Derrick

For other uses, see Derrick (disambiguation) and Derricks (disambiguation).
Two guy derricks at a granite quarry

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 to both 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.[1][2]

Derricks are especially useful for high-rise rigging, jobs that cover a long period of time, or jobs when the impact to street or pedestrian traffic is a concern.[3] Forms of derricks are commonly found aboard ships and at docking facilities. Large derricks mounted on dedicated vessels are known as floating derricks[4] and shearlegs.

The term derrick is also applied to the framework supporting a drilling apparatus in an oil rig.[5] The derrick derives its name from a type of gallows named after Thomas Derrick, an Elizabethan era English executioner.[6]

  1. ^ Australia, Emergency Management (2006). General and disaster rescue skills for emergency services personnel (PDF) (5th ed.). Dickson, A.C.T.: Emergency Management Australia. pp. 131–132. ISBN 1921152028. Archived from the original (PDF) on 21 March 2014. Retrieved 5 July 2014.
  2. ^ "Regulations (Standards - 29 CFR) - 1910.181: Derricks". Occupational Safety and Health Administration. Retrieved 5 July 2014.
  3. ^ "Derricks". Budco Enterprises, Inc. Retrieved 2016-06-10.
  4. ^ "Subchapter 7. General Industry Safety Orders; Group 13. Cranes and Other Hoisting Equipment; Article 91. Definitions". Department of Industrial Relations, State of California. Retrieved 5 July 2014.
  5. ^ Freudenrich, Craig; Strickland, Jonathan (12 April 2001). "How Oil Drilling Works". HowStuffWorks. Retrieved 5 July 2014.
  6. ^ Forsyth, Mark (2012). The etymologicon : a circular stroll through the hidden connections of the English language (Berkley trade pbk. ed.). New York: Berkley Books. p. 60. ISBN 978-0425260791. Retrieved 5 July 2014.