Hinge
Encyclopedia
A hinge is a type of bearing
Bearing (mechanical)
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

that connects two solid objects, typically allowing only a limited angle of rotation
Angle of rotation
In mathematics, the angle of rotation is a measurement of the amount, the angle, that a figure is rotated about a fixed point, often the center of a circle....

between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation. Hinges may be made of flexible material
Flexure bearing
A flexure bearing is a bearing which allows motion by bending a load element.A typical flexure bearing is just one part, joining two other parts. For example, a hinge may be made by attaching a long strip of a flexible element to a door and to the door frame...

or of moving components. In biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

, many joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...

s function as hinges.

## Door hinges

There are many types of door hinges. The main types include:

Barrel hinge: which is a sectional barrel secured by a pivot. A barrel is a component of a hinge, that has a hollow cylinder
Cylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...

shaped section where the rotational bearing force is applied to the pivot, and may also have a screw
Screw
A screw, or bolt, is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the...

shaped section for fastening and/or driving the pivot.
Pivot hinges: which pivot 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.
Butt/Mortise hinges: usually in threes or fours, which are inset (mortised) into the door and frame. Most residential hinges found in the U.S. are made of steel, although mortise hinges for exterior doors are often made of brass or stainless steel to prevent corrosion.
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.
Continuous hinges, or piano hinges: This type of hinge is also known as a piano hinge. It runs the entire length of the door, panel, or box. Continuous hinges are manufactured with or without holes. These hinges also come in various thicknesses, pin diameters, and knuckle lengths.
Concealed hinges: used for furniture doors (with or without self-closing feature, and with or without dampening systems). They are made of 2 parts: One part is the hinge cup and the arm; the other part is the mounting plate. Also Euro/cup hinge.
Butterfly hinges, or Parliament (UK) Hinges: These were known as dovetail hinges from the 17th century onwards and can be found on old desks and cabinets from about 1670 until the 18th century. The form of these hinges varied slightly between manufacturers, and their size ranged from the very large for heavy doors to the tiniest decorative hinge for use on jewellery boxes. Many hinges of this type were exported to America to support the home trade's limited supply. They are still found to be both fairly cheap and decorative, especially on small items.
Flag hinges: a flag hinge can be taken apart with a fixed pin on one leaf. Flag hinges can also swivel a full 360 degrees around the pin. Flag hinges are manufactured as a right hand and a left hand configuration.
Strap hinges: Strap hinges are an early hinge and used on many kinds of interior and exterior doors and cabinets.
H hinges: Shaped like an H and used on flush-mounted doors. Small H hinges (3 –) tend to be used for cabinets hinges, while larger hinges (6 –) are for passage doors or closet doors.
HL hinges: Large HL hinges 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.

Other types include:
• Counterflap hinge
• Flush hinge
• Coach hinge
• Rising Butt hinge
• Double action spring hinge
• Tee hinge
• Friction hinge
• Security hinge
• Cranked hinge or stormproof hinge
• Lift-off hinge
• Self closing hinge
• Butt hinge

## Building access hinges

Since at least medieval times there have been hinges to draw bridges for defensive purposes for fortified buildings.
Hinges are used in contemporary architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

where building settlement can be expected over the life of the building. For example, the Dakin Building
Dakin Building
The Dakin Building is an architectural award-winning class A office building on the San Francisco Bay in Brisbane, California. Serving as a corporate headquarters building for several companies of national prominence, it was built from the profits of the Garfield character whose licensed products...

, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

was designed with its entrance ramp on a large hinge to allow settlement of the building built on piles over bay mud
Bay mud
Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles...

. This device has been effective.

## Other hinges

Butler tray hinge: Fold to 90 degrees and also snap 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.
Drop leaf table hinge: Mounted under the surface of a table with leaves that drop down. They are most commonly used with rule joints.
Piano hinge: a long hinge, originally used for piano
Piano
The piano is a musical instrument played by means of a keyboard. It is one of the most popular instruments in the world. Widely used in classical and jazz music for solo performances, ensemble use, chamber music and accompaniment, the piano is also very popular as an aid to composing and rehearsal...

lids, but now used in many other applications where a long hinge is needed.

• Door
Door
A door is a movable structure used to open and close off an entrance, typically consisting of a panel that swings on hinges or that slides or rotates inside of a space....

• Floating hinge
Floating hinge
A floating hinge is a hinge that, while able to behave as a normal hinge, enables one of the objects to move away from the other - hence float. In effect the hinge allows for two parallel axes of rotation, one for each object joined by the hinge, and each axis can be moved relative to the position...

• Living hinge
Living hinge
A living hinge is a thin flexible hinge made from plastic that joins two rigid plastic parts together, allowing them to bend along the line of the hinge...

• Plain bearing
Plain bearing
A plain bearing, also known as a plane bearing or a friction bearing is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore the journal slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole...