Mechanical roof fastener

A penetrating, fastening and sealing device for both mechanically securing a flexible elastomeric sheet to the upper surface of a roof, and sealingly engaging said sheet, said device including:

• (a) a rigid lower retainer having a bottom surface and an upper surface, said upper surface being formed with a hole and an upstanding central boss surrounding said hole, said boss having an internally threaded surface, and a plurality of annular concentric alternating grooves and ridges formed in said upper surface and extending about the central boss;
• (b) anchoring means for securing the lower retainer to the upper surface of the roof;
• (c) a rigid upper retainer having a bottom surface and an upper surface and formed with a central hole, said bottom surface having a plurality of annular concentric alternating grooves and ridges extending concentrically about the central hole, said grooves and ridges of the upper retainer being located within respective ridges and grooves formed on the top surface of the lower retainer to provide a series of alternating annular gripping zones and unloading zones for the elastomeric sheet secured therebetween;
• (d) separate fastener means extending through the hole formed in the upper retainer and engaged with the internally threaded surface of the lower retainer for drawing said retainers against each other to sealingly secure the elastomeric sheet between the cooperating ridges and grooves of said retainers to provide said alternating zones, said fastener means having a threaded shaft and a frangible upper portion which separates from the fastener means upon a certain sealing force being exerted against the elastomeric sheet;
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• (e) cutting means for cutting an aperture in the elastomeric sheet for passage of the fastener means therethrough for drawing the retainers against each other, said cutting means comprising a sharp annular edge located on an edge of the threaded shaft of the fastener means.

A method of mechanically securing a flexible elastomeric sheet to the upper surface of a roof via the use of a plurality of spaced fastening devices, each of said fastening devices includes a base plate and a top plate with each of said plates having a series of annular concentric alternative grooves and ridges extending about a central opening formed in each of the plates;

• a central opening formed in the top plate and a threaded boss on the base plate surrounding the central opening;
• and a fastener having a threaded shaft terminating in a sharp annular cutting edge and a frangible upper portion;
• said method comprising the steps of:
• (a) anchoring a plurality of the base plates at spaced locations to the upper surface of the roof;
• (b) spreading the flexible elastomeric sheet over the roof upper surface and anchored base plates;
• (c) placing a top plate on the elastomeric sheet above the threaded boss of each of the base plates;
• (d) inserting the threaded shaft through the central opening of the top plate and into engagement with the elastomeric sheet;
• (e) piercing the elastomeric sheet above the threaded boss with the cutting edge of the shaft to form an aperture in the sheet;
• and
• (f) securing the top plate to the anchored base plate by rotatably advancing the threaded fastener through the central opening in the top plate and through the sheet aperture and into engagement with the threaded boss to draw the top plate toward the base plate until the frangible portion of the fastening means separates therefrom with the annular grooves of the top and base plates cooperating with each other to clamp and secure the elastomeric sheets therebetween at a plurality of annular gripping zones.

A penetrating, fastening and sealing device for both mechanically securing a flexible elastomeric sheet to the upper surface of a roof, and sealingly engaging said sheet, said device including:

• (a) a rigid lower retainer having a bottom surface with a plurality of radially extending stiffening ribs formed thereon and an upper surface, said upper surface being formed with a hole and an upstanding central boss surrounding said hole, said boss having an internally threaded surface, and a plurality of annular concentric alternating grooves and ridges formed in said upper surface and extending about the central boss;
• (b) anchoring means for securing the lower retainer to the upper surface of the roof;
• (c) a rigid upper retainer having a bottom surface and an upper surface and formed with a central hole, said bottom surface having a plurality of annular concentric alternating grooves and ridges extending concentrically about the central hole, said grooves and ridges being located within respective ridges and grooves formed on the top surface of the lower retainer to provide a series of alternating annular gripping zones and unloading zones for the elastomeric sheet secured therebetween;
• and
• (d) separate fastener means extending through the hole formed in the upper retainer and engaged with the internally threaded surface of the lower retainer for drawing said retainers against each other to sealingly secure the elastomeric sheet between the cooperating ridges and grooves of said retainers to provide said alternating zones, said fastener means having a frangible upper portion which separates from the fastener means upon a certain sealing force being exerted against the elastomeric sheet.

A penetrating, fastening and sealing device for both mechanically securing a flexible elastomeric sheet to the upper surface of a roof, and sealingly engaging said sheet, said device including:

• (a) a rigid lower retainer having a cylindrical downturned peripheral end wall and a bottom surface and an upper surface, said upper surface being formed with a hole and an upstanding central boss surrounding said hole, said boss having an internally threaded surface, and a plurality of annular concentric alternating grooves and ridges formed in said upper surface and extending about the central boss;
• (b) anchoring means for securing the lower retainer to the upper surface of the roof;
• (c) a rigid upper retainer terminating in an annular downturned peripheral edge and having a bottom surface and an upper surface formed with a central hole, said bottom surface having a plurality of annular concentric alternating grooves and ridges extending concentrically about the central hole, said grooves and ridges being located within respective ridges and grooves formed on the top surface of the lower retainer to provide a series of alternating annular gripping zones and unloading zones for the elastomeric sheet secured therebetween, and with said peripheral edge of the upper overlying and being located radially beyond the peripheral end wall of the lower retainer;
• and
• (d) separate fastener means extending through the hole formed in the upper retainer and engaged with the internally threaded surface of the lower retainer for drawing said retainers against each other to sealingly secure the elastomeric sheet between the cooperating ridges and grooves of said retainers to provide said alternating zones, said fastener means having a frangible upper portion which separates from the fastener means upon a certain sealing force being exerted against the elastomeric sheet.

A mechanical fastener for securing a flexible elastomeric sheet to the upper surface of a roof;

• said fastener including:
• (a) a base plate adapted to be secured to the upper surface of the roof and underlie the elastomeric sheet, said base plate being formed with a series of annular grooves and intervening ridges in a top surface thereof;
• (b) anchoring means for securing the base plate to the upper surface of the roof;
• (c) an opposed top plate mounted on the base plate for placing and maintaining the elastomeric sheet located therebetween in a sealingly secured relationship, said top plate being formed with a series of annular grooves and intervening ridges in a bottom surface thereof, said grooves having smooth concave surfaces in cross section with said ridges having smooth convex surfaces in cross section with smaller radii of curvature than that of the grooves, said ridges of each of the plates compressing the elastomeric sheet against areas of adjacent grooves of the respective opposite plates to form a series of concentric annular zones of compression with alternating annular zones of greater and reduced sealing pressure, said zones of greater sealing pressure being located at the area of engagement of the ridges with the respective grooves;
• and
• (d) fastener means for securing the top plate on the base plate in the sealingly secured relationship.