APPARATUS FOR MAKING TUBES WITH MULTIPLE HELICAL CORRUGATIONS Russian patent published in 1995 - IPC

FIELD: metal working. SUBSTANCE: apparatus includes a mandrel, having a variable cross section in the form of cylindrical supporting part and a working part with two cross rows of profiled rollers, mounted with possibility of rotation in such a way, that an equatorial cross sections of rollers, arranged in the row, being the nearest to the supporting part, are arranged longitudinally in the same plane as their axis and equatorial cross sections of the rollers, mounted in the row, being far from the supporting part, are arranged with an inclination relative to the axis. The apparatus also has discs, mounted relative to the axis of the mandrel by the same fashion as the rollers between the dents of the mandrel. EFFECT: enhanced structure of the apparatus. 1 cl, 3 dwg