An ultrasonic transducer is disclosed comprising a transducer head assembly containing a movable crystal holder containing a crystal which is coupled to a stationary base by mechanical linkage means. A motor adapted to provide linear reciprocating motion is coupled to the mechanical linkage means for...http://www.google.fr/patents/US4421118?utm_source=gb-gplus-shareBrevet US4421118 - Ultrasonic transducer
