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Trebuchet
A trebuchet (french: trébuchet) is a type of catapult that uses a long arm to throw a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than that of a traditional catapult. There are two main types of trebuchet. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. It first appeared in China in the 4th century BC. Carried westward by the Avars, the technology was adopted by the Byzantines in the late 6th century AD and by their neighbors in the following centuries. The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century. Etymology and terminology It is uncer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trebuchet Castelnaud
A trebuchet (french: trébuchet) is a type of catapult that uses a long arm to throw a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than that of a traditional catapult. There are two main types of trebuchet. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. It first appeared in China in the 4th century BC. Carried westward by the Avars, the technology was adopted by the Byzantines in the late 6th century AD and by their neighbors in the following centuries. The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century. Etymology and terminology It is uncer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trebuchet2
A trebuchet (french: trébuchet) is a type of catapult that uses a long arm to throw a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than that of a traditional catapult. There are two main types of trebuchet. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. It first appeared in China in the 4th century BC. Carried westward by the Avars, the technology was adopted by the Byzantines in the late 6th century AD and by their neighbors in the following centuries. The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century. Etymology and terminology It is uncert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mangonel
The mangonel, also called the traction trebuchet, was a type of trebuchet used in Ancient China starting from the Warring States period, and later across Eurasia by the 6th century AD. Unlike the later counterweight trebuchet, the mangonel operated on manpower pulling cords attached to a lever and sling to launch projectiles. Although the mangonel required more men to function, it was also less complex and faster to reload than the torsion-powered onager which it replaced in early Medieval Europe. It was replaced as the primary siege weapon in the 12th and 13th centuries by the counterweight trebuchet. A common misconception about the mangonel is that it was a torsion siege engine. Etymology ''Mangonel'' is probably derived from the Greek ''mangana'', "a generic term for construction machinery." It could also be derived from ''mangon'', a French hard stone found in the south of France. In Latin it is called a ''manganum'', in French a ''manganeau'', and in English a ''ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catapult
A catapult is a ballistic device used to launch a projectile a great distance without the aid of gunpowder or other propellants – particularly various types of ancient and medieval siege engines. A catapult uses the sudden release of stored potential energy to propel its payload. Most convert tension or torsion energy that was more slowly and manually built up within the device before release, via springs, bows, twisted rope, elastic, or any of numerous other materials and mechanisms. In use since ancient times, the catapult has proven to be one of the most persistently effective mechanisms in warfare. In modern times the term can apply to devices ranging from a simple hand-held implement (also called a "slingshot") to a mechanism for launching aircraft from a ship. The earliest catapults date to at least the 7th century BC, with King Uzziah, of Judah, recorded as equipping the walls of Jerusalem with machines that shot "great stones". Catapults are mentioned in Yaju ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sling (weapon)
A sling is a projectile weapon typically used to throw a blunt projectile such as a stone, clay, or lead " sling-bullet". It is also known as the shepherd's sling or slingshot (in British English). Someone who specializes in using slings is called a slinger. A sling has a small cradle or ''pouch'' in the middle of two retention cords. A projectile is placed in the pouch. There is a loop on the end of one side of the retention cords. Depending on the design of the sling, either the middle finger or the wrist is placed through a loop on the end of one cord, and a tab at the end of the other cord is placed between the thumb and forefinger. The sling is swung in an arc, and the tab released at a precise moment. This action releases the projectile to fly to the target. The sling is much more than merely an extension of a human arm. By its double-pendulum kinetics, the sling enables stones (or spears) to be thrown much further than they could be by hand alone. The sling is i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counterweight
A counterweight is a weight that, by applying an opposite force, provides balance and stability of a mechanical system. The purpose of a counterweight is to make lifting the load faster and more efficient, which saves energy and causes less wear and tear on the lifting machine. Counterweights are often used in traction lifts (elevators), cranes and fun fair rides. In these applications, the expected load multiplied by the distance that load will be spaced from the central support (called the "tipping point") must be equal to the counterweight's mass times its distance from the tipping point in order to prevent over-balancing either side. This distance times mass is called the load moment. A counterbalance is a weight or force that balances or offsets another as when two objects of equal weight, power, or influence are acting in opposition to each other. The objects are then said to be in counterbalance. Counterweights in action Trebuchet: There are five major components of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potential Energy
In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potential energy of an object, the elastic potential energy of an extended spring, and the electric potential energy of an electric charge in an electric field. The unit for energy in the International System of Units (SI) is the joule, which has the symbol J. The term ''potential energy'' was introduced by the 19th-century Scottish engineer and physicist William Rankine, although it has links to Greek philosopher Aristotle's concept of potentiality. Potential energy is associated with forces that act on a body in a way that the total work done by these forces on the body depends only on the initial and final positions of the body in space. These forces, that are called ''conservative forces'', can be represented at every point in space by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treadwheel
A treadwheel, or treadmill, is a form of engine typically powered by humans. It may resemble a water wheel in appearance, and can be worked either by a human treading paddles set into its circumference (treadmill), or by a human or animal standing inside it (treadwheel). These devices are no longer used for power or punishment, and the term " treadmill" has come to mean an exercise machine for running or walking in place. History Uses of treadwheels included raising water, to power cranes, or grind grain. They were used extensively in the Greek and Roman world, such as in the reverse overshot water-wheel used for dewatering purposes. They were widely used in the Middle ages to lift the stones in the construction of Gothic cathedrals. There is a literary reference to one in 1225, and one treadwheel crane survives at Chesterfield, Derbyshire and is housed in the Museum. It has been dated to the early 14th century and was housed in the top of the church tower until its removal in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winch
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attached to a hand crank. Traditionally, winches on ships accumulated wire or rope on the drum; those that do not accumulate, and instead pass on the wire/rope (see yacht photo above), are called capstans. Despite this, sailboat capstans are most often referred to as winches. Winches are the basis of such machines as tow trucks, steam shovels and elevators. More complex designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. It might include a solenoid brake and/or a mechanical brake or ratchet and pawl which prevents it unwinding unless the pawl is retracted. The rope may be stored on the winch. When trimming a line on a sailboat, the crew member turns the winch handle with one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block And Tackle
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads. The pulleys are assembled to form blocks and then blocks are paired so that one is fixed and one moves with the load. The rope is threaded through the pulleys to provide mechanical advantage that amplifies the force applied to the rope. Hero of Alexandria described cranes formed from assemblies of pulleys in the first century. Illustrated versions of Hero's ''Mechanica'' (a book on raising heavy weights) show early block and tackle systems. Overview A block is a set of pulleys or sheaves mounted on a single frame. An assembly of blocks with a rope threaded through the pulleys is called tackle. The process of threading ropes or cables through blocks is called "reeving", and a threaded block and tackle is said to have been "rove". A block and tackle system amplifies the tension force in the rope to lift heavy loads. They are comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Power
Human power is work or energy that is produced from the human body. It can also refer to the power (rate of work per time) of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or other humans. World records of power performance by humans are of interest to work planners and work-process engineers. The average level of human power that can be maintained over a certain duration of time is interesting to engineers designing work operations in industry. Human-powered transport includes bicycles, rowing, skiing and many other forms of mobility. Human-powered equipment is occasionally used to generate, and sometimes to store, electrical energy for use where no other source of power is available. These include the Gibson girl survival radio, wind-up or (clockwork) radio and pedal radio. Available power Normal human metabolism produces heat at a basal metabolic rate of around 80 watts. During a bicycle race, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
