Balls getting stuck in hopper
 

We are having trouble with ball getting stuck at the bottom of our hopper.
Does anybody have any ideas?

Re: Balls getting stuck in hopper
 

How are we going to know what your hopper looks like. You shoul.d at least post a picture.

Re: Balls getting stuck in hopper
 

try using an agitator to move the balls at the floor of the hopper.

Re: Balls getting stuck in hopper
 

I'm guessing that you are using a gravity feed hopper. one thing that we have found is that no matter how you plan for it, the balls will get stuck. i suggest a agitator mechanism that keeps the balls moving and will not let them get stuck. something as simple as a turning lazy susan that allows the balls to continue to move around.

Re: Balls getting stuck in hopper
 

I have to agree. We can't read minds, especially through computers. if you can't post a picture you should at least tell us what kind of hopper you have.How did your team design this?

Re: Balls getting stuck in hopper
 

my team is having the same problem you are but we are or were using a funnel type loader but then went to a square track with rounded edges. :yikes:

Re: Balls getting stuck in hopper
 

Having played with models of several approaches, the one that works best is to use a single-ball channel of some kind: either ramps or a spiral. In Top Gun the balls never have a chance to jam. During their short stay in the robot the balls are always lined up on tracks, either dropping via gravity or rising on pressure belts. If you don't ever let balls get side-by-side, you won't ever have to worry about them jamming up.

In bulk material operations, stirring mechanisms are sometimes used to prevent granular stuff from plugging up chutes and outlets. We didn't go this route so I don't have anything to add from experience, but it seems to me that a short "stir stick" attached to the F-P motor with its low-speed, high-torque transmission intact might be just the thing. If you are using pneumatics, a short piston pushing upwards on a "thing" might jostle the balls when they jam.

Re: Balls getting stuck in hopper
 

i would sugest a agitator of some sort sorta like an electirc paint bALL hoper

Re: Balls getting stuck in hopper
 

Launching jammed balls = (possibly) robot spewing confetti all over the arena.

You should be careful about this. If the ball ends up jamming and they jam inside then launch them with, say, a pitching mech then this may happen. Most likely your team will be flagged for it and run the risk of being disqualified. That is, of course, bad and will mean that in the end you designed and built for six full weeks, sacrificing sleep completely to get this project done, and it fails.

YOU HAVE BEEN WARNED!!!!!!!!!

Re: Balls getting stuck in hopper
 

And if an Agitator would work, but you don't have room for a motor and arm, you could add a "shake and shimmy" button. Drive the drive forward and backward a few times quickly and shake the whole robot.

It goes without saying... loktite would be a good idea if this is the route you take.

But - please post a picture.

Re: Balls getting stuck in hopper
 

maybe this is illegal... but what if you mount your compressor to the hopper? even if you aren't running a complete pneumatics system... it would surely keep the hopper vibrating :)

Re: Balls getting stuck in hopper
 

I am not sure either, but I am sure that you could at least mount the copmressor next to the hopper. I am sure that the hopper won't virbrate as much, but maybe just enough. Enough is dependant on your design. Its all about design. don't tell me it's strategy because that is very dependable on design.

Re: Balls getting stuck in hopper
 

This is the belt fed, magazine, revolver debate. Our team is going with the revolver. We have a basket with a paint stirrer type paddle that sweeps the balls to a hole in the bottom of a basket. they then drop into the firing mech. By it's design the balls get jostled. Feeding the balls is proving a little challenging unless a team is going for a all at once 10 shot autonomous strategy.

Re: Balls getting stuck in hopper
 

Good call to jostle the balls. If they were just left to allow gravity to do all the work you may not be loading at all. THAT WOULD CERTAINLY SUCK.

Re: Balls getting stuck in hopper
 

If your team uses a gravity-based hopper the way ours does, I would recommend a spiral, since it's completely passive and you won't have to add any more motor weight. If you find that a spiral alone doesn't help, though, then you might want to add an agitator. I have to say I like the idea of mounting the compressor on the hopper - and I went and searched through the rules (starting on page 20 of The Robot), which said nothing about mounting pneumatics except that you have to use the preexisting threads. Since I assume you don't plan to drill any new holes in your compressor, that would be a great idea.

Re: Balls getting stuck in hopper
 

We can't really give a difinitive answer unless we know what kind of hopper is being used.

Our team is using a hopper that is just meant to hold a mass of balls, and we did have an issue of them getting stuck in there. If you keep the balls moving around some, then they aren't going to be stuck. If you are going for a different stratergy and a different hopper, look at some of the other posts to see if they apply.

Re: Balls getting stuck in hopper
 

hehe, i could give you the first idea our team had...you could shake and shake like central did a few years ago..lol, i love watching that

Re: Balls getting stuck in hopper
 

central? watching wat?

Re: Balls getting stuck in hopper
 

My suggestion is a pneumatic piston that just pokes at the balls when needed for un-stuckage. however, if you don't already have a pneumatics system on your robot, then you might want another alternative

Re: Balls getting stuck in hopper
 

We're trying a conveyor belt on one side of the hopper that travels UPWARDS. This is supposed to lift balls up out of a jam.

Re: Balls getting stuck in hopper
 

What kind of net are teams using: volleyball, badmitton, fishing?
We bought a fishing net to try. I am worried about balls sticking some.



Carolyn

Re: Balls getting stuck in hopper
 

I very much doubt that balls would end up getting stuck when you use a fishing net. The holes should be small enough so that fish would not escape through the holes, and I am pretty sure that the balls we are using are much bigger than the fish.

I have not seen a badmitten net in my life ever so I can't help there, but the nets used in volleyball should be big enough as well.

I am guessing that your team designed a funnel for your robot. the use of a net is actually a dead give away. how about letting us in on how your team designed it.

Re: Balls getting stuck in hopper
 

An agitator would be easy and cheap, but you could build differant gravity feed hopper.

Re: Balls getting stuck in hopper
 

Really it depends but I would think to pull the mechanism used for pulling the balls in to the shooter more.

Re: Balls getting stuck in hopper
 

Simple fix. Go back to week 1, and decide not to use a hopper. ;)

Re: Balls getting stuck in hopper
 

If your using a rotating wheel shooter try adding weight on the rim of the wheels. This should make the wheel unbalanced and shake similar to cell phone vibrators. The shaking shouldn't disrupt your shooter , but try it and see.

Re: Balls getting stuck in hopper
 

================================================== ======
Well, we had a rim with the wide end of the net and if came to a narrow end with a rim. However, balls still got stuck. We looked at putting in a funnel towards the bottom, but still had 2 or 3 ball combinations that stuck. We had the fishing net taunt and they still stuck. We tried a turning thing that would sometimes unstick them but even that was unreliable.

So as the person said above we went back to some beginning ideas and are mocking up now. Maybe hopper plus tracking.

Hope this helps. I am still interested how teams with the netting are working and not sticking. :confused:

Carolyn

Re: Balls getting stuck in hopper
 

I am not sure what you mean, but I am guessing that when you say "narrow end" you mean a slim tube big enough for one ball to fit through. This will give the balls less room to pass and create friction. As a ball spins downward due to slope it rubs of against the ones behind it. If the balls don't end up shredding before coming out they most likely won't come out at all. How I know all this if this is my first year in FIRST? One of the professors from the California State University in Northridge had warned us against this.

as for the hoppe+tracking: well, that would be one annoying challenge. Could be used for autonimous mode, programming this to happen when the servos connected to the cam reack this position and react accordingly.

I still wonder how balls actually manage to get stuck on fishing net.

Re: Balls getting stuck in hopper
 

When the previous posters said "tracking" I believe they meant a mechanical track that the balls would roll on. Like the track for grain in a barn, not tracking as with the camera.

Also, I dont think that a ball rolling down something like a PVC pipe (or similar) will be be shredded. It will come out without shredding, as all of our tests have shown. As long as there are no overly sharp edges (such as jagged aluminum), there is no reason why a ball with little pressure on it will shred.

Re: Balls getting stuck in hopper
 

^ lover and worshipper of the three- eyed demon who calls himself Hiei

Quote:

Originally Posted by chinckley ================================================== ====== Well, we had a rim with the wide end of the net and if came to a narrow end with a rim. However, balls still got stuck. We looked at putting in a funnel towards the bottom, but still had 2 or 3 ball combinations that stuck. We had the fishing net taunt and they still stuck. We tried a turning thing that would sometimes unstick them but even that was unreliable. So as the person said above we went back to some beginning ideas and are mocking up now. Maybe hopper plus tracking. Hope this helps. I am still interested how teams with the netting are working and not sticking. :confused: Carolyn

A fishing net? Quite intuitive; it's difficult to imagine balls getting stuck in that. However, to rectify your dilemma, you could use dual pneumatic pistons on the smaller rim that constantly move it around one or two inches along the vertical axes. This would jar any caught balls; you would, however, have to add an accordion-like piece below the funnel.

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Re: Balls getting stuck in hopper
 

[quote] This would jar any caught balls; you would, however, have to add an accordion-like piece below the funnel.[quote]


or you could just have it on a system that allows just the outside of the hopper to spin. this would work very well for a vertical hopper