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Using carabiners as pulleys

Tuomas Pöysti 2020 Once again, this is not a very practical article. Not a single photo. And I’m not going to give much direct answers or advice, but hopefully this will help someone coming into their own conclusions. Using pulley system analysis, we can systematically study some properties of different pulley systems. For example, we […]

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Pulleys: where is the friction?

We know that a good, relatively big pulley used with a 11mm nylon rope is actually only about 90% efficient. That is, 10% of energy is lost somewhere around the pulley. And a smaller pulley will lose even 20%. For example: if a 100kg weight is lowered 10m distance using a descender, the descender has […]

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My method of measuring pulley efficiency

Tuomas Pöysti 2020 In the realm of rock climbing, rope access and other disciplines that use fairly similar equipment, there seems to be no “industrial standard” for measuring pulley efficiency. Surely the whole thing is not that big a deal, even though every textbook that has something about pulley systems tend to mention that pulleys […]

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Limitations of simple pulley systems

Tuomas Pöysti 2020 I tend to focus on the theoretical aspects of pulley systems, so no practical tips should be expected. I think, though, that there are many interesting explanations to real life phenomena to be found, if one just scratches the surface of physics and mathematics around pulley systems. If my terms, methods or […]

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Pulley system analysis

Tuomas Pöysti 2020 As I wrote in the introductory article about pulley systems, pulley systems are commonly named after their ideal mechanical advantage (MA) value, which on the other hand is usually very different from the effective MA value. The T-method To find out both values for a pulley system, the first thing to do […]

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Articles in English

Pulley system basics

I’m into pulleys and pulley systems. If you read my articles about them, you might find me accidentally diving a bit deep sometimes, but I try to keep this text as simple as possible. Pulley systems are like bicycle gears. They are able to exchange between speed and force. According to basic principles of mechanics, […]