The invention concerns a cover (10) intended for closing an opening of a vessel defined by an opening rim, the cover comprising: -a first cover portion (11), -a second cover portion (12) mounted so as to be able to pivot on the first cover portion about a pivot axis (14) with an axial direction, between a first angular position releasing the cover and a second angular position locking the cover in which the cover is intended to be axially locked on the opening rim of the vessel extending around the pivot axis, -a plurality of locking members (13) distributed around the pivot axis, each of the locking members being mounted so as to be able to move relative to the first and second cover portions between a releasing position and a locking position in which the locking member is radially closer to the pivot axis than in the releasing position and in which it is intended to cooperate with a radially outer surface of the opening rim of the vessel in order to axially lock the cover relative to the vessel, the cover being further designed such that each of the locking members is moved from its releasing position to its locking position, when the second cover portion pivots from the first angular releasing position to the second angular locking position.L'invention concerne un couvercle (10) destiné à obturer une ouverture d'une cuve définie par un rebord d'ouverture, le couvercle comprenant: -une première partie de couvercle (11), -une deuxième partie de couvercle (12) montée pivotante sur la première partie de couvercle autour d'un axe de pivotement (14) de direction axiale, entre une première position angulaire de déblocage du couvercle et une deuxième position angulaire de blocage du couvercle dans laquelle le couvercle est destiné à être bloqué axialement sur le rebord d'ouverture de la cuve s'étendant autour de l'axe de pivotement, -une pluralité d'organes de blocage (13) répartis autour de l'axe de pivotement, chacun des organes de blocage est monté mobile par rapport
