Improved roll-formed structural member

Abstract

An elongate roll-formed structural member comprising a pair of generally C-shaped channel elements nested together, the pair of generally C-shaped channel elements forming a body having a substantially rectangular cross-section profile. The body comprising first and second flanges and first and second web portions separating the first and second flanges. The first and second web portions at one or both of the top and/or bottom of the body narrow towards each other and defines a recessed region, adapted for optionally receiving forcing members.

1 . An elongate roll-formed structural member comprising:
 a pair of generally C-shaped channel elements nested together, the pair of generally C-shaped channel elements forming a body having a substantially rectangular cross-section profile, the body comprising:   first and second flanges substantially parallel and spaced apart at a top and bottom of the body respectively, and   first and second web portions separating the first and second flanges, the first and second web portions being substantially parallel and spaced apart at sides respectively, and   wherein the first and second web portions at one or both of the top and/or bottom of the body narrow towards each other and defines a recessed region, and   wherein said structural member further comprises one or more external elongate reinforcing elements configured to be coupled onto the recessed region(s) of the elongate roll-formed structural member.   
     
     
         2 . The elongate roll-formed structural member as claimed  claim 1 , wherein the flange adjacent the recessed region has a flange width less than a width of the space between the first and second web portions. 
     
     
         3 . The elongate roll-formed structural member as claimed in  claim 2 , wherein the flange adjacent the recessed region has a flange width at least less than the widest space between the first and second web portions. 
     
     
         4 . The elongate roll-formed structural member as claimed in  claim 1 , wherein the recessed region is at the uppermost or lowermost ends of the body. 
     
     
         5 . The elongate roll-formed structural member as claimed in  claim 4 , wherein the external reinforcing element(s) coupled onto the recessed region(s) results in a box-section in which the external reinforcing element(s) lie within a general rectangular profile or envelope. 
     
     
         6 . The elongate roll-formed structural member as claimed in  claim 5 , wherein the recessed region comprises a recess width:
 a) between 1 and 5 times a wall thickness of the elongate external reinforcing element, or   b) between 1 and 3 times the wall thickness of the elongate external reinforcing element.   
     
     
         7 . (canceled) 
     
     
         8 . The elongate roll-formed structural member as claimed in  claim 5 , wherein the elongate external reinforcing element(s) coupled to the recessed region form a wall thickness:
 a) between two 2 and six 6 times a wall thickness of the web portions without reinforcement, or   b) between 3 and 5 times the wall thickness of the web portions without reinforcement.   
     
     
         9 . (canceled) 
     
     
         10 . The elongate roll-formed structural member as claimed in  claim 5 , comprising fasteners to couple the external elongate reinforcing element onto the body, the fasteners being one or a combination of screws, rivets, bolts, adhesives, welds. 
     
     
         11 . The elongate roll-formed structural member as claimed in  claim 5 , wherein each elongate external reinforcing element comprises a C-shaped cross-section having a flange-corresponding portion and two web-corresponding portions depending from the flange-corresponding portion, and wherein the two web-corresponding portions of an outermost external elongate reinforcing element do not protrude outward past the widest region of the web portions. 
     
     
         12 .- 14 . (canceled) 
     
     
         15 . The elongate roll-formed structural member as claimed in  claim 5 , wherein the elongate external reinforcing element extends a partial length along the elongate roll-formed member. 
     
     
         16 . The elongate roll-formed structural member as claimed in  claim 5 , wherein two elongate external reinforcing elements are coupled to one or both of the first and second flanges. 
     
     
         17 . The elongate roll-formed structural member as claimed in  claim 5 , wherein at least one elongate external reinforcing element is coupled to both the first and second flanges. 
     
     
         18 . The elongate roll-formed structural member as claimed in  claim 17 , wherein two elongate external reinforcing elements are coupled to each of the first and second flanges. 
     
     
         19 . The elongate roll-formed structural member as claimed in  claim 1 , wherein the first and second webs have indentations in a mid-region extending longitudinally along the elongate roll-formed structural member to improve structural performance of the member. 
     
     
         20 . The elongate roll-formed structural member as claimed in  claim 1 , wherein the body cross-section including the recessed region extends along at least a significant portion of the length of the elongate roll-formed member. 
     
     
         21 . A method of forming an elongate roll-formed structural member comprising:
 providing metal sheets,   bending the metal sheets with rollers to form a pair of generally C-shaped channel elements,   nesting the pair of generally C-shaped channel elements together to form a body having a substantially rectangular cross-section profile, the body comprising:
 first and second flanges substantially parallel and spaced apart at top and bottom of the body respectively, and 
 first and second web portions separating the first and second flanges, the first and second web portions being substantially parallel and spaced apart at respective sides, and 
   bending the metal sheets to form a recessed region where the first and second web portions at one or both of the top and/or bottom of the body narrow towards each other, and   fitting one or more elongate external reinforcing elements with a predetermined length onto one or both of the flanges.   
     
     
         22 . The method of forming an elongate roll-formed structural member as claimed in  claim 21 , further comprising providing fasteners to couple each elongate external reinforcing element onto the flanges. 
     
     
         23 . (canceled) 
     
     
         24 . The method of forming an elongate roll-formed structural member as claimed in  claim 21 , wherein the predetermined length of the elongate external reinforcing elements is less than the length of the body of the elongate roll-formed structural member to reinforce part of the member. 
     
     
         25 . The method of forming an elongate roll-formed structural member as claimed in  claim 21 , further comprising forming indentations extending longitudinally in a mid-region along the elongate roll-formed structural member to improve structural performance of the member. 
     
     
         26 . The method of forming an elongate roll-formed structural member as claimed in  claim 21 , wherein the body cross-section including the recessed region extends along at least a significant portion of the length of the elongate roll-formed member.