Abstract: A gripper for a surgical attachment has first and second pivotable opposed arms. A spring pretensions the arms in an opening direction. The first arm has a spur and a through-hole. A pin on the second arm has a cap which passes through the through-hole and protrudes from the first arm when the gripper is closed. A link plate is fastened moveably on the first arm, above the through-hole. The plate has a thumb-actuatable projection and a recess to interlock with the pin cap against the force of the spring in the closed position.