The specification discloses a laser alignment head system for taking alignment data with respect to a pair of coupled shafts. Each alignment head includes a laser, a laser sensor for sensing a laser beam, an angle sensor for sensing the rotational orientation of the laser head, a computer...http://www.google.com/patents/US5684578?utm_source=gb-gplus-sharePatent US5684578 - Laser alignment head for use in shaft alignment
