crown block

基本解释

To replace the drilling line wrapped around the crown block and traveling block.
为更换缠绕在天车和游动滑车周围的钻井钢丝绳用。
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The drilling line is reeled over the crown block and traveling block to gain mechanical advantage in a "block and tackle" or "pulley" fashion.
钻井用钢丝绳通过天车和游动滑车以滑轮组的形式获得机械上效益。
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The text detailedly introduced crown block, running system, availability work period of bridge girder erection equipment and improve case for precast beams install.
详细介绍了对双导梁式架桥机天车、行走系统、有效工作长度及预制梁安装就位的改进情况。

Strongly influenced behind the scenes by the Crown family of Chicago, which owned a controlling block of shares, the company sold off most of its military businesses when the Cold War ended in the biggest fire sale the defense sector had ever seen.
FORBES: General Dynamics Begins 2013 With New Leader, Changing Business Mix