Steel Chains for Power Transmission

Kitmondo 06 May 2014

This article first appeared in Practical Engineering 1940 Vol1 No2. All of  the information contained within this article is relevant as of 1940. This particular article looks at how modern technological developments aid efficiencies within the Engineering field.

The field of application for steel transmission chain is without doubt unlimited, as indicated by their manifold uses for main, secondary and auxiliary drives on all types of machinery. The initial achievement of the transmission chain was, of course, to give the positiveness and compactness of gears without vibration or noise and the smoothness and elasticity of belts without slip.

A test carried out at the National Physical Laboratory, Teddington, recently, proved that a Renold chain drive gave a sustained output of between 98.4 and 98.9 per cent, of the power transmitted. This elimination of power loss was sufficient in itself to engage the attention of engineers, but over 50 years' practice has revealed many other desirable features of chain drives. In a nutshell, the advantage of chain drives is that they form the most versatile transmission medium.

Short Centre Drive

If the shaft centres arc definitely fixed, jockeys of the hand or automatic adjustment type can be used. Installation is a comparatively simple matter; centre distances present no problems since it is not necessary to work to a definite distance as with belts. Short centre chain drives save space, enable convenient mounting of the motor, and offer 100 per cent, positive drive with sufficient flexibility to start a considerable load without shock or slip.

Detachability of chains for renewal or to free the shafts is quick and easy. Maintenance is negligible; demanding only lubrication with infrequent adjustment. Atmospheric conditions do not affect the efficiency of chain drives, which, if provided with correct lubrication, have an exceptionally long normal life.

Freedom From Slip

Many drives are supplied by the Renold and Coventry Chain Company, Ltd. This Company also manufactures steel chains for conveyors and elevators, chain clutches, chain couplings and Renold-Hardy couplings, chain speed transformers, counterweight and rack sets, and chain “push-pull" remote control gear.

By way of example, a Renold chain drive was installed from oil engine to dynamo and circulating water pump at a waterworks; this being one of a series of chain drives which replaced the original transmission because of their greater efficiency and freedom from slip. Also, it was found that by using chain drives, their high efficiency enabled the running of a 17 kw. generator to be dispensed with, which was previously required at peak load during winter with the original transmission. These drives always run for a minimum period of 40 days and nights (960 hours) continuously and occasionally for 1,500 hours without stop. No trouble has been experienced, and a recent inspection revealed that wear was negligible.

Another example would be a tappet shaft drive from the crankshaft on a cotton loom. This is a particularly interesting application of chain drive as it is the usual practice to employ machine-moulded spur gears. With the chain drive the load is distributed over an even number of teeth, that means much less vibration and smoother torque—all making for the production of a better quality of cloth.