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Wheel
A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a ship's wheel, steering wheel, potter's wheel, and flywheel. Common examples are found in transport applications. A wheel reduces friction by facilitating motion by rolling together with the use of Axle, axles. In order for wheels to rotate, a Moment (physics), moment needs to be applied to the wheel about its axis, either by way of gravity or by the application of another external force or torque. Using the wheel, Sumer, Sumerians invented a device that spins clay as a potter shapes it into the desired object. Terminology The English word '':wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steering Wheel
A steering wheel (also called a driving wheel (UK), a hand wheel, or simply wheel) is a type of steering control in vehicles. Steering wheels are used in most modern land vehicles, including all mass-production automobiles, buses, light and heavy trucks, as well as tractors. The steering wheel is the part of the steering system that is manipulated by the driver; the rest of the steering system responds to such driver inputs. This can be through direct mechanical contact as in recirculating ball or rack and pinion steering gears, without or with the assistance of hydraulic power steering, HPS, or as in some modern production cars with the assistance of computer-controlled motors, known as electric power steering. History Near the start of the 18th century, a large number of sea vessels appeared using the ship's wheel design, but historians are unclear when that approach to steering was first used. The first automobiles were steered with a tiller, but in 1894, Alfred Va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheel And Axle
The wheel and axle is a simple machine consisting of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other. The wheel and axle can be viewed as a version of the lever, with a drive force applied tangentially to the perimeter of the wheel, and a load force applied to the axle supported in a bearing, which serves as a fulcrum. History The Halaf culture of 6500–5100 BCE has been credited with the earliest depiction of a wheeled vehicle, but this is doubtful as there is no evidence of Halafians using either wheeled vehicles or even pottery wheels. One of the first applications of the wheel to appear was the potter's wheel, used by prehistoric cultures to fabricate clay pots. The earliest type, known as "tournettes" or "slow wheels", were known in the Middle East by the 5th millennium BCE. One of the earliest examples was discovered at Tepe Pardis, Iran, and dated to 5200–4700 BCE. These were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potter's Wheel
In pottery, a potter's wheel is a machine used in the shaping (known as throwing) of clay into round ceramic ware. The wheel may also be used during the process of trimming excess clay from leather-hard dried ware that is stiff but malleable, and for applying incised decoration or rings of colour. Use of the potter's wheel became widespread throughout the Old World but was unknown in the Pre-Columbian New World, where pottery was handmade by methods that included coiling and beating. A potter's wheel may occasionally be referred to as a "potter's lathe". However, that term is better used for another kind of machine that is used for a different shaping process, turning, similar to that used for shaping of metal and wooden articles. The pottery wheel is an important component to create arts and craft products. The techniques of jiggering and jolleying can be seen as extensions of the potter's wheel: in jiggering, a shaped tool is slowly brought down onto the plastic clay body t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axle
An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type axle is referred to as a ''spindle''. Terminology On cars and trucks, several senses of the word ''axle'' occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. Strictly speaking, a shaft which rotates with the wheel, being either bolted or splined in fixed relation to it, is called an ''axle'' or ''axle shaft''. However, in looser usage, an entire assembly including the surrounding axle housing (typically a casting) is als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axle
An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type axle is referred to as a ''spindle''. Terminology On cars and trucks, several senses of the word ''axle'' occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. Strictly speaking, a shaft which rotates with the wheel, being either bolted or splined in fixed relation to it, is called an ''axle'' or ''axle shaft''. However, in looser usage, an entire assembly including the surrounding axle housing (typically a casting) is als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proto-Indo-European Language
Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo-European exists. Far more work has gone into reconstructing PIE than any other proto-language, and it is the best understood of all proto-languages of its age. The majority of linguistic work during the 19th century was devoted to the reconstruction of PIE or its daughter languages, and many of the modern techniques of linguistic reconstruction (such as the comparative method) were developed as a result. PIE is hypothesized to have been spoken as a single language from 4500 BC to 2500 BC during the Late Neolithic to Early Bronze Age, though estimates vary by more than a thousand years. According to the prevailing Kurgan hypothesis, the original homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian steppe of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Machine
A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. Usually the term refers to the six classical simple machines that were defined by Renaissance scientists: * Lever * Wheel and axle * Pulley * Inclined plane * Wedge * Screw A simple machine uses a single applied force to do work against a single load force. Ignoring friction losses, the work done on the load is equal to the work done by the applied force. The machine can increase the amount of the output force, at the cost of a proportional decrease in the distance moved by the load. The ratio of the output to the applied force is called the ''mechanical advantage''. Simple machines can be regarded as the elementary "building blocks" of which all more complicated machines (sometimes called "compound machines") are composed. For example, wheels, levers, and pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesopotamia
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. Today, Mesopotamia occupies modern Iraq. In the broader sense, the historical region included present-day Iraq and Kuwait and parts of present-day Iran, Syria and Turkey. The Sumerians and Akkadians (including Assyrians and Babylonians) originating from different areas in present-day Iraq, dominated Mesopotamia from the beginning of written history () to the fall of Babylon in 539 BC, when it was conquered by the Achaemenid Empire. It fell to Alexander the Great in 332 BC, and after his death, it became part of the Greek Seleucid Empire. Later the Arameans dominated major parts of Mesopotamia (). Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It has been identi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may ''prevent'' a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, and transfer axial and radial loads from the source of the load to the structure supporting it. The simplest form of bearing, the ''plain bearing'', consists of a shaft rotating in a hole. Lubrication is used to reduce friction. In the ''ball bearing'' and ''roller bearing'', to reduce sliding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship's Wheel
A ship's wheel or boat's wheel is a device used aboard a water vessel to steer that vessel and control its course. Together with the rest of the steering mechanism, it forms part of the helm. It is connected to a mechanical, electric servo, or hydraulic system which alters the horizontal angle of the vessel's rudder relative to its hull. In some modern ships the wheel is replaced with a simple toggle that remotely controls an electro-mechanical or electro-hydraulic drive for the rudder, with a rudder position indicator presenting feedback to the helmsman. History Until the invention of the ship's wheel, the helmsman relied on a tiller—a horizontal bar fitted directly to the top of the rudder post—or a whipstaff—a vertical stick acting on the arm of the ship's tiller. Near the start of the 18th century, a large number of vessels appeared using the ship's wheel design, but historians are unclear when the approach was first used. Design A traditional ship's wheel is compo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chakra
Chakras (, ; sa , text=चक्र , translit=cakra , translit-std=IAST , lit=wheel, circle; pi, cakka) are various focal points used in a variety of ancient meditation practices, collectively denominated as Tantra, or the esoteric or inner traditions of Hinduism.Chakra: Religion Encyclopaedia Britannica The concept of the chakra arose in the early traditions of Hinduism. Beliefs differ between the Indian religions, with many Buddhist texts consistently mentioning five chakras, while Hindu sources reference six or seven. Early Sanskrit texts speak of them both as meditative visualizations combining flowers and mantras and as physical entit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Europe
Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russia, which spans roughly 40% of the continent's landmass while accounting for approximately 15% of its total population."The Balkans" , ''Global Perspectives: A Remote Sensing and World Issues Site''. Wheeling Jesuit University/Center for Educational Technologies, 1999–2002. It represents a significant part of Culture of Europe, European culture; the main socio-cultural characteristics of Eastern Europe have historically been defined by the traditions of Slavs and Greeks, as well as by the influence of Eastern Christianity as it developed through t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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