Chain

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Part of The Great Chain at West Point.

A chain is a series of connected links, usually made of metal. Chains are made for various purposes and therefore come in different shapes and styles. For example, some chains are designed for lifting (as with a hoist) or pulling a load, or for securing against theft (such as when securing a bicycle). Such chains have links that are torus shaped. Other chains are designed for transferring power in machines, conveyor belts, bicycles, and motorcycles. Such chains, known as roller chains, have links that mesh with the teeth of appropriately designed sprockets.

Contents

Chains can also be used for decorative purposes, as in jewelry. On a somber note, chains have also been historically used as devices to hold slaves and prisoners under restraint.

A broad metal chain made of torus-shaped links.
Roller chains.
Roller chain and sprocket.

Types of chains and their uses

There are various types of chains designed for various uses. A number of them are listed below.

  • Ball and chain: It refers to a restraining device used to slow down prisoners.
  • Bicycle chain (or chain drive): This chain transfers power from the pedals of a bicycle to the drive-wheel, thus propelling the bicycle. It is the main distinguishing feature of the safety bicycle. Based on its shape and function, it is classified as a roller chain.
  • Bicycle locking chain: It is a chain used for locking a bicycle to a stationary post.
  • Chain gun: It is a type of machine gun that utilizes a chain, driven by an external power source, to actuate the mechanism rather than using recoil.
  • Chain link fencing: This type of fencing utilizes vertical wires that are bent in a zig-zag fashion and linked to each other.
  • Chain-linked Lewis: This is a lifting device made from two curved steel legs.
  • Chain of office: It is a collar or heavy gold chain worn as an insignia of office or mark of fealty in medieval Europe and the United Kingdom.
  • Chain pump: It is a type of water pump where an endless chain has circular discs positioned on it.
  • Chainsaw: It is a portable mechanical, motorized saw, commonly used in logging activities such as felling, limbing, and bucking.
  • Chain-shot: It is a type of ammunition for a cannon, used to inflict structural damage to a vessel during naval warfare.
  • Chain weapon: This medieval weapon was made of one or more weights attached to a handle with a chain.
  • Curb chain: It is used on curb bits when riding a horse.
  • Door chain: It is a type of security chain on a door that allows one to open a door from the inside while making it difficult for someone outside to force his or her way in.
  • Flat chain: This form of chain is used chiefly in agricultural machinery.
  • Jack chain: This toothed chain is used to move logs.
  • Jewelry: Many necklaces and bracelets are made of small chains of gold and silver.
  • Keychain: This small chain connects a small item to a keyring.
  • Ladder chain: It is a light wire chain used with sprockets for low-torque power transmission.
  • Lead shank (or "stud chain"): It is used on difficult horses that are misbehaving.
  • Leg iron chains (or fetters): They are used as an alternative to handcuffs.
  • Nunchaku: It is the name for karate sticks linked by a chain.
  • Omega chain: It is a pseudo-chain in which the "links" are mounted on a backing rather than being interlinked.
  • O-ring chain: It is a specialized type of roller chain.
  • Pull switch: It is an electrical switch operated by a chain.
  • Roller chain: This type of chain is most commonly used for the transmission of mechanical power in bicycles, motorcycles, and industrial and agricultural machinery.
  • Snow chain: It is used to improve traction in the snow.
  • Timing chain: It is used with an internal combustion engine, to transfer rotational position from the crankshaft to the valve and ignition system, typically with a 2:1 speed reduction.

In addition to the above uses, some people wear wallets with chains attached to their belts, or pants decorated with chains. At times, a chain is used as a percussion instrument for special effects, such as in Schönberg's "Gurre-Lieder" and Janáček's "From the House of the Dead." Also, chains have been used to prevent the passage of ships through waterways, as was done with the Hudson River Chains during the American Revolutionary War.

See also

References

  • American Chain Association. 2006. Standard Handbook of Chains: Chains for Power Transmission and Material Handling, 2nd edition. Boca Raton, FL: Taylor & Francis. ISBN 978-1574446470.
  • Ballantine, Richard. 2001. Richard's 21st-Century Bicycle Book. Woodstock, NY: Overlook Press. ISBN 1585671126.
  • Kanehira, Makoto, and Kyosuke Otoshi. 1997. The Complete Guide to Chain. Wheeling, IL: Tsubaki. ISBN 0965893200.
  • Waszek, Glen F. 2001. Making Silver Chains: Simple Techniques, Beautiful Designs. New York: Lark Books. ISBN 1579901832.

External links

All links retrieved April 29, 2013.

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