Abstract:
A thermal clip arrangement for a roof panel system, such as a standing seam roof system, wherein the thermal clip arrangement includes a non-metallic anchor block which holds a slideable metal clip.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority from U.S. Provisional Patent Application Ser. No. 60/488,044, filed on Jul. 16, 2003.  
       FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to roof systems and arrangements included therewith that stabilize roofs, e.g., by providing wind uplift resistance.  
       BACKGROUND OF THE INVENTION  
       [0003]     Typically, among the challenges that need to be addressed in providing a standing seam roof system or the like, and panel clips or the like therefor, are: thermal conductivity (as particularly regards “cold spots”, the likelihood of energy loss, and meeting building codes); wind uplift resistance; and available room for panel clips to slide in response to typical (thermal or mechanical) stress deformations.  
         [0004]     To meet these demands and more, Star Building Systems of Oklahoma City, Okla., currently manufactures the “STARSHIELD” standing seam roof system, which involves the use of a unique metal panel clip of a two-piece cooperative sliding design which accommodates, e.g., thermal expansion. Such a clip is shown ( 100 ) in perspective view in  FIG. 1 , wherein a sliding tab  102  is mounted on a main clip body  104  at a slot  106  which permits sliding motion of the tab  102  with respect to the main clip body  104 . The clip  100  is also shown in elevational view in  FIG. 2  mounted between a roof panel  110  and Z-purlin  112 . Both figures (and, especially, the arrows) help develop an appreciation for the stresses normally assumed by a panel clip, particularly, in connection with wind uplift (and analogous mechanical stresses) and with thermal expansion.  
         [0005]     Other conventional metal roof clips for roof panel arrangements are widely disclosed, such as in the following U.S. Pat. No. 6,470,644 to James et al.; U.S. Pat. No. 5,911,663 to Eidson; U.S. Pat. No. 5,697,197 to Simpson; U.S. Pat. No. 5,222,341 to Watkins et al.; and U.S. Pat. No. 4,543,760 to Barker et al. These patents as well as the brochure, “The Starshield Standing Seam Roof System,” identified as brochure no. PDS-SSRS-600 as published by Star Building Systems, include useful background information on standing seam roof systems in general.  
         [0006]     However, a need has been recognized in connection with providing panel clips and related components that address the aforementioned challenges, and more, in improved fashion.  
       SUMMARY OF THE INVENTION  
       [0007]     In accordance with at least one presently preferred embodiment of the present invention, there is broadly contemplated a thermal clip system involving a non-metallic anchor block which holds a slideable metal clip.  
         [0008]     Generally, there is broadly contemplated in accordance with at least one presently preferred embodiment of the present invention a roof clip arrangement comprising: a tab portion for attachment to roof cladding; and an anchor portion; the tab portion being slidably mounted with respect to the anchor portion; the anchor portion having a coefficient of thermal conductivity less than that of metals. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The present invention and its presently preferred embodiments will be better understood by way of reference to the detailed disclosure herebelow and to the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a perspective view of a conventional roof clip;  
         [0011]      FIG. 2  is an elevational view of a conventional roof clip integrated with roofing;  
         [0012]      FIG. 3  is a perspective view of a roof clip;  
         [0013]      FIG. 4  is a essentially the same view as  FIG. 3 , but with the sliding tab shown in a different position;  
         [0014]      FIGS. 5A and 5B  are orthogonally distinct elevational views of a roof clip integrated into a Z-purlin roofing arrangement;  
         [0015]      FIGS. 6A and 6B  are orthogonally distinct elevational views of a roof clip integrated into an open web purlin.  
         [0016]      FIG. 7  is a graphical illustration of Z-purlin rotation under load. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     The patents mentioned heretofore, as well as the brochure, “The Starshield Standing Seam Roof System,” identified as brochure no. PDS-SSRS-600 as published by Star Building Systems, include useful background information on standing seam roof systems in general.  
         [0018]     Typically, panel clips are formed entirely from metal, as is the case with the current Star Building Systems panel clip mentioned above (and as shown in  FIGS. 1 and 2 ). However, it has been recognized that the use of a non-metallic material, as evidenced by the conductivity table provided below, can present a substantial reduction in thermal conductivity that may be of great assistance in the context of a roofing system.  
                                             Conductivity Table                                    Gold   172.0           Steel   26.2           Brick, fired   0.58           Wood, oak   0.102           Plastic foam   0.16                      
 
 (Conductivity [K]; Btu/Hr/ft 2 /F on 1″ thick homogeneous material) 
 
         [0020]     Though plastic foam is mentioned above, it should be appreciated that the following materials are in particular presently contemplated for use in a panel clip, in accordance with at least one presently preferred embodiment of the present invention, are: PVC (polyvinyl chloride); CPVC (chlorinated polyvinyl chloride); nylon; polypropylene; LEXAN (polycarbonate); or any of a wide variety of possible composites involving plastic or polymeric materials. For instance, there are also contemplated a wide variety of reground or recycled materials that are at least partly polymeric or plastic. Essentially any such materials may conceivably be employed, providing the thermal conductivity is low and other desired physical specifications are met (e.g., having little or no propensity for heat and UV-degradation).  
         [0021]     A perspective view of a roof clip in accordance with a preferred embodiment of the present invention is shown in  FIG. 3 . As shown, there may preferably be provided a plastic or polymeric main body (or anchor block  204 ) as well as a sliding metal tab portion. The sliding metal tab portion  202  will preferably serve to attach to roof cladding, much as would a conventional metal clip. The sliding metal tab portion  202  may be formed and configured in essentially any suitable manner, but may preferably be formed from light gauge (such as 26-gauge or 29-gauge) stainless steel. A viable alternative to light gauge stainless steel, among others, would be galvanized steel with a zinc or zinc/aluminum coating. The possibilities for fabricating a panel clip main body or anchor block in accordance with at least one presently preferred embodiment of the present invention are wide and varied, and include: molding; screw injection molding; extrusion; pulltrusion; and NC machining. Also shown are center guides  214 , to be described more fully below.  
         [0022]      FIG. 4  is a perspective view of an anchor block with the metallic tab  202  having been slid outwards into a different position. It will be appreciated by those of ordinary skill in the art that such sliding action is needed to accommodate thermal expansion and contraction in the greater roofing arrangement, while the attendant low friction between the plastic or polymeric anchor block and the metallic tab body will be of immense practical benefit in extending the service life of the thermal clip in general. Sliding action here is essentially unlimited, which can provide tremendous advantages.  
         [0023]     Though there is essentially illustrated and contemplated a solid, basically monolithic body for use as an anchor block  204 , it should be appreciated that a vast number of analogously functioning structures may also be employed. For instance, a beehive or honeycomb type structure, having essentially the same outer cross-section but a differing internal configuration, may be employed. Essentially any external or internal configuration is conceivable, provided that the resultant management of stress flow is optimized so as not to abjectly compromise structural integrity or overall performance under load.  
         [0024]      FIGS. 5A and 5B  provide more detailed elevational views of essentially the same concept as in  FIG. 3 , but with additional peripheral components illustrated. ( FIG. 5B  provides an elevational view from an orthogonally distinct direction with respect to  FIG. 5A .) As shown, a non-metallic anchor block  204  may be affixed to the Z-purlin or open web purlin ( 212 ) of a roofing arrangement via one or more suitable anchor fasteners  216 . The sliding tab  202  is preferably attached to a roof panel  210  in conventional manner (e.g., via crimping) along a seam  218 . One or more fastener guides (or center guides)  214  are preferably provided to facilitate the insertion and centering of the anchor fastener(s)  216 . As shown, the anchor fasteners  216  could preferably be embodied by two #12-14 self-drilling (SD) screws. Sliding tab  202  will also preferably have “notches” (e.g., of a part-circular shape) that will integrate with center guides  214  such that an unimpeded volumetric (e.g., cylindrical) space is created from top to bottom when the tab  202  itself is properly centered or aligned. This will thus allow for minor movements of tab  202 , as may occur during shipment, to be corrected when assembly of a roof structure takes place; the assembler will need only slide the tab  202  until the notches are properly aligned with the center guides  214 .  
         [0025]     Preferably, the outer cross-section of block  204  may be asymmetrical via a protrusive foot portion  219  as shown, which can increase the bearing area for gravity load while providing an optional locus of attachment for fasteners  216 .  
         [0026]     It should be appreciated that the shapes and configurations illustrated in  FIGS. 3-5B , have been found to be particularly favorable in terms of fulfilling the desired objectives, including, but not limited to, spatial accommodation with respect to the roof panel (such that a large surface portion of the anchor block is disposed essentially directly adjacent the material of the roof panel), and the “T-slot” configuration via which the sliding tab is slidably mounted with respect to the anchor block. It will further be appreciated that the illustrated “T-slot” configuration and sliding tab can provide for more extensive contact between the sliding tab and roof panel so as to impart greater strength and integrity to the roof panel structure both when essentially stationary or when sliding due to, e.g., thermal expansion.  
         [0027]      FIGS. 6A and 6B  illustrate essentially the same concept as in  FIGS. 5A and 5B , but in the context of an open web purlin arrangement. Components in  FIGS. 6A and 6B  similar to those found in  FIGS. 5A and 5B  bear reference numerals advanced by 100. Dimensions a and b, provided solely for illustrative purposes, could be 6″ and 8″, respectively, thus illustrating the admirable physical coverage that can easily be provided by a relatively small anchor block ( 304 ). In this instance, center guides  314  and fasteners  316  are spaced apart proportionately greater than in the embodiment of  FIGS. 5A and 5B .  
         [0028]      FIG. 7  graphically illustrates Z-purlin rotation under load. As shown, under load a Z-purlin may displace by an essentially horizontal distance dx and an essentially vertical distance dy. Also, an essentially vertical leg portion, providing a major portion of the strength and integrity of the Z-purlin, may displace angularly over a rotational angle b. It will be appreciated that in the presence of significant displacements dx, dy and b, such as in response to thermal stress, the physical stress on the Z-purlin will have the potential to negatively impact surrounding components to which the Z-purlin is attached. However, in the presence of a thermal clip as broadly contemplated herein, it will be appreciated that thermal stress will indeed be reduced and, as a result, will result in much less structural displacement dx, dy and b, thus helping preserve the structural integrity of the Z-purlin and the components connected therewith.  
         [0029]     In brief summary, among the features and benefits provided by a panel clip in accordance with at least one presently preferred embodiment of the present invention are: 
        the elimination of a thermal short between the roof cladding and building structure, along with the associated energy efficiency and elimination of “cold spots”;     a longer tab length, which reduces local stress concentration, thereby distributing load over a larger area, and increases wind up-lift capacity;     a (preferably) 26 gauge tab which requires less power during a seaming process, leads to essentially no seam bulging and no corrosion, and lends itself to a stronger tab and longer service life;     a non-metallic body for holding the sliding tab that leads to freer sliding, less resistance to binding, and less force accumulation in the attendant mutual contact;     stabilization of Z-purlin rotation under load; and     a reduction in sound transmission.        
 
         [0036]     If not otherwise stated herein, it may be assumed that all components and/or processes described heretofore may, if appropriate, be considered to be interchangeable with similar components and/or processes disclosed elsewhere in the specification, unless an express indication is made to the contrary.  
         [0037]     If not otherwise stated herein, any and all patents, patent publications, articles and other printed publications discussed or mentioned herein are hereby incorporated by reference as if set forth in their entirety herein.  
         [0038]     This application claims priority from U.S. Provisional Patent Application Ser. No. 60/488,044, filed on Jul. 16, 2003, which is hereby incorporated by reference as if set forth in its entirety herein.  
         [0039]     It should be appreciated that the apparatus and method of the present invention may be configured and conducted as appropriate for any context at hand. The embodiments described above are to be considered in all respects only as illustrative and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.