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. The assembly comprises a blocking device which comprises a cylindrical stop housed in an extension of the second sleeve and comprising a front face against which a second end of the articulation spindle can come to bear, and a bolt-and-nut able to adopt a locked state, in which it passes through the stop and the extension so as to immobilize the stop in the extension, and an unlocked state, in which it does not pass through the stop and allows the stop to be removed from the extension.