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Retro-direct
Retro-direct is a gearing mechanism used on some bicycles in the early 20th century, which provides a second gear ratio when pedaled backwards. History Retro-direct was developed by French inventor Paul de Martin de Viviés (1833–1911). An early two-chain version was patented by in 1869 by Barberon and Meunier. A single-chain version was patented in 1903 by the bicycle manufacturer Hirondelle. Some hobbyists have converted modern bicycles to use retro-direct gearing. Technical details In the single-chain system, the chain runs from the top of a chainring attached to the cranks to the top of a sprocket attached to the rear wheel hub with a freewheel Freewheel mechanism In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An ..., as with most bicycle chain drives. The chain then, usually, wraps around the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retro-direct
Retro-direct is a gearing mechanism used on some bicycles in the early 20th century, which provides a second gear ratio when pedaled backwards. History Retro-direct was developed by French inventor Paul de Martin de Viviés (1833–1911). An early two-chain version was patented by in 1869 by Barberon and Meunier. A single-chain version was patented in 1903 by the bicycle manufacturer Hirondelle. Some hobbyists have converted modern bicycles to use retro-direct gearing. Technical details In the single-chain system, the chain runs from the top of a chainring attached to the cranks to the top of a sprocket attached to the rear wheel hub with a freewheel Freewheel mechanism In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An ..., as with most bicycle chain drives. The chain then, usually, wraps around the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Gearing
Bicycle gearing is the aspect of a bicycle drivetrain that determines the relation between the cadence, the rate at which the rider pedals, and the rate at which the drive wheel turns. On some bicycles there is only one gear and, therefore, the gear ratio is fixed, but most modern bicycles have multiple gears and thus multiple gear ratios. A shifting mechanism allows selection of the appropriate gear ratio for efficiency or comfort under the prevailing circumstances: for example, it may be comfortable to use a high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. Different gear ratios and gear ranges are appropriate for different people and styles of cycling. A cyclist's legs produce power optimally within a narrow pedalling speed range, or cadence. Gearing can be optimized to use this narrow range as efficiently as possible. As in other types of transmissions, the gear ratio is closely related to the mechanical ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retro Fahrrad
Retro style is imitative or consciously derivative of lifestyles, trends, or art forms from history, including in music, modes, fashions, or attitudes. In popular culture, the "nostalgia cycle" is typically for the two decades that begin 20–30 years ago. Definition The term ''retro'' has been in use since 1972 to describe on the one hand, new artifacts that self-consciously refer to particular modes, motifs, techniques, and materials of the past. But on the other hand, many people use the term to categorize styles that have been created in the past. Retro style refers to new things that display characteristics of the past. Unlike the historicism of the Romantic generations, it is mostly the recent past that retro seeks to recapitulate, focusing on the products, fashions, and artistic styles produced since the Industrial Revolution, the successive styles of Modernity. The English word ''retro'' derives from the Latin prefix ''retro'', meaning backwards, or in past times. In Fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanism (technology)
In engineering, a mechanism is a device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which may include: * Gears and gear trains; * Belts and chain drives; * Cams and followers; * Linkages; * Friction devices, such as brakes or clutches; * Structural components such as a frame, fasteners, bearings, springs, or lubricants; * Various machine elements, such as splines, pins, or keys. The German scientist Franz Reuleaux defines ''machine'' as "a combination of resistant bodies so arranged that by their means the mechanical forces of nature can be compelled to do work accompanied by certain determinate motion". In this context, his use of ''machine'' is generally interpreted to mean ''mechanism''. The combination of force and movement defines power, and a mechanism manages power to achieve a desired set of forces and movement. A mechanism is usually a piece of a larger process, known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycles
A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bicycles were introduced in the 19th century in Europe. By the early 21st century, more than 1 billion were in existence. These numbers far exceed the number of cars, both in total and ranked by the number of individual models produced. They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, bicycle racing, and bicycle stunts. The basic shape and configuration of a typical upright or "safety bicycle", has changed little since the first chain-driven model was developed around 1885. However, many details have been improved, especially since the advent of modern ... [...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] |
Crankset
The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called ''chainrings'' or ''chainwheels'' attached to the '' cranks'', ''arms'', or ''crankarms'' to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain. Parts Cranks The two ''cranks'', one on each side and usually mounted 180° apart, connect the bottom bracket axle to the pedals. Lengths Bicycle cranks can vary in length to accommodate different sized riders and different types of cycling. Crank length is measured from the center of the pedal spindle to the center of the bottom bracket spindle or axle. The larger bicycle component manufacturers typically offer cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicycle Wheel
A bicycle wheel is a wheel, most commonly a wire wheel, designed for a bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels. Bicycle wheels are typically designed to fit into the bicycle frame, frame and bicycle fork, fork via Dropout (bicycle part), dropouts, and hold bicycle tires. Invention The first wheel to use the tension in wire wheel, metal spokes was invented by George Cayley, Sir George Cayley to achieve lightness in his 1853 glider. Construction The first bicycle wheels followed the traditions of carriage building: a wooden hub, a fixed steel axle (the bearings were located in the fork ends), wooden spokes and a shrink fitted iron tire. A typical modern wheel has a metal hub, wire tension spokes and a metal or carbon fiber rim which holds a pneumatic rubber tire. Hub A hub is the center part of a bicycle wheel. It consists of an axle, bearing (mechanical), bearings and a hub shell. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freewheel
Freewheel mechanism In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated. The condition of a driven shaft spinning faster than its driveshaft exists in most bicycles when the rider stops pedaling. In a fixed-gear bicycle, without a freewheel, the rear wheel drives the pedals around. An analogous condition exists in an automobile with a manual transmission going downhill, or any situation where the driver takes their foot off the gas pedal, closing the throttle: the wheels drive the engine, possibly at a higher RPM. In a two-stroke engine, this can be catastrophic—as many two stroke engines depend on a fuel/oil mixture for lubrication, a shortage of fuel to the engine starves oil from the cylinders, and the pistons can soon seize, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
