Abstract:
A roof attachment system has a stud for retaining a fixture to a roof and is mountable to and sealable with a roof. The attachment system includes a base and a retaining stud which projects upwardly from the base. A membrane is disposed over the base. Cooperative upper and lower mount plates include peripheral oppositely projecting teeth which form an intermediate axial gap. A retainer ring is disposed in into the gap and alternately engages against the teeth of the upper and lower mount plates to axially tighten the attachment components to provide a seal.

Description:
BACKGROUND 
       [0001]    This disclosure relates to roofing assemblies, and more particularly, to a roofing assembly for efficiently securing a roofing membrane and mounting and attaching an object to a roof structure, while effectively distributing the object load and maintaining a failsafe fluid seal. 
         [0002]    Many fastening systems and components exist for securing a membrane to a roof structure. Most notably, seam plates are disposed at predetermined positions over a fluid sealing roof membrane and attached to the underlying roofing substructure via driving a securing member or heat sealing. Additional systems exist for mounting and attaching objects over the roof/membrane structure. However, known attachment systems are often unsuitable for attachment of heavy objects such as large scale solar panels because the assembly or roof substructure is unable to support the mass of the panels when concentrated over a relatively small area or would require too numerous points of attachment to be feasible in practice. Many known systems increase risk of fluid breaching the building at the point of attachment with the roofing membrane. There is a need for a roof attachment system which effectively distributes weight on a roof over a large area, while maintaining an effective and failsafe seal with a roofing membrane. 
       SUMMARY 
       [0003]    Briefly stated, a roof attachment system in a preferred form comprises a base having an axial retaining stud and defining a plurality of attachment holes. A membrane is disposed over the base. A lower mount plate is disposed over the membrane and coaxial about the stud. The lower mount plate has a plurality of upperwardly and radially outwardly projecting teeth at its periphery. An upper mount plate is disposed over the lower mount plate and is also coaxial about the retaining stud. The upper mount plate has a plurality of downwardly and radially outwardly projecting teeth at its periphery. The upper and lower teeth are spaced so that upon mating, the upper teeth extend below the lower teeth to define a gap. A retaining ring is disposed in the gap and alternately engages the upper and lower teeth to axially tighten the lower mount plate, the upper mount plate, the membrane and the base to provide a fluid tight seal. 
         [0004]    The retaining stud is preferably threaded and the lower mount plate and the upper mount plate are threaded to the stud. The retaining ring is split to form adjacent split portions. A connector connects the split portions. The retaining ring is dimensioned and formed of a material which results in a failure rate greater than that of the base, the upper mount plate and the lower mount plate. The retaining ring preferably has a wave-like shape wherein the retaining ring has alternating peaks and valleys. 
         [0005]    The base and the retaining stud are integral in one embodiment. The base has a central frustoconical shoulder. At least one of the base, the lower mount plate and the upper mount plate has a plastic composition. 
         [0006]    A roof attachment installation comprises a roofing substructure. A base has a central axial retaining stud and is affixed to the roofing substructure. A membrane is disposed over the base and the roofing substructure. A lower mount plate is disposed over the membrane and coaxial about the stud. The lower mount plate has a plurality of upwardly and radially outwardly projecting teeth. An upper mount plate is disposed over the lower mount plate and coaxial about the stud. The upper mount plate has a plurality of downwardly and radially outwardly projecting teeth. The upper and lower teeth are spaced so that upon mating, the upper teeth axially extend below the lower teeth to define a gap. A retaining ring is disposed in the gap and alternately engages the upper and lower teeth to axially tighten the lower mount plate, the upper mount plate, the membrane and the base to provide a fluid tight seal. 
         [0007]    The base and the retaining stud are preferably integral. The base defines a plurality of holes. Fasteners extend through the holes to affix the base to the roofing substructure. The retaining ring is a wave-like structure comprising alternating peaks and valleys. The retaining ring is preferably split to form adjacent split end portions. A connector connects the split end portions. 
         [0008]    The base, the lower mount plate, the upper mount plate and the retaining ring preferably have a plastic composition. The retaining stud in one embodiment has a threaded portion. The upper mount plate and the lower mount plate each have a central threaded opening which threadably engages the retaining stud. The retaining ring is dimensioned and is formed of a material which results of a failure rate greater than that of the base, the upper mount plate and the lower mount plate. The base further may have a central frustoconical shoulder adjacent a lower portion of the retaining stud. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a roof attachment system; 
           [0010]      FIG. 2  is a sectional view of the attachment assembly of  FIG. 1 ; 
           [0011]      FIG. 3  is a sectional view of the disclosed attachment system with the mount assembly partially assembled; 
           [0012]      FIG. 4  is a sectional view of the disclosed attachment system; and 
           [0013]      FIG. 5  is an enlarged perspective view of a retainer ring that may be employed in the roof attachment system. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    With reference to the drawings wherein the following numerals represent like parts throughout the several figures, an attachment system for load distribution and failsafe sealing on a roofing structure is generally designated by the numeral  10 . 
         [0015]    The disclosed system includes a wide base  22 , which may be formed of plastic or another relatively lightweight, strong and rigid material. The retaining stud or bolt  18  is molded into the plastic base, although other known techniques for attachment may be employed. The retaining stud  18  functions as a principal support and attachment structure for an object to be mounted to the roof. 
         [0016]    As shown, the base  22  includes numerous attachment holes  24  and preferably extends over a large area. A preferred embodiment includes a base  22  with a diameter of approximately 14 inches, although the particular diameter is clearly non-limiting. The base  22  may be attached to a roofing substructure by driving securing members (i.e., nails or screws) through the holes. The holes  24  are disposed at predetermined positions so as to align with the crest portions of a standard corrugated roof substructure. Usually a substrate (i.e., insulation) is positioned between the base  22  and the substructure. 
         [0017]    Once a base  22  or numerous bases are secured on the roofing structure, the fluid sealing membrane  20  may be laid over the base. With reference to  FIG. 2 , a lower mount plate  12  is positioned over the membrane  20 , thereby cooperating with the base  22  and mount stud  18  to pinch the membrane  20 . As depicted, the lower mount plate  12  has a generally circular cross section with a central opening and a plurality of upward and radially outwardly projecting teeth  13  spaced along its periphery. 
         [0018]    An upper mount plate  14  substantially mates with the lower plate  12 . The upper plate  14  has also has a generally circular cross section and a central opening and includes a plurality of downward and radially outwardly projecting teeth  15  spaced along its periphery. The respective teeth  13  and  15  of the upper and lower plates are spaced to allow the upper plate teeth to extend axially below the lower plate teeth with an axial gap  17  therebetween when the upper and lower plates are mated (shown best in  FIG. 2 ). The central openings of the plates may be threaded. The upward and downward extensions of the teeth  13  and  15  are preferably at an angle to the central axis. 
         [0019]    In one embodiment, the outer surface of the mounting stud  18  is threaded and the upper and lower mount plates  12  and  14  are secured via threaded mating with the stud  18 . The respective plates  12  and  14  are coaxial about the stud  18 . 
         [0020]    With reference to  FIGS. 4 and 5 , a retaining ring  16  is positioned axially between the upper plate teeth  15  and the lower plate teeth  13 . As shown in  FIG. 5 , the retaining ring  16  may have a modified wave formation with peaks and valleys which aid in engaging with the teeth. The retaining ring typically has a split  17  to allow engagement around the mount plates. One embodiment includes a locking mechanism, such as a clip  19 , at end portions adjacent the split to allow the ring  16  to be locked after attachment. Once engaged between the teeth and locked, the retaining ring  16  may be rotated over the approximate radius of a single tooth so that the crests or peaks align with the lower plate teeth (which extend axially upward) and the valleys align with the upper plate teeth (which extend axially downward). Rotation of the retaining ring  16  in this manner tightens the axial abutment between each element, thereby forming a strong fluid seal within the attachment system. 
         [0021]    As shown, the installed attachment system includes four separate fluid tight sealed interfaces: upper plate/stud shoulder; lower plate/stud; upper plate/lower plate surface; and lower plate/membrane surface. Preferably, the retaining ring  16  is formed of a material and thickness having strength to be the engineered first failure point of the system. Thus, if the ring fails, the numerous sealing interfaces remain unharmed until a new retaining ring  16  can be installed, thereby preserving the integrity of the seal of the roof structure. Additionally, the disclosed system provides a fluid seal without requiring welding or similar attachment of the membrane and without utilization of multiple membranes. 
         [0022]    In addition to the large base  22  distributing a downward force from the attached object and/or snow, attachment of the base to the roofing substructure in this fashion helps distributes uplift force (from wind or the like) over numerous crests in the roofing substructure. The mount stud may be configured with a bolt or like unit which can be reciprocated axially therealong to adjust the height of the attached structure. 
         [0023]    The base  22  is typically manufactured from a material such as plastic to reduce manufacturing cost, but this material is in no way limiting of the system. 
         [0024]    The lower mount plate  12 , upper mount plate  14  and retaining ring  16  may also have a plastic composition. Several base/mount units may be installed as described above for supporting large heavy items, such as high powered solar panels. When installed on the attachment system, the force from the large mass of the solar panels is distributed over the entire area of the large base  22 , rather than concentrated centrally near the stud as would be the case with related known mounting units. This is an important consideration in that the integrity and effectiveness of roofing insulation substrates may be compromised if compressed. 
         [0025]    In sum, the disclosed system attachment  10  increases the number of attachment points to the roofing substructure (and thus the holding power of the unit to the roofing substructure) and the footprint to distribute mass and resulting downward force on the roof substrate. For example, an installation of four 3 foot by 5.5 foot solar panels connected to each other via hinged attachment on adjacent edges in an “accordion style” can be attached and maintained in a pitched configuration on a roof using nine spaced attachment systems like those disclosed herein, the preferred diameter of a base being approximately 14 inches. 
         [0026]    While preferred embodiments of the foregoing roof attachment system have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modification adaptations and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present invention.