| 摘要 |
Two metal cables 71 pass around an upper indented wheel 11 and a lower indented wheel 2 carrying between them platforms 31 which descend in front of each floor, the upper wheel 11 also driving, by a chain 13, a flywheel 16 with a speed controlled by a centrifugal brake, while a braking system 4 with a brake pedal 41 is provided at each floor so as to permit a person to stop the rotation and to mount a platform 31, thus allowing descent to a safe lower zone solely under the effect of gravity. <IMAGE>
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