| 摘要 |
<p>The wheel chair has a simple frame supported by two large rear wheels and two smaller castor type front wheels. The brake operates on the wheel axle via a drum (5) on the hub of one rear wheel. The brake is operated by pulling on the end of a lever (6). Inside the drum are two semicircular brake shoes which are linked at one end and held apart at the other by a mechanism acted on by the lever. The drum is protected by a cap (16). The cap, drum and shoe operating mechanism are held in place on the end of the axle by a knurled nut, which can be easily removed for maintenance purposes.</p> |
