A drive and improved ground spindle assembly for a disc recorder and particularly one using a rigid disc having a direct coupled spindle shaft arrangement which includes a disc support platform mounted concentrically at one end of the spindle shaft and a DC motor attached to the other end of the spindle...http://www.google.fr/patents/US4216512?utm_source=gb-gplus-shareBrevet US4216512 - Disc recorder with brushless DC motor drive
