"a place to stand, and I shall move the Earth with it' is a remark of Archimedes who formally stated the correct mathematical principle of levers (quoted by Pappus of Alexandria). It is assumed that in ancient Egypt, constructors used the lever to move and uplift obelisks weighing more than 100 tons. A lever is a beam connected to ground by a hinge, or pivot, called a fulcrum. The ideal lever does not dissipate or store energy, which means there is no friction in the hinge or bending in the beam. In this case, the power into the lever equals"
"of the lever are found in the Peripatetic school of the followers of Aristotle, and are sometimes attributed to Archytas. According to Pappus of Alexandria, Archimedes' work on levers caused him to remark: ""Give me a place to stand on, and I will move the Earth."" () Plutarch describes how Archimedes designed block-and-tackle pulley systems, allowing sailors to use the principle of leverage to lift objects that would otherwise have been too heavy to move. Archimedes has also been credited with improving the power and accuracy of the catapult, and with inventing the odometer during the First Punic War. The"
"Simpson Chain The Simpson Chain or Simpson Lever Chain was an English-made bicycle chain invented by William Spears Simpson in 1895. The design departed from the standard roller bicycle chain: it was composed of linked triangles forming two levels. The inner level was driven by the chainring and the outer drove the rear cog. Instead of teeth, the chainring and cog had grooves into which the rollers of the chain engaged. Simpson made claims, widely discredited, that the levers of this chain provided a mechanical advantage that could amplify energy produced by the cyclist. Simpson hired top cyclists such as"
"turn, revolved around the Sun. Though the arguments he used were lost, Plutarch stated that Seleucus was the first to prove the heliocentric system through reasoning. In the 3rd century BCE, the Greek mathematician Archimedes of Syracuse ( (287–212 BCE) – generally considered to be the greatest mathematician of antiquity and one of the greatest of all time – laid the foundations of hydrostatics, statics and calculated the underlying mathematics of the lever. A leading scientist of classical antiquity, Archimedes also developed elaborate systems of pulleys to move large objects with a minimum of effort. The Archimedes' screw underpins modern"
"elements, calling them ""simple machines"". Modern machine theory analyzes machines as kinematic chains composed of elementary linkages called kinematic pairs. The idea of a simple machine originated with the Greek philosopher Archimedes around the 3rd century BC, who studied the Archimedean simple machines: lever, pulley, and screw. He discovered the principle of mechanical advantage in the lever. Archimedes' famous remark with regard to the lever: ""Give me a place to stand on, and I will move the Earth."" () expresses his realization that there was no limit to the amount of force amplification that could be achieved by using mechanical"
"the lever, which was first demonstrated by Archimedes, and of the center of mass (or centroid), which he had found for many special shapes. Archimedes did not admit the method of indivisibles as part of rigorous mathematics, and therefore did not publish his method in the formal treatises that contain the results. In these treatises, he proves the same theorems by exhaustion, finding rigorous upper and lower bounds which both converge to the answer required. Nevertheless, the mechanical method was what he used to discover the relations for which he later gave rigorous proofs. To explain Archimedes' method today, it"
"by doubling their productivity, and now the spinning jenny could supply that demand by increasing the spinners' productivity even more. The machine produced coarse thread. The idea was developed by Hargreaves as a metal frame with eight wooden spindles at one end. A set of eight rovings was attached to a beam on that frame. The rovings when extended passed through two horizontal bars of wood that could be clasped together. These bars could be drawn along the top of the frame by the spinner's left hand thus extending the thread. The spinner used his right hand to rapidly turn"
"in the world, the Bagger 288, is propelled by continuous tracks. Propellers (as well as screws, fans and rotors) are used to move through a fluid. Propellers have been used as toys since ancient times, however it was Leonardo da Vinci who devised what was one of the earliest propeller driven vehicles, the ""aerial-screw"". In 1661, Toogood & Hays adopted the screw for use as a ship propeller. Since then, the propeller has been tested on many terrestrial vehicles, including the Schienenzeppelin train and numerous cars. In modern times, propellers are most prevalent on watercraft and aircraft, as well as"
"push of a lever. A draw strap connected to the waist and arms enables the person to walk. When the person walks, he or she swings the arms. Strings are attached to the hands, so when the arms swing back and forth, the motion creates tension, which moves the legs forward and so on."" Tibay's more recent project is a perforated wall to run along the whole eastern coast of the Philippines called ""Typhoon Breaker."" Eulogio Tibay Eulogio Camacho Tibay is a Filipino inventor. He invented a special screw which can withstand all kinds of motion and vibration, a corrugated"
"arc through more than 360° by attaching the blade to a rotating shaft. Propellers can have a single blade, but in practice there are nearly always more than one so as to balance the forces involved. The origin of the screw propeller starts with Archimedes, who used a screw to lift water for irrigation and bailing boats, so famously that it became known as Archimedes' screw. It was probably an application of spiral movement in space (spirals were a special study of Archimedes) to a hollow segmented water-wheel used for irrigation by Egyptians for centuries. Leonardo da Vinci adopted the"
"set of levers to prevent the bolt from moving in the lock, was perfected by Robert Barron in 1778. His double acting lever lock required the lever to be lifted to a certain height by having a slot cut in the lever, so lifting the lever too far was as bad as not lifting the lever far enough. This type of lock is still currently used today. The lever tumbler lock was greatly improved by Jeremiah Chubb in 1818. A burglary in Portsmouth Dockyard prompted the British Government to announce a competition to produce a lock that could be opened"
"Haltaus suggested that a lever through the prow mast would have allowed the crew to turn the ""corvus"" by turning the mast. A pulley was placed on the top of a 24-foot mast that raised the bridge in order to use the device. German classical scholar Wilhelm Ihne proposed another version of ""corvus"" that resembled Freinsheim’s crane with adjustments in the lengths of the sections of the bridge. His design placed the ""corvus"" twelve feet above the deck and had the ""corvus"" extend out from the mast a full 36 feet with the base of the near end connected to"
"""a poor fellow afflicted with myasthenia gravis ... [who] devised complicated lever arrangements to enable him to use what little strength he had."" Remote manipulator A remote manipulator, also known as a telefactor, telemanipulator, or waldo (after the short story ""Waldo"" by Robert A. Heinlein which features a man who invents and uses such devices), is a device which, through electronic, hydraulic, or mechanical linkages, allows a hand-like mechanism to be controlled by a human operator. The purpose of such a device is usually to move or manipulate hazardous materials for reasons of safety, similar to the operation and play"
"""contrivance"" was named after Charles Spackman Barker (1804-79), engineer and organ-builder. A similar lever was developed by David Hamilton in 1835, and there has been debate whether Barker stole the design. Barker lever The Barker lever is a pneumatic system which multiplies the force of a finger on the key of a tracker pipe organ. It employs the wind pressure of the organ to inflate small bellows called ""pneumatics"" to overcome the resistance of the pallets (valves) in the organ's wind-chest . This lever allowed for the development of larger, more powerful organs still responsive to the human hand. These"
"locks were invented in 1778 by Robert Barron of England. These required the lever to be lifted to a certain height by having a slot cut in the lever, so lifting the lever too far was as bad as not lifting the lever far enough. This type of lock is still used today, on doors in Europe, Africa, South America and some other parts of the world. The lock is made up of levers (usually made out of non-ferrous metals). Each lever needs to be lifted to a specific height by the key in order for the locking bolt to"
"Archimedean simple machines: lever, pulley, and screw. Archimedes discovered the principle of mechanical advantage in the lever. Later Greek philosophers defined the classic five simple machines (excluding the inclined plane) and were able to roughly calculate their mechanical advantage. Heron of Alexandria (ca. 10–75 AD) in his work ""Mechanics"" lists five mechanisms that can ""set a load in motion""; lever, windlass, pulley, wedge, and screw, and describes their fabrication and uses. However, the Greeks' understanding was limited to statics (the balance of forces) and did not include dynamics (the tradeoff between force and distance) or the concept of work. During"
"of timber and for access to retrieve the bound rafts. Further, it allowed Calvin to operate within the British (commonwealth) system which enabled shipping to Great Britain. Vertically integrated, Calvin arranged shipment via company offices in Liverpool and Glasgow. The rafts were fastened together into units called ""drams"" that could be as large as one-half mile in length. In the early timber days, the rafts were powered either by sail or by the men using long oars known as ""sweeps"". The men, usually French-Canadians, would guide the rafts through the currents of the St. Lawrence to Quebec, a trip that"
"lever fully forward, the grip is open, and the cable is free to fall out (necessary when the cable crosses under another line, as well as at the ends of lines, and at ""let-go"" curves). With the cable lifted into the jaws, the operating lever is pulled back, forcing the jaws between two fixed rollers, and capturing the cable between the grip's replaceable mild-steel dies (but without applying pressure). To start moving the car, the operating lever is pulled back further, squeezing the cable between the dies. The grip was designed by the German railway mechanical engineer William Eppelsheimer in"
"At the point of giving up, he asked his wife for ideas. She answered: ""You always need a screwdriver for something."" Rybczynski discovered that the screwdriver is a relatively new addition to the toolbox, an invention of the Late Middle Ages in Europe and the only major mechanical device not independently invented by the Chinese. Leonardo da Vinci was there at the start, designing a number of screw-cutting machines with interchangeable gears. Nevertheless, it took generations for the screw (and with it, the screwdriver and lathe) to come into general use, and it was not until modern times that improvements"
"Beugniot lever The Beugniot lever (""Beugniot-Hebel"") is a mechanical device used on a number of locomotives to improve curve running. It was named after its inventor Édouard Beugniot. Around 1860, when Beugniot was the chief engineer at the firm of Köchlin, he developed a system whereby wheelsets are housed in pairs in the locomotive frame, with side-play, and connected by a lever. These levers are fixed to the frame in the centre and thus enable the sideways movement of the connected axles in opposite directions. In this way, instead of being fixed in the frame, the axles are able to"
"safely be moved a short distance using the lever as a fulcrum linked to the piston inside. Although the linkage was designed to give leverage, the Johnson Bar would take a firm throw to move and lock in position. Some locomotives had a screw reversing gear instead. The other use of the lever is to set the point of steam cut-off. This is measured as the percentage of the piston stroke during which live boiler steam is still being admitted to the cylinder. For starting the locomotive (when maximum torque is required), ""full"" cut-off may be as high as 85%,"
"link length and mass, and in 1788 the French chemist Antoine Lavoisier commissioned a set of nine brass cylinders—a [French] pound and decimal subdivisions thereof for his experimental work. In 1790, a proposal floated by the French to Britain and the United States, to establish a uniform measure of length, a ""metre"" based on the period of a pendulum with a beat of one second, was defeated in the British Parliament and United States Congress. The underlying issue was failure to agree on the latitude for the definition, since gravitational acceleration and therefore the length of the pendulum, is proportional"
"they were able to erect one successfully. First Hopkins and Rais Abdel Aleem organized an experiment to tow a block of stone weighing about 25 tons. They prepared a path by embedding wooden rails into the ground and placing a sledge on them bearing a megalith weighing about 25 tons. Initially they used more than 100 people to try to tow it but were unable to budge it. Finally, with well over 130 people pulling at once and an additional dozen using levers to prod the sledge forward, they moved it. Over the course of a day, the workers towed"
"Differential pulley A differential pulley, also called ""Weston differential pulley"", sometimes ""chain hoist"" or colloquially ""chain fall"", is used to manually lift very heavy objects like car engines. It is operated by pulling upon the slack section of a continuous chain that wraps around pulleys. The relative size of two connected pulleys determines the maximum weight that can be lifted by hand. The load will remain in place (and not lower under the force of gravity) until the chain is pulled. The differential pulley was invented in 1854 by Thomas Aldridge Weston from King's Norton, England. The pulleys were manufactured"
"weight-driven movements. In the mid-16th century, Christiaan Huygens took an idea from Galileo Galilei and developed it into the first modern pendulum mechanism. However, whereas the spring or the weight provided the motive power, the pendulum merely controlled the rate of release of that power via some escape mechanism (an escapement) at a regulated rate. The Smithsonian Institution has in its collection a clockwork monk, about high, possibly dating as early as 1560. The monk is driven by a key-wound spring and walks the path of a square, striking his chest with his right arm, while raising and lowering a"
"base metals like lead, into gold. It was the Swiss alchemist and surgeon Paracelsus who first challenged the Ancient Greek idea of four elements. In 1526 Paracelsus was in Basel, when the famous printer Frobenius was told he would have to have his leg amputated in a life-saving operation. Instead of accepting the received wisdom, he called upon Paracelsus who cured him in the unconventional way of using his alchemical knowledge. This established him as a radical thinker, giving weight to his ideas, principal amongst which was the idea that the world was actually made of three elements: the tria"
"shape. This means that more power is lost when going uphill. With a bike fitted with a 5 -bar linkage, the wheel moves in such a large arc that it is moving almost vertically. This way the power loss is reduced by up to 30%. Archimedes applied geometry to the study of the lever. Into the 1500s the work of Archimedes and Hero of Alexandria were the primary sources of machine theory. It was Leonardo da Vinci who brought an inventive energy to machines and mechanism. In the mid-1700s the steam engine was of growing importance, and James Watt realized"
"Several experiments were carried out, including a large scale test with 500 schoolchildren aiming mirrors at a of a Roman sailing ship 400 feet (120 m) away. In all of the experiments, the sail failed to reach the 210 °C (410 °F) required to catch fire, and the verdict was again ""busted"". The show concluded that a more likely effect of the mirrors would have been blinding, dazzling, or distracting the crew of the ship. While Archimedes did not invent the lever, he gave an explanation of the principle involved in his work ""On the Equilibrium of Planes"". Earlier descriptions"
"of stone and move them with the aid of the Earth's magnetic energy. Other currently available explanations center on Leedskalnin's stonemasonry and logging experiences that presumably allowed him to apply his work skills creatively to a tedious process of moving large blocks of stone using levers, wheels, axles, pulleys, ramps, and wedges without any power equipment. The emotional side of Ed Leedskalnin's life story drew the attention of songwriters and performers, including: Edward Leedskalnin Edward Leedskalnin (modern ) (January 12, 1887 – December 7, 1951) was a Latvian emigrant to the United States, self-taught engineer and sculptor who single-handedly built"
"in London and received a medal for ""original application, practical utility and success"". An ironmonger challenged the Tangyes that the pulley had been in use for 30 years before Weston's patent but the judge, William Page Wood ruled in favour of the Tangyes because the engaging mechanism was substantially different from the one presented as evidence. The Yale Lock Company acquired the patent rights in 1876. A dumb pulley can lift very large masses a short distance. It consists of two fixed pulleys of unequal radii that are attached to each other and rotate together, a single pulley bearing the"
"open. The lock was at the limits of the precision manufacturing capabilities of the time and was said by its inventor to be unpickable. In the same year Bramah started the Bramah Locks company at 124 Piccadilly, and displayed the ""Challenge Lock"" in the window of his shop from 1790, challenging ""...the artist who can make an instrument that will pick or open this lock"" for the reward of £200. The challenge stood for over 67 years until, at the Great Exhibition of 1851, the American locksmith Alfred Charles Hobbs was able to open the lock and, following some argument"
"angle lever paradox"", first discussed by Gilbert Newton Lewis and Richard Chase Tolman in 1909. Suppose a right-angle lever with endpoints ""abc"". In its rest frame, the forces formula_5 towards ""ba"" and formula_6 towards ""bc"" must be equal to obtain equilibrium, thus no torque is given by the law of the lever: where formula_2 is the torque, and formula_9 the rest length of one lever arm. However, due to length contraction, ""ba"" is longer than ""bc"" in a non-co-moving system, thus the law of the lever gives: It can be seen that the torque is not zero, which apparently would"
"the world without the use of his hands, which are so admirably adapted to the act of obedience of his will"". Darwin (1871:52) and many models on bipedal origins are based on this line of thought. Gordon Hewes (1961) suggested that the carrying of meat ""over considerable distances"" (Hewes 1961:689) was the key factor. Isaac (1978) and Sinclair et al. (1986) offered modifications of this idea, as indeed did Lovejoy (1981) with his ""provisioning model"" described above. Others, such as Nancy Tanner (1981), have suggested that infant carrying was key, while others again have suggested stone tools and weapons drove"