Visit the ExxonMobil Lubricants and Specialties Europe web site

Chains combine capacity with ruggedness

Edited by the Engineeringtalk editorial team May 8, 2003

When drives need to move very heavy equipment and withstand shock loads, designers usually choose Super and Ultra-Super class drive chains to do the job, says Bob Young of Tsubaki UK.

When drives need to move very heavy equipment and withstand shock loads, designers usually choose Super and Ultra-Super class drive chains to do the job, says Bob Young of Tsubaki UK.

In demanding applications such as quarrying, conveying, bulk handling and mobile drive systems where standard roller chains are beyond their limits, there is a demand for a class of chain offering higher load capacities greater resistance to shock loads, together with the fatigue strength needed to sustain reliable operation for long periods of time.

Increasingly, Tsubaki's Super and Ultra Super series of chains, which have been developed to withstand the most rugged operating conditions, are satisfying these demands.

Because of the applications for which they are used, Super and Ultra-Super class drive chains frequently operate around-the-clock, and are often subjected to mud, sand, metal particles, and other abrasives.

In addition, they handle intermittent shock loading, and operate with minimal maintenance and lubrication.

Applications for Super class chains exist in many heavy industries.

Their rugged construction means that they are used to transmit power to a wide variety of equipment including agitators, compressors, crushers, elevators, fans, hoists, rotary kilns, machine tools, rotary mills, mixers and pumps.

Common applications include turning heavy rotating drums, such as barking drums in pulp mills, ball mills in ore processing, or shakeout drums in foundries.

The chains also power large off-road cranes and draglines.

By understanding the basics of Super drive chains, designers can select the best type for a given application, enabling it to operate for long periods with minimum downtime.

The task of selection is simplified by the graduated performance of products in the Super chain series.

The process begins with RS80th series.

This is the standard chain in the series, but even this chain is differentiated from the competition by incorporating a patent design ring coining process to the connecting link, thus increasing kilowatt rating by 25%.

There are then four main categories of chain beyond the standard RS80 series.

RS-HT Series chains offer greater ultimate tensile strength (19% higher) than Tsubaki's ANSI standard roller chains as a result of using through hardened pins and link plates of the next larger chain size, plus seamless rollers.

These chains also have a 9% higher allowable load capacity, making them entirely suited to applications on such equipment as motor graders, small agricultural vehicles, vertical parking towers and skid steer loaders.

Super Series chains with link plates of a special design and pitch holes that are critically formed (ball drifted) to improve their allowable load by 32%).

The pins of this chain are through hardened for greater shock load resistance and seamless rollers are employed.

Super-H Series chains with link plates have a thickness that is the same as that of the next larger size of Super Series chain, and pins that are quad riveted and through hardened.

As a result, the chains have greater ultimate tensile strength and allowable load than Super Series Chains.

The Ultra Super Series in field tests has demonstrated greater ultimate tensile strength and allowable load than any other roller chain manufactured.

As the allowable load is 62% higher than ANSI RS standard roller chain, using Ultra Super Series allows selection of a chain of up to two sizes smaller than the suitable standard chain.

Ultra Super Series is excellent for applications where heavy shock loads or space limitations pose problems, such as drilling or mining applications.

The choice of what type of Super chain to use generally depends on the prevailing application conditions and the problems being encountered.

However, for general guidance, where problems of pin breakage resulting from and shock loads range are encountered, then RS-HT series chains should be used.

Where the problem is fatigue breakage of link plates, generally poor transmission performance, or space limitation Super series, Super H series or Ultra Super Series chains are the best choice.

An additional benefit of employing these chains is that the next sizes smaller chain, or one that is even two sizes smaller, can often be used.

Further developments will be made to this chain series over the coming 12 months so as to offer customers an even greater scope for application improvement.