When is 1 ton greater than 1 ton?

When is 1 ton greater than 1 ton?

We’ve all used chain motors and we’ve all suspended the maximum 1 ton rated loads. But do we ever really think about what happens between the 2 hooks?

If you are an operator, you have probably been trained to understand forces. A load in motion exerts greater forces than a static or non-moving load. Load position and hoisting speed affect the magnitude of these forces, which can be measured in excess of 200%. This alone should be sufficient to make us more cautious when using overhead lifting equipment.

But what if I told you the forces mentioned above are overshadowed by the force we see in the inter-link of our load chain?  The contact area where 2 links touch is only .006 inch. With a one ton static load on the hoist, pressure between links can be as high as 500,000 pounds per square inch. If this is not enough to open your eyes, think of a stage using (12) 1 ton hoists each performing a 40 foot lift. We have 6500 working links, each one subjected to 1/2 million PSI. Moving the load increases this pressure. Imagine the amount of friction and resulting heat.

Is lubrication on the load chain really necessary? Tell us what you think.

Dave Carmack

Dave is a Product Trainer for our CM Entertainment Division. Other credentials include being an ETCP Recognized Trainer & IATSE TTF Recommended Trainer.

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One Reply to “When is 1 ton greater than 1 ton?”

  1. Well it depends on how often you want to change out your Chain, Lift wheel, Hook block sheave, ect… I am not sure of the exact numbers that you state, but I have seen where lubrication of the load chain does extend the life of the load chain.

    Case in point.

    I had a customer who installed (self installation) a new CM loadstar hoist. No worries installed on a mono-rail beam. The hoist was used to pick up bags of materiel. The weight on the bags was mostly half to three-quarters of the capacity of the hoist. But the customer was a food grade plant and it was decided since the lube sent with the hoist for its chain was not food grade they could not use it. Note: the customer did not call us at this time. The chain wore out in less than a year. The customer was unhappy about the chain wear and tried to say it was warranty work. When the lack of lubrication was pointed out we were informed that it was due to the lube not being food grade. Well after the new chain was installed we used a food grade light machinery oil on it. And have been cleaning and relubricating the load chain every quarter. This load chain has been in operation for two plus year now with little signs of wear.

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