Science Fair Project Encyclopedia
Derrick (lifting device)
A derrick is a lifting device composed of one mast or pole which is hinged freely at the bottom. It is controlled by (usually 4) lines powered by some such means as man-hauling or motors, so that the pole can move in all 4 directions. A line runs up it and over its top with a hook on the end, like with a crane. It was commonly used in docks.
The device was named after Thomas Derrick, an English executioner from the Elizabethan era because of its resemblance of the frame from which a hangman's noose hangs.
Derricks over drilled holes
Santa Barbara, California — oil derricks on the beach in 1900
Another kind of derrick is used over oil wells and other drilled holes.
Last updated: 05-25-2005 15:42:16
10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details