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Cycloidal Gear
The cycloidal gear profile is a form of toothed gear used in mechanical clocks, rather than the involute gear form used for most other gears. The gear tooth profile is based on the epicycloid and hypocycloid curves, which are the curves generated by a circle rolling around the outside and inside of another circle, respectively. When two toothed gears mesh, an imaginary circle, the ''pitch circle'', can be drawn around the centre of either gear through the point where their teeth make contact. The curves of the teeth outside the pitch circle are known as the ''addenda'', and the curves of the tooth spaces inside the pitch circle are known as the ''dedenda''. An addendum of one gear rests inside a dedendum of the other gear. In the cycloidal gears, the addenda of the wheel teeth are convex epi-cycloidal and the dedenda of the pinion are concave hypocycloidal curves generated by the same generating circle. This ensures that the motion of one gear is transferred to the other at l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gérard Desargues
Girard Desargues (; 21 February 1591 – September 1661) was a French mathematician and engineer, who is considered one of the founders of projective geometry. Desargues' theorem, the Desargues graph, and the crater Desargues on the Moon are named in his honour. Born in Lyon, Desargues came from a family devoted to service to the French crown. His father was a royal notary, an investigating commissioner of the Seneschal's court in Lyon (1574), the collector of the tithes on ecclesiastical revenues for the city of Lyon (1583) and for the diocese of Lyon. Girard Desargues worked as an architect from 1645. Prior to that, he had worked as a tutor and may have served as an engineer and technical consultant in the entourage of Richelieu. As an architect, Desargues planned several private and public buildings in Paris and Lyon. As an engineer, he designed a system for raising water that he installed near Paris. It was based on the use of the epicycloidal wheel, the principle of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloidal Drive
A cycloidal drive or cycloidal speed reducer is a mechanism for reducing the speed of an input shaft by a certain ratio. Cycloidal speed reducers are capable of relatively high ratios in compact sizes with very low backlash. The input shaft drives an eccentric bearing that in turn drives the cycloidal disc in an eccentric, cycloidal motion. The perimeter of this disc is geared to a stationary ring gear and has a series of output shaft pins or rollers placed through the face of the disc. These output shaft pins directly drive the output shaft as the cycloidal disc rotates. The radial motion of the disc is not translated to the output shaft. Theory of operation The input shaft is mounted eccentrically to a rolling-element bearing (typically a cylindrical roller bearing), causing the cycloidal disc to wobble in a circle. The cycloidal disc will independently rotate around the bearing as it is pushed against the ring gear. This is similar to planetary gearing. The direction of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Involute
In mathematics, an involute (also known as an evolvent) is a particular type of curve that is dependent on another shape or curve. An involute of a curve is the locus of a point on a piece of taut string as the string is either unwrapped from or wrapped around the curve. It is a class of curves coming under the roulette family of curves. The evolute of an involute is the original curve. The notions of the involute and evolute of a curve were introduced by Christiaan Huygens in his work titled '' Horologium oscillatorium sive de motu pendulorum ad horologia aptato demonstrationes geometricae'' (1673). Involute of a parameterized curve Let \vec c(t),\; t\in _1,t_2 be a regular curve in the plane with its curvature nowhere 0 and a\in (t_1,t_2), then the curve with the parametric representation \vec C_a(t)=\vec c(t) -\frac\; \int_a^t, \vec c'(w), \; dw is an ''involute'' of the given curve. Adding an arbitrary but fixed number l_0 to the integral \Bigl(\int_a^t, \ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloid
In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve. The cycloid, with the cusps pointing upward, is the curve of fastest descent under uniform gravity (the brachistochrone curve). It is also the form of a curve for which the period of an object in simple harmonic motion (rolling up and down repetitively) along the curve does not depend on the object's starting position (the tautochrone curve). History The cycloid has been called "The Helen of Geometers" as it caused frequent quarrels among 17th-century mathematicians. Historians of mathematics have proposed several candidates for the discoverer of the cycloid. Mathematical historian Paul Tannery cited similar work by the Syrian philosopher Iamblichus as evidence that the curve was known in antiquity. English mathematician John Wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Étienne Louis Camus
Charles Étienne Louis Camus (25 August 1699 – 2 February 1768), was a French mathematician and mechanician who was born at Crécy-en-Brie, near Meaux. He studied mathematics, civil and military architecture, and astronomy after leaving Collège de Navarre in Paris. In 1730 he was appointed professor of architecture and, in 1733, associate of the Académie des Sciences. He also became a professor of geometry, secretary to the Academy of Architecture and fellow of the Royal Society of London. In 1727 he presented a memoir to the academy on masting ships, in consequence of which he was named the same year joint mechanician to that body. In 1736 he accompanied Pierre Louis Maupertuis and Alexis Clairaut in the expedition to Lapland for the measurement of a degree of meridian arc. He was the author of a ''Cours de mathématiques'' (Paris, 1766), and a number of essays on mathematical and mechanical subjects. In 1760 he became perpetual secretary of the academy of architecture. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ole Rømer
Ole Christensen Rømer (; 25 September 1644 – 19 September 1710) was a Danish astronomer who, in 1676, made the first measurement of the speed of light. Rømer also invented the modern thermometer showing the temperature between two fixed points, namely the points at which water respectively boils and freezes. In scientific literature, alternative spellings such as "Roemer", "Römer", or "Romer" are common. Biography Rømer was born on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Storm ( – 1690), daughter of a well-to-do alderman. Since 1642, Christen Pedersen had taken to using the name Rømer, which means that he was from the Danish island of Rømø, to distinguish himself from a couple of other people named Christen Pedersen. There are few records of Ole Rømer before 1662, when he graduated from the old Aarhus Katedralskole (the Cathedral school of Aarhus), moved to Copenhagen and matriculated at the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gothic Arch
A pointed arch, ogival arch, or Gothic arch is an arch with a pointed crown, whose two curving sides meet at a relatively sharp angle at the top of the arch. This architectural element was particularly important in Gothic architecture. The earliest use of a pointed arch dates back to bronze-age Nippur. As a structural feature, it was first used in Islamic architecture, but in the 12th century it began to be used in France and England as an important structural element, in combination with other elements, such as the rib vault and later the flying buttress. These allowed the construction of cathedrals, palaces and other buildings with dramatically greater height and larger windows which filled them with light. Early arches Crude arches pointed in shape have been discovered from the Bronze Age site of Nippur dated earlier than 2700 BC. The palace of Nineveh also has pointed arched drains but they have no true keystone. File:Trivikram Temple Ter 1.jpg, Temple of Trivikrama in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear
A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic principle behind the operation of gears is analogous to the basic principle of levers. A gear may also be known informally as a cog. Geared devices can change the speed, torque, and direction of a power source. Gears of different sizes produce a change in torque, creating a mechanical advantage, through their ''gear ratio'', and thus may be considered a simple machine. The rotational speeds, and the torques, of two meshing gears differ in proportion to their diameters. The teeth on the two meshing gears all have the same shape. Two or more meshing gears, working in a sequence, are called a gear train or a '' transmission''. The gears in a transmission are analogous to the wheels in a crossed, belt pulley system. An advantage of gears is tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roots Blower
The Roots-type blower is a positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and carried from the intake side to the exhaust. The most common application of the Roots-type blower has been the induction device on two-stroke diesel engines, such as those produced by Detroit Diesel and Electro-Motive Diesel. Roots-type blowers are also used to supercharge four-stroke Otto cycle engines, with the blower being driven from the engine's crankshaft via a toothed or V-belt, a roller chain or a gear train. The Roots-type blower is named after American inventors and brothers Philander and Francis Marion Roots, founders of the Roots Blower Company of Connersville, Indiana USA, who patented the basic design in 1860 as an air pump for use in blast furnaces and other industrial applications. In 1900, Gottlieb Daimler included a Roots-style blower in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloidal Rotor Construction - 2 Lobes
In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve. The cycloid, with the cusps pointing upward, is the curve of fastest descent under uniform gravity (the brachistochrone curve). It is also the form of a curve for which the period of an object in simple harmonic motion (rolling up and down repetitively) along the curve does not depend on the object's starting position (the tautochrone curve). History The cycloid has been called "The Helen of Geometers" as it caused frequent quarrels among 17th-century mathematicians. Historians of mathematics have proposed several candidates for the discoverer of the cycloid. Mathematical historian Paul Tannery cited similar work by the Syrian philosopher Iamblichus as evidence that the curve was known in antiquity. English mathematician John Wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
