An electro-mechanical actuator having means for transmitting motion, in the final part of a stroke performed by a system comprising a worm shaft and rider nut coupled through gearing with an electric motor, to an auxiliary interrupter for breaking the power supply to the motor. Two control levers are provided, these being coupled together, and being rotated, about a perpendicular axis, by a cursor which is fixed to the nut that slides on the worm shaft. The pivoting of the said levers is blocked during the movement of the drive shaft driven by the system consisting of the worm shaft and nut. By contrast, the levers pivot during the final part of the movement of the cursor. The distance through which the levers move in pivoting is large enough to avoid any need for the auxiliary interrupter to be a high precision component.