Safety

Limiting stretch in v-belts and chains

Both chain and v-belts have one ongoing issue – stretch. As they stretch, they become less efficient. V-belts begin to slip and chains begin to ratchet or bunch up on themselves.

If not maintained, retensioned or replaced, they will rapidly fail and decrease in efficiency.

With v-belts only capable of around 93-94 per cent efficiency at best, stretching quickly reduces that further. As a consequence, power bills increase along with associated emissions from the creation of that power and the cost in labour, and lost production. 

With monitory considerations now being discussed in relation to carbon emissions, this inefficient use of power will cost quarry operators even more, not to mention the impact on the environment. 

To keep drive efficiency at its maximum levels, stretch needs to be maintained, lessened or eliminated altogether. 
When considering limiting stretch in v-belts, the quality of the v-belt will be a major factor. Higher quality manufacturers/
products have:
? Better bonding agents to set the tensile cords in the body of the belt 
? More stretch-resistant cord materials
? Rubber batched, specifically to reduce resistance to flexing (bending) around the pulleys 
? Tension recommendations that will ensure the belts operate at their peak efficiencies 

All those things influence v-belt stretch and, of course, the efficiency of the drive over its life. However, they still stretch, as do chain drives. To eliminate stretch in a drive system, there is only one drive option and that is a synchronous belt drive.

Synchronous drives will maintain their 98-99 per cent efficiency over their lives. They also guarantee specific output speeds, which means more control over the application they power. This is especially important for pumps and air handling units that are severely impacted by their running speeds.

Also, today’s generation of synchronous belts are extremely powerful and will transmit power in very compact spaces.

By giving consideration to the products used in rotary power transmission, quarry operators can lessen their maintenance, minimise v-belt stretch or eliminate stretch in v-belts and chain drives altogether. 

Rob Taranto is the sales and marketing manager – industrial replacement, for Gates Australia.

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