The seat has a cushion (4) attached to a frame (10). Its rear (11) is suspended by at least one rear bar from a second frame (20) that holds the backrest. Its upper end is attached to the second frame by a pivot (31), and its lower end to the first frame by a second pivot (32). The lower end can be moved forwards and backwards in relation to the second frame. The first frame's front part (12) is attached to the second frame by a special mechanism (40). This coordinates with the bar to allow the first frame to move backwards and forwards. Also, the weight of the user does not push it all the way back.
