Abstract: A swivelling wheel assembly containing a wheel whose swivelling action around a vertical axle may be locked or unlocked by rotating the wheel in one direction or the other. A curved double control lever is housed in a space between the thrust bearing and the tread of the wheel in the area of the lateral extensions of the fork joint. A lower lever arm holds a friction device engaging the tread of the wheel. An upper lever arm contains a locking means which can be received in a locking slot constructed in a housing component which is fixed relative to the pivot axle. A circular cover of the fork joint contains a tracking groove to guide the upper lever arm.