Forklift chains are an often overlooked part of a forklift. The assumption is sometimes made that since they are a steel part and that the forklift mast is still lifting and lowering, the chains must be safe. This attitude can be far from the truth. Chains on forklifts are under constant strain and pressure which leads to wear and breakage. If a chain on a forklift breaks, employees can be hurt. A broken chain can also cause other chains to be compromised and need replacing.
OSHA requires daily inspection of each forklift you operate, but the specifics on this are not clear. In order to prevent chain breakage, there are regular maintenance and inspections that will help make your forklift safer. Lift chains should be inspected and lubricated after every 250 hours of truck operation. There are several chain conditions that you should look for.
First is wear on the chains. Chains can stretch due to changes in material wear of the pin OD and inside the plate ID. Measure the chain when the machine is under a load and slack is not present. When the chains have stretched or elongated 3%, they should be replaced. Elongation of 3% results in a 15% reduction in strength. Always measure a segment of chain that has contact with a sheave. Do not repair a chain by cutting and splicing a piece. If part of a chain is worn, replace all the chains on the forklift.
Cracked plates are another indicator that the chains need to be replaced. If cracked plates are present, replace all the chains on the machine. Cracks indicate metal fatigue caused by repeat heavy loads. If some of the plates are cracked, many of the other plates could be on the verge of cracking which makes chain failure likely.
Chains that are operating with little lubrication and regular heavy loads have tremendous friction between pins and bushing in the chain. Sometimes the torque in the joint can turn the pins in the outside plates or the pins can work their way out of the chain, which will cause chain failure. You should not try to drive the pins back into the chain to repair the problem.
Rust and corrosion contribute to chain failure and reduced strength. Chains need to be protected from corrosion. Oil chains regularly to help keep them from corroding. Under some conditions it may be necessary to increase the frequency of maintenance and oiling. Corroded chains may also have cracked plates and pin problems. If the chains are heavily corroded, they should be removed from the forklift for thorough inspection and possible replacement.
If there is a wear pattern present on the pin heads and outside plates, misalignment is indicated. This condition damages chain and sheaves and increases internal friction in the system.
Make sure that your inspection of the chains includes an examination of the chain anchors and the sheaves. Most daily inspection lists include a mast inspection, which includes the chains, so if your operators are doing those inspections, they should be aware of and able to notify their managers of potential safety hazards.
The condition of the chains affects the safety of the operator, vehicle and cargo. It is crucial to inspect and maintain the condition of the forklift chains to keep your forklift in good working order.