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You know, how there are a TON of elevator shafts in office towers these days? The obvious solution is to eliminate cables altogether so multiple elevator cars can use the same shaft. Put some sort of motor on the elevator cars that allows them to move up and down (something like LIM motors would work).
Multiple
shafts (think train tracks) would accomodate passing elevator cars and be designed so cars can freely switch between them. A simple system of this type would use one up and one down shaft, with some sort of runaround at the top and bottom.
Horizontal elevators, for example, would become practical with this system.
(?) Elevators On The Move
http://home.fuse.ne.../elevatorfuture.htm
"Getting rid of the counterweight and the ropes is the quantum leap everyone is looking for," [tongpoo, Oct 17 2004]
[link]
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How do you power the elevators? Bumper-car style sparky catenaries? A fission pile on the bottom of each one? Passengers must turn crank? |
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Actually the cable is also part of a safety feature. When under tension the cable pulls levers that remove chock things from slots in the shaft walls, if the cable breaks then the chocks immediately spring into the slots and stop the lift. |
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I saw some cable-less lifts (elevators) recently. Each one
was supported by a huge piston sunk into the ground.
Negative points: You have to drill a hole in the ground as
deep as you want the lift shaft to be tall... Positive points:
It looked cool, and meant that there was no need for a
roomfull of winching gear on the roof. |
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Re hydraulic lifts, there are multi-stage hydraulic pistons, so the height of the cylinder would have to be only 1/3 or 1/4 the travel of the lift. |
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Otherwise, I don't see any particular problem with designing a lift which rides on tracks and uses friction wheels to propel itself up and down. Power and communication could easily be obtained by having contacts slide against non-moving cables or rails along the edge of the shaft. I don't think it would be worthwhile to run multiple cars in the shaft even with such a system (horizontal travel would be way too complicated) but it would have the advantage of saving the weight of hundreds of feet of cable. It would, however, have the disadvantage that counterweighting would be difficult or impossible. I don't know whether this latter disadvantage could be countered by using the motor as a regenerative brake during descent. |
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Schindler's SchindlerMobile is a self-driven ropeless elevator with wheels. Downside: a report by Otis says a system without a counterweight uses seven times more energy than the conventional elevator. The elevator cars from the movie "Minority Report" are cool, but unfortunately aren't real. Replacing ropes with pistons will not make it any easier to have multiple cars in the same shaft. |
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I think Buckminster Fuller had an idea for a mile-high building, and he 'solved' the problem of too many elevator shafts by proposing that each elevator be like a vertical train (ie, multiple decks). Today, double-deck elevators are already common (google: wiki double-deck elevator). |
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And I'm sure that elevator companies are exploiting computing power to make managing multi-deck elevators are reality. |
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So, this idea isn't half baked at all. Its already been baked, sliced, and served with a cup of tea. |
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Is anyone else thinking of Willy Wonka in this connection? |
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There are plenty of possible mechanisms for multiple lifts in the same shaft, several of which could use counterweights (or use descending lifts as counterweights, or a combination of both) rather than using regenerative braking arrangements. You certainly don't need to dangle from cables to be able to use counterweights. |
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There are also credible mechanisms for lateral transfer between up and down shafts. |
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The Otis report simply shows that Otis didn't want to get involved in what they saw as a very expensive development program, when none of their competitors seemed likely to. |
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These things will come when (if) large numbers of extremely tall buildings start to be built. |
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I have always expected that elevators would first be converted to normally operate one-way operation with loopovers at the top and bottom connecting all the shafts and connecting at the top of the intermediate banks. When most cars are descending, for example, one shaft would be the return and would be practically solid with cars.
Near rush hour, computers would queue up extra cars at the top and bottom on sidings. It is easy to imagine switching from track to track should a car be held so that following cars would not have to wait. |
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I think I would prefer to see a toothed rack, running up the side of the shaft, and a motor with a pinion wheel on the elevator car, rather than a linear electric motor. Power would be via conductor rails. |
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