Method and apparatus for working peripheral wall of hemispherical shell

DETAILED DESCRIPTION An object of the present invention is to provide a working method for eliminating defects produced in conventionally working pressure resisting shells and for spherically finishing the inner peripheral wall of a hemispherical shell to minimize the wall thickness of the shell, resulting in the provision of a light weight pressure resisting shell and a compact and economical vessel.
According to the method of the present invention for achieving this object, a method is proposed in which the inner peripheral wall of the hemispherical shell formed on some portions of the inner and outer peripheral walls with projections, is worked by one process for working portions of said inner peripheral walls not formed with said projections in rotating said hemispherical shell about the symmetrical axis of said shell and by another process for working said projections with said hemispherical shell being fixed.
Thus, by the method according to the present invention, the inner peripheral wall of the hemispherical shell can be cut after thick metal fittings have previously been welded to said hemispherical shell so that it can be finished spherically to the working accuracy of a machine tool without being affected by later applied welding stress.
As a result, since the wall thickness of the hemispherical shell can be minimized, a light weight pressure resisting shell and thus a compact and economical abyssal diving research vessel can be provided.
According to the present invention, a profile surfacing apparatus is provided for profiling the inner or outer surface of said hemispherical shell to any curved surfaces.
To achieve this object, said surfacing apparatus comprises an apparatus body mounted on a boring head of a boring machine, a rotary flange rotatably supported by said apparatus body while receiving the rotational drive force of a main spindle of the boring machine, a rotary arm provided on an end of this rotary flange andd having a slidable guide section consisting of a slide groove and a slide bore portion in the direction perpendicular to a shaft of said rotary flange, a cutting tool holder provided with a slide head slidable along said slide guide section of the rotary arm and a cutting tool and provided on said slide head slidably parallel to the axis of said rotary flange and a profiling unit subjected to the profiling movement in the directions of cutting and cutting feeding said cutting tool along a template mounted to said rotary arm