| 摘要 |
PURPOSE:To restrict a flattening of pipe and a generation of folds, and to control the pipe flattening and a decreasing degree of the wall thickness of pipe, by arranging tops, equipped with elastic cushioning materials, opposingly to each other on both sides of a pipe axis, and providing forces, in the radial directions of the pipe, to the tops by pressing-force-transmitting members. CONSTITUTION:A device for prevneting the flattening of a pipe is assembled from tops 7 each of which has an elastic cushioning material 8 attached to its outside, mandrels 9 which have truncated-conical-frustum shapes and are connected to each other by connecting connecting-rods 10 with the aids of pins, and reaction-receiving frames 15 used for supporting the mandrels 9 and the tops 7 movably in the radial direction of the pipe, etc.; the device is inserted into the pipe P. When a pressure is applied to the mandrel 9 in the pipe P by an external force such as a hydraulic jack 13, the tops 7 are expanded to the direction of the pipe wall by a wedge action of the mandrel 9 because the movement of the top 7 in the longitudinal direction of the pipe P is restricted, so the gap between the inner wall of the pipe P and the outer surface of the device is closed. The pipe is bent in this state. After the bending work, the device is easily taken out of the pipe by releasing the force of the jack 13. |
