| 摘要 |
<p>The invention relates to a device for adjusting the angle of a sighting unit (1) towards a target, in particular for a geodesic-measuring instrument. The inventive device comprises a reference base (2), at least one bearing (3) for mounting the sighting unit (1) thereon in such a way that it is pivotable with respect to said reference base (2) around an axis (4), a gear for accurately adjusting an angle of rotation around said axis (4) between the sighting unit (1) and the reference base (2) and a coupling unit for limiting or interrupting a torque flux around the axis (4). The gear and the coupling unit are in series arranged in the torque flux between the sighting unit (1) and the reference base (2). The torque flux is carried out around the axis (4) between the sighting unit (1) and the reference base by means of the gear and the coupling unit when it is non-interrupted thereby. Said device is characterised in that the coupling unit is provided with at least one electromagnet (5) for producing a magnetic field and the torque flux can be limited or interrupted according to the interruptibility of the magnetic field.</p> |
