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Heron describes in detail and through drawings many mechanical devices operated by air, water or steam pressure.  Most of these devices he actually constructed.  These include a steam turbine engine he called an aeolipile (Greek for wind ball), a toy jet propelled vehicle, automated dancing puppets, a steam powered fire engine, a water clock, heavy lifting machines, a coin operated vending machine, a pipe organ and a machine to automatically change scenery in the cities theatre.  One of Heron’s designs for a steam engine was discovered in 1668.  Heron’s designs may have served as inspiration to Thomas Savery who invented a steam engine in 1698 to pump water from mine shafts.  Later Thomas Watt invented the modern piston driven steam engine in 1765.

Hero described^[12] the construction of the aeolipile (a version of which is known as Hero’s engine) which was a rocket-like reaction engine and the first-recorded steam engine (although Vitruvius mentioned the aeolipile in De Architectura some 100 years earlier than Hero). It was created almost two millennia before the industrial revolution. Another engine used air from a closed chamber heated by an altar fire to displace water from a sealed vessel; the water was collected and its weight, pulling on a rope, opened temple doors.^[13] Some historians have conflated the two inventions to assert that the aeolipile was capable of useful work.^[14]

• The first vending machine was also one of his constructions; when a coin was introduced via a slot on the top of the machine, a set amount of holy water was dispensed. This was included in his list of inventions in his book Mechanics and Optics. When the coin was deposited, it fell upon a pan attached to a lever. The lever opened up a valve which let some water flow out. The pan continued to tilt with the weight of the coin until it fell off, at which point a counter-weight would snap the lever back up and turn off the valve.^[15]
• A windwheel operating an organ, marking the first instance in history of wind powering a machine.^[4][5]
• Hero also invented many mechanisms for the Greek theater, including an entirely mechanical play almost ten minutes in length, powered by a binary-like system of ropes, knots, and simple machines operated by a rotating cylindrical cogwheel. The sound of thunder was produced by the mechanically-timed dropping of metal balls onto a hidden drum.
• The force pump was widely used in the Roman world, and one application was in a fire-engine.
• A syringe-like device was described by Hero to control the delivery of air or liquids.^[16]
• In optics, Hero formulated the principle of the shortest path of light: If a ray of light propagates from point A to point B within the same medium, the path-length followed is the shortest possible. It was nearly 1000 years later that Alhacen expanded the principle to both reflection and refraction, and the principle was later stated in this form by Pierre de Fermat in 1662; the most modern form is that the path is at an extremum.
• A standalone fountain that operates under self-contained hydrostatic energy (Hero’s fountain)
• A programmable cart that was powered by a falling weight. The “program” consisted of strings wrapped around the drive axle.^[17]

This pumped water into adjacent holding containers that acted as weights, enabling a series of ropes and pulleys to open the temple’s doors when people were arriving for prayer. He later implemented a similar application to open the City gates.

Heron’s automatic doors were among more than 80 mechanical appliances that he designed to work by water pressure, steam or air.

A foot sensor-activated automatic door was constructed in China in the 17th century, according to historian Joseph Needham in his 1986 book, Science and Civilization in China. Emperor Yang of Sui, who reigned from 604–618 had it installed for the royal library.

In 1910, author HG Wells refers to an automatic door in his book, When the Sleeper Wakes. It described how two men walked up to an “apparently solid wall” that “rolled up with a snap” to allow them access before it closed again.

Despite these early references, it wasn’t until 1954 that Americans Dee Horton and Lew Hewitt were credited with the invention of the first automatic doors as we know them today – after studying the difficulties faced by people trying to use swing doors in windy Corpus Christi, Texas. Using a mat actuator, the first automatic door was installed there in 1960. The first commercial automatic sliding doors appeared on the market the same year, establishing a new industry.

Throughout the 1960s, automatic sliding doors became progressively more common. Pneumatic-powered and with an emergency break-out feature and electric floor mat activation, their application became increasingly widespread in commercial buildings such as in large banks, hotels and various public buildings.

In the 1970s, motion detectors were invented to activate sliding doors, the concept of low-energy swing doors was introduced and the first access doors for disabled people were initiated. To coincide with the growth of the industry, the Builders’ Hardware Manufacturing Association was formed and the American National Standards Institute wrote the first standard for power-operated doors, ANSI A15610.

In the 1980s, active infrared presence sensors were introduced for safety reasons, while automatic revolving doors were launched and motion detector activation became an industry standard for sliding doors.

The first automatic folding doors were invented in the 1990s, when the automatic door industry became a global force. Active infrared sensors were soon used on all types of automatic doors.

Today, automatic doors can be found in just about every commercial building; opening as if by magic as we approach and closing efficiently behind us. Triggered by optic or motion sensors, this ensures that they open as soon as we approach them.

Modern technology can find ways of improving even the simple door! As part of our door installation survey our engineers can advise you on all the options and available and how well they may be applied to your specific property and requirement. To learn more, contact our team today and arrange for a consultation throughout Toronto.