Gear
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A gear or gearwheel, also called a toothed wheel, is a rotating machine part typically used to transmit rotational motion or torque by means of a series of "teeth" that engage with compatible teeth of
Bronze gear with pawl from Luoyang, China, dated to the Warring States period (475–221 BC)
Modern model of a south-pointing chariot
Wooden cogwheel driving a lantern pinion or cage gear
A cast gearwheel (above) meshing with a cogged mortise wheel (below). The wooden cogs are held in place by nails.
Geneva drive
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The Geneva drive or Geneva mechanism is a gear mechanism that translates a continuous rotation movement into intermittent rotary motion.
Gear
…gears are round and have equal teeth, designed to operate as smoothly as possible; but there are several applications for non-circular gears, and the Geneva drive has an extremely uneven operation, by design. Gears can be seen as instances of the basic lever "machine". When a small gear drives a larger one, the…
Movie projector with hand crank and Geneva drive