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Clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). In these devices, one shaft is typically attached to an engine or other power unit (the driving member), while the other shaft (the driven member) provides output power for work. Typically the motions involved are rotary, but linear clutches also exist. In a motor vehicle, the clutch acts as a mechanical linkage between the engine and transmission, and briefly disconnects, or separates the engine from the transmission system. This disconnects the drive wheels whenever the clutch pedal is depressed, allowing the driver to smoothly change gears. In a torque-controlled drill, for instance, one shaft is driven by a motor, and the other drives a drill chuck. The clutch connects the two shafts so they may be locked together and spin at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission (mechanics)
Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differential, and final drive shafts. In the United States the term is sometimes used in casual speech to refer more specifically to the gearbox alone, and detailed usage differs. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and where different rotational speeds and torques are adapted. Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as the speed varies. This switching may be done manually (by the operator) or automatically (by a control unit). Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-synchronous Transmission
A non-synchronous transmission, also called a crash gearbox, is a form of manual transmission based on gears that do not use synchronizing mechanisms. They require the driver to manually synchronize the transmission's input speed (engine RPM) and output speed (driveshaft speed). Non-synchronous transmissions are found primarily in various types of industrial machinery; such as tractors and semi-tractors. Non-synchronous manual transmissions are also found on motorcycles, in the form of constant-mesh sequential manual transmissions. Prior to the 1950s and 1960s, most cars used constant-mesh (and also sliding-mesh) but non-synchronous transmissions. History Most early automobiles were rear-engined, using a single-speed transmission and belt-drive to power the rear wheels. In 1891, the French Panhard et Levassor automobile used a three-speed manual transmission and is considered to have set the template for multi-speed manual transmissions in motor vehicles. This transmiss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchromesh
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom, and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually a foot pedal for cars or a hand lever for motorcycles). Early automobiles used ''sliding-mesh'' manual transmissions with up to three forward gear ratios. Since the 1950s, ''constant-mesh'' manual transmissions have become increasingly commonplace and the number of forward ratios has increased to 5-speed and 6-speed manual transmissions for current vehicles. The alternative to a manual transmission is an automatic transmission; common types of automatic transmissions are the hydraulic automatic transmission (AT), and the continuously variable transmission (CVT), whereas the automated manual transmission (AMT) and dual-clutch transmis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dog Clutch
A dog clutch (also known as a positive clutch or dog gears) is a type of clutch that couples two rotating shafts or other rotating components by engagement of interlocking teeth or dogs rather than by friction. The two parts of the clutch are designed such that one will push the other, causing both to rotate at the same speed and will never slip. In engineering, a " dog" is a tool or device used to lock two components in relation to each other. Dog clutches are used where slip is undesirable and/or the clutch is not used to control torque. Without slippage, dog clutches are not affected by wear in the same way that friction clutches are, but result in shock when shafts of different speeds are engaged. For this reason they are best used when sudden starting action is acceptable and the inertia of the system is small. Dog clutches are used inside constant-mesh manual transmissions to lock different gears to the rotating input and output shafts. A synchromesh arrangement ensures sm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flywheel
A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, assuming the flywheel's moment of inertia is constant (i.e., a flywheel with fixed mass and second moment of area revolving about some fixed axis) then the stored (rotational) energy is directly associated with the square of its rotational speed. Since a flywheel serves to store mechanical energy for later use, it is natural to consider it as a kinetic energy analogue of an electrical inductor. Once suitably abstracted, this shared principle of energy storage is described in the generalized concept of an accumulator. As with other types of accumulators, a flywheel inherently smooths sufficiently small deviations in the power output of a system, thereby effectively playing the role of a low-pass filter with respect to the mechanical veloc ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick G
Frederick may refer to: People * Frederick (given name), the name Nobility Anhalt-Harzgerode * Frederick, Prince of Anhalt-Harzgerode (1613–1670) Austria * Frederick I, Duke of Austria (Babenberg), Duke of Austria from 1195 to 1198 * Frederick II, Duke of Austria (1219–1246), last Duke of Austria from the Babenberg dynasty * Frederick the Fair (Frederick I of Austria (Habsburg), 1286–1330), Duke of Austria and King of the Romans Baden * Frederick I, Grand Duke of Baden (1826–1907), Grand Duke of Baden * Frederick II, Grand Duke of Baden (1857–1928), Grand Duke of Baden Bohemia * Frederick, Duke of Bohemia (died 1189), Duke of Olomouc and Bohemia Britain * Frederick, Prince of Wales (1707–1751), eldest son of King George II of Great Britain Brandenburg/Prussia * Frederick I, Elector of Brandenburg (1371–1440), also known as Frederick VI, Burgrave of Nuremberg * Frederick II, Elector of Brandenburg (1413–1470), Margrave of Brandenburg * Frederick William, E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleprinter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering, though teleprinters were not used for telegraphy until 1887 at the earliest. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage (either from typed input or from data received from a remote source) and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media. These included a simple pair of wires; dedicated non-switched telephone circuits (leased lines); switched ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Metal Typesetting
In printing and typography, hot metal typesetting (also called mechanical typesetting, hot lead typesetting, hot metal, and hot type) is a technology for typesetting text in letterpress printing. This method injects molten type metal into a mold that has the shape of one or more glyphs. The resulting sorts or slugs are later used to press ink onto paper. Normally the typecasting machine would be controlled by a keyboard or by a paper tape. It was the standard technology used for mass-market printing from the late nineteenth century until the arrival of phototypesetting and then electronic processes in the 1950s to 1980s. History Hot metal typesetting was developed in the late nineteenth century as a development of conventional cast metal type. The technology had several advantages: it reduced labour since type sorts did not need to be slotted into position manually, and each casting created crisp new type for each printing job. In the case of Linotype machines, each line w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tabulating Machine
The tabulating machine was an electromechanical machine designed to assist in summarizing information stored on punched cards. Invented by Herman Hollerith, the machine was developed to help process data for the 1890 U.S. Census. Later models were widely used for business applications such as accounting and inventory control. It spawned a class of machines, known as unit record equipment, and the data processing industry. The term " Super Computing" was used by the ''New York World'' newspaper in 1931 to refer to a large custom-built tabulator that IBM made for Columbia University. 1890 census The 1880 census had taken eight years to process. Since the U.S. Constitution mandates a census every ten years to apportion both congressional representatives and direct taxes among the states, a combination of larger staff and faster-recording systems was required. In the late 1880s Herman Hollerith, inspired by conductors using holes punched in different positions on a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crankshaft
A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting rods. The crankpins are also called ''rod bearing journals'', and they rotate within the "big end" of the connecting rods. Most modern crankshafts are located in the engine block. They are made from steel or cast iron, using either a forging, casting or machining process. Design The crankshaft located within the engine block, held in place via main bearings which allow the crankshaft to rotate within the block. The up-down motion of each piston is transferred to the crankshaft via connecting rods. A flywheel is often attached to one end of the crankshaft, in order to smoothen the power delivery and reduce vibration. A crankshaft is subjected to enormous stresses, in some cases more than per cylinder. Crankshafts for sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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