图１所示是我厂机床设备上一个破碎了的皮带轮。由于皮带轮只剩下残缺的一部分 ,不是一个完整的能直接测出直径圆 ;而且皮带轮无图纸 ,给重新制造该皮带轮带来了困难。为此 ,我们采用了用普通卡尺来测量皮带轮剩余圆弧部分弦长和弦高的办法 ,对皮带轮进行了测绘 ,使问题得到了 Figure 1 shows a broken pulley on our machine tool equipment. Because the pulley has only a few missing parts, it is not a complete circle that can be measured directly; there is no drawing on the pulley, making it difficult to remanufacture the pulley. To this end, we use the ordinary calipers to measure the chord length of the remaining part of the arc chord way, the pulley was mapping, the problem was