| 摘要 |
PROBLEM TO BE SOLVED: To provide a rule which is inexpensive, lightweight, and conveniently carried and to make it possible to draw standard lines dividing equally the heights of the stack of all sheets with only one rule. SOLUTION: On an XY system which has its origin at an arbitrary straight line AB as one side a reed screen while the tallest height and lowest height of the stack are denoted as H and L and the largest and smallest numbers of divisions are denoted as (m) and (n), straight lines y=k,..., y=nk are drawn on the reed screen radially from the origin O so that at least both straight lines y=mk and y=nk among the straight lines y=k,..., y=nk cross both straight lines y=H and y=L on the reed screen. The reed screen is made to abut against flanks of the stack of the sheet and division lines are drawn on the flanks of the stack of the sheet according to the straight lines y=k,..., y=nk drawn on bent parts of the reed screen. Consequently, necessary equal division lines can all be drawn with only one rule.
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