Method of fabricating toroidal coils

Purpose: To increase the strength in the coil joints, as well as improve the efficiency in the joining work. Method: A coil conductor applied with coupling joint working such as welding or brazing is at first taken up over a stand-by take up rod of a small winding diameter. Then, the coil conductor is taken up by way of a plurality of guide rollers around the core of toroidal coil element in such a way that its radius of curvature is just opposite to the above and its winding diameter is increased. Tension and compression are repeatedly applied in this course to the annealed coupling portion to thereby increase the strength therein. (Ikeda, J.)