History of the Automatic Door

New York is the biggest city in the country. Naturally, a place with that many people and that many buildings has tons of doors. All that opening and closing while entering office buildings, hotels, supermarkets and countless other structures can get tiring. That’s why so many of them have automatic doors. Just approach the building, the doors slide open and in you go. They automatically close behind you. It’s an invention most of us take for granted since automatic doors are ubiquitous. Though they may seem like a 20th Century invention, the first automatic door was actually built in the 1st Century. Surprising though that may be, it’s true. Here is a brief history of automatic doors.

Heron of Alexandria

The automated sliding entrances such as Ellison doors New York are evolutions of a device from the ancient world. Heron of Alexandria was a Greek engineer and mathematician who lived in Roman Egypt in the city that is attached to his name. Many historians consider him the greatest inventor of antiquity. Among his creations was the windwheel, the first documented use of the power of the wind on land. He also built the first vending machine which dispensed a given amount of holy water when a coin was placed in a slot.

The Aeolipile

His early steam engine, the aeolipile, also known as Heron’s engine, predated the industrial revolution by 17 centuries. It had several applications, one of which was to open the doors of a temple. The engine was ingenious for its time. A fire burned in an altar. heating air in a sealed chamber. As the air expanded it displaced water in the chamber which gradually filled a bucket. As the weight of the bucket increased, it was pulled down by gravity, taking with it an attached rope. The other end of the rope pulled the doors to the temple open. The world’s first automatic door!

Modern Automatic Doors

The first modern automatic door, invented in 1931, used an optical device or electric eye to detect the approach of a person. It then triggered the door to open. In 1954, the first sliding automatic door was invented, utilizing an actuator in a mat that opened the door when stepped on.

The automatic door is everywhere and a common part of most people’s lives. The next time you step through one, think of the ancient Greek genius Heron, and how it started it all.