An instrument adapter includes a housing, a drive member, a nut, and a shaft assembly. The nut is threadedly coupled to the drive member and axially movable relative thereto. The shaft assembly includes a shaft and a link. The shaft extends distally from the housing and is configured to be operably coupled to an end effector. The link has a proximal end movably coupled to the nut and a distal end configured to selectively lock the end effector to the shaft assembly. The link is movable between a proximal non-locking position, and a distal locking position. The nut is movable between a first position along the drive member, in which the nut resists proximal movement of the link from the distal position to the proximal position, and a second position, in which the nut does not resist proximal movement of the link from the distal position to the proximal position.
