Hinge

Building access

Since at least the medieval period, there have been hinges to draw bridges 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, 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 structures such as solar array panels, synthetic aperture radar antennas, booms, radiators, etc.

Terminology

• 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.
• 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.
• 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 – A colloquialism referring to loose angular movement of the leaves relative to the pin.

Types

Barrel hinge

A barrel hinge consists of a sectional barrel (the knuckle) secured by a pivot. A barrel is simply a hollow cylinder. The vast majority of hinges operate on the barrel principle.

Butt hinge / Mortise hinge

Any hinge designed to be set into a door or door frame is considered a butt hinge or 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

Butterfly or parliament hinges are hinges that hold surfaces flush when opened 180 degrees.

Case hinge

Case hinges are similar to butt hinges, but are usually more decorative; most commonly used in suitcases, briefcases, and the like.

Concealed hinge

Used for furniture doors (with or without a self-closing features and/or damping systems), concealed hinges 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

Continuous or piano hinges are a variety of barrel hinge that run the entire length of a door, panel, box, etc. They are manufactured with or without holes.

Flag hinge

Flag hinges are simple two-part hinges 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

H hinges are capital H-shaped barrel hinges used on flush-mounted doors. Small H hinges (3–4 in or 76–102 mm) tend to be used for cabinets, while larger ones (6–7 in or 150–180 mm) are for passage doors and closet doors.

HL hinge

HL hinges were 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.

One-way hinge

A one-way hinge is a hinge which can only swing on one direction; it is the opposite of a two-way or double-action hinge.

Pivot hinge

A pivot 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. Doors with these hinges may be called haar-hung doors.

Self-closing hinge

Self-closing hinges are hinges that have an built-in mechanism to automatically close, often with a speed control function. The same as spring hinge, they usually use springs to provide force to close the door and have a mechanical or hydraulic damper to control door close speed. Self-closing hinges function as both hinges and door closers.

Spring hinge

Spring hinges are spring-loaded hinges that provide assistance in closing or opening the hinge leaves. An inner spring applies force to keep the hinge closed or opened.

Swing clear hinge

Also called offset door hinges, swing clear hinges allow doors to swing completely clear of their openings. They are often used to comply with Fair Housing Act (FHA) code by providing the minimum 32” clearance when using a 34” door slab.

Butler tray hinge

Butler tray hinges fold to 90 degrees and snap flat. They are for tables that have a tray top for serving.

Card table hinge

Card table hinges are mortised into the edges of antique or reproduction card tables and allow the top to fold onto itself.

Carpentier joint

Carpentier joints are hinges consisting of several thin metal strips of curved cross section.

Drop-leaf table hinge

Drop-leaf table hinges are mounted under the surface of a table with leaves that drop down. They are most commonly used with rule joints.

Hinged expansion joint

Hinged expansion joints are joints with hinges that allow the object or unit to bend in a single plane.

Living hinge

A hinge of flexible material (often plastic) that creates a join between two objects without any knuckles or pins is a living hinge. Molded as a single piece, these hinges have fewer moving parts and have several advantages over other designs, but are more susceptible to fatigue and breakage.

Other

Other types of hinges include:

• Coach
• Counter flap
• Cranked or storm-proof
• Double action non-spring
• Double action spring
• Flush
• Friction
• Lift-off
• Pinge (with a quick-release pin)
• Rising butt hinges or cam lift hinges have a spiral knuckle that lifts the door as it opens, allowing it to clear carpets or uneven floors, and closing it gravitationally
• Security
• Tee