| 摘要 |
PURPOSE:To enable the shape and the dimension of a curved part to be uniformly controlled, thereby to decrease the dispersion of the configuration of a product, by transferring a molding drum toward the direction which meets at a right angle the plane including a curved direction of a molding drum. CONSTITUTION:Both side ends of a straight pipe like glass bulb 1 are supported by chucks 2 and 2, while, at the same time, the central part of this bulb 1 to be curved is heated by using a burner or the like then softened. Next, this molding drum 4 is made to come in contact with the upper peripheral surface of the center part to be curved, by advancing the molding drum 4 with a column shape or a cylindrical shape from the side direction which meets at right angle the direction of the pipe axis of the glass bulb 1. Then mold 6 having a guide part 5 is made to face it. Then the central curved part is formed, by turning and moving the chucks 2 and 2 upward, and then by bending the bulb 1 to U-shape to form the central curved part 7. Next, the molding drum is pulled out sideward from the central curved part of the bulb 1. |
