So on our robot this year we decided to do a gravity loader pretty early on we figured out that there would be a huge nesting issue when one frisbee go’s over the other blocking it from going out the hole in the gravity loader. Since then we have made a better fitting to the frisbees loader with little space between the frisbees and the sides hoping that that would fix the problem yet we still have it. Have other teams who are doing gravity loaders / the 5 gallon bucket loaders found a good solution to the nesting problem?
We were in the exact same situation as you a few days ago. We added an angled piece of aluminum at the bottom of the hopper. This causes the bottom frisbee to slide partially into the shooter which keeps the frisbee on top from causing a jam.
Here’s a few pictures of our practice-bot’s hopper :
We found this solution to be extremely simple and effective. Before the angle piece our hopper jammed 90% of the time, since the fix it hasn’t jammed yet. 
We too had this problem in our square hopper; we were hoping the 5 gallon bucket would fix it. Though we haven’t gotten it mounted yet, I really hope it does.
How is your problem manifesting? Are the discs falling over the back or sliding out the front when you put them in? For us, we found they slid out the front as we threw the first one in and the second one slid over the back of that. From then on out we were screwed because our pusher came from the back and pushed the second disc, now angled back over the first and pushed them both bound together into the top wall of our hopper, thus not getting them out. Our hope was that a round hopper would index them so they could not angle over eachother.
A few other solutions we are still pursuing include little ‘spurs’ found in a CD thread earlier this year that spin around over the discs and separate the discs. We also considered an electric solenoid that would lock the discs in place so they didn’t fall out the front as well as some brushes to form a ‘door’. Finally, we’re upping the power on our rotary pusher from a VEX 393 to a Banebots 550 in a 64:1 that we just happened to have lying around to motor through any binding after the angle issues are worked out.
To BurkeHalderman, could you explain your angled piece a bit more? I don’t see how it works on your robot.
The angled piece works because it causes the frisbees to not be stacked straight on top of each other. When the bottom frisbee contacts the angle as it falls to the base of the hopper it slides about 1/2" through the slot to the shooter. And since the slot to our hopper is only about 1mm higher than the frisbee it eliminates any chance of the above frisbee to slide infront of it and cause a jam.
Because of the angle of the peice it only comes in contact with the bottom frisbee and still allows the next three to remain perfectly stacked.
You can see how the bottom (white) frisbee is slightly offset from the others here:
http://imgur.com/a/f3X46#7DgAFuD
I hope this explaination makes sense.
We are also doing a gravity feeder. We had the same issue and gave more space between our feeding wheels and the frisbee and also added a piece of plexiglass.
After testing it works like a charm.
We’re still working on our shooter, but seeing other peoples’ problems with jamming, we’re going for an angled hopper with a cam on a servo to allow only one disc through at a time.
We’re using a gravity feed that slides into a 5-gallon bucket and is actuated into the shooter by a pneumatic cylinder. Almost as simple as it can get. We ran into jamming the night we put our full-court shooter wheel on (lots of vibration), but tightening up the mount and adding a section of metal tap measure (as a finger to hold the disks from vibrating into the shooter) seems to have fixed the issue. We may also slope the hopper slightly towards the pneumatic actuator if needed.