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Unread 19-05-2011, 16:09
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Karthik Karthik is offline
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Re: Sheet Metal vs KitBot

Quote:
Originally Posted by MentorOfSteel View Post
Thanks for pointing this out. As a FIRST newbie, I was extremely impressed by the quality and versatility of the kit chassis and drive train. It is a beautiful piece of engineering.

Team 3504 did something similar to "kit chassis on steroids" this year, but we had complications with chain tensioning system. In the video, it looks like the chain lengths just worked out without the need for extra tensioning, but that is not how it worked out for us. Is there a certain sprocket size you need to use? Is there some other trick we missed?

Thanks,
-George
As Dustin and Madison pointed out, if you use #35 chain and keep everything collinear, you can get the chain length to be exact and avoid using tensioners. This was done by properly spacing out out front and center wheels. For the other two chains between the gearbox and the wheels, the gearbox was mounted on slots and slid until it was in a position that worked. A half link may have been used to get things to be exact. Regardless, #35 chain is known to be pretty forgiving.

We built a kitbot on steroids (Simbot Ke$ha) and used it as a defense robot for our practice sessions. Ke$ha logged far more hours than any competition FRC robot would get in a season, and played constant, rough defense on 1114 (as well as 1503 and 2056). Despite this constant abuse it survived from October until now with minimal repairs and no tensioning issues.
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:: Karthik Kanagasabapathy ::
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Full disclosure: I work for IFI and VEX Robotics, and am the Chairman of the VEX Robotics and VEX IQ Game Design Committees
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