EN
ZHEN 12278: 2007
Pulleys
Pulleys come in a variety of shapes, sizes and number sheaves, which can be used for different applications. They are mainly used to link a rope or accessory cord to a connector to safeguard a mountaineer, with the main advantage being that it reduces the amount friction to move the rope when under load.
Design
All pulleys are required to have the following as standard:
- An attachment point(s) large enough to accommodate other PPE
- The pulley sheave(s) must be able to accommodate the marked sizes of rope it is designed for
- Pulley shall not have any sharp edges or burrs
- Sheave axle shall be secured by means other than friction.
Strength
To prove that a pulley can work under load, 2 samples with a loop of rope wrapped round are placed under a 2kN load. The loop of rope is then required to be rotated fully in each direction 10 times. Following this test the samples are then taken to breaking point, with the minimum requirement of 15kN or the rated load marked on the pulley, if this is larger than the minimum.