Seat attachment device

The invention relates to a sliding leg mechanism (A) providing longitudinal adjustment of the position of a seat, especially found in passenger transportation vehicles. The mechanism comprises an actuator body (2) with guide grooves (21), which body is rotatable on a main body (1) in order to move a locking component (6) into engagement with a rail on a vehicle floor and to move at least two rolling components (4) away from said rail by motion transmission bars (3) or vice-versa.