A differential is a gear train with three drive shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others. A common use of differentials is in moto
Differential unit for a rear-wheel drive car, built by ZF c. 2004
Differential gears (in yellow) in a punched tape reader, built by Tally c. 1962
James White's Dynamometer from A New Century of Inventions (1822)
Walter Hancock's Artillery Wheel with Driver allowing overrun on the outside of a curve
Antikythera mechanism
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The Antikythera mechanism is an ancient Greek hand-powered orrery built in the 2nd century BC and discovered in 1901. It is the oldest known example of an analogue computer. It could be used to predic
Differential (mechanical device)
…motor vehicles provide a gearing reduction by having fewer teeth on the pinion than the ring gear. The early history of the differential is obscure. The Antikythera mechanism (c.100 BC) is an ancient Greek orrery discovered in 1902 on a shipwreck by sponge divers. It contains about 30 gear wheels and could predict astronomical…
Derek J. de Solla Price (1922–1983) with a model of the Antikythera mechanism
Computer-generated front panel of the Freeth model
Front panel of a 2007 re-creation
Computer-generated back panel