Clamping knot

Clamp knots are knots that attach a line to a standing line in such a way that they lock themselves when pulled. Usually they can be moved along the standing line when the load is removed.

The tensile force is mainly applied in the axial direction to the rope or rope under tension or load by a second rope to be attached .

Mode of action and use

Visible deformation after untying, caused by a clamping knot that was under load.

The mode of operation is based on a clamping effect. The more the knot is loaded, the more it pinches the jammed rope in between. The many trips on which most of the clamping knots are based are noticeable . With a larger number of trips, a stronger holding force can be achieved with many clamping knots. A special feature of the clamping knots is that they reliably open again after a load. This is also increasingly guaranteed as the number of trips increases. Too many turns make most clamping knots unstable, however, the optimal number of turns depends on the thickness of the knot rope to be knotted, for which there are empirical variables depending on the use.

The area of ​​application is versatile and relates to all those who are associated with ropes, for example:

• Sailing ships
• Reliably traceable step loops : Mountaineering (self-rescue from the crevasse, ascent on the open rope and the like)
• Technical climbing / tree climbing (SKT)
• Cave climbing with single rope technique (SRT) and other special climbing techniques

Examples

Single-strand loaded clamping knots

• 

  Stopperstek

• 

  Tarbuck knot & loop

• 

  Blake knot or Prohaska with loop

• 

  Icicle steak

• 

  Ashley (# 1740)

In the Ashley book of knots there is a single-strand loadable knot under number 1740.

It starts with two turns (windings) around the standing part downwards, then crossing the two windings upwards. Again two more trips upwards in the same direction of rotation. Then the end under the crossover is pushed back through descending parallel to the starting point. At the end it still has to be tightened to ensure initial friction. If the knot shifts on an initial test load, tighten it more. Tighten the rope end and the parallel counterpart alternately. If the tightly knotted knot is loaded, however, it pinches (jams) itself strongly and even deflects the standing part, depending on the rope material and load, up to a maximum of right angles, e.g. B. when a load change occurred or the previously loaded rope is cut.

Two-strand loaded clamping nodes

• 

  Prusik knot

• 

  FB tape clamping knot

• 

  Carabiner clamp knot

• 

  Machard "Blocker" node

• 

  Cross clamp knot

• 

  FB cross clamp

• 

  FB-Prusik

• 

  Swabian clamping knot

• 

  Thistle knot

• Howard-Hitch

Dangers when using a clamping knot as a replacement for a rope clamp

Although the function of a clamp knot is similar to that of a rope clamp , it is not advisable to use a clamp knot for self-belaying when climbing solo. If the knot cannot be pushed any further because both hands are needed to hold and climb, a slack rope is created, which in the event of a fall leads to a high load on the clamping knot. The knot then does not block immediately, but continues to slide. The resulting melt burn can be enough to destroy the cord, which leads to the climber falling.

Web links

• Ascender Knots
• Are clamping nodes still state of the art (PDF file; 25 kB)
• Adjustable Bend, an adjustable clamping knot
• Clamping knot also on the steel cable; Franz Bachmann , Italian contribution. (accessed on February 16, 2013)

Individual evidence

1. ↑ Schwabisch Hitch: How to tie the Schwabisch Hitch Knot. Retrieved September 11, 2018 . 
2. ↑ Howard Hitch a new clamp knot in the test laboratory. (PDF; 151 kB) Retrieved January 16, 2016 . 
3. ^ Pit Schubert: Safety and Risk in Rock and Ice , Bergverlag Rother, Volume 1, 7th edition, 2004, ISBN 3-7633-6016-6 , p. 141