Hi, our team is trying to add choo choo mechanism for catapult. the gears are not properly aligned. how to get them aligned properly? also, since we are using two motors, how to make both gears rotate at the same time? if one button is pressed before the other , the mechanism does not work properly.
2 Likes
I’d strongly suggest creating a motor group with those two motors. You can learn more about that here: https://youtu.be/nZlfjLDn8LQ?feature=shared and by doing some simple Googling. That will help solve the issue with keeping the motors in sync.
You can see that the gears are wobbling because of the force of the choo choo. That’s to be expected, so I’d suggest trying to find a way to create a larger plate/beam wall between the gears and motors.
Also, make sure you’re using metal shafts so that they’re strong enough and don’t bend.
A choo choo mechanism is an awesome choice for a catapult but there are a TON of variables that you’ll need to tinker with to get it just right for your build. That’s the beauty of the engineering process…just continue to iterate on your design, one variable at a time until you’ve got it tuned just right.
Good luck and please come back here to share an update on your progress!
5 Likes
Try designing a better gear ratio with the motors and more supports to keep the gears in place. Another idea is to space the gears apart more and then it may even out.
Coming back to add this since we can’t edit posts. You can also double all of the beams to make it more stable.
1 Like
Take a look at this link:
1 Like
Try to add standoffs between the beams.
If you can try to add connector pieces, they work best.
It kinda looks like the gear is bending because the two bars (The black ones) connecting are too wide. I would recommend trying to switch to one bar that is shared by both gears.
Sorry for delayed response. Thank you all for providing your valuable input. Motor group did solve one of the issues. Team is still facing an issue of bringing the arm all the way down for ball intake and hold it there until launch button is pressed. Any input on this is much appreciated. Thank you.
You are welcome. From what I understand, your choo-choo isn’t going down far enough to load. I would recommend elevating the mechanism and moving it closer to the “post” the catapult is connected to. This would fix it because the second beams (The black ones) are very long and are being pulled back by the short beams are too short to pull it down far enough. Also, most teams that have choo-choo’s on the base have a short “post” holding the catapult. You might even want to switch to a large gear, elevate it, move it back, then I think it should work. The angles are a little tricky. If you do all this and it still does not work, you can consider switching to a ratchet and winch.