A clamp for clamping a cylindrically shaped structure within a hollow cylindrical structure includes means to maintain the angular and axial position of the structures fixed while the clamp is tightened. The first core plate includes a plurality of electrically coupled conductive traces composed of a conductive ferromagnetic material layer. The key switch includes an electromechanical key insert with a key slot and is so designed that through insertion of the emergency key into the key slot and turning the elevator installation can be switched over to the emergency operation. The device further includes an element for pushing the swab towards the element to be coated so that a quantity of the composition released from the swab coats an element.