Abstract: A wheel assembly provided with a bracket (1), a wheel (5) which is mounted in the bracket (1) it such a manner that it can rotate about an axle (4), a brake member (7) which can move with respect to the wheel (5) and has a brake pin (8) provided with a screw thread, around the brake pin a displaceable brake disc (9) provided with a complementary screw thread, and a locking disc (11) for fixing the position of the brake disc (9) along the screw thread. The locking disc (11) is provided with at least one pawl (12) which is positioned radially with respect to the brake pin and can be displaced substantially in the axial direction of the brake pin (8). The brake disc (9) comprises at least one radial slot (10) for accommodating the pawl (12) in order to block the displacement of the brake disc (9) along the axis of the brake pin (8).