Spreading mechanism for an expandable apparatus as well as expandable apparatus

A spreading mechanism for an expandable apparatus including a stanchion and an expandable supporting structure having several pairs of support arms extending apart in a star-shaped manner and support struts hinged to the support arms, wherein the support arms are hinged to a first central fixture and the support struts are hinged to a second central fixture, and the spreading mechanism is configured to expand or close the supporting structure by reducing or increasing the distance between the first central fixture and the second central fixture, wherein the spreading mechanism includes an actuating mechanism and a pulley block with a pulley block rope, a fixedly affixed first pulley block roll holder and a movable second pulley block roll holder each with one or more pulley block rolls, through which the pulley block rope is guided, wherein the actuating mechanism is connected to the movable second pulley block roll holder of the pulley block in such a way that an actuation of the actuating mechanism causes a deflection of the movable second roll holder, and a fast end of the pulley block rope is connected to the first central fixture or to the second central fixture in such a way that it acts in a shifting manner on the central fixture to which it is connected, in order to change their distance to each other, when the actuating mechanism is actuated, wherein the pulley block is disposed in the interior of the stanchion, wherein the actuating mechanism is connected in a pull-resistant manner to the movable second pulley block roll holder of the pulley block, and wherein the actuating mechanism is connected to the movable second pulley block roll holder of the pulley block via a pull rope, a pull chain or via a rigid pull push rod.