If a worker on the outside of a high rise building suddenly falls, their injuries can be pretty severe.

The T-Line Safety System, invented by civil and structural engineer Leigh Dowie, uses a series of pulleys to stop the worker falling far enough to cause harm.

The system looks similar to traditional abseiling equipment, but where it rises above other solutions is in the way it allows workers to move around freely so they can access places that are otherwise difficult to reach.

Thanks to its unique design, the system can be fitted around overhead obstructions such as cranes and pipes. Perhaps one day you’ll be able to use a home version of Leigh’s design to protect yourself when cleaning leaves from your gutters!

How do pulleys make life easier?

Typically, something heavy is attached to one end of a rope, the rope goes over a pulley and you pull up or pull down the other end of the rope.

In that set-up, you’d have to pull down with 100 kg of force to lift a weight 100 kg. The real power of pulleys comes when you loop the rope through multiple pulleys!

The Factory’s Pulley Power exhibit lets you experiment with different numbers of pulleys. With a friend sitting in a chair, see what happens when you try and lift them up using a system of five pulleys. Then, try again using seven. Do more pulleys make it any easier to lift your friend into the air? (Did you have any idea you could be so strong?)

If you have many pulleys linked together, the system uses a longer length of rope. It takes much less effort to pull through the rope on multiple pulley systems, but you need to pass a much longer length of rope through your hands to lift something.

When you use fewer pulleys (say two pulley wheels), you only need to pull on a short length of rope, but it’s much harder to pull the rope.

Learn more

Want to learn more about pulleys? You can download background notes from our page of Educational Materials.