derrick mast

基本解釋

Do not throw objects off the floor, mast or derrick.
不允許從鉆臺上或井架上，往下亂扔?xùn)|西。
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Tools carried into the derrick or mast should be secured to the body.
帶到井架上的工具應(yīng)當(dāng)綁在身上。
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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.
為滿足液壓輪式通井機(jī)的使用要求而設(shè)計(jì)的桅桿式井架采用板焊結(jié)構(gòu)，主體截面為長方形的方形鋼，材料為HG60。