View source for Hinge

{{Short description|Mechanical bearing connecting two objects}}
{{Other uses}}
{{More citations needed|date=January 2017}}
[[File:Carrollton New Orleans hinge brass inside.jpg|thumb|An ornate brass door hinge]]
[[Image:Hamburgerpaumelle.JPG|thumb|A barrel hinge|center]]

A '''hinge''' is a [[mechanical bearing]] that connects two solid objects, typically allowing only a limited [[angle of rotation]] between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed [[axis of rotation]], with all other [[Translation (geometry)|translations]] or [[rotations]] prevented; thus a hinge has one [[degree of freedom]]. Hinges may be made of [[Flexure bearing|flexible material]] or moving components. In [[biology]], many [[joint]]s function as hinges, such as the elbow joint.

==History==
Ancient remains of stone, marble, wood, and bronze hinges have been found. Some date back to at least [[Ancient Egypt]], although it is nearly impossible pinpoint exactly where and when the first hinges were used.<ref>{{cite web|title=Door Hinges in Antiquity (Smith's Dictionary, 1875)|url=https://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Cardo.html|access-date=April 19, 2022}}</ref>

In [[Ancient Rome]], hinges were called [[wikt:cardo#Latin|cardō]] and gave name to the goddess [[Cardea]] and the main street [[Cardo]]. This name cardō lives on figuratively today as "the chief thing (on which something turns or depends)" in words such as ''[[wikt:cardinal#English|cardinal]]''.<ref>{{cite web|title=Door Hinges in Antiquity (Smith's Dictionary, 1875)|url=https://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Cardo.html|access-date=April 19, 2022}}</ref>

According to the [[OED]], the English word ''hinge'' is related to ''[[wikt:hang#English|hang]]''.

==Door hinges==
[[File:Basic hinge.svg|thumb|Basic hinge]]
; Barrel hinge: A barrel hinge consists of a sectional barrel (the ''knuckle'') secured by a pivot. A ''barrel'' is simply a hollow [[Cylinder (geometry)|cylinder]].  The vast majority of hinges operate on the barrel principle.

; Butt hinge / Mortise hinge: Any hinge designed to be set into a door frame and/or door is considered a butt hinge or [[Mortise and tenon|mortise]] hinge. A hinge can also be made as a half-mortise, where only one half is mortised and the other is not. Most mortise hinges are also barrel hinges because of how they pivot (i.e., a pair of leaves secured to each other by knuckles through which runs a pin).

; Butterfly / Parliament (UK) hinge: A decorative variety of barrel hinge with leaves somewhat resembling the wings of a butterfly

; Case hinge: Similar to butt hinges, but usually more decorative; most commonly used in suitcases, briefcases, and the like

;[[Concealed hinge jig#Concealed hinges|Concealed hinge]]: Used for furniture doors (with or without a self-closing features and/or damping systems), they consist of two parts: (1.) the ''cup'' and ''arm'', and (2.) the mounting plate. They are also called "cup hinges", or "Euro hinges", as they were developed in Europe and use metric installation standards. Most concealed hinges offer the advantage of full ''in situ'' adjustability for standoff distance from the cabinet face, as well as pitch and roll by means of two screws on each hinge.

; Continuous / Piano hinge: This variety of barrel hinge runs the entire length of a door, panel, box, etc. They are manufactured with or without holes.

; Flag hinge: A simple two-part hinge, where a single leaf, attached to a pin, is inserted into a leaf with a hole. This allows the hinged objects to be easily removed (such as removable doors). They are made in right- and left-hand configurations.

;H hinge: These H-shaped barrel hinges are used on flush-mounted doors. Small H hinges ({{convert|3|–|4|in|mm|abbr=on|disp=or}}) tend to be used for cabinets, while larger ones ({{convert|6|–|7|in|mm|abbr=on|disp=or}}) are for passage doors and closet doors.

; HL hinge: Commonly used for passage doors, room doors, and closet doors in the 17th, 18th, and the 19th centuries. On taller doors, H hinges were occasionally used between them.

; Pivot hinge: This hinge pivots in openings in the floor and the top of the door frame. Also referred to as double-acting floor hinges, they are found in ancient dry stone buildings and, rarely, in old wooden buildings. They are a low-cost alternative for use with lightweight doors.<ref>{{cite web|title=Pivot Hinges|url=http://www.guden.com/ItemDisplay/PivotHinges|website=Guden|access-date=15 December 2016}}</ref> Doors with these hinges may be called haar-hung doors.

; Self-closing hinge: This is a spring-loaded hinge with a speed control function. The same as ''spring hinge'', usually use ''spring'' to provide force to close the door and provide a mechanical or hydraulic damper to control door close speed. That can prevent door slamming problem while [[Door closer|auto closes a door]].<ref>{{cite web|title=Self-Closing Hinges|url=http://www.watersonusa.com/solutions/spring-loaded-door-hinge|website=Watersonusa|date=26 August 2019 |access-date=September 3, 2020}}</ref>

;Spring hinge: A spring-loaded hinge that provides assistance in closing or opening the hinge leaves. An inner [[Spring (device)|spring]] applies force to keep the hinge closed or opened.<ref>{{cite web|title=Spring Hinges|url=http://www.guden.com/ItemDisplay/Spring-Hinges|website=Guden|access-date=15 December 2016}}</ref>

;Swing Clear hinge: Also called ''offset door hinges'', they are ideal for residential and commercial doors, they allow doors to swing completely clear of their openings. They can easily comply with Fair Housing Act (FHA) code by providing a minimum [https://watersonusa.com/solutions/swing-away-hinges ADA 32” clearance] when using a 34” door slab.
 
;Living hinge: A hinge of flexible plastic that creates a join between two objects without any knuckles or pins. Molded as a single piece, they never rust or squeak, and have several other advantages over other hinges, but are more susceptible to breakage.

Other types of hinges include:
*Coach
*Counterflap
*Cranked or storm-proof
*Double action non-spring
*Double action spring
*Flush
*Friction
*Lift-off
*Pinge (with a quick-release pin)
*Rising butt
*Security
*Tee

==Building access==
Since at least [[medieval]] times, there have been hinges to [[draw bridge]]s for defensive purposes for fortified buildings. Hinges are used in contemporary [[architecture]] where building settlement can be expected over the life of the building. For example, the [[Dakin Building]] in [[Brisbane, California|Brisbane]], [[California]], was designed with its entrance ramp on a large hinge to allow settlement of the building built on piles over [[bay mud]]. This device was effective until October 2006, when it was replaced due to damage and excessive ramp slope.

==Large structures==
Hinges appear in large structures such as elevated freeway and railroad viaducts, to reduce or eliminate the transfer of bending stresses between structural components, typically in an effort to reduce sensitivity to [[earthquakes]]. The primary reason for using a hinge, rather than a simpler device such as a slide, is to prevent the separation of adjacent components. When no bending stresses are transmitted across the hinge, it is called a ''zero moment hinge''.

== Spacecraft ==

A variety of self-actuating, self-locking hinges have been developed for spacecraft [[deployable structure]]s such as [[solar array]] panels, synthetic aperture radar antennas, booms, radiators, etc.<ref>
Alan M. Watt; and Sergio Pellegrino.
[http://www-civ.eng.cam.ac.uk/dsl/publications/TSR_hinge.pdf "Tape-Spring Rolling Hinges"]
p. 2.
</ref>

==Terminology==

===Components===
;Pin: The rod that holds the ''leaves'' together, inside the ''knuckle''. Also known as a '''[[pintle]]'''.
;Knuckle: The hollow—typically circular—portion creating the joint of the hinge through which the ''pin'' is set. The ''knuckles'' of either ''leaf'' typically alternate and interlock with the ''pin'' passing through all of them. (aka. '''loop''', '''joint''', '''node''' or '''curl''')
;Leaf: The portions (typically two) that extend laterally from the ''knuckle'' and typically revolve around the ''pin''.

===Characteristics===
; End play: Axial movement between the ''leaves'' along the axis of the ''pin''. This motion allows the leaves to rotate without binding and is determined by the typical distance between ''knuckles'' (knuckle gap) when both edges of the ''leaves'' are aligned.
; Gauge: Thickness of the ''leaves''.
;Hinge width: Length from the outer edge of one ''leaf'' to the outer edge of the other ''leaf'', perpendicularly across the ''pin'' (aka '''open width''').
; Hinge length: The length of the ''leaves'' parallel to the pin.
; Knuckle length: The typical length of an individual ''knuckle'' parallel to the pin.
; Leaf width: Length from the center of the ''pin'' to the outer edge of the ''leaf''.
; Pitch: Distance from the end of a knuckle to the same edge of its adjacent knuckle on the same leaf
; [[Doorstop|Door Stop]]: A colloquialism referring to loose angular movement of the leaves relative to the pin.<ref>{{cite web|url=https://www.youtube.com/watch?v=Yy9Di5FWp6c |archive-url=https://ghostarchive.org/varchive/youtube/20211212/Yy9Di5FWp6c| archive-date=2021-12-12 |url-status=live|title=Jeep JK tail gate hinge slop|last=heyok|date=28 April 2014|via=YouTube}}{{cbignore}}</ref>

==Other types==
;[[tray|Butler tray]] hinge: Folds to 90 degrees and also snaps flat. They are for tables that have a tray top for serving.
;Card table hinge: Mortised into edge of antique or reproduction card tables and allow the top to fold onto itself.
;[[Carpentier joint]]: A hinge consisting of several thin metal strips of curved cross section.
;[[Drop-leaf table]] hinge: Mounted under the surface of a table with leaves that drop down. They are most commonly used with rule joints.
;[[Hinged expansion joint]]: an expansion joint with hinges that allow the unit to bend in a single plane
;Hinged [[handcuffs]]: a restraint device designed to secure an individual's wrists in proximity to each other consisting of two cuffs linked with a double or triple hinge. Hinged handcuffs cuffs tend to restrict movement more than chain-linked handcuffs, and they can be used to generate more leverage to force a suspect's hands behind the back, or to apply pain against the wrist, forcing the subject to comply and stop resisting.<ref>{{cite web|url=https://www.tactical-life.com/lifestyle/tactics/lifesaving-handcuffing-tactics/|title=On the Job: Lifesaving Handcuffing Tactics|date=30 December 2014}}</ref>
;Hinge region: portion of [[Antibody#Structure|antibody structure]] between the [[fragment antigen-binding]] region and the [[fragment crystallizable]] region
;[[Living hinge]]: a hinge consisting of material that flexes
;Piano hinge: (or coffin hinge) a long hinge, originally used for [[piano]] lids, but now used in many other applications where a long hinge is needed.

==Gallery==
<gallery>
File:HingesOldA.jpg|Old construction of hinges in the dry stone wall near [[Bignasco]].
File:HingesOldB.jpg|Ancient pivot hinges, found in the dry stone buildings.
File:Hingebifold.JPG|A flushed door hinge.
File:Hinge2P2.jpg|A barrel hinge made of wrought iron.
File:Hinge2P3.jpg|A barrel hinge made of bronze strap.
File:Hinge3P.jpg|Increasing the number of loops to 3 allows the butt hinge axis to be fixed from both ends.
File:Topfscharnier.jpg|Door in furniture with spring to lock door both fully shut and fully open positions. It hides completely behind the door and has adjustment for fine alignment. Allows the door to open even when against a wall.
File:Hinge 01.jpg|Rusty hinges on a building exterior.
File:Drzwi biegun 0211.jpg|This door hinges on the stile and is called a haar-hung door.
File:Mint box polypropylene lid.JPG|A living hinge on the lid of a [[Tic Tac]] box.
File:Hinged Handcuffs 1.jpg|Hinged [[handcuff]]s
File:Hinge 03.jpg|A piano hinge.
File:Continuoushinge.jpg|A continuous hinge.
file:Waterson_K51SW.jpg | Swing Clear Hinge
File:Sydney Harbour Bridge hinge.jpg|Hinge on the Sydney Harbour Bridge. It was used during construction of the bridge and now accommodates thermal expansion and contraction of the bridge
</gallery>

==See also==
* [[Hinge bender]], a tool for adjusting hinges
* {{annotated link|Concealed hinge jig}}
* {{annotated link|Floating hinge}}
* {{annotated link|Geared continuous hinge}}
* {{annotated link|Plain bearing}}
* [[Hinge joint]], a skeletal bone joint functioning like a hinge

==References==
{{Reflist}}

== External links ==
{{Sister project links|commonscat=yes|n=no|q=no|s=no}}
* [http://www.hingecraft.com/Terminology.html Hinge Terminology]—Hingecraft; graphics visualizing many terms
* [http://www.guden.com/Control/glossary Guden Hinges and Industrial Hardware: Glossary]

{{Authority control}}

[[Category:Hardware (mechanical)]]
[[Category:Door furniture]]
[[Category:Linkages (mechanical)]]
[[Category:Hinges| ]]