大型起重机和挖掘机是一种体积大、重量可达数十吨乃至百吨的活动作业设备。经常要从一个工地转移到另一个工地,这种设备的转移往往受到道路的限制。在国外,解决这个问题的办法是将超重机或挖掘机解体为两部分来运输。回转式起重机或挖掘机都分为相对独立的上下两个部分,回转机构和底盘机构。两机构中间只有一套大型回转轴承联系着,将机器分开的办法就是把这个轴承拆开,到达新工地后再将其装上。轴承的内圈或外圈都是靠螺栓固定在机器上的。在一个大型轴承圈上,可有70个粗直径的螺栓。如要逐个拧下或紧固如此数目的大螺栓,是 Large cranes and excavators is a large, weight up to tens of tons and even one hundred tons of active operating equipment. Often from one site to another site, the transfer of such equipment is often limited by the road. Abroad, the solution to this problem is to disassemble the overweight machine or excavator into two parts for transport. Rotary cranes or excavators are divided into relatively independent upper and lower parts, slewing mechanism and chassis mechanism. There is only one large slewing bearing in the middle of the two mechanisms, and the way to separate the machines is to disassemble the bearings and attach them to the new site. Bearing inner ring or outer ring are bolted to the machine. In a large bearing ring, there are 70 rough diameter bolts. To unscrew or fasten so many large bolts one by one, yes