An apparatus includes an end effector, a shaft assembly including a translating drive member, and a drive assembly. The end effector includes a distally advancing cutting member and staple driver. The translating drive member (326) is operable to actuate the end effector. The drive assembly (300) is configured to induce linear motion on the translating drive member and includes a motor (306) fixed to a frame (70), a rotary drive member (308), a first link (310), and two toggle links (316, 318). The rotary drive member is rotated by the motor. The first link is driven by the rotary drive member. One of the two toggle links is pivotally connected to the translating drive member and the other one is pivotally connected to the frame (70). The rotary drive member is operable to convey linear motion to the first link. The first link further conveys linear motion to the translating drive member by means of said two toggle links.
