| 摘要 |
A draw works for a mobile crane, to selectively reel in and reel out the cable of the crane by appropriate rotation of the cable pulley, includes a stable platform having mounted in fixed relationship therewith an engine with a rotatable output shaft, a rotatable speed reduction wheel, and a rotatable idler wheel. A pinion is mounted on the engine output shaft, and is aligned in a common plane with the speed reduction wheel and the idler wheel. The pinion and the reduction wheel are separated from one another, and the idler wheel is adjustably mounted on a stanchion between the two. A flexible endless belt is wrapped and retained on the pinion and the reduction wheel to engage a portion of the circumference of each for translational movement of the belt with rotation of the pinion, and thereby to rotate the reduction wheel. The belt, the pinion, and the reduction wheel are provided with transverse curved mating teeth on the respective engaging surfaces thereof for precise meshing of the belt teeth with the teeth on each of the pinion and the reduction wheel. The idler wheel is urged against the smooth outer surface of the belt to apply tension to the belt and remove the slack therefrom, and thus to increase the wrap of the belt about the reduction wheel to engage about 75% of the circumference thereof.
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