# Understanding the mechanics of dynamic rope brakes

Fuss, F and Gunther, N 2010, 'Understanding the mechanics of dynamic rope brakes', in Sabo A, Kafka P, Litzenberger S, Sabo C (ed.) Proceedings of the 8th ISEA Conference (International Sports Engineering Association), Amsterdam,NL, 12-16 July, 2010, pp. 3323-3328.

 Document type: Conference Paper Conference Papers

Title Understanding the mechanics of dynamic rope brakes Fuss, F Gunther, N 2010 ISEA 2010 Amsterdam,NL 12-16 July, 2010 Proceedings of the 8th ISEA Conference (International Sports Engineering Association) Sabo A, Kafka P, Litzenberger S, Sabo C Elsevier Amsterdam,NL 3323 3328 6 Dynamic rope brakes are integral elements of the standard belaying equipment. They multiply the hand force of the belayer and convert a fraction of the falling climber's kinetic energy into thermal energy. As the rope is deflected by the brake, the thermal energy is produced by belt friction. This paper introduces a brake model based on static and viscous belt friction. The contact angles of three different brakes (figure-of-eight, ATC and HMS [Munter hitch]) were determined. These data as well as data taken and/or derived from the literature served as input for the model. The static and viscous belt friction coefficients range between 0.2-0.3 and 0.015-0.04, respectively, for the three brakes. Depending on the magnitude of the friction coefficients, three conditions can be distinguished: (1) no rope slip at high friction; (2) rope slip and stop; (3) critical braking; and (4) continuous rope slip (no stop). The window of the friction coefficients between no slip and critical braking is independent of the hand force. However, the smaller the hand force is, the larger are the friction coefficients at no slip and critical braking. Belayers with smaller hand forces should therefore avoid rope brakes with small static and viscous friction coefficients (like the Figure-ofEight) and apply the ATC or HMS. Solid Mechanics Sports Technology Sports Engineering © 2010 Published by Elsevier Ltd. 18777058

 Versions Version Filter Type Wed, 09 Nov 2011, 13:49:58 EST Filtered Full
Access Statistics: 27 Abstract Views  -  Detailed Statistics Wed, 09 Nov 2011, 08:09:00 EST by Catalyst Administrator