Keeping polycord on track

[Joe Schornak]

We had a similar issue until yesterday. As the ball reached the end of our intake track, it would push the polycord out of its groove. We determined that this was happening because the curvature of the ball was pushing the cord to one side or the other, which caused it to hit the edge of a groove at an angle when the ball reached the inner roller and pull out of place. Judging from your picture, it looks like the middle loop is being significantly pulled to one side, which may be one of the causes of this issue.

Somewhat counterintuitively, loosening the troublesome loop relieved the problem. We ended up completely removing it in the end, since the intake worked just as well with two cords rather than three, but I do not know how this would affect your design.

Also, the process of pulling the ball against an angled rail could be pushing your cord. In my experience, the balls have significant grip against many surfaces, so you could try putting a slicker surface where the ball would contact. We have used teflon tape in similar applications with positive results.

Let us know if you have any further issues, and have a most excellent final build week.

[45Auto]

We're using a similar pick-up system, and had the same problem. Even made our rollers the same way you did. The ball needs to be able to roll against your side guides.

Put some PVC "rollers" over your guide rails, like you see in the cad model below. That simple fix made ours work unbelievably well!

[MrForbes]

Originally Posted by 45Auto

Put some PVC "rollers" over your guide rails, like you see in the cad model below. That simple fix made ours work unbelievably well!

That's a neat idea!

But I think we're doing something wrong on ours, we only have one set of polycord belts, and two rollers, to do the whole harvest/lift/load-into-the-hopper thing.

[45Auto]

But I think we're doing something wrong on ours, we only have one set of polycord belts, and two rollers, to do the whole harvest/lift/load-into-the-hopper thing.

I very seriously doubt if you're doing anything "wrong" , just make sure that multiple balls don't bind up on each other as they roll against each other.

The balls generate a lot of friction when they try to roll against each other. We've had bad experiences with single-feed systems with multiple balls binding up which led to our "dual lift" design with cords on front and back where the balls don't roll against each other.

Your system probably works better than ours if it's engineered correctly!

[MrForbes]

No, we do have the problem with multiple balls being able to easily jam in the intake. It's neat to see how you solved that problem.

The main reason we don't have much stuff on our robot, is because we're lazy....we'll spend hours figuring out how to avoid making more parts!