METHOD AND APPARATUS FOR BENDING PIPES Russian patent published in 1994 - IPC

FIELD: metal working. SUBSTANCE: pipes are bent by forcing pipe workpiece through curvilinear die by rotatable roller. Part of the pipe is offset away from the center of bending by moving end of the workpiece on the inner generating line of bending. Mathematical dependence for determining the value of offset is cited in full description of the invention. Apparatus for carrying out the method has pusher member, die, and rotatable roller. The die includes two half-dies with rectilinear and curvilinear passages. Shaped passage of the roller has holder to retain the workpiece on inner generating line of bending. Axis of curvilinear passage is offset relative to the axis of rectilinear passage. Roller is mounted so as to form an intermediate zone whose axis extends at an angle to axes of passages of the half-dies. EFFECT: enhanced efficiency of the method and apparatus. 1 cl, 7 dwg