Fastening system

A fastening system comprising a rear grip part (5,41,21) to be inserted and secured within an elongated hollow body (2) of said elongated hollow body having an elongated first side containing a mounting opening (4) extending in the elongated direction of said hollow body, said rear grip part (5,41,61) insertable in a first position through said mounting opening (4) into said hollow body and displaceable therein into a second position for gripping with mounting projections (6.1, 6.2) within said hollow body (2), said mounting projections extending in the elongated direction of said hollow body, at least one stop (3) positioned exteriorly on the first side of said hollow body along opposite sides of said mounting opening, said stop (3) connected to said rear grip part (5, 41, 61) by a fastening means (9) having an axis extending through said stop into said rear grip part whereby a relative rotary movement between the stop (3) and said rear grip part (5, 41, 61) about the axis of said fastening means (9) can be effected, wherein the fastening system include a transmission system for converting a translatory movement of said fastening means relative to said stop (3) into a rotational movement of said rear grip part (5, 41, 61) relative to said stop(3).