the left edge of the door 2 is wound around the lower deflecting pulley 8 counterclockwise and runs towards the lower guide rail 4 in a substantially parallel manner towards the rear lower mounting portion 6 b starting at the rear upper mounting portion 5 b the second cable 9 b runs in a substantially parallel manner towards the upper guide rail 3 in the region of the upper edge 11 of the door 2 is wound around the upper deflecting pulley 7 counterclockwise extends in a substantially parallel manner towards the left edge of the door 2 downwardly in the vertical direction is wound around the lower deflecting pulley 8 clockwise and extends from there in a substantially parallel manner to the lower guide rail 4 towards the front lower mounting portion 6 a thus the cables 9 a 9 b are wound around the upper and lower deflecting pulleys 7 8 respectively in opposite directions so that identical deflecting pulleys can be utilized for deflecting the cables 9 a 9 b when the door 2 is displaced of course in the upper and lower region of the door 2 also respective separate deflecting pulleys may be provided for deflecting the first and.