Patent ID: 8100312

Claim:
A machine ( 31 ) for continuously forming square tubes ( 32 ), comprising in sequence: at least one forming station ( 33 ) configured for progressively bending a sheet strip ( 34 ); at least one finishing station ( 35 ) configured for further approaching edges ( 36 ) of the bent sheet strip ( 34 ); and at least one welding station of the square tube ( 32 ), wherein: each forming station ( 33 ) comprises two pairs of motorized forming rolls ( 1 , 2 ; 3 , 4 ; 5 , 6 ; 7 , 8 ; 9 , 10 ), mounted onto axes ( 45 ) parallel to a plane of the sheet strip ( 34 ), which are facing each other and are configured to perform movements parallel to the plane of the sheet strip ( 34 ), upper rolls ( 1 , 3 , 5 , 7 , 9 ) of each pair ( 1 , 2 ; 3 , 4 ; 5 , 6 ; 7 , 8 ; 9 , 10 ) being configured to perform movements parallel and/or orthogonal to the plane of the sheet strip ( 34 ), each finishing station ( 35 ) comprises at least one idle forming roll ( 12 ; 16 ; 20 ) placed below the square tube ( 32 ) being formed; two idle forming rolls ( 11 ; 15 ; 19 ), placed at sides of the square tube ( 32 ) being formed, which perform movements parallel to the plane of the sheet strip ( 34 ), and two idle forming rolls ( 13 , 14 ; 17 , 18 ; 21 , 22 ), placed above the square tube ( 32 ) being formed, configured to perform movements orthogonal to the plane of the sheet strip ( 34 ).