System for adjusting the longitudinal position and maintaining therein a motor vehicle seat

An adjustment system for a seat including at least one foot adapted to be mounted to the seat, and a slideway having a longitudinal slot configured to receive the foot in a sliding manner. The foot has an expandable mechanism with locking members having symmetric and opposed action relative to a central longitudinal plane. The slideway has a plurality of locking portions. The expandable mechanism has a first position in which the locking members are oriented with a first transverse width such that the expandable mechanism can be introduced into and extracted from the slot. The mechanism has a second position where the locking members have a second transverse width such that a locking member is engaged to a locking portion, thereby immobilizing the foot relative to the slideway. And, the expandable mechanism has an intermediate position where the locking members have a third transverse width such that the locking members are disengaged from the locking portions to permit longitudinal displacement of the foot relative to the slideway, and such that the locking members are retained within the slot.