qizhonghuacheshiyizhongjianyidexiaoxingdiaozhuanggongju，tajiegoujiandanshiyongfangbian，genjushiyongfangfadebutongkeyifenweidinghuachehedonghuache，dangeqizhonghuachezuoweidaoxianghuacheshiyong
，dangezhinenggaibianlidefangxiang，bingbunengshengli,如用兩隻或多隻配合並用鋼絲繩把它們圍繞在一起組成滑輪組，不僅能改變力的方向，而且能省力。