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Eccentric (mechanism)
In mechanical engineering, an eccentric is a circular disk (''eccentric sheave'') solidly fixed to a rotating axle with its centre offset from that of the axle (hence the word "eccentric", out of the center). It is used most often in steam engines, and used to convert rotary motion into linear reciprocating motion to drive a sliding valve or pump ram. To do so, an eccentric usually has a groove at its circumference closely fitted a circular collar (''eccentric strap''). An attached ''eccentric rod'' is suspended in such a way that its other end can impart the required reciprocating motion. A return crank fulfills the same function except that it can only work at the end of an axle or on the outside of a wheel whereas an eccentric can also be fitted to the body of the axle between the wheels. Unlike a cam, which also converts rotary into linear motion at almost any rate of acceleration and deceleration, an eccentric or return crank can only impart an approximation of simple harmoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentric & Rod 003
Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a vertex in a graph * Eccentricity (mathematics), a parameter associated with every conic section Orbital mechanics * Orbital eccentricity, in astrodynamics, a measure of the non-circularity of an orbit * Eccentric anomaly, the angle between the direction of periapsis and the current position of an object on its orbit * Eccentricity vector, in celestial mechanics, a dimensionless vector with direction pointing from apoapsis to periapsis * Eccentric, a type of deferent, a circle or sphere used in obsolete epicyclical systems to carry a planet around the Earth or Sun Other uses in science and technology * Eccentric (mechanism), a wheel that rotates on an axle that is displaced from the focus of the circle described by the wheel * Horizontal ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem Bicycle
A tandem bicycle or twin is a form of bicycle (occasionally a tricycle) designed to be ridden by more than one person. The term tandem refers to the seating arrangement (fore to aft, not side by side), not the number of riders. Patents related to tandem bicycles date from the mid 1880s. Tandems can reach higher speeds than the same riders on single bicycles, and tandem bicycle racing exists. As with bicycles for single riders, there are many variations that have been developed over the years. Terminology The term tandem refers to the seating arrangement (fore to aft, not side by side), not the number of riders. A bike with two riders side by side is called a sociable. Tandem bicycles are sometimes called "Daisy Bells". This is in reference to "Daisy Bell (Bicycle Built for Two)" which is a popular song, written in 1892 by British songwriter Harry Dacre, with the well-known chorus, "Daisy, Daisy / Give me your answer, do. / I'm half crazy / all for the love of you", ending wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Set Screw
In American English, a set screw is a screw that is used to secure an object, by pressure and/or friction, within or against another object, such as fixing a pulley or gear to a shaft. A set screw is normally used without a nut (which distinguishes it from a bolt), being screwed instead in a threaded hole drilled in only one of the two objects to be secured. A set screw is often headless and threaded along its entire length, so that it will sit entirely inside that hole; in which case it may be called a grub screw or blind screw. Once fully and firmly screwed into the first object, the projecting tip of the set screw presses hard against the second object, acting like a clamp. The second object may have a machined detent (recess) to ensure that it cannot slide under the tip of the screw. On a shaft, this may be simply a flattened area. A set screw may have any type of drive, such as hex or square head, slot, or recessed --- cross (Phillips), hex (Allen), star (Torx), or sq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wedge
A wedge is a triangular shaped tool, and is a portable inclined plane, and one of the six simple machines. It can be used to separate two objects or portions of an object, lift up an object, or hold an object in place. It functions by converting a force applied to its blunt end into forces perpendicular (normal) to its inclined surfaces. The mechanical advantage of a wedge is given by the ratio of the length of its slope to its width..''McGraw-Hill Concise Encyclopedia of Science & Technology'', Third Ed., Sybil P. Parker, ed., McGraw-Hill, Inc., 1992, p. 2041. Although a short wedge with a wide angle may do a job faster, it requires more force than a long wedge with a narrow angle. The force is applied on a flat, broad surface. This energy is transported to the pointy, sharp end of the wedge, hence the force is transported. The wedge simply transports energy in the form of friction and collects it to the pointy end, consequently breaking the item. History Wedges have exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottom Bracket
The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals A pedal (from the Latin '' pes'' ''pedis'', "foot") is a lever designed to be operated by foot and may refer to: Computers and other equipment * Footmouse, a foot-operated computer mouse * In medical transcription, a pedal is used to control p ... attach to the cranks. Bottom bracket bearings fit inside the Bicycle frame#Bottom bracket shell, bottom bracket shell, which connects the Bicycle frame#Seat tube, seat tube, Bicycle frame#Down tube, down tube and Bicycle frame#Chain stays, chain stays as part of the bicycle frame. The term "bracket" refers to the tube fittings that are used to hold frame tubes together in Lugged steel frame construction, lugged steel frames which also form the shell that contains the spi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Derailleur
Shimano 600 front derailleur (1980) A derailleur is a variable-ratio bicycle gearing system consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another. Modern front and rear derailleurs typically consist of a moveable chain-guide that is operated remotely by a Bowden cable attached to a shifter mounted on the down tube, handlebar stem, or handlebar. When a rider operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. Etymology ''Dérailleur'' is a French word, derived from the derailment of a train from its tracks. Its first recorded use was 1930. History A modern road bicycle drivetrain with front and rear derailleurs Various derailleur systems were designed and built in the late 19th century. One example is the Protean two-speed derailleur available on the Whippet safety bicycle. The French bicycle tou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropout (bicycle Part)
A fork end, fork-end, or forkend is a slot in a bicycle frame or bicycle fork where the axle of a bicycle wheel is attached. A dropout is a type of fork end that allows the rear wheel to be removed without first derailing the chain. Track bicycle frames have track fork ends, on which the opening faces rearwards. Because they do not have dropouts, the chain must be derailed from the sprocket before the rear wheel can be removed from a typical track bike. Some single-speed bicycles intended for street or trail use are also equipped with track fork ends instead of dropouts. On bicycles that do not have a derailleur or other chain tensioning device, rear ''horizontal dropouts'' allow adjustment of chain tension, and can accommodate a range of chain lengths or cog sizes. They were standard on most older derailleur bicycles from before the 1990s. An older derailleur-equipped bicycle with horizontal dropouts can be readily converted into singlespeed, fixed gear or to use an internally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hub Gear
A hub gear, internal-gear hub, internally geared hub or just gear hub is a gear ratio changing system commonly used on bicycles that is implemented with planetary or epicyclic gears. The gears and lubricants are sealed within the shell of the hub gear, in contrast with derailleur gears where the gears and mechanism are exposed to the elements. Changing the gear ratio was traditionally accomplished by a shift lever connected to the hub with a Bowden cable, and twist-grip style shifters have become common. Hub gear systems generally have a long and largely maintenance-free life though some are not suitable for high-stress use in competitions or hilly, off-road conditions. Many commuter or urban cycles such as European city bikes are now commonly fitted with 7-speed gear-hubs and 8-speed systems are becoming increasingly available. Older or less costly utility bicycles often use 3-speed gear-hubs, such as in bicycle sharing systems. Many folding bicycles use 3-speed gear-hubs. Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Brake
A bicycle brake reduces the speed of a bicycle or prevents it from moving. The three main types are: rim brakes, disc brakes, and drum brakes. Most bicycle brake systems consist of three main components: a mechanism for the rider to apply the brakes, such as brake levers or pedals; a mechanism for transmitting that signal, such as Bowden cables, hydraulic hoses, rods, or the bicycle chain; and the brake mechanism itself, a caliper or drum, to press two or more surfaces together in order to convert, via friction, kinetic energy of the bike and rider into thermal energy to be dissipated. History Karl Drais included a pivoting brake shoe that could be pressed against the rear iron tyre of his 1817 . This was continued on the earliest bicycles with pedals, such as the boneshaker, which were fitted with a spoon brake to press onto the rear wheel. The brake was operated by a lever or by a cord connecting to the handlebars. The rider could also slow down by resisting the pedals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-speed Bicycle
A single-speed bicycle is a type of bicycle with a single gear ratio. These bicycles are without derailleur gears, hub gearing or other methods for varying the gear ratio of the bicycle. There are many types of modern single speed bicycles; BMX bicycles, most bicycles designed for children, cruiser type bicycles, classic commuter bicycles, unicycles, bicycles designed for track racing, fixed-gear road bicycles, and single-speed mountain and cyclocross bikes. Although most fixed-gear bicycles (fixies) are technically single speed, the term single-speed generally refers to a single gear ratio bicycle with a freewheel mechanism to allow it to coast. Vis-à-vis multi-speed bicycles Advantages A single-speed bicycle is generally cheaper, lighter, and mechanically simpler than its multi-geared equivalent. Without derailleurs or other gearing systems, there are fewer parts on the bicycle that require maintenance, making this type of cycle useful for city commuting in all weath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentric Bottom Bracket
Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a vertex in a graph * Eccentricity (mathematics), a parameter associated with every conic section Orbital mechanics * Orbital eccentricity, in astrodynamics, a measure of the non-circularity of an orbit * Eccentric anomaly, the angle between the direction of periapsis and the current position of an object on its orbit * Eccentricity vector, in celestial mechanics, a dimensionless vector with direction pointing from apoapsis to periapsis * Eccentric, a type of deferent, a circle or sphere used in obsolete epicyclical systems to carry a planet around the Earth or Sun Other uses in science and technology * Eccentric (mechanism), a wheel that rotates on an axle that is displaced from the focus of the circle described by the wheel * Horizontal ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering branches. Mechanical engineering requires an understanding of core areas including mechanics, dynamics, thermodynamics, materials science, structural analysis, and electricity. In addition to these core principles, mechanical engineers use tools such as computer-aided design (CAD), computer-aided manufacturing (CAM), and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, aircraft, watercraft, robotics, medical devices, weapons, and others. Mechanical engineering emerged as a field during the Industrial Revolution in Europe in the 18th century; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
