Hacker News new | ask | show | jobs
by gvb 5206 days ago
Depending on the failure, you could fall up rather than down since the elevator is counterweighted. If the cable breaks, the car will fall down. However, if the drive train breaks in a car that is loaded less than the counterweight (very likely), the car will likely fall up since the counterweight will weight more than the car. My MechEng prof in college was involved as an expert witness in a case of this: the bolts holding the drive pulley sheared, letting the pulley free-run. Bad.

Interestingly, Otis is famous for his invention of the elevator safety brake. http://www.ideafinder.com/history/inventions/elevator.htm

1 comments

According to this New Yorker story: http://www.newyorker.com/reporting/2008/04/21/080421fa_fact_...

There are almost no cases of an elevator's cable just snapping and going into downwards free fall - with the exception of (possibly) during 9/11 and an incident in 1945 where a bomber pilot rammed a building. The elevator operator dropped 75 floors but miraculously survived:

> One of them fell from the seventy-fifth floor with a woman aboard—an elevator operator. (The operator of the other one had stepped out for a cigarette.) By the time the car crashed into the buffer in the pit (a hydraulic truncheon designed to be a cushion of last resort), a thousand feet of cable had piled up beneath it, serving as a kind of spring. A pillow of air pressure, as the speeding car compressed the air in the shaft, may have helped ease the impact as well. Still, the landing was not soft. The car’s walls buckled, and steel debris tore up through the floor. It was the woman’s good fortune to be cowering in a corner when the car hit. She was severely injured but alive

So maybe it's better to ignore the MIT guy's advice and cower in the corner.