This blog post examines how reliable the safety mechanisms of elevators—an essential mode of daily transportation—truly are, and explores the direction future technology will take.
If you live in a high-rise apartment, you’ve likely experienced the inconvenience of elevator inspections several times a year. It’s precisely during these times that we truly appreciate how vital elevators are. Without them, even climbing a few floors would be a major hassle, and transporting goods or urgently moving patients could become significantly difficult. Especially in an era overflowing with high-rise buildings like today, elevators have become more than just a convenience; they are a core element of architectural design and building management. Without the invention of the elevator, the super-tall buildings now emerging in many countries around the world would never have been possible.
The invention of the elevator can also be seen as a symbol of scientific and technological progress. The human desire to ascend to greater heights has persisted throughout history, evolving from the early reliance on stairs to the gradual incorporation of mechanical devices. This progression ultimately led to the creation of the modern elevator. Elevators utilize the principle of the pulley. In ancient times, to easily draw water from wells, a wheel was suspended from the ceiling with a rope attached. One end of the rope was connected to a gourd, and the other end to a handle. Pulling the rope at the handle end would cause the gourd attached to the opposite end to move up and down. This is the fixed pulley.
So how is this fixed pulley principle applied to elevators? To understand this, we must first know the elevator’s structure. The enclosed space where passengers board in an elevator is called the ‘car’. At the very top of the elevator shaft, where the elevator moves, a fixed pulley and an electric motor are installed. A steel rope is strung over the fixed pulley. One end of this rope is attached to the car, while the other end is connected to a counterweight that balances the elevator’s weight when unoccupied. The electric motor mounted on the ceiling winds the rope, thereby moving the car up and down. If the fixed pulley were like a well bucket, winding the rope would require significant force. However, because a counterweight is suspended on the rope opposite the car, the car can be moved up and down with relatively little force.
An elevator is not merely a device for moving people; it is a complex system incorporating various safety devices and scientific principles. Horror movies often feature scenes where elevator ropes snap, causing a fall, or where malfunctions lead to accidents. In reality, some people fear riding elevators due to concerns about such accidents. However, the probability of such accidents occurring in real life is said to be nearly zero. This is because elevators are equipped with over 20 built-in safety devices.
First, the ropes used in elevators are steel cables made by bundling 30 or more strands of wire into one bundle, with 6 to 8 such bundles combined. These cables can withstand a force 12 times the weight of the elevator at its maximum load. This means the risk of the rope breaking is low unless it is deliberately severed. Even if a rope were to break due to wear or corrosion, the elevator would not experience free fall. If the car’s descent speed increases to exceed 1.3 times the design speed, the power is automatically cut off. If it exceeds 1.4 times the design speed, the emergency stop device activates, directly engaging the rails to halt the car. Nevertheless, to prepare for the unlikely event of a free fall, the elevator shaft floor incorporates shock absorbers to mitigate impact. Thanks to these multi-layered safety mechanisms, people can move between floors of tall buildings without anxiety.
Elevators, functioning like the arteries of a building by transporting people to each floor, will continue to evolve as more diverse high-rise structures emerge. Future elevator technology is expected to be far more innovative than current systems. Elevators currently under scientific research include those that ascend along rails without ropes, like vertically moving trains, and horizontally moving elevators. These elevators will play a crucial role not only in moving people within high-rise buildings but also in realizing the concept of large-scale vertical cities. Additionally, NASA is planning to install an elevator connecting to space to transport spacecraft. After launching satellites, they intend to establish a 96,000-kilometer train track orbit connecting these satellites to Earth. We look forward to the day when the scene from Roald Dahl’s novel ‘Charlie and the Great Glass Elevator’ becomes reality.
