Method and device for bending a cylindrical tube or the like

Apparatus for bending a tube (1) in such a manner that two consecutive segments (2, 3) of the tube make a non-zero angle a of given value between each other, the apparatus comprising, relative to a reference base (55):

• a device (30) for making in the wall (4) of the tube (1) a wave (20) projecting outwards from the wall of the tube, said projecting wave being defined between two flanks (22, 23) forming a non-zero angle b between each other and centered substantially on the plane (21) of separation between the two segments,
• the device comprising a chamber (31) defined inside the tube and centered substantially on said plane (21) of separation and at least two jaws (33, 34) forming between them a dihedral angle substantially of said non-zero value b, said jaws being mounted to co-operate with the outside face of the wall (4) of the tube (1) to guide formation of the wave;
• and
• means (50) for imparting permanent plastic deformation to said wave (20) until the given value is obtained for the angle a between the two segments (2, 3), wherein the means (50) for imparting plastic deformation comprises means (51) for moving at least one (34) of the two jaws (33, 34) relative to the other jaw.

Apparatus for bending a tube (1) in such a manner that two consecutive segments (2, 3) of the tube make a non-zero angle a of given value between each other, the apparatus comprising, relative to a reference base (55):

• means (30) for making in the wall (4) of the tube (1) a wave (20) projecting outwards from the wall of the tube all around the wall of the tube, said projecting wave being defined between two flanks (22, 23) forming a nonzero angle b between each other and centered substantially on the plane (21) of separation between the two segments;
• and
• means (50) for imparting permanent plastic deformation to said wave (20) until the given value is obtained for the angle a between the two segments (2, 3),
• wherein the means (30) for making in the wall (4) of the tube (1) a projecting wave (20) defined between two flanks (22, 23) forming a nonzero angle b between each other and centered substantially on the plane (21) of separation between the two segments, are constituted by:
• a solid oblong-section wheel (40);
• means (41) for holding said solid wheel (40) inside the tube;
• at least two jaws (33, 34) forming between them a dihedral angle substantially of the non-zero value b, said jaws being mounted to co-operate with the outside face of the wall (4) of the tube to guide formation of the wave (2);
• and
• means (42) for moving the solid wheel (40) in translation and in rotation relative to the tube while imparting a force thereto so as to press the wheel against the inside face of the wall (4) of the tube to deform it in creep so as to obtain said wave (20).