a discharge, delivery or unload hose (not shown for simplicity, but commonly understood, by one of skill in the art, and configured for connection to the discharge port  402  or the air inlet port  406  if a series of rotary valves  401  are used), and an air conveyance hose (not shown for simplicity, but understood by one of skill in the art upon further description below and configured for connection to the air inlet port  406  or at least one air inlet port  406  in the event a series of rotary valves  401  are used). Preferably, the delivery assembly  400  would be available at the delivery location so that it can be attached to the apparatus  100  upon arrival for discharge of the dry flowable material into the storage facilities of the delivery point. Alternatively, dedicated trucks can carry the delivery assembly  400  on-board. 
         [0032]    The rotary feeders  401  may function either by electrical, pneumatic or hydraulic actuation  404 . Cable or hose  407  connects to the actuator  404  to functionally activate the rotary feeder  401 . For example, hose  407  may connect at an opposite end to a power take-off that provides pressurized hydraulic fluid from a tow vehicle, truck, tractor or other prime mover on-board system or a compressor that provides pressurized air from an on-board system. Alternatively, the cable  407  may connect at an opposite end an electrical source. However, most trucks that move the apparatus  100  as shown in  FIGS. 2-6  usually do not generate enough electrical power to adequately actuate a rotary valve necessary to convey, discharge or deliver the dry flowable materials, and, for safety reasons, there is usually not an electrical outlet (or an outlet with sufficient load capacity) anywhere near where the dry flowable materials are unloaded, delivered, etc. Thus, electrical actuation in connection with the apparatus of the present disclosure has significant disadvantages. Additionally, such intermodal trucks also do not have hydraulic “wet kits” which are heavy and messy to operate and clean up or which would be anywhere near sufficient for the operation of a rotary feeder  401  much less a series of rotary feeders  401 . 
         [0033]    The present disclosure proposes, for the embodiments shown in  FIGS. 2-6 , a plurality of small rotary valves  401  that are commonly pneumatically operated by a pressurized air system found on nearly every truck. Modifications to the air system are minimal, in that a tap to connect a pressurized air source, such as the air compressor outlet of the pressurized air storage tank is all that is required. Rotary valves pneumatically operated by pressurized air can be smaller and lighter, and thereby easier to install and remove. By configuring multiple rotary valves in-line, the system will provide the discharge capacity of a much larger valve. Additionally, the plenum  405  facilitates connected of the plurality of valves  401  to a common discharge (i.e., in series with one another) with at least one air inlet  406  connected to the pressurized air source or a blower found at a delivery site, which functions as a secondary pressurized air source that facilitates movement of the dry flowable product from the rotary valves  401  to the storage location, silo, compartment, etc. or the like since the blower can provide a greater volume of air necessary in order to provide in intended functionality. 
         [0034]    The unloading system of valves and pipping is easily removable from the apparatus  100  since the apparatus  100  must be fitted to an intermodal container chassis in order to be mobile. The unloading delivery assembly system is preferably installed on the vessel before shipment thereof to the recipient, or at the recipient&#39;s facility, and may be removed from the apparatus after the delivery is made. A delivery assembly  400  including a pneumatically operated rotary valve  401  is connected to each valve  112  and then connected to a single discharge or unload line, hose, conduit, etc. at the discharge port  402 , which may connect to an inlet port  406  of an adjacent rotary valve  401  in series. The operator then connects a hose at one end to a source of pressurized air, that is either stationary at the customer, recipient, delivery location, or on the tow vehicle to the air inlet port  406  of each valve  401 , but more likely to at least one valve  401  if there is a series of valves  401 , and actuates the air source to move air through the discharge or unload line, hose, conduit, etc. The pressurized air from the air source carries the product from the rotary valve  401  into the storage location. The operator then confirms that the air source hose (either stationary or on the tow vehicle) is connected to each rotary valve  401  and that the air source is activated in order to actuate the rotary valves  401 . The valves  112  are then moved to the open orientation and, after the valve  112  is opened, the dry flowable materials will flow into the top of the pneumatically operative rotary valve  400  by gravity and be moved into the discharge hose via port  402  for delivery to its intended unload location. Usually, the dry flowable material is discharged from the hopper  101  only when at a delivery location, where in such instance the hopper  101  will be secured to a chassis that is configured to mount standard intermodal containers. 
         [0035]    The delivery assembly  400  may be carried on the chassis onto which the apparatus  100  is mounted, the tow vehicle that pulls the chassis or stored at the delivery location depending on the volume of dry flowable material that is delivered to such location on a periodic basis, customer preference, etc. However, since the enclosed volume of the vessel  103  is not pressurized, and is in fact vented to atmosphere, the unloading, discharge or delivery of the dry flowable materials within the vessel  103  is not required to be monitored by at least one person and can occur without any supervision after the delivery assembly is properly connected and activated. After the vessel  103  is emptied, the operator will close the valves  112 , de-activate the rotary valves  400  (i.e., remove or disconnect the source of pressurized air), stop and disconnect the air source, the delivery assembly may be disconnected from the vessel  103  at this time, or at another time. 
         [0036]    As will be recognized from  FIG. 8 , in another embodiment the apparatus  100  may be configured to include a trailer that includes a frame  200  (shown only in partial schematic representation to avoid confusion and for simplicity, but would be commonly understood by one of skill in the art based upon the description herein), that includes structure (e.g., tongue, tow bar, king pin, etc.) to facilitate connection of the trailer to a truck or other prime mover, structure to mount a load bearing wheel and tire assembly  211 , and a vessel  203 , configured substantially as a hopper  101  similar as shown in  FIGS. 2-6 , for the dry flowable material substantially as described as above. 
         [0037]    This embodiment is similar in concept to the prior embodiment of  FIGS. 2-6 , except it is not constrained by the standardized dimensions of an intermodal container and does not use the various castings, tubing, exoskeleton, side, end and bottom walls found in the prior embodiment. Accordingly, the enclosed volume can be greater (e.g. approximately 1500-2000 cubic feet) when the dimensions of the enclosed volume are approximately 36 feet long×8 feet wide×12 feet high. Basically, the structure of the trailer  200  is provided only to support the vessel  203  which enables a very lightweight construction, including, but not limited to the use of aluminum, polymers and other materials of the like, etc. One of skill in the art will recognize that the dimensions of this embodiment may be adjusted to facilitate the intended functionality, perhaps only limited by the federal, state, or local laws, rules and regulations directed to size of vehicles that travel upon roadways, including but not limited to any requirements for size and strength administered by the US Department of Transportation, Transport Canada, Transportation Safety Board of Canada, Secretaria de Comunicaciones y Transportes (SCT) [Ministry of Communications and Transportation in Mexico], Dirección General de Autotransporte Federal (DGAF) [General Directorate of Federal Motor Carriers in Mexico], or any other similar or related requirement or entity. 
         [0038]    A top wall  204  must include openings so that the vessel  203  can be filled with the dry flowable product and a suitable cover for such openings is also preferred. For example only, dome lids  208  that are pivotally connected to the top wall  204  permit and prevent access to an opening formed in the top wall  204 . A rupture disk  210  may also be provided as a safety measure to prevent the build-up of unwanted pressure within the apparatus  100 . 
         [0039]    Side, end and intermediate walls  250 ,  252  and  254  are configured substantially the same as a hopper  101  as shown in the prior embodiment to define the vessel  203 . However, in one embodiment a preferred angle of inclination of 45-65 degrees may be provided to funnel the dry flowable materials into the valves  212  (which are similar configured as otherwise described herein). Preferable, in every embodiment, the valves  212  are disposed at least 18 inches above a reference ground surface and configured to couple to the delivery assembly as described otherwise herein. 
         [0040]    The delivery assembly  400  and the associated loading and unloading process is the same as described above and will not be repeated for the sake of brevity, but all of the advantages are equally applicable in this embodiment. 
         [0041]    As will be further recognized in  FIGS. 9 and 10 , in another embodiment the apparatus  100  may be configured substantially as a trailer that includes a partial frame  300  that is pivotally connected to the vessel  303  near a mid-point  305  thereof and has a connection block  301  at an opposite end to facilitate selective connection to a tow vehicle, truck or other prime mover (such as a king pin) and a bulkhead  307  connected to an adjacent end of the vessel  303  that also facilitates raising or lifting of such end of the vessel  303  (as shown in  FIG. 10 ), structure  309  for an articulable mounting of a load bearing wheel and tire assembly  311  to the vessel  303 , and the vessel  303  for the dry flowable material substantially as described as above but preferably more cylindrical for a substantial portion of its length and constructed so as to function as a stressed member able to support the weight of its structure, the dry flowable contents, and the associated components of the trailer and including a rear section  313  disposed adjacent the wheel and tire assembly  311  that smoothly transitions from the generally cylindrical configuration to an interface with an installed rotary valve  400  (substantially as described with respect to  FIG. 7 ) and functions substantially as a funnel, i.e., tapering so as to reduce cross-sectional area as the vessel  303  transitions to the opening for the rotary valve  300 , as shown in  FIG. 10 . 
         [0042]    The bulkhead  307  may include an extendible lift column  310  that may be multi-segmented or include a number of nesting components where the bottom or innermost component  312  is movably connected to the mounting block  301  at the end  315  of the frame  300  opposite the mid-point  305  and the top or outermost component  314  is movably connected to the bulkhead  307  by a trunnion or pivot point  317 . The column  310  may be actuated by hydraulic (preferable), electric, air or similar know functionality to facilitate the intended purpose of extending the column so that as a result the vessel  303  is raised, preferably in the range of 30-50 degrees, so that the dry flowable product is moved be gravity to the rotary valve  401  installed on the structure  309  for discharge to a storage location, such as a silo. Preferably, as described generally above, the lift column  301  and rotary feeder  401  are coupled by a hose to a pressurized hydraulic source in order to actuate such devices to perform the intended functionality. 
         [0043]    Aerators  319  that are connected to a source of pressurized air may be provided on a bottom of the vessel  303  so that the dry flowable material can be fluidized during delivery and discharge so as to enhance movement of the material when the column  310  is extended, much in the way that the dome lids  308  or a filtration assembly  340  may be openable to atmosphere in other or this embodiment. The hose connected to the pressurized air source is also coupled to the air inlet port of the delivery assembly as described herein. 
         [0044]    The loading process is the same as described above and will not be repeated for the sake of brevity, but all of the advantages are equally applicable in this embodiment. The unloading process is slightly different as alluded to and mentioned above. Since the unloading delivery assembly  400  is installed with the vessel  303 , i.e., a hydraulically operated (or other power sourced) rotary valve  401  is connected to the transition  313 , a single discharge or unload line, hose, conduit, etc. may be connected at the discharge port  402  of the rotary valve  401  to move the materials from the vessel to a desired location. Preferably, the operator confirms that a pressurized air source (either stationary at the customer, recipient, delivery location, or on the tow vehicle) is connected to the aerators and the air inlet port  406 , and actuates the air source to move air through the discharge or unload line, hose, conduit, etc. and the aerators  319 . Preferably, the operator confirms that a pressurized hydraulic source (either stationary at the customer, recipient, delivery location, or on the tow vehicle) is connected to the lift column  310  and rotary feeder  401 . The pressurized hydraulic source is actuated so that the column  310  is moved from a retracted orientation to an extended orientation to facilitate a gravity feed of the dry flowable product into the rotary feeder  401 , which is then discharged into the plenum and air carries the product into the storage location. The structure  309  is connected to the wheel and tire assembly  311  so as to permit articulation such that all 8 tires of the wheel and tire assembly remain on the ground for stability. 
         [0045]    The above detailed description and the examples described therein have been presented for the purposes of illustration and description only and not by limitation. It is therefore contemplated that the present disclosure cover any and all modifications, variations or equivalents that fall within the spirit and scope of the basic underlying principles disclosed above and claimed herein