Braking resistance (mountain sports)
The braking resistor in sport climbing is a mechanical device that is attached to the first bolt of the intermediate safety device along with a safety rope in addition to the safety device or the rope brake in order to intentionally increase the rope friction. As a result, in the event of the lead climber falling, a further part of the impact force is absorbed by friction, and the fall tensile force arriving at the belaying partner is reduced. In particular, a belaying partner who is lighter than the climber will be less accelerated upwards when belaying the body. The hand holding force to be applied behind the belay device is also reduced.
In this way, the safety-related consequences of a larger weight difference in a rope team can be compensated for.
The increase in friction also works when the climber is lowered and is therefore also helpful when top rope belaying.
Device types
Devices with static braking effect
Devices with a static braking effect increase the friction through multiple small deflections of the rope around round metal cams, according to the Euler-Eytelwein formula . Since the wrap angles remain constant, the frictional force is proportional to the pulling force at all times. This means that the rope can be moved with less friction during regular pulling, the higher force of the fall pull generates significantly higher friction, the force of which is introduced into the intermediate securing system.
Devices with dynamic braking effect
Devices with a dynamic braking effect increase the friction depending on the situation. They have an angle-dependent clamping device. As long as they hang down due to their own weight, the rope can pass almost unhindered when pulling slowly. However, a quick upward movement of the rope pulls the device with it, the clamping device begins to grip and increases the drag effect. In the upper position, the clamping device now brakes the camber pull and thus introduces a partial force into the intermediate securing device.
A representative of this braking principle is the "Ohm" braking resistor from Edelrid GmbH . The product name was chosen based on the unit ohm of electrical resistance.
Individual evidence
- ↑ Jörg Helfrich, Julia Janotte and Florian Hellberg: Weight differences when belaying - heavier? And if so, how much? . - DAV Panorama, year 2016 issue 6, pp. 52–55
- ↑ Bauer rope brake - product description. BauerAndMore: Pfungstadt, 2016. Retrieved 2017-02-23
- ↑ Jan Hoffmann, Sebastian Straub, James Heath: Belay Device Handbook . Edelrid: Isny im Allgäu, 2nd edition 2017.