| 摘要 |
An improved laser scanning apparatus ( 46 ) for determining frame or unibody alignment or misalignment of a vehicle ( 40 ) is provided, which includes a laser assembly ( 54 ), a pair of rotatable mirror assemblies ( 56,58 ) and laser detectors ( 114,116 ) located within an enclosed housing ( 50,52 ). The laser assembly ( 54 ) has an upper pair of lasers ( 122,126 ) located in known, spaced relationship above a lower pair of lasers ( 124,128 ); detector assemblies ( 114, 116 ) are also provided including substantially parabolic reflective surfaces ( 118 a , 120 a) with detectors ( 114 a , 116 a) disposed substantially at the focal point of the surfaces ( 118 a, 120 a). The apparatus ( 46 ) is used in conjunction with a plurality of individually coded reflective targets ( 44 ) which are suspended from known reference points on the vehicle ( 40 ). In use, the laser assembly ( 54 ) in conjunction with the mirror assemblies ( 56,58 ) directs upper and lower laser beams through 360 degree scans to impinge on the targets ( 44 ); laser radiation reflected from the targets ( 44 ) is detected by the detector assemblies ( 114, 116 ), allowing trigonometric calculation of target positions using information derived from the scans of the upper and lower beams. In this way, a determination can be made if any of the targets ( 44 ) are out of plumb (i.e., not truly vertical). Preferably, the housing ( 50,52 ) includes a pair of elongated, laser-transparent panels ( 88,90 ) and is effectively sealed to minimize contamination of the apparatus ( 46 ). The provision of parabolic detection assemblies 114, 116 increases the signal-to-noise ratio for the apparatus ( 46 ).
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