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A doorstop (also door stopper, door stop or door wedge) is an object or device used to hold a door open or closed, or to prevent a door from opening too widely. The same word is used to refer to a thin slat built inside a door frame to prevent a door from swinging through when closed.
The eye screw is usually screwed into the adjacent wall or onto the door itself. Used to hold a cupboard, door or gate open or shut. [9] A cabin hook is used in many situations to hold a door open, like on ships to prevent doors from swinging and banging against other woodwork as the ship moves due to wave action.
An improved "shear" electromagnetic lock was patented on May 2, 1989, by Arthur, Richard and David Geringer of Security Door Controls, an access control hardware manufacturing firm. The device outlined in their designs was the same in principle as the modern magnetic lock consisting of an electromagnet and an armature plate.
A door closer is a mechanical device that regulates the speed and action of a door’s swing. [1] Manual closers store the force used to open the door in some type of spring and reuse it to close the door. Automatic types use electricity to regulate door swing behavior. Door closers can be linked to a building's fire and security alarm systems. [2]
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Coiled springs appeared early in the 15th century, [2] in door locks. [3] The first spring powered-clocks appeared in that century [3] [4] [5] and evolved into the first large watches by the 16th century. In 1676 British physicist Robert Hooke postulated Hooke's law, which states that the force a spring exerts is proportional to its extension.