Conveyor Belt

[jeetshah]

What type of belts would be good for a conveyor system

[Otaku]

I'm sure there's a number of ways you could do it, but the easiest to do (probably) would be just "standard" treadmill/conveyer belt material... I don't know what it's called but it's almost always the same kinda stuff -- this black cloth/hard rubber material covered in tiny divots for traction.

This kinda stuff:

http://www.made-in-china.com/image/2...-Polishing.jpg


You could always get more complex and do a series of thinner belts, use cloth, etc, but your best bet's probably just that "standard" material imo. Seemed to work pretty well on our '06 bot.

[jmarsh24]

Use the surgical tubing that came with the robotics kit! Its extremely light and effective...

[Lowfategg]

I have also heard of teams using round belting.

[sdcantrell56]

Look up round urethane belting on mcmaster. This is what we are planning to use. It's nice because you can make any length belt you choose and it's pretty cheap.

[jmarsh24]

They question is.... is it a little over kill? And how much weight will it cost? The belts from conveyor belts from mc master in my concern would be too "industrial" for our needs. Any have any other ideas for something like surgical tubing, but better friction?

[MrForbes]

We've been looking at pictures and descriptions of a lot of 2006 robots, and there seem to be several ways to move balls without using a conventional conveyor system. Archimedes was onto something....

[Kevin Sevcik]

Originally Posted by Otaku

I'm sure there's a number of ways you could do it, but the easiest to do (probably) would be just "standard" treadmill/conveyer belt material... I don't know what it's called but it's almost always the same kinda stuff -- this black cloth/hard rubber material covered in tiny divots for traction.

Actual conveyor belting is a bad idea. It's a flat belt, so it's much more difficult to get it to ride true than a round belt or V-belt or something. You'll need crowned pulleys to have reasonable odds of keeping it on, but that's dependent on how well aligned the pulleys are. If they're too far our of parallel with each other, the belt is inevitably going to walk to one side or another. They're just generally harder to get working than the round urethane belting. Which is why you see so many teams running the urethane belts.

[Richard Wallace]

Originally Posted by Kevin Sevcik

Actual conveyor belting is a bad idea. It's a flat belt, so it's much more difficult to get it to ride true than a round belt or V-belt or something. You'll need crowned pulleys to have reasonable odds of keeping it on, but that's dependent on how well aligned the pulleys are. If they're too far our of parallel with each other, the belt is inevitably going to walk to one side or another. They're just generally harder to get working than the round urethane belting. Which is why you see so many teams running the urethane belts.

My team's experience in 2006 supports what Kevin said above. We had a sponsor that donated materials for a flat belt system to elevate Poof balls to our shooter. The elevator worked well, except when it got out of alignment, lost tension, or slipped a belt. It did those things often enough to make our shooter ineffective in many matches.

I recommend using solid round conveyor belting.

[cgredalertcc]

In 06' 1741 used actual conveyor belting to pick up the poof balls and it worked wonderfully. The only problem was that it captured the balls so well one of our team members would usually have to help the field reset crew remove them. In the off season 06'-07' we modified the conveyor system to use industrial flat rubber bands and that worked just as effectively, but allowed us to cut our robot weight by nearly 10 pounds and sped up the pick up a great deal. The pickup was driven by both FP motors with the gear box. I would highly suggest a conveyor this year simply because it takes up less space than a screw type lift and it has the capability of picking up 2 balls at a time. Whereas, in other lifts you are limited to only one ball at a time. Also an interesting observation on the bands. The rollers at each end of the conveyor were made out of 3" PVC pipe with a cap on each end and rings of larger PVC glued in place to create ridges and valleys, our intent being for the bands to ride in the valleys, but they did the exact opposite. The bands tracked to the high points and stayed there quite nicely.

[=Martin=Taylor=]

Something we have noticed about the orbit balls is that they are very springy.

If you choose to use a belt, it should be set up in such a way that it applys a good deal of force on the ball to lift it.

If your belts are too springy the balls will slip when they reach the median point between the rollers.

We've been considering using a single high tension belt, like what many teams use in their treads.



This pic , from team 45's '03 bot, is what we really want to use. Does anyone know where they got it? F.N. Sheppard, Bercoflex?

F.N. Sheppard also has these really cool "profile" timing belts that could be used as scoops to lift the balls (instead of rolling them up a channel).

[colin340]

this http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100388913&marketID=93& locStoreNum=1278&categoryID=525742 works well you just need to sew in to a belt and work on make it to make it track well

pm for details

[Kevin Sevcik]

Originally Posted by cgredalertcc

Also an interesting observation on the bands. The rollers at each end of the conveyor were made out of 3" PVC pipe with a cap on each end and rings of larger PVC glued in place to create ridges and valleys, our intent being for the bands to ride in the valleys, but they did the exact opposite. The bands tracked to the high points and stayed there quite nicely.

This is exactly what flat belts do, and why they can be so problematic if you're not being extremely careful with them. Flat belts will always track to the highest point of a pulley if it's at all possible for them to do so. This means that if your pulleys aren't parallel, the belt will track to the high side of the pulley. Crowning the pulley can help with this, but not if your alignment is bad enough that a "low" side of the crown is still higher than anything else. This is also why losing tension can cause belts to ride side to side or ride up onto flanges. They're all somewhat elastic, so if there's enough stretch in them to start riding up on a flange, they'll happily do so and will soon be attempting to ride on the flange itself.

I'm not saying it's not possible to be successful with them, mind. Just that it requires a certain attention to detail.

[MrForbes]

Originally Posted by cgredalertcc

I would highly suggest a conveyor this year simply because it takes up less space than a screw type lift and it has the capability of picking up 2 balls at a time. Whereas, in other lifts you are limited to only one ball at a time.

We're planning on being able to pick up two balls at once, and feed them into a screw lift. This design details are still vaporware

The screw lift does take up a lot of room, but most of that room is used to store balls, so it's not wasted.

[mathking]

We tried to make a screw lift in 2006 and it didn't work out for us. I kind of hope we can at least get a good prototype this year because I think they look really cool.

In our final 2006 design, we used a conveyor belt from flat conveyor material that was very effective. We used pvc pipe (with many "speed holes") with end caps for the rollers. We could pick up balls really well with it, and fairly easily get two balls side by side. (Unfortunately the shooting was not so good...) That said, a preliminary hand powered prototype vertical conveyor with four strands of surgical tubing worked pretty well lifting the orbit balls up 3 feet last night. One key is having a good surface opposite the conveyor to help maintain the force on the balls. The conveyor worked well enough that the render of the robot with the conveyor is still hanging on my classroom wall.

Another thing to watch out for the conveyor mangling the balls if they stay and and get pulled back down. In 2006 we would occasionally pull the balls through a 2 cm opening between the conveyor and the chassis if the hopper was full. That would probably destroy the orbit balls.