Designing a "belt + roller" conveyor for balls

[Scott Kozutsky]

Originally Posted by Jared Russell

When 341 made extensive use of polyurethane flat belting in 2012 (and 2013), we used exclusively 1.25" OD, 1.12" ID aluminum round tubing from Online Metals for our rollers. 10 seconds on the lathe (or a minute with a deburring tool) and it is a great fit for a hub or 1.125" OD bearing.

In 2014 we used the polycarb tube for our rollers and it definitely suffered from a lack of rigidity. The aluminum upgrade is definitely something I would recommend. Our tubes were around 2ft+ long.

[Monochron]

Thanks for all the great feedback everyone, the team working on the beltway for our shooter got a lot of use out of the resources you guys provided.

We currently have the plates that make up the shooter assembly CADed and will sending them out for manufacturing on Monday. If people wouldn't mind giving the design and especially the drawing a look over we would really appreciate it.

Shooter Plate
Shooter Plate Drawing

Feedback I would particularly like include:

• We're going with a 1/4" thick plate, is that appropriate for this application?
• Is the pocketing too agresive? ie. are 1/4" aluminum struts strong enough?
• Is the Drawing too hectic? It looks like I have a lot of dimentions crammed in there...
• Also any overal design comments you have are welcome

[jman4747]

Has anyone else used hollow core round belt with the barbed connector? Example: http://www.mcmaster.com/#6567k57/=109btha (belt) http://www.mcmaster.com/#6567k22/=109bt5d (connector)

[GeeTwo]

Originally Posted by jman4747

Has anyone else used hollow core round belt with the barbed connector? Example: http://www.mcmaster.com/#6567k57/=109btha (belt) http://www.mcmaster.com/#6567k22/=109bt5d (connector)

We used this type of belt for our rookie 2012 Rebound Rumble robot to pick the basketballs off the floor and raise them to the cup which would lift them to the shooter. It was probably the most reliable system on the robot. I was not as involved that year, so I don't know why, but the belt was taped together rather than just held with the barbed connector. I suspect that it was because we were running it around about 1" diameter rollers (larger is recommended).

[jman4747]

Originally Posted by GeeTwo

We used this type of belt for our rookie 2012 Rebound Rumble robot to pick the basketballs off the floor and raise them to the cup which would lift them to the shooter. It was probably the most reliable system on the robot. I was not as involved that year, so I don't know why, but the belt was taped together rather than just held with the barbed connector. I suspect that it was because we were running it around about 1" diameter rollers (larger is recommended).

That's my exact situation. Last time we used them was on our 2012 rookie bot and they were also on < 2" diameter rollers and taped. I was wondering if anyone else had because like you I wasn't very involved with the lift and want to make sure we didn't just get lucky with it.

[Chris is me]

Originally Posted by jman4747

That's my exact situation. Last time we used them was on our 2012 rookie bot and they were also on < 2" diameter rollers and taped. I was wondering if anyone else had because like you I wasn't very involved with the lift and want to make sure we didn't just get lucky with it.

Back in high school (seven years ago!!! ) my team used these in 2009 for a ball conveyor, just using the barbed connectors to join them, around ~2" rollers. Worked well, I don't think they ever pulled themselves apart. The belts may have stretched a bit over time since they are hollow and relatively thin, so have some extra barbs so you can shorten longer runs over time. Welded poly-cord is probably more robust but this was good enough for 2009.

I personally prefer the orange flat stuff since it's a bit tackier and has nice self-centering properties.

[Ari423]

Originally Posted by GeeTwo

We used this type of belt for our rookie 2012 Rebound Rumble robot to pick the basketballs off the floor and raise them to the cup which would lift them to the shooter. It was probably the most reliable system on the robot. I was not as involved that year, so I don't know why, but the belt was taped together rather than just held with the barbed connector. I suspect that it was because we were running it around about 1" diameter rollers (larger is recommended).

My team also used them for our intake in 2012 and we did use the barbs. When we first cut the urethrane, the barbed connectors constantly popped out. After a few days of sitting and stretching they would be fine until the urethrane would stretch too much, we would have to re-cut it, and the process would start over again. Also, the barbed connectors are a pain to take out. That being said, they worked pretty well for our intake, and I would use them again if the need arises.

[mott]

Originally Posted by Scott Kozutsky

In 2014 we used the polycarb tube for our rollers and it definitely suffered from a lack of rigidity. The aluminum upgrade is definitely something I would recommend. Our tubes were around 2ft+ long.

Other than the added complexity of machining the bore of the tube ends, would it be worth using the 1.25" OD polycarb tubing with the 1" ID and then machining the bore of the tube ends to accept the 1.125" bearing and hub? Besides being significantly stiffer, this would also allow you to intentionally undersize the bore to get the amount of "press fit" you might want for the inserts.