An assembly having an articulation spindle mounted in a first sleeve inserted into a first arm of a clevis and in a second sleeve inserted into a second arm of said clevis, and a blocking device. The blocking device comprises a nut screwed onto an extension of the second sleeve and comprising an inner shoulder acting as a stop for a second end of the articulation spindle, at least two locking washers engaging with the nut, a tab washer comprising an element immobilizing it in rotation with respect to the second arm of the clevis, and for each locking washer, a blocking element limiting the rotational movement of the locking washer with respect to the tab washer.