Carabiner

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Clockwise from top left: D-shaped wire gate, D-shaped straight gate, Oval straight gate, Pear-shaped auto-locker, D-shaped screw-locker. Center is a standard carabiner rating.

A carabiner (/kærəˈbnər/) or karabiner is a metal loop with a spring loaded gate[1] used to quickly and reversibly connect components in safety-critical systems. The word is a shortened form of "Karabinerhaken", German for "spring hook for a carbine".[2]

History[edit]

Otto Herzog in 1911 was the first climber to have used the carabiner device based on the "pear" used by the firemen of Munich. Use of the climbing carabiner was actually a logical consequence of the use of piton invented by Hans Fiechtl and tested by Hans Dülfer, although climbers as prestigious as Paul Preuss or Eugen Guido Lammer were opposed to any artificial process. Still, Dülfer, Fiechtl and Herzog commonly employed carabiners on the eve of the World War I and from 1921 a model of a unit weight of 130 grammes for climbers, was made in Munich. The carabiner has been improved several times over the decades, making it more lightweight, reliable and durable.

Use[edit]

Carabiners are widely used in rope-intensive activities such as climbing, arboriculture, caving, sailing, rope rescue, construction, industrial rope work, and window cleaning. They are made from both steel and aluminium. Those used in sports tend to be of a lighter weight than those used in commercial applications and rope rescue. Carabiner-style keyrings have also become popular, most stamped with a "Not For Climbing" warning.

Physical properties[edit]

Shape[edit]

Carabiners come in four characteristic shapes:

  1. Oval: Symmetric. Most basic and utilitarian. Smooth regular curves are gentle on equipment and allow easy repositioning of loads. Their greatest disadvantage is that a load is shared equally on both the strong solid spine and the weaker gated axis.
  2. D: Asymmetric shape transfers the majority of their load onto the spine, the carabiner's strongest axis.
  3. Offset-D: Variant of a D with a greater asymmetry, allowing for a wider gate opening.
  4. Pear/HMS: Specialized oversized offset-D's used in belaying. These are usually the heaviest carabiners.

Locking mechanisms[edit]

There are three broad categories of carabiner: auto locking, manual locking, and non-locking.

Non-locking[edit]

Non-locking carabiners have a sprung swinging gate that accepts a rope, webbing sling, or other hardware. Rock climbers frequently connect two non-locking carabiners with a short length of nylon web to create a quickdraw.

Three gate types are common:

  1. Straight gate: The most utilitarian, and hence most popular.
  2. Bent gate: Curved gates allow for easier clipping in and out in special situations, such as connecting a rope to a quickdraw. Gate strength remains on a par with straight-gate carabiners.
  3. Wire gate: The lightest type, with a strength roughly equal to the others, allowing more to be carried for a given weight. Wire gates are less prone to icing up than solid gates, an advantage in Alpine mountaineering and ice climbing. The reduced gate mass makes their wire bales less prone to 'gate flutter,' a dangerous condition created by irregular impact forces generated by the climbing rope or contact with hard surfaces in a fall which momentarily opens the gate (and both lowers the breaking strength of the carabiner when open and potentially allows the rope to escape).

Locking[edit]

Locking carabiners have the same general shape as non-locking carabiners but have an additional mechanism securing the gate. These mechanisms may be either threaded sleeves ("screw-lock"), spring-loaded sleeves ("twist-lock") or magnetic levers ("Magnetron").

Certification[edit]

Europe[edit]

Carabiners are marked on the side with single letters showing their intended area of use, for example, K (via ferrata), B (base), and H (for belaying with an Italian or Munter hitch).

United States[edit]

American National Standards Institute/American Society of Safety Engineers standard ANSI Z359.1-2007 Safety Requirement for Personal Fall Arrest Systems, Subsystems and Components, section 3.2.1.4 (for snap hooks and carabiners) is a voluntary consensus standard. This standard requires that all connectors/ carabiners support a minimum breaking strength (MBS) of 5,000 lbf (22 kN) and feature an auto-locking gate mechanism which supports a minimum breaking strength (MBS) of 3,600 lbf (16 kN).

See also[edit]

References[edit]

  1. ^ "Climbing Dictionary & Glossary". MountainDays.net. Retrieved 2006-12-05. 
  2. ^ http://www.etymonline.com/index.php?search=Karabiner