| 摘要 |
The chassis (3) on the barrow has small support wheels or slide feet, and acts against the ground in a line near to that through the support points of the wheels (2). It moves downwards in relation to the barrow which is then made to lift. - The main wheels then roll up the vertical part of the stair step, over the edge, and inwards on to the top of the step. The chassis is then drawn upwards, and the work cycle is repeated. When coming downstairs, the work cycle is reversed. |
