So I have been researching Mechanical dumbwaiter/elevators and have stumbled upon an interesting part of the system I have only found this on dumbwaiters and not hand elevators. The pulley system somehow holds the load no matter which end is the heaviest. Just see the video
So if anyone knows how this works that would be great, also is there a name for the part that holds the load and if so can you still buy them if you wanted to make a new hand powered dumbwaiter? Also why didn't they just utelise a worm drive?
