58 Fun Facts About Mechanical

How many classical simple machines were defined by Renaissance scientists?

Six: lever, wheel and axle, pulley, inclined plane, wedge and screw make up the classical list, and all multiply force by trading it against distance.

What is the fixed pivot point of a lever called?

Levers come in three classes depending on where fulcrum, load and effort sit.

The word 'lever' ultimately comes from a Latin adjective meaning what?

Light: 'lever' comes from Latin levare, 'to raise', built on the adjective levis, 'light', which also gave English 'levity' and 'alleviate'.

The earliest evidence of pulleys comes from Mesopotamia and which other civilisation, around 1900 BC?

Egypt: pulley evidence dates to the Twelfth Dynasty (about 1991-1802 BC), alongside Mesopotamia's early second millennium BC; the Greek Archytas of Tarentum described the device much later.

A screw converts rotation into what kind of movement?

Linear: turning a screw advances it along its axis by one thread pitch per revolution, and the smaller the pitch, the greater the mechanical advantage.

Thomas Newcomen's atmospheric engine of 1712 was mainly used to do what?

Pumping water out of mines: the first Newcomen engine, at a Dudley Castle colliery in 1712, condensed steam to make a partial vacuum so atmospheric pressure did the work of each pump stroke.

James Watt's improved steam engine roughly did what to the Newcomen engine's fuel efficiency?

Doubled it: the separate condenser kept the cylinder hot, and Watt's engines of the late 1770s did roughly twice the work per bushel of coal of the best Newcomen engines of the day.

James Watt adopted the term 'horsepower' to compare his engines with what?

Draft horses: Watt timed a brewery's mill horse in 1782 and, with Matthew Boulton, settled on a standard figure the next year so buyers could compare engines with the horses they replaced.

One imperial horsepower was standardised by Watt and Boulton as how many foot-pounds per minute?

33,000 foot-pounds per minute: the rounded constant 5,252 in the torque-horsepower formula is simply 33,000 divided by 2π.

Who first invented the centrifugal 'fly-ball' governor Watt added to engines in 1788?

Christiaan Huygens devised the centrifugal governor in the 17th century to regulate the gap between millstones in windmills; Watt adapted it to throttle steam engines in 1788.

What are the four strokes of a four-stroke engine, in order?

Intake, compression, power, exhaust: the cylinder draws in its charge, squeezes it, burns it to drive the power stroke, then expels the gases, taking two crankshaft revolutions per cycle.

Which German engineer designed the first modern internal combustion engine, in 1876?

Nicolaus Otto built the first compressed-charge four-stroke engine in 1876, and German engineering standards define an 'Ottomotor' as any engine ignited by a timed spark.

What ignites the fuel in a diesel engine?

The heat of compressed air: a diesel squeezes its charge to roughly a fifteenth to a twentieth of its volume, heating it past the fuel's ignition point, which is why it is called a compression-ignition engine.

At the 1900 World's Fair, a Diesel engine was famously demonstrated running on which fuel?

Peanut oil: at the 1900 World's Fair a small Diesel engine was shown running on peanut oil at the request of the host government, an idea Diesel himself later championed; modern biodiesel revisits it.

Rudolf Diesel was born in 1858 in which city?

Paris: Diesel was born there on 18 March 1858 to Bavarian immigrants who ran a leather-goods business; the family was expelled to London in 1870 when the Franco-Prussian War began.

A flywheel is a store of which kind of energy?

Rotational kinetic energy: the stored energy grows with the square of the spin rate, so carbon-fibre flywheels built to run at tens of thousands of rpm store far more than heavy steel ones.

In a car, what does the differential allow the two wheels on a drive axle to do?

Turn at different speeds when cornering: the outer wheel travels farther than the inner, and the differential's gears let the two half-shafts spin at speeds whose average is the input speed.

What does a crankshaft convert?

Reciprocating motion into rotation: connecting rods push on the offset crankpins, turning the up-and-down strokes in the cylinders into the crankshaft's spin.

In a piston engine, what does the camshaft operate?

Its pointed cams turn rotation back into the up-and-down motion the valves need.

Which Greek letter usually represents torque in physics?

Tau (τ) is the usual symbol for torque, defined as the cross product of lever arm and force; engineers often say 'moment' where physicists say torque.

Who invented the modern steam turbine in 1884?

Charles Parsons patented his reaction steam turbine in 1884; his Turbinia of 1894 was the first turbine-powered steamship and gate-crashed the Royal Navy's 1897 Spithead review.

Which thermodynamic cycle describes an air-breathing jet engine?

Brayton: the cycle compresses air, heats it at constant pressure in the combustor and expands it through a turbine that drives the compressor, with the leftover energy leaving as thrust.

Which English RAF officer co-created the turbojet, first run as a prototype in 1937?

Frank Whittle's Power Jets WU first ran on 12 April 1937; Germany's Hans von Ohain, working independently, built the engine that powered the first jet flight in 1939.

The rotor of a Wankel engine is roughly the shape of what?

A Reuleaux triangle: the three-sided rotor with bulged faces spins inside an epitrochoid-shaped housing, giving three power pulses per rotor revolution.

The hydraulic press patented in 1795 is also known by which inventor's name?

Joseph Bramah patented the hydraulic press in 1795, hence 'Bramah press'; the Yorkshire-born locksmith also patented an improved flush toilet in 1778 and the famous Bramah lock.

The hydraulic press works on a pressure principle named after which scientist?

Pascal's principle: pressure applied to a confined fluid is transmitted undiminished throughout it, so a small force on a small plunger produces a much larger force on a large one.

What was Archimedes' screw used for in antiquity?

Lift water for irrigation: a helix turning inside a tilted tube raises water, and the device irrigated fields and drained mines and ships' bilges in antiquity; run in reverse, modern versions generate power.

The Antikythera mechanism was recovered from a shipwreck in which year?

1901: sponge divers working the wreck off Antikythera brought up the corroded bronze device, whose surviving fragments hold at least 30 meshing gears that tracked the Moon and predicted eclipses.

What component distinguishes a Stirling engine from other closed-cycle hot-air engines?

A regenerator: Robert Stirling, a Scottish clergyman, patented his 'economiser' in 1816, a heat store between the hot and cold spaces that gives the engine its efficiency.

Hooke's law states that the force needed to stretch a spring scales how with the distance?

Linearly: F = kx, so doubling the extension doubles the force; the hairspring of a watch's balance wheel relies on this to keep a constant period.

Elisha Otis's 1853 invention did what?

Stopped an elevator falling if its cable broke: Otis's safety brake locked the car to its guide rails, and he installed the first passenger safety elevator at the Haughwout store in New York in 1857.

Who installed the first working escalator, an 'inclined elevator', at Coney Island in 1896?

Jesse W. Reno's 'inclined elevator', a cleated moving belt set at 25 degrees, ran at Coney Island's Old Iron Pier in 1896; Charles Seeberger later coined the word 'escalator'.

Otis lost its exclusive right to the word 'escalator' in a 1950 case because the public saw it as what?

A generic name for a moving stairway: in Haughton Elevator Co. v. Seeberger (1950) the US Patent Office found even Otis used 'escalator' generically, and the trademark was cancelled.

The original Ferris Wheel was built as a landmark for which event?

George Washington Gale Ferris Jr. designed the 80-metre wheel for the 1893 World's Columbian Exposition in Chicago as America's answer to the Eiffel Tower of 1889.

What powers a turbocharger, as opposed to a supercharger?

Exhaust gases spin the turbocharger's turbine, which drives its compressor; a supercharger is driven mechanically from the engine, so turbos were long called 'turbosuperchargers'.

Two or more meshing gears together are called what?

A gear train: the overall ratio of a train is the product of its pair ratios, and gears with separate pegs inserted as teeth are properly called cogwheels.

Rack railways use a rack and pinion, with a toothed rack laid between the rails, to do what?

Climb steep gradients: a cog wheel on the locomotive engages the toothed rack so trains can climb grades far beyond what wheel adhesion allows, such as the Pilatus Railway's 48 percent.

Which 16th-century Italian polymath gives his name to a common term for the universal joint?

Gerolamo Cardano (1501-1576) described the joint and the gimbal suspension that also bears his name; the plain U-joint is famously not a constant-velocity joint.

In a ratchet, what is the pivoting catch that stops the gear turning backwards called?

Pawl: the spring-loaded pawl drops into the teeth of the ratchet wheel so it can turn one way but is caught if it tries to reverse, as in a socket wrench or winch.

Ball bearings cut friction because the balls do what instead of sliding?

Roll: the balls roll between inner and outer races, replacing sliding contact with rolling contact that has far lower friction; usually one race is fixed and the other spins with the shaft.

The name of Hero of Alexandria's aeolipile comes from Aeolus, the Greek god of what?

The bladeless radial turbine spun on jets from a heated water container but was never a practical power source.

The horizontal or panemone windmill first appeared in the 9th century in which region?

Persia: the earliest reliable records of panemone windmills, turning on vertical axles, come from 9th-century Sistan in eastern Persia; the horizontal-axle mill only reached northwestern Europe in the 12th century.

The zipper takes its name from a 1923 brand of what?

Rubber boots: B.F. Goodrich coined 'zipper' in 1923 for its galoshes fitted with the fastener, which Gideon Sundback had perfected in 1913 after Whitcomb Judson's 1893 'clasp locker'.

Eli Whitney's 1793 cotton gin used what to pull cotton fibres through and separate them from seeds?

A wire screen and small wire hooks: hooks on a rotating drum drag the lint through a mesh too fine for the seeds, and a brush clears the hooks; 'gin' is short for engine.

The first sewing machine is generally credited to which Englishman, in 1790?

Thomas Saint, a London cabinet maker, patented a chain-stitch machine for leather and canvas in 1790; a model built from his drawings in 1874 needed modification before it would sew.

The first bush-roller chain patent, the basis of the bicycle chain, was filed in 1880 by which company?

Renold: Swiss-born Hans Renold, working in Manchester, patented the bush roller chain in 1880; the Rover safety bicycle of 1885 helped make chain drive standard.

In a steam engine, what does steam pressure push back and forth inside the cylinder?

A piston: steam admitted alternately to each end of the cylinder drives the piston back and forth, and a connecting rod and crank turn that push into rotation.

Who developed the first commercial steam-powered device, a water pump, in 1698?

Thomas Savery patented his 'Miner's Friend' in 1698: condensing steam created a vacuum that drew water up, then steam pressure pushed it higher, but the lift was limited to a few dozen feet.

Which engineer built the first full-scale railway steam locomotive, hauling iron in Wales in 1804?

Richard Trevithick's engine ran on 21 February 1804, pulling 10 tons of iron, 70 men and five wagons along the Pen-y-darren tramway at Merthyr Tydfil.

The American Society of Mechanical Engineers was founded in 1880 in response to what?

Steam boiler failures: ASME was founded in 1880 after a string of deadly boiler explosions, with Robert Henry Thurston of Stevens Institute as its first president.

What is the largest ASME standard, both in size and in the number of volunteers who prepare it?

The Boiler and Pressure Vessel Code, first issued in 1914-15, runs to many volumes covering the design, fabrication, inspection and care of boilers, pressure vessels and nuclear components.

Which more economical steam-generator design took over for marine use in the late 1800s?

Water-tube: with water inside the tubes and hot gas around them, these boilers raised steam faster and stood higher pressures, so navies adopted them from the 1890s; fire-tube boilers stayed standard on locomotives.

What was the name of the final experimental locomotive of 1808 built by the Pen-y-darren pioneer?

Catch Me Who Can ran on a circular track near Euston in London in 1808, offering rides for a shilling; four years later Matthew Murray's Salamanca ran on the rack-and-pinion Middleton Railway.

Cornish engineer Arthur Woolf patented which kind of steam engine, later near-universal at sea?

Compound: high-pressure steam expands in one cylinder and then again in one or more larger low-pressure cylinders; Woolf's early-19th-century engines revived Jonathan Hornblower's 1781 idea.

Which Chinese polymath of the 2nd century AD improved a water clock and invented a seismometer?

Zhang Heng (78-139) built a seismoscope in 132 AD that dropped a bronze ball to mark an earthquake's direction and added a compensating tank to the water clock; Su Song's astronomical clock tower came in 1092.

In which year did Al-Jazari write his Book of Knowledge of Ingenious Mechanical Devices?

1206: Ismail al-Jazari completed the Book of Knowledge of Ingenious Mechanical Devices that year at the Artuqid court in Diyarbakir, describing about 50 machines including his elephant clock.

Whose 1849 four-valve engine did the Rumford Medal committee call the greatest advance since Watt?

George Corliss patented his engine in 1849 and received the Rumford Medal in 1870; its separate admission and exhaust valves and automatic variable cutoff let it hold speed under changing loads.

Which Spanish inventor patented the first steam-powered water pump for draining mines in 1606?

Jerónimo de Ayanz y Beaumont, a Navarrese soldier and administrator of mines, received a 1606 royal privilege for a steam pump to drain mines; della Porta had described steam raising water in 1601.