I did frame three of my four walls on the ground, then raised them with the chain hoist.
我确实在地面装好四面墙的三个框架，再用链式起重机把它们吊起来。
2
The frame of mast derrick that is designed for hydraulic wheel tractor hoist adopt welding of armor plate, its section is oblong armor plate, and its material is HG60.