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Shades of blue: standard door closer. Shades of red: opener gears. Gold: motor. Operators use various internal technologies. Some are built on top of a standard door closer. To open the door, the operator forces the closer in the opening direction. Then, the closer closes the door. The user may open the door manually, using just the door closer.
A door operator may be triggered in various ways: Approach Sensor (such as a radar sensor) - the door opens when a user approaches it. Pushbutton - the door opens when a user presses a button. Access control - the door opens when an access control system determines the user is authorized to go through. Automatically (in the case of elevators).
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. [5] With the invention of the Gunn diode, microwave motion detectors became common in automatic doors in the 1970s.
A crash bar (also known as a panic exit device, panic bar, or bump bar) [1] [2] is a type of door opening mechanism which allows users to open a door by pushing a bar. While originally conceived as a way to prevent crowd crushing in an emergency, crash bars are now used as the primary door opening mechanism in many commercial buildings.
Door chain - A device to secure door opening; Door closer – Mechanical or electromagnetic device to close an open door (in the event of a fire) [3] Door opener - Automatic door opening device activated by motion sensors or pressure pads; Door damper – A hydraulic device employed to slow the door's closure; Door knocker
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In a manual mantrap, a guard locks and unlocks each door in sequence. An intercom and/or video camera are often used to allow the guard to control the trap from a remote location. In an automatic mantrap, identification may be required for each door, sometimes even different measures for each door.
Mangione's writings, obtained by ABC News, claimed that the U.S. has the most expensive health care system in the world, but ranks about No. 42 in life expectancy.