Abstract: The apparatus comprises a leverage including at least two parallel arms pivotally mounted at their central portions, having one pair of the ends threof spread by the end piece of a driving rod and actuated, for instance, by a solenoid. The opposite pair of ends of the arms is operatively connected with a driven rod by means of wedge type engagement. Rollers are interposed between the contact surfaces of the arms and the respective rods. The mechanism cuts down the amount of energy required for transmitting a command, offers fast action and reliability.

Abstract: An arrangement for retaining an actuating member in an extreme position which has a connecting element held in permanent engagement with the actuating member and received between a pair of supports to which the connecting element is pressed by at least one coil of wire wound about the supports with an effort sufficient for retaining the actuating member in its extreme position. The wire is selectively connectable to a source of power so that the wire is heated up whereby the pressure of the supports against the connecting element is reduced, and the connecting element is released to move relative to the supports, thus releasing the actuating member, so that the latter moves through its working stroke.