Tube bending device

Claim 1

Apparatus for bending thin walled tubing, comprising: an annular induction heating coil having an axis disposed in a first plane; an annular fluid spray cooling coil disposed adjacent said heating coil and having an axis disposed in a second plane and means for directing a coolant fluid toward the space surrounded by said cooling coil closely adjacent said second plane; means for positioning a tube to be bent so that said tube extends longitudinally through said coils with the portion of said tube corresponding to the outer side of the bend to be made disposed at a clearance distance A from the adjacent inner surface of the heating coil, and the portion of said tube corresponding to the inner side of the bend to be made disposed at a greater clearance distance B from the adjacent inner surface of the heating coil, the ratio A:B being in the range of about 0.4 to 0.9; means for pushing said tube through said coils in the direction extending from said heating coil toward said cooling coil; means for holding and bending said tube upon emergence thereof from said coils; said second plane being inclined at an angle between about 3° and 10° with respect to said first plane, said planes intersecting along a line passing through the region partially surrounded by the bend of said tube, whereby said tube to be bent is heated in a wedge-shaped annular zone prior to bending thereof, thus providing a smooth and continuous bend of said tube.