| 摘要 |
Rotating element catheters and catheter assemblies employ clutch assemblies for preventing rotational energy from being transmitted from a motor drive unit to the catheter element under defined circumstances. The catheter assembly includes an elongate member in which there is disposed a rotatable catheter drive cable. The catheter drive cable may have an operative element, e.g., an ultrasonic transducer or an artherctomy blade, distally mounted thereon for providing diagnostic or therapeutic functions to the physician. To control the rotation of the catheter drive shaft, the clutch assembly is configured such that the catheter drive shaft is operated in a drive mode (i.e., it is allowed to rotate) and in a release mode (i.e., it is prevented from rotating). The clutch assembly includes a driver member and a driven member, one of which is magnetic and the other of which is ferrous. The magnetic and ferrous members are arranged in relation to each other, e.g., concentrically, such that a magnetic relationship is created therebetween, which is not overcome when an applied torque does not exceed a critical magnitude, but is overcome when the applied torque exceeds the critical magnitude. |
