Seam plate for retaining roof decking membrane

Abstract

A stress plate or seam plate for use in connection with securing membrane sheets to underlying roofing decking substructure comprises a circular disk having a central aperture for receiving a screw fastener. A plurality of concentric ribs are defined between the central aperture and the peripheral edge of the plate for providing reinforcing and bending or flexibility characteristics to the stress plate or seam plate, and in accordance with the principles and teachings of the present invention, a plurality of circumferentially spaced, downwardly extending projections having substantially V-shaped cross-sectional configurations are provided upon the underside of the seam or stress plate so as to engage the membrane sheets and retain the same at their desired locations upon the underlying roofing deck substructural assembly. Contrary to conventional stress plates having sharp-pointed prongs or tangs, the projections of the present invention have substantially rounded or radiused apices so as not to puncture or rupture the membrane sheets.

What is claimed as new and desired to be protected by Letters Patent of the United States of America, is:  
     
         1 . A seam plate for securing a membrane sheet to an underlying substructure, comprising: 
 a circular plate;    an aperture defined within a central portion of said circular plate for receiving a fastener for securing said circular plate to an underlying substructure; and    a plurality of projections extending downwardly from said circular plate for engaging a membrane sheet so as to effectively secure the membrane sheet to the underlying substructure when said circular plate is fixedly secured to the underlying substructure by the fastener,    each one of said plurality of downwardly extending projections having a rounded engagement portion for engaging the membrane sheet so as to effectively secure the membrane sheet to the underlying substructure without piercing the membrane sheet so as not to cause tearing and rupture of the membrane sheet.    
     
     
         2 . The seam plate as set forth in  claim 1 , wherein: 
 each one of said plurality of downwardly extending projections has a substantially V-shaped cross-sectional configuration, and said rounded engagement portion of said downwardly extending projection comprises a radiused apex portion of said substantially V-shaped projection.    
     
     
         3 . The seam plate as set forth in  claim 2 , wherein: 
 each one of said substantially V-shaped projections comprises a pair of sides with an included angle defined at said apex portion of 90°.    
     
     
         4 . The seam plate as set forth in  claim 2 , wherein: 
 each one of said substantially V-shaped projections is severed from said circular plate along longitudinal circumferentially extending sides thereof and are integrally attached to said circular plate along longitudinal circumferentially separated ends thereof.    
     
     
         5 . The seam plate as set forth in  claim 1 , wherein: 
 a plurality of radially inner and radially outer upwardly and downwardly extending annular rib members are provided upon said seam plate in order to provide said seam plate with reinforcing and flexibility characteristics.    
     
     
         6 . The seam plate as set forth in  claim 5 , wherein: 
 said plurality of downwardly extending projections are arranged within circular arrays substantially coincident with said radially inner and radially outer downwardly extending annular rib members.    
     
     
         7 . The seam plate as set forth in  claim 6 , wherein: 
 a first radially inner circular array of said downwardly extending projections comprises six projections equiangularly spaced from each other; and    a second radially outer circular array of said downwardly extending projections comprises eight projections equiangularly spaced from each other.    
     
     
         8 . The seam plate as set forth in  claim 5 , wherein: 
 said plurality of radially inner and radially outer upwardly and downwardly extending annular rib members have substantially sinusoidal configurations.    
     
     
         9 . A seam plate for securing a membrane sheet to an underlying roofing decking substructure, comprising: 
 a circular plate;    an aperture defined within a central portion of said circular plate for receiving a fastener for securing said circular plate to an underlying roofing decking substructure; and    a plurality of projections extending downwardly from said circular plate for engaging a membrane sheet so as to effectively secure the membrane sheet to the underlying roofing decking substructure when said circular plate is fixedly secured to the underlying roofing decking substructure by the fastener,    each one of said plurality of downwardly extending projections having a rounded engagement portion for engaging the membrane sheet so as to effectively secure the membrane sheet to the underlying roofing decking substructure without piercing the membrane sheet so as not to cause tearing and rupture of the membrane sheet under wind uplift conditions.    
     
     
         10 . The seam plate as set forth in  claim 9 , wherein: 
 each one of said plurality of downwardly extending projections has a substantially V-shaped cross-sectional configuration, and said rounded engagement portion of said downwardly extending projection comprises a radiused apex portion of said substantially V-shaped projection.    
     
     
         11 . The seam plate as set forth in  claim 10 , wherein: 
 each one of said substantially V-shaped projections comprises a pair of sides with an included angle defined at said apex portion of 90°.    
     
     
         12 . The seam plate as set forth in  claim 10 , wherein: 
 each one of said substantially V-shaped projections is severed from said circular plate along longitudinal circumferentially extending sides thereof and are integrally attached to said circular plate along longitudinal circumferentially separated ends thereof.    
     
     
         13 . The seam plate as set forth in  claim 9 , wherein: 
 a plurality of radially inner and radially outer upwardly and downwardly extending annular rib members are provided upon said seam plate in order to provide said seam plate with reinforcing and flexibility characteristics.    
     
     
         14 . The seam plate as set forth in  claim 13 , wherein: 
 said plurality of downwardly extending projections are arranged within circular arrays substantially coincident with said radially inner and radially outer downwardly extending annular rib members.    
     
     
         15 . The seam plate as set forth in  claim 14 , wherein: 
 a first radially inner circular array of said downwardly extending projections comprises six projections equiangularly spaced from each other; and    a second radially outer circular array of said downwardly extending projections comprises eight projections equiangularly spaced from each other.    
     
     
         16 . The seam plate as set forth in  claim 13 , wherein: 
 said plurality of radially inner and radially outer upwardly and downwardly extending annular rib members have substantially sinusoidal configurations.    
     
     
         17 . The seam plate as set forth in  claim 9 , wherein: 
 said circular plate has an outer peripheral edge portion which is inclined upwardly at a predetermined angle with respect to a horizontal plane such that said outer peripheral edge portion does not puncture and tear the membrane sheet under wind uplift conditions.    
     
     
         18 . In combination, a roofing decking substructure assembly, comprising: 
 a roofing decking substructure;    a first membrane sheet having a first end portion which is adapted to be secured atop said roofing decking substructure;    a second membrane sheet having a second end portion which is adapted to be overlapped and secured to said first end portion of said first membrane sheet so as to form a seamed connection with said first membrane sheet;    a seam plate for securing said first end portion of said first membrane to said roofing decking substructure; and    a fastener for securing said seam plate to said roofing decking substructure;    said seam plate comprising a circular plate; an aperture defined within a central portion of said circular plate for receiving said fastener for securing said circular plate to said roofing decking substructure; and a plurality of projections extending downwardly from said circular plate for engaging said first end portion of said first membrane sheet so as to effectively secure said first membrane sheet to said roofing decking substructure when said circular plate is fixedly secured to said roofing decking substructure by said fastener, each one of said plurality of downwardly extending projections having a rounded engagement portion for engaging said first end portion of said first membrane sheet so as to effectively secure said first end portion of said first membrane sheet to said roofing decking substructure without piercing said first end portion of said first membrane sheet so as not to cause tearing and rupture of said first membrane sheet under wind uplift conditions.    
     
     
         19 . The combination as set forth in  claim 18 , wherein: 
 each one of said plurality of downwardly extending projections has a substantially V-shaped cross-sectional configuration, and said rounded engagement portion of said downwardly extending projection comprises a radiused apex portion of said substantially V-shaped projection.    
     
     
         20 . The combination as set forth in  claim 19 , wherein: 
 each one of said substantially V-shaped projections comprises a pair of sides with an included angle defined at said apex portion of 90°.    
     
     
         21 . The combination as set forth in  claim 19 , wherein: 
 each one of said substantially V-shaped projections is severed from said circular plate along longitudinal circumferentially extending sides thereof and are integrally attached to said circular plate along longitudinal circumferentially separated ends thereof.    
     
     
         22 . The combination as set forth in  claim 18 , wherein: 
 a plurality of radially inner and radially outer upwardly and downwardly extending annular rib members are provided upon said circular plate in order to provide said circular plate with reinforcing and flexibility characteristics.    
     
     
         23 . The combination as set forth in  claim 22 , wherein: 
 said plurality of downwardly extending projections are arranged within circular arrays substantially coincident with said radially inner and radially outer downwardly extending annular rib members.    
     
     
         24 . The combination as set forth in  claim 23 , wherein: 
 a first radially inner circular array of said downwardly extending projections comprises six projections equiangularly spaced from each other; and    a second radially outer circular array of said downwardly extending projections comprises eight projections equiangularly spaced from each other.    
     
     
         25 . The combination as set forth in  claim 22 , wherein: 
 said plurality of radially inner and radially outer upwardly and downwardly extending annular rib members have substantially sinusoidal configurations.    
     
     
         26 . The combination as set forth in  claim 18 , wherein: 
 said circular plate has an outer peripheral edge portion which is inclined upwardly at a predetermined angle with respect to a horizontal plane such that said outer peripheral edge portion does not puncture and tear the membrane sheet under wind uplift conditions.