Roller Intake Compression

Hey Guys!
I am having trouble getting cubes up my tray. Im using a bot that has a 2-bar with rollers on the ends of them and a folding tray for them to go into. Right now, however, the bot can only hold 4 cubes at a time before the intake loses the compression to push up another one.
Any tips?20190910_104224

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maybe look into larger paddles on the rollers and a longer track.

Also what motor cartridge are you running. A lot of people have struggled with too much friction to use 600rmp cartridges.

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Right now, they are the stock motor cartridges (200 rpm I think)

just now seeing that photo, your paddles are very inconsistent, try making the spacing on them very even and closer together.

Maybe try not cantilevering your intake sprockets. Supporting on both sides will reduce friction when the cube pushes them apart. 200 should be fine, it’s what most teams are using.

I know that I am using the 100 rpm rollers on my intake. That seems to help a little.

Do your rollers have locks? If not you should definitely make some.

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This likely can be solved via a more shallower tray where you have a better advantage via slope, or it can be solved by making your arms stiffer and have less flex by by doing box channels as stated in the 448X documentary.

Use more flaps, as many as you can. I have 1 flap every 3 or 4 chain links. Also your rubber banding isn’t the best for compression, they need to be more sideways for more force.

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Like @Zach3324A said, really the best solution is to use a lock on your intake. They’re somewhat tricky to make, but work like a charm.

Since your problem is compression, 200 rpm gear cartridges are perfectly suited.

Size a spatial distribution of paddles should also not make much of a difference. If your intake has enough compression, it’ll work.

Good luck!


I’m not sure what the exact specifications of your robot are, but the first stage would appear to hold about 4 cubes (assuming it’s full length angle). This means that the intake starts to struggle at the connection point between the first and second stage. The gap is pretty large and uneven. The problem very well might also be the intake in addition to this, but I’d fix both problems while you’re at it.

Lock really isn’t necessary, our robot can do 10+ cubes fine without a lock. What really matters is how your rollers rotate. Some rotate similar to the 448X RI3D, but others (like 1961z) have the intake rotate around their 2-bar itself. This allows them to overlap their intake into the tray to allow good compression. Outtaking is also not an issue as their tray can pull apart their intake, meaning that they can add any more amount of compression and outtaking will not be impacted.

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While your roller rotation works great, they can’t really implement theirs in the same way you did, since their rollers flip out. The way their flip out is set up, really the only solution is a lock.

Outtaking is also not an issue, even with a lock. The tray has plenty of force to twist the lift arms slightly, pushing the rollers out of the way.

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How do you suggest that the intake lock needs to be made so it gives the compression needed.

My team used a rotating C-channel on the outside arm of the 2-bar, but goofy’s lock works fine too.

Could you post a picture? And do you know how exactly Goofy got their lock to work so smoothly without it getting caught?

As @Freshscott said, you should extend the track and make it longer. Below is a picture of my team’s robot from Toss Up where we had a long track to pick up the bucky balls. Hope this helps.

I agree, don’t use 600RPM motors. 200RPM high speed work best for me. But the speed of the intake should not be affecting how much friction is being put on the cubes from the rollers. I would suggest adding a lot more flaps, and tightening the bands even more. I would guess you have already tried adding tons more bands only to find it still doesn’t work. I would assume this is because of the stability of the 2 bar arms. add more support to the arms, even do something like 1961Z’s reveal on YouTube where their tray will lean foreword a bit so the extra stabilization on the 2 bar lift arms can move freely without hitting the back of the tray. This should help the arms to not give or slightly separate, which is the main problem. also, like @2775Josh said, add a locking mechanism to your arms and it will greatly increase their stability. Hope this helps!

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I would suggest from experience and seeing that your rubber bands don’t seem to be far enough out. For example if your rubber bands are close to a degree of 90 and you’re trying to pull it the other way which is 90 degrees around it will not do the job because the rubber band is pulling back. You should find a way to extend the rubber band out just a little or more and will find a big difference. @9364Y Adding to many flaps can be bad. It doesn’t matter if you had every whole with flaps not until they fix the rubber band problem will that start to take effect. But I do suggest flaps just don’t go way to far with it. You also would want to be fast so yea use the high speed because it seems your intake at a angle will be able to pull them in good and faster.

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