| 摘要 |
1. Levelling means on a drainage machine or the like, with which trenching tools (4), together with a laser receiver (8) arranged on a laser mast (11), are positioned on a platform (10) and are automatically re-adjusted, only in height, relatively to a driving unit (5) of the drainage machine, along a laser guiding beam of a laser transmitter at a fixed position in the ground, by means of a power drive controlled by the laser receiver (8), characterized in that the laser mast (11) on the platform (10) is mounted to be swivellable about a shaft extending longitudinally of the drainage machine and is held in the vertical position by an automatic position control means (13, 20, 21), and with which, corresponding to the angle of slope between the platform (10) and the laser mast (11), the height position of the laser receiver (8) is automatically corrected relatively to the platform (10), that the laser mast (11) is arranged on transversaly extending rocking lever (15), pivotable at will about one of two pivot shafts (16, 17) relatively to the platform (10), that the two pivot shafts (16, 17), for deriving a height correction value, are arranged symmetrically with lateral spacing to both sides of the mean axis (9) of the drainage machine in the longitudinal direction thereof, and that, depending on the direction of the inclined position of the drainage machine, that pivot shaft (16, 17) which is higher at the time in an unbalanced inclined position is selected. |
