Abstract: A closure operating device comprises a control unit for controlling a power actuator operatively connected to a closure to selectively open and close the same. The control unit and the power actuator are mounted to a casing adapted to be mounted on a wall. The casing defines an interior space which is normally closed by a lid which defines itself a compartment for receiving parts of the control unit. A limit switch mechanism is mounted in the compartment for automatically interrupting power transmission to the power actuator when the closure reaches a fully open position or a fully closed position thereof. The limit switch mechanism includes a pair of switch actuators threadably engaged on a shaft. The switch actuators are normally locked against rotation by an anti-rotation member. The anti-rotation member is adapted to be independently disengaged from the switch actuators to prevent accidental displacement of one of the switch actuators while the other one is being manually adjusted.