We covered the functions of the wheel pulley in an earlier article, using engineering principles that have been in place for millennia to define the properties of one of the oldest machine parts in the civilized world. This integral part of the pulley system is responsible for the lifting of heavy weights. Simple but amazing principles of physics allow it to function, leaving us to wonder how the timeline of the pulley wheel first developed.
Firstly, just like when observing a circus strongman in action, the wheel pulley is capable of confounding folk with understated power. Apply those laws of physics we already mentioned and you can lift anything. Of course, there has to be a suitably stable lifting frame, ropes or chains, and a number of accompanying pulley wheels, but when these factors are met, huge weights can be lifted and manoeuvred into place.
Here are some examples of the trusty wheel pulley in action:
Lifting is where the wheel pulley truly shines. The first pyramids and the first ships that circumnavigated the world just would not have been possible without the aid of these tiny rounded components. Built as nothing more than grooved wheels, they are the rotating muscle that reside at the heart of lifting mechanisms.
Assembled as a compact lifter, engine hoists typically use a sealed body and a chain feed. On opening this tough body, there’s a series of wheel pulleys packed in grease and oil. The exterior of the chassis is typically comprised of a heavy-duty hook, which has a matching hook at the end of the chain.
Blocks of multi-slotted pulleys guide strong maritime-quality rope through rigging points and up into complex mast assemblies, with little in this configuration having changed over the last four centuries or more. Of course, due to certain laws of energy conservation, the operators that pull the rigging have to possess a little muscle to slide those sails up and down.
Whether talking about an immense railroad maintenance crane or a vehicle-mounted boom, the principle is the same, only this time the wheel pulley is mounted on a suspended block at the end of a mast of crossbeams. Again, laws of energy conservation rule, meaning although drive force is reduced, many meters of looped cable are required to lift heavy loads.
These key examples illustrate the versatile nature of the wheel pulley, showing us how the form is just as important today as when it was first constructed from rickety wood to move the blocks of the pyramids.