天车在使用过程中是局部受力的,原天车工字钢轨设计为3吨(见图),现用四个小车分布在天车轨道上(允许超载10％),则总合力能承受13吨。将3吨电葫芦倒过来,吊耳朝下装在主横梁上。由原单滑轮改为四轮滑轮组,增加了3.5倍的提升力。行车采用电动小车。优点:新建厂房可大量减少投资,老厂房便于改造,行车改装简单。缺点:1.原电动葫芦功率恒定,起吊吨位扩大了3.5倍后,起吊速度 Crane in the course of the use of local stress, the original Crane I-beam design is 3 tons (see photo), is now used in the distribution of four trolley Crane track (allowing 10% overload), the total can withstand 13 Ton. Turn the 3-ton electric hoist upside down and load it down on the main beam. From the original single pulley to four-wheel pulley group, an increase of 3.5 times the lifting force. Driving electric car. Advantages: a new plant can greatly reduce the investment, the old plant to facilitate the transformation, traffic modification is simple. Disadvantages: 1. The original electric hoist constant power, lifting tonnage expanded 3.5 times, the lifting speed