AT CAD Team/AT elevator
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The AT elevator is a simple, lightweight and cheap elevator.
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[edit] Usefulness as AT design
Atleast for some (more advanced AT) designs I made, elevators are much more useful than stairs, ladders, rack-and-pinion lifts, paternoster lifts, and scissor lifts. This as stairs consume a lot of space, and ladders are not useful if loads (eg supplies) need to be transported into a building, and they also require some agility (which may be a problem for older people). rack-and-pinion lifts, and scissor lifts are also less usable than elevators as elevators use cables which are more cost-effective (they don't need rails on each side of the elevator, nor pistons).
The AT elevator design will thus definitly be useful in an AT context, if exclusively used for cargo transport and transport of people who are not agile enough to use neither stairs, ladders nor the climbing harness.
People that are agile enough can simply use the climbing harness instead.
[edit] Design specifics
In order to have any elevator able to accomply to AT (unlike the present-day elevators), some specific requirements needed to be attained in regards to manufacturing cost, power consumption, ...
In general, the AT elevator design consists of a light structure, comprised of only a platform (from a light material ie wood) and no doors, suspended using cables.
Offcourse there is a minor increased safety risk when comparing this elevator design to the contemporary elevator design, but the fact that it finally allows the use of an elevator at all (as opposed to ie ladders/stairs) in developing countries, outweighs the risks. Also, a simple design as this requires far lower maintenance and/or maintenance costs. This is an issue in developing countries and maintenance is not always followed as mandated by law.
In order to keep the safety risks small, an automated stop has been introduced after every few meters of altitude change. This job is done by the left winch in the schematic at this page. As can be clearly seen, it consists of 2 gears on an axle which has a ratchet mechanism on either side. When moving up, the back rachet mechanism is in operation and the ratchet on the front is deactivated (stop is moved away from gear). When moving down, the same actions happen with the opposite gears.
The right winch is the winch that provides the actual pulling/releasing of the main rope suspending the elevator platform.
Regarding the danger of overloading: this is indeed present and careful consideration has to be taken what kind of cargo will be transported with the lift, aswell as the amount. It will need to be calculated out what the possible weight of the elevator would be when loaded up entirely with the kind of cargo that will normally be winched up/down. For example, the weight of iron is almost 8000 kg/m³. Thus for a platform of 2m² (and with 2m of altitude), this would mean 64000 kg. Then, the design has to be revised and/or adapted to make sure that both the cabin itself will hold up the weight, and the engine will be capable of winching up/down the maximum possible weight. Also, the cabin should be equipped with a plate marking the weight the elevator can hold.
Also, it may be a good idea to size the platform to something that would not easily allow overloading, with the kind of cargo that is generally transported (and with the elevator filled to its full capacity).
[edit] Operation of the elevator
In the cabin of the elevator itself, there would not be a control panel. Instead, a control panel is available on each floor (the control panel on the drawing is actually for the the climbing harness winch, but the panel would be exactly the same; note that there would thus be 2 panels in a building that is also equipped with the AT elevator).
In general, there is one button that can be pushed and then sends the elevator cabin to the floor where the person has pushed the button. Then, the person can select a floor the cabin needs to travel to. There is then a small delay before the winch engages, providing time for the person to get inside the cabin.
For the climbing harness winch, the operation is similar. However, given the fact that there are no doors on any floor, there is a "safety rail". This rail is basically a rail unto which the wearer of the harness can attach a carabiner unto, so that he might go to the edge of the floor in safety. Once there, he clicks on the carabiner of the cable that has been sent down unto his harness, and removes the first line (safety line). Then, on the control panel, the person selects to where the winch needs to travel, and the person is winched up/down to the desired floor.
[edit] See also
- Multipurpose clothing design at wikiversity: includes the climbing harness described here
- Floating city design; uses the elevator design described here
- watchtower sleeping room
- AT crane
