LOCKING MECHANISM

A locking mechanism for locking to grooves of a circular bore or member, comprises a main body (118") with a plurality of locking members (119") arranged along a perimeter of the main body. The locking members are rotatably supported on the main body about is rotation axes (117t"). An actuation ring (117a") comprises a plurality of engagement elements (117d") which extend into engagement slots (117e") of the locking members, so as to rotate the locking members. The locking members according to their rotational position can assume a locking position, wherein their perimeter extends a first distance radially out from the locking mechanism or radially inwardly from the locking mechanism, and an unlocked position, wherein said distance is shorter than the first distance or non- existent, as the distance from the axes (117r) of the locking members to their perimeter varies along the perimeter.