How do elevators work?
Elevators are like magic. You walk in, the door shuts and when it opens again, you are suddenly someplace new! Ta da! But it’s not magic that does this trick, it’s science and engineering.
In this episode we explain how elevators work and we talk about how they’ve changed over time. For instance, did you know the first elevators had no walls?
We also speak with historian Lee Gray about two elevator innovators who both happen to be named Otis. Speaking of Otis, Vijay Jayachandran with the Otis Elevator company, joins us to drop some high level elevator facts. Plus, we hear your ideas for the elevators of the future! And listen to the end to our Moment of Um for an answer to this question: Why do crickets chirp?
Want to keep learning after the episode? Sign up for our newsletter to get recommendations for books and experiments you can do at home.The Tale Of Two Otises
Elevators seem like an obvious invention when you think about it. Buildings are tall, stairs take forever and people wanted an easier way up. So, someone dreamed up the elevator and then everything was better.
In reality, it took many people hundreds of years to perfect this technology. Still, there are two main figures who really helped shape the modern elevator, and both happened to be named Otis.
One was Elisha Otis, a sharp-witted tinkerer who founded the business that would become the Otis Elevator Company. The other was an inventor and dreamer type named Otis Tufts who made people actually want to ride an elevator. Even though these two Otises shared a name, in their day, they were rivals.
Now, simple elevators date back hundreds of years, according to Lee Gray, an architectural historian at the University of North Carolina in Charlotte.
In fact, he said the Colosseum in ancient Rome had a simple platform that hoisted animals up into the arena from below. These early lifts relied on people pulling ropes over pulleys to make the platforms rise up a shaft.
That basic technology didn’t really change much until the 1800s, and that’s when a cascade of changes started.
In the early 1800s engineers started using water wheels for power instead of people. But elevators still didn’t go very high, they had no walls and they were just used to carry heavy things like boxes, not people. And it’s probably a good thing too, because they were not safe.
“Most of them used, not steel cables, but just thick ropes — and they broke a lot,” explained Lee Gray.
When the rope broke the platform would slide down the shaft smashing into the floor. Even though people weren’t passengers they still got hurt. Boxes and barrels could be thrown into the air and seriously injure the people working nearby.
“This is where our first Otis, Elisha Otis, comes into the picture,” said Gray.
Elisha Otis lived in New York in the mid-1800s and worked at a factory where he noticed how dangerous and unreliable the elevators were. He was inspired to start working on a fix.
He came up with safety device that activated in an emergency. If the rope broke, the sides of the hoist elevator would spring outward to push against the guide posts of the elevator shaft. The posts were covered in jagged metal teeth that would grab the sides and stop the elevator from falling.His invention worked so well, that in 1854, Elisha Otis decided to show it off at an industrial fair in New York City.
Lee Gray said he wowed audiences with a dramatic stunt.
“What he supposedly did was he built a small framework to hold a freight platform with his safety on… He would then stand on the platform and he would have his assistants haul him up so he is suspended off the ground and then they would cut the rope.”
As the crowd gasped in fear, Gray said, the safety would spring into action and stop the platform from plunging to the ground with Elisha on it. Legend has it he would end the stunt with a dramatic flourish, calling out to the astonished crowd below, “All safe gentlemen, all safe!”
He patented his idea and started selling these devices through a business that would later become the Otis Elevator Company. Remember, however, these were elevators for hoisting stuff, not people.
For that breakthrough, it took another genius innovator type named Otis.
Otis Tufts was an inventor who designed ironclad ships and steam engines. Unlike Elisha Otis, who was a builder that often improved things already out there, Tufts was more of a dreamer who came up with big ideas and had others build them.
Around the same time Elisha Otis was making freight elevators safer, Otis Tufts was asked by a hotel builder to design a fancy elevator that would actually carry people, not stuff.
Historian Lee Gray said this required him to rethink what an elevator was. Tufts was up to the challenge, adding walls, doors, mirrors, seats and even a chandelier to his elevator, which he called the “vertical railway.”Tufts’ elevators looked great, but the mechanics were kind of clunky. Rather than being lifted by cables like modern elevators, these would wind up a pole like a nut on a bolt — except the pole would turn, not the elevator. Tuft’s elevators were slow and noisy. But they were flashy and people liked them, so Tufts also decided to get into the elevator business. This is how he and the other Otis, Elisha Otis, become rivals in the cut-throat world of elevator sales.
“They both make very specific contributions,” Gray noted.
“One of them provides a technical solution that says these things can be made safe, the other one provides the conceptual vision of this is what a passenger elevator really is… how it is distinct from a freight elevator.”
Eventually, elevator designers were combining ideas from both Otises. As they became better and faster, these new machines quickly became a staple of the modern city, allowing architects to build taller and taller buildings. Soon there were six-story buildings, ten -story buildings, twenty-stories and eventually skyscrapers.
And elevators are still evolving today.
Vijay Jayachandran, executive director of engineering with the Otis Elevator Company in Connecticut, says engineers are working on smart-elevators that are connected to other functions of the building. One day soon an elevator could recognize you as you enter a building and be ready to take you to your floor without you having to push a button.
“Maybe it could have music that plays that is personalized to you,” he added, or a screen showing the latest scores from your favorite baseball team.
Another company, Thyssenkrupp, is pioneering elevators that use magnets to slide sideways in a shaft so if another elevator is coming down as the other is going up, they both simply slide sideways and safely pass each other.
“Multiple elevators in one shaft and the ability to move sideways is going to allow city planners to design buildings that look completely different than what we’re used to seeing,” said Matt Watkins from Thyssenkrupp.
Some researchers are even working on elevators that could greatly reduce the cost of sending satellites to space and, one day, take tourists there. But those are probably still a long ways off.
All of this is possible thanks to the contributions of two men named Otis, according to historian Lee Gray.
Elisha Otis brought the practical savvy and Otis Tufts supplied the grand vision. Gray said that’s often how innovation happens; one person’s good idea mixes with another person’s good idea and together they make a really great idea that changes the world.
This episode was originally posted on March 28, 2017. You can listen to that version here: