It occurred to me this week that my children used to ask quite frequently if they could jump up and down while an elevator was in motion, because it was fun. I’ll allow that it might be fun, but the mere thought gave me chills and I always stopped them.
Is it safe to jump up and down while an elevator is in motion? Would the extra jolt of a 35 pound child hitting the floor pose a risk? What about an adult, say 180 pounds? I don’t know what the average weight is, so we’ll use 180 lbs.
I don’t know why, but all these years later I feel guilty for deriving my kids of this (possibly) safe pleasure.
I don’t know the engineering math exactly, but I would guess that if an elevator is meant to handle, say, a max limit of 4,000 pounds, then the up-and-down motion of a mere 180 pound adult isn’t going to exceed that. It would momentarily only be equivalent to, say, 500 pounds during the “down” jolt when the adult impacts the floor each time. Someone more knowledgeable can crunch the F=ma numbers for us.
But if you were to have a group of adults that weigh, say, a combined 3,000 pounds in total and they start jumping up and down - especially if in unison - then there’d be danger.
I think the 4k limit refers to how much weight the motor can handle. Those elevator cables can handle much more than that. It’s safe for anyone to jump in an elevator.
No, kid. It isn’t safe, if for no other reason than it isn’t polite to the other passengers. Just just fucking stand there until we all get to the floor we are going to.
Every elevator I have been in lately has had large signs posted that specifically say “Do not jump in elevator.” I doubt they would be there just because it isn’t polite.
I haven’t seen such signs and I doubt that the elevator is going to fall uncontrollably if you do jump. But what I can imagine might happen is the jumping triggering the safety mechanisms and putting it out of order until a mechanic is able to reset it.
I rode in a hotel elevator recently with my daughter and 60 lb grandson. I assume he thought it would be funny to unexpected jump up as the elevator was heading down. To all our surprise, the elevator stopped mid-floor with a jolt. The look on my grandson’s face was priceless. A moment or two later it continued down to the appropriate floor and opened up. I assume there is a motion sensor that senses when something unexpected like that occurs. This was in California so it may be an earthquake sensor. It’s safe to say my grandson isn’t likely to do that again in the near future.
Yes, I would only entertain this notion if we were alone on the elevator. Other people don’t need to witness the shenanigans, nor be terrified by the plummeting elevator.
I once spent some time stuck in a lift with a colleague who thought it would be fun to jump up and down inside. The thing didn’t break, but it detected a problem and emergency-stopped between floors. We had to call on the intercom - I think they knew exactly what had happened and as a result, left us to stew for quite a few minutes before starting it up again.
If I’m alone with my wife and or children and grandchildren in an elevator I do it. The key is to time it so as to jump just as the elevator descends; giving you extra hang time. It is fun, and I recommend it to everyone. For reference sake 200 pounds ish, and have never disabled an elevator doing this. I never jump repeatedly; it’s just one and done, once the elevator is in motion the thrill is lessened.
Safe and advisable are two different things.
Yes, it is completely safe. The failsafe mechanisms in modern elevators make it virtually impossible for an elevator to fall (thanks to Mr. Otis who did not invent the first elevator but the first elevator safety system). If a cable would break the car would immediately lock in place in the shaft.
Advisable, no. Jumping up and down in the cabin could set off e-stop sensors that would bring the elevator to a stop and you may be stuck there until who knows when a maintenance person can reset the system and get you out.
According to a few sources (including this one), elevator cables need to be strong enough to handle eleven times the load they are expected to see during normal service. To be clear, this is the weight of the entire elevator plus the people in it. According to this discussion, an elevator big enough for twelve people weighs about 2500 pounds when it’s empty. According to this PDF, 200 pounds is a reasonable estimate of adult weight for design purposes, so 12 people = 2400 pounds.
So if the total weight of a fully loaded 12-passenger elevator is about 4900 pounds, then the cables need to be rated for at least 53,900 pounds.
Let’s suppose all twelve adults jump up and down at the same time, as hard as they can. Maybe they’re athletes, and they can cope with 3 g’s on touch down (a total of 600 pounds per person), meaning they’ll be momentarily loading the elevator with 7200 pounds of force. Added to the 2500-pound elevator, that’s 9700 pounds. Remember, the cables can handle 53,900 pounds. So the safety factor is still 5.56.
A 35-pound kid doing 3 g’s when he touches down is only going to exert 105 pounds of force on the floor of the elevator. This is negligible. Do your worst, kid.
When I was in college our dorm elevator had an oddly springy cable system. If you bobbed your body up and down with the right frequency, you could get the elevator oscillating up and down with rather distressing amplitude. It would have been pretty much impossible for us to break the cables, because we would have needed to get it bouncing up and down so violently that it would be achieving 11 g’s as it bounced upward on the taut cables, and we would not have been able to remain standing for that - but I suspect it might have been possible to get so much slack during the ballistic upswing that one or more of the cables might have come off of its pulley. Maybe there was some kind of guide to prevent that from happening, not sure.
I now feel like I deprived my children of fun BUT I will tell them that they may safely jump, when I am not on the elevator with them. I don’t want to get stuck while waiting for maintenance.
Tell your kids that they need to bring water with them if they do so. There have been horror stories about people trapped in elevators on Friday afternoons with no maintenance and had to spend an entire weekend with no water until they were rescued on Monday.
One woman in China died after spending 3 weeks alone in a trapped elevator with no one noticing.
I have fond memories of making deliveries to the 41st floor of Big Pink in downtown Portland–we were required to use the freight elevator which usually had nobody else in it and was also a very fast elevator. Yes, I did the big leap Every. Fucking. Time. I don’t care if joyless poopyheads say I shouldn’t, I will always be an elevator jumper. I’ve jumped coming down from the top floor of the St Francis Hotel in San Francisco (outside glass elevators FTW!), I’ve jumped the elevator in the World Trade Center back when it still existed, I would have jumped in the Eiffel Tower elevator too but it was closed for repairs when I was there. Elevator jumpers unite! You have nothing to lose but your slavery to gravity!
Do most modern elevators use primarily cables or hydraulics? I would guess it would have something to do with the height of the building.
I was recently in a 7 story parking structure where the elevator shaft was visible from outside via windows. It functioned using a hydraulic lift similar to those in an auto mechanics garage.
This was back in college, so elevator technology may have changed. I, weighing 160 pounds, jumped. There were two other people in the car with me who did not jump. The elevator immediately stopped and we were stuck there until we pried the doors open and crawled out.
But don’t take my word for it. Let’s ask Big Elevator
A sudden jolt on the cables can activate the safety stop, protecting inhabitants from potential problems in the immediate future.
Quality Allied Elevators told CBC that elevators are designed to stop if a hop is detected for safety reasons. They state that if the car accelerates even a tiny bit, they halt the elevator to prevent any safety issues.
I used to love jumping in the elevator when I was a kid/teen (at the top or bottom of the ride). Maybe those older elevators didn’t have these sensors and/or I was light enough to not trigger them. I never had one stop because of it.
Older, heavier me doesn’t do much jumping anymore even if my inner child wants to.
According to this site, you rarely see them in buildings taller than six floors, and almost never more than eight floors.
No idea for sure, but I’d guess that most elevators these days are cable-hoisted. Manufacturers are already making all of the necessary parts for these elevators to go in tall buildings. ISTM it’d be cheaper to just make more of these for small buildings than it is to have a whole separate manufacturing process for hydraulic elevators.
Some advantages and disadvantages of hydraulic elevators:
