Abstract: The invention features a hinge or coupling two panels (P1, P2), one of which at least opens rotatably about an axis (X) parallel to the planes of the said panels, comprising a mobile fixing element (1) on the opening panel, a fixing element on the other panel and linking means (3) between the fixing elements co-operating with elastic return means of the panel opening to at least a stable angular equilibrium position, characterized in that the said return means consists of a ring (4) located in a cavity (10) of the mobile fixing element (1) and capable of being elastically deformed by the pressing action of a cam (30) rotating about a central shaft (5) parallel to the planes of the panels, being carried by the linking means (3).