I am sometimes asked whether you can extend the life of a leaf chain fitted to a forklift, simply by swapping or reversing ends?
How would this work? In a nutshell, following a leaf chain being measured for wear, it is removed, cleaned and inspected for continued suitability. If it is considered fit for purpose, it is then refitted but with the ends reversed – the end previously fitted to the top anchor bolt will now be fitted to the bottom bolt and vice versa, rather like top to toe-ing in a bed. In theory, this would allow you to extend the service life of the leaf chain.
Does this actually work?
Leaf chain wear is a direct result of load, together with the articulating movement, as the leaf chain rotates over the chain pulley. If there is no load and no articulating movement then the leaf chain will not wear. This means that the only portion of a leaf chain that can wear is the one that moves over the chain pulley.
In set-ups where there is little movement, or where there are long lengths of spare chain, there could be long sections of the leaf chain that do not touch the pulley and are therefore unaffected by wear. On the other hand, in some applications, almost all of the leaf chain rotates over the pulley.
The traditional view is that reversing a chain is not the best practice or strategy – and although I would generally tend to agree with that advice, here at FB Chain we would prefer to consider each individual situation on its own merit as not all applications are the same. Leaf chain set-ups can vary considerably and there could be a circumstance in which this practice would be acceptable as a one-off solution.
You can increase the risk of failure when you reverse a leaf chain
However, there are several reasons why it's less than ideal.
Cracked links as a result of fatigue failures can cause catastrophic damage and are notoriously difficult to spot. These fatigue failures are caused by cyclic loading which happens every time the forklift moves a load. In certain applications – for example, when a forklift travels long distances over a rippled floor – the leaf chain can see many thousands of micro loads – increasing the risk of fatigue failures.
If you have a good chain wear inspection regime in place, then practice dictates that the chain is replaced when it is beyond the measured limits of wear. This will happen before the chain reaches a maximum amount of cyclic loads. (Use a chain wear gauge to measure how worn the chain is). By extending the usage of the leaf chain by swapping ends, without careful consideration, you significantly increase the likelihood of fatigue failures.
Would it reduce costs?
The cost of the technician time to do the work is often greater than the cost of a replacement leaf chain. So to make this procedure viable the replacement chain cost will need to be relatively high. The smaller, high volume, popular leaf chains are normally sold at low pricing levels that would not usually make this worthwhile. For larger pitch sizes and longer chain lengths however, this technique could, on paper at least, reduce costs.
In fact, the viability of this technique is dependent on chain length. If by reversing the chain any part of any link that previously rotated over the pulley will do so once re-fitted, but in reverse, then the process should be considered a waste of effort.
Given the relative ease with which you can replace a leaf chain and the safety and cost implications of chain failure, it is usually easier, quicker and most certainly safer to replace an existing worn chain than to swap its ends.
For advice on this subject, leaf chain wear, measurement or anything to do with leaf chain, please contact us here at FB Chain, where one of our experts will be more than happy to advise you.