| 摘要 |
PURPOSE:To make a ruler stand simply, accurately and vertically, by providing a level in a ruler body. CONSTITUTION:A compressing plate 5 is mounted on a mortar 8, which is placed in a mountain shape on a concrete foundation 7, and a ruler body 1 is made to stand on the plate. The ruler body is surveyed by the periscope of a transit. When the body 1 is slanted to the right or left, a bubble 3a of a level 3 is projected as a bubble 3a', which is deviated to the right or left on a front surface 4c by the reflection of light from roof surface 4a or 4b of a roof prism 4. When the body 1 is deviated to the front or rear, the bubble 3a' is projected on the position, which is deviated upward or downward, on the front surface 4c. Thus the inclination of the body 1 can be readily corrected by the periscope. Since the body 1 can be made to stand correctly and vertically, the works can be carried out accurately.
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