Intake Compression/Motor Stall

Hey, our intake doesn’t seem to have enough compression to do above 10 cubes, but it jams and motors get stuck like there is too much compression. It isn’t the cubes getting stuck on a surface in the tray, rather just stuck in the intake itself.

Our intake is:
-Rubber tank tread + small flaps, double chained
-200rpm 18 tooth sprocket
-Has wings + mild tensioners for low friction
-4 fresh double rubber bands for compression
-Compression towers + HS axle on arm

We are hoping for an intake that can get at least 10 with no motor stallage or jamming, but it seems like compression leads to jammage. A picture is also provided below. If anyone has any advice to fix jammage while allowing more compression that would be great. Thanks!


Imagine bing concerned with getting above ten cubes. Cant be me

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We have practically the same intake, but 24T sprockets and can get approximately 5

Your intakes look to be positioned great!
However, 4 doubled bands dont seem to be enough. For me, 4 is enough for 10 with 24t sprockets, but 6 is too much, 4 is a little under.

My recommendation to you is to put more bands on your hinge system, and make sure your intakes are at the right hole amount for your 18t sprockets. For 24t, 18 holes of brace is enough.

Also, I don't know what these are, but I wouldn't recommend them


Your tray looks like it has a lot of friction too. I would add zipties to reduce friction. You take 2 zipties, cut the head off of one, thread one through the tray, and use the head as a lock. It should look something like this:


You could use 100 rpm cartridge motors for your intakes for more torque. Another solution would be to readjust the amount of compression your intakes apply on the cubes. Also spin your intakes manually to test friction, as too much friction can cause overheating and loss of torque.

Does it only jam after picking up 10 cubes? Or does it just randomly jam while picking up cubes?

How many double banded rubber bands would you recommend per hinged-intake with 24T sprockets?

The intake jams periodically, more frequent at 8+ cubes.

when we used 24T sprockets we had 2 double banded on each side and it could pick up 9 easy

I personally use 5, but it is up to the distance, and how you attach the bands

You would have to fine tune the amount of compression from the rubber bands yourself to optimize the compression for your robot. I can’t tell you how many rubber bands you should use because our intake is significantly different from yours.


is your tray 100% smooth? if there are even small, non round ridges on the tray cubes will get stuck. If you push up 4-5 cubes by hand up your tray, is there any difficulty or bumps along the way?

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our tray is not 100% smooth. I will try to experiment with that later, as we have sliders. I will look for excessive friction on tray.

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I would make sure you don’t have any screws that touch the flat side of the tray cubes often catch on screws on the tray. If you must have a screw in contact with the flat side of the tray, I would recommend countersinking screws to be flush with the metal.


Jamming? You will actually want to DECREASE compression. Seems like you have slightly too much compression, you want to find that sweet spot where there is just enough, but not so much that the cubes start to jam up top. As for intaking more than 10 cubes: this may have something to do with the angle of your tray. Lowering it will move your C of G further back, making you more prone to tipping. However, it will decrease the stress on the motors, making it easier to intake more cubes.


Lowering your tray angle will also make it harder for your tray tilter to push your tray, so depending on your geometry and gear ratio, stacking 10+ cubes may not be possible if you lower your tray angle.

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If you have good geometry, a 1:7 can get 13 cubes easy.

My geometry is decent, and with me pushing back on the tray, it can get 10. 1:7 100rpm

45 ish degree tray angle

Your current tray design looks fine. The intake jams are probably caused by cubes twisting in the tray. Try moving the intake wings inwards so that they almost touch the cubes. As for compression, moving the Intakes closer together would help, banding wouldn’t really do as much since your intakes are still the same distance apart.

Banding on hinges does a lot, because they move a bit.

Why do the intakes have this