| 摘要 |
PURPOSE:To manufacture an annular body without requiring independent bending of end part and without using a bending roll by holding both ends of a plate, bending them to draw near to each other, turning them around specified points, and joining both end parts. CONSTITUTION:Both end parts of a plate 20 are held by the first and second clamping devices 21, 22. When a switch for arm rotation in a switch box 30 is operated, the first arm 23 and the second arm 24 are turned. The steel plate 20 is turned in the direction to draw both ends near to each other around the centers of rotation of the first arm 23 and second arm 24, and bent while being guided so as to come into contact to outer periphery of a guide member 26. Meanwhile, the guide member 26 is lowered as shown by the arrow 71 by its own weight. When the work is completed, both end parts of the steel plate 20 are joined together, and a truely circular annular body that follows the shape of outer periphery of the guide member 26. |
