To provide a hinge mechanism which is easier to manufacture at a lower cost while it has a preferable performance.

The hinge mechanism is provided with first and second frames (7, 8) connected together by an adjustment device (10). The adjustment device is provided with a first set of gear teeth (13) integral with the first frame (8) and a first mobile toothed component (11) engaging with the first set of gear teeth. The second frame (8) is provided with a second set of gear teeth (50), interferes with the first frame (7) when the torque applied between the first and second frames (7, 8) exceeds a predetermined threshold, in order to immobilize the frames (7, 8) rotatably in relation to each other.