Abstract: A safety apparatus for controlling access to a work object having an active mode and a passive mode, the apparatus having a lock assembly for obstructing access, in a first condition, and alternatively permitting access, in a second condition, to the work object; a detector for detecting when the work object is in the active mode and in the passive mode; and a control system operably interconnecting the lock assembly and the detector operable when the work object is in the active mode, as detected by the detector, to maintain the lock assembly in the first condition and when the work object is in the passive mode, as detected by the detector, to maintain the lock assembly in the second condition.