Elevators: Cascaded vs Continuous

[Jared Russell]

Originally Posted by jspatz1

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.

Here is a picture of what I was envisioning.

The motor is directly connected to a continuous belt/chain/cable around only the first stage which is anchored to the bottom of the second stage. Thus the motor can drive the second stage both up and down. The rest of the system is constrained based on these two moving parts.

Basically, it is a conventional cascade lift, attached to a cascade "lowering" system.