Pulley (Pulley system)
| Pulley | |
|---|---|
 | |
| Other names | Pulley system |
| Use(s) | Rope support, rescue techniques, hauling |
 | Review state This page has not been reviewed yet (review state explanation). |
In climbing and mountaineering pulleys are used mainly in rescue techniques. Sometimes they are employed during hauling.
Principle of operation
Pulley systems are simple machines used to lift heavy burdens. Image on the left describes 2-to-1 pulley. With this pulley, it takes roughly half of the force to lift the weight. But to lift the weight by 1 meter, you must take 2 meters of the slack as illustrated by arrows and colored parts of the rope.
3-to-1 (2-to-1) Pulleys
In most cases, these pulleys cannot be used for lifting a full-body weight by a single person. However, they work way faster than the higher-ratio pulleys. Therefore, they are mainly used when the lifted person helps with the pulling and for hauling.
Rope-support
Crevasse self-rescue
TODO
5-to-1 (4-to-1) Pulley
These pulleys distribute the force in a way that lifting a person is possible without assistance. However due to the ratio the speed of lifting is very low and in some cases there is substantial friction from the amount of bends in the pulley system.
Rescue
TODO