Roof panel assemblies for forming weatherproof standing seam joints and the like and methods of joining standing seam roof panels
BACKGROUND OF THE INVENTION 
     The present invention relates to standing seam roof constructions of the type used on various buildings, for example, on rectangular metal buildings which have spaced beam members arranged to form a roof having a ridge at the longitudinal centerline thereof, and spaced purlins spanning the beams to which the roof panels are secured. 
     Various methods of erecting such standing seam roof structures, and various roof panel assemblies such as those of the type illustrated in U.S. Pat. Nos. 4,168,596 and 4,106,250 have been proposed and various panel systems such as shown in U.S. Pat. Nos. 4,155,209; 3,535,844; and 3,667,180 have employed factory applied mastic as a water-proofing material. None of these prior constructions, however, have the combined attributes of the standing seam roof panel assemblies which presently will be described. 
     The present panel assembly incorporates matching mastic or &#34;hot melt&#34; material beads on the upstanding panel seaming edges, which may be applied at the factory in a predetermined bead volume along a protected pocket located interjacent the ends of each of the upstanding seaming edges in a predetermined location. 
     One of the prime objects of the present invention is to design a panel structure in which pairs of adjacent panel sheets, having upstanding mating seams adapted to be locked in a standing seam are so designed that the roof seaming operation which deforms the assembly extrudes the flowable mating mastic or &#34;hot melt&#34; material strips which have been applied to the panels at the factory into even the most minute crevices between the mating seams, to provide a completely water-tight joint. 
     Another of the prime objects of the invention is to provide the mastic or &#34;hot melt&#34; material in the form of continuous, longitudinal beads deposited in communicating, mating, seam pockets which protects the mastic during shipment of the panels from the factory to the job site in bundles. 
     The invention contemplates placement of the mastic in an optimum protected position on the upstanding seam edges in a manner such that the generally upstanding seam edges can slide against each other during transportation and erection of the roof panels without dislodging or damaging the mastic, the complemental mastic masses coming in contact only when the cap is installed and the cap and seaming edges are deformed during the seaming operation. 
     Still another object of the present invention is to provide a structure which can be used at a three or four corner panel intersection point to provide a water-tight structure and also at the ridge joint to provide a water-proof ridge joint. 
     The invention contemplates incorporation of the complementing mastic beads in the adjacent standing seam edges to be mated at a location below any notches which are made at three or four corner laps or elsewhere. 
     Still another object of the invention is to provide an assembly and method of the character described wherein mastic-to-panel adhesion and mastic-to-mastic cohesion are assured because of the manner in which the mastic beads are disposed in complementary relation in the seam edges to be mated and then squeezed during the seaming operation. 
     A further object of the invention is to provide a standing seam roof panel assembly of the character described which is easy and economical to erect, and can be easily and reliably unitized in the field, using a relatively simple seaming apparatus to perform the edge seaming operation. 
     Still another object of the invention is to minimize the necessity of the field application of gun grade mastic which may be inadvertently misapplied, or not applied at all, during the erection of the building. 
     Still a further object of the invention is to design a symmetric roof panel of the character described which will readily nest with like panels when bowed slightly to &#34;open&#34; it up, the construction lending it to an economical form of shipment in which the panels are strapped in a nested stack. 
     SUMMARY OF THE INVENTION 
     A prefabricated roof panel assembly for forming standing seam roofs and the like, wherein a pair of upstanding seam forming interlocking mating edges on adjacent sheets are each formed with opposed complementary pockets substantially the same distance down from their upper ends. Mastic or &#34;hot melt&#34; beads of predetermined volume are disposed in the pocket in each wall section, and squeezed into spaces between the seaming edges when the pockets are deformed during the seaming operation in which the seam edges are united in locked relation. 
    
    
     Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, wherein: 
     FIG. 1 is a fragmentary top plan view showing identical roof panels of the present design locked to one another by the standing seams which are formed; 
     FIG. 2 is an enlarged, exploded, fragmentary, transverse, sectional view illustrating a manner in which the roof panels can be secured to the roof purlins; 
     FIGS. 3-5 are greatly enlarged, fragmentary cross-sectional views taken at a point intermediate the clip assemblies shown in FIG. 2, illustrating the method of seaming the panel edges in progressive steps; and 
     FIG. 6 is a similar view taken at one of the clip assemblies. 
    
    
     Referring now more particularly to FIG. 1 of the drawings, adjacent panels 9, 10 and 11 are shown assembled with their mating edges forming standing seams, generally designated S as shown. Metal clip assemblies A (FIG. 2) can be employed in a manner to be later described to secure the adjacent panels to the roof purlins P in any acceptable manner, such as by bolting the clip assemblies in place. 
     As FIG. 3 indicates, the adjacent upstanding seam forming adjacent edges of the elongate panels 10 and 11, which are generally designated 10a and 11a respectively, are provided with generally matching complementing opposed pocket-forming portions 12 for receiving factory applied mastic or &#34;hot melt&#34; material beads 15 which extend the full length of the panels. The &#34;hot melt&#34; material can be the synthetic resin manufactured by H. B. Fuller Company of Minneapolis, Minnesota, U.S.A., and applied to the metal roof panels in a &#34;hot&#34; state, i.e. 350° F. The material has excellent cold temperature flexibility. The panel edges also include reversely, bent downwardly extending portions 10b and 11b, which are connected with the portions 10a and 11a by curvilinear portions 10c and 11c, and formed with upturned edges 10d and 11d. 
     A generally U-shaped cap, generally designated C, is provided in enveloping relationship with the upper ends of the panel edges, and has lower flanges 14 which, as will become apparent, are snap-fitted under the portions 10d and 11d to begin with. 
     To complete the seaming operation, forces are applied by the seaming machine in the lateral directions &#34;x&#34; and &#34;y&#34; to the cap C seam edge portions 10b and 11b, and the pocket sections 12 in a squeezing operation which distributes the beads 12 in the manner indicated in FIG. 5. With the curvature of the pockets 12 now deformed, as at 12&#39; (FIG. 5), so that they substantially engage at &#34;z&#34;, mastic fills the spaces between the adjacent edges 10a and 11a both above and below the &#34;z&#34; area, and is further squeezed up into the area 15a at the top of the joint between the upper end of the cap C and the portions 10c and 11c of the panel seaming edges. 
     It will be observed, from an inspection of FIGS. 4 and 5, that the cap C, when assembled in the FIG. 4 condition, has spaces 16 between the cap top and the bridging sections 10c and 11c to permit the deformation which is shown in FIG. 5, and that, when the completed standing seam joint S is formed, as shown in FIG. 5, the cap side portions are in tight engagement with the portions 10c and 11c and the downturned walls 10b and 11b, over their length. When assembled by the method indicated, a completely waterproof joint is provided which will withstand even extreme weather conditions. 
     FIG. 2 illustrates a typical clip assembly A such as, for instance, may be used to tie the standing seams S to the purlins P at spaced intervals along the seams S. Here, the metal tie strip 17 has tabs 17a and 17b which are bent reversely to envelop panel edge portions 10c, 10b and 11c, 11b. The lower end of the tie strip 17 extends through an opening 18 provided in base clip part 19 and is provided with retainer loops 17c. Fig. 2 is an exploded view taken before cap assembly and seaming have taken place and is illustrative only of a construction which could be used. When the seaming operation takes place, the strip 17 is also encapsulated by the mastic and, as previously indicated, the mating seam edges are locked and prevented from separating to the extent that the mastic delaminates or fractures during the life of the roof structure when subjected to normal conditions such as expansion and contraction, heat and cold cycles, and the like. The clip assemblies A may be used at approximately two foot intervals. Because opposing mastic pockets were provided, a seal on both sides of the member 17 automatically occurs. 
     It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.