Quote:
Originally Posted by Jared341
I have often heard that cascaded elevators require a return drum of a different diameter than the feed. But wouldn't the following work?
Each segment of the elevator can have a closed loop of belt/chain attaching it to the prior stage. It should be anchored at the top of the previous stage (or motor for the first stage), and the bottom of the next stage. It's important that the total length of the loop doesn't change as it travels up and down.
You still have the speed and force multiplier effect with each stage, but you won't have to worry different feed and return speeds.
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My aging brain is not visualizing this, perhaps you could sketch it. The purpose of a return/take-up cable is to drive the elevator down as well as up. You could create a closed loop cable between the 2nd and 3rd stage, but it would not drive the 3rd stage. Remember that the lift cable for the 3rd stage is anchored to the 1st stage, not the 2nd. It therefore needs a corresponding return cable which is also based on the 1st stage (the 2X take-up). It is a closed loop overall, but not between stages.
We solved the 2X take-up issue by making our winch drum a 2-stage drum (photo) with the return stage 2X diameter of the payout stage. Made the cable rigging quite simple.