A contact free rotary transformer assembly can be used to transfer power and information between a stationary portion and a rotatable portion of a laser scanning device. The rotary transformer can consist of a pair of substantially parallel ferrite rings, each having disposed therein a coil for passing...http://www.google.fr/patents/US7187823?utm_source=gb-gplus-shareBrevet US7187823 - Contact-free slip ring for survey instrumentation
