Patent ID: 7614115

Claim:
A wheel structure with a central control, comprising a central controlling shaft, the central controlling shaft having at a first end thereof a connecting part for controlling the central controlling shaft; the central controlling shaft having a controlling piece at a second end thereof; the controlling piece having two protrusions sticking outwards from two edge portions thereof; a bearing on the central controlling shaft; a central sleeve joined to the central controlling shaft; the central sleeve having a plurality of grooves on an inner side thereof; the central sleeve having two opposing rails on an inner side thereof; the central sleeve having two opposing slots, which are formed on the rails respectively; the central sleeve having two extension portions; a wheel member pivoting on the extension portions of the central sleeve; a position-limiting element secured inside the central sleeve, next to the controlling piece of the central controlling shaft; the position-limiting element having a middle position-limiting hole having a same outline as the controlling piece; the position-limiting element having a plurality of detainment protrusions, which are received in the grooves of the central sleeve; a braking unit received in the central sleeve, the braking unit includes two sliding block portions, which rest on the rails of the inner side of the central sleeve respectively; the braking unit having a passage extending through both the sliding block portions thereof; the braking unit including a braking piece on a bottom thereof to face the wheel member; a pressing plate passing through the opposing slots of the central sleeve as well as the passage of the braking unit; the pressing plate being biased upwards by means of elastic elements positioned in the slots of the central sleeve; and a shell covering the central shaft and the wheel.