The intake lift problem

So my team is split on the way to lift the arm. The arm is connected to a gear on one side and rollers on the other side. There is nothing to hold to the arms besides that. Some people in my team want to put another shorter c channel and connect it like a 4 bar would. The bottom c channel is not connected to any gears. It’s just the actual arm. Screenshot_2019-11-14-18-52-53

Attaching pictures would be useful.

I want to add pic’s but I don’t know how to

Click the upload button at the top, the one that looks like a rectangle with an arrow going upward. Then, click “choose files” and choose the picture.

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Thanks for telling me how to get a pic on. I put a pic on the first message.

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I don’t see much of a use for the extra bit besides easier rubber banding. Personally it seems like it would be simpler to use rubber bands on the back of the arm.

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The thing is that the tray kind of gets in the way. Do you have a suggestion to improve that. I can get pic If you want.

If you aren’t pushing the limits in size then you would just need to make the arms longer and rubber band it to make it lift better.

However I don’t see the current setup being ineffective, but it does seem like one more thing to break.

So. A quick update. Like I expected it wouldn’t work at all. The bottom c channel was too short so it can’t go up enough (talking about the arms) It didn’t make it better. It might have made it worst. So we took it off.

Why are your rubber bands on the diagonal that is pushing the arm down and not helping motors to lift?

If you switch rubber bands to the other diagonal they will help the motors.

Look at Goofy. It doesn’t have four bar but has good crossbracing for the arms and lifts with one 100rpm motor.

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My team uses a set up like yours, but we rubber banded them:


It looks like that’s already what you have. This solution works fine, and unless it gets in the way of something, there isn’t much need to change it. If you wanted to switch to just a 2 bar, you could rubber band it like this


We took it off because I stopped thw arm from going up high enough

Your current banding set up is fine. The only thing wrong with it is the direction that it is going in. You should be rubber banding the two corners that pull the diamond together and pull the lift up, instead of pulling it apart and pushing the lift down.

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That’s what they did. The bands would have to be attached to the vertical bars to pull the lift down.

If you are rubber banding your lift, I think this is the simplest solution. In addition, If you do it properly the lift can rotate past 180 degrees with near-linear tension.


That is really useful. Thank you so much

in fact, it is possible to rubber band a lift up using the vertical bars. you need to understand that when the lift is going up, certain corners are coming closer together. As long as you rubber band those two corners together, it should rubber band up, regardless of whether or not the bars are vertical or horizontal.

I encourage you to try this yourself.