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A derrick is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a boom hinged at its base to provide articulation, as in a ''stiffleg'' derrick. The most basic type of derrick is controlled by three or four lines connected to the top of the mast, which allow it both to move laterally and cant up and down. To lift a load, a separate line runs up and over the mast with a hook on its free end, as with a crane.〔(【引用サイトリンク】url=https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=9832&p_table=STANDARDS )〕 Forms of derricks are commonly found aboard ships and at docking facilities. Some large derricks are mounted on dedicated vessels, and known as floating derricks〔(【引用サイトリンク】url=https://www.dir.ca.gov/title8/4885.plates.html )〕 and sheerlegs. The term derrick is also applied to the framework supporting a drilling apparatus in an oil rig. The derrick derives its name from a type of gallows named after Thomas Derrick, an Elizabethan era English executioner. == Types == There are various types of derrick based on how the tower or mast is set up and the use of boom:〔 File:A-frame derrick.gif|A-frame derrick File:Basket derrick.gif|Basket derrick File:Breast derrick.gif|Breast derrick File:Chicago boom derrick.gif|Chicago boom derrick File:Gin pole derrick.gif|Gin pole derrick File:Guy derrick.gif|Guy derrick File:Guy derrick with nonrotatable mast.gif|Guy derrick with nonrotatable mast File:Stiffleg derrick.gif|Stiffleg derrick File:Kate Derrick 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「derrick」の詳細全文を読む スポンサード リンク
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