Abstract: A seat unit includes a frame structure and a seat. A linkage assembly interconnects the frame structure and the seat for displacement of the seat relative to the frame structure between a lowered sitting position and a raised position to provide assistance for the person using the seat unit to stand up therefrom. The linkage assembly causes the rearward part of the seat to be raised by a greater distance than the front part so that the seat also tilts forwardly. First and second springs urge the seat towards its raised position, the springs being operable in combination to produce an overall spring force urging the seat towards its raised position with a spring force value which is of a desired magnitude in each part of the movement towards the raised position.