An apparatus for controlling an end-effector assembly having a first working member and a second working member is provided. The apparatus includes a first set of at least one cable, a second set of at least one cable, a first pulley configured to guide the first set of at least one cable, a second pulley configured to guide the first set of at least one cable when the second pulley is in a first position, a third pulley configured to guide the second set of at least one cable, and a rotatable element rotatable about a first axis.