This idea would be easier to explain as an illustration, but I'm not an artist, so feel free to do it for me if you like. Anyway, the ladder has tracks on the sides with footstands like on the back of a bicycle and then you have a handlebar release that allows you to basically "ride" down the sides of the ladder where you hit the bottom and there are springs that safely bounce you to a stop. Does this make sense to everyone?
-- goober, Dec 18 2006

kinda like two of these set together to look like a ladder with footholds on the side? http://www.dailymai...093&in_page_id=1770
these are banned on grounds of H & S, bah. [po, Dec 18 2006]

Hello, [goober]! It has been a while.

Brakes, not springs. Springs actually increase the force experienced at the bottom. Spreads it out a little bit, but doubles it.
-- lurch, Dec 18 2006


It has been too long. Springs wouldn't work, huh? I was trying to keep it cheap, but maybe hydraulics need to be involved here...or giant sacs of custard to slow you down!...or cats to land on at the bottom!
-- goober, Dec 18 2006


[lurch] How does landing on a spring lead to a doubling of force. Doesn't that violate the laws of the physical universe?

Wouldn't a spring cause a deceleration followed by a re-acceleration of somewhat lesser magnitude. by my math this would lead to a force experience of no more than 1/2 of that experienced if there were no stop at all(i.e. concrete) Depending on the spring rate the deceleration would not be linear, nor would the re-acceleration. I think this would be a roughly logarithmic increase in the force experienced over time by the user, the amount of time of course being determined by the strength and length of the spring.
-- jhomrighaus, Dec 18 2006


Yes, you're right - peak force would be lower. The total force applied integrated over the total duration of the collision will be double, minus whatever is converted to heat / sound / deformed (in the kinematic sense) muscles / deformed tendons / deformed bones (ow ow ow). I'm just used to thinking in terms of elastic or inelastic collision, like where if you catch a baseball you transfer less total energy than if it bounces off the back of your head (in which case, the energy to accelerate it away again has to come from somewhere, in order to obey them stupid rules of Newton's).

Hasn't MythBusters done the one with the spring-bottomed safety elevator?
-- lurch, Dec 19 2006



random, halfbakery