The cover (3) is preloaded to swivel in the opening direction on an edge (2.1). The edge bounds the tub-shaped container (2) and acts as a hinge. A preloaded device on one side of the edge lying opposite the form engagement means is pivoted in such a way that the cover automatically opens if the form engagement means is released. To produce the preloading of the cover in the opening direction the hinge edge has a form memory and/or elastic capability.
