How Do Automatic Doors Work?
Doors — known as automatic doors — open and close with the help of simple technology, they operate with the help of sensors. Sensors do exactly what they sound like they’d do: they sense things. There are many different types of sensors that can sense different types of things, such as sound, light, weight, and motion. For example, some automatic doors operate when they’re triggered by sensors that sense weight. These weight sensors might be disguised in a rubber mat in front of the door. When you step on the mat, the sensors send a signal to the automatic doors that tells them to open.
Other automatic doors operate on optic or motion sensors. These sensors might be mounted above a set of automatic doors or built on the top or the sides of the frame of the automatic doors. When these optic or motion sensors sense motion nearby, they trigger the automatic doors to open and then close. This is why, when you approach a set of automatic doors, they will open as soon as you get close enough to activate the sensors.
Automatic doors have many useful purposes, which is why you can find them in many different types of locations. From supermarkets to airports and many types of large buildings, automatic doors make it easier for people to get into and out of buildings. They are especially helpful for people who are handicapped. Similar to revolving doors, automatic doors also help to save energy, since they limit the amount of time that doors are open to only those times people are entering or exiting a building. And if you’ve ever shopped until your hands are full of bags, you know how handy automatic doors can be when it’s time to head to the car!
In the 1st Century AD, Greek mathematician Heron of Alexandria invented the first known automatic door. He described two different automatic door applications. The first application used heat from a fire lit by the city’s temple priest. After a few hours atmospheric pressure built up in a brass vessel causing it to pump water into adjacent containers. These containers acted as weights that, through a series of ropes and pulleys, would open the temple’s doors at about the time people were to arrive for prayer. Heron used a similar application to open the gates to the city.
In 1931, engineers Horace H. Raymond and Sheldon S. Roby of the tool and hardware manufacturer Stanley Works designed the first model of an optical device triggering the opening of an automatic door. The invention was patented and installed in Wilcox’s Pier Restaurant in West Haven, Connecticut for the benefit of waiters carrying plates of food and drink. The entire system plus installation was sold for $100.
In 1954, Dee Horton and Lew Hewitt invented the first sliding automatic door. The automatic door used a mat actuator. In 1960, they co-founded Horton Automatics Inc and placed the first commercial automatic sliding door on the market.