TechStuff Gets a Lift

probably is very familiar with them. Really, humanity has been pretty pretty familiar with these or at least some kind of hoisting device for recorded history. Yeah, pretty much. Yeah, because it turns out that we need to get stuff to places where that stuff isn't and sometimes that means lifting stuff up high places or up to high places and having someone carry it there is not always the most convenient method, right, So, so hoisting device ice has

been around for ages. There plenty of examples of various Pulley systems. In fact, Archimedes, which are longtime listeners, will know that that tech Stuff has done a podcast about our comedies. Our comedies was coming up with the first Winch and Pulley system, and by that I mean the winch, as in something that you wind the cable around and turned to to pull it up. Not not like a

bar far winch. Different, not a bunch of ladies carrying tankards and holding onto a rope and saying heave that would that would be amusing, but that's not how it works, um. Roman architect of Trivious reported that he that our commedies had built one of these systems around two d and thirty six b C. So that's the kind of time frame that we're looking at. And and there's definite evidence of Roman pulley elevators, you know, crude hoisting. I don't

want to say elevators because it's not really the right terminology. Sure, but a platform that can be hoisted up through a pulley system. Yes, we we're definitely used in the Colosseum to move gladiators and various animals that were trying to kill them. Not to mention to mention the idea of actually just constructing some of those massive stone structures that

you've seen. If you've if you've ever toured around Europe like places like Italy and you've seen these large buildings, you know that they're scaffolding and hoists and things of that nature that we're used to to lift stuff, so cranes, things like that. Well, all this is related to the idea of elevators as far as an elevator that was

used to like move people up and down floors. Uh, A predecessor for that still not really a true elevator, but a processor dates all the way back to seventy three a d in this case, and was called the flying chair. And it was this was this was King Louis, was right, Louis, You know stairs were for fools, said Louis. Supposedly this particular, this, this flying chair, this elevator was connecting his his his apartments to his mistress's apartments directly

right and uh. And it was mounted on the outside of his palace wall. So this was not some interior elevator. Rather, it was a chair he would sit in. He would go out to his balcony and say, you know, I'm want to pay a little visit to my Saturday night thing. And he jumped into the flying chair, although I guess he'd probably more very gently settle himself into the flying chair and signal for the servants to move the chair so that it would make the trip to the the

courtesan's room. And um, anyway, in this case, the the cables, all the stuff that would actually made the flying chair rise and descend were hidden by a chimney. So this is a chimney that wasn't designed to funnel smoke. It was just al the king, yes sort of, it was really it was really just to kind of house all the ropes and police. And there are counterweights as well to help balance this out. We'll explain why counterweights are

important later on the podcast. Counterweights or something that we find in modern day elevators. But the they also had servants in those chimneys that were that was their job to manually move the roop to so that the king could get to his appointment. And uh, yeah, that that

was a very early kind of example. But obviously not all of us have palaces to slap elevators on the outside of, right, It wouldn't be until until the eighteen hundreds that that further adventures and um, more public hoisting devices, right and and and what really made this necessary in a way, Well, first of all, we had a lot

of improvements. This is the industrial revolution that we're getting into, and uh, Some of those improvements included ways of producing stronger steel and iron, which meant that we had the potential to build very very tall buildings, which we could not do before. The materials we would use would would crack under the intense pressures the compression that they would

go under if you were to try and keep building upwards. Right, because previous to having steel skeletal structures inside buildings, they were all masonry frames, which means meant that they required thicker and thicker walls the taller that the building got. Um So you know, it's it's if you had something a grand total of something like seventeen stories on the ground floor, the walls would have to be six ft thick. Yeah,

and you know that's not it's not really sustainable. And in a large, large city population area, which was also happening, there were a lot more people moving to cities and land was becoming much more expensive throughout the course of the centuries, exactly. Yeah, you get you get these dense

urban areas, and so you have two choices. Really, you can sprawl, which is something we're very good at here in Atlanta, or you could build upward and then have people living in flats essentially, and uh and working in offices that were in high rises. And it was it was the the ads is in steel and iron production that would allow this to happen. But you still have

a problem. How do you get up and down from the floor you live or work on down to ground floor because after a few floors that becomes laborious after after you know, fifteen twenty floors. What's the quote from Ghostbusters like, let me know when we get to fifty, I think I'm gonna throw out something like that. Something

like that. Yeah, So one of the things that people were wanting to to explore was this idea of elevators, something that had a mechanical element that could lift a platform or lower a platform that people could safely people and stuff not just people but stuff as well could safely travel in that would get them to wherever they needed to go within the building. Um vertically, that is,

we're not talking about woncovadors. I joked with Lauren before we decided to actually do this podcast that we should cover woncovaders, But of course those are magical, so they don't really count in text stuff. Sometimes in the eighteen twenties, Paintern and architect for the names of Thomas Horner and Decimus Burton, and I kind of just wanted to make this note because Decimus it's such a great name. Come

back anyway. They collaborated on what was called an Ascending Room in London, which which hoisted tourists thirty seven meters high. Thirty seven meters that's pretty high. It's not too bad. That's that's that's a that's a good. That's a good. Yeah, you're talking like nine floors. That's that's significant for for the eighteen twenties um to view the London skyline nice. And then by eighteen thirty five in Great Britain they were already starting to use elevators that had belt driven sheaves.

No One a sheave is is it's a special type of pulley. It's a it's a pulley that has that has grooves on the circumference yea, so it allows it to grip onto the rope or cable so that it can use traction to to actually move that rope or cable.

You turn, you you move the elevator by turning the sheave, which then pulls the cables as opposed to you know, if you think of a traditional pulley, Usually there's a weight on one side and then you're holding the rope on the other and when you pull down the rope, the weight goes up because the pulley rolls and allows the rope to move. Right. In this case, you've got a pulley system that's actually gripping that rope. So when you turn the pulley, it moves the rope itself. It

does some of the work for you. Yeah. Yeah, that's the important part, because otherwise you'd have to always have some sort of external motor that was holding onto the case, using a lot of energy to to hold that exactly right. So so they had started doing that in eighteen thirty five, and they also used counterweights. The counterweights helped provide the friction that traction necessary for the sheave to grip onto the cable and also made it easier for the elevator

to move up and down. And again we'll explain more about that in a little bit um, but then moving ahead. So this is still the very earliest days of elevators. By eight the eighteen fifties they started to see steam and hydraulic elevators, but they generally weren't used for passengers because there was always the potential that the elevator could fail, and there weren't any safety measures really in place that could prevent an elevator from just plunging after a failure.

But that was coming up very soon. Yeah, by eighteen fifty two, in fact, when the name in elevators, UH created an innovation that would allow passengers safe elevators to become a thing, and this was the safety break right, invented by Elisha Graves Otis. So the Otis elevator. If you've ever been in an elevator, there's especially in the United States, there's a really really good chance you saw

the name Otis on the elevator somewhere. It's not to say that that's the only company that makes elevators, but it's it's a it is a big one and probably the best known name, at least in the United States now. In eighteen fifty two, that's when Otis invented the safety break UH. And it was technically a latch, a safety latch that would allow the elevator to remain in position if the lift system failed. So, in other words, if

the cable that was holding the elevator snapped. Uh, this safety latch would ratchet in on racks on the side of the elevator shaft, inside the shaft right into ah. Yeah, yeah, you had like the spring loaded essentially a spring loaded uh latch, and once the the support system would break, it would spring out and catch on one of these racks and the elevator would stop falling. And uh. He he was actually designing this, not for an elevator for people.

He was working for a company. It was a betting factory, and the betting factory it needed to find a way of lifting equipment safely up into the factory floors. And so he came up with this idea and then realized, wait a minute, this this is great for all elevators. Yeah, this could work for well beyond just this one application.

And so, uh, specifically, the little um bolts that it used, they're they're called Poll's p a w l s. That's technically any sort of sliding bolt that's designed to fit into something into notches usually and uh, and at first he was he decided that he was going to go into the elevator business pretty early on. By eighteen fifty three, he started a company that would eventually become the Otis

Elevator Company. Uh. And he sold a grand total of three whole elevators in the United States, and each one he sold for about three hundred bucks, which at the time wasn't bad. But but but three of them, Yeah, it's less than promising. However, that that is why the next year, in eighteen fifty four, he decided to demonstrate this technology publicly at the World's Fair. Yeah. In fact,

that was that was his brilliant idea. He said, you know, I made three sales and then nothing like the Keep in mind this is still early early days for tall buildings too, so there there wasn't yet a huge demand for elevators. And so he was kind of I hate to use this phrase, but I'm going to now anyway,

he was getting in on the ground floor. And so yeah, he decided he'd go to the World's Fair at the Crystal Palace Exposition Center in New York City and publicly demonstrate how his safety measure would keep elevators safe even in the case of a catastrophic failure. And I read an account of this and it was pretty interesting. He had set up a little uh a demonstration elevator shaft, uh, and it was really just the side walls to the shaft what would be on the sides of the elevator shaft.

There's no front, no back, so it gave a clear view, all right. He had the platform which served as what would be a full elevator, but there were no walls to the elevator either. It's just a flat stage really, And then there was a rope that hoisted the stage up to the top of the as far up on the shaft as it could go without falling off the guide rails. And then he got everyone's attention and cut

the rope. The shaft fell about a foot or so and then caught onto the ratchet ratcheted notches that were on the sides of the shaft, and the elevator was sturdy. It stayed there and and he proved that it worked. And he did this demonstration multiple times. It wasn't just the one time, but um that ended up being an

incredibly effective demonstration. People began to see that there was promise in this that uh, that the safety measures would be effective, and so they started to really think about using elevators to help make high rises a possibility to keep in mind if this had not worked, If if he had not done this, the development of the high rise type city would have been held off for how many years I'm sure we would be there by now.

One else would have come up with the idea. Yeah, but just imagine how different our cities would look because buildings that were built early in that phase would not have been built. They would have been put off, which means that you'd have a totally different kind of architectural style in place by the time that they were being built. So do you think about it. The elevator is why some of our most famous cities look the way they do. It's kind of cool to think of it that way.

It's it's all. It's all. Yeah. The conflagration of of that and property values and steel frames, yeah yeah. The fact that all these things were working together at the same time. It was just very fortuitous, especially for otis Uh. In eighteen fifty seven, he then installed the first passenger safe elevator in a New York department store called and I'm no, I'm gonna get this one messed up? E V how what and company? This? This was a five story department store YEP and the elevator could rise at

the mercurial speed of forty per minute. Now keep in mind in general ten feet that's about on story, so that means it could go at four floors in one minute. I thought our elevators were slow, But that would be that would be a leisurely elevator ride, if you were going from the ground floor to the top floor. That would But if but if it's the first elevator you've ever been in, that possibly anyone has ever been, might been gripping onto the side in terror for fear of

how fast it was moving. Yeah, yeah, I guess so. Uh. And then in eighteen sixty one, Otis dies from diphtheria because even though his elevators wouldn't fall, he fell ill. Jonathan wrote that in the notes and I and I've already groaned and shaken my head at it at an earlier point today. And then she was wondering if I would actually read it, and oh no, oh, no, I knew you. Yeah, you've worked with me long enough now

on April. He died on April eighth, and that was just a few months after he had been granted a patent for his invention. Now keep in mind you know, you file a patent and it can take several years from the time you file it to the time it's approved, right, I think he had He had applied for it a full ten years previous to that in UH in eighteen six No, so it was nine nine years, just just under a decade, and he got that patent granted UH

in January of eighteen sixty one. So he he did live to see his invention patented, but not long after that he fell ill from diphtheria, which there wasn't dip Theoria epidemic at the time. He died in Yonkers, New York, and his his sons, however, h survived and one of them, Charles Otis, was known as being the businessman in the family. He had a very keen I for business, and so they took over the company and UH and they continued to run the company and they were very successful in

eighteen seventy three. By eighteen seventy three, so this is just a little over a decade after Otis had passed away, the Otis Company had sold over two thousand l of leaders working in places like offices, hotels, and department stores. And then by eight eighty that's when a fellow, a German by the name of Furner Vaughan Siemens, is the first to actually use an electric motor in elevator construction. And his version was really interesting. It didn't involve cables.

You know, most most motors involve pulling some sort of cable system to raise or lower an elevator. They're usually they're usually working directly on that sheaf that we were mentioning, right. Instead, what this one did was it had pinion gears that engaged racks on either side of the elevator shaft and literally the gears would yeah, yeah, exactly. So it's kind of like think of it like a locomotive, but going

vertical instead of horizontal. But but of course you have to have those pinion gears because otherwise you don't have enough traction to make the elevator go up. Um. But yeah, that was that was the first u of it. Now, later we would see the electric motor. In fact, shortly later there would be electric motors that would actually use more traditional cable systems. Um. But that was the earliest uh use that I could find for an electric motor. Ye, all the all the other motors up to this point

where being run by steam. Yeah, they had steam powered and hydraulic powered and hydraulics and that was it. That was it until eighteen eighty. By eight the Otis Company had merged with fourteen other elevator companies to become the Otis Elevator Company. So Otis was not the only name in the elevator business at that time, but once it merged with these other fourteen companies, that became probably I would say, the most uh prevalent, most powerful elevator company

in the United States easily. This was this was around the era when when Steele was really really taking off and um and the the the last of the big masonry frame buildings had were we're being completed at the time, everything new that was starting out was all steals. So it was a huge business. Yeah yeah, and it ended up being uh. While the elevator industry in general, just like the joke I said at the top, it did have its ups and downs. It's is both both true

and funny. Um uh. You know, because there was this ongoing trend to taller buildings. Anyone who was in the industry knew that there was a future in it. It wasn't. It wasn't like suddenly people weren't going to want elevators anymore unless they decided that they no longer wanted to have tall buildings and would rather sprawl out again. And that just didn't seem like that was ever going to come to be an option. So uh, really, that's the

basic of the timeline. I mean, of course, lots of advances have happened since then, but that we just wanted to kind of cover the sort of the history of the origin, the origin of elevators and then go into more about how they actually work. And the first one we wanted to talk about, we're elevators that use and that are elevators really because there's still are elevators that do this that use hydraulic lift systems. They aren't using cables at all, so and yeah, yeah, so so there

there are two basic systems, hydraulic and cables. And and yes, hydraulics are slightly less common for several reasons that were that we will get into in a moment. Right, So, if you have a shorter type of building, like to two to five story, I would say maybe even two to four hydraulic elevators may be something that you've experienced, because um, I mean I actually knew. I used to one of the libraries I used to go to as a kid had a hydraulic elevator. Um. And the way

these work is beneath the bottom floor. So you've got the you know, the ground floor where the elevator comes down to a stop. That's its final stop. It can't go any lower and dug down Beneath that, yeah, is your hydraulic system. And that system consists of there's a cylinder. Inside that cylinder is a piston that has the hydraulic ram at the end of it that connects directly to the bottom of the elevator. And then you the connected to that cylinder is a holding tank that holds all

the hydraulic fluid. That has a very powerful pump that can pump fluid from the hydraulic tank into the cylinder. And then there's also a return valve that when it's closed, won't allow hydraulic fluid back in, but when you open it, it does allow hydraulic fluid to move from the cylinder back into the holding tank. Now, this is a closed system that means that that hydraulic fluid is either going to be in the tank or in the cylinder, or there's gonna be some mix of you moving in between

the two. Right. But they but you don't lose hydraulic fluid, assuming that there are no leaks. So uh, it means that you can reuse that fluid over and over and over and over again. So that's one reason why it's popular. Um. So, the way it works is that you turn Let's say that you're on the ground floor and you hit two, you want to go up to the second floor. What happens is that sends a signal to the hydraulic system

beneath the elevator. Uh, turns on the pump that then starts to pump hydraulic fluid from the holding tank into the cylinder. Right that the fluid pushes on the hydraulic ram or piston and moves it up the shaft. That's right. It displaces the piston from the cylinder. So, depending on how tall your building is, it may have to pump more or less fluid into you know, whatever floor you've pressed.

So if it's a four story building and you've hit four, it obviously needs to pump in enough fluid to get to lift the ram all the way up to the fourth floor. Uh. And then when you're coming down, the valve opens up and allows fluid fluid to come back into the holding tank and just basically let's gravity pull the car back right and you control the descent by

the aperture of the valve. I mean, obviously, if you if you were to open the valve all the way up and it was a large valve, then that elevator could descend at an alarming rate. But it's usually a pretty a pretty tight system. So so it's usually it's usually the pressure of the fluid and hence hydraulics that are allowing it to you ease gently back down to

exactly ground exactly or whatever, right exactly. Uh, it's it's very you know, like I said, I've written in these kind of systems before, and uh, it's a gradual ride. It's it's um But I mean it was a library in rural Georgia. You know, most of the people going to this were in their latent four hundreds, so you know, they don't need something that's going to be an exciting ride up and down the side of a glass high rise in Atlanta. All right. The speed is one issue um,

they are slower. And the thing with that, with that piston system is that you have to dig the further up the piston is going to push, it needs to be at least that long going down into the ground. Exactly. Yeah, So if you're telling four stories up, you have to dig far enough down so that that piston, when it's completely retracted, fits right about four stories into the ground. Yeah exactly. And then when it's fully extended, that means that the whole system is eight stories all because you

have to have you know, these pistons don't retract. It's not like they are kind of collapsible telescope. No, it's not, yeah, exactly, it's it's a solid piece. And so uh yeah, if you want to have a forty story building, that would mean that you'd have to have a piston that was incredibly long and you'd have to dig really far down.

It's just not practical. So so that's uncommon. Uh, And you normally run into rope or cable systems are often that the names are interchangeable because when they're talking about ropes are talking about steel ropes, and we will explain exactly how those work in just a moment. But before we do, let's take a quick break and we're back, all right, So let's talk about cable or rope system elevators.

These are probably, I would say, these are the most common types of elevators that you're going to find, definitely, and uh, and they do they rely on what it sounds like, they rely on cables or ropes steel ropes. Right.

Right now, You've got these these traction steel ropes that are going to be attached on one end to the elevator car then go loop up around a sheave, right, which is that that pulley that has those grooves in it that allow it to grip onto the rope or cable right and then attach at the other end to um to a counterweight, right. And the reason for the counterweight again is to kind of make the whole system

work more easily. Here's the idea. Your counterweight typically weighs about the same as the elevator when it's at capacity, so a little less than a half full elevator. And the reason for that is that when the sheaves starts to turn, it has to do less work if the

counterweight and the elevator are close to the same weight. So, uh, you know, you would imagine that if it were just a shave and there was no counterweight there, it would have to turn the turning power that torque that has a lot harder, And this way it just has to overcome a little bit of friction. And then let's the

weight actually do most of the work. Yeah, and if not most of the work, Let's say you've got a full elevator and obviously a capacity thing wouldn't wouldn't outweigh the full elevator at least offsets some of the power needed so that torque that has to generate doesn't have to be as great. And this is important so that you can just make it an efficient system. Uh. The counterweight also helps with some of the safety features as well, though it can also be a hazard. We'll get into

all of that towards the very end. So trickle way for us to end the podcast. Actually, now that I look at how I laid out my notes and thinking, all right, so so so so the sheave is connected directly to sometimes directly to a motor. And there there are two kinds of these cable system to basic kinds of these cable systems gearless elevators and geared elevators and the gearless ones. The motor um rotates the sheaf directly, and in the gear list it's connected to a gear train.

Right the geared ones, it's just a series of gears that connect the motor to the sheave so that it can translate rotational motion to the sheave and allow you to pull those ropes and move the elevator up and down. Now, a typical elevator, these are not they're not all like this, but the typical elevator will have that sheave at the top of the elevator shaft, all right. So at the very top of the elevator shaft is this this grooved

pulley that is motorized. So the pulley itself is the thing that it turns and moves the elevator up and down. You've got the counterweight that is connected to one end of the cables. That not only provides the ability for the sheave to do work without having to exert more energy, but it also creates that tension, that that traction or friction that it needs in order to move the cable that holds the court taut against the sheaf, right, and that and that's why the sheaf. When it turns, the

cable itself moves. Otherwise it could just slip against the cable. That would obviously be dangerous and it wouldn't or best case scenario, your elevator doesn't go anywhere, it's just spinning. The sheet would just be spinning against the cable. Worst case scenario, it could cause a terrible accident. Uh. There By the way, multiple cables connected between the elevator and the counterweight going around the sheave. It's not like there's

just one. It's not like in the movies where where you know, like one little metal thing kind of snaps and then all of a sudden an elevator goes plummeting. There's usually seven or eight of these things and very strong. Still, Like one of these cables would be capable of holding up the elevator, but there's seven or eight backups, right, yeah, they the idea of being usually I think the fewest I've ever seen was four. So between four and eight

cables is typical. And like you said, Lauren, each one of these would be more than capable of holding up the elevator in its own You have that those others for redundancy because obviously you don't want to have your elevator be unsafe. So so so yeah, so so, the the sheave and the motor usually UM contained in a compartment above the elevator or sometimes on the side. Occasionally there will be cabinets on the side and UM and the sheave will be on the side there and moving

everything along that way. That it's it's a little bit more complicated. But yeah, I've seen like the simplest one has the sheave mounted to the elevator shaft and it's completely separate from the elevator. But there are elevators that have motors that are connected to the elevator itself, not to a not to something that's mounted on the shaft.

It still works on the same principle, right, It's still got this rotating sheave that is moving the cable through, but you've just located the sheave on a different part of the system. So instead of it being part of the building, it's part of the elevator. Isn't isn't the Marriott in downtown Atlanta? Um? It could be. I feel like I could be completely lying, folks. I have no idea. Yeah, we've got a lot of fancy elevator systems down in Atlanta.

For example, if you ever are in Atlanta and you want to have a real treat, you go to the UH Peachtree Tower and you ride the glass elevator all the way up, which is on mounted on the side of the building, so you actually have a view of the outside of Atlanta, and ride that all the way up to the rotating restaurant called the sun Dial at the very top of the Peach Tree Towers high. I don't know the two floors which is personally comfortable with that.

I'm sure many of our listeners live in cities where seventy two floors is not But for Atlanta, that's pretty tall. Yeah, and it's an exciting right, I gotta say I've I've gone up there many times. Um. But yeah, So so we've got We've covered the counterweight, We've covered the sheaveh We've covered the fact that we use the counterweight to help conserve energy and with the idea of the potential energy. These elevators also have lots and lots of safety features.

Oh and before I mentioned going to safety features, I should also mention the elevator car and the counterweight ride on guide rails very important. The rails are what keep them from swaying when they're going up and down the shaft, which anyone could tell you is a good thing, right absolutely, and it also helps out with some of those safety features that we're going to talk out talk about in a second. Yeah. In fact, let's just go ahead and segue into that, because you know, we need to talk

about the sort of things that keep elevators safe. That was you know, the little opinion system that OTIS came up with, little system the thing that made elevators possible. That that was one element that was elevator safety. But of course when we're talking about uh, elevator systems that can go all the way up to over seventy floors, then you want lots of different safety features there, you know, lots of redundancy, not just uh some some little palls and some racks that are on the side of the

elevator shaft. Right right, Yeah, that's that's okay for five stories, but I'm less trustful of it first saying, you know, a hundred um so so. So the main kind of system that we're working with here is is called a governor system. Yeah, and it's uh, I was very disappointed to find out that it wasn't like a cockney thing so we could like the governor. The governor, Um, no, it's and by the way, I did a little arm thing that you know, you guys don't get the benefit of.

But I think if you say governor, you have to do a little like a little little swing your arm. Just a governor. Um, sorry, all my friends in the UK, former friends in the UK. So the governor is is a safety feature that is supposed to help prevent the elevator from moving to quickly. And it's it's literally springs into place if it does move too quickly. Right, this

is a this is a second rope system. There's there's a rope um it's it's looped around the governor sheave at the top of the shaft, and then another weighted sheaf at the bottom. Right. So in this case you've got the main set of ropes or cables that are attached to the counterweight and to the elevator which move the elevator itself and the elevator sheaf, and then there's a secondary sheave and cable system that's the governor sheaf.

This is completely separate. It is connected to that main sheaf, but but it is attached to the elevator. It's got these two sheaves, one on the top, one at the bottom, and then is connected in the middle to the elevator, so that when the elevator moves, this rope moves in between the two sheaves. Right, the governor sheave is actually has flyweights. These are these weights that are held in

place by a high tension spring. They pivot on pins inside the sheave and uh and and are attached to each other so that they're not because they've got little hooks on the ends. Right, they've got the teeth so that it actually hooks into notches that are on the inside of the governor sheaf. Okay, so the governor sheaf has these notches that are stationary. They do not turn with the rest of the sheep. The fly flyweights do turn with the rest of the sheep. Now, there's a

tension spring that holds those flyweights in place. But if the faster that the that the governor sheaf is turning, the stretchier the spring gets right because of centrifugal force. Correct, So as the centrifugal force gets strong enough, if it's if it's spinning fast enough for the centrifugal force to to counteract the tension on the spring. Those flyweights spring out and then they catch on those ratchets on the inside of the sheet, which again are stationary. The inside

the sheave is not turning. It's the outside that's turning in these fly weights that are turning, and so the fly weights will hook into it and stop the governor sheave, which will stop the rope, which will stop the elevator. Connor, Yeah, it's it's um. Usually it also enacts a breaking system, so it's not like it just jerks to a halt, but it does, in our enact a breaking system that will make the elevator slow down and then ultimately stop. And this is you know, necessary for any elevator system

where you're going more than a floor. So obviously the higher up you are, interestingly enough, the more uh likely the system will kick into place, because your elevator will be accelerating at the speed of that while the accelerati of speed of gravity and uh, assuming there's nothing else holding it back that's slowing it down, so it actually will be more likely to to to activate the further up you are. UM kind of a terrifying thought, but

it is true. Another part of the safety system is, just like you said, Lauren, just the ropes themselves, because they are all so strong. They're made out of steel material, they're wound around. It's kind of braided in a way, braided steel and uh. And like we said, one rope can support the weight of an elevator, a full elevator, but they usually have between four and eight so that you don't have to worry so much. If one rope snaps,

the others can hold on just as well. And then you've got some electro magnetic brakes that are supposed to pop into place if the elevator exceeds a certain speed. Right, the electromagnets under normal circumstances hold the brakes open, and then if something terrible happens, they snap those brakes down. Right. So these are all the different systems. And then there's the there's the final uh safety measure in an elevator

system that's common amongst most elevators. All else fails, and the and the elevator car does fall down the shaft, there's usually something at the bottom that's going to help cushion that fall, right, there's usually some sort of shock absorbent system. It might be a fluid filled system where it's like a again like a cylinder with a piston with oil in it, so that uh, the oil in the cylinder and then as the elevator makes contact, it compresses.

It could be a spring system. It could be essentially what amounts to an elevator style crash pad. Right, It all depends on the actual system. But these are you know, some sort of shock absorber that will you if you've ever seen a seen an open elevator shaft, I mean, don't go looking for this, but you know, if you've ever seen a seen the elevator doors open on the ground floor and you see some kind of large cylinder sort of thing, that's that's what that is. Yeah, Yeah,

so that covers the the safety. Uh, we didn't really talk so much about the doors. The doors do usually have some sort of automatic system so that if it detects that there is an obstruction, they will open automatically. That's what's supposed to happen. We'll get into whatppens when that doesn't happen in a minute. Um. And then there's also the whole idea about selecting your floor. Now, back in the old days, right, right, you had to have

an elevator technician bell hop. Yeah, yeah, the I know there's I know that there's a specific term and I can't come up with it either, but yes, you have an elevator attendant essentially. But the elevator attendance job would be you would walk in and you know, you've probably seen these in movies as someone who's dressed up in the fancy outfits this what floor, and then you tell the person and they make sure that the elevator doors

are closed. Usually in these systems, the elevator was designed so that it would not work unless the doors were closed. It's not true in the case of every elevator, but it was one of those safety features, right. And those those original elevators had had two sets of doors. They had interior doors attached to the cab to to the car of the elevator that um that would that would lock into place, or that the that the cabby would would look into place. And then the exterior doors were

opper rated external externally. Yeah, you had to have the external door so that people wouldn't just wander up and fall down an elevator shaft, which has happened and I'll cover that, but they were all manual, right yeah, so, um, so what would happen is you would tell the elevator operator where you wanted to go, like what floor you wanted to go on, and then they would hit a switch which would essentially be climb or descend, and then once you got to the place that you were going,

they would turn it off and you would get off the elevator. And a good elevator operator would be able to stop the elevator. So we was right there at the floor and you didn't have like a list step up and down, yeah, which could cause problems. You could you could trip and fall or something. Um. Now, of course, these days we have computer systems that automate all this where you've got a panel of lights or sorry, go ahead, yeah, I'm sorry. Yeah, you were you were talking about the

external That's completely right, Lauren, I was. I was talking about buttons because I think buttons light up. But you know the button, when you press a button, it tells essentially sends a signal saying that this elevator needs to go to this floor. How does the computer know what floor the elevators already on Lauren. Huh uh. That that is done by a series of of of lights or magnets or other indicators along the wall of a shaft, and as the as the elevator car moves past them,

the computer takes note of where it is. Right, So essentially the computer is counting what floors you are on, and that's how it senses it. Now, you can get into more advanced sensors these days, but that's that's sort of the classic way, right, So uh yeah, it's it's pretty simple stuff. You know, you hit a button and it just sends a signal saying this elevator needs to go to this floor, and the mechanics do the rest once the computer has processed that request. And there's a

couple different levels of computer sophistication that are involved. The classic ones will just go up until no one has pressed up anymore, and then we'll start to collect the

down calls again. Right. In other words, if you've got, uh, if you've got three people in the elevator, someone's hit to, someone's hit four, someone's hit eight, But there's someone on floor seven who wants to go down, that elevator is not going to stop for the person on seven until it's let off the person from eight uh and and there's there's lots of newer systems coming out that that will assess traffic patterns and send alternate elevators to alternate

floors at different times of the day, depending on who needs to go where it's It can get a lot more complicated than that. So for example, here in the building we work in in the morning, there's almost always at least one elevator at the ground floor already because not enough people have arrived for those elevators to be used in between floors. Right, it's usually ground floor to whatever your destination is, and if it's early enough, it's

only people coming in and small groups. So you walk in and you press the button and immediately a door opens. It feels like it's magic. Sometimes there's already a door open before you even get in there. There have been times where I've walked in no doors have been open. Before I can even hit the button, it goes bing and I think that's security, just do that for me, But um or are they watching me? I don't know.

But either way, they have been more sophisticated and in fact they've even gotten so sophisticated, as in some buildings that have lots and lots and lots of floors. Instead of just hitting up or down, you actually end up indicating what floor you're going to floor, and then and then you're told which elevator to go wait in front of,

and then it'll take you to your floor. Um. There are plenty of buildings I've worked in that had express versions of this, where it just gave you a block of floors that the elevator could serve, and it was it would skip all the other floors, which, if it's high enough, means it's almost guaranteed to make your ears

go pop. Yeah, yeah, it's always fun. All right. So let's talk about elevator accidents, which I had not planned on talking about, but I sent out the message on Twitter before we record this podcast and receive a request from Nannie, and Nannie says, always see elevators crashing on TV and movies. Has it ever happened in real life? The ord answer is yes, it has a lot. Not a lot. Let's not say a lot, Laurence. We work in a building where there's an elevator, it doesn't happen

a lot. It has happened over the course of history. It's happened a few times, right now. Let me there's a lot of news stories about it. They're kind of gruesome that the stories are awful, which make it seem like a like a lot um and and and even you could argue one time is too many, and I would not argue against that, because obviously you're talking about people's lives, and I treat that very seriously. But no, no, I mean, in the grand scheme of the universe, a

very few elevator accidents happen these days. Yeah, let me give you a statistic. According to the U. S. Bureau of Labor Statistics and the Consumer Product Safety Commission, the

estimate is that elevator accidents caused twenty seven deaths per year. However, elevators make about eighteen billion passenger trips per year, So out of eighteen billion trips of taking people up and down floors, seven people die, and out of those number the most The most frequent victims of elevator accidents are maintenance workers, people who are working in elevator shafts to fix it right, and someone has failed to enact the proper safety features to prevent an elevator from moving up

and down while the maintenance work is being done. That's tragic, but that does seem to happen the most frequently. Behind that behind maintenance workers are people who, for some reason or other choose to get out of an elevator car while it's in a shaft and either in an attempt to escape a car that has been stuck, or to do something like elevator surfing, which is an incredibly stupid thing to do. You do, do not do just because you see that happening like die Hard does not mean

that it's a good idea. No, don't do it. It's it's almost it's almost a guarantee for severe injury, if not death. Don't do it. Uh. Elevators in reality do not work the way you see them in movies. The elevator chefs are dark, they're nasty. Everything is covered in in in oil and grease because it has to be lubricated to allow elevators to pass and uh, and they cramped the same the same way that air events do

not perfectly fit a human person or two human people. Yeah, I was very disappointed to find that air events don't come in Bruce Willis size, like it's not just a standard. Um, it was very disappointing to me. Yeah, the same same principles. Elevator chefs are not fun places to hang out. Yeah. So, um, let's talk a little bit about some actual accidents, right, yeah, and and so so so so some some of these accidents are caused by the way that the doors work

in modern elevators. Um, there's usually a motion sensor that prevents them from closing if someone is standing in the way. I'm sure that you've seen that. And I want to mention before we really get into this, some of these descriptions could turn out to be a bit gruesome. So if that is something that does bother you, I would completely understand if you end listening to the podcast right now and wait for our next episode, where we'll probably

talk about puppies. But um, because I'm gonna need something after this people. But yeah, maybe we'll talk about some of those robotic dogs or something. But but yes, we are going to talk about some some fairly famous accidents and uh and not and and they're they're not they're not pleased. I've actually got them by chronological order. So before we get into any other ones, specifically about the doors. All right, so we're back. Uh. This is not the

first time there was an elevator accident. It's just the first one that I took a I listed. UM, I did a kind of a search for elevator accidents in general, and then picked a few. In eighteen nine, U. S. Congressman Isaac Jordan's died after he stepped into an open elevator shaft. What had happened was he had called an elevator. UH. He was talking with a friend of his when the doors had opened the elevator. He essentially spent too long

speaking to his friend. The elevator then moved changed floors, but the doors failed to close, and so the Congressman Jordan's, upon concluding his conversation with his friends, stepped back into what he thought was the elevator but was in fact an open elevator shaft, and he fell to his death. UH.

Nineteen o three in Pittsburgh, Pennsylvania. Uh, this was one of those cases where it was UM, the the accident was was due to the behavior of the passengers, because not in not every case is it's something where there's a mechanical failure. Because the elevator itself was poorly maintained.

In this case, there was a big conference that was going on in Pittsburgh, and uh, there were all these people in this one building and seventeen of them crowded into an elevator that was designed to carry at maximum like ten people. Seventeen people crowded into this elevator and in the Donnelly Building in Pittsburgh, Pennsylvania, and the elevator fell six stories and then the cable and assembly fell

on top of the elevator. Yeah, because it was it was too much weight, and it pulled the whole thing down. Four people out of the seventeen died, so the others survived, injured, but they were survived. They survived. And again the accident was blamed on the fact that too many people crowded

into the elevator at once. And this is part of why there are floor sensors and most elevators these days, which we'll we'll do that really high pitched annoying dinging thing if you or buzz or whatever when you load too many people onto an elevator and telling you to get some that weight out of there because it is too much, right, and and the elevators these days, almost all the ones that have this system, and that's they will, right. And I've I've been in elevators that have done that.

I mean, while while we're on this topic, I just wanted to mention I kind of meant to mention it back when we were talking about computers. But um, but when you if you're trying really hard to get somewhere on an elevator and the eleva leaders are very busy, only press the direction that you want to go. Because the computer systems actually pretty advanced. It knows what it's doing and it can do its job better if you tell it what you need. Don't here, don't here, don't

keep both up and down if you're playing on going up. Correct. I had to have a little levity in there because some of the other accidents are just so awful. Here's here's one that's a remarkable story and remarkable for multiple reasons.

It's both awful and amazing at the same time. Um. That was the year when a bent Fi bomber flown by Lieutenant Colonel William Franklin Smith Jr. Uh was flying through a heavy fog bank missed the airport landing strip, and instead crashed into the north face of the Empire State Building. Goodness, yeah, not many people know about this accident compared to uh, the the the terrorist attack on nine eleven, which obviously there are parallels, right, but this

was this was an aviation accident. It wasn't done, it wasn't a purposeful attack. But yes, it slammed into the north side of the Empire State Building and among the people who were injured was a woman named Betty Lou Oliver who was an elevator attendant and she was on the seventy five floor at the time. She was knocked down and she was burned by jet fuel essentially airplane fuel, and so firefighters were able to put the fire out

in about forty minutes. I think it was the highest fire any firefighters have been able to uh to extinguish. And then the rescuers they found Oliver and they knew that they needed to get her to an ambulance, so they put her in an elevator, but that elevator had been weakened. The elevator doors closed, and then the cable snapped and the elevator plummeted seventy five floors, landed on the crash pad, then the assembly and cable hit on

top of it. She survived, They pulled her out of the rubble she was, she survived and they were able to get her to the hospital. Yeah. Pretty insane at any rate. So these were all early accidents, uh, and

accidents still happen. Part of the reason why a lot of the safety features that exist today have been put into place, right exactly that these accidents showed that there were other safety measures that needed to be there, and once in a while, uh rarely an accident still happens, maybe you know, involving the elevator doors or some other system. But the important thing to remember is that uh that you know, eighteen billion trips is that's a lot of trips,

and so they are phenomenally safe. It's just that when you hear about the accidents, they seem they seem, uh, they capture our imagination, right, It's I mean, it's it's one of those things that that can easily overwhelm a person and you can start concentrating on it too much. It's kind of like getting into a plane, this this

idea that you're giving up control. Um, But but we should you know, I definitely want to stress that the elevators that are in use today, especially the ones that are in public buildings where they have to undergo regular uh investigations, a regular regular maintenance and share checkups, you know,

all of that sort of stuff, are remarkably safe. Yes, and and also furthermore, um, the lessons that we can take away from from some of the things that we did not mention that have happened more recently are just that if you if you are stuck in an elevator, I myself been stuck in an elevator for not too long, maybe half an hour or so. Um. If if that happens, you know, don't don't panic. There's usually call box in there.

Use that. Also, don't try to pry open the doors yourself, and and don't try to uh to leap dramatically action hero style out of the elevator if it if it seems like bad things are happening, probably bad things are not happening, And you have more likelihood of um, of getting caught in in a door mechanism and injured that way than you do of the elevator actually falling right. Yeah, it's um, you know, it's it's definitely one of those things where a lot of the deaths and injuries could

be avoided if people follow the proper safety protocols. Uh, specifically with the maintenance workers. Um, it's you know, it's it's it's technology. Sometimes technology fails, but but I would say that it's one of the most reliable ones that

we have out there. Uh. And of course, remember where humans really bad at factoring in odds, So things like, you know, the odds of of operating a vehicle safely are actually worse than the odds of having a safe flying and which are you know, the same like taking an elevator ride safely. So I don't want to make everyone feel like they have to the stairs from here

on out. That's not the case. It's very healthy. It can be unless you're at the top of the seventieth floor, in which case you kind of have to pack a lunch. But you know, it's it's definitely that's not the message that we're trying to send here. Certainly not all right, Well, uh, thank you for that question, nanny. You've taught me a

valuable lesson, and that is not googling elevator accidents. No, I read way more than what I described, and uh, and and yeah, it's there's no point in going over it. These are all the exceptions, and uh, there's nothing but just it's just disturbing. But it turns out again like these are all exceptions, not the rule. So um, yeah,

don't be terrified. All right, I'm glad that I've stressed that. Now, Guys, if you have any questions, any comments, any suggestions for future episodes of tech Stuff, I highly recommend you get intest with us and let us know because it's kind of how we choose these things. Send us an email our addresses tech stuff at Discovery dot com, or drop us the line on Facebook or Twitter or handle up. Both of those is text stuff H. S. W And Lauren and I will tell you again really soon for

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