How don’t know how to attach the cho Cho to the catapult. Please help me.
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I wouldn’t do a choo choo mechanism, try a winch.
watch Chuwbotcta’s video for their design. Trust me, It is crazy!
So on your advice I went here: https://www.youtube.com/watch?v=fAn5XM6vOHw
and watched. Very good video. I also looked at their submission to RECF of the PDF they wrote https://challenges.robotevents.com/uploads/0025036_original.pdf which is also very nice.
Thanks for the tip!
(There are a number of other cool entries this year, check them out. Entries for Build Instruction Guide - Middle School | Online Challenges )
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… of a one motor choo choo. It uses two side mounted Choo Choos with a common drive shaft. ( I linked to the info above in this thread)
We recently had a snow day, so I took the two hours I would have spent in class and built this. It’s a quick build, one of the best things about the printed plans is they tell you up front all the parts you need. (Hint Hint VEX Hero bot designers) It took me about 20 minutes to pull all of the parts out of respective bins and sort into the trays I like to build out of. Build time was about an hour for the catapult (mostly because I lack hole counting skills).
I then mounted 2x Wide, 7x Pitch Diameter Balloon Tires on the back and omini’s on the front and drove only the rear wheels. The extra height of the balloon tires gave clearance to keep the choo choo gears off the floor. The front omni’s help with the turning. I could have messed with mounting points, but I had the Ballon tires available. It also makes the robot go faster due to the larger diameter of the tires. And it has that tilted dragster look for style points.
I made the front part of the arm longer to be able to load from the floor. (2x20 and 2x18 were tried) This means changing the front support some, continuing my love hate relationship with 0x3 pins. I love to use them, I hate taking them out.
A very janky 2x2 sprocket stack was used to feed the balls from the floor into the basket. The front of the sprocket stack was supported by an axle support being used as a side. (I love these, and would like to see them sold in an SKU) The bottom sprocket bands were set up with reduced centers to pull the ball into the center, the upper sprocket bands were flat to push the ball into the basket.
With the extra length arm, it needed 2 #64 bands per side, total of 4 to power the launcher. The motor did not have any problems pulling the arm down. I was able to score 10 balls into the low goal in a one minute period. (Before the arm extension, it would score both high and low goals) (YMMV, I was by myself and eye / hand coordination getting it from the pickup zone to the robot intake was chaotic at best)
Kudos again to Chuwbotcta and their solid, buildable design. I hope they do well in the on-line contest, they have the entire package of step by step and the matching video.
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Could you show us a picture of this?
I also really like ChewBotca’s choo-choo design. If I had saw this at the beginning of the season, I may have used one for my robot.
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I’ll work on getting one. I left it at one of the schools , I won’t be there again until the 27th.
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