Abstract: The present invention describes a valve actuator having a first motor (30) for moving a valve element and a second motor (30?) for energizing a failsafe spring (130). The second motor is operated independently from the first, thus allowing the valve element to be moved between its open and closed positions while the spring is energized. In an emergency, the spring will be de-energized and move the valve element to its failsafe position no matter the position of the valve element.

Abstract: A device for fastening together two devices (1, 30), wherein the first device (1) comprises a screw (20) with a pointed end section (26), and at least one engagement element (50) which is arranged to abut against the end section (26) and radially movable between two end positions by means of the end section (26) and in relation thereto. The second device (30) comprises a shoulder section (36) with a central opening (39), through which the engagement element (50) can be inserted when it is located in its radially inner position. The shoulder section (36) is arranged to engage with a contact section (51) of the engagement element (50) when it has been passed through the opening (39) and is located in its radially outer end position. The screw (20) is mounted rotatably, but axially immovable in relation to the frame (2), and is screwed into a nut (15), which is mounted axially movably in the frame (2) and arranged to abut against the shoulder section (36). The engagement elements (50) mounted in the nut (15).