| 摘要 |
PURPOSE:To confirm an air bubble from a top surface without bowing and to measure an angle in one direction by joining a right flank perpendicular to the 1st rule plate with a left flank perpendicular to the 2nd rule plate, and supporting the back surface end of the joined part pivotally by a hinge. CONSTITUTION:A gradient rule 12 is constituted by supporting the 1st rule plate 10a and the 2nd rule plate 10b pivotally by the hinge 11 and allowing them to be folded one over the other and spread freely. Consequently, the plate 10b is superposed on the back of the plate 10a to make the rule compact, which can be put in a pocket of a worker. If a body is at a low position or if one of front and rear observation windows 6a and 6b can not transmit light owing to the influence of an obstacle, the contamination of the window, etc., the air bubble 7a in a leveling pipe 4 is confirmed by utilizing the top observation window 6c of a top decorative plate 5c and the inclination of the body is easily measured on an angle scale 8 and a gradient scale 8b provided to the top decorative plate 5c.
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