An end effector of a surgical tool may include a housing, a jaw support shaft, jaw members, an articulation member, and cam pulleys. The jaw members may be supported on the support shaft and may be pivotable about a pivot axis. The articulation member may have a slot and include articulation pins extending from it that are coupled to the jaw members. The slot may be adapted to receive the jaw support shaft to support the articulation member between the jaw members. The articulation member may be rotatable about the jaw support shaft to articulate the jaw members relative to the longitudinal axis. The cam pulleys may be mounted to the housing and coupled to the jaw members. The cam pulleys may be rotatable about the pivot axis to pivot the pair of jaw members between open and closed conditions.