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.
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.
Thetford is a market town and civil parish in the Breckland district of Norfolk, England. It is on the A11 road between Norwich and London, just east of Thetford Forest. The civil parish, covering an area of 29.55 km2 (11.41 sq mi), has a population of 24,340.
There has been a settlement at Thetford since the Iron Age, and parts of the town predate the Norman Conquest; Thetford Castle was established shortly thereafter. Roger Bigod founded the Cluniac Priory of St Mary in 1104, which became the largest and most important religious institution in Thetford. The town was badly hit by the dissolution of the monasteries, including the castle's destruction, but was rebuilt in 1574 when Elizabeth I established a town charter. After World War II, Thetford became an "overspill town", taking people from London, as a result of which its population increased substantially. Thetford was the headquarters of Tulip International, large-scale manufacturers of bacon, beef and pork until its closure in 2010.
Thetford railway station is served by the Breckland line and is one of the best surviving pieces of 19th century railway architecture in East Anglia.