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Chains
A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A chain may consist of two or more links. Chains can be classified by their design, which can be dictated by their use: * Those designed for lifting, such as when used with a hoist; for pulling; or for securing, such as with a bicycle lock, have links that are torus shaped, which make the chain flexible in two dimensions (the fixed third dimension being a chain's length). Small chains serving as jewellery are a mostly decorative analogue of such types. * Those designed for transferring power in machines have links designed to mesh with the teeth of the sprockets of the machine, and are flexible in only one dimension. They are known as roller chains, though there are also non-roller chains such as block chains. Two distinct chains can be co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainsaw
A chainsaw (or chain saw) is a portable gasoline-, electric-, or battery-powered saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. It is used in activities such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression, and harvesting of firewood. Chainsaws with specially designed bar-and-chain combinations have been developed as tools for use in chainsaw art and chainsaw mills. Specialized chainsaws are used for cutting concrete during construction developments. Chainsaws are sometimes used for cutting ice; for example, ice sculpture and winter swimming in Finland. History In surgery The origin of chain saws in surgery is debated. A "flexible saw", consisting of a fine serrated link chain held between two wooden handles, was pioneered in the late 18th century (c. 1783–1785) by two Scottish doctors, John Aitken and James Jeffray, for symphysiotomy and excision of diseased bone, respectively. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roller Chain
Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, cars, motorcycles, and bicycles. It consists of a series of short cylindrical rollers held together by side links. It is driven by a toothed wheel called a sprocket. It is a simple, reliable, and efficientAs much as 98% efficient under ideal conditions, according to means of power transmission. Sketches by Leonardo da Vinci in the 16th century show a chain with a roller bearing. In 1800, James Fussell patented a roller chain on development of his balance lock and in 1880 Hans Renold patented a bush roller chain. Construction There are two types of links alternating in the bush roller chain. The first type is inner links, having two inner plates held together by two sleeves or bushings upon which rotate two rollers. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Chain
A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. History Obsolete chain designs previously used on bicycles included the block chain, the skip-link chain, and the Simpson lever chain. The first chains were of a simple, bushing-less design. These had inherent reliability problems and a bit more friction (and mechanical efficiency losses) than modern chains. With these limitations in mind, the Nevoigt brothers, of the German Diamant Bicycle Company, designed the roller chain in 1898, which uses bushings. More recently, the "bushingless roller chain" design has superseded the bushed chain. This design incorporates the bearing surface of the bushing into the inner side plate, with each plate creating half of the bushing. This reduces the number of parts needed to assemble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Drive
Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. Most often, the power is conveyed by a roller chain, known as the drive chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain putting mechanical force into the system. Another type of drive chain is the Morse chain, invented by the Morse Chain Company of Ithaca, New York, United States. This has inverted teeth. Sometimes the power is output by simply rotating the chain, which can be used to lift or drag objects. In other situations, a second gear is placed and the power is recovered by attaching shafts or hubs to this gear. Though drive chains are often simple oval loops, they can also go around corners by placi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Stopper
A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A chain may consist of two or more links. Chains can be classified by their design, which can be dictated by their use: * Those designed for lifting, such as when used with a hoist; for pulling; or for securing, such as with a bicycle lock, have links that are torus shaped, which make the chain flexible in two dimensions (the fixed third dimension being a chain's length). Small chains serving as jewellery are a mostly decorative analogue of such types. * Those designed for transferring power in machines have links designed to mesh with the teeth of the sprockets of the machine, and are flexible in only one dimension. They are known as roller chains, though there are also non-roller chains such as block chains. Two distinct chains can be co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Of Office
A livery collar or chain of office is a collar or heavy chain, usually of gold, worn as insignia of office or a mark of fealty or other association in Europe from the Middle Ages onwards. One of the oldest and best-known livery collars is the Collar of Esses, which has been in continuous use in England since the 14th century. History Origins Various forms of livery were used in the Middle Ages to denote attachment to a great person by friends, servants, and political supporters. The collar, usually of precious metal, was the grandest form of these, usually given by the person the livery denoted to his closest or most important associates, but should not, in the early period, be seen as separate from the wider phenomenon of livery badges, clothes and other forms. From the collar hung a badge or device indicating the person the livery related to; the most important part of the ensemble for contemporaries. Equally gold collars that had no livery connotations were worn. Livery co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewelry Chain
Fine metal chains are used in jewellery to encircle parts of the body, namely the neck, wrists and ankles, and they also serve as points to hang decorative charms and pendants. Unlike industrial or chains for other purposes, jewellery chains or ''body chains'' are designed for aesthetic purposes. Material Jewellery chains are typically made from precious metals, mainly gold and silver. Platinum, palladium and steel may also be used. These metals are used because they are not very reactive, keep both their intricate shape and their strength, and require only minimal maintenance to keep their shine. Small lever mechanisms called findings serve as fastenings to enable the chain to be undone and redone. Styles File:Silver Jewellery Chain.jpg, Trace: Often the simplest style of chain. The links in a trace chain are typically uniform in breadth and thickness, and can be very delicate, especially in finer widths. File:Rolo chain.jpg, Rolo: The links of a rolo chain are usually ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Lock
A bicycle lock is a security device used to deter bicycle theft, either by simply locking one of the wheels or by fastening the bicycle to a fixed object, e.g., a bike rack. Quick-release levers, as used on some bicycle wheels and seatpost fasteners, are a security vulnerability, because they allow the wheels and saddle to be easily removed. Unless such easily removable components are secured while the bicycle is unattended, they are vulnerable to theft. Sensible locking strategies address this by locking these components in addition to the frame, or by taking the vulnerable components, such as quick-release front wheels, away from the bicycle. Locking devices vary in size and security, the most secure tending to be the largest, heaviest and least portable. Thus, like other security equipment, bicycle locks must balance the competing interests of security, portability, and cost. Some are made of particularly expensive materials chosen for their acceptable strength and low density ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewellery
Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western perspective, the term is restricted to durable ornaments, excluding flowers for example. For many centuries metal such as gold often combined with gemstones, has been the normal material for jewellery, but other materials such as glass, shells and other plant materials may be used. Jewellery is one of the oldest types of archaeological artefact – with 100,000-year-old beads made from ''Nassarius'' shells thought to be the oldest known jewellery.Study reveals 'oldest jewellery' , '' |
Sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth except for timing pulleys used with toothed belts. Sprockets are used in bicycles, motorcycles, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc. Perhaps the most common form of sprocket may be found in the bicycle, in which the pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket and chain mechanism, a practice la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimension
In physics and mathematics, the dimension of a Space (mathematics), mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any Point (geometry), point within it. Thus, a Line (geometry), line has a dimension of one (1D) because only one coordinate is needed to specify a point on itfor example, the point at 5 on a number line. A Surface (mathematics), surface, such as the Boundary (mathematics), boundary of a Cylinder (geometry), cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on itfor example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the Euclidean plane, plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces. In classical mechanics, space and time are different categ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omega Chain
An omega chain or omega necklace is a pseudo-chain made by assembling metallic plates on a wire or woven mesh. The plates give the appearance of links in a chain. The embedded wire provides the strength, so the plates can be designed to please the eye. See also *Persian weave Persian weave is a method of weave used in jewelry and other art forms, using jump rings. The Persian family of weaves is a chainmail Chain mail (properly called mail or maille but usually called chain mail or chainmail) is a type of armo ... References Types of jewellery {{Fashion-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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