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The Carabiner

Sunday 1 January 2017, by Imeru Alfonzo Hernandez

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Origin and uses

The carabiners or carabineros were initially used to connect the war equipment, sword, muskets, carbines, etc. to the body of the combatants, hence its name is derived. This accessory was later used to connect other types of equipment, including those used in non-military activities, such as speleology and mountaineering.

The carabiner is a metallic ring or link that is kept closed thanks to a trigger or pivoting door attached to a spring or spring.

There are many types and variations according to each manufacturer, but all of them comply with the basic principle of connecting various equipment or ropes. They are generally classified as Individual Protection Equipment (IPE), but in this article only safety carabiners will be considered PPE.

There are many types of carabiners, but mainly divided into two groups, the simple carabiners and safety carabiners, below will be the most outstanding characteristics of these.

Simple carabiners

They are characterized by being light and resistant, although they can not be used for places where it is considered that there is a danger of accidental opening. There are basically three types of these, the straight door, the curved door and the wire gate, or ultralight. It is important to note that these ultra-light carabiners are not recommended for activities with high risk of sudden traction, and this is also prone to facilitate the accidental disconnection of the rope in rock climbing or making artificial routes.

Security carabiner

It is a carabiner to which an automatic or threaded closure has been added, to prevent the pivoting door from opening accidentally. They are used in conjunction with other PPE and in anchors, places where safety must come first.

Main features

Its construction is mainly made of aluminum or steel alloys, although titanium is used for special products. The most important thing when choosing between one or another material is the resistance and the weight. Although, the steel ones are generally more resistant, the additional weight makes them unattractive when they must be loaded for great distances.

The parts of a carabiner are basically six, the body, composed of the alloy bar, is the component that provides resistance to this device. It supports mainly the longitudinal tensions thanks to a thermal treatment that makes it more resistant, but this same treatment that gives it strength, also makes them fragile and prone to break before a fall or hit against another object.

The following diagrams show the parts of a safety carabiner, six in total, and indicate their main resistance axes and the width of the opening.


2. Door or Trigger

3. Hinge with spring

4. Closing hook

5. Safe

6. Resistance and norm

7. Longitudinal shaft

8. Cross section

9. Maximum openness


The main feature of this element

Resistance is the ability of the carabiner to withstand loads or tractions, static and dynamic, without suffering a permanent deformation (plastic deformation), so it is highly recommended to know the use of the carabiner before deciding to use a specific model. .

The unit used is Newton (N), which is a unit of force, which is exercised by accelerating 1 meter over a square second to a mass of 1 kg.

1Kg * 1m / s2 = 1N

The measure currently used by manufacturers is the Kilo Newton (KN) which is equivalent to 1000 newtons of force. These resistances vary according to the model used, but usually range from 22 to 45 KN on the longitudinal axis, more resistant, and between 6 and 12 KN on the transverse axis.

Another resistance that must be considered is with the open closure, and this is of special importance when using simple carabiners, which are prone to open up to a violent traction effort.

According to PPE Directive 89/686 / EEC, which classifies all PPE (Personal Protective Equipmen) materials, they must have the maximum recommended strengths or tolerances, the CE mark and a manual of use and care in several languages. Some may use the UIAA standards system, which is more demanding than the CE, but worldwide is less adopted by the manufacturer. The most common resistances are shown in the following table.

Axis Load
Longitudinal (closed) 20-35KN
Transversal (closed) 6-12KN
Longitudinal (open) 6-12KN

Form of the Carabiners

There are as many different forms as applications, some versions are multipurpose, others are exclusively for a specific activity, the following paragraphs show their main forms and applications.


As the name implies, they have the same shape and features for the ends of their axes, they are designed to be used in anchors, application knots, hoists and pulleys.

The two predominant forms in the designs are the oval (figure A) and the square, which is a variation of the oval with a significant reduction in the radius of curvature of its ends.


Mosquetones Asimétricos

They are made up of the vast majority of models that are manufactured on the market, these are intended for specific applications and sometimes it is counterproductive to use them for tasks for which they were not designed. They are of great opening and high resistance, the most used forms are:

Form H or HMS (figure B), is mainly used to pass a rope with a dynamic knot or UIAA by the. This serves to secure a climber to the rope (first of rope), hoist or descend to a partner or a load. Another important use is the connection with a type eight descender or equivalent.

Pear shape (figure E), they are ideal to connect to structures, anchors and meetings, they are a modification of the HMS to increase their opening, this allows them to be used in via ferratas and adventure park. The result of these modifications has given this carabiner a greater resistance to the previous one.

Asymmetric D and D shapes (figures C and D resp.), Are the most resistant and are used mainly in main anchors and where additional security is needed, their shape directs the greater effort towards the main bar, which is the most resistant component of the carabiner, and avoid excessive loading around the door or trigger

(C) 2007 Imerú Alfonzo Hernández, All rights reserved, may use the texts and images presented in this article, provided that the original source is cited.