Let’s imagine that for one reason or another the location where the input effort is required to be applied is far away from the location of the load.
In the example below we have a small load weighing 10kg. The load only needs to be lifted to a height of 1.0m but due to the nature of the environment the effort required to lift the load will need to be applied from a remote point. We could easily go all in and attempt this without any pulleys.
We seem to be getting there but we do have a problem. At any point where the rope comes into contact with the edges of the tunnel there is a huge amount of friction caused by the rope running over the surface. Not only will this require a larger input effort to be applied but as we’re using a soft textile rope we can’t expect this system to hold up for very long before the rope gives up and breaks!
All we need to do is to construct a system that uses pulleys to change the path of where the effort needs to be applied. To do this, firstly we need to connect the rope to the load that requires moving. Secondly we need to give the rope a route back to where the input is going to be applied, avoiding contact with the edge and surfaces.
Due to the bends within the structure we are going to install a few pulleys into the system. By adding the pulleys we are reducing the amount of friction within the system, making it easier for the operative to move the load and also protecting the rope from the abrasive edges of the tunnel.