Abstract: The invention relates to a device for a bi-directional displacement of a means or a connecting element, along a guide, which can be reversibly moved between at least two positions along the guide, with a means for driving that can be engaged with the means or connecting element, which is capable along the guide to displace the means or connecting element in a direction while being subjected to force and an actuator engaged with the means or connecting element, which is capable of displacing the means or connecting element in the opposite direction along the guide while being subjected to the force and wherein the actuator is actuatable by a converter material.