Abstract:
An improved steel stud wall panel which includes a diagonal member able to be placed under tension during installation. The diagonal tension imparts rigidity to the wall panel, preventing warp.

Description:
RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. No. 62/068,820, filed 27 Oct. 2014, the contents of which are here incorporated by reference. 
    
    
     GOVERNMENT INTEREST 
     None 
     BACKGROUND 
     To construct a building, it is known in the art to build a wall as a frame having a horizontal sill plate on the bottom and a horizontal top plate on the top, connected by a series of vertical studs. These components had for decades been made of wood. More recently, light weight steel has been adopted for this. 
     Such wall panels may be cost-effectively pre-assembled in a manufacturing facility and shipped to a building site for a comparatively rapid final assembly. Pre-fabricated wall frames, however, must be moved, and moving may torque the wall frame and distort its shape. Thus, pre-fabricated wall frames should be stabilized against torsional and other stress to maintain the wall panel shape. This is typically done by welding to the wall panel at least one tensioned steel strap running diagonally across a face of the wall frame. This is shown in  FIG. 1 , which shows the bottom portion of a wall panel having a base plate [ 2 ], a plurality of vertical steel studs [ 6 ] and/or shearwall posts [ 1 ] placed in a baseplate notch [ 3 ]. A diagonal strap(s) [ 4 ] is tack-welded [ 5 ] to the base of the shearwall post [ 1 ]. The diagonal strap is installed under tension using a standard steel strap tensioning tool and welded in place. 
     This prior art construct stabilizes the pre-fabricated wall panel during transit and installation. After installation, however, when load is placed on the wall panel, the load may be greater than the tension on the strap, causing the strap to lack tension; when this happens, the steel strap may buckle outward from the wall panel, damaging the gypsum or other wall panel covering. 
     To remedy such strap buckling, the skilled artisan currently cuts the welded strap from the installed wall panel, re-sets the strap and re-welds it to the wall panel in situ at the building construction site. This process, however, is time-consuming, and thus is both expensive and frustrates one of the advantages of pre-fabricated construction: the ability to construct a building quickly. There is thus a need in the art for a way to stabilize pre-fabricated wall panels for shipping, while avoiding the need to remove and re-weld stabilizing straps. We have found a way. 
     BRIEF DESCRIPTION 
     Our invention entails an improved stabilizing strap having an integral tensioning means, whereby a strap installed on a wall panel may be tensioned as needed without disconnecting the strap from the wall panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a typical prior art configuration. 
         FIG. 2  shows an example of our adjustable shearwall assembly, elevation and plan views. 
         FIG. 3  shows a detailed view of an exemplary adjustment mechanism, side, top, section and isometric views. 
         FIG. 4  shows another example of our adjustable shearwall assemply, elevation and plan views. 
     
    
    
     DETAILED DESCRIPTION 
     Our invention may be easily understood by looking at  FIG. 2 , which shows one example of our system. 
       FIG. 2  shows an elevation view of the bottom portion of a prefabricated steel stud wall panel. The panel has a base plate [ 2 ] bearing a vertical shearwall post [ 1 ] and a plurality of vertical studs [ 6 ]. 
     Attached to one of the vertical members is a first diagonal member [ 4   b ]. We prefer the first diagonal member [ 4   b ] be a flat steel strap. One could alternatively use a strap made of other material (e.g., nylon), but this may complicate fire code compliance testing etc. One could also use a steel cable, rod or other member with a significant depth. Doing so, however, would require cutting notches or holes in each of the vertical studs [ 6 ] to accommodate the diagonal member, complicating the fabrication process and reducing the theoretical load bearing capacity of each vertical stud [ 6 ]. 
     We prefer to attach the first diagonal member [ 4   b ] to a shearwall post [ 1 ] because a post [ 1 ] provides greater structural strength than does a stud [ 6 ]. We prefer to attach [ 5 ] the first diagonal member [ 4   b ] by a weld. One could alternatively use fasteners (e.g., sheet metal screws) or an adhesive. 
     Attached to the upper portion of another vertical member (not shown) is a second diagonal member [ 4   a].    
     The second diagonal member [ 4   a ] and first diagonal member [ 4   b ] are adjustably joined by a joint [ 7 ]. The joint [ 7 ] is adjustable and thus allows an installation mechanic to increase tension on the diagonal members [ 4   a ,  4   b ] after the wall panel has been installed. 
     An example of an adjustable joint is shown in  FIG. 3 . The joint may be readily made from two pieces of conventional C channel steel [ 7   a ,  7   b ] connected by at least one bolt [ 7   c ]. The exemplary joint illustrated in  FIG. 3  uses four bolts [ 7   c ] (and appurtenant washers and nuts). One may use more or less bolts as appropriate; it may be least expensive to fabricate and install this kind of joint using only one bolt sited at or near the center of the face of the C channel. The steel C channel [ 7   a ,  7   b ] may be reinforced with a block [ 7   d ] to prevent the bolts from pulling through the face of the C channel. The steel C channel may, alternatively or in addition, be reinforced with a flange [ 7   e ] to maintain the C channel in its proper intended conformation. One may (as illustrated) use a nut to anchor the bolt [ 7   c ]. Alternatively, one may thread a hole(s) in the reinforcing block [ 7   d ] and screw the bolt directly into the block, eliminating the need for a nut. Similarly, if the C channel stock has appropriate strength, one may thread a hole in the C channel and screw the bolt directly into the C channel. The two halves of the join [ 7   a ,  7   b ] are separated by a gap [ 9 ] for adjustment; we have found a gap of roughly 1″ works well. 
     One may alternatively use another type of adjustable joint. For example, if one fashions the diagonal members [ 4   a ,  4   b ] from cable rather than strap, then one may use a turnbuckle as the joint [ 7 ]. Similarly, if one fashions the diagonal members [ 4   a ,  4   b ] from nylon webbing, then one may use a conventional ratchet-type strap tightening clasp, e.g., a Kiln Case Tightener, commercially available from Paragon industries, Inc., Mesquite Tex. The critical requirement is that the joint must be sufficiently adjustable to take up any undesirable slack in the diagonal members [ 4   a ,  4   b ] after installation. 
     One may alternatively dispense with the second diagonal member [ 4   a ]. To do so, one can attach one end [ 7   a ] of the adjustable joint [ 7 ] directly to the baseplate [ 2 ], a shearwall post [ 1 ] or a stud [ 6 ]. If this approach is taken, we prefer to attach to a post [ 1 ], and further prefer the attachment incorporate a gusset plate [ 8 ] as shown in  FIG. 4 . We prefer the gusset plate [ 8 ] be attached to both the baseplate [ 2 ] and post [ 1 ] (as exemplified in  FIG. 4 ). 
     Given our disclosure, the artisan will readily arrive at alternatives. We thus intend the legal coverage of our invention to be defined by the appended legal claims and their permissible equivalents, rather than by the specific example illustrated here.