| 摘要 |
In order to be able to define two out of the axonometric axial directions, the protractor for measuring solid angles, serving for the determination of the interrelating values of the orthogonal axonometry characteristics, i.e. angular subtenses of the ellipse and the angles of inclination of the axonometry axes, to be drawn with the ellipse drawing pattern with changing angular subtenses, is provided with two pointers of a length surpassing the diameter of the semi-circle, being fixed rotatably in the end points of said diameter, while the third axonometric axial direction is always perpendicular to the diameter of the semi-circle. Along the periphery of the semi-circle there are two angular scales increasing in opposite directions. Said scales are plotted from the centres of rotation in the endpoints of the diameter of the semi-circle as midpoints. The plate is containing a nomogram with three sets of curves for the determination of the angular subtenses of the ellipses indicating the limits of the range of interpretation. The optimum points belonging to each single area defined by the three sets of curves and defining the optimal intersecting axes are marked on the plate. On the semi-circle of the plane there is a plain protractor scale and in the centre of the semi-circle there is a longshaped groove running perpendicularly to the diameter. |
