| 摘要 |
There is provided a platform elevator comprising i) an upright frame having first and second elongated upright members provided with a longitudinal track and an elongated generally orthogonal leg at their lower end, and connected to each other at an upper end thereof by an elongated hoisting box having at least one windable flexible slender hoisting member having a portion extending from a lower end of the box and cooperating with at least one pulley and the frame to constitute a hoisting tackle, and ii) a cantilever platform connected to the tackle and comprising a generally horizontal supporting surface and first and second lateral upright runners adapted to glide in respective tracks of the upright members. Thereby, winding or unwinding the hoisting member causes the platform to be upwardly or downwardly translated by the tackle while being guided by the runners traveling in the tracks. According to a further aspect of the platform elevator, the hoisting box may further comprise a hoisting member winding means driven by a rotatable shaft connected to a compensating coil spring for partly counterbalancing platform weight and load.
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