Cable Down
A Cheaper Method of Rapid Egress from Skyscrapers

T   
he method of the previous article "The Dead Drop" is undoubtedly too costly to be implemented. So I have another idea for getting them out fast (though not as fast as a drop chute). This involves the deployment of a steel cable from each floor. The "jumpers" must put on a gizmo (a harness) which they attach to the cable ... then jump ... and the system does the rest.

Here is a picture of what I mean.

Basic Cable Setup - 5kb When the need arises, a steel cable (not too much unlike a suspension bridge cable but not so heavy duty) is drawn out of its enclosed space on the side of the building by a "cable car type" pulley system along the plaza. It moves out in an arc so that the end point for any cable is away from others. The end of the cable is attached to a upright post about eight feet tall so that when the jumper comes down the cable he arrives at the end suspended a foot or so off the ground (not dragging along the ground).

Where the cable ends there are some fixed smooth concrete benches where people can sit but may be also used to stand on when the firemen remove the jumpers from the cable. Some may arrive unconscious from the scare (not from physical damage) and they must be gotten out of the way of the next jumper.

Now the big question is ...

How do you slide people down a steel cable in a controlled manner without any need for them to do anything?
The answer is that they don a harness that looks like a pair of Bermuda shorts with suspenders and a curious metal clamp gizmo attached to the suspenders. The design of the gizmo is the crux of the matter.

The reason I want them to look like pants is so that no one will put them on backwards or upside down or in any way confuse how the thing goes. They have no time for head work and probably wouldn't be in a sound state of mind at this juncture.

Here's the clamp gizmo

cabledn2.gif - 6kb The gizmo is enlarged to show up with the pants. One pants strap is permanently attached to the gizmo so they can't get separated. You wrap the gizmo around the cable and secure it with the hook on the other strap, making sure that you hook it through BOTH steel loops A and B on the gizmo.

Now, you're ready to rumble.

The Drop

When you jump from the top floor (here ~2000 feet up), you may achieve a speed of ... hmmmm ... 90 mph? The gizmo is touching the cable somewhat ... but when you get nearer the posts you take your G's and the friction in the gizmo increases dramatically. What is it made of? I think this is a question for the automobile industry. They are the ones with mucho experience at stopping a mass by friction.

It may be, possibly, aluminum. This metal is soft and conducts heat rapidly. It won't wear away the cable to any significant degree but will instead absorb the energy of the drop by way of heat and abrasion. There may be other more suitable materials. Suffice it to say that it would be fairly easy to stop a human body going 90 mph in a distance of say, 200 feet. The problem will be to get them off the hook quickly enough so that the next man won't be running into them. Especially true if the jumper loses consciousness from fear or heart attack.

Presumably there will be firemen and assorted other helpers standing on the afformentioned benches to assist in the bailout.

At the Top

There will be a "dropmaster" at the top of the drop who attaches the gizmo to the cable. He will be one of a dozen or two trained in the use of this system who also happen to be an employees of some businesses on that particular floor. This will ensure that there is always someone who understands the system and who has a "key" to unlock the jump doors (after all, you can't just be able to open the door at will or there will be many suicides).

The Jump Door Mechanism

The Jump Room - 5kb This is fairly self-explanatory.

A part of the floor slides out with two sides (one side open to jump). The dropmaster stands by the slot in the wall (he has key to open slot which allows the floor to extend as well) ... and hooks the next jumper's gizmo onto the cable. The jumper then walks into the extended drop area and jumps (or faints and falls). Next!

It's not as passive as the dead drop, but it's much cheaper and could be fine tuned into a really workable system. I think you could evacuate my 160 story building in as little as 15 minutes (with minimal casualties). Anyway, if you sere stuck above a fire ... you'd still have a genuine fighting chance.

A Possible Problem

The cable is draped in a catenary curve. That's OK. I'm somewhat concerned that a standing wave could develop going up and down the cable ... and ... if the jumpers went out with paratrooper regularity, it might fail by way of resonance. That is, not break but rather throw someone "loose" as in "to the ground". They must go down at random times like 5 seconds ... then 7 seconds ... then after 4 seconds ... then after 10.5 seconds ... etc.

Also, it may be difficult to arrange the cables so that they do not interfere with one another ... perhaps every other floor or some other arrangement. Certainly, I have less confidence here than with the dead drop.


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