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Automatic Door
An automatic door, also known as an auto door, is a door that opens automatically, usually on sensing the approach of a person.
In the 1st century AD, mathematician Heron of Alexandria in Roman Egypt 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.[1]
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.[2][3]
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.[4]
Lichfield (/ˈlɪtʃfiːld/) is a cathedral city and civil parish[2] in Staffordshire, England. Lichfield is situated roughly 16 mi (26 km) north of Birmingham, 8.1 miles (13.0 km) from Rugeley, 9 miles (14 km) from Walsall, 7.9 miles (12.7 km) from Tamworth and 13 miles (21 km) from Burton Upon Trent. At the time of the 2011 Census the population was estimated at 32,219 and the wider Lichfield District at 100,700.[3]
Notable for its three-spired medieval cathedral, Lichfield was the birthplace of Samuel Johnson, the writer of the first authoritative Dictionary of the English Language. The city's recorded history began when Chad of Mercia arrived to establish his Bishopric in 669 AD and the settlement grew as the ecclesiastical centre of Mercia. In 2009, the Staffordshire Hoard, the largest hoard of Anglo-Saxon gold and silver metalwork, was found 5.9 km (3.7 mi) south-west of Lichfield.
The development of the city was consolidated in the 12th century under Roger de Clinton, who fortified the Cathedral Close and also laid out the town with the ladder-shaped street pattern that survives to this day. Lichfield's heyday was in the 18th century, when it developed into a thriving coaching city. This was a period of great intellectual activity, the city being the home of many famous people including Samuel Johnson, David Garrick, Erasmus Darwin and Anna Seward, and prompted Johnson's remark that Lichfield was "a city of philosophers".
Today, the city still retains its old importance as an ecclesiastical centre, and its industrial and commercial development has been limited. The centre of the city has over 230 listed buildings (including many examples of Georgian architecture), and preserves much of its historic character.
