Abstract: The invention relates to a fastening device (14) for establishing a self-adjusting fastening connection between at least two elements. The fastening device comprises a frame (15) having at least one opening and a connection (27) to one of said at least two elements. Further, it comprises a rod (18) with corrugations, said rod being movable through said at least one opening and it includes a connection to one of said at least two elements and a holding device (20) comprising at least two locking elements (20a, 20b), each locking element including at least one surface comprising dents/grooves partly or totally corresponding to said corrugations. Even further, at least said frame (15) or said holding device (20) comprises an at least partly tapered shape, and elastic means such as spring means (21) forcing said holding device (20) against said frame (15) and thereby said locking elements (20a, 20b) against each other.