Abstract: The machine for the formation of tubes includes at least, in series with each other, forming stations including pairs of idle rollers which make rototranslational movements of the same amplitude but in opposite directions, and at least one finishing station including four idle rollers having a concave profile with a constant curvature and able to perform rototranslational movements of the same amplitude and direction according to 90° axes. The lower rollers of each forming station have an elliptical profile with a curvature decreasing form the outer edge to the inner edge of the roller. The upper rollers of the first forming station have an elliptical profile with a curvature increasing from the outer edge to the inner edge of the roller; the upper rollers of the forming stations subsequent to the first have a circular profile.

Abstract: A finishing station of variable structure includes two plates, joined integrally to each other and able to slide along two vertical shoulders which support a plurality of forming rollers mounted on shoes able to slide in radial guides formed in the plates. The shoes that support the forming rollers are moved by levers hinged to the plates and connected to each other by connecting rods, two of which are hinged to levers hinged to the plates and secured to the ground. A further forming roller, situated in the lower part of the plates, is preferably secured to the ground. In the inner part of the two forming rollers situated in the upper part of the finishing station a disc blade is formed to control the position of the edges of the bent strip of sheet metal during the finishing operation.

Abstract: The machine for the formation of tubes includes at least, in series with each other, forming stations including pairs of idle rollers which make rototranslational movements of the same amplitude but in opposite directions, and at least one finishing station including four idle rollers having a concave profile with a constant curvature and able to perform rototranslational movements of the same amplitude and direction according to 90° axes. The lower rollers of each forming station have an elliptical profile with a curvature decreasing form the outer edge to the inner edge of the roller. The upper rollers of the first forming station have an elliptical profile with a curvature increasing from the outer edge to the inner edge of the roller; the upper rollers of the forming stations subsequent to the first have a circular profile.

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.

Abstract: A finishing station of variable structure includes two plates, joined integrally to each other and able to slide along two vertical shoulders which support a plurality of forming rollers mounted on shoes able to slide in radial guides formed in the plates. The shoes that support the forming rollers are moved by levers hinged to the plates and connected to each other by connecting rods, two of which are hinged to levers hinged to the plates and secured to the ground. A further forming roller, situated in the lower part of the plates, is preferably secured to the ground. In the inner part of the two forming rollers situated in the upper part of the finishing station a disc blade is formed to control the position of the edges of the bent strip of sheet metal during the finishing operation.

Abstract: A flap wheel (1) for satin finishing systems for pipes or for sheet metal, includes a plurality of radial flaps (2) fixed to the hub (3) of the flap wheel (1) by coupling elements integral with the hub (3) of the flap wheel (1) and inserted in seats (8) formed in each flap (2) near the edge (14) thereof adjacent the hub (3). The hub (3) is advantageously hollow and has, in its inside wall, annular grooves (10) which are identical and parallel each other; the flaps (2) are further connected to the hub (3) by gluing, pouring inside the hub (3) an adhesive which flows out through a plurality of rows of through holes (9) formed in the wall of the hub (3) to coinciding with the annular grooves (10). A method of producing the flap wheel is also described.

Abstract: A system (1) for satin finishing of sheets of metal (4) uses mechanically fixed flap wheels (6), namely flap wheels (6) whose flaps (9) are fixed mechanically to the hub (10) of the flap wheel (6). The system includes at least one satin finishing station (5)—equipped with at least one mechanically fixed flap wheel (6) with a horizontal axis and with a mechanism (7) adapted to make the at least one mechanically fixed flap wheel (6) rotate, and a feed element (8) adapted to feed the sheets of metal (4) longitudinally through the satin finishing stations (5). Advantageously, in order to compensate for the wear on the flaps (9) of the mechanically fixed flap wheels (6) and keep their peripheral speed and their removal pressure constant, the rotation speed of the mechanically fixed flap wheels (6) is increased and the wheels are moved vertically.