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Fusee (horology)
Used in antique spring-powered mechanical watches and clocks, a fusee (from the French ''fusée'', wire wound around a spindle) is a cone-shaped pulley with a helical groove around it, wound with a cord or chain which is attached to the mainspring barrel. Fusees were used from the 15th century to the early 20th century to improve timekeeping by equalizing the uneven pull of the mainspring as it ran down. Gawaine Baillie stated of the fusee, "Perhaps no problem in mechanics has ever been solved so simply and so perfectly." History The origin of the fusee is not known. Many sources erroneously credit clockmaker Jacob Zech of Prague with inventing it around 1525. The earliest definitely dated fusee clock was made by Zech in 1525, but the fusee actually appeared earlier, with the first spring driven clocks in the 15th century., p.127-128, p.121 The idea probably did not originate with clockmakers, since the earliest known example is in a crossbow windlass shown in a 1405 mili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (device)
A spring is an elastic object that stores mechanical energy. In everyday use the term often refers to coil springs, but there are many different spring designs. Modern springs are typically manufactured from spring steel, although some non-metallic objects like the bow are also springs. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The ''rate'' or ''spring constant'' of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve. An extension or compression spring's rate is expressed in units of force divided by distance, for example or N/m or lbf/in. A torsion spring is a spring that works by twisting; when it is twisted about its axis by an angle, it produces a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (device)
A spring is an elastic object that stores mechanical energy. In everyday use the term often refers to coil springs, but there are many different spring designs. Modern springs are typically manufactured from spring steel, although some non-metallic objects like the bow are also springs. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The ''rate'' or ''spring constant'' of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve. An extension or compression spring's rate is expressed in units of force divided by distance, for example or N/m or lbf/in. A torsion spring is a spring that works by twisting; when it is twisted about its axis by an angle, it produces a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheel Train (horology)
In horology, a wheel train (or just train) is the gear train of a mechanical watch or clock. Although the term is used for other types of gear trains, the long history of mechanical timepieces has created a traditional terminology for their gear trains which is not used in other applications of gears. Watch movements are very standardized, and the wheel trains of most watches have the same parts. The wheel trains of clocks are a little more varied, with different numbers of wheels depending on the type of clock and how many hours the clock runs between windings (the "going"). However, the wheel trains of clocks and watches share the same terminology, and are similar enough that they can be described together. The large gears in timepieces are generally called ''wheels'', the smaller gears they mesh with (large to small, large to small) are called pinions, and the shafts that the wheels and pinions are mounted on are called ''arbors''. The wheels are mounted between the plates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbor (tool)
A mandrel, mandril, or arbor is a gently tapered cylinder against which material can be forged or shaped (e.g., a ring mandrel - also called a triblet - used by jewelers to increase the diameter of a wedding ring), or a flanged or tapered or threaded bar that grips a workpiece to be machined in a lathe. A flanged mandrel is a parallel bar of a specific diameter with an integral flange towards one end, and threaded at the opposite end. Work is gripped between the flange and a nut on the thread. A tapered mandrel (often called a plain mandrel) has a taper of approximately 0.005 inches per foot and is designed to hold work by being driven into an accurate hole on the work, gripping the work by friction. A threaded mandrel may have a male or female thread, and work which has an identical thread is screwed onto the mandrel. On a lathe, mandrels are commonly mounted between centres and driven by a lathe dog (typically the flanged or tapered mandrels), but may also be gripped in a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusee
Fusee or fusée may refer to: * Fusee (horology), a component of a clock * Flare, a pyrotechnic device sometimes called a Fusee * Fusee, an old word for "flintlock Flintlock is a general term for any firearm that uses a flint-striking lock (firearm), ignition mechanism, the first of which appeared in Western Europe in the early 16th century. The term may also apply to a particular form of the mechanism its ..., rifle, particularly a light musket" See also * Fuser (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Chronometer
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT), or in the modern world its successor Coordinated Universal Time (UTC), and the time at the current location found from observations of celestial bodies. When first developed in the 18th century, it was a major technical achievement, as accurate knowledge of the time over a long sea voyage was vital for effective navigation, lacking electronic or communications aids. The first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent experimentation and testing that revolutionized naval (and later aerial) navigation and enabling the Age of Discovery and Colonialism to accelerate. The term ''chronometer'' was coined from the Greek words '' χρόνος (chronos)'' (meaning time) and ''meter'' (meaning measure) in 1713 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maintaining Power
In horology, a maintaining power is a mechanism for keeping a clock or watch going while it is being wound. Huygens The weight drive used by Christiaan Huygens in his early clocks acts as a maintaining power. In this layout, the weight which drives the clock is carried on a pulley and the cord (or chain) supporting the weight is wrapped around the main driving wheel on one side and the rewinding wheel on the other. The chain then loops down from the rewinding wheel and up again to the main driving wheel via a second pulley carrying a small tensioning weight which ensures the loop stays taut and the chain engages well with the main driving wheel and rewinding wheel. In the first illustration the clock is fully wound, the driving weight is up and the tensioning weight down, a ratchet on the winding wheel prevents it from turning back. The driving weight pulls the main wheel in the direction of the arrow. In the second illustration the driving weight has reached its lowest point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Harrison
John Harrison ( – 24 March 1776) was a self-educated English Carpentry, carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the History of longitude, problem of calculating longitude while at sea. Harrison's solution revolutionized navigation and greatly increased the safety of long-distance sea travel. The problem he solved was considered so important following the Scilly naval disaster of 1707 that the Parliament of Great Britain, British Parliament offered financial rewards of up to £20,000 (equivalent to £ in ) under the 1714 Longitude Act. In 1730, Harrison presented his first design, and worked over many years on improved designs, making several advances in time-keeping technology, finally turning to what were called sea watches. Harrison gained support from the Board of Longitude, Longitude Board in building and testing his designs. Toward the end of his life, he received recognition and a reward from Parliament. Harri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catgut
Catgut (also known as gut) is a type of cord that is prepared from the natural fiber found in the walls of animal Gut (anatomy), intestines. Catgut makers usually use sheep or goat intestines, but occasionally use the intestines of cattle, Domestic pig, hogs, horses, mules, or donkeys. Despite the name, catgut is not made from cat intestines. Etymology The word ''catgut'' may have been an abbreviation of the word "cattlegut". Alternatively, it may derive by folk etymology from ''kitgut'' or ''kitstring'' — the dialectal word ''kit'', meaning fiddle, having at some point been confused with the word ''kit'' for a young cat, the word "kit" being possibly derived from Welsh language, Welsh. Common uses Stringed instruments For a long time, catgut was the most common material for the strings (music), strings of harps, lutes, violins, violas, cellos, and double basses, acoustic guitars and other String instrument, stringed musical instruments, as well as older marching snare drums. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watch
A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain. Watches were developed in the 17th century from spring-powered clocks, which appeared as early as the 14th century. During most of its history the watch was a mechanical device, driven by clockwork, powered by winding a mainspring, and keeping time with an oscillating balance wheel. These are called ''mechanical watches''. In the 1960s the electronic ''quartz watch'' was invented, which was powered by a battery and kept time with a vibrating quartz crystal. By the 1980s the quartz watch had taken over most of the market from the mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperboloid
In geometry, a hyperboloid of revolution, sometimes called a circular hyperboloid, is the surface generated by rotating a hyperbola around one of its principal axes. A hyperboloid is the surface obtained from a hyperboloid of revolution by deforming it by means of directional scalings, or more generally, of an affine transformation. A hyperboloid is a quadric surface, that is, a surface defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, a hyperboloid is characterized by not being a cone or a cylinder, having a center of symmetry, and intersecting many planes into hyperbolas. A hyperboloid has three pairwise perpendicular axes of symmetry, and three pairwise perpendicular planes of symmetry. Given a hyperboloid, one can choose a Cartesian coordinate system such that the hyperboloid is defined by one of the following equations: : + - = 1, or : + - = -1. The coordinate axes are axes of symmetry of the hyperboloid and the ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Advantage
Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for this is the ''law of the lever.'' Machine components designed to manage forces and movement in this way are called mechanisms. An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal machine does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take into account departures from the ideal. Lever The lever is a movable bar that pivots on a fulcrum attached to or positioned on or across a fixed point. The lever operates by applying forces at different distances from the fulcrum, or pivot. The location of the fulcrum determines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
