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A bayonet mount (mainly as a method of mechanical attachment, such as fitting a lens to a camera using a matching lens mount) or bayonet connector (for electrical use) is a fastening mechanism consisting of a cylindrical male side with one or more radial pins, and a female receptor with matching L-shaped slot(s) and with spring(s) to keep the two parts locked together. The slots are shaped like a capital letter L with serif (a short upward segment at the end of the horizontal arm); the pin slides into the vertical arm of the L, rotates across the horizontal arm, then is pushed slightly upwards into the short vertical "serif" by the spring; the connector is no longer free to rotate unless pushed down against the spring until the pin is out of the "serif".
The bayonet mount is the standard light bulb fitting in the United Kingdom and in many countries that were members of the British Empire including Australia, Hong Kong, Fiji, [1] India, Pakistan, Sri Lanka, Ireland and New Zealand, parts of the Middle East and Africa and, historically, in France and Greece.
To couple the two parts, the pin(s) on the male are aligned with the slot(s) on the female and the two pushed together. Once the pins reach the bottom of the slot, one or both parts are rotated so that the pin slides along the horizontal arm of the L until it reaches the "serif". The spring then pushes the male connector up into the "serif" to keep the pin locked into place. A practised user can connect them quickly and, unlike screw connectors, they are not subject to cross-threading. To disconnect, the two parts are pushed together to move the pin out of the "serif" while twisting in the opposite direction than for connecting, and then pulling apart.
The strength of the joint comes from the strength of the pins and the L slots, and the spring. To disengage unintentionally, the pins must break, the sleeve into which the connector slides must be distorted or torn enough to free the pins, or the spring must fail and allow the connector to be pushed down and rotate—for example due to vibration.
It is possible to push down the connector and rotate it, but not far enough to engage and lock; it will stay in place temporarily, but accidental disconnection is very likely.
Bayonet electrical connectors are used in the same applications where other connectors are used, to transmit either power or signals. Bayonet connections can be made faster than screw connections, and more securely than push-fit connections; they are more resistant to vibration than both these types. They may be used to connect two cables, or to connect a cable to a connector on the panel of a piece of equipment.
The coupling system is usually made of two bayonet ramps machined on the external side of the receptacle connector and 2 stainless steel studs mounted inside the plug connector’s coupling nut. Several classes of electrical cable connectors, including audio, video, and data cables use bayonet connectors. Examples include BNC, C, and ST connectors. (The BNC connector is not exactly as described in this article, as the male, not female, connector has the slots and spring.)
The GU-10 light fittings in common use for both halogen and LED miniature spotlight lamps have a similar means of connection but the retaining pins are fitted to the end of the lamp and also double as the electrical contacts. The pins are cylindrical but the ends have a larger diameter, resembling a T when viewed from the side. The receptacle has two slots resembling curved keyholes which have holes at one end sized to accept the pin ends. The lamp is inserted into the receptacle by placing the pins in the holes and rotating in a clockwise direction. Note that, unlike the traditional bayonet fitting, the retaining springs act laterally on the pins so no inward pressure is required to lock the lamp in the fitting. GU-10 fittings are available in heat-resistant form for use with halogen lamps which generate heat.
The first documented use of this type of fitting (without the name "bayonet") may be by al-Jazari in the 13th century, who used it to mount candles into his candle-clocks. [2] This type of fitting was later used for soldiers who needed to quickly mount bayonets to the ends of their rifles, hence the name.
The bayonet light bulb mount is the standard fitting in many former members of the British Empire [ citation needed ] including the United Kingdom, Australia, India, Ireland, and New Zealand, Hong Kong, as well as parts of the Middle East and Africa (although not Canada, which primarily uses Edison screw sockets along with the United States and Mexico). The standard size is B22d-2, often referred to in the context of lighting as simply BC or B22. Older installations in some other countries, including France and Greece use this base. First developed by St. George Lane Fox-Pitt in the UK and improved upon by the Brush Electric Company from the late 1870s onward, standard bulbs have two pins on opposite sides of the cap; [3] [4] however, some specialized bulbs have three pins (cap designation B22d-3) to prevent use in domestic light fittings. Examples of three-pin bulbs are found in mercury street lamps and fireglow bulbs in some older models of electric radiative heater. Older railway carriages in the UK also made use of a 3 pin bulb base to discourage theft. Bayonet cap bulbs are also very common worldwide in applications where vibration may loosen screw-mount bulbs, such as automotive lighting and other small indicators, and in many flashlights. In many other countries the Edison screw (E) base is used for lighting.
Some bulbs may have slightly offset lugs to ensure they can be only inserted in one orientation, for example the 1157 automobile tail-light which has two different filaments to act as both a tail light and a brake light. In this bulb each filament has a different brightness and is connected to a separate contact on the bottom of the base; the two contacts are symmetrically positioned about the axis of the base, but the pins are offset so that the bulb can only be fitted in the correct orientation. Newer bulbs use a wedge base which can be inserted either way without complication. Some special-purpose bulbs, such as infra-red, have 3 pins 120 degrees apart to prevent them being used in any but the intended socket.
Bayonet bases or caps are often abbreviated to BA, often with a number after. The number refers to the diameter of the base (e.g., BA22 is a 22 mm diameter bayonet cap lamp). BA15, a 15 mm base, can also be referred to as SBC standing for small bayonet cap. The lower-case letter s or d specifies whether the bulb has single or double contacts. The entries from the table below pertain to IEC 60061 "Lamp caps and holders together with gauges for the control of interchangeability and safety" [5] and to DIN 49xxx. [lower-alpha 1]
Designation | IEC [5] | DIN [lower-alpha 2] | ANSI |
---|---|---|---|
BA7 | 7004-15-2 | 49710 | |
B8.4d & BX8.4d | 7004-140-1 | ||
BA9 | 7004-14-9 | ||
BA9s | 49715 | ||
BAX9s | 7004-8-1 | 49640-21 | |
BAY9s | 7004-9-1 | 49640-22 | |
BAU9s | 7004-150A-1 | ||
BAUZ9s | 7004-150B-1 | ||
BAW9s | 7004-149-1 | ||
BAZ9s | 7004-150-1 | ||
B15s | 49721 | ||
B15d | 7004-18-1 | 49721 | |
BA15 | 7004-11A-10 | 49720 | |
BAU15 | 7004-19-2 | ||
BAU15s | 49720-5 | ||
BAW15 | 7004-11E-1 | ||
BAX15d | 7004-18-1 | 49720-3 | |
BAY15d | 7004-11B-7 | 49720-2 | |
BAZ15 | 7004-11C-3 | ||
BAZ15d | 49720-4 | ||
BA15s-3(100°/130°) | 7004-11D-1 | ||
BA15d-3(100°/130°) | 7004-173-1 | ||
BA20 | 7004-12-7 | 49730 | |
BA21-3(120°) | 7004-13-4 | ||
B22s | 49740 | ||
B22d | 7004-10-7 | 49740 | |
B22d-3(90°/135°)/25x26 | 7004-10A-2 | ||
BY22d | 7004-17-3 |
These are the available sizes in the UK: [7]
Designation | Alternative designation | Contacts | Dimension, etc. |
---|---|---|---|
BA5s | 1 | 5 mm | |
BA7s | 1 | 7 mm, elongated pins | |
BAX9s | 1 | 9 mm, radially offset pins | |
BA9s | Miniature bayonet cap (MBC) | 1 | 9 mm |
BA15d | Small bayonet cap (SBC) | 2 | 15 mm |
BAY15d (P21/5W, 1157) | 2 | 15 mm, axially offset pins | |
BAX15s | 1 | 15 mm, radially offset pins | |
BA15s (P21W/1156/R5W/R10W) | Single centre contact (SCC) | 1 | 15 mm |
BA20s | 1 | 20 mm | |
BA20d | 2 | 20 mm | |
BA21d | 2 | 21 mm | |
B21-4 | 21 mm 4 pin | ||
BA22d | Bayonet cap (BC) | 2 | 22 mm |
BC-3 | Bayonet cap (BC) | 2 | 22 mm 3 bayonet pins |
B22d-3 | 2 | 22 mm double ended (railway) | |
BX22d | 2 | 22 mm |
Of these, only the BC (BA22d, often abbreviated as B22) is widely used in homes. Formerly, some linear fluorescent lamps in the UK used BA22d end caps, owing to material shortages arising from the Second World War, which prevented the development of the bi-pin cap design that was becoming commonplace elsewhere in the world; notably, in the United States. Production of these lamps continued until the early 1980s, although manufacturers had produced adaptors that permitted bi-pin lamps being used in older luminaires (equipped with bayonet lamp holders) since the 1960s. The BA20d (sometimes called a Bosch fitting) was once a common automotive (twin filament) headlamp fitting but has largely been superseded by more modern, higher-rated H-series sockets and is only used for some lower-powered applications such as combined automotive tail and stop lamps.
In Japan, the JIS C 8310 “hook ceiling” bayonet mount is quite common. It is designed to both provide power and carry the weight of a lamp. A similar concept existed in BS 7001 as the slide-in “luminaire-supporting coupler” (LSC), but its prominence is unknown.
Many cameras with interchangeable lenses use a bayonet lens mount to allow lenses to be changed rapidly and locked accurately in position. Camera lens mounts usually employ stronger flattened tabs rather than pins, though their function is the same.
A bayonet mount is often used to mate a cylinder with a base in cylindrical packaging such as that for CD spindles.
The BNC connector is a miniature quick connect/disconnect radio frequency connector used for coaxial cable. It is designed to maintain the same characteristic impedance of the cable, with 50 ohm and 75 ohm types being made. It is usually applied for video and radio frequency connections up to about 2 GHz and up to 500 volts. The connector has a twist to lock design with two lugs in the female portion of the connector engaging a slot in the shell of the male portion. The type was introduced on military radio equipment in the 1940s and has since become widely applied in radio systems, and is a common type of video connector. Similar radio-frequency connectors differ in dimensions and attachment features, and may allow for higher voltages, higher frequencies, or three-wire connections.
Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between parts of an electrical circuit, or between different electrical circuits, thereby joining them into a larger circuit. Most electrical connectors have a gender – i.e. the male component, called a plug, connects to the female component, or socket. The connection may be removable, require a tool for assembly and removal, or serve as a permanent electrical joint between two points. An adapter can be used to join dissimilar connectors.
The DIN connector is an electrical connector that was standardized by the Deutsches Institut für Normung (DIN), the German Institute for Standards, in the mid 1950's, initial with 3 pins for mono, but when stereo connections and gear appeared in late 1950's, versions with 5 pins or more were launched. The male DIN connectors (plugs) feature a 13.2 mm diameter metal shield with a notch that limits the orientation in which plug and socket can mate. The range of DIN connectors, different only in the configuration of the pins, have been standardized as DIN 41524 / IEC/DIN EN 60130-9 ; DIN 45322 ; DIN 45329 / IEC/DIN EN 60130–9 ; and DIN 45326 / IEC/DIN EN 60130-9.
The Electricity Supply Board is a state owned electricity company operating in the Republic of Ireland. While historically a monopoly, the ESB now operates as a commercial semi-state concern in a "liberalised" and competitive market. It is a statutory corporation whose members are appointed by the government of Ireland.
IEC 60309 is a series of international standards from the International Electrotechnical Commission (IEC) for "plugs, socket-outlets and couplers for industrial purposes". They are also referred to as "pin & sleeve" connectors in North America or as "CeeForm" connectors in the entertainment industry. The maximum voltage allowed by the standard is 1000 V DC or AC; the maximum current, 800 A; and the maximum frequency, 500 Hz. The ambient temperature range is −25 °C to 40 °C.
Industrial and multiphase plugs and sockets provide a connection to the electrical mains rated at higher voltages and currents than household plugs and sockets. They are generally used in polyphase systems, with high currents, or when protection from environmental hazards is required. Industrial outlets may have weatherproof covers, waterproofing sleeves, or may be interlocked with a switch to prevent accidental disconnection of an energized plug. Some types of connectors are approved for hazardous areas such as coal mines or petrochemical plants, where flammable gas may be present.
Tube sockets are electrical sockets into which vacuum tubes can be plugged, holding them in place and providing terminals, which can be soldered into the circuit, for each of the pins. Sockets are designed to allow tubes to be inserted in only one orientation. They were used in most tube electronic equipment to allow easy removal and replacement. When tube equipment was common, retailers such as drug stores had vacuum tube testers, and sold replacement tubes. Some Nixie tubes were also designed to use sockets.
In electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female. The female connector is generally a receptacle that receives and holds the male connector. Alternative terminology such as plug and socket or jack are sometimes used, particularly for electrical connectors.
A parabolic aluminized reflector lamp is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights.
Edison screw (ES) is a standard lightbulb socket for electric light bulbs. It was developed by Thomas Edison (1847–1931), patented in 1881, and was licensed in 1909 under General Electric's Mazda trademark. The bulbs have right-hand threaded metal bases (caps) which screw into matching threaded sockets. For bulbs powered by AC current, the thread is generally connected to neutral and the contact on the bottom tip of the base is connected to the "live" phase.
A multifaceted reflector light bulb is a reflector housing format for halogen as well as some LED and fluorescent lamps. MR lamps were originally designed for use in slide projectors, but see use in residential lighting and retail lighting as well. They are suited to applications that require directional lighting such as track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting, and bicycle headlights. MR lamps are designated by symbols such as MR16 where the diameter is represented by numerals indicating units of eighths of an inch. Common sizes for general lighting are MR16 and MR11, with MR20 and MR8 used in specialty applications. Many run on low voltage rather than mains voltage alternating current so require a power supply.
A bipin or bi-pin is a type of lamp fitting. They are included in the IEC standard "IEC 60061 Lamp caps and holders together with gauges for the control of interchangeability and safety". They are used on many small incandescent light bulbs, and for starters on some types of fluorescent lights.
A coaxial power connector is an electrical power connector used for attaching extra-low voltage devices such as consumer electronics to external electricity. Also known as barrel connectors, concentric barrel connectors or tip connectors, these small cylindrical connectors come in an enormous variety of sizes.
A wedge base is a type of electrical connector used as a fitting for small light bulbs. It is similar to the bi-pin connector, except that the two "pins" are the same wires that extend into the bulb, and the wires are bent up onto the sides of the base, where they make contact with the socket. The wires are usually inserted into a plastic base that the bulb is mounted in, and which is often narrower at the tip than at the bulb, giving it a wedge shape and usually ensuring a tight connection, depending on manufacturing tolerances. Some bulbs have no plastic base, and the wires are simply bent up to the sides of the bulb's glass base.
A 3-way lamp, also known as a tri-light, is a lamp that uses a 3-way light bulb to produce three levels of light in a low-medium-high configuration. A 3-way lamp requires a 3-way bulb and socket, and a 3-way switch.
A lightbulb socket, lightbulb holder,light socket, lamp socket or lamp holder is a device which mechanically supports and provides electrical connections for a compatible electric lamp base. Sockets allow lamps to be safely and conveniently replaced (re-lamping). There are many different standards for lampholders, including early de facto standards and later standards created by various standards bodies. Many of the later standards conform to a general coding system in which a socket type is designated by a letter or abbreviation followed by a number.
The A-series light bulb is the "classic" glass light bulb shape that has been the most commonly used type for general lighting service (GLS) applications since the early 20th century. It has a pear-like shape and is typically fitted to either an Edison screw or a bayonet cap base. The number that follows the "A" designation indicates the nominal major diameter of the bulb, either in one-eighth inch units in North America or in millimeters in the rest of the world.
A GU24 lamp fitting is a bi-pin connector for compact fluorescent lamps (CFL) or LED lamps that uses a bayonet mount–like twist-lock bi-pin connector instead of the Edison screw fitting used on many CFLs, LED lamps and incandescent light bulbs. The design was initiated by the U.S. EPA and the Lighting Research Center in 2004, in order to facilitate the deployment of compact fluorescent light bulbs with replaceable ballasts.
There are approximately 20 types in common use around the world, such as AC power plugs and sockets, and many obsolete socket types which are still found in older buildings.
Replaces DIN 49610:1986-10 , DIN 49612:1984-08 , etc.