Quote:
Originally Posted by ekapalka
Please excuse my lack of intelligence, but aside from using the Green Cord to spare your motors, what stopped you from simply using AndyMark gearboxes with that or a similar reduction (like a pair of 8.75:1 toughboxes with reduces by 2:1 on the output)? Is there some other mechanical advantage to using the gigantic sprockets? Thanks!
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I was scared of the impact loads we were going to put into the arm. So, I worried about going with a "live axle" where we transmit the torque to the arm via a hex shaft (or worse, a 1/2" round with a single key).
So... ...we went with a larget sprocket on the last stage because then we get to transfer the torque to the arm out at a nice (6" in our case) radius. Also, we have all those teeth engaged rather than just a tooth or two.
We went with the green cord on the first stage because it is springy and it can slip. This lets the energy in the armatures go someplace other than into breaking gear teeth and/or snapping chain.
COULD we make a Toughbox work? Maybe yes. But, we made the thing we had work so, I have an existence proof the system with chain and green cord working. I like that the loads are lower and the energy has someplace to go. So... ...unless I had a compelling reason to go another way, I wouldn't change.
Dr. Joe