Abstract:
A roof curb installation tool has a pair of sliding hinged hooks for lifting the edge of a metal roof panel, and a pair of clamping tangs which can be secured to a vertical roof seam while a curb is being installed at a hole in the roof.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a roof curb installation tool. A curb is a structural reinforcement and a water barrier which is installed around an opening which has been made in a roof, when installing skylights, smoke and heat vents, support for mechanical equipment, and the like. Curbs are usually prefabricated, but because the necessary roof opening is almost always cut in the field, the essential reinforcing plates and diverters are difficult to place, especially in larger openings. Butler Manufacturing Company&#39;s U.S. Pat. No. 4,559,753 discloses a method of installing curbs in openings in its metal roofs. These roofs comprise metal roof which are joined in place edgewise by forming standing seams which protrude upward well above the central portions of the panels. 
     Installation of curbs around a hole cut in an existing roof is difficult labor. Normally, a worker must lift the cut edge of the sheet metal by hand in order to install, for example, a diverter plate beneath an existing panel. It would be better to have a tool for lifting and holding the edge of the metal panel. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to facilitate the placement of internally flanged curbs on metal roofs. 
     A related object is to provide workers with a tool with which they can lift up and hold the edge of a metal panel while installing a curb on a seamed roof. 
     These and other objects are attained by a roof curb installation tool as described below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, 
     FIG. 1 is an isometric view of a roof curb installation tool embodying the invention; 
     FIG. 2 is a detail of a hook carrier shown in FIG. 1; 
     FIG. 3 is a perspective view of the tool as it is first applied a curb installation job; and 
     FIGS. 4-7 show, in simplified form, a sequence of steps in which the 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A roof curb installation tool embodying the invention includes a bar  10  of metal tube stock having two or more adjustable sliding carrier assemblies  12  thereon. The bar has a rectangular (preferably square) cross section, and thus has four longitudinal edges. A four-foot length of two-inch square stock is presently contemplated, but the best dimensions may vary with the application. Longer lengths could be built up from two or more bars having a telescoping fit or complementary ends shaped as pins and sockets. 
     Two roof seam clamping  14  tangs are welded to one face of the bar, midway between its ends, and extend perpendicularly away from the face at one of the edges. 
     Each adjustable carrier assembly includes a body  16  having a sliding fit on the bar  10 , and a hook  18  attached thereto by means of a hinge  20 . The carrier is oriented with respect to the bar so that the hinges and the clamping tangs are diagonally opposite one another, when viewed along the length of the bar. 
     The ends  22  of the hooks are flat, so that they can be inserted into a narrow gap beneath a roof panel, and are bent at about a ninety degree angle approximately 2¾″ from the hinge points, allowing the hook ends to extend just below the flats of fully seamed MR-24 panels when the tool body is laid across the seams and rotated so that the hinge points are at the lowest point on the tube. 
     The fact that the bodies can slide on the bar allows the hooks to be placed at various intervals along the length of the bar. A series of holes  26  are drilled through at least one wall of the bar, and the carrier assembly  12  has a latch mechanism which releasably engages any of the holes. The latch mechanism includes a U-shaped bracket  28  whose arms are welded to the body, an a T-shaped pin  30  which extends through a hole  32  in the bracket and an aligned hole  34  in the body. A compression spring  36  is disposed on the pin, between the bottom surface of the bracket, and a shoulder  38  on the pin. The spring urges the pin toward the bar, so it snaps into a hole  26  in the bar when that hole is aligned with holes  32  and  34 . One releases the pin from the bar by pulling up on the handle  40 . 
     The seam clamping tangs referred to above are short U-channel-shaped metal pieces attached near the center of the tube and spaced just far enough apart to straddle the machine-formed portion of the MR-24 and VRS panel seams. 
     The tool is particularly useful for lifting the flat portion of the up-slope roof panels above the plane of the roof, so that a worker to can slide an internally flanged curb diverter plate “D” beneath a roof panel, as suggested in FIG.  3 . The process, illustrated in FIGS. 4-7, is described below. 
     After a hole has been cut in the roof, the curb installation tool is placed across the roof panel seams just over the upslope edge of the hole. The tool is oriented with the hooks  18  facing the down slope direction and the clamping tangs  14  facing perpendicularly up from the roof plane. The bar is placed with the clamping tangs above a roof panel seam, one on either side of the seam. 
     The hooks  18  are allowed to hang downward from the tool body, with their ends extending underneath the edges of the roof panels. The carrier assemblies  12  are then moved along the tool body, if necessary, to desired lifting spots on the panel edges. 
     With the hooks now engaged under the roof panels (FIG.  4 ), the bar is rolled (FIG. 5) in an upslope direction one-quarter turn. This rotation draws the hooks upward, and the hooks lift the flat portions of the panels as a consequence. The clamping tangs pass downward, as the bar is turned, on either side of the roof seam “S” over which they have been centered, and come to rest (FIG. 6) against the tops of the metal panels. Now a locking pliers “P” (FIGS. 3 and 6) is attached tightly to the roof panel seam, holding the clamping tangs down against the panels, thus keeping the tool body from rotating back to its initial position. The tool is left in the rotated position until the diverter plate has been properly positioned under the roof panels. 
     After the diverter plate has been inserted under the roof panel edge, the locking pliers may be removed from the panel seam and the curb installation tool is allowed to rotate back to its original position. The hooks are then slid out from between the roof panels and the diverter plate, and the curb installation tool is removed. 
     Since the invention is subject to modifications and variations, it is intended that the foregoing description and the accompanying drawings shall be interpreted as only illustrative of the invention defined by the following claims.