http://www.clickondetroit.com/news/3920896/detail.html

How many elements have to fail for a counterweight to free fall, causing the elevator to crash into the top of the shaft?

Most likely cause? Besides poor maintenance and inspections?

-- Gary Bouwkamp (gbouwkamp@gmail.com), November 16, 2004

Answers

I watched the news video and the reporter said that a cable broke. The only thing I can think of that could have happened was the governor rope could have broken, then the electrical safties would not work. Then the elevator had to miss an up step or slowndown as well as a secondary set of slowdown switches at the top causing the counterweights to slam into the buffers. All would be due to poor maintenance and code infractions (safties jumped out).

-- Rodney Pearcy (classicgm@charter.net), December 08, 2004.

freefall

I am not familliar with the story but I have seen what happens on a Dover machine when a brake pin shears off. Some styles are hard to check without complete disassembly; something that should be done annually on these particulr machines.

-- (Kennykbe@hotmail.com), January 06, 2005.

There was a failure in the worm/ring gear (as in teeth sheered off). The car was @ or near the 1st landing when it happened. The car basicly went into an upward freefall (for lack of a better term). I don't want to comment on the cause as an investigation is still pending as far as I know.

-- Trapper (skidoo@comcast.net), January 11, 2005.