摘要：Some characteristics of the open or ring torus such as the three systems of circle sections are pointed out in the article. The torus of this shape is applied in mechanical engineering for designing certain parts of machines. Some machine parts are obtained by the intersection of a surface of revolution and a plane, while some others are obtained by the intersection of surfaces of revolution. The example presented in the article shows how the body of a thrust bar and a pipe diverging which consist of a cylinder and a torus are created. The article emphasizes the simplicity of the construction of the projection of the intersection curves which derives from the geometric theory.
关键词：absolute conic; pipe diverging; ring torus; thrust bar
