Abstract: An actuator employing a unidirectional electric motor driving a first rotating member connected to a second rotating member through a pivotable link of which a first end is connected to the first rotating member at a smaller distance from its axis of rotation than the distance between the point at which the second end is connected to the second rotating member and its axis of rotation. An enegerization circuit includes first and second limit switches through which the motor is alternately energized to rotate the second men%her in opposite directions to first and second limiting positions respectively.

Abstract: A mechanical rotary coupler for first and second coral shafts having slotted ends proximate one another, the coupler being formed of an elongated blade of resilient material longitudinally slit and folded on itself transverse to the slit to provide first and second resilient V-shaped strips connected by bridging portions at the ends of the blade, the strips respectively being adapted to engage the slots in the ends of the first and second shafts at regions on the strips spaced from the bridging portions.