Abstract: A locking mechanism is provided which is characterized by one or more blocking elements each consisting of two complementary semi-cylindrical parts (2),(3) snugly located in a correspondingly shaped aperture (4) defined between two relatively movable parts (5),(6) to be locked together, one of the semi-cylindrical parts (2),(3) being adapted to be operatively coupled to a key (8) to permit rotation of the two complementary semi-cylindrical parts (2),(3), whereby the two semi-cylindrical parts (2),(3) can be rotated between a position in which they prevent movement of the two lock parts (5),(6) and a position in which the two lock parts (5),(6) are relatively movable.