The development of chain technically began in 225 B.C. when Philo described a chain driven water lift, similar to modern bucket elevators. Leonardo da Vinci was responsible for the next notable developments, when he sketched designs in the 1500’s. His sketches bear a remarkable resemblance to modern bar link, leaf and silent running chains.
In the 16th century, Ramelli found the first practical application for chain, in the development of water driven pumping systems. However, it was the industrial revolution of the 1800’s that began the development of chains we still use today.
The first largely adopted chain was called a ‘cog’ chain, as it ran over a sprocket or ‘cog’. Based on a rectangular cast link design connected by looped and riveted iron bands, the design was simple, but difficult to repair without specialist tooling. ‘Cog’ chain was used to transmit power and motion from treadmills to an array of other equipment, such as water elevators, farm machinery and weaving looms, to name a few examples from the early 1800’s.
The introduction in 1873 of cast detachable chain overcame most of the problems associated with ‘cog’ chain. The chain was of a simple construction, using identical cast links which could easily be coupled and uncoupled by hand. Cast chain saw rapid adoption in the agricultural industry, transmitting horse drawn power to various different types of equipment. It did not take long for adoption to spread to other areas of industry, with a malleable iron or steel version of this chain still used heavily in the agricultural industry today.
By the late 1800’s, manufacturers had developed cast attachment links enabling iron buckets to be attached. When used vertically, this assembly became the first bucket elevator, with manufacturers offering elevator systems by the 1890’s. Apron conveyors were produced by bolting slats or flights to the attachments rather than buckets, enabling bulk materials to be conveyed horizontally or up mild inclines. For steeper inclines, the attachments could be used for scraper flights, creating the first drag conveyors.
The next development after cast detachable chain was the introduction of cast pintle chain. By utilising a ‘closed barrel’ design, stronger link plates and a steel pin or ‘pintle’, this chain became the first ancestor to modern engineered roller chains. Developed to withstand higher speeds, heavier loadings and more severe operating environments, this chain leant itself for use in both drives and conveyors.
It was not long before conveyor manufacturers developed this chain with a larger pitch. Not only did this reduce the number of joints, but it also allowed more space for larger attachments or more complex designs. It was found that the addition of hardened steel bushings increased the chains resistance to wear, with the later addition of a rollers revolving around this bushing greatly reducing loading due to sliding friction.
With automation and standardisation came a move away from cast pintle chain towards precision steel roller chain. Manufacturing equipment such as punch presses and automated machinery enabled high speed production of quality components and therefore reliable chains. Standardisation began as early as 1913, with the precision roller chain industry being one of the first to standardise. This ensured that chains and sprockets from different manufacturers were guaranteed to be interchangeable, with the ASME B29.1 standard appearing in 1930.