Abstract: The present invention can provide a method and an apparatus for bending a pipe whose bending cross section has reduced compressed ratio, reduced reduction ratio of area and reduced reduction in thickness and in which bending can be conducted at the desired curvature. In the present invention, both edges of the pipe bending portion are arrested and grasped, a center of one bending edge is set to be the axis and a revolution axis is amounted on it, a rotation axis is mounted at a center of the other bending edge and gears are installed on the revolution axis and the rotation axis so as to engage each other so that the driving is driven to the gear on the rotation axis. The rotation axis revolves having the radius to be the distance from the rotation axis to the revolution axis and at the same time the rotation axis rotates on its axis having the radius of the gear in response to the revolution angle.

Abstract: In a method and apparatus for manufacturing a corrugated tube, a tube is clamped by a pair of spaced apart chucks. A local portion of the tube is softened. The chucks are moved in the same direction such that the trailing or rearward chuck moves farther than the leading or forward chuck, thereby imparting an axially compressive force on the tube. Accordingly, a bulge is formed at the softened portion of the tube. The heating and compression cycle may be performed several times to obtain a corrugated tube having a plurality of bulges or waves formed therein.