Method for the detection of the centre of a laser beam projected by a levelling device (so-called construction laser) by means of at least two laser-sensitive signal-transmitting receiving elements arranged in a mirror image about a zero line, and device for carrying out the method

摘要

The invention relates to a self-calibrating receiving device for the accurate detection of the centre of a laser beam projected by a levelling laser device (so-called construction laser), this laser beam generating a control signal when it impinges on any one of the photodiodes (5a, 5b) above or below the "zero line" (19). On the basis of these signals, the slide (4), on which the photodiodes (5a, 5b) are arranged in a mirror image about the fixed "zero line" (19), is displaced automatically by a servo motor in one direction or the other until the centre of the projected laser beam impinges exactly on the "zero line" (19) (= lined-up condition). This lined-up position is indicated optically by means of a light-emitting diode (17) and/or acoustically by means of a buzzer (20). A marking-out scale (9) is arranged at right angles to the displacement direction of the slide (4) in such a way that its upper edge (21) lies exactly at the level of the "zero line" (19) and serves as a marking-out edge so that, after reaching the lined-up condition, the zero level transferred by the projected laser beam can be marked out on the wall. <IMAGE>