| 摘要 |
PROBLEM TO BE SOLVED: To provide a rule with which circles of various radii ranging from large to very small ones can be drawn easily, rapidly and correctly. SOLUTION: This rule is shaped like a top with a rotary pivot in a center of a rotator and a tip of the rotary pivot presses a space in a pinpointing manner by depressing an outer frame retaining the rotator from above. Thus the center position of rotation can be fixed. Consequently, the applied force becomes a rotational force due to the working of the moment of force. COPYRIGHT: (C)2006,JPO&NCIPI
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