Abstract:
A transport apparatus for use in modular construction, specifically a dual-deck hydraulic apparatus that, while carrying a payload, can detect topology changes and adjust accordingly to keep the payload in substantially the same position. The apparatus can efficiently transport modular building components while preventing torsion and other damage. The apparatus can also adapt to off-load modules to foundations or multi-story heights.

Description:
CLAIM OF PRIORITY 
       [0001]    The following application claims priority to U.S. Provisional Patent Application No. 61/172,520, filed Apr. 24, 2009, the complete contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    A transport apparatus for use in the field of building construction, specifically an apparatus for safely transporting and off-loading modular building components. 
         [0004]    2. Background 
         [0005]    Modular building is a popular building method by which multiple modules are manufactured off-site and subsequently transported and put together on-site. Modular building can have many advantages over traditional construction, such as being less expensive and more durable. However, the transport process is a critical and often problematic step in modular construction, since each unit must travel to the building site without suffering structural or cosmetic damage. Moreover, once on-site, the units must be carefully and precisely attached to each other, which requires placement on either a foundation or on top of another module. 
         [0006]    Current transport and off-load methods are ineffective at adequately preventing damage to payloads. What is needed is a modular transport and placement apparatus that can safely and effectively deliver and position modular units. The apparatus should have a plurality of track-drive assemblies, which can move independently or in concert to adapt to uneven terrain. It is desirable to have a multi-deck configuration, wherein each deck can remain in a substantially horizontal and stable position during transport. The upper deck of a multi-deck apparatus should be adapted to rise above lower decks such that off-load can occur safely and within inches of a foundation or second floor level. 
         [0007]    The apparatus should have an elevation-changing track drive for traversing complex topology contours having indifferent angles relative to each track drive assembly. The apparatus should have the ability to adapt and traverse complex terrains directed by geometry and telemetry computerization, and should be capable of terrain mapping. Most importantly, it is desirable to have an apparatus that won&#39;t twist or otherwise damage its payload while traversing 3-D terrains that vary in elevation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  depicts a perspective view of one embodiment of a transport apparatus, without a hauler assembly. 
           [0009]      FIG. 2  depicts a perspective view of another embodiment of a transport apparatus, without a hauler assembly. 
           [0010]      FIG. 3  depicts a perspective view of a deck lift assembly. 
           [0011]      FIG. 4  depicts a side cross-section view of a deck lift assembly coupled with upper and lower decks. 
           [0012]      FIG. 5  depicts a side cross-section view of a leg assembly coupled with a drive assembly. 
           [0013]      FIG. 6  depicts an end cross-section view of a lower deck coupled with a hydraulic assembly. 
           [0014]      FIG. 7A  depicts a side view of a leg collar. 
           [0015]      FIG. 7B  depicts a top cross-section view of a leg collar coupled with an outrigger. 
           [0016]      FIG. 8A  depicts one configuration for stowing a drive assembly. 
           [0017]      FIG. 8B  depicts another configuration for stowing a drive assembly. 
           [0018]      FIG. 9  depicts a side view of a transport apparatus, including a hauler assembly, in a raised position. 
           [0019]      FIG. 10A  depicts a side view of a transport apparatus, including a hauler assembly, in a retracted position. 
           [0020]      FIG. 10B  depicts a side view of several cam lock mechanisms. 
           [0021]      FIG. 10C  depicts a side view of a frame stud. 
           [0022]      FIG. 11  depicts an end cross-section view of a retracted transport apparatus and hauler assembly. 
           [0023]      FIG. 12  depicts a leveling system of a lower deck. 
           [0024]      FIG. 13  depicts an isometric view of sensors coupled with leg and drive assemblies. 
           [0025]      FIG. 14  depicts a schematic for the operation of a leveling system. 
           [0026]      FIG. 15  depicts an alternate embodiment of an extended transport apparatus. 
           [0027]      FIG. 16  depicts the embodiment of  FIG. 15  in a retracted position. 
           [0028]      FIG. 17  depicts a bridge assembly of one embodiment of a transport apparatus. 
           [0029]      FIG. 18  depicts a top view of a transport apparatus, showing a plurality of payload drives, deck lift assemblies, and locking pin sets. 
           [0030]      FIG. 19  depicts two embodiments of a payload drive. 
           [0031]      FIG. 20  depicts details of the track drive assembly shown in  FIG. 19B . 
           [0032]      FIG. 21  depicts retracted and extended positions of one embodiment of a deck lift assembly. 
           [0033]      FIG. 22  depicts one embodiment of a set of locking pins. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    As shown in  FIG. 1 , a transport apparatus  100  can be comprised of a lower deck  102  coupled with an upper deck  104  via a deck lift assembly  106 . The bottom surface of an upper deck  104  and the top surface of a lower deck  102  can each have a plurality of longitudinal channels  108 . A plurality of channels  108  in a lower deck  102  can be pivotally coupled with a deck lift assembly  106 , while a plurality of channels  108  in an upper deck  104  can be both pivotally and slidably coupled with a deck lift assembly  106 . A lower deck  102  can be coupled with a plurality of leg assemblies  110 , each of which can be coupled with a drive assembly  112 . 
         [0035]    An upper deck  104  can comprise a non-skid surface to restrict movement of a module during transport. In some embodiments, an upper deck  104  can comprise a plurality of roller mechanisms adapted to aid in off-loading modules. In other embodiments, an upper deck  104  can be coupled with at least one rail located proximate to an edge of the deck, in order to restrict movement of and contain a module. In other embodiments, the surface of an upper deck  104  can have any other known and/or convenient surface characteristics and/or components. 
         [0036]    A leg assembly  110  can comprise an outrigger  114  that can extend from a lower deck  102 . In  FIG. 1 , outriggers  114  extend from the side of and proximate to each corner of a lower deck  102 . In alternate embodiments, outriggers  114  can extend from any other points along the sides of a lower deck  102 . In other embodiments, outriggers  114  can be coupled with the bottom surface of a lower deck  102 . In yet alternate embodiments, outriggers  114  can be coupled with a lower deck  102  in any other known and/or convenient manner and at any other known and/or convenient location. A transport apparatus  100  can comprise four leg assemblies  110 , as shown in  FIG. 1 , but in other embodiments can have any other known and/or convenient number of leg assemblies  110 . 
         [0037]    A leg assembly  110  can further comprise a leg member  116  and a leg collar  118 . A leg collar  118  can couple a leg member  116  with an outrigger  114  such that the leg member and outrigger  116   114  can be substantially perpendicular, as shown in  FIG. 1 . In some embodiments and as shown in  FIG. 1 , a leg member  116  can be a telescoping member wherein one end of the leg member  116  can be fixedly coupled with a leg collar  118 . In other embodiments and as shown in  FIG. 2 , a leg collar  118  can be slidably coupled with a non-extendable leg member  116 . In alternate embodiments, a leg member  116  can have any other known and/or convenient configuration and/or characteristics, and a leg collar  118  can be coupled with a leg member  116  in any other known and/or convenient manner. 
         [0038]    One embodiment of a deck lift assembly  106  is depicted in  FIG. 3 . A deck lift assembly can comprise a plurality of first arm members  302 , a plurality of second arm members  316 , and a deck lift hydraulic cylinder  318 . In operation, first arm members  302 , second arm members  316 , and a deck lift hydraulic cylinder  318  can move in a scissor-like fashion. First arm members  302  can be substantially parallel to each other and separated a distance substantially equal to the length of a first support member  304 . A first support member  304  can extend between and be substantially perpendicular to first arm members  302 . First arm members  302  can further comprise a brace member  314  that can prevent buckling, longitudinal rotation, and/or torsion of each arm. 
         [0039]    The proximal ends of first arm members  302  can be coupled with a roller assembly  306 . A roller assembly  306  can comprise a roller axle  308  and a pair of roller wheels  310  coupled with the ends of the roller axle  308 . A roller assembly  306  can be coupled with the proximal ends of first arm members  302  at roller assembly attachment points  312 . In  FIG. 3 , roller assembly attachment points  312  are two apertures, one in each first arm member  302 , through which a roller axle  308  can pass. In other embodiments, a roller assembly  306  can be coupled with first arm members  302  in any other known and/or convenient manner. A roller assembly  306  can be coupled with the bottom surface of an upper deck  104 , explained in detail below. 
         [0040]    Second arm members  316  can be substantially parallel, and can be pivotally coupled with first arm members  302  substantially proximate to the midpoint of first arm members  302 , as shown in  FIG. 3 . In other embodiments, second arm members  316  can be coupled with first arm members  302  at any other known and/or convenient point along the length of first arm members  302 . Second arm members  316  can be substantially parallel and can be separated by a distance less than the distance between first arm members  302 , as shown in  FIG. 3 . However, in alternate embodiments, the distance between second arm members  316  can be greater than that between first arm members  302 . In yet other embodiments, the proximal ends of second arm members  316  can be coupled with first arm members  302  in any other known and/or convenient manner. The distal ends of second arm members  316  can be pivotally coupled with the bottom surface of an upper deck  104 , explained in detail below. 
         [0041]    Each first arm member  302  can further comprise a lateral extension  322 . An extension  322  on a first arm member  302  can be located at substantially the same location along its length as an extension  322  on another first arm member  302 . A second support member  320  can be coupled with and substantially perpendicular to each lateral extension  322 , such that first and second support members  304   320  are substantially parallel. The proximal end of a deck lift hydraulic cylinder  318  can be coupled with a second support member  320 , and the distal end of the hydraulic cylinder  318  can be pivotally coupled with the bottom surface of an upper deck  104 . The coupling between a hydraulic cylinder  318  and an upper deck  104  is explained below. 
         [0042]      FIG. 4  illustrates a side cross-section view of a lower deck  102 , an upper deck  104 , and a deck lift assembly  106 . The proximal ends of first arm members  302  can be coupled with a roller assembly  306 , which in turn can be slidably coupled with a channel  108   a  in an upper deck  104 . The distal ends of first arm members  302  can be pivotally coupled with a channel  108   b  in a lower deck  102  via a backstop  402 . A backstop  402  can be positioned substantially proximate to one end of a channel  108   b,  and can be either integral with or welded or otherwise adhered to the channel  108   b.  The distal ends of second arm members  316  and a hydraulic cylinder  318  can be pivotally coupled with an upper deck  104  substantially proximate to the end of a channel  108   a.    
         [0043]      FIG. 5  depicts a side cross-section view of a leg assembly  110  coupled with a drive assembly  112 . A drive assembly  112  can comprise a motor  502 , at least one axle  504 , a plurality of drive wheels  506 , and a track  508 . A track  508  can be comprised of Kevlar® or any other known and/or convenient material. As shown in  FIG. 1 , a drive assembly  112  can comprise dual tracks, but in other embodiments a drive assembly  112  can have any other known and/or convenient number of tracks  508 . Referring back to  FIG. 5 , a drive assembly  112  can further comprise a plurality of bogie wheels  510  to aid in producing a smooth ride. A drive assembly  112  can tilt independent of a leg assembly  110  about a pivot point  512  via a track tilt cylinder  514 , as indicated in  FIG. 5 . 
         [0044]    A drive assembly  112  can be coupled with a leg assembly  110 . As shown in  FIG. 5 , a leg assembly  110  can comprise a leg member  116  coupled with a leg collar  118 . As explained above, a leg member  116  can comprise a plurality of telescoping members, and a leg collar  118  can be fixedly coupled with the leg member  116 , as shown in  FIG. 1 . In other embodiments, and as shown in  FIGS. 2 ,  5 , a leg member  116  can be non-extendable and a leg collar  118  can be slidably coupled with leg member  116 . A leg member  116  can also be coupled with at least one leg hydraulic  516  adapted to effectuate vertical movement of lower and upper decks  102   104 . A leg member  116  can also be coupled with at least one shear pin  518  to guard against damage to other components in the event of uncontrolled movement of either a telescoping leg member  116  and/or a sliding leg collar  118 . 
         [0045]      FIG. 5  shows the orientation of the x-axis and y-axis relative to the diagram, with the z-axis following the right-hand rule. As depicted in  FIG. 5 , a leg assembly  110  can rotate about the y-axis via a leg rotation cylinder  522 . Moreover, a leg assembly  110  can rotate about the z-axis via rotation of an outrigger  114  coupled with a leg collar  118 . Rotation of an outrigger  114  can be accomplished by engaging components housed within a lower deck  102 , explained below. 
         [0046]      FIG. 6  shows the orientation of the z-axis and y-axis relative to the diagram, with the x-axis following the right-hand rule. As illustrated in  FIG. 6 , a plurality of hydraulic pistons  602  and a plurality of outrigger shafts  604  can be housed within the lower deck  102  of a transport apparatus  100 . An outrigger  114  can be coupled with a substantially horizontal hydraulic piston  602  and an outrigger shaft  604 . In use, a retracted hydraulic piston  602  can protract, thus driving an outrigger  114  laterally outward so as to expose a greater segment of an outrigger  114 . In some embodiments, as shown in  FIG. 6 , an outrigger rotation cylinder  606  can be coupled with an outrigger  114  such that, when the rotation cylinder  606  is actuated, an outrigger  114  can rotate about the z-axis. 
         [0047]      FIG. 7A  depicts a side view of the leg collar  118  shown in  FIG. 5 .  FIG. 7B  depicts a top cross-section view of leg collar  118  coupled with a leg hydraulic  516  and a leg rotation cylinder  522 . A leg collar  118  can comprise a leg member shaft  702  having a cross-section geometry adapted to accommodate the geometry of a leg member  116 . An outrigger  114  can couple with a leg collar  118  at an outrigger connection point  704 , via screws, pins, adhesive, ultrasonic bonding, welding or any other known and/or convenient method of coupling. A leg collar  118  can comprise at least one leg hydraulic coupling  706 , such that, for the embodiment shown in  FIG. 5 , one end of a leg hydraulic  516  can be fixedly coupled with the leg collar  118 . In other embodiments, a leg hydraulic  516  can be slidably coupled with a leg collar  118 . In yet other embodiments, a leg hydraulic  516  can be coupled with a leg collar  118  in any other known and/or convenient manner. As shown in  FIGS. 7A ,  7 B, a leg collar  118  can further comprise at least one leg hydraulic pocket  708 . In some embodiments, a leg rotation cylinder  522  can be pivotally coupled with a leg collar  118  via a leg rotation cylinder pivot point  710 . 
         [0048]      FIG. 8  illustrates two non-limiting examples of stow options for a drive assembly  112  during transport of a transport apparatus  100 . In  FIG. 8A , a drive assembly  112  can retract into a cutaway  802  in a lower deck  102 . In such an embodiment, both a leg member  116  and a drive assembly  112  can be substantially parallel to a lower deck  102 . In another embodiment, as shown in  FIG. 8B , a leg member  116  can be substantially parallel to and positioned proximate to the underside of a lower deck  102 , while a drive assembly  112  can be positioned against one edge of a lower deck  102  in a skewed position. The abovementioned examples are non-limiting and it is recognized that several other stow mechanisms and/or configurations are available. 
         [0049]    As shown in  FIGS. 9 ,  10 , a transport apparatus  100  can further comprise a hauler assembly  902  to provide safe and efficient transport of a module. A hauler assembly  902  can comprise a hauler frame  904  positioned underneath and substantially parallel to lower and upper decks  102   104 . A hauler frame  904  can have substantially similar geometry as lower and/or upper decks  102   104 , as depicted in  FIGS. 9 ,  10 A. In other embodiments, a hauler frame  904  can have any other known and/or convenient geometry. A hauler frame  904  can comprise at least one set of hauler wheels  906  adapted to at least partially support the weight of a transport apparatus  100  and its payload. A hauler frame  904  can further comprise a tongue assembly  908  adapted to selectively couple with a truck or other motor vehicle. In the embodiment depicted in  FIG. 9 , a hauler assembly  902  is fixedly coupled with the rest of a transport apparatus  100 . In other embodiments, a hauler assembly  902  can be selectively detachable. 
         [0050]    During short-haul transport, such as when traveling on-site, a leg assembly  110  can have an in-use configuration such that a drive assembly  112  is in contact with a desired ground surface, as shown in  FIG. 9 . In such a configuration, at least one set of hauler wheels  906  can be raised off the ground surface and leg and drive assemblies  110   112  can support the entirety of a transport apparatus  100 . In other configurations, drive assemblies  112  and at least one set of hauler wheels  906  can simultaneously be in contact with a ground surface such that the weight of a transport apparatus  100  is distributed among the drive assemblies and hauler wheels  112   906 . 
         [0051]    In long-haul transport, an upper deck  104  can recess into and be flush with a lower deck  102 . Lower and upper decks  102   104  can rest on top of a hauler frame  904 , and leg and drive assemblies  110   112  can be in a stowed configuration. As shown in  FIG. 10A , in a stowed configuration leg assemblies  110  can be substantially parallel to and planar with lower and upper decks  102   104 . Drive assemblies  112  can be positioned substantially proximate to and perpendicular to the ends of a transport apparatus  100 , such that drive assemblies  112  are raised above the ground surface. 
         [0052]    An upper deck  104  and a lower deck  102  can be secured to a hauler frame  904  via anchoring mechanisms  1002 . As shown in  FIG. 10A , a first anchoring mechanism  1002   a  can secure a leg assembly  110 ; a second anchoring mechanism  1002   b  can secure a deck lift assembly  106 ; and a third anchoring mechanism  1002   c  can secure a roller assembly  306 . As illustrated in  FIG. 10B , anchoring mechanisms  1002  can be cam lock mechanisms, however in other embodiments, an upper deck  104  can be secured to a lower deck  102  via any other known and/or convenient mechanism. As shown in  FIG. 10   c , a plurality of control studs  1004  can be coupled with a hauler frame  904  and can extend into sockets in lower and/or upper decks  102   104 . Control studs  1004  can both aid in proper alignment and control lateral motion when a transport apparatus  100  is in a retracted position for transport or storage, as shown in  FIG. 10A .  FIG. 11  illustrates an alternate view of control studs  1004  coupled with upper and lower decks  104   102 . 
         [0053]      FIG. 11  depicts a latitudinal cross-section view of a transport apparatus  100 , including its hauler assembly  902 . A hauler frame  904  can further comprise a suspension system  1102  and at least one hauler axle  1104  coupled with hauler wheels  906 .  FIG. 11  further illustrates lift assemblies  106  coupled with channels  108 . As shown, channels  108  can be C-channels adapted to accept and provide stability for roller assemblies  306 . 
         [0054]    As shown in  FIG. 12 , a transport apparatus  100  can be operated via wireless controls  1201 . In some embodiments, a transpot apparatus  100  can comprise an operator box  1202  for manned control in lieu of or in addition to wireless controls  1201 . 
         [0055]    Referring to  FIG. 12 , a transport apparatus  100  can have a leveling system  1204  to prevent damage to a payload by detecting and compensating for undesirable movement of decks  102   104 . A leveling system  1204  can comprise a master sensor  1206  and a plurality of torsion control sensors  1208 , each coupled with a lower deck  102 . A master sensor  1206  can be a gyroscope that can determine orientation of a lower deck  102  in any axis at a desired time, and can be positioned substantially at the center of a lower deck  102 . In other embodiments, a master sensor  1206  can be any other known and/or convenient mechanism for detecting deck orientation. A plurality of torsion control sensors  1208  can be positioned substantially proximate to the midpoint of each end of a lower deck  102 , as shown in  FIG. 12 . Torsion control sensors  1208  can detect any twisting of a lower deck  102  relative to its center. Although  FIG. 12  depicts two torsion control sensors  1208 , alternate embodiments can include any other known and/or convenient number of torsion control sensors  1208 , and sensors  1208  can be coupled with a lower deck  102  at any other known and/or convenient location on or within a lower deck  102 . Torsion control sensors  1208  can operate in concert or independent of each other. 
         [0056]    As depicted in  FIG. 13 , a transport apparatus  100  can further comprise a plurality of distance sensors  1301 . In some embodiments, a leg assembly  110  can comprise at least one distance sensor  1301  coupled with a leg hydraulic  516 . A distance sensor  1301  coupled with a leg hydraulic  516  can be adapted to detect the distance between a predetermined point on a hydraulic  516  and a ground surface, other components of an apparatus  100 , and/or external objects. In some embodiments, a drive assembly  112  can be coupled with at least one distance sensor  1301  adapted to measure the distance to a target point on the ground surface before a drive assembly  112  reaches it. Distance sensors  1301  can be inactive when an apparatus  100  is without payload and/or during highway transport, and can be selectively activated when carrying a payload, or at any other known and/or convenient time determined by an operator. 
         [0057]    At least one speed sensor  1302  can be coupled with a leg assembly  110  and/or a drive assembly  112 , as shown in  FIG. 13 . Speed sensors  1302  can provide feedback regarding the ground speed of an apparatus  100 , such that a leveling system  1204  can compare the ground speed with the speed required to negotiate surface variations. A leveling system  1204  can then instruct drive assemblies  112  to increase or decrease track speed, either in concert or individually. In some embodiments, a drive assembly  112  can comprise at least one surface scanner  1304  that can detect surface conditions, such as wet or dry soil or clay, loose gravel, or any other desired surface condition parameter. Once a surface scanner  1304  provides feedback, a leveling system  1204  can instruct leg and/or drive assemblies  110   112  accordingly. 
         [0058]      FIG. 14  illustrates a schematic of one embodiment of the process by which a leveling system  1204  can operate. A proportional integral differential control  1401  can collect feedback from sensors and scanners coupled with front and rear leg and drive assemblies  110   112 . This feedback can then be transmitted to a central processing unit (CPU)  1402 . A master sensor  1206  and torsion control sensors  1208  can also provide feedback to a CPU  1402 . Once a CPU  1402  collects necessary data, it can then process it and send the result to a variable valve control interface  1404 , which in turn can determine desired XYZ plane positioning and instruct leg or other hydraulics to modify their positions accordingly. Appropriate actuation instructions can control deck lift assemblies  106 , tilting of drive assemblies  112 , outrigger  114  extension and rotation, and any other known and/or convenient component or assembly of an apparatus  100 . This process can ensure proper leveling of upper and lower decks  104   102  of an apparatus  100 . 
         [0059]    Data from a master sensor  1206 , torsion control sensors  1208 , sensors  1301   1302 , and surface condition scanners  1304 , can be collected in real-time to provide immediate processing and commands. In some embodiments, an apparatus  100  can be equipped with global positioning system capabilities. 
         [0060]    An alternate embodiment of a transport apparatus  100  is shown in  FIGS. 15-22 .  FIG. 15  illustrates a transport apparatus  100  in a raised configuration and  FIG. 16  illustrates a transport apparatus  100  in a retracted configuration. This embodiment of a transport apparatus  100  can utilize an over-the-road assembly comprising a lower deck  102 , an upper deck  104 , and a wheel assembly  1502 . The over-the-road assembly can be disconnected from a tractor truck via a tongue assembly  908  and a small track drive unit. This unit can manipulate the over-the-road assembly into tighter spots than possible with a tractor truck. 
         [0061]    A lower deck  102  can be limited in height for purposes of over-the-road transport. Foundations can vary in elevation from a few inches to as much as five feet, thus a transport apparatus  100  as depicted in  FIGS. 15-16  can be designed to deliver payload to foundations given those limitations. 
         [0062]    A bridge assembly  1702  is depicted in  FIG. 17 . In  FIG. 17A , a lower deck  102  is coupled with a bridge assembly  1702 , which is hidden within the framework of a lower deck  102 . In other embodiments, a bridge assembly  1702  can be coupled with an upper deck  104 . In  FIG. 17B , a bridge assembly  1702  is shown in an extended position and comprises a hinge mechanism  1704 , telescoping rail extension  1706 , a foundation coupling  1708 , and at least one vertical support member  1710 . Telescoping rail extensions  1706  can be adapted to couple with a foundation if lower than a transport apparatus  100 , or to a wall should the foundation be higher than a transport apparatus  100 . An upper deck  104  can traverse a lower deck  102  onto telescoping rail extensions  1706  and thus onto a foundation. A lateral positive track drive can push a payload unit from a transport apparatus  100  onto a foundation. As a transport apparatus  100  retracts, a payload can be stationary by friction, onsite cables, or any other known and/or convenient mechanism or method. The payload can oscillate laterally until it has departed from the limitation of an upper deck  104 . 
         [0063]    As shown in  FIG. 18 , the upper deck  104  of a transport apparatus  100  can further comprise at least one payload drive  1802 , at least one deck lift assembly  106 , and at least one set of locking pins  1804 .  FIGS. 19-20  show details of a payload drive  1802 . As illustrated in  FIG. 19 , a payload drive  1802  can comprise a hydraulic lift  1902  ( FIG. 18A ), a scissor lift mechanism  1904  ( FIG. 18B ), or any other known and/or convenient lift mechanism. The track drive assembly  1906  of  FIG. 19B  is shown in more detail in  FIG. 20 . A track drive assembly  1906  can comprise a track  2002  and a drive shaft  2004 . 
         [0064]      FIG. 21  depicts an embodiment of a deck lift assembly  106 .  FIG. 21A  shows the deck lift assembly  106  in a retracted position, and  FIG. 21B  shows the deck lift assembly  106  in a raised position. A deck lift assembly  106  coupled with upper and lower decks  104   102  can comprise a lift drive  2102 , at least one pivot arm  2104 , and a wheel assembly  2106 . A lift drive  2102  can be a hydraulic, worm drive, or any other known and/or convenient drive mechanism. 
         [0065]    A transport apparatus  100  can further comprise at least one set of locking pins  1804  adapted to secure lower and upper decks  102   104  together.  FIG. 22  depicts one embodiment of a set of locking pins  1804 , however in alternate embodiments locking pins  1804  can have any other known and/or convenient configuration. 
         [0066]    Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the invention as described and hereinafter claimed is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.