Translation movement guidance mechanism with positional locking, for adjustable elements of an automobile vehicle seat

The translation movement guidance mechanism with positional locking includes a stem and one or more bushes sliding in relation to the stem, the bushes being attached to a support plate which extends parallel to the stem and a locking component which includes two bearing elements more or less parallel and arranged so that, in a locking position of the locking component, they exert a gripping force on two diametrically opposite sides of the stem. The bushes are arranged so that the stem can be installed on the support plate in an assembly direction perpendicular to the support plate and the locking component includes, between the two bearing elements, a recess allowing the insertion of the stem into the recess simultaneously with the installation of the stem on the support plate. The translation movement guidance mechanism could be applied to adjustable elements of an automobile vehicle seat, especially the headrests.