北京工程机械铸铁厂有三台砂型烘干炉,几年来曾采用过多种型式的卷扬机构:(1)滑轮钢丝绳天车卷扬机构;(2)卷筒钢丝绳式正反卷扬机构;(3)链条式正反转卷扬机构;(4)带棘轮滚筒紧绳机构的摩擦滑轮式 Beijing Construction Machinery Cast Iron Factory has three sand drying furnace, over the past years have used a variety of types of winch institutions: (1) pulley wire rope crane winch; (2) drum wire rope positive and negative winch; (3) chain Type positive and negative winch mechanism; (4) with a ratchet pulley tight rope friction pulley mechanism