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Unread 05-01-2012, 00:28
Mr. Lim Mr. Lim is offline
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Re: pic: Unobtainium 6wd - Cantilevered, Dead-Axle, Slot-Tensioned Drivetrain

Quote:
Originally Posted by squirrel View Post
Stover lock nuts, you mean?

I suggest you might want to find or figure out how to make a more substantial washer. Our design used large hex flanged nuts. You might be able to do this too, and use 1/2" fine thread threaded rod for the axle as we did. We used two jam nuts to retain the wheels, but this required that whoever was working on the robot needed to know not to tighten the nut too much!
I saw the CAD of 1726's 2008 robot way back in the day, but back then I didn't realize it was 1/8" C-channel for the side rails. I thought it was box, and the cantilevered shafts were supported at two points. Missed that one big time.

And here I thought this was an original idea .

The flanged Stover lock nuts look pretty nice, and I think they would go a long way to improving the design. Placing one on either side of the plate instead of the washers, upsizing to a 1/2" shaft of fine threaded rod and two jam nuts to keep the wheels from falling off seems to be the direction I'd like to go in... and then an FEA.

Questions:
Did your wheel bearings rest on the threads of your threaded rod? If so, any concerns with this? Excessive play? Still worth the trade-off IMO, but curious nonetheless.

Did you have frame flex issues at competition weight? Did you have to add more support to your C-channel side rails to prevent them from twisting, resulting in negative camber?

Was that a typo, or was your fibreglass C-channel really only 1/8" thick?

Thanks all who posted in this thread who shared their comments and concerns (yes, that includes you Dr. Joe!).

Really, as a programming and electronics guy, if I can't get the mechanical guys to cringe at least once or twice a day, I'm not doing my job right .

Quote:
I believe that we humans utilize our emotional brains to sort through complex space of possible solutions. Our emotional brains are just really good at searching through complex system interactions.
P.S. If you believe in the quote above as much as I do, you need to read Malcolm Gladwell's book "Blink." Not just a blatant plug for a fellow Canadian, but his work really expounds on why some people are so good at what they do. There is so much more behind the "emotion" and "gut feelings" we get when working in our fields of expertise. The vast amount of experience and expertise we subconsciously put into honing those "feelings" allows us to correctly decipher really complex problems in the blink of en eye. Often without even realizing the vast amount of information we actually considered in the process.
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