Patent ID: 8403832

Claim:
A surgical instrument, comprising: a housing; an end effector operable from the housing to surgically manipulate tissue; an elongated shaft extending between the housing and the end effector, the elongated shaft including proximal and distal portions, wherein the proximal portion extends from the housing and defines a longitudinal axis, and wherein the distal portion is coupled to the proximal portion by at least one articulation joint such that the distal portion is movable between an aligned configuration and an articulated configuration with respect to the longitudinal axis; first and second drive cables extending at least partially through the elongated shaft and coupled to the distal portion of the elongated shaft such that reciprocal longitudinal motion between the first and second drive cables induces the distal portion of the elongated shaft to move between the aligned and articulated configurations; and an articulation drive mechanism operable to induce reciprocal longitudinal motion of the drive cables, the articulation drive mechanism comprising: an actuator including an articulation wheel movably coupled to the housing; first and second pulleys operatively coupled to opposing lateral sides of the articulation wheel to rotate about an axle in response to movement of the actuator, wherein the first pulley is coupled to the first drive cable such that the first drive cable extends on a first lateral side of the axle and wherein the second pulley is coupled to the second drive cable on a second lateral side of the axle, and wherein each of the first and second pulleys includes a circumferential groove thereon for guiding the first and second drive cables to wind and unwind from the respective pulleys as the first and second pulleys rotate about the axle; and a biasing mechanism configured to bias the first and second pulleys to at least one discrete orientation to maintain the distal portion of the elongated shaft in a discrete articulated position.