Ultrasonic systems for use in consumer, and other applications, having electromechanical motor systems providing bursts of ultrasonic mechanical vibration at an applicator repeated at a sonic frequency to produce both ultrasonic and sonic vibratory motion and effect during use of said applicator....http://www.google.es/patents/US3980906?utm_source=gb-gplus-sharePatente US3980906 - Ultrasonic motor-converter systems
