Hello,

We have a residential building elevator crashed in the pit, it dropped from the 1st floor, it was coming from the 6th floor and should have been stopped in the 1st floor, but it crashed with the absorber,(it was overloading with people)......people inside the car are telling different story, some say it dropped directly from the 6th floor to the pit, others say it stopped in the 1st floor then dropped from the 1st floor to the pit, what are the probabilities for both cases?

It was overloaded...dont need anymore reasons than that!!!! cant stop stupidity of people

What I'm aiming for is really the analysis of the problem, why the governor didn't work? why the limit switch didn't work? is the elevator brake has an issue? inverter problem?.....etc.

no too much weight in the lift, It wouldnt have "crashed" from the 6th floor...people have NO sense of reality when they are stuck in a lift. Obviously you are NOT in the industry as you would understand how when a lift is OVERLOADED and slips through the brake that NOTHING will stop it untill it hits the buffer, the lift didnt overspeed that why the governer didnt trip the limit WONT work when the lift is sliding thru the brake and certainly not a drive problm...get over it if the people are stupid enough to overload the lift then they get what they deserve!!!

Thanks for the answer, but as my understand, elevators when overloaded won't even move, the electric motor will be disconnected automatically from the beginning.

Is it a hydraulic elevator or a traction elevator ?

It's a traction elevator.

Again, if the lift is overloaded it still CAN slip through the brake (no matter how good it is), no amount of limit switches and overspeed devices (and if it does slip through the brake the govenor WONT activate because its not going fast enough and if the overspeed switch trips(NOT the mechanical govener)does trip wont stop the lift from sliding..obviously you dont know lifts and are looking for an excuse to blame the lift service contractor, if you are that worried employ a consultant (gee never though id say that) to survey the lift. We cant give an analysis as we DONT know the condition of the lift and DONT know the circumstances behind it.

The term "broke traction" is used to describe when the elevator hoist ropes slip on the driving sheave. This typically happens as a result of poor maintenance, poor engineering design and overloading.

It will happen with counter weighted traction elevators that are lightly loaded at the top floor causing the car to drift into the overhead and counter weighted overloaded traction elevators at the bottom floor causing the car to drift into the buffers.

George Gibson has a DVD available from elevator world book store that describes in great detail about the physics and math about this.

The building owner is to blame here because it is their building. As building owners and managers move to the "cheaper is better" paradigm, it causes them to neglect principals that are known and have been known for many years. (Thank you Sir Issac Newton Jr.) It's making a tidy little niche market for under employed attorneys to shake down the building owners and their insurance providers for such ignorance. For some reason the people who overloaded the lift are seen as exempt from the part they played by obviously overloading the elevator.

It is most likely that the lift failed to stop and continued to drift to the pit from the terminal floor. It would most likely have been traveling at rated speed or less when broke traction and struck the buffers. In some extreme cases, it could happen when the load is put on the lift.

Hollister Whitney has a great product that can mitigate such incidents. It's called the rope gripper and prevents unintended movement of the car.

Will the owner put one in after the horse has left the barn? Please keep us posted.

Respectfully Submitted.

Scientific method requires examination of the evidence first-hand, then reaching a rational conclusion, based on the evidence. It has not been proven whether the lift broke traction, or slipped through the brake, or some other issue occured. Without expert examination of the equipment, no definite conclusions can reached at this time.

What is almost a cetainty, is that it DID NOT "drop" from the 6th floor, in a true freefall, as the public is so very fond of imagining. There is no way for the passengers to know exactly what the elevator did, without having the advantage of visual refrence. When you are "blind" inside a box, the theater of the mind conjures up the most fantastic scenarios, compounded by the fear of the unknown. The pit of one's stomach is not an arbiter of velocity, nor direction of travel. For example, a change in velocity in a given direction, is often reported as a change in direction, when that in fact is not the case. The Star Tours ride at Universal Studios doesn't move more than a few feet, but you'd swear your Tie Fighter was swooping down through chasms hundreds of feet deep in the Death Star. In the same manner, the publics' reporting of elevator motion is notoriously innacurate, especially with those who have a predisposition for being emotional.

In this case, if it had actually fallen without restriction, it would have most likely had structural damage, and serious injurys. (The buffer is not designed to dissipate impact from "terminal" velocity, but rather, closer to contract speed velocity) It is very likely that the lift slowed down for the bottom floor in the normal manner, then after stopping, (upon the normal removal of torque from the motor that was slowing it down), either slipped through the brake, (or broke traction), then slid into the buffer. Of course, there are other possibilities, but no evidence demands no verdict.

As has been said, in any case, the fact of the elevator being overloaded precipitated the event.

thats virtually what I have said ...in different terms...it seems that the original poster doesnt belive that a lift due to being overloaded (his terms) can and WILL slide thru the brake when overloaded...just ask any nightcall guys after attending a hotel/motel after a big night!!!

Yes, kiwinightstalker, I was aware that my post was covering some of the same ground. Your ideas were SO good, they bore repeating!

I thank you all for the comments, but is there a guide or reference to troubleshoot some common elevator problems? I'm really new to this thing.

aw shucks at least someone gives me credit!!!...LOL..all I was doing (hopefully) was agreeing to your post to reinforce to the original poster that when you overload a lift it CAN go into the buffer no matter how many saftey devices are fitted!!!. Actually the buffers did there job as it seems noone got hurt!!!!

The replies given by all these professionals were excellent answers to your question. Sounds like you need a reputable elevator company to send a licensed elevator man to take a look at this thing.
Did anyone seek medical attention? Not sure about residential elevators but if there is an alleged injury on a commercial elevator, it should be locked and tagged for a State Elevator Inspector to inspect before it is moved, worked on, or (in worst case) put back in service. He will try and determine if the negligence was on the part of the people riding (highest probably in this case), the elevator malfunctioning, the building owner and/or the elevator maintenance company - if there is one.

In total agreement with E-man above. Hamed , sir you need to realize that there is no room in this industry for people trying to self service something that has John Q.Public riding it. You are
taking unnecessary risk with peoples lives not to mention your own. Hire a licensed professional elevator company to fix your unit before someone seriously is injured.

Robert, the rope grippers aren't that useful, there way of act is depending on the safety circuit when the elevator leaves the door area, it will stop the elevator but not immediately, the elevator can stop between 2 levels (out of door area) and slip a little with a rope grippers on.

If you don't think an elevator will slide through the brake, just look on the car panel of any old single speed AC Machine. Those inching buttons are there for a reason..