Cross-level measuring method of the plane surface which is moving and detection device null of cross-level

摘要

PURPOSE:To make quick, accurate detection of the presence, direction and extent of error in levelness by taking out detected signals from at least four detection means of continuous oscillation condition of a weight installed to be freely oscillated. CONSTITUTION:A weight 6 is suspended from a suspension rod 5 in a cylindrical body 1 to freely oscillate in every direction at the contact surface between a seat 3 and a support member 4. Detection means 8 through 11 do not produce any signal when the cylindrical body 1 is perpendicular to a measurement plane BH in level condition, or when the body 1 and the suspension rod 5 are both in vertical attitude. If the body 1 is tilted to the left in Fig. 1 for instance, a signal is produced on the light receiving side of a photo-interrupter of the detection means 10. The direction of the tilt of the measurement plane on which the body 1 is placed is known by detecting which of the detectors 8 through 11 first produced the signal.