The invention relates to a wheelchair device for actively moving a seat unit (12), particularly a seat part (14) and/or a backrest part (16) of the seat unit (12), of a wheelchair (18), with at least one movement conversion unit (24) that can be arranged at least partially on at least one drive wheel (20, 22) of the wheelchair (18) and is used to convert a movement of the at least one drive wheel (20, 22) into a movement of the seat unit (12). According to the invention, the movement conversion unit (24) is embodied as a cam mechanism unit, the movement conversion unit (24) comprising at least one movably mounted cam mechanism element (26) that can be arranged on the seat part (14), at least for acting on the seat part (14), said cam mechanism element comprising at least one contact surface (28) that interacts with at least one movement guideway (30) of at least one other cam mechanism element (32) of the movement conversion unit (24).
