| 摘要 |
A laser beam levelling instrument, which is not only intended to level but in which the laser beam is inclinable in two axes facing away from one another at right angles, has a self-levelling surveying plate at the lower end of a rotational shaft of the instrument. Disposed on the surveying plate are two spindles, facing away from one another at right angles, at the point of intersection of which there is a joint. At the ends of the two spindles remote from the joint, screw-threaded rods are disposed on the surveying plate on which rods the ends of the spindles can travel vertically. The joint has a center member which is connected to the rotational shaft by means of a pivot and an intermediate member and which is surrounded by a casing which is ball-bearing mounted on the surveying plate on vertical arms. Further disposed on the surveying plate are two spirit levels which are at right angles to one another, each level controlling an electric motor for the self-levelling of the surveying plate.
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