一、问题的提出 SGD—20B型刮板输送机(简称20B)是我国最早使用的轻型刮板机之一。多年以来,平均每年有近千台左右投入使用,到目前为止,全国还有一些工厂继续生产。该产品遍及全国绝大多数中小型煤矿,其数量之多,分布之广,只有少数型号的轻型刮板输送机和它相比拟。但这种刮板输送机存在着很多缺点,如不能弯曲、中部槽易磨损、使用飘链等。尤其是该机使用的链条为模锻链,易断,常为此造成停产损失,甚至出人身事故。可是目前全国还有近万台SGD—20 First, the issue raised SGD-20B scraper conveyor (referred to as 20B) is one of the first light scraper used in China. Over the years, an average of nearly 1,000 units have been put into operation each year. So far, some factories across the country have continued to produce. The product throughout the country most of the small and medium-sized coal mines, the number of large, widely distributed, and only a handful of models of lightweight scraper conveyor and it compared. However, this scraper conveyor has many shortcomings, such as can not be bent, the central groove easy to wear, use floating chain and so on. In particular, the chain used for the machine is die forging chain, easy to break, often resulting in stop loss, or even personal accident. However, there are currently nearly ten thousand SGD-20 in the country