This article gives you a comprehensive guide to hinges.
vA hinge is a mechanical component that connects two objects, enabling them to rotate around a fixed axis while restricting movement along the other two axes. Essentially, a hinge functions like a journal bearing with a single degree of freedom, where a shaft rotates within a hole. Hinges facilitate rotation in one direction only, which can be yaw (the most common), pitch, or roll.
Hinges are flexible, jointed devices that attach to swinging parts, functioning as mechanical bearings to connect two moving objects or points. They enable relative movement between the objects while restricting movement to a single angle, limiting the range of motion to that specific plane.
Hinges are commonly used in doors, enclosures, containers, furniture, jewelry, construction, and electronics. For every application, there is a suitable design of hinge available. For a unique application, it is also possible to design and manufacture a custom hinge at a low cost.
A wide range of hinge types is available to suit different applications. For indoor furniture, barrel or concealed hinges are commonly used. Butterfly and strap hinges are ideal for main entrance doors, sheds, or wooden gates, offering decorative options. Friction and geared continuous hinges are typically used for industrial electrical enclosures. If none of these types meet your needs, custom hinges can always be designed. Here is a list of the hinge types available on the market.
Instead of the conventional journal-bearing or knuckle-and-pin assembly, ball bearings are often used to reduce friction. Ball bearings minimize friction by decreasing the contact area between moving surfaces and provide support for both radial and axial loads.
These are typically heavy-duty hinges secured to parts through welding or bolting. A block hinge features a barrel made of galvanized steel with a robust, square profile, and is reinforced with a stainless steel pin for enhanced corrosion resistance.
This type of hinge consists of two barrels, each attached to one of the connected parts. A low-friction bushing or another barrel separates these barrels. Unlike traditional hinges with leaves for attachment, bullet hinges use welded joints. They are particularly advantageous for installation in narrow frames while offering strong support.
A butt hinge, also known as a mortise hinge, is the most commonly used hinge for doors and windows. It consists of two leaves connected by a pin or shaft, with one leaf attached to the moving component (the door) and the other to the fixed frame (the door jamb). When the door or window is closed, only the pin is visible. Butt hinges can be used both indoors and outdoors; indoor models are typically made of steel for use in cabinets, while outdoor versions are crafted from corrosion-resistant stainless steel. These hinges are generally 6 inches in length or shorter and are usually installed flush with the wood surface through a mortise, which is why they are also called mortise hinges. They can be either full mortise, where both leaves are flush with the surfaces of the door and door jamb, or half mortise, where only one leaf (usually on the moving component) is flush.
Butterfly hinges resemble butt hinges but feature a more decorative design. They are commonly used on furniture doors to add a decorative touch where strength is less critical.
Case hinges are similar to butterfly hinges but are commonly used in suitcases, briefcases and so forth.
Like barrel-type hinges, this type of hinge is usually used in furniture doors. This hinge consists of two parts, the hinge cup, and the arm. Concealed hinges, also called cup or Euro hinges, are complicated in construction and have several design features. They cannot be seen from the outside making the furniture have a continuous appearance. These hinges help in freestyle rotation and can open in a small radius. They are mostly used in wooden cabinets. Its three movements in three different dimensions make it useful for many purposes. Also, this type can be adjusted after installation making viable for constructions with slight imperfections. Aside from being adjustable, some designs also have self-closing features and damping systems.
Continuous hinges are an extended and narrower version of the butt hinge. Also known as piano hinges, they feature long, narrow leaves that run the full length of the door or window, offering enhanced strength and support. This type of hinge provides robust support across the entire length of the door or lid and is often used to attach piano lids, which is why it is sometimes called a piano hinge. Continuous hinges can also be mortised into the surfaces they are attached to and are commonly found on desk doors, toolboxes, cabinets, and various doors.
This type of hinge is designed to provide consistent resistance throughout its opening and closing motions. Constant torque hinges are known for their preset torque specifications and durable cycle life. They use friction to hold doors and flaps in any desired position. These hinges are commonly used in monitors to adjust and maintain the angle.
The flag hinge features two leaves (male and female), with the pin permanently attached to one leaf. The male leaf includes the pin, which is fixed to the plate and resembles a flagpole, giving the hinge its name. The primary advantage of flag hinges is their ease of disassembly; the male leaf is secured to the female leaf primarily by gravity. Flag hinges are also known as lift-off hinges.
This type of hinge permits not only rotation but also some translation of one part relative to the other. Although it functions similarly to a butt hinge, it allows the door or cover to move away from the fixed component.
Flush hinges are designed so that the leaves sit flush against each other, with one leaf fitting inside the other. This design eliminates the need for a mortise or recess on the surface where they are attached, offering an advantage over butt hinges. Flush hinges are typically used for light load applications.
Friction or torque hinges are designed to operate like butt hinges but maintain their position over extended periods. They incorporate friction within the barrel to resist movement caused by gravity or other external forces. These hinges are especially useful in display devices and other electronic equipment.
A geared continuous hinge differs from a butt hinge by using gears and a vertical cap instead of knuckles and a pin for movement. This design is advantageous for joining two heavy objects while allowing partial rotation of one or both. However, despite its strength, a significant drawback is its limited range of motion.
H-hinges are also mortise hinges with an "H" shape. This shape is due to the smaller length of the knuckles and pin as compared to the length of the leaves.
HL-hinges are the same as H-hinges but with one leaf shaped like an "L". This is used when the door or the moving part is heavier.
Heavy duty hinges can be of any hinge design but with an added thickness to the material making it stronger. These hinges can be mortised, surface mounted, or welded depending on the application.
This type of hinge features an offset from the pin. The leaf is formed in a way to create the offset and allow overlaying making it suitable for narrow frames and small clearances. Institutional hinges can be designed to allow an end play of 270°.
Lift-off hinges, similar to flag hinges, feature male and female leaves with a permanent pin attached to the male leaf. Unlike flag hinges, the length of the leaves on lift-off hinges can match the length of the pin.
Living hinges differ from other types as they do not use knuckles or pins for attachment. Instead, they are integrated into the rigid body itself, with a section cut or thinned to allow for bending. Commonly found in plastic containers and packaging materials, living hinges are made of plastic, which provides inherent corrosion resistance. Polyethylene and polypropylene are ideal materials for living hinges due to their excellent fatigue resistance.
An offset hinge is a modified butt hinge primarily used to increase the width of doorways. The design is similar to an institutional hinge. Opening the door at a 90° angle sets the door about two inches from the doorway, leaving more space for passage. This simple modification of a butt hinge is a cost-effective way for increasing access space as compared to dismantling and constructing a wider doorway.
This type of hinge features leaves that fold into each other, similar to a flush hinge. It is commonly used in cabinets where insert, full overlay, or partial overlay configurations are needed.
A pivot hinge features pins (the pivot) attached to the top and bottom of the door, mounted against the door frame. Unlike butt hinges, which have pins located on the sides, pivot hinges allow for a wider range of rotation. This makes them ideal for doorways with high traffic in both directions.
This type of hinge features a pin release mechanism ideal for NEMA and JIC enclosures. The pin is turned or pulled to release the hinge.
A self-closing hinge is a spring-loaded hinge designed to automatically close doors. The spring provides the force needed to close the door, while a damper—either mechanical or hydraulic—slows down the door's rotation as it closes.
Spring-loaded hinges are equipped with a spring to aid in the opening and closing of doors. One type of spring-loaded hinge is the self-closing hinge, as previously mentioned. Another type is the double action spring hinge, which functions similarly to a pivot hinge but includes springs. This hinge allows the door to swing in both directions, with the springs ensuring that the door returns to the center position automatically. It is important to choose between indoor and outdoor spring hinges based on installation needs, as weatherproof or waterproof hinges have material differences essential for durability.
A spring release hinge, similar to a quick release hinge, includes a pin release mechanism that enables door removal without additional tools. This hinge has a pin held in place by a spring, and a knurled knob is pushed and turned to release the hinge.
This type of hinge is designed with limited end play, typically 90°. Stop hinges can be made as butt, continuous, strap, or weld-on hinges.
Strap hinges resemble butt hinges but feature a shorter pin and wider leaves (straps). Unlike concealed hinges, strap hinges are used for their aesthetic and decorative qualities. They are commonly found on garage and shed doors.
Weld-on hinges are used in metal enclosures or gates where the hinge is needed to be fixed permanently through welding. Their construction is similar to a butt hinge.
TA cane-bolt latch is a type of bolt anchor designed to keep doors in a fixed position, although it can occasionally function as a hinge. It features several barrels attached to a moving component, a drop bolt or rod, and a fixed hole on the mating part.
Damper hinges help the slow closing of doors or lids. It controls the speed of movement. These are also used in toilet lids.
These hinges help in light opening of doors or flaps with the help of built in springs in it.
These hinges are used to hold the object in a certain position without any secondary support. These hinges are used in flip mobile phones also.
Gravity hinges are used in bathroom doors and they work by using the weight of the door as a constant force for its closing and opening on its own
The doors where pivot hinges are attached open and close in an unconventional way. These hinges are placed at the bottom and the top of the door and facing it in an outward direction making its axis of rotation on the outside.
Drop hinges are designed for downward-opening applications, such as flaps on TV racks or drawers. When the drawers or flaps are opened, these hinges become fully flush.
Clean room hinges are specially designed for laboratories and clean areas, these hinges have brushes in between the knuckles. This plastic bushing helps remove any dust particles from entering in.
This section clarifies key terms such as leaves, barrels, and pins. In addition to defining these components, it also discusses hinge characteristics, which outline the specifications for manufacturing or purchasing a hinge.
The leaf is the plate that extends laterally from the knuckle or barrel. It is attached to the fixed or moving body through methods such as screwing, welding, or gluing. The leaf attached to the moving part rotates around the pin.
The knuckle is the hollow cylinder attached to the leaf through which the pin is inserted. When considering the hinge as a mechanical component, the knuckle can also be referred to as a bearing.
The pin is the rod or shaft that runs through the knuckles which holds the leaves together.
As illustrated in the figure, the flat surfaces of the hinge are the leaves, each attached to the parts being joined. The knuckles, or holes in the leaves, are used for screws and bolts to secure the hinge. The pin is then inserted through the knuckles to connect the leaves and enable rotation. Typically, hinges provide a revolute joint, allowing rotation only along one axis, which restricts movement to a single direction. This limits full rotation of the joined objects. Since this setup offers only one degree of freedom, a single pin cannot support multidirectional movement. However, some hinges, such as those used in doors and windows, allow for more complex motion and may use four pins to achieve this.
This is the dimension of the leaf as measured to the side parallel to the pin‘s axis.
This is the length of one knuckle or barrel.
This is the overall length of the barrels as measured parallel to the pin‘s axis.
This is the dimension of the leaf as measured to the side perpendicular to the pin‘s axis.
This is the overall width of the hinge as measured across the pin.
The paint clearance is the dimension of the gap between the outer face of the knuckles and adjacent edge of the leaf.
Side play is the degree of movement of the leaves perpendicular to the pin.
This is the degree of axial movement between the leaves.
Pitch is the distance between the end of a knuckle and the end of the adjacent knuckle on the same leaf.
Common leaf materials are steel, stainless steel, aluminum, brass, and bronze.
This is defined as the thickness of the leaves.
Slop is the loose angular movement of the leaves relative to the pin.
In this assembly, the leaves lay flat on the same plane when in an open position.
In this assembly, the leaves extend laterally from opposite sides of the pin. Reverse assembled hinges cannot close with its leaves in parallel.
End plate is the axial movement between the leaves along the pin axis. This helps in rotation of the leaves without its binding and can be measured by the distance between the knuckles when both leaves are aligned.
Hinge width is the distance between the one end of the leaf to its other end and is perpendicular to the pin.
It is the leaf length parallel to the pin.
It is the length of the knuckle that is parallel to the pin.
Pitch is the distance of the end of the knuckle to the same edge of the adjacent knuckle on the same leaf side.
It is the loose angular movement of the leaf relative to the pin.
When purchasing a hinge, several factors need to be considered. Since hinges have moving parts and bear loads from both the moving body and external forces, they often become the weakest point in the assembly. Over time, dynamic loads can cause the hinge to fatigue, leading to sagging in doors or gates. Additionally, hinges have limitations on maximum thickness due to manufacturing constraints or space restrictions. It's crucial to specify the hinge with the appropriate dimensions, material, and mechanical properties to ensure it suits the intended application.
When specifying a hinge, the load it needs to carry is a crucial factor. This will dictate the required dimensions and material for the application. To determine the correct load specification, it's important to account not only for the weight of the moving part—typically the part being supported—but also for external and dynamic loads. Additionally, the door's center of gravity can create a moment or torque on the hinge, potentially causing the door to sag over time, particularly if the door is wide and heavy.
Some hinges have limited angular movement such as the geared continuous hinge. The part or may need to revolve a full 180° or just 90° depending on the application. Check if the space can accommodate the door swing and if the swing will affect access through the door. There are different types of hinges to choose from depending on the application.
The desired movement might require friction or spring-loaded hinges to hold the moving part in a fixed position. Common examples of devices that use friction hinges include laptop covers, camera tripods, and ventilation screens.
The desired movement might require friction or spring-loaded hinges to hold the moving part in a fixed position. Common examples of devices that use friction hinges include laptop covers, camera tripods, and ventilation screens.
Another important consideration is how the hinge will be fastened to the moving and fixed parts. Hinges can be welded, bolted, or screwed onto the frame, depending on the type of service or the load they need to support. Additionally, hinges can be installed using various mounting methods, including surface mounting, concealed, flush, overlay, and more.
Hinges for furniture and doors often incorporate aesthetic elements. This could involve decorative designs, such as those found on butterfly and strap hinges. Additionally, aesthetics may dictate that hinges be concealed to maintain a smooth, uninterrupted appearance on the furniture.
The environment—whether outdoor or indoor—plays a crucial role in determining the material for the hinge. For applications requiring both corrosion resistance and high strength, stainless steel is the preferred material, particularly in saltwater environments. While plastic hinges also resist corrosion, they lack the high strength of metal options. If stainless steel is too costly, galvanized steel can be a suitable alternative. Brass and bronze provide good resistance to outdoor conditions and are often chosen for their decorative appeal due to their natural patinas.
Additional features are specialized characteristics that enable a hinge to perform specific functions, such as springs and pneumatic dampers in spring-loaded hinges. Multiple features can be incorporated into a hinge design, including pins, grease fittings, bearings, bushings, screw covers, and more.
Hinges can be manufactured through various processes such as casting, extruding, forming, or milling. Each method has its advantages and is selected based on the hinge's profile, material, cost, and available technology. For instance, forming is a cost-effective and simple way to mass-produce hinges with acceptable tolerances, but it produces components with lower strength. If heavy-duty hinges are needed, milling or casting may be preferred due to their ability to produce stronger products.
Casting is a process in which liquid metal is poured into a mold cavity that defines the shape of the product. It is one of the oldest metalworking techniques used to manufacture hinges. To create a cast hinge, a pattern of the desired shape is first made from wood, metal, plastic, or plaster. For the barrel, a sand or metal figure is used to form the hollow interior. The mold is prepared by packing a special type of sand around the pattern within a frame called a flask. Once the sand is packed, the hinge pattern is removed, leaving a cavity in the mold. Molten metal is then poured into this cavity and allowed to solidify. After solidification, the mold is broken, and the sand is removed from the casting. The cast hinge is then cleaned, smoothed, and heat-treated to enhance its properties.
Extrusion is a metalworking process (also used for plastics) where metal is pushed through a die to create a shape with a specific cross-sectional profile. This profile remains consistent along the length of the extruded material. For butt hinges, the extruded metal is then milled and cut to the required leaf length and pitch. In contrast, geared continuous hinges do not require additional milling because their cross-section is uniform throughout. Aluminum is commonly used for extruded hinges, and the hinge's gauge can be increased by using a die with thicker hollow sections, which enhances the hinge's strength.
Metal forming a hinge involves using a thin blank sheet that is cut and subjected to plastic deformation with tools like rollers and dies. Like casting, metal forming through hot forging is one of the earliest methods used in metalworking. A common forming process is stamping, where blanks are pressed into a die designed to apply the required pressure to accurately shape the hinge. Stamped hinges offer high dimensional precision and are produced at a lower cost compared to cast or extruded hinges. Additionally, cold forming processes strengthen and harden the material, improving its gauge. However, a limitation of forming hinges is that the gauge is restricted; as the plate thickness increases, forming becomes more challenging.
This process involves removing excess material from a metal workpiece using lathes, shapers, drills, or milling machines. Milling is particularly effective for producing hinges with precise dimensions. Milled hinges can be made thicker, akin to those produced through casting and extrusion methods.
After shaping the hinge, secondary processes are applied to enhance its properties. These processes include heat treatment, galvanizing, coating, painting, and polishing. Heat treatment imparts desired mechanical properties such as toughness, strength, and hardness. Galvanizing, coating, and painting provide corrosion resistance, especially for outdoor environments. Polishing, burnishing, and buffing are performed to achieve a decorative finish on hinges.
One thing must be considered before installing hinges. It is important to maximize the distance between two hinges, as it helps to minimize the load capacities and prevent door sagging.
Hinges are used widely in all areas of life from medical, industries, military to agriculture.
A hinge is a movable joint or mechanism that joins two items together. The hinge is one of the most popular categories of mechanical bearings. Butt hinges are a particular kind of hinge that have rectangular pieces that...
A concealed hinge, also known as a hidden or European hinge, is a type of hinge that has parts invisible to the onlooker when the door is closed. They are commonly used in cabinet doors to add an aesthetically pleasing and...
A continuous hinge is an extended single unit hinge that spans the full length of a door, cabinet, lid, or enclosure entrance. They are made of lightweight metals and can be cut to fit the size of any opening...
A friction hinge works by creating a specific tolerance in between the mechanical components. It works based on the principle of torque that can be achieved by applying a desired amount of force. Some other additions to these hinges such as...
A spring hinge is a self-closing hinge that automatically closes two connected workpieces using the action of a spring that is loaded into the hinge's barrel. They can be found in a wide variety of products such as...
Stainless steel hinges connect two components while allowing them to move in relation to one another. They can have various leafs shaped like rectangles and other forms depending on the type of stainless steel hinge. Stainless steel hinge leafs are...
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