Seat pan of an automobile vehicle seat including an anti-submarining crossmember

Seat pan (3) of an automobile vehicle seat including an anti-submarining crossmember (6) to limit the movement of the pelvis of a user (1) towards the front of the seat, the crossmember extending crosswise to the seat pan framework (5) and being especially movable towards the rear from a rest position to an extension position and towards the front from the extension position whilst exerting pelvis retention forces during its movement towards the front of the seat, the seat pan including for this purpose extension means (10) to move the crossmember (6) from the rest position to the extension position and energy dissipation means (9) to control, from a predetermined threshold, the said retention forces transmitted by the crossmember to the occupant of the seat,

• characterised in that the crossmember (6) is installed so as to pivot around a transverse axis (A) on a sliding carriage (7) guided in translation according to a direction substantially longitudinal to the seat pan framework, the extension means (10) are arranged so as to connect the crossmember (6) and the carriage (7) to make the crossmember pivot towards the rear in relation to the carriage and energy dissipation means (9) connecting the carriage (7) to the seat pan framework (5) to exert a retention force on the carriage during movement of the carriage forwards.