48 POWER TRANSMISSION
Roller chain drives offer longer life, even in harsh environments
Roller chains have evolved a long way since Leonardo da Vinci sketched his ideas in the 16th century and Hans Renold invented bush roller chain in 1880. Jon Severn takes a look at some of the latest developments in power transmission and conveyor chains, as well as chain attachments and chain- monitoring sensors.
Les chaînes à rouleaux ont bien évolué depuis les esquisses de Léonard de Vinci au XVIe siècle et l’invention de la chaîne à douilles en 1880 par Hans Renold. Jon Severn examine les nouveaux développements dans le domaine de la transmission de la puissance et des chaînes de convoyeurs, ainsi que les accessoires pour chaînes et les détecteurs de surveillance des chaînes.
Rollenketten haben eine lange Entwicklung hinter sich, seit Leonardo da Vinci seine Ideen im 16. Jahrhundert gezeichnet und Hans Renold 1880 die Hülsenkette erfunden hat. Jon Severn untersucht einige der neuesten Entwicklungen bei Kraftübertragungs- und Förderketten, sowie Kettenbefestigungen und Kettenüberwachungs- sensoren.
C
hain transmission systems have been eclipsed by timing belts for many applications today, thanks to the developments in materials and tooth
form that have resulted in stronger and more reliable toothed belts with higher efficiencies. But for applications in harsh environments or where there is limited space available to transmit the required power, roller chains still have a role to play. Moreover, this is an area where product development is continuing, even though Leonardo da Vinci sketched roller chains in the 16th century and they have been mass-produced since the late 19th century. Recent developments have focused on both
power transmission and conveyor chains, often targeting applications in extreme environments – where elevated temperatures and corrosive substances are encountered – as well as those where cleanliness is important, such as in the food and beverage industries. For the majority of applications, however, the
main drawback with roller chain is wear in the chain and sprockets, which leads to the chain lengthening (often misleadingly referred to as ‘stretching’) and, eventually, the need to replace the chain and maybe the sprockets too. In a bid
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Fig. 1. Fenner Plus transmission roller chain features solid rollers with high surface hardness, which results in improved wear resistance and longer life.
to combat this problem, companies such as Eriks have been investigating ways to improve the wear characteristics of roller chains. Eriks’ Fenner Plus range of transmission
roller chains, for example features solid rollers that are manufactured to have an extremely high surface hardness that improves wear resistance. This results in longer life for the chain in less demanding applications, as well as better performance in hostile environments (Fig. 1). Shot-peened plates help further in extending
the chain’s life, as this process relieves the stresses built up during manufacture and reduces the likelihood of fatigue failures. In addition, since the chain plates are punched progressively, hole concentricity and the accuracy of both the diameter and pitch are maintained along the entire length of the chain. This ensures quiet and accurate meshing with the sprockets and eases pin extraction when splitting the chain. Another feature that helps to minimise wear is the case-hardened chain pins, and the Fenner
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