An end effector (400) for performing a surgical function, the end effector comprising: a coupling hub defining an opening a lock actuator (476) movable between a first actuator position and a second actuator position and being biased into the second actuator position and a lock bar (472) movable between a first bar position and a second bar position in which the lock bar extends at least partially across the opening, the lock bar being biased into the first bar position, such that when the lock actuator is in the second actuator position, the lock actuator moves the lock bar into the second bar position and when the lock actuator is in the first position the lock bar is moved into the first position.
