An end effector includes first and second jaws, a drive screw, a lead screw nut, and a drive beam. The drive screw is disposed within the first jaw. The lead screw nut defines a threaded bore that receives the drive screw. The lead screw nut is advanced along the drive screw as the drive screw is rotated in a first direction and is retracted along the drive screw as the drive screw rotates in a second direction. The drive beam is releasably coupled to the lead screw nut when the lead screw nut is in a retracted position. As the lead screw nut is advanced the drive beam is pulled by the lead screw nut. The drive beam is decoupled from the lead screw nut as the lead screw nut is advanced such that the lead screw nut is advanced relative to the drive beam.
