Abstract: A machine for continuously forming square tubes includes, in sequence, forming stations suitable for progressively bending a sheet strip, at least one finishing station suitable for further approaching the edges of the bent sheet strip for the final welding and at least one station for closing the square tube. In a forming station, the axes of rotation of the lower rolls of each pair of forming rolls are horizontal and aligned to each other. Each finishing station includes an idle forming roll placed below the square tube being formed; two idle forming rolls, placed at the sides of the square tube being formed, performing movements in opposite directions, parallel to the plane of the sheet strip and two idle forming rolls placed above the square tube being formed, performing movements orthogonal to the plane of the sheet strip.

Abstract: A machine for continuously forming square tubes includes, in sequence, forming stations suitable for progressively bending a sheet strip, at least one finishing station suitable for further approaching the edges of the bent sheet strip for the final welding and at least one station for closing the square tube. In a forming station, the axes of rotation of the lower rolls of each pair of forming rolls are horizontal and aligned to each other. Each finishing station includes an idle forming roll placed below the square tube being formed; two idle forming rolls, placed at the sides of the square tube being formed, performing movements in opposite directions, parallel to the plane of the sheet strip and two idle forming rolls placed above the square tube being formed, performing movements orthogonal to the plane of the sheet strip.