hey guys! ever thought the way a screw jack lifts your car? power screw threads are used to transmit torque and lift weights. so we can turn the screw jack even with a single hand. effectively speaking we can lift the car with a single hand. what if this is applied to elevators? we can make the elevator outer shell surface screwed, and then the inner cabin where we ride can be made stationary. the screw thread on the outer shell mates with a similar screw thread on the inner walls of the shaft. now lets rotate the elevator. it will go up. no need of cables, no counterweights... just a motor at the bottom of the cabin and a gear box. whats more, if we have a multiple start thread, we can lift ourselfs to a greater height in lesser rotations of the cab. Sounds as if you are riding a tornado isnt it? We can lock it stationary to the walls at any required elevation(so that the elevator stops at floors) by brakes(ejecting when desired) that grip into vertical slots cut in the walls.

A small modification suggested by a reader would do good... have a slot in the adjacent wall into which the motor locks and slides, so that the motor itselft does not rotate.
-- sridhar236, Feb 02 2005

Double Helix Escalators Double_20Helix_20Escalators
Similar [hippo, Feb 02 2005]

Elevating History Timeline http://www.theeleva...um.org/timeline.htm
some early elevators were screw driven [FarmerJohn, Feb 02 2005]

Acme Screw Drive Mechanisms http://www.techno-i...TML/H860P019_1.html
[half, Feb 03 2005]

I can see everybody now on their way to work, stuck to the outside walls close to passing out and - ding! 21st floor . . and everybody falls on the ground in a heap.
-- benfrost, Feb 02 2005


How do you envision the portal the passengers go through to get in and out of the elevator car?
-- bristolz, Feb 02 2005


Perhaps it ould be better to have two rings on the outside of the car rotate, at leave the rest stationary.

If you replace the threads with grooves, the car can be close enough to the edge of the tube that the doors can be like regular elevator doors.
-- Cats Whiskers, Feb 02 2005


Remember that veritcal motion would depend on the granularity of the screw (how close the threads are to horizontal - I don't know what the term is) and the speed of revolution.
If the screw thread is very tightly wound and near horizontal then, like a gearing, it will take many turns but at a low power. I suspect that to operate a lift you would have to do it that way .. and there would be a lot of friction on the screw.
-- Jinbish, Feb 02 2005


Thread pitch, I think.
-- bristolz, Feb 02 2005


Isn't there a big difference between rotating the lightweight screwjack and rotating the heavy elevator? In the screwjack example, the main weight is in the automobile, which hardly moves at all. The automobile doesn't have to rotate. With the heavy elevator rotating so much, there is a lot more total work required. I think [Cat's Whiskers] "Rings" would solve this problem, assuming the rings are lightweight. But then you don't get the fun of spinning...
-- robinism, Feb 02 2005


Modern systems do not _need_ counterweights - the system could operate with a big winch drum at the top of the building. However, using a counterweight effectively eliminates the weight of the lift from the system, so the drive motor only needs to lift the weight of the passengers.

If you remove the counterweight, your motor needs to be big enough to lift the entire weight of the lift and its payload. Installing this large motor on the lift itself will exacerbate the problem.

Although the screw-thread mechanism would allow the use of a smaller motor, it would do so at the expense of a slower rate of climb. If you wanted to go at the same speed as a conventional lift, you would need a much bigger motor to overcome the problems outlined above.

However, if motor power is not an issue then this could work. There may be situations where it is advantageous; I don't know.
-- david_scothern, Apr 27 2005


This is very silly.
First, the counterweight issue is a red herring. Regardless of how you lift the elevator, counterweights offset the total energy you need to put in (since you are reducing the net mass x height gain). So, counterwights will help a cable- drawn lift, and they will help your helical lift. This isn't the issue.

Second, and more importantly, you are just using the shallow helix of the thread as a gearing system, and it is a very cumbersome one compared to the conventional gears in cable-drawn lifts.

For instance, suppose your thread rises one inch for every turn, then one revolution of your motor lifts the elevator one inch. But in a conventional lift, gears do exactly the same thing: one turn of the motor is geared so that it pulls the cable one inch (or whatever figure you choose). With even the teeniest electric motor, you can lift any weight of elevator you like - you just trade speed for force.

So, your helical system is just a different configuration of gears, and is going to waste a lot more energy in friction (and be costlier to install) than the normal gearing system.
-- Basepair, Apr 28 2005


What I like about this is that it allows for multiple cars in one shaft, allowing for taller skyscrapers...
-- cloudface, Apr 28 2005



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