DE 20 2006 008 867 U1 discloses an apparatus for fastening a solar installation on a roof. The apparatus comprises a hanger bolt, to the threaded shaft of which a flat metal connecting plate is screwed firmly by means of two nuts. The metal connecting plate has an elongated hole, on which a mounting rail can be fastened in an adjustable manner. A second screw is necessary for fastening the mounting rail.
DE 20 2007 008 471 U1 discloses an apparatus which can fix a profile rail to another component by means of a wedge, which is guided on a ramp, and just one screw. The apparatus is designed for a planar mounting base which is larger than the two-part rear surface of the apparatus. The distance between the screw and the profile rail is also fixedly predetermined.