| 摘要 |
A wheel is rotatably journalled in a supporting fork which is swivable about a substantially vertical axis. A disc is freely mounted over the wheel in a manner to straddle the fork substantially concentric with the vertical axis. The disc is provided with a brake shoe, centrally of its lower surface, in opposition to the surface of the wheel and the disc is movable, by a lever, operated by a pedal or manual assembly, into contact with the wheel. |
