The present invention is directed to a tool having a wrist mechanism that provides pitch and yaw rotation in such a way that the tool has no singularity in roll, pitch, and yaw. A positively positionable multi-disk wrist mechanism includes a plurality of disks or vertebrae stacked in series. Each vertebra...http://www.google.ca/patents/US20050090809?utm_source=gb-gplus-sharePatent US20050090809 - Surgical tool having positively positionable tendon-actuated multi-disk wrist joint
