Patent EP-2453204-A1 (EP)
Inventor: KEHL ANTON
IPC: G01C15/00
Filed: 2010-11-10
Abstract: The construction laser system comprises a laser unit, a rotatable deflection unit having a rotary laser (1) for emitting a rotating laser beam, which defines a reference surface, a laser receiver (5) to determine a position relative to the reference surface, a laser beam detector to generate an output signal upon impact of the laser beam on the detector, an evaluation unit for determining the position of the laser receiver relative to the reference surface, and an indicator for indicating whether the laser receiver exactly coincides with the reference surface. The construction laser system comprises a laser unit, a rotatable deflection unit having a rotary laser (1) for emitting a rotating laser beam, which defines a reference surface, a laser receiver (5) to determine a position relative to the reference surface, a laser beam detector to generate an output signal upon impact of the laser beam on the detector, an evaluation unit for determining the position of the laser receiver relative to the reference surface, an indicator for indicating whether the laser receiver exactly coincides with the reference surface, and a control system designed for the laser unit. A known emission pattern is produced over a sequence of revolutions by a variation of the emission of the laser beam temporally coupled with a rotation period of the deflecting unit. The evaluation unit is designed to: identify the reference surface based on a sequence corresponding with the known emission patterns by the laser beam detector, where the rotating laser beam generates output signals; and compare the sequence of generated output signals with the known emission patterns marked by comparison criteria, which is stored in the evaluation unit. The control system is configured such that the laser beam is emitted as the emission patterns at each n-th revolution for the rotation period with a light output lying outside of a defined standard light output area, where n is 3-10. The evaluation unit is designed to identify the reference surface such that the sequence of output signals of each n-th output signal exhibits amplitude differing from the amplitudes of other output signals or does not exhibit the amplitude. The control system is configured such that the laser beam is emitted with constant light output than standard light output in other revolutions. The revolution rate of the deflection unit is adjustable at different values within a rotational rate range of 7-20 revolutions per second. The evaluation unit is designed for further identification of the reference surface based on the time distances of the individual output signals within the sequence of generated output signals. A teach-in sequence corresponding with the emission pattern of the laser beam detector is detected and analyzed during the generation of the output signals by the rotating laser beam. The comparison criteria are derivable from the teach-in sequence such that the criteria is characterized by the emission pattern, and the generated output signals are adapted for comparison with a sequence of part of a further measuring operation. The information with periodically recurring differences in the amplitudes of the individual output signals is derived and stored as the comparison criteria within the teach-in sequence. The indicator is designed such that the determined position of the laser receiver relative to the reference surface is displayed only in the case of identification of the reference surface and/or the indicator is configured to indicate whether the reference surface is identified. The information is: determined, by the evaluation unit, as the position of the laser receiver relative to the reference surface; and located exactly on the reference surface, above the reference surface or below the reference surface, where the information is displayed by the indicator as the determined position. The laser beam detector comprises photosensitive elements, and/or the evaluation unit and the indicator are located in the laser receiver. The control system is integrated into the rotating laser. Independent claims are included for: (1) a rotary laser; (2) a laser receiver; and (3) a method for determining a position from a laser receiver relative to a reference surface defined by a rotating laser beam.