US Patent 9173643 Pitch-roll-yaw surgical tool

A robotic surgical tool includes an elongate shaft having a working end and a shaft axis. The proximal end of a wrist member is pivotally mounted on the working end of the shaft to rotate around a first pitch axis to produce rotation in first pitch. An end effector is pivotally mounted on a distal portion of the wrist member to rotate around a wrist axis of the wrist member to produce rotation in distal roll. The wrist axis extends between the proximal portion and the distal portion of the wrist member. The elongate shaft is rotatable around the shaft axis to produce rotation in proximal roll.