The best Tech inventions of all time 4: Mechanical

Wheels have been around since about 5000 BC. Wheels, connected to axles and used as transport have been found dating back to 3500 BC, and spoked wheels since about 2000 BC.

Wheel bearings are used to reduce friction at the axle and prevent dragging, giving a smooth movement and reducing friction. Wheels are also used for other functions such as pottery, grinding flour, producing power, as in a water wheel, and automobile steering wheels.

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Archimedes screws lift water from low lying land to higher ditches. An Archimedes screw is a screw thread inside a pipe which rotates and moves fluids from one end of the pipe to the other.

Archimedes was credited with inventing the device in the third century BC. The devices are also used to move solids, such as rocks, fish can be moved from fish hatcheries, and grain on a combine harvester can be moved along the bed.

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Printing presses transfer ink from the inked surface to the media to be printed such as paper or cloth. The printing press was invented in 1440 by Johannes Gutenberg to replicate copies of the bible.

His press could make 240 impressions per hour. Movable type - using moveable components to produce letters or punctuation - revolutionised the printing presses and speeded up operation.

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The invention of the chronometer was a major technical achievement at the time. Before the chronometer was invented it was impossible to determine which longitude you were sailing along.

Watches were affected by fluctuations in temperature and humidity, and failed to keep accurate time as the watch winds down and the spring stretches.

Englishman John Harrison invented the chronometer which has a cone instead of a spring inside the clock. As the watch runs down the spring tension remains the same and the time remains accurate.

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Tension spoked wheels or suspension wheels are wheels that connect to hubs with thin and flexible adjustable wire spokes. Suspension wheels are considerably lighter than solid wheels and were introduced into cars during the 1920s.

The first Harley Davidson motorbike had tension spoked wheels. Spoke patterns such as radial and semi tangential, used to transmit torque from the hub to the rim, are used in differing load scenarios.

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American Walter Hunt invented the modern safety pin as we know it in 1849. His design included a clasp that covered the point of the pin to stop it opening, and used a spring to keep the pin tight in the clasp.

The design has hardly changed since Hunt's initial patent of the pin.

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If you attach an arm at right angles to something that rotates - say, an axle on a wheel, or another rotating shaft, the arm will move. You have converted circular motion to reciprocating motion.

A hand cranked salad spinner or a pencil sharpener are perfect examples of cranks.

Pedalling on a bicycle uses your leg as the crank to turn reciprocating motion into circular as the wheels turn. Cranks were first used in China for turning silk onto reels and for spinning hemp in 200 BC.

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Tires were originally made of leather and bound to wooden wheels. Steel and iron followed, forged whilst still hot onto wooden wheels and cooled down by water. The first rubber tires were fixed to wheels and were solid which caused jarring over rough ground.

In 1888 the first pneumatic tires, filled with air, were made for bicycles and light vehicles. Automobiles initially had solid tires, but in 1900, the first air filled tires were fitted to cars. Now, over one billion tires are produced every year.

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The hydraulic press is a device used to deliver compressive force by use of a fluid filled cylinder. The cylinder is moved by a piston. All of the components are parts of a closed fluid filled system where the pressure remains constant.

The press was invented in 1795. Hydraulic presses are used to mould items such as car doors and fenders. Brake fluid is an example of a hydraulic fluid used to exert pressure on a brake pad via a small bore hydraulic tube.

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Disc brakes have been used in motor cars since 1902. They exert force on a disk causing friction which slows the spinning disc. Pads are fitted to the disc brake to absorb waste heat produced so that the disc does not overheat and warp.

Disc brakes are more efficient than drum brakes. In drum brakes, the brake shoe pushes outwards onto the brake drum. Drum brakes do not cool down as quickly as disc brakes.

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CT (computed tomography) scanners take X-ray images from different angles to produce cross sectional images of the scanned object. This means that the inside of the object can be seen without cutting into it.

Egyptian mummies are scanned to determine the location of objects within the wrapping and to identify details of the person within. The object is cut into scan slices so that detailed analysis of the object can be undertaken. CT scans are used in industry to detect flaws in objects.

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