--The trouble with ropes: they're easy to go down but hell to climb. That's why the Jumar was invented, yes? But these are cantankerous at best. So howzabout making a rope with a core of braided Nitinol wire, aka 'shape memory alloy' (braiding the stuff increases its power considerably). The wire could be "programmed" so that when energized it puts a 90 degree kink in the rope every 15", followed by a reverse kink, say, every 6" or so. This makes for a narrow step, but that way it doesn't shorten the rope too much. --Thot this one up while passing the local fire station; the flag's at half staff due to the deaths of those nine guys who fell thru a roof. Maybe some of 'em could have gotten out with a ladder, even a crude one?
-- Steamboat, Jun 24 2007

THAt's how they do it. http://www.harrypri...irewalk/karachi.jpg
[2 fries shy of a happy meal, Jun 27 2007]

Good old Wikipedia http://en.wikipedia.org/wiki/Nitinol
Nitinol article, needs work. [TheLightsAreOnBut, Jun 27 2007]

I had a similar idea a while back, but instead of the rope becoming a ladder, which you have to climb, (assuming the top of the rope is attached to something) you grab the end of the rope and it coils itself up, lifting you in the process. It all depends on just how capable the braided Nitinol is.
-- neutrinos_shadow, Jun 24 2007


So do you have different ropes for different ambient temperatures, keeping it at a different temperature in a container until needed? Or are you heating and cooling the rope with some sort of internal system?
-- Galbinus_Caeli, Jun 25 2007


Nitinol is typically activated via electrical current, so I'm thinking a battery attached to the rope would do the trick; maybe an extreme jerk or a temperature spike could close a circuit? Nitinol loses its memory around 900 deg F and I'm sure fires get hotter than that, but if it's inside a rope I'm thinking the rope would melt at a lower temperature than this, so circumstances would behoove one to get the heck out of a situation before, or shortly after the flames start licking around one's ankles..
-- Steamboat, Jun 27 2007


// Nitinol is typically activated via electrical current

Err, no. Nitinol is typically activated via temperature (see Wikipedia article)

It may lose its memory at 900F, but it's shape memory trigger will necessarily be at a lower temperature than that.

Other triggers (depending on the formulation) such as stress (it behaves like a super elastic, as is found in dental wires) or electric current, only mimic the temperature change that triggers the shape memory effect.

You'd have to formulate it to trigger at a threshold temperature over which no human could survive anyway, and then do your electric current thing. I don't know whether that would melt the outer fibres of the rope, though. Maybe consider shape memory polymers with a uv trigger instead? Don't know what power potential those have - don't know what power potential Nitinol has, either.
-- TheLightsAreOnBut, Jun 27 2007


As the flames lick at your feet, you can climb the first rung, until the flames lick at your feet and you can climb the next rung, until...

But more appropriately, an exothermic chemical reaction (fire-agara) could be triggered in the core of the rope to erect it, with the outside contained in an insulating sheath.
-- Ling, Jun 27 2007



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