Abstract: A glass tube bending apparatus according to the present invention includes a drum for bending a heated/softened glass tube into a circular shape, a first driving device, coupled to the drum, for moving the drum straight, and a second driving device, coupled to the drum, for rotating the drum in a direction, and a control for independently controlling the rotating speed and the moving speed of the drum. According to this apparatus, the operation speeds of rotating and moving of the drum can be controlled independently. Therefore, distortion of glass tubes can be decreased, and thermal bending of tubes can be performed with high precision. Further, various sorts of glass tubes can be treated. Still further, since the first driving device and the second driving device are operated in synchronism, the precision of the thermal bending of glass tubes is enhanced.

Abstract: An apparatus for bending a glass tube to a U shape having a pair of chucks for holding the glass tube at both sides, a heating device for heating and softening the glass tube held by the chucks at the predetermined zone for bending, and a turning mechanism for the chucks. The turning centers of the turning mechanism are set each at positions located at a predetermined distance inwardly from an axis of the unbent glass tube held by the chucks. The distance between the turning centers is less than the distance between the axes of straight zones of the glass tube formed after bending. There is also a bending drum for guiding bending, which drum moves forwardly and backwardly into and away from the predetermined zone for bending of the glass tube.