| 摘要 |
PURPOSE:To enable the deflection and the deflection angle of an apparatus to be measured relative to parallel rays to be rapidly and efficiently measured even in a curved tunnel or the like by fixedly mounting a surveying instrument to the apparatus, such as a shield tunneling machine, and receiving the plane-wise irradiated parallel rays. CONSTITUTION:A surveying instrument is composed of a shielding plate 2 provided substantially perpendicularly to plane parallel rays and having an inclined slit 2a, a convex lens 3 provided behind the shielding plate 2, a screen 6 provided perpendicularly to the optical axis of the lens 3 between the lens 3 and its focus, a cylindrical lens 7 provided between the screen 6 and the lens 3 so that the optical axes of the lenses 3 and 7 coincide with each other and the resultant focus of both the lenses 3 and 7 is formed on the screen 6 and detecting means 8 for detecting the position of a light spot P at which the rays are focused on the screen 6. The instrument thus constituted is fixedly mounted to an apparatus to be surveyed and receives the plane parallel rays. The rays are transmitted through the shielding plate 2 and the lenses 3 and 7 and images as the light spot P and, from the (x) and (y) coordinates of the light spot P, the deflection and the deflection angle of the surveying instrument can be obtained. |
