Humanity is so familiar with chains – we see them and use them in hundreds of applications throughout our lives – that it may come as a surprise to find that they are a relatively recent invention.
The word “chain” itself is a derivation of an ancient Indo-European word and the earliest known use of a metal chain is that of a well-bucket chain made from linked metal rings back in 225BCE. The use of chains developed alongside humanity’s growing expertise in metalworking and these early chains would have been prized for their vastly superior resistance and longevity compared to the ropes made from animal skins and plant fibres.
Nowadays our industries still make use of chains, although they’ve evolved somewhat! There are heavy duty chains capable of withstanding caustic and abrasive environments, as well as temperatures of up to 530C, such as the chains used in lime production. A far cry indeed from a hessian rope!
Da Vinci’s ideas
Back in the 16th century, genius inventor Leonardo da Vinci made several sketches and plans for what seem to be the first steel chains. These chains appear to have been designed for a pulling application rather than a wrapping application because they have plates and pins only, as well as metal fittings. The sketch does reveal a roller bearing ensemble as well, though, and it’s not dissimilar to bearings used today!
As was often the case with the Italian genius, da Vinci found his ideas were way ahead of their time. The technology to realise and produce the concept was limited by the restrictions on the production and processing of steel itself. Thankfully, innovations in the 19th century made steel manufacture and processing easier and more sophisticated so that it was possible to make chains and bearings much more accurately and uniformly. In 1832, a French inventor called Gull was awarded a patent to make a chain similar to a modern-day bicycle chain and the so-called Gull chain is still used today in hanging and suspension applications.
Chains take off
With the invention of the moulded chain in the 19th century, chain technology started to advance more rapidly. Next in line was the cast-detachable chain, made from cast links that are identical in shape and dimension. Then came the pintle chain, which features a separate pin. Both types of chain, cast-detachable and pintle, have been refined and improved over the decades, as you no doubt imagine and they are still in use today in some industries. They are gradually being replaced, however, mainly by large pitch steel conveyor chains.
By the late 19th century, the bushing came along to change the chain industry further. Chains that featured bushings had much greater resistance to wear then the Gull chains because the bushings provided a bearing to protect the pin. This is when chains really started to develop and to be used in more and more industries and applications. Steel bushing chains were used in bicycles, as well as in the rear-wheel drive of early cars and even in the propeller drive of the Wright Brothers’ 1903 aeroplane.