John King Chains

21.9 Chain joint seizure

Chain joint seizure

Chain joints are susceptible to seizure if the bearing surfaces become severely corroded or galled or if the clearances between the chain parts become backed with material that tends to harden, in moderate cases chain and sprocket interaction will cause the joint to break. In the case of severe seizure the restriction in normal articulation can cause a torsional pin break or sidebar pitch hole tear.
A protective coating may be desirable to prevent rust build up and care should be taken in start up during periods of sub zero temperature. Occasional operation during periods of non production is very beneficial in reducing chances of binding. In severe cases corrosion resistant pins and or bushings may be preferred.
In some cases and generally for larger pitch chains, King have introduced grease lubrication through the bearing pin, a typical example is cement clinker pan conveyors. Lubrication is introduced into the joints of the chain through a grease way thus protecting the bearing grease and preventing the ingress of foreign materials.
Chain joints can also freeze as a result of galling if chains are operated beyond design capabilities.