METHOD FOR BENDING TUBES AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely process for bending tubes. SUBSTANCE: at bending tube with filler due to using flexible mandrel creating pressure acting upon tube at adjusting flexible mandrel members in the form of flexible tie rods with wedges and slit ring. Pressure value is determined according to relationship given in claims of description of invention. Apparatus for performing the method includes bending unit in the form of stationary and rolling around bending rollers; flexible mandrel in the form of elastic rod with slit rings put on it and mutually spaced by means of elastic spacers. Flexible tie rods with wedges are passed through upper portions of slit rings. Wedges of one tie rod are turned to one side and wedges of other tie rod are turned to opposite side with possibility of engaging with slits of slit rings. Each side of flexible tie rods is joined with adjusting studs and with springs arranged in lids. EFFECT: enhanced quality of bent tubes due to possibility of adjusting pressure at bending tubes. 3 cl, 4 dwg, 1 ex