Articulation members for back portion of vehicle seats

摘要

The articulation member comprises asymetrically guided bearing plates. A fixed flange is shaped in order to support, by means of sectors, sliding bearing plates having an upper toothing pitch corresponding to pitch of a toothing of a movable flange. The bearing plates are normally pushed back from the toothing by elastic means and have positions which are angularly shifted for two of them and submitted to bias of control means such as a cam. An angular shift of two of the bearing plates is of 120 DEG - alpha /3 (=240 DEG -2/3 alpha ) with for complement 120 DEG +2/3 alpha , alpha being an angle forming a pitch for each tooth of the toothed ring and teeth of the bearing plates.