Device for connecting and interlocking of two base plates, especially floor panels

A device for connecting and locking two building boards on their longitudinal sides and/or transverse sides in a horizontal and vertical direction through an essentially vertical joining movement, the building boards have a top side and an underside, on their lateral edges (I, II) to be connected to one another are provided with profiles corresponding to one another, and a locking element with a locking projection provided in the profile of the first building board, the locking projection interacts with a locking depression provided in the profile of the second building board such that the two building boards are automatically locked in the vertical direction with the joining movement, the locking element being embodied in an essentially rigid manner and the locking projection being brought into the locking depression through a rotary motion of the locking element, wherein the locking element is embodied in cross section in a substantially circularly c-shaped manner.