2 CIM Motor Winch

[Jon Stratis]

Originally Posted by Kevin Sevcik

2 CIMs should be plenty to lift a robot, as long as they're geared properly. What's the diameter of the pulley on your winch? Is the 60-24 ratio an additional gear down after the ball shifter?

*poke* winch diameter is part of the gear ratio. If they're using the 60:24 3rd stage, then low gear is 20.8 to 1. Which would be plenty on a 1" radius pulley, but completely hopeless on a 6" radius pulley.

My assumption, based on their post, was that the total active gear ratio they were using to climb was 60:24, as no other information was given. Even with just a 1/2" diameter, that wouldn't suffice - the ratio is still way off unless there's another stage he's not telling us about. Yes, winch diameter plays a big part in the overall gear ratio, but one thing at a time... get the gearbox to an acceptable range, and then you can size your winch according to that.

This is going to be the third time I've built a winch mechanism to climb with my team - Ultimate Ascent and BreakAway being the other two. In designing them, it all starts with the proper gear ratios in the gearbox, then moves on to the winch. It's just easier to size the winch appropriately than it is to change a gear ratio by just a little bit.