| 摘要 |
PURPOSE:To enhance the working ability of bevelling of a spherical shell composing a spherical tank, by providing such an arrangement that, after a reference line and a locus line are marked on a bed having a concave spherical surface, upon bevelling of the spherical surface, rails are laid along the four sides of the spherical shell, and a bevelling machine is set on these rails. CONSTITUTION:Upon working, two reference lines X-X, Y-Y which are orthogonal together are marked on the surface of a bed 2 having a concave spherical surface with a radius of curvature which is larger than, by a predetermined length, the radius of curvature of a spherical shell 1 that are formed by press- working an aluminium plate to be worked. Then, using the cross point G of both reference lines as the original point, locus points P used to determine the positions where rails 4 on which a self-travelling type bevelling machine 3 travels, are set. With the use of the locus points P as a reference, the rails 4 are arranged along the four side outer periphery of the spherical shell 1 by means of a support 6, and the spherical surface 1 is disposed within an area surrounded by the rails 4, through a support 7. Thereafter, the four sides of the spherical shell 1 is subjected to the working of bevelling by a milling cutter in a working machine. |
