| 摘要 |
PROBLEM TO BE SOLVED: To provide a ruler capable of selecting various kinds of desired graduation widths with one ruler. SOLUTION: When intervals of points of intersection with slant lines 2 on a base are made equal, or set as intervals corresponding to an object like a logarithmic graduation, and a drawing is formed, points of intersection arranged by the same ratio as the intervals of the points of intersections on the base appear on all drawn parallel lines. A line having desired intervals of points of intersection is searched out of parallel lines 1 in a triangle drawn in this manner or expected parallel lines. These points of intersection are used as graduations. This sheet 4 is wound around a shaft plate 5 and rotated, thereby obtaining practical ruler.
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