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在美国,尤其在西海岸山区广泛使用索道集材。滑车是由滑轮及拉板组成的,在各固定点对运行的钢索起支撑作用。集材工必须在崎岖、陡峭的地形条件下,用人力把滑车搬运到各个固定点,因而滑车的重量被限定在50公斤左右。这一重量对普通的钢制滑车来说,只能使其滑轮直径在450mm以下。这样,滑轮直径与普通钢索直径(12～25mm)的比率即为18:1～36:1,实际上只有少数能大于20:1的比率。一些研究人员认为,滑轮与钢索的直径比例须大于200:1,才能避免钢索在负荷条件下出现疲劳。目前钢索的使用寿命是受滑轮尺寸影响的,例如一条22mm直径的钢索,把与其匹配的滑轮直径从450
Cableway skins are widely used in the United States, especially in the West Coast mountains. Pulley is composed of pulleys and pull plate, at each fixed point on the operation of the rope play a supporting role. The skidder must manually move the trolley to various fixing points under rugged, steep terrain conditions so that the weight of the trolley is limited to about 50 kg. The weight of the ordinary steel pulley, only to make its pulley diameter 450mm below. In this case, the ratio of pulley diameter to ordinary wire diameter (12-25 mm) is 18: 1 to 36: 1, in fact only a few can be larger than 20: 1 ratio. Some researchers believe that the pulley and cable diameter ratio must be greater than 200: 1, in order to avoid fatigue under load conditions in the cable. At present, the service life of the cable is affected by the size of the pulley, for example, a 22 mm diameter cable and its matching pulley diameter from 450