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 Rotation around a fixed axis is a special case of rotational motion. The fixed-Cartesian coordinate system, axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as nutation, wobbling or ...
: all other translations or
rotations Rotation, or spin, is the circular movement of an object around a ''axis of rotation, central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A t ...
being prevented, and thus a hinge has one degree of freedom. Hinges may be made of flexible material or of moving components. In
biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of Cell (biology), cells that proce ...
, many
joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...
s function as hinges, like the elbow joint.


Ancient remains of stone, marble, wood, and bronze hinges have been found. Some date back to at least
Ancient Egypt Ancient Egypt was a civilization in Northeast Africa situated in the Nile Valley. Ancient Egyptian civilization followed prehistoric Egypt and coalesced around 3100Anno Domini, BC (according to conventional Egyptian chronology) with the ...
. In
Ancient Rome In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 ...
, hinges were called cardō and gave name to the goddess Cardea and the main street
Cardo A cardo (plural ''cardines'') was a north–south street in Ancient Roman cities and military castra, camps as an integral component of city planning. The cardo maximus, or most often the ''cardo'', was the main or central north–south-oriented ...
. This name cardō lives on figuratively today as "the chief thing (on which something turns or depends)" in words such as ''
cardinal Cardinal or The Cardinal may refer to: Animals * Cardinal (bird) or Cardinalidae, a family of North and South American birds **''Cardinalis'', genus of cardinal in the family Cardinalidae **''Cardinalis cardinalis'', or northern cardinal, the ...
''. According to the OED, the English word hinge is related to '' hang''.

Door hinges

; Barrel hinge: A barrel hinge consists of a sectional barrel (the knuckle) secured by a pivot. A ''barrel'' is simply a hollow
cylinder A cylinder (from ) has traditionally been a Solid geometry, three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a Prism (geometry), prism with a circle as its base. A cylinder ...
. The vast majority of hinges operate on the barrel principle. ; Butt hinge / Mortise hinge: Any hinge which is designed to be set into a door frame and/ or door is considered to be a butt hinge or a mortise hinge. A hinge can also be made as a half-mortise, in which case only one half of the hinge is mortised and the other is not. Most mortise hinges are also barrel hinges by virtue 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: These are a decorative variety of barrel hinge with leaves somewhat resembling the wings of a butterfly ; Case hinges: Case hinges are similar to a butt hinge however usually more of a decorative nature most commonly used in suitcases, briefcases, and the like. ; Concealed hinge: These are used for furniture doors (with or without self-closing feature, and with or without damping systems). They are made of two parts: One part is the hinge cup and the arm, the other part is the mounting plate. Also called "cup hinge", or "Euro hinge", as they were developed in Europe and use metric installation standards. Most such 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. Continuous hinges are manufactured with or without holes. ; Flag hinge: these consist of a single leaf attached (in the male variety) to a pin. When used, the pin is inserted into the other (female) portion of the hinge. This allows the objects to be easily removed (for example, a removable door). They are manufactured in right-hand and left-hand configurations. ;H hinge: These barrel hinges are shaped like an H and used on flush-mounted doors. Small H hinges () tend to be used for cabinets hinges, while larger hinges () are for passage doors or closet doors. ; HL hinge: These were common for passage doors, room doors, and closet doors in the 17th, 18th, and even 19th centuries. On taller doors, H hinges were occasionally used in the middle along with the HL hinges. ; Pivot hinge: This hinge pivots in openings in the floor and the top of the door frame. Also referred to as a double-acting floor hinge. This type is found in ancient dry stone buildings and rarely in old wooden buildings. These are also called haar-hung doors. They are a low-cost alternative for use with lightweight 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 auto closes a door. ;Spring hinge: This is a spring-loaded hinge made to provide assistance in the closing or the opening of the hinge leaves. A ''spring'' is a component of a hinge, that applies force to secure a hinge closed or keep a hinge opened. ; Swing Clear hinge: Swing Clear Door Hinges (aka Offset Door Hinges) are perfect for residential and commercial doors, as they allow doors to swing completely clear of openings. Swing Clear Hinges can easily comply with Fair Housing Act (FHA) code by providing a minimu
ADA 32” clearance
clearance when using a 34” door slab. ;Living hinge: This hinge takes advantage of the flexibility of plastic to create a join between two objects without any knuckles or pins. They are molded as a single piece, never become rusted, do not squeak, and have several other advantages over other hinges, but the plastic makes them more susceptible to breakage. Other types include: *Coach hinge *Counterflap hinge *Cranked hinge or storm-proof hinge *Double action non-spring *Double action spring hinge *Flush hinge *Friction hinge *Lift-off hinge *Pinge: A hinge with a quick release pin. *Rising butt hinge *Security hinge *Tee hinge

Building access

Since at least
medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
times there have been hinges to draw bridges for defensive purposes for fortified buildings. Hinges are used in contemporary
architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and construction, constructin ...
where building settlement can be expected over the life of the building. For example, the Dakin Building in
Brisbane Brisbane ( ) is the capital and most populous city of the states and territories of Australia, Australian state of Queensland, and the list of cities in Australia by population, third-most populous city in Australia and Oceania, with a populati ...
California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
, 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. These are included to reduce or eliminate the transfer of bending stresses between structural components, typically in an effort to reduce sensitivity to
earthquakes An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
. 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''.


People have developed a variety of self-actuating, self-locking hinge designs for spacecraft deployable structures such as
solar array A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and co ...
panels, synthetic aperture radar antennas, booms, radiators, etc.

Hinge terminology


;Pin: The rod that holds the ''leaves'' together, inside the ''knuckle''. Also known as a
pintle A pintle is a pin or bolt, usually inserted into a gudgeon, which is used as part of a pivot or hinge. Other applications include pintle and lunette ring for towing, and pintle pins securing casters in furniture. Use Pintle/gudgeon sets have ma ...
. ;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''.


; 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 ; Door Stop: A colloquialism referring to loose angular movement of the leaves relative to the pin.

Other types

; Butler tray hinge: Folds to 90 degrees and also snaps flat. They are for tables that have a tray top for serving. ; Carpentier joint: A hinge consisting of several thin metal strips of curved cross section. ;Card table hinge: Mortised into edge of antique or reproduction card tables and allow the top to fold onto itself. ; 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
handcuffs Handcuffs are Physical restraint, restraint devices designed to secure an individual's wrists in proximity to each other. They comprise two parts, linked together by a Link chain, chain, a hinge, or rigid bar. Each cuff has a rotating arm whi ...
: 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. ;Piano hinge: (or coffin hinge) a long hinge, originally used for
piano The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a musica ...
lids, but now used in many other applications where a long hinge is needed. ; Living hinge: a hinge consisting of material that flexes ;
Hinged expansion joint A hinged expansion joint is a metallic assembly, that can rotate in a single plane, used to absorb changes resulting from piping thermal expansion or contraction.image:Hinged-expansion-joint.jpg, alt=Hinged Expansion Joint, Hinged Expansion Joint - ...
: an expansion joint with hinges that allow the unit to bend in a single plane


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 Tic Tac (stylized as "tic tac") is a brand of small, hard mint manufactured by the Italian company Ferrero. They were first produced in 1969 and are now available in a variety of flavours in over 100 countries. Tic Tacs are usually sold in sm ...
box. File:Hinged Handcuffs 1.jpg, Hinged
handcuff Handcuffs are Physical restraint, restraint devices designed to secure an individual's wrists in proximity to each other. They comprise two parts, linked together by a Link chain, chain, a hinge, or rigid bar. Each cuff has a rotating arm whi ...
s File:Hinge 03.jpg, A piano hinge. File:Continuoushinge.jpg, A continuous hinge. file:Waterson_K51SW.jpg , Swing Clear Hinge

See also

* Hinge bender, a tool for adjusting hinges * * * * *
Hinge joint A hinge joint (ginglymus or ginglymoid) is a bone joint in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane. According to one classification system they are said to be uniaxial (having ...
, a skeletal bone joint functioning like a hinge


External links

Hinge Terminology
Hingecraft; graphics visualizing many terms
Guden Hinges and Industrial Hardware: Glossary
{{Authority control Hardware (mechanical) Door furniture Linkages (mechanical)