NOVELTY - The apparatus (3) has a base member fixed to a chassis, and a seat supporting member arranged to supportably receive a seat and moved in relation to the base member. A linear drive unit is connected to the base member and to the supporting member for moving the supporting member along a motion path in relation to the base member. The supporting member has a cam surface arranged to be in supporting contact with a rotational support member of the base member for altering an angle between the supporting member and the base member during movement along an interval of the motion path.    USE - Seat tilt apparatus for an electric wheelchair (claimed).    ADVANTAGE - The cam surface of the seat supporting member is arranged to be in supporting contact with the rotational support member of the base member for altering the angle between the supporting member and the base member during movement along the interval of the motion path, thus achieving reliable, smooth and comfortable tilting of the seat at a comparatively high speed and with an efficient usage of the electrical power supplied to the electric motor. The apparatus utilizes reduced number of moving parts, thus enhancing reliability and service life of the apparatus, and reducing the need for maintenance of the apparatus while allowing for space saving of the apparatus. The apparatus utilizes a resilient member so as to ensure that play is not defined between the rotating support members and the cam surfaces such that the angle of equilibrium is passed without any disturbance or uncomfortable jerk or disruption. The longitudinal direction of guide slots of the seat supporting member are arranged forwardly sloping, with an angle of inclination of approximately 5.5 degree to a horizontal plane, thus achieving comparatively large maximum tilt angle with a comparatively short active length of a threaded rod while keeping the active lengths of the cam surfaces comparatively short. The curvature of the cam surface along a longitudinal portion, which corresponds to the subsequent tilting is arranged with a gradually increased gear ratio, such that speed of the tilting movement is increased as the gravitational counter-action is decreased, while maintaining the power required for accomplishing tilting at constant rate.    DESCRIPTION OF DRAWING(S) - The drawing shows a front perspective view of a wheelchair provided with a seat tilt apparatus.    Chassis (1)    Seat (2)    Seat tilt apparatus (3)    Front wheels (4)    Rear wheels (5)    Seat frame (6)    Seat bottom (7)    Backrest (8)    Arm rests (9)    Leg rest (10)