Your bicycle’s chain is second in importance only to your brakes. So what is the feature of a bicycle chain that allows it to remain serviceable for many thousands of miles? What’s the secret ingredient?
Bicycle chains are properly “bush roller chains.” Hans Renold invented this common bike chain and patented it in Manchester in 1880. This Swiss engineer was born in Aarau, Switzerland (about 30 miles west of Zurich). In 1873 at age 21, Renold found work with a Manchester machinery-exporting firm. In 1879, he purchased a textile-chain business in Salford (14 miles west of Manchester) and, a year later, gave us the gift of the Bush Roller Chain.
In Coventry, about 100 miles south of Manchester, J.K. Starley invented the “safety bicycle” also in 1879. This first replaced the “high wheel” Penny-farthing but with a drive chain unfit for its purpose. The chains were noisy and wore rapidly. The “safety” used the basic diamond shape configuration that survives to the present. This breakthrough in cycling allowed riders to sit lower on the frame and to have greater control of speed, more maneuverability, and ease of stopping.
The Problem – If a chain drive application is in a clean environment, the wearing surfaces are safe from dust, precipitation, mud, and airborne grit. However, as you may have learned from “hands-on” experience, there is nothing on earth dirtier that a bicycle chain. These exposed chains have high rates of wear. This is particularly so when cyclists are prepared to accept more friction, less efficiency, more noise, and more frequent replacement as they neglect lubrication and adjustment. As the chain grinds away on the accumulated grime, it produces a microscopic covering that continues to act like pumice on sprocket teeth and chain links. Thus, your bicycle chain does not really stretch – it just gets longer as the pins and rollers wear.
The Solution –
Roller on fized bushing
Roller on fixed bushing
So what did Renold invent? In his US Patent application he states (as he may well have in his earlier British Patent No. 26805 of 1910): “This invention relates to chains of the silent type, wherein segmental liners are employed engaging in the links and bearing upon the studs, as described for example in the specification of British Patent No. 26805 of 1910. It is the object of the present invention to improve chains of this type by modifications in the construction thereof designed primarily to facilitate lubrication and so greatly to prolong the life of the chains.”
Layout of a roller chain:
- Outer plate
- Inner plate
A Closer Look – So let us dive into a chain and see for ourselves. The layout of a roller chain consists of two outer plates held together by pins. (These immobile pins are what you partially remove to “break” [or open] a chain. Modern chains are opened at a master
link without need of a traditional chain tool.) Within the outer plates is inner plate “sandwich” consisting of bushings staked into the two inner plates and upon each of which rides a freely moving roller – this is Renold refinement.
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You can disassemble a chain further to see for yourself, but the chain link will then be usable. Alternatively, if you look carefully at a slack portion of your chain, you can spin the roller on its bushing with a small pointed instrument (such as a screwdriver). You will not be able to see the bushings as the outer plates, the pins, and the rollers hide them. At this point, you may well appreciate the importance of regular chain lubrication and occasional cleaning. What Renold did was replace sliding friction of pin-and-link chains with their immovable pins rubbing against sprocket teeth by designing a rolling motion thereby reducing noise and wear. While we may now take this simple insight for granted, it ensures that our bicycle chain will perform flawlessly for many miles. Notably, even with patent protection, Renold allowed cycling firms to use his roller chain in their own products without paying royalties.
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A Little History – But what happened to Hans Renold’s firm? His great advance in chain design provided the foundation for modern precision roller chains. Renold was a brilliant engineer and a model employer who built a very skilled labor force. He was also an astute businessman. His business prospered, and he steadily ploughed profits back into it. In 1889, rapid business expansion called for a new factory, Progress Works, which the firm built on Brook St. In 1906, Hans Renold planned and started construction of Renold Works on open land at Burnage, five miles south of Manchester. Renold was devoted to establishing a sense of community among his employees and their families, and, in 1909, gave his active support to the establishment of the Hans Renold Social Union for the encouragement of a wide range of leisure activities. After his death in 1943, Priestnall Hey, his home adjacent to Renold Works at Burnage, went for use by the Social Union. Hans Renold Limited formed as a private limited company in 1903. It merged with The Coventry Chain Company Limited and registered as a public limited company named Renold and Coventry Chain Company Limited in 1930. It was renamed Renold Ltd. in 1967, and later became Renold PLC. The company still bears his name. Today, Renold employs around 2,500 people in more than 23 countries around the world.
So as you cruise silently down the road or trail with a clean and well-lubricated chain, be thankful to the Swiss for their gift to your cycling enjoyment.
USA Bikes + Swiss Brains
- 1864 – The Chain Making Company James Slater (later to become Hans Renold Co.) introduced the roller chain. Prior to this transmission chains consisted of only immoveable pins and plates.
- 1873 – At the age 21, Hans Renold, son of a burgher family in Aarau, Switzerland, came to England and found work in Manchester with a firm of machinery exporters.
- 1879 – His independent and inventive spirit soon found expression in the purchase of a small textile-chain making business in Salford. The Hans Renold Co. established following the purchase of the James Slater business. This makes Renold the oldest transmission chain company still in existence in the world.
- 1880 – Introduced the patented his famous solid bush around which the roller spun. This was the origin of the bush roller chain, the design of which is still in use today throughout the world. Thus began the enterprise of which The Institution of Mechanical Engineers was to say in a memoir: “Few realize how extensive is the influence of Renold’s inventiveness on both civil and industrial life throughout the world. Hans Renold’s vision was not restricted to the prospects in UK industry, and over the following years, he began the international expansion of his company.
- 1885 – Hans Renold applied for a patent for the block chain but he decided to give his idea to the cycle trade for all to manufacture freely. Brampton Brothers Co., who later became part of the Coventry Chain Company (and ultimately Renold Chains Ltd.), experimented with self-lubricating bicycle chain.
- 1888 – Began riveting the bearing pins in the assembled chain.
- 1889 – Designed and manufactured a purpose-built plate hole-punching machine. Designed and manufactured a machine for the dry tumbling (jingling) of chain components.
- 1893 – As early as 1893, begins using hardened components.
- 1895 – Designed and manufactured a machine for producing the rotary rivet on the ends of the chain bearing pins. The need for an Inverted tooth (silent chain) was apparent to Hans Renold and this resulted in his patent of 1895. Although his design of chain was superseded in later years by the silent chain with rocker joints, he made an impact in the introduction of such a chain. Hans Renold Co. designed and manufactured a machine for the wet tumbling (jingling) of chain components.
- 1896 – Designed and manufactured a machine for the proof loading of chains. Introduced the 48-hour week when the general practice in engineering was 52 or more.
- 1899 – Introduced patented feature of the end recess in the bearing pin. Brampton Brothers Ltd. patented the integral bush/inner plate chain upon which so many cycle chains were have been based. Introduced a Works Canteen. Introduced the round-ended necked (i.e., shouldered) bearing pin in their 1899 patent.
- 1900 – Designed and manufactured a coning machine (which tapers the end of a metal tube or rod to facilitate insertion elsewhere).
- 1903 – Hans Renold Ltd. formed.
- 1905 – Introduced percussion testing on chain components. Designed and manufactured a semi-automatic drifting (hole punching) machine for use on assembled inner links.
- 1906 – Began supplying mortise block chains (and associated equipment) which was a notable part of the business for 60 years. During the construction of a new factory (rather than using belt drives from overhead line shafts), designed and installed overhead chain drives. Began designing and manufacturing special-purpose machines for the assembly of chains. Began the manufacture of chain wheels. Developed a machine for centerless grinding of bearing pins. This was long before centerless grinders became the factor in machine shop practice. The Coventry Chain Company Ltd. (who later became part of the Renold group) patented the helical (spiral) roller formed by a wire strip.
- 1907 – Developed a new tooth form for roller chain wheels.
- 1909 – Introduced torsion testing on chain components. Began supplying transmission chain for Aircraft. Hans Renold founded the Hans Renold Social Union.
- 1910 – Designed and manufactured a tumbler (jingler) for polishing and bluing chain plates. The blued plates were a feature of the Hans Renold chain for many years.
- 1912 – Began the process of end softening of bearing pins. Supplied the chain for The Great Clock at the Palace of Westminster known more affectionately as “Big Ben” (built 1856).
- 1913 – Gave the world an improved sprocket tooth profile that, with slight modification, the United States adopted as a standard profile. Designed and manufactured a fatigue test machine for the evaluation of chain fatigue strength.
- 1914 – Designed and patented their flexible chain coupling – a product still in use worldwide.
- 1915 – Manufacturing high-waisted chain plates and chains with straight-sided plates. Designed and manufactured running-in machine for their chain. Introduced stock drives that are taken for granted today.
- 1916 – Supplying chains with case-hardened pins. Patented the segmental bush design of inverted tooth (silent) chain. Around 1916, The Coventry Chain Company Ltd. developed and manufactured track chains for use on tank vehicles. (From late 1914, a small number of middle-ranking British Army officers tried to persuade the War Office and the Government to consider the creation of armored vehicles. Amongst their suggestions was the use of caterpillar tractors, but although the Army used many such vehicles for towing heavy guns, it could not be persuaded that they could be adapted as armored vehicles. The consequence was that the Royal Navy carried out early tank development in Great Britain.)
- 1917 – Still leading the world by having coned (i.e., tapered) bush bores in 1917. The first coning machine designed and manufactured in May 1900.
- 1918 – Manufactured extra strong chains for use on motor cycles
- 1922 – Designed and manufactured a bush-curling machine.
- 1925 – The first acquisition of a major competitor with purchase of Brampton Brothers Limited, with its French manufacturing subsidiary at Calais. Operation merged with the manufacturing facility previously established in Coventry.
- 1927 – To improve bush inner/plate security, patented the ‘keyed’ bush. This feature is still used today. Approved under the AID regulations to issue inspection certificates and likewise approved as an ARB inspection authority.
- 1930 – Merger created Renold and Coventry Chain Co. Ltd.
- 1932 – Chain now has chamfered plates some being double chamfered (i.e., both sides). Renold and Coventry Chain Co. Ltd patented the early design of bi-planar chain (applied for patent in 1928).
- 1933 – Supplied chain with a notched bush.
- 1943 – Hans Renold dies.