| 摘要 |
A wheel 1 comprises a hub 2 and at least one blade element 3. An inner end 5 of each blade element is mounted to the hub, and an outer end 6 of each blade element is movable relative to the hub. The outer end of each blade element may be pivotably movable in the circumferential direction C-C relative to the hub between an expanded diameter configuration and a contracted diameter configuration, thereby the overall outer diameter of the wheel may be varied between a larger overall outer diameter D1 and a smaller overall outer diameter D2. The outer end of each blade element may move relative to the hub in response to a change in angular velocity of rotation of the hub. The wheel may comprise a second hub (11, Fig.4) movable independently of the first hub or the hub may be constructed of a first and second part (21,22, Fig.8), where they may be drawn together or separated by a holding means (26) having a cam contact profile (27). |
