US Patent 7128191 Actuator assembly

An actuator assembly includes an actuator, an output member, and a spring arrangement having at least one spiral return spring. The output member has a neutral position, a first actuated position, and a second actuated position. The neutral position is between the first actuated position and the second actuated position. The output member capable of being driven by the actuator from the neutral position to the first actuated position and to the second actuated position. The spring arrangement is arranged to bias the output member towards the neutral position from the first actuated position and is arranged to bias the output member towards the neutral position from the second actuated position.