A pendulous compensator for use in a light beam projector including a light beam source comprises first and second upper pulleys spaced from one another and secured to the light beam projector. First and second lower pulleys are positioned beneath the first and second upper pulleys and supported by filament...http://www.google.es/patents/US5033848?utm_source=gb-gplus-sharePatente US5033848 - Pendulous compensator for light beam projector
