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Unread 12-04-2004, 02:50
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ahecht ahecht is offline
'Luzer'
AKA: Zan
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Join Date: Dec 2001
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Location: Billerica, MA
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Re: Chain Drive Question

Quote:
Originally Posted by Grommit
That's a great way to keep the chain tensioned! I was curious about your bolt: did you have trouble with the bolt loosening in the competition? Did you use some kind of solution inside to increase friction so the bolt wouldn't slip? Or was that not a problem anyways? Also, was the sprocket shaft on a sliding slot or was there some other way to move the sprocket along?
We didn't have any trouble with the bolt loosening, but if it is a concern, you can coat the bolt with a very thin layer of locktite before inserting it (make sure the locktite is completely dry before inserting, as the solvent will melt the lexan). In 2k3 we had trouble with our chains popping off, but that was due to our flexible frame and flaws in our manually milled (not CNC) 80 tooth sprocket, not our chain tension.

The adjustable idler's shaft slid in a slot milled into the two lexan plates, relying on the tension in the chain to keep it pressed up againt the bolt. The fixed idler's shaft just fit into two holes.

Another thing to note is that if you don't need your motors spinning in the same direction (which we didn't this year because we could pneumatically lock the two sides of the driveline when we needed to go straight), it is possible to design the system without the stationary idler (thus having your chain make a 'z' shape).
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Zan Hecht

Scorekeeper: '05 Championship DaVinci Field/'10 WPI Regional
Co-Founder: WPI-EBOT Educational Robotics Program
Alumnus: WPI/Mass Academy Team #190
Alumnus (and founder): Oakwood Robotics Team #992


"Life is an odd numbered problem the answer isn't in the back of the book." — Anonymous WPI Student