Patent attributes
A method for bending a pipe by, while sandwiching one portion of the pipe by a gripping device, sandwiching the other portion of the pipe between a pair of bending rolls and by causing the other bending roll to relatively revolve about one bending roll out of the pair of bending rolls, wherein the bending rolls are held by a common movable frame body, the relative revolution is realized by synchronous movement in which rotating movement for rotating the frame body and lateral movement for moving the frame body in a direction (Y-axis direction) perpendicular to a longitudinal direction (X-axis direction) of the pipe are synchronized with each other, and the movement in the Y-axis direction of the frame body is performed such that a position in the Y-axis direction of a center axis of the one bending roll is held and a position in the X-axis direction of a rotating center point of the rotating movement remains same.