US Patent 6866635 Transducer position locking system

An ultrasonic endoscopic probe tip device which provides signals to an imaging system for transesophageal diagnosis includes a removable housing adapted to be attached to the distal end of an endoscope. A rotatable, ball-bearing-mounted phased array transducer within the housing is rotatable around its acoustic propagation axis through multiple turns. The transducer is driven by an immersed micro-motorized drive. A torque limiting gearbox couples the drive to the transducer. A position encoder provides the imaging system with transducer position information over a 360° range. An automatic transducer position locking/unlocking system is used to lock the transducer in a selected rotational position.