Transport device and wheel unit control

A wheel unit (101) comprising one or several wheels (102, 103) being arranged for rotation about at least one wheel axle (104) during movement of the wheel unit along a support surface (105), wherein the wheel axle can be brought into different turning positions about a turning axis (106) extending substantially perpendicularly to the wheel axle, and wherein the wheel unit further comprises at least one turning means for controlling the turning position. The wheel axle (104) is adapted for axial displacement (Y) relative to the turning axis (106) in dependence upon external forces (F) acting on the wheel/wheels (102, 103) and/or on the turning axis (106), by means of the wheel axle being interconnected with the turning axis via a sliding device, wherein the turning means (108) is adapted for returning the axial displacement toward a normal position during the movement along the support surface by means of said control of the turning position.