Retaining Tab for Standing-Seam Trays on Wood or Wood-Derivative Carriers

Abstract

In roof covering systems using zinc or zinc-alloy trays with standing-seam crimping, the use of tabs secured by two screws is well known. The invention particularly relates to a metal fastening tab for securing a standing-seam tray on a wood or wood-derivative carrier, which comprises a first surface ( 1 ) with a perforation ( 2 ) for receiving a screw for attachment onto the carrier, a second surface ( 3 ) generally perpendicular to said first surface and including a hook ( 4 ) for engaging with the ridge of the tray to be secured, the two surfaces defining an edge ( 5 ), characterised in that the first surface includes a single perforation ( 2 ) for receiving a single screw, and in that the centre ( 6 ) of said perforation ( 2 ) is not included in the mediator ( 7 ) of the edge ( 5 ) in order to reduce the force applied on the tab and on the tray by the torque induced when tightening said screw. Such a tab, with a single large-diameter screw, is easier and quicker to place than traditional tabs. The tab is specially designed to limit its own torsion and to avoid any buckling of the tray to be secured when tightening the single screw.

1 - 6 . (canceled) 
     
     
         7 . A metal fastening tab for securing a standing-seam tray on a support made of wood or wood derivative, comprising
 a first surface having a perforation configured to receive a screw for fastening onto the support,   a second surface generally perpendicular to said first surface, the second surface including a hook configured to engage with an edge of the tray to be secured, the first surface and the second surface defining a line of intersection of length L,   wherein the perforation of the first surface is a single perforation configured to receive a single screw and wherein the center of the perforation does not lie on the mid-perpendicular to the line of intersection, thereby reducing the force felt on the tab and on the tray by the torque caused when the screw is being tightened.   
     
     
         8 . The tab of  claim 7 , wherein the center of the perforation lies off-center by a distance D greater than 10% of L in relation to the mid-perpendicular to the line of intersection thereby reducing the force felt on the tab and on the tray by the torque caused when the screw is being tightened. 
     
     
         9 . The tab of  claim 7 , wherein reinforcements produced by stamping are provided along the line of intersection. 
     
     
         10 . The tab of  claim 7 , wherein the perforation for receiving the screw for fastening to the support is provided with a surround. 
     
     
         11 . The tab of  claim 10 , wherein said surround has an opening angle of greater than 100°. 
     
     
         12 . The tab of  claim 7 , produced by stamping a sheet of AISI 304 stainless steel.