derrick boom meaning in Chinese

吊货杆；吊杆；起重杆
起货吊杆
起重机吊杆

Derrick boom heel fittings - main dimensions
起重机吊杆枢轴配件.主要尺寸
Derrick boom headfittings - fixed type
起重机吊杆的顶部配件.固定型
Specification for derrick boom clamp
起重机吊杆夹规范
Ships ' light load derrick booms
船舶用轻载起重机吊杆
Shipbuilding ; fork - type heel fittings for ships ' derrick booms ; main dimensions ; identical with iso 6044 , edition 1985
造船.船吊杆根部叉头.主要尺寸