What is indexer

In a conveyor , usually in the paint shop a hinge is mounted at the top of chain for hanging purpose at top its mostly looks like a hook in a weighing machine but the major difference between the two is in weighing machine hooks is just for the purpose of the hanging whereas indexer can be served to rotate the object along the x-axis. In indexer the objects are holds between the two washers mounted on a rod , the road is so mounted that it can rotate by the bearings mechanism inserted inside a bush