Conveyer belt "wander" auto-correction?

IIRC, it depends on the belt & roller material, also on whether the roller is powered, or an idler.

Again, IIRC, it's a convex profile for elastic belts (eg; leather, neoprene), & concave for other materials (eg; chain, fibre-reinforced).

On Wed, 25 Apr 2007 07:41:57 -0700, DaveC Gave us:

Have a roller tube made that is concave in shape. That tube goes at one end, and the adjustment end is the other. Then, the taughtness of the belt is what keeps it in the center of the "fall zone" of the concave roller.

On Wed, 25 Apr 2007 15:17:12 GMT, Palindrome Gave us:

Or, just the opposite by placing a "dip" in the center, the belts edges are kept within the ends of the roller.

Some cases concave works, and some cases convex works. That roller goes at one end, and the adjusting roller goes at the other. It may or may not already have an arced (convex) face. The overall taughtness of the belt is also a factor.

On Wed, 25 Apr 2007 08:42:04 -0700, DaveC Gave us:

It is an arc and it is less than a couple degrees across the entire face.

On Mon, 30 Apr 2007 16:51:11 +1000, Lionel Gave us:

Go away, troll. Your grasp of mechanical engineering is on par with your level of maturity in your behavior in usenet, and you have proven that to be nil.

On Mon, 30 Apr 2007 16:46:51 +1000, Lionel Gave us:

Neither is a solution.

There are two different mechanisms that can be at work. One is the "inclined plane". The other is "longitudinal displacement", caused by part of the belt having a longer path (ie over the larger roller diameter(s)).

On Mon, 30 Apr 2007 09:31:44 GMT, Palindrome Gave us:

There is one more. The belt flexes, and then rebounds from the flexure. The taughtness of the belt in its center on the domed set up creates a line of tension down the length of the conveyor. The perpendicularity of the other end (the adjustment face/roller) with respect to that line of tension, is what keeps things centered. The less taught sides are where the entire "system" looks for a symmetry in the forces that would shove the belt end off the edge of a roller.

The goods being placed on the belt also become a factor.

So, the tension is really one of the most important factors for making the domed roller have enough "affect" to exert continuous control.

You could put small rollers on the arms that do this. You really don't want to add a drag to the one side. The added drag will work against the effect of the arm. This method requires that the belt in question be somewhat springy. I don't think the OP stated how springy it is.

Great explanation and suggestion. Thanks.

Which brings up a question: does a concave or convex roller work best at the drive (no adjustment) or idler (adjustment) end? Or would it matter where either is placed?

Thanks,

OP here...

Crowned looks like the best option. Splitting the roller requires additional support and bearings. We regularly have rollers reground by a specialty service, and I will ask them about doing this to the (rubber) drive and idler rollers. (Would having both rollers crowned be better? Or is one sufficient?)

Second, as someone suggested here, will consider the inclined rollers added in the belt's path at the extreme ends of the belt's width to encourage centering.

FYI, it's a sheet-fed operation, not continuous web printing (and, specifically, this machine is a sheet-fed coater). Light weight product on the belt (less than a few pounds over the entire length of the belt at low speed). Belt is mesh carbon fiber. Seems somewhat springy, overall, but the material, per se, isn't flexible.

Thanks to all for your suggestions.