Maintenance Detective: Articulated Conveyors

Suppose you look at weekly passdowns, and one of your plastic articulated conveyors has broken the chain multiple times in the last week.

You have lots of these conveyors, but this one is breaking and getting repaired repeatedly. They're all about the same age. This one isn't all that different from the others.

It does start and stop under load, but they all do.

You go look at it and everything you can see while it's running seems fine. No jumping or bad mechanical components. It's operating smoothly.

What else should you check? Are there any common plays that could make it stop breaking?

Answer:

With articulated conveyors, like the style in the photo, there is a common weak point that is frequently missed in troubleshooting: the drive sprockets.

A little-known fact: more drive sprockets installed on this type of conveyor directly increases the load bearing capability of the conveyor because the drive sprocket teeth are the smallest contact point through which drive force is transmitted. Which means it's the highest stress point in the system.

That's where failure will start.

There are a number of ways you can have a problem. 

If someone installed a new drive sprocket with a worn one, the new one may be doing all the driving, which could break the conveyor. 

If a keyway fell out, then you're driving with less drive sprockets, which will break the conveyor.

If the conveyor is periodically breaking and just always has, you can frequently add drive sprockets to make it stop breaking.

It's important to realize that you cannot install enough drive sprockets on one of these conveyors to transfer the weak point anywhere else, the drive sprocket will be the high stress point where cracking will originate.  But more sprockets  directly increases strength.  If you're doing battle with one of these that cracks and breaks repetitively, add drive sprockets. Make sure they're all the same.  Make sure they are all carrying load.