A material transport system for delivering and dispensing a large capacity of materials at a construction site using a plurality of removable carriages, each bearing a roll of material, mounted on a movable frame. The frame comprises a pair of dual powered axles each driving either a set of drive flanged rollers, or a set of conveyors, for moving the system along purlins, or joists, of a building. The flanged rollers are used when dispensing of material to a side wall of the building is desired and the building is roofless, and when dispensing of material to an end wall of the building is desired and the building is roofed. The conveyors, which are removably mounted to the underside of the material transport system, are used for dispensing material to a side wall when the building is roofed, and when dispensing material to an end wall when the building is roofless. In either case, the flanged rollers, or the conveyors, are simultaneously driven by a common pair of dual-powered axles to negotiate the constant or changing elevation of a building's roof structure.

CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the priority benefit of U.S. Provisional Patent Application No. 60/452,047 filed Mar. 4, 2003. 


   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention relates to moving materials on walls of building structures, and more particularly, to an apparatus for use in installing insulation, or other flexible materials, or for generally moving materials on walls of building structures. 
   2. Description of Related Art 
   During the fabrication of metal frame buildings, wall installation is commonly installed by placing a roll of insulation on a carriage and supporting the carriage on the building roof framework. The carriage travels across the roof along a side wall as strips of insulation are dispensed from the roll and secured to the building wall. Typical apparatii of this type are disclosed in U.S. Pat. Nos. 3,992,847 and 4,078,355. In another arrangement, disclosed in U.S. Pat. No. 4,383,398, a cage supported on tines of a forklift carries two rolls of insulation with one being above the other. 
   When an apparatus of the type described above is used along a portion of the roof that is horizontal, the insulation hangs straight down for easy installation. However, when such an apparatus is used along a building wall where the roof slopes from one end of the wall to another end of the wall, the carriage is inclined to the horizontal from side-to-side and strips of insulation do not hang straight down from the carriage. As a result, the insulation is slanted, or otherwise misaligned, relative to the walls it is to be installed in and additional handling of the insulation is required prior to final installation of the insulation. Therefore, it would be desirable to have an arrangement for leveling the axis of the roll of insulation when the carriage is inclined so that the insulation, or other material, delivered from the carriage is properly aligned with the walls. 
   Further, the carriage tends to slide, or lose traction, when traveling uphill or downhill on a sloping roof. Thus, it would be desirable to provide a positive drive arrangement to ensure that the carriage will not slip, or lose traction, even when traveling along the incline of a sloping roof. Such drive arrangement could be a positive drive system. 
   An apparatus of the type described above commonly supports only one roll of insulation, or a second roll that is not conveniently movable to a dispensing position. As a result, manual intervention is often required to supply additional rolls of insulation material, or to position a second roll appropriately for dispensing from the carriage. Thus, it would be desirable to have a carriage system whereby a plurality of rolls of insulation, or other materials, is supported and is easily indexed when a prior roll of insulation, or other material, is exhausted. In this manner, all, or a significant portion, of a building wall may be insulated before it is necessary to reload the carriage with additional rolls of insulation. 
   SUMMARY OF THE INVENTION 
   This invention provides a material transport system for delivering and dispensing a large capacity of materials at a construction site using a plurality of removable carriages, each bearing a roll of material, mounted on a movable frame. The frame comprises a pair of dual powered axles each driving either a set of drive flanged rollers, or a set of conveyors, for moving the system along purlins, or joists, of a building. Thus, the changing elevation of purlins, or joists, of the building corresponding to the slope of the roof along an end wall of the building, or the constant elevation of the building along side walls of the building, may be negotiated by either the flanged rollers, or the conveyors. 
   In conditions where roof sheeting has not yet been installed, the flanged rollers are used when installation of material to a side wall of the building is desired, and the pair of conveyors, which are removably mounted to the underside of the flanged rollers, are used when installation of material to an end wall of the building is desired. In conditions where roof sheeting has been installed, the flanged rollers are used for installing material at the end wall by moving the system along the changing elevation of purlins, or joists, of the building corresponding to the slope of the roof at the end walls of the building, and the pair of conveyors are used for installing material to a side wall of the building. In each case, the flanged rollers, or the conveyors, are simultaneously driven by a common pair of dual-powered axles. Experimentation has determined that use of a single conveyor with a single set of flanged rollers undesirably skews the materials dispensed when negotiating the slope of an end wall. Accordingly, the dual conveyors are preferred to better align the materials dispensed when negotiating an end wall slope. Additionally, experimentation has determined that the substantially increased mass of installed material results in a significant rolling resistance of the material transport system. To overcome this rolling resistance, it is beneficial that each point of contact with the roofing structure, or exposed purlins, assist in the movement of the material transport system. 
   This invention separately provides that each conveyor is comprised of a plurality of pulleys spaced approximately three inches apart from one another. Each conveyor includes a single dual-grooved drive pulley which in turn moves two high-friction belts. One of these belts extends over one set of a plurality of pulleys in one direction, and the other belt extends in an opposite direction over another set of a plurality of pulleys. Thus, by rotating the belts of each conveyor the material transport system is moved from one position to a next position along the end wall, for example, of the building. The full compliment of pulleys thus frictionally engages the belts with the purlins, or joists, the system is riding upon. These conveyors are generally used in pairs in which one conveyor extends substantially in one direction while the other conveyor is inversely positioned relative to the first conveyor so as to extend substantially in the opposite direction. At least one common drive axle links the pair, or pairs, of conveyors. A typical application would have two pairs of conveyors, in fore and aft positions relative to the roll dispensing carriage. That is, one pair is mounted near one end of the material transport system and another pair mounted at an opposite end of the material transport system. Additional individual conveyors or pairs of conveyors could also be added to increase the loading capacity of the material transport system. 
   This invention separately provides that each conveyor is comprised of a first toothed drive pulley at one end of each conveyor, a second idler pulley at a position very near the first pulley, and a third idler pulley at an end of each conveyor opposite the first pulley. A high-friction toothed belt is provided to ride over the first, second, and third pulleys of each conveyor and to engage the purlins, or joists, the system is riding upon. Thus, by rotating the drive pulley and belt of each conveyor, the material transport system is moved from one position to a next position along the side wall or end wall of the building as desired. These conveyors are generally used in pairs in which one conveyor extends substantially in one direction while the other extends substantially inverse the first conveyor so as to extend in the opposite direction. At least one common drive axle links the pair, or pairs, of these conveyors. A typical application would have two pairs of these conveyors, one pair mounted near one end of the material transport system and the other pair mounted at an opposite end of the material transport system. Additional individual conveyors or pairs of conveyors could also be added to increase the loading capacity of the material transport system. 
   This invention separately provides a material transport system for delivering and dispensing a large capacity of materials at a construction site wherein the frame of the material transport system bearing the materials is adjustable to compensate for varying roof pitches. Upright structures of the frame are provided with a set of holes at elevations corresponding to standard roof pitches, for example a slope having a 1-inch rise to a 12 inch run. Pins are insertable into the desired hole on each upright structure so that the roll of material to be dispensed is securely mounted to the frame for dispensing at a proper angle relative to the intended end wall. In this manner, the materials dispensed from the material transport system are properly aligned with end walls, for example, even as the material transport system negotiates the different elevations of the end wall slope. When the materials are dispensed to a side wall, pins are likewise inserted into a hole of a same elevation in each upright structure to ensure that the materials are evenly dispensed and appropriately aligned for installation into a side wall. 
   This invention separately provides a material transport system for delivering and dispensing a large capacity of materials at a construction site wherein the indexing, or re-supplying, of subsequent rolls of materials is more readily accommodated by removing a first, or otherwise preceding, supply carriage to position a subsequent supply carriage, with a subsequent roll of material, for dispensing at a dispensing end of the system. Each supply carriage is thus removable from the frame of the system by removal of a pin, or set of pins, that otherwise secures each supply carriage to the frame. Once a preceding supply carriage is removed, a subsequent supply carriage may be positioned at the dispensing end of the frame just vacated by the removed supply carriage. The subsequent supply carriage is then secured by the pin, or set of pins, that originally secured the preceding supply carriage to the frame. Any remaining supply carriages are similarly secured by a pin, or set of pins, to the frame until repositioning to the dispensing position is desired. 
   This invention separately provides a tensioning device that renders the insulation, or other material, taut after a desired amount of the insulation, or other material, has been dispensed. The tensioning device is a rotationally indexable device that is operable from either side of the system. 
   In the various exemplary embodiments of this invention, the dimensions of the material transport system enable the system to be moved from one construction site to another in a standard full-sized pick-up truck. Further, the frames of multiple material transport systems may be nested with one another so as to transport a plurality of material transport systems in one vehicle at one time. 
   This invention separately provides that a plurality of the various exemplary embodiments of the material transport system described above may be linked to one another to form a material transport system train. This linking can be comprised of at least one of mechanically linked frame sections, mechanically linked drive axle sections, or electrically linked drive motor control systems. The linking of various material transport systems to one another may also be comprised of combinations of mechanically linked frame section, mechanically linked drive axle section, or electrically linked drive motor control systems. Such a train, comprised of linked material transport systems., enables even larger amounts of materials to be moved at a construction site, if needed. 
   These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various exemplary embodiments of the systems and methods of this invention will be described in detail with reference to the following figures, wherein: 
       FIG. 1  illustrates an exemplary building structure on which the material transport system of the invention may be used; 
       FIG. 2  illustrates an overhead view of an exemplary material transport system according to the invention riding on purlins, or joists, of a building; 
       FIG. 3  illustrates a perspective view of a first exemplary embodiment of the material transport system according to the invention; 
       FIG. 4  illustrates another view of the first exemplary embodiment of  FIG. 3 ; 
       FIG. 5  illustrates an exemplary motor arrangement according to the invention; 
       FIG. 6  illustrates a perspective view of the tensioning unit according to the invention; 
       FIG. 7  illustrates a partial view of the tensioning unit for mounting to the material transport system according to the invention; 
       FIG. 8  illustrates a perspective view of the roll supply carriage according to the invention; 
       FIG. 9  illustrates a partial view of the roll supply carriage mounted to the material transport system according to the invention; 
       FIG. 10  illustrates a second exemplary embodiment of conveyors according to the invention; and 
       FIG. 11  illustrates an exemplary embodiment of multiple material transport systems coupled to one another. 
   


   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   Referring now to the  FIGS. 1–11  of this Application,  FIG. 1  shows an exemplary building  1  upon which the material transport system  100  ( FIG. 2 ) of the invention might be used. The building  1  is comprised of opposed side walls  2 ,  3 , opposed end walls  4 ,  5 , and purlins  6  underlying a roof  7 . The roof  7  thus slopes upwardly from an eave-strut  8  at a top of each side wall  2 ,  3  to a ridge  9  at the top of the building  1 . The purlins  6  span longitudinally across the building  1  from end wall  4  to end wall  5 . The purlins  6  further are spaced approximately equi-distant from one purlin to another purlin from the eave strut  8  to the ridge  9  in a generally parallel manner relative to the eave-strut  8  at the top of each side wall  2 ,  3 . 
     FIG. 2  shows an overhead view of an exemplary embodiment of the material transport system  100  atop the building  1 . The building  1  shown is generally roofless. The material transport system  100  shown in  FIG. 2  generally traverses across the longitudinal span of the purlins  6 , generally parallel to the eave-strut  8 , so that material from one of rolls  20 ,  21  is dispensed in alignment with the side wall  2 , for example. Because the elevation of the side walls  2 ,  3  is constant, and because the elevation of the material transport system  100  on the purlins  6  is constant as it traverses across the purlins  6 , the material dispensed from one of the rolls  20 ,  21  is also constantly dispensed in alignment with the side walls  2 ,  3  as desired. 
   Were the material transport system  100  re-oriented to dispense material from one of the rolls  20 ,  21  to the end walls  4 ,  5  of the roofless building  1 , then the material transport system  100  would further comprise belted conveyors  140  ( FIG. 3 ) to negotiate the changing elevation of the roof  7  as the purlins  6  ascend from the side walls  2 ,  3  to the ridge  9  of the building  1 . The changing elevation of the roof  7  at the top of the end walls  4 ,  5  corresponds to the rise versus the run slope of the roof  7 . The span of the conveyors  140  add stability to the material transport system  100  as it traverses the changing elevations of the end walls  4 ,  5 , for example. 
   The material transport system  100  includes flanged rollers  130  ( FIG. 3 ) on the underside of the frame  110  of the system  100 . High friction sections  134  of the flanged rollers  130  ride over the exposed purlins  6 , joists, eave-strut  8  of a roofless building  1  when dispensing material from one of the rolls  20 ,  21  to the side walls  2 ,  3 . Of course, though the building  1  shown in  FIGS. 1 and 2  is generally roofless, the high friction wheels  134  of the flanged rollers  130  could instead traverse across the roof  7  of the building  1  when dispensing material to end walls  4 ,  5  were the roof  7  already in place. Low friction flange sections  135  of the flanged rollers  130  help to guide the wheels  130  and maintain a generally straight path for the system  100  as it traverses the roof. The low friction flange sections  135  could be made to comprise a coating such that damage to the materials comprising the roof  7  is minimized and power requirements are reduced. On the other hand, the high friction central sections  134  of the flanged rollers  130  could be comprised of a coating such that the central sections  134  grip and travel smoothly over the desired portions of the building. 
   Thus, the frame  110  of the material transport system  100  traverses the purlins  6  in a path generally parallel to the eave strut  8  along the top of the side walls  2 ,  3 , for example. As the desired length of the insulation, or other material, is dispensed from one of the rolls  20 ,  21  the bottom portion of the insulation, or other material, may be attached adjacent the bottom of the side walls  2 ,  3  by screws, or other suitable fasteners, for example. 
     FIG. 3  shows a perspective view of a first exemplary embodiment of the material transport system  100  according to the invention. The material transport system  100  comprises a generally rectangular frame  110  comprised of variously lengthed u-shaped channel struts  111 ,  112  fastened together by cornerposts  113 . The cornerposts  113  may be comprised of angle-irons, for example, to which the upper and lower struts  112  and  111  are attached. Thus, the longest struts  111  comprise the longer sides of the rectangular frame  110 , the shorter struts  112  comprise the ends of the frame  110 , and the cornerposts  113  are the vertical members joining corresponding upper and lower struts  111 ,  112  of the frame  110  together. Additional posts  114  may be place between the cornerposts  113  to increase the strength and rigidity of the frame  110  and to join the upper and lower sets of struts  111 ,  112  together. The posts  114  are comprised of square tubing, for example, that attach at either end of the posts  114  to the respective struts  111 ,  112 . The majority of the framing system is assembled by welding the various struts, cornerposts, and posts  111 – 114  together. A suitable fastener is contemplated for securing the other components together throughout this application. Such fasteners may be screws, bolts, pins, clips, straps, or other known or later developed fastening devices. 
   Referring to  FIGS. 3 and 4 , a substantially square drive axle  120  is mounted on the underside of the frame  110  by attachment to each of the lower struts  111 . A plurality of, for example three, flanged rollers  130  are slidably mounted on each of the drive axles  120  by a collar  131  and a square fitting  132  provided with each flanged roller  130 . Each of the slidably mounted flanged rollers  130  is thus driven by the square drive axle  120  when motor  200  is operated causing a chain  202  arranged over a series of sprockets  204  to rotate the drive axle  120 . Rotation of the drive axle  120  thus causes the flanged rollers  130  to rotate and traverse the material transport system  100  across the exposed purlins  6 , or the roof  7 , permitting material to be dispensed from the rolls  20 ,  21  along a side wall  2 ,  3 . 
   As shown in  FIG. 5 , the motor  200  may comprise a controller  210  mounted to the frame  110  of the material transport system  100 . A tethered line  211  attached to the controller  210  permits an operator to direct the motion of the material transport system  100  in the forward, reverse or stopped directions. The motor  200  may as well comprise a speed feature to control the rate at which the material transport system  100  is moved. 
   L-shaped plates  115  ( FIG. 4 ) on each square drive axle  120  attaches each square drive axle  120  to a respective one of the lower struts  111  by fastening one end of the L-shaped plate  115  to the lower strut  111 , and fastening another end of the L-shaped plate  115  to the collar  131  provided with each of the flanged rollers  130 . The fastener permits each flanged roller  130  to be positioned as desired along the square drive axle  120 . Each collar  131  thus mounts a flanged roller  130  to the square drive axle  120  by sliding the square fitting  132  and the collar  131  onto the corresponding square drive axle  120 . As a result of this configuration, the flanged rollers  130  may be moved along the square drive axle  120  by loosening the fastener fastening the L-shaped plate  115  to the strut  111  and sliding the flanged roller  130  to a different position on the square drive axle  120 . Thereafter, the fastener can be re-tightened to secure the flanged roller  130  in its new position on the square drive axle  120 . The positioning of the flanged rollers  130  in different positions becomes necessary when attaching, or detaching, the conveyors  140 , both of which will enable the material transport system  100  to move across the roof or exposed purlins of the building as needed according to roofed or roofless conditions. Some flanged rollers may be classified as uphill or downhill flanged rollers, depending on the direction in which the rolling surface extends away from the flanged surface. If necessary, the flanged rollers can be repositioned to accommodate various application needs. 
     FIG. 3  further shows an exemplary embodiment of the conveyors  140  attached to the underside of the lower struts  111 . Each conveyor  140  generally comprises two substantially parallel frame members  141  forming a channel housing a plurality of pulleys  142  therein. The frame members  141  are joined by plates  143  mounted to a top of the frame members  141 . An L-shaped plate  144  ( FIG. 3 ) also attaches the top of the frame members  141  to the lower strut  111  of the frame  110  of the material transport system  100 . 
   Two of the plurality of pulleys  142  provided in the conveyors  140  are drive pulleys  145  ( FIG. 3 ) provided in each conveyor  140 . The drive pulleys  145  are provided with square fittings corresponding to the square drive axle  120 . The conveyors  140  are thus mounted to the material transport system  100  by sliding the square fittings of the two drive pulleys  145  over the square drive axle  120 . Two conveyors  140  are preferably attached to one another at either end of the frame  110  in order to provide an increased span of the conveyors  140  over the purlins  6  or roof  7 , and thereby to provide increased stability of the material transport system  100 . In the case of pairs of attached conveyors  140  at both ends of the material transport system  100 , the square drive axle  120  links pairs of drive pulleys  145  at each end of the system  100  and urges the material transport system in the desired direction. Of course, alternatively, a single conveyor  140  may be mounted at each end of frame  110 , if desired. 
   A belt  147  rides over the plurality of pulleys  142 , including the dual-groove drive pulley  145 , in each conveyor  140 . As shown in  FIGS. 3 and 9 , the conveyors  140  are generally perpendicular to the square drive axles  120  such that, operation of motor  200  causes a drive chain  202  to rotate the square drive axle  120 , which thus rotates the drive pulley  145 . As a result, belts  147  move over the plurality of pulleys  142  and drive pulleys  145  to move the material transport system  100  across the roof  7 , or exposed purlins  6 , of building  1  generally parallel to the eave strut  8  along the side walls  2 ,  3  or across the changing elevation of the purlins  6  for end walls  4 , 5  in order to dispense material from the rolls  20 ,  21 . 
   Thus, operation of the motor  200  and drive chain  202  causes the high friction sections  134  of the flanged rollers  130  either to traverse roof  7  for installing material at end walls  4 , 5  when the building has its roof  7  already in place, or causes the high friction sections  134  of the flanged rollers  130  to traverse the exposed purlins  6 , joists or eave-strut  8 , for installing material at side walls  2 , 3  when no roof  7  is in place. Alternatively, operation of the motor  200  and drive chain  202  causes the conveyors  140  to traverse the roof  7  for installing material at side walls  2 , 3  when the building has its roof  7  already in place, or to traverse the changing elevation of the purlins  6  for installing material at end walls  4 , 5  when the roof  7  is not in place. In this manner, the constant elevation of the roof  7  along the top of the side walls  2 ,  3  is negotiated by using either the high friction sections  134  of the flanged rollers  130  when roofed sheeting  7  is not present, or by conveyors  140  when roofed sheeting  7  is present. ( FIG. 2 ). On the other hand, the changing elevation of the end walls  4 ,  5  of a building is negotiated by using the conveyors  140  when roofed sheeting  7  is not present, and is negotiated by the high friction sections  134  of the flanged rollers  130  when roofed sheeting  7  is present. In either case, the material transport system  100  is able to dispense material from rolls  20 ,  21  to side walls  2 ,  3  or end walls  4 ,  5  of a building  1  as desired. 
   As shown generally in  FIG. 3 , at a dispensing end of the frame  110  a tensioning unit  160  is provided. The tensioning unit  160  is mounted to the cornerposts  113  of the frame  110 . The cornerposts  113  are provided with a plurality of holes  116  ( FIG. 7 ) so that the tensioning unit  160  can be adjustably mounted to the cornerposts  113 . The holes  116  permitting the adjustable mounting of the tensioning unit  160  to the cornerposts  113  of the frame  110  generally correspond to holes  183  ( FIG. 8 ) adjustably mounting the roll supply carriage  180  to cornerposts  182  of the carriage  180 , as will be discussed further below. While the tensioning unit  160  is shown at one end generally, it should be appreciated that the tensioning unit  160  could as well be provided at the opposite end of the frame  110  by mounting it to cornerposts  113 , which are similarly provided with holes  116 , at the opposite end of the frame  110 . In this manner, increased versatility of the material transport system  100  is achieved. 
   In either case, as shown in more detail in  FIGS. 6 and 7 , the tensioning unit  160  comprises a pair of spaced parallel pinch bars  161 ,  162  that extend between substantially parallel tensioning unit frame members  163  at the selected dispensing end of the frame  110 . The frame members  163  mount to the cornerposts  113  with fasteners through holes  116  as discussed above. Pinch bar  162  is stationary, whereas pinch bar  161  is movable via a linkage  164  connecting both ends of the pinch bar  161  to the frame members  163  of the tensioning unit  160 . A sprocket  165  is further provided on both sides of the movable pinch bar  161 . The sprocket  165  is engaged by a spring loaded pin  166  provided on a side of each frame member  163  of the tensioning unit  160 . A hand crank  167  is also provided at either end of the tensioning unit  160  to rotate the pinch bar  161  and crimp the insulation, or other material, passed between the pinch bars  161 ,  162 . Providing such hand cranks  167  on either side of the tensioning unit renders operation of the tensioning unit  160  more accessible to operators, who may be at different locations relative to the tensioning unit  160 . 
   As more readily seen in  FIGS. 6 and 7 , the pinch bars  161 ,  162  permit the insulation, or other material, provided from one of the rolls  20 ,  21  to pass between the pinch bars  161 ,  162  by retracting the spring loaded pin  166  and rotating the sprocket  165  to position the pinch bar  161  at its uppermost position, and then engaging the pin  166  with the sprocket  165  to lock the pinch bar  161  in this uppermost position. After the desired amount of insulation, or other material, is dispensed from one of the rolls  20 ,  21 , the spring loaded pin  166  is again retracted and one of the hand cranks  167  is rotated to rotate the pinch bar  161  and crimp the insulation, or other material, between the pinch bar  161  and pinch bar  162 . Then, the pin  166  is re-engaged with the sprocket  165  to locate the pinch bar  161  at the desired crimping position relative to the stationary pinch bar  162 . By rotation of the pinch bar  161  via the hand crank  167 , sprocket  165  and pin  166  configuration, the tensioning unit  160  comprises a gripping or pinching device applying tension to a strip of insulation, or other material, hanging downwardly along a side wall  2 ,  3  or end wall  4 ,  5  from the frame  110  of the material transport system  100 . 
   Referring back to  FIG. 3 , two roll supply carriages  180  are provided on top of the frame  110  of the material transport system  100 . Because the supply carriages  180  are essentially interchangeable, description of only one supply carriage  180  is provided herein. 
   As shown more clearly in  FIG. 8 , each supply carriage  180  is comprised of upper and lower cross-members  181  joined by cornerposts  182 , the cross-members  181  and cornerposts  182  comprising a rectangle. Each cornerpost  182  includes a series of holes  183 . A pair of adjustable uprights  184  are insertable into the cornerposts  182 . The pair of uprights  184  are adjustably attached to the cornerposts  182  by pins, or other fasteners, penetrating the holes  183  to securely position the uprights  184  at a level corresponding to the slope of the roof the material transport system  100  is to encounter. The cross-members  181 , cornerposts  182  and uprights  184  are comprised of square tubing, for example. Additional posts may be added between the cornerposts  182  to join the upper and lower cross-members  181  and add strength or rigidity to the supply carriage  180 . A roll supply bar  190  is provided across the uprights  184  for the rolls  20 ,  21  of insulation, or other material, to be dispensed by the material transport system  100 . The roll supply bar  190  includes a stationary flange  196  and an axially adjustable flange  195  to contain various widths of rolls  20 ,  21 . 
   The holes  183  in the cornerposts  182  of the carriage  180  generally correspond to the holes  116  ( FIG. 7 ) of the cornerposts  113  that renders mounting of the tensioning unit  160  adjustable, as discussed earlier. In this manner, both the supply carriage  180  and the tensioning unit  160  may be oriented to accommodate the same roof slope by positioning the supply carriage  180  and tensioning unit  160  into the same level of holes  116 ,  183  for the respective components. As a result, the insulation, or other material, dispensed from the rolls  20 ,  21  is more likely to properly align with end walls  4 ,  5  of the building when negotiating the slope of the building  1  along the end walls  4 ,  5 , or the constant elevation of side walls  2 ,  3 . 
     FIG. 9  shows a partial view of how each supply carriage  180 , is slidably mounted to each of the upper struts  111  of the frame  110  by the wheeled member  185  protruding down from the lower cross-member  181 . The wheeled member  185  thus slides into the unshaped channel of upper strut  111  at the dispensing end of the frame  110 . A similar wheeled member  185  protruding down from the lower cross-member  181  slides into the other upper strut  111  of the frame  110 . These wheeled members  185  therefore provide two points of securement of each supply carriage  180  to the frame  110  by slidably attaching the lower cross-member  181  to the upper struts  111 . 
   In addition, as best seen in  FIGS. 3  or  8 , a third point of securement of each supply carriage  180  to the frame  110  is provided by slidably mounting one side of each supply carriage  180  to an upper strut  111  via first and second support legs  186 ,  187  projecting from the upper and lower cross-members  181 . The first and second support legs  186 ,  187  form a triangular-like support structure whereby one end of the first leg  186  is attached to an interior portion of upper cross-member  181  and one end of the second leg  187  is attached to the cornerpost  182  of the supply carriage  180 . A free end of each of the first and second legs  186  and  187  abut one another and slidably connect wheeled member  188  to the upper strut  111 . In this manner, each supply carriage  180  can be slidably removed from the frame  110  of the material transport system  100  by sliding the wheeled members  185 ,  188  of the supply carriage  180  along the upper strut  111  until the entire supply carriage  180  is removed, when one of the rolls  20 ,  21  supported by the supply carriage  180  is exhausted. In this manner, a subsequent supply carriage  180  may be similarly slid along its wheeled members  185 ,  188  to assume a position at the dispensing end, for example, of the frame  110  in order to provide a fresh supply of insulation, or other material, from another of rolls  20 ,  21  for dispensing. An additional function of securing the supply carriage  180  to the upper strut  111  by first and second support legs  186 ,  187  and wheeled members  185 ,  188  is to separate each material supply carriage  180  from another such supply carriage  180  such that as material is dispensed from roll  20  mounted on one carriage  180 , it does not cause material on another roll  21  on the other carriage  180  to rotate and unravel in an opposite direction due to the frictional contact that would otherwise occur were the supply carriages  180  not separated. 
   Each carriage  180  is thus secured to the frame  110  of the material transport system  100  by pins, quick-clips, or other known or later developed fastening device as discussed earlier to preclude the wheel members  185 ,  188  and carriage  180  from sliding until sliding of the carriage  180  is desired as for removal, or re-positioning, of the supply carriage  180 . 
   Dispensing of the insulation, or other material, provided on the supply bar  190  of each supply carriage  180  is controlled, in part, by a braking device  192  ( FIG. 8 ) provided with the supply carriage  180 . The braking device  192  may be, for example, a bar, tube, or other like structure sufficient to hold the outer layer of insulation, or other material, on the rolls  20 ,  21  in place until dispensing is desired. An extendible cylinder  194 , which may be pneumatic, fluid-filled, or gas-charged, for example, attaches to a lower end of the braking device  192 . The other end of the extendible cylinder  194  is attached to the upper cross-member  181  of the supply carriage  180 . Thus, a free upper end of the braking device  192  is normally biased against the supply of insulation, or other material, of rolls  20 ,  21  on the supply bar  190  by the biasing force provided from the cylinder  194 . In this manner, the insulation, or other material, does not unravel prematurely and is more likely to be dispensed evenly, in proper alignment with the side walls  2 ,  3 , or end walls  4 ,  5  it is being provided to. Of course, one reasonably skilled in the art would readily appreciate that other biasing devices such as springs and linkages could as well be used in lieu of, or in addition to, the exemplary cylinder  194  and braking device  192  described. 
   Of course, it should be appreciated that though reference is made herein to removing a first supply carriage  180  when one of rolls  20 ,  21  is exhausted, and sliding a second supply carriage  180  to the dispensing end of the frame  110  of the material transport system  100 , one skilled in the art could as readily slide the second supply carriage  180  first, or leave the supply carriage  180  of the exhausted roll in place while indexing the braking device  192  of the exhausted supply carriage in a full retracted position and merely drape the insulation, or other material, from the fresh roll of the second supply carriage  180  over the supply roll bar  190  of the first supply carriage  180 , and proceed to dispense the insulation, or other material, from the second supply carriage in this manner, which may require removal, or re-positioning, of the braking device  192 . 
     FIG. 10  shows another exemplary embodiment of the conveyors  240  according to the invention. The conveyors  240  of this embodiment are each comprised of a series of square tubed upper frame members  246  and lower frame members  247 , and flat side plate sections  253 . The upper frame member  246  is joined to the lower frame member  247  by vertical posts  251  and the side plates  253 . The conveyors  240  are formed by welding the majority of the frame members  246 ,  247 , posts  251  and side plates  253  together, while the remaining components of the conveyors  240  are assembled by other fastening devices as discussed above. 
   Drive axle  120  thus engages a toothed drive pulley  242  (inside side plates  252 ) at one end of each conveyor  240 . The toothed drive pulley  242  contacts toothed belt  245 , which contacts idler pulleys  243 , near the toothed drive pulley  242 , and  244 , at an end of the conveyor  240  opposite the toothed drive pulley  242 . Each drive axle  120  thus engages each conveyor  240  only at the drive pulley  242 , whereas the drive axle  120  otherwise merely passes between upper  246  and lower frame members  247 , which is different from the described in previous embodiments. 
   In lieu of the plurality of pulleys as described in previous embodiments, conveyors  240  use a low-friction slider member  260  positioned between idler pulley  243  and the idler pulley  244  to contain and guide toothed belt  245 . The slider member  260  thus spans the distance generally between idler pulleys  243  and  244  and is fastened below lower frame member  247  of each conveyor  240 . 
   Each conveyor  240  slidably attaches to the lower strut  111  of the frame  110  by mounting bracket  250 , which is located near the toothed drive pulley  242  at one end of the conveyor  240 . A mounting plate  249 , towards the middle of the conveyor  240 , also attaches to the lower strut  111  of the frame  110 . 
   Outriggers  252  may be used to extend the span of the conveyors  240  and increase the stability of the material transport system  100 . Outrigger  252  is generally not intended to contact the building structure except in extreme cases were wind or other external forces may cause the material transport system to become unstable such that without the outrigger  252 , the system would potentially fall through the building structure. Outrigger  252  is thus generally only necessary where the spacing of the purlins  6 , or joists are so great as to merit the addition of said device. 
   As before, a pair of conveyors  240  are used at each end of the material transport system  100  to drive the system  100  for dispensing material at side walls  2 ,  3  when a roof  7  is present, or for dispensing material at end walls  4 ,  5  when a roof  7  is not present on a building  1 . The flanged rollers  130  are used for moving the system  100 , as in earlier embodiments, to dispense material at side walls  2 ,  3  when a roof is not present, and to dispense materials at end walls  4 ,  5  when a roof is present. In any case, the conveyors  240  are not necessarily attached to one another, as in earlier embodiments, but instead are slightly spaced from one another though in pairs at opposite ends of the material transport system, as before. 
   Thus, as shown in  FIG. 10 , a pair of conveyors  240  is mounted at each end of the material transport system  100 . Each conveyor  240  of the pair is inversely mounted relative to the other conveyor such that one of the square drive axles  120  engages the drive pulley  242  of a first conveyor  240  and the other square drive axle  120  merely passes through the frame of the first conveyor  240 , whereas the drive axle  120  passing through frame of the first conveyor  240  also engages the drive pulley  242  of the second conveyor  240 , and the drive axle  120  engaging the drive pulley  242  of the first conveyor  140  merely passes through the frame of the second conveyor  240 . A similar pair of conveyors  240  is provided at the opposite end of the material transport system. 
   As in earlier described embodiments, operation of motor  200  causes the drive axles  120  to engage the drive pulleys  242  of each conveyor  240 . Rotation of the drive pulleys  242  results in the toothed belt  245  sliding over the idler pulleys  243  and  244 , and over the elongated plastic slider element  260 . The toothed belt  245  thus urges the material transport system  100  over the roof  7  to dispense materials at side walls  2 ,  3 , and over the exposed purlins  6 , when the roof is not present, to dispense materials at end walls  4 ,  5 . 
     FIG. 11  shows a series of material transport systems  100  connected to one another to form a train  300  of material transport systems  100 . Such a train  300  may be useful to accommodate delivery of greater amounts of material to a work site. Because each frame  110  of each material transport system  100  is substantially the same as the other material transport systems  100 , the train  300  may be achieved by fastening one end of a frame  110  of a first system  100  to an adjacent end of a frame  110  of another system  100  For example, a first material transport system  100  may be mechanically linked to a second material transport system  100  by fastening the frames  110  of each system  100  together as by bolting, or otherwise fastening adjacent struts  111 ,  112  and cornerposts  113  together. Alternatively, or in addition thereto, the drive axles  120  of each adjacent material transport system  100 , may be linked by slidably positioning one of the flanged rollers  130  to bridge ends of the adjacent drive axles  120  together. Still further, and again in addition or alternatively to the above, adjacent material transport systems  100  could be electronically linked such that a single controller  210  ( FIG. 5 ) operates the entire train  300 . Such electronic linkage could, for example, operate each material transport system  100  of the train  300  in series off of one controller  210 . 
   Of course, one skilled in the art would readily know and understand that the material transport systems  100  described herein may as easily transport material other than, or in addition to, the insulation, or other rolled materials described herein. For example, HVAC systems, bricks, mortar boxes, walling materials, etc., may as well be transported with minimizes manual intervention. 
   While this invention has been described in conjunction with the specific embodiments described above, it is evident that many alternatives, combinations, modifications, and variations are apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention set forth above are intended to be illustrative, and not limiting. Various changes can be made without departing from the spirit and scope of this invention.