The armrest comprises a journal (12) on which the armrest turns. It is fixed to the backrest of the seat. This has a radially projecting attachment (34) supported by a turning spindle (16) for setting the angle of the armrest (10) itself. A locking device (14,26) is used to firmly attach the armrest to the journal. The locking device comprises a leaf spring (14) fitting round the journal. This spring is in the form of an open ring with two parallel angled end sectors (38,30). These end sectors can be pushed into the interior of the armrest for the assembly of the leaf spring.
