Abstract:
A system for transporting materials that traverses seams and stepped sections of a standing-seam type roof includes two trolleys, the lower one of which has ridges on its top simulating roof seams and upon which the wheels of the upper trolley can be placed. When a step in the roof is encountered, the upper trolley can be rolled off the lower trolley onto the upper section of the roof.

Description:
[0001]     This application is a division of copending application Ser. No. 10/903,856, filed Aug. 2, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Typical panel roofing consists of successive metallic sheets of paneling laid side-by-side to form a roofing cover. Each roofing panel is formed by a panel producing machine from metal sheet stock, typically fed from a roll of sheet metal. Forming each panel can include molding ribs down the panel length and forming both lengthwise edges of each panel to enable a mating fit between the abutting lengthwise edges of adjacent panels. Clips interleaved between the adjacent panel edges affix the panels to the roof surface.  
         [0003]     Some panel roofs are constructed with panels spanning the width of the roof to eliminate perpendicular seams that have compromised weather-tight integrity. However, with the advent of the Butler MR-24® Roof System, and a seaming machine called a Roof Runner®, shown in U.S. Pat. No. 3,120,828, issued Feb. 11, 1964 to S. O. Gronlund, which can seam the panels with water-tight integrity, roofers have been relieved of having to produce and manipulate large, unwieldy panels on-site to provide a weather-impervious roofing cover.  
         [0004]     Prior to installation of panel roofing, the panels must be hoisted to roof level for installation. Once on the roof, the panels then must be transported to a desired position on the roof. If the roof is large, roofers may need to transport the individual panels over substantial distances, including stepped up sections, as described below.  
         [0005]     Particularly large surfaces ordinarily are not roofed in a generally continuous, or single-level, surface to avoid the deleterious effects of thermal expansion naturally occurring in the individual roofing panels. That is, over large surfaces, individual roofing panels expand or contract, depending on weather and sun conditions, which may weaken inter-panel seams or even create gaps and expose the building and occupants thereof. Stepping roof sections, or elevating one section relative to an adjacent section by several inches, eliminates this exposure potential. However, stepping a roof renders material transport more problem-atic because roofers need to lift the heavy, elongated roofing materials over the step between adjacent sections in a coordinated fashion.  
         [0006]     Stackable trolleys are disclosed in U.S. Pat. No. 3,523,694, No. 3,608,921, No. 5,711,540, No. 6,079,720, and No. 6,257,152. However, known stackable trolleys are designed to maintain relative positioning among stacked trolleys, not to allow for movement of superposed trolleys.  
         [0007]     What is needed, and not taught or suggested in the art, is a trolley for transporting materials that can traverse seams and stepped sections of a roof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The invention is described in detail below with reference to the following figures, throughout which similar reference characters denote corresponding features consistently, wherein:  
         [0009]      FIG. 1  is an environmental perspective view of an embodiment of a trolley for transporting materials constructed according to principles of the invention;  
         [0010]      FIG. 2  is a bottom front right perspective view of the embodiment of  FIG. 1 ;  
         [0011]      FIG. 3  is an is an environmental perspective view of another embodiment of the invention;  
         [0012]      FIG. 4  is an environmental perspective view of another embodiment of the invention;  
         [0013]      FIG. 5  is an enlarged perspective view of a portion of the embodiment of  FIG. 4 ;  
         [0014]      FIG. 6  is an environmental perspective view of another embodiment of the invention;  
         [0015]      FIG. 7  is an enlarged environmental front view of a portion of the embodiment of  FIG. 6 ; and  
         [0016]      FIG. 8  is an enlarged environmental side view of the portion of  FIG. 7 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]      FIG. 1  shows a trolley  100  for transporting materials that traverses seams S of a roof R. The trolley  100  has a bed  105  mounted on aligned frames  110  that house wheels  115 . Once the trolley  100  is positioned on seams S, roofing materials (not shown) are hoisted onto the trolley  100  for transportation to where the materials are needed.  
         [0018]     As viewed along direction A, the bed  105  defines a box section  120  which provides lateral structural integrity while minimizing weight. This lightweight construction allows roofers to move the trolley  100  readily to and among seams S of roof R and, once located on roof R, hoist significant amounts of roofing material thereon. To aid in moving the trolley  100  to the roof and/or among the seams, the bed  105  has a handhold 117 configured to receive a roofer&#39;s hand for lifting and moving the trolley  100 . Referring also to  FIG. 2 , the underside of the box section  120  may include one or more ribs  125  to enhance structural integrity. The bed  105  has horizontal flanges  123  for mating with the frames  110 .  
         [0019]     Each frame  110  includes symmetrically disposed L-shaped brackets  130 , each having a horizontal flange  135  and a vertical flange  140 . The horizontal flanges  135  mate with and may be welded or otherwise fixed to the horizontal flanges  123  of bed  120 . The vertical flanges  140   a  and  140   b  each have a plurality of throughbores (not shown) that are in registry for receiving a like number of axles  145 . A nut  150  retains each axle  145  in each bracket  130 .  
         [0020]     Referring to  FIG. 2 , the wheels  115  are rotatingly disposed on each axle  145 . Each wheel  115  has a peripheral groove  155  configured to receive and readily roll on roof, guided by seam S, as shown in  FIG. 1 . Each wheel  115  also may have a peripheral traction element  160 , such as a tread, knurling or the like.  
         [0021]     Frames  110   a  and  110   b  are arranged so that the lateral spacing  165  between grooves  155   a  and  155   b  corresponds to the spacing between seams S, known as seam-to-seam pitch. When constructing standing seam roofs from prefabricated roof panels, this seam-to-seam pitch is fixed or consistent everywhere on the roof, except for unintended minor localized variations. The lateral spacing  165  of wheels  115  allows the trolley  100  to ride along seams S over an entire roof width.  
         [0022]     Referring to  FIG. 3 , in addition to accessing the entire width of a single-level roof R, that is, a section of roof R defining a substantially continuous surface, another embodiment of the invention is a trolley  600  that provides for moving materials to roof sections of different levels to access stepped-up sections of roof R. The trolley  600  is largely identical to trolley  100 , except that the trolley  600  includes a deck  603  mounted on frames  610  with threaded fasteners  613  or in any other conventional manner. The deck  603  is constructed from heavy gauge or enhanced-strength material to support, for example, the trolley  100  and materials loaded thereon.  
         [0023]     On top of the deck  603  there are two simulated seams  617 , which are configured, positioned and aligned similar to the seams in a seamed roof. The height  670  of the deck  603 , the vertical spacing  675  between the flange  635  and the axle  645 , and the size of the wheel  615 , determine the clearance  680  between roof R b  and frame  610 , are configured to provide an overall trolley height  685 , as shown in  FIG. 1 , corresponding to the step up  190  between stepped adjacent roofing sections R a , R b . The trolley  600  may include a mechanism for adjusting the height  685 .  
         [0024]     In practice, when moving materials between stepped sections R a , R b  of roof R, a second trolley  100  is positioned on a the lower trolley  600 . The upper trolley may be pinned or otherwise impermanently fixed to the lower trolley prior to being loaded with materials. Once loaded with materials, roofers may roll the trolley  600  along seam S b  with the trolley  100  and materials firmly secured thereon. Upon reaching the step U between section R a  and section R b , the trolley  100  is disconnected from the trolley  600 . The upper trolley  100  then may be rolled onto seam S a  along with the materials.  
         [0025]     Referring to  FIG. 4 , another embodiment constructed according to principles of the invention is a trolley  400  that is largely identical to the trolley  100 , except that trolley  400  includes a brake  500  which includes two handles  505  interconnected with a rod  510 . Referring also to  FIG. 5 , the rod  510  is fixed to an arm  515  to which is removably attached a brake pad  520 . The rod is normally biased to urge the arm and the brake pad against roof R with enough friction to produce sufficient braking force to slow or prevent trolley motion, as shown in  FIG. 4 . This safety feature significantly reduces job site accidents and injuries.  
         [0026]     Referring to  FIG. 5 , the rod  510  is received through registered throughbores  443  in each vertical flange  440  of frame  410 . A shouldered bushing  447  may be employed in the outer flanges  440   a  for closer tolerances between the rod  510  and the outer flanges  440   a . The arm  515  has an adjustable collar  453  for frictionally engaging the rod  510 . A coil spring  560  has one end (not shown) fixed relative to the rod  510  with an adjustable collar  565  and another end (not shown) fixed relative to the frame  410 .  
         [0027]     A knuckle  570  is fixed at an orientation on the rod  510  so that when the handle  505  is generally vertical, the knuckle  570  contacts the frame  410  for transferring force exerted against the handle  505  to the frame  410 , thence against the trolley  400 , and thereby provides motive force to move the trolley as desired. Thus, to move the trolley, a roofer first must rotate either or both handles  505  to distance the brake pad  520  from the roof R, allowing the trolley to move. The roofer then may use the handle(s)  505  to push the trolley along the roof.  
         [0028]      FIG. 6  shows another embodiment constructed according to principles of the invention. It includes a trolley  200  that is largely identical to trolley  100 , except that trolley  200  includes a brake  300 . Preferably, the brake  300  is mounted on one of the frames  210  to which the wheels  215  are mounted. Referring also to  FIGS. 7 and 8 , the brake  300  includes a handle  305  for rotating a rod  310  to drive a pin  315  and the brake pads  320  mounted thereon against roof R. As with the brake  500 , brake  300  is normally biased into a brake position, whereby pin  315  urges brake pads  320  against the roof with enough friction to produce sufficient braking force to slow or prevent trolley motion, as shown in  FIG. 6 .  
         [0029]     The handle  305  is rotatingly mounted on the trolley  200  about a pivot pin  325 , while the handle  307  is mounted on a frame  210 . The handle  305  drives the rod  310  via a lever  317  extending from rod  310  which is rotatingly connected to the trolley  200  via journals  333 ,  335  and  340 . The rod  310  is drivingly connected to pin  315  via a yoke-and-pin cantilever  330 .  
         [0030]     The pin  315  is slidingly mounted on the trolley  200  via a spring-loaded cylinder  350 , which is comparable to a conventional shock absorber. The pin  315  engages a coil spring (not shown) that abuts an end of the cylinder  350  and normally urges the pin  315  toward the roof. When the pin  315  is drawn away from the roof, spring force increases, either in tension or compression, urging the pin  315  to return to the normally-braked position. The pin  315  has a pad holder  345  welded or otherwise fixed thereto onto which pads  320  are mounted in a conventional manner.  
         [0031]     Inasmuch as the invention is subject to many variations and modifications, it is intended that the foregoing description and the drawings shall be interpreted as merely illustrative of the invention defined by the claims below.