使用苏制Э-125、波兰制KN-1001、国产W-1001等起重机时,常发生起重臂突然下落(亦称为掉杆)的严重事故。轻者砸坏构件,重者造成人身伤亡、损坏建筑物。但是,不少吊车司机和管理干部,不了解或不甚了解掉杆的原因,因而没有积极的预防。致使掉杆事故往往多次重复发生。如冶金部第 When cranes such as Soviet-made Э-125, Polish-made KN-1001, and domestic-made W-1001 are used, serious accidents such as the sudden drop of the boom (also referred to as the drop of the lever) often occur. The light elements are damaged and the heavy ones cause personal injury and damage to buildings. However, many crane drivers and management cadres do not understand or do not understand the reasons for the loss of the rods, and therefore do not have active prevention. As a result, accidents with falling rods often occur repeatedly. If the Ministry of Metallurgy