crownblock meaning in English

天车

Control of the technological indexes in the steel crownblock beam manufacture
天车钢梁制做工艺指标控制
The rigs indlude special carrier ( developed by our company ) , engine , hydraulic transmission , right angle gearbox , single ( double ) drum drawwork , rotary table transmission box , hydraulic drawworks , front and rear supporting frame , double - section hydraulic telescopic mast , crownblock , travelling hool , weight indicator , hydraulic , pneumatic and electrical system , etc
专用底盘为载车，由专用汽车底盘、发动机、液力变速箱、角传动箱、单（双）滚筒绞车、转盘传动箱、液压绞车、前支架、后支架、双节液压伸缩式井架、天车、游车大钩、指重表、液压系统、气路系统、电器系统等组成。