Hvac duct connection system and flange

Abstract

An HVAC duct section connection system is provided with first and second corner flanges, and at least one self-threading bolt. Both the first corner flange and the second corner flange include first and second legs. The first and second legs having an interior surface and an exterior surface. The exterior surface is disposed opposite the interior surface. The first and second corner flanges each have at least one fastener aperture extending between the interior and the exterior surfaces, the fastener aperture including an integrally formed truncated cone extending out from the exterior surface, wherein the truncated cone has an inner diameter. The self-threading bolt has a shank and a head, the shank having a threaded section with a thread diameter sized to engage the inner diameter of the truncated cone.

What is claimed is: 
     
         1 . An HVAC duct section connection system, comprising:
 a first corner flange and a second corner flange, wherein both the first corner flange and the second corner flange comprise:
 a first leg and a second leg, the first and second legs integrally connected to one another at a respective first end, and each leg extending outwardly away from the respective first end away from the other leg; 
 an interior surface extending along the first and second legs; 
 an exterior surface extending along the first and second legs, the exterior surface disposed opposite the interior surface; 
 at least one fastener aperture extending between the interior surface and the exterior surface, the fastener aperture including an integrally formed truncated cone extending out from the exterior surface, wherein the truncated cone has an inner diameter; and 
   at least one self-threading bolt having a shank and a head, the shank having a threaded section with a thread diameter sized to engage the inner diameter of the truncated cone.   
     
     
         2 . The connection system of  claim 1 , wherein the truncated cones of the first corner flange and the second corner flange comprise plastically deformed material. 
     
     
         3 . The connection system of  claim 2 , wherein the truncated cone comprises at least one slit. 
     
     
         4 . The connection system of  claim 3 , wherein the truncated cone comprises a plurality of slits and a plurality of cone sections, wherein adjacent cone sections are separated from one another by a one of said plurality of slits. 
     
     
         5 . The connection system of  claim 2 , wherein the truncated cone comprises at least one wall failure element. 
     
     
         6 . The connection system of  claim 5 , wherein the truncated cone includes an inner diameter surface, and the at least one wall failure element is disposed in the inner diameter surface. 
     
     
         7 . The connection system of  claim 5 , wherein the truncated cone includes an outer diameter surface, and the at least one wall failure element is disposed in the outer diameter surface. 
     
     
         8 . The connection system of  claim 5 , wherein the truncated cone includes an inner diameter surface and an outer diameter surface, and the at least one wall failure element is a plurality of wall failure elements, and at least one of the wall failure elements is disposed in the inner diameter surface, and at least one of the wall failure elements is disposed in the outer diameter surface. 
     
     
         9 . The connection system of  claim 1 , wherein the shank of the at least one self-threading bolt includes a threaded portion having a first diameter and an unthreaded section having a second diameter, the second diameter is less than the first diameter, the unthreaded section disposed between the threaded section and the head, the first diameter sized so that the threaded portion threadably engages the inner diameter of the truncated cone. 
     
     
         10 . The connection system of  claim 1 , wherein the integrally formed truncated cone has an engagement length that is at least long enough to have two circumferential threads of the threaded section engaged with the truncated cone. 
     
     
         11 . A duct corner flange, comprising:
 a first leg;   a second leg, the first and second legs integrally connected to one another at a respective first end, and each leg extending outwardly away from the respective first end away from the other leg;   an interior surface extending along the first and second legs;   an exterior surface extending along the first and second legs, the exterior surface disposed opposite the interior surface;   at least one fastener aperture extending between the interior surface and the exterior surface, the fastener aperture including an integrally formed truncated cone extending out from the exterior surface, the truncated cone comprising plastically deformed material.   
     
     
         12 . The duct corner flange of  claim 11 , wherein the truncated cone comprises at least one slit. 
     
     
         13 . The duct corner flange of  claim 12 , wherein the truncated cone comprises a plurality of slits and a plurality of cone sections, wherein adjacent cone sections are separated from one another by a one of said plurality of slits. 
     
     
         14 . The duct corner flange of  claim 11 , wherein the truncated cone comprises at least one wall failure element. 
     
     
         15 . The duct corner flange of  claim 14 , wherein the truncated cone includes an inner diameter surface, and the at least one wall failure element is disposed in the inner diameter surface. 
     
     
         16 . The duct corner flange of  claim 14 , wherein the truncated cone includes an outer diameter surface, and the at least one wall failure element is disposed in the outer diameter surface. 
     
     
         17 . The duct corner flange of  claim 14 , wherein the truncated cone includes an inner diameter surface and an outer diameter surface, and the at least one wall failure element is a plurality of wall failure elements, and at least one of the wall failure elements is disposed in the inner diameter surface, and at least one of the wall failure elements is disposed in the outer diameter surface.