Banebots 42mm gearbox: Recommendations for use

[ZZII 527]

Thanks so much for your efforts to analyze and solve this problem over the past few days, Dr. Joe. My team is in the "fortunate" situation of having a 12:1 single CIM drive system, but I am worried about our arm which is driven by the 256:1 42mm transmission with FP motor. While I don't anticipate the motor ever being driven to anywhere near stall, I tend to think that impulsive loading from the arm itself is the thing to watch out for.

I can easily imagine a large arm changing directions in a matter of milliseconds, hitting a dead stop, or gaining momentum before a chain engages and suddenly yanking on the drive shaft with much more torque the the FP could supply. And at 256:1, the gearbox would have very little give from backdrive at those time scales. A good test might be to short the motor terminals (worst-case scenario with Victor e-brakes on?) and drop a weight from an arm attached to the shaft. I bet it could do a lot of damage.

If this is the more likely way to get failure, then there are a bunch of ways for teams to alleviate the problem, many of which were mentioned in previous threads (gas springs, limit switches, etc.). Do you think this could be the more dangerous culprit, or am I missing something important?